Ok so I had been looking for a project for awhile and I came across a 89 Formula w/ a 305 TBI with wiring problems. The guy was fed up with it and wanted it gone 400 bucks. So I bought it, may not have been my best idea but hey whatever. Anyway the body is in good shape the Lexan t-tops are busted and the seats could use some upholstry but thats not to be worried about right now, the key doesnt do anything.

I after a week of replacing burnt wires, pesky fusible links and an ignition switch the car turns over and starts !! surprise !! Unfortunately the racket that came from the engine department didnt so much resemble the good running motor that the guy said it had, yet again im real surprised. So here I am I have to now decide if I should just get a short block 305 and toss it in or if I want to go to all the trouble of going to a 350. If I knew someone that had done it locally (St Louis) I would do it in a heartbeat but with only the disjointed ramblings of these forums I'm not sure that I want to tackle the swap. There are lots of suggestions of what to do but half of them contridict others and its almost impossible to figure out. If this damned town didnt have emmisions reqs Id just put a vortec 350 with a carb and be done, but there is also things to be said about throttle bodies and EFI in general that I just havent learned yet.

Anyone in or around St Louis that has actually done this? Anyone have any suggestions about the motor situation? I dont want to race the car but I don't want a doggy car that won't turn the tires either, having never had the chance to drive one with a working 305 I dont really know what to expect.

Any and all suggestions will be appreciated.

Thanks.

 

i'd just find a 350 and drop it in, good power and it won't cost you much more than a 305 if at all.

 

Good job fixin it! A 350 is no harder than a 305 to put in.

 

The question here is, how much money are you willing to spend? If emissions are a factor, yet you want to go fast, but need a reliable set-up.... then swapping to either an LT1, or LS1, may very well be what you are looking for.

Upgrading to a 350, from a 305 is an awesome idea.... but then you need to consider which "system" to go with (TBI, or TPI... you can't go carb, being emission oriented). Plus, it can get very costly in the long run by trying to piece together a decent setup.

Consider an LTx/LSx engine swap. There cheap enough nowadays, and are completely street legal. There's more than enough information on these boards to help you get it done in a single weekend (when planned properly)...

 

Thanks for the feedback. I think I have decided to to a 350 upgrade, the only problem will be getting the proper tune since I know nothing about it, don't have a laptop and don't know anyone that does it. I would love to get into it but without some first hand advice would be worried about screwing stuff up not to mention that I dont want to be trying to get a tune right on an engine that I haven't started yet.

Later

 

call Tim.. 314-221-1291 hes from STL
hes really helpful and knows these cars real well
tell him Tony sent ya

 

Just go with a LO5 knock sensor, LO5 prom, and an adjustable fuel pressure regulator. I'm not saying that you'll be tune free here... but it will in fact get you back on the road.

Good luck w/you're choice!

 

Thanks Tony I will have to give him a call. I found a 350 TPI in OFallon for 600 with a wiring harness. That guy also has a 350 TBI with no wiring for 350 so one of those ought to get me back on the road. Although doesnt the TPI require a larger fuel pump?

 

The 350 TBI is the LO5. If it comes complete with the knock sensor and throttle body, you'll just need to change you're prom/chip in the computer to a LO5's (or simply get one burned for you're application).

Yes, the TPI does require a different fuel pump. It's not worth the swap, believe me. You'll make just as much power with the TBI, if not more, in the long run...

I just hate to see someone go through all that trouble of swapping engines, getting the thing to run "right" after weeks and weeks of trial and error, then in the months to come, start throwing parts at it to try and get it to run in the low 13's, high 12's.... when swapping to a LS1 will immediately put you there (if this is what you're ultimately after of course, and you will be, eventually).

I have a Holley ProJection intake manifold lying around for the TBI. It's already ported, comes with 2" bores, and in great shape. If you want it, it's your's (I no longer need it). Should help net you a little more power. PM me if you're interested, although I'll still emphasize to; Go the LS1 route....

 

The TBI motor comes with all the sensors and the throttle body, its out of a wrecked van. So all I would need would be the PROM chip. I realize that the LS1 would be a lot of fun but I dont have the time or energy to find one and rewire the damned thing. Right now I just want to drive the car and have some fun in it. I dont think I will be taking it to the track anytime soon. I'm sure I will get the fever after a year or two but by then I will have a running car and I can take my time preparing for the engine swap. As it is now I have 2 broken vehicles and garage space for one. Will have to push the Bird out of the garage to replace the head gasket on the Fiero Sunday. Thanks a lot for the advice and I will probably PM you about that intake.

Thanks

 

I hear you, so lets focus on you're LO5 swap then. You have a great deal of help from the forum members headed you're way, as everyone here knows these engines inside and out...

 

Like the other 5 billion post on the subject, you need this

350 chip from a caprice with a 350
350 knock sensor
350 ESC module
350 injectors or whole throttle body

Thats it, nothing too confusing about that. If your going with a bone stock 350 then you won't need a custom tune. GM will have your chip.

 

Thanks for the help guys I think I am on my way. I know this information is on the board I read it, LOTS of it but it's good to get a contact or two that will be able to give me some help.

 

Hold on there, cowboy; let's not go crazy here.

First, I vote the L05 swap; BUT that is an incorrect statement.

Stock for stock, the TPI makes significantly more horsepower. More Importantly, it makes GOBS more torque.

He can get to 300, even 350 hp cheaper with the TPI than he can with the TBI. He's not going to run into a big cost differential until he has to start buying a base and runners.

If he's patient, he can save a lot on that, too. A friend of mine picked up a TPIS Big Mouth base and AS&M runners off of ebay last week for 400.

Swapping to a TPI would be a lot more difficult than it would to swap to a 350 TBI. For starters, everything is on the wrong side on a TBI Firebird, so a factory airbox won't fit, etc. Swapping out the harness and fuel pump will be a bitch, too.

The L05 will make a good starting point for a solid street motor, he won't have to change the harness or fuel pump and all he'll need is a stock L05 chip for his existing ECM as a starting point. He can make good power with it with lots of room for incremental upgrades along the way, but it's wrong to tell him he'll make "just as much, if not more" power with the TBI. Just not the case.

I love my TBI, but, when I bought it, if there had been two otherwise identical cars to choose from for the same price, one a TBI and the other a TPI, I'd take the TPI in a second. TBI is what I have, and I don't believe it's worth the expense and effort to swap to TPI, but TPI is clearly a more efficient injection system, it's easier to make power with, and there are more power parts readily available for it.

The one true benefit I see developing for TBI over TPI is rbob's Embedded Lockers. There's nothing like it available for TPI, but, I think it's just a matter of time before rbob comes out with a TPI version of it, or a TPI afficianado with similar skills than rbob's takes the idea and runs with it.

My TBI reminds me of my 73 Gremlin X. I swapped the 304 out for a 401 and hung a 9" Mustang rearend under it. I loved that car, but it was always a bitch to find parts for it, they cost A LOT more than the same parts would for a Chevy, and I took a lot of guff over it. Still, I enjoyed being "different", and it was hard for the guys with the Camaros, Chevelles and Novas to keep giving me grief after I smoked 'em with my 2800 lb wonder.

I see people on here modding their TBIs either because that's what they have, or because they take pleasure in being different, or doing something most people think can't be done. Either is cool, but I don't think we should let our zeal for TBI overcome our grip on reality.

 

Come on now, you know you wanna jump on the bandwagon... yeeeehaww!!!!

 

Hmm well a tbi can make torque over 4500rpms with a good settup wonder where TPI would be.

 

Dollar for dollar I think you can make more power with TBI. A 454 TB for around 150 - 200$ used, plus a performer RPM or Wiend stealth intake for 160$ will make 400-450 HP no problem. To get a 400 HP TPI will take much more money than that.

You also have to remember that TPI made more power because it had bigger exhaust, better heads, and a much better cam. It wasn't just because of the intake system or where the fuel was injected. We can argue this for hours if we want to, but we just won't know for sure untill some one does some dyno testing with both systems. I bet you would end up with more HP with TBI, but less torque. HP under the curve is all that matters, and which system would work out the best is anyone's guess.

 

Come on Monte, you know better. I don't understand why you get so defensive anytime anyone says something you percieve as being derogatory to TBI. I said I LOVED my TBI, but, I also accept it for what it is.

ummmm .... it's gonna take a few more parts than a 454 throttle body and an intake to get to 400 hp, BUT, induction aside, since both the TBI and the TPI would take essentially the same parts, let's make the comparison on the parts they don't have in common. 150 for the throttle body and 160 for the intake, vs. 400 for the used big mouth base and AS&M runners. Figure another 300 for a bigger throttle body and injectors. Yes, it would cost more to get to 400+ hp with a TPI, BUT:

1. I clearly stated in my post that it would be cheaper to get to 300-350 hp; not 400-450hp. With an L98, you can EASILY achieve 300hp with the stock intake setup, where you cannot with the TBI, so you're at least 300.00 in the hole with your TBI to get there.

2. Don't forget that a Stealth Ram intake is only 299. 400 more for fuel rails, injectors, etc puts you into a setup capable of 500 hp cheaper than you can get to 400 hp with the Big Mouth base and AS&M runners, and that's buying the parts new. I've seen a complete Stealh Ram setup (minus the PCM) go for 450 on ebay, used.

3. Most importantly, I am still waiting to see proof of ANY small block TBI making 400 hp, much less 450. You keep talking about it, but I've been on this board for over 3 years and have yet to see one. Go over to the TPI board and you can see plenty of TPIs that make that power. You hear a lot of theoretical talk on this board about 400hp+ TBIs, but you don't see them. I believe the reason for that is it's A LOT harder to get there with a TBI than with TPI. Before you start talking about "dollar for dollar" again, you still have to show it has even been done.

You're making MY point. Yes, the L98 has better heads; heads that he can get to 300-350 hp with, without having to yank them off the car to port or replace them. He can't get there with the L05's swirl port heads (unless he pulls them off and ports them). That means even more expense to get to the 300-350hp mark with the TBI, and proves that the L98 would be a better starting point.

And the exhaust? I put what is arguably one of the free-est flowing bolt-on exhausts possible for our cars, and picked up 7 hp. Granted, that is without tuning, but the MOST you can expect to get from a full exhaust upgrade after tuning is 20-25 hp, and that's an unfair comparison, as the original exhaust would have been on the stock, conservative tune, but the new exhaust would be on an optimized tune. If you optimized the tune with the stock exhaust, did the exhaust upgrade, then optimized the tune again, I'm convinced you're looking at something more like 15hp, maybe 20. There's just no way there's more than a 10hp difference between the stock TBI exhaust and the stock TPI exhaust, and that's being generous.

The tech section on here lists the L03 as 170hp and 255lb/ft torque. There are two listings for the LB9; one showing 205hp and 285 lb/ft torque, and another showing 230hp and 300lb/ft torque (I know we're talking about 350s, here, but I'm comparing 305 TBI to 305 TPI, as they were both available in our cars and that's the information that's available). Taking the lower LB9 figure, that's a 35 hp and 30lb/ft difference. That's significant, any way you look at it, especially when you factor in the fact that the TBI's swirl port heads will cause all of the basic hot rod mods (exhaust, ignition, etc.) to yield less on the TBI than they will on the TPI, with it's better heads. The nearest 350 comparison you can make is an l98 TPI, making 245 hp and 345 lb/ft torque in a 91 Firebird, and an L05 in a 92 Impala, which made 205hp and 300 lb/ft torque. That's a difference of 40 hp and 45 lb/ft torque, an even greater differential than the 305 TBI to 305 TPI comparison. Simple logic dictates that the TPI makes a better starting point than the TBI, everything else being equal. I'll take a 35hp head start any day of the week.

GM offered TBI as a lower-cost, cheaper-to-insure alternative to the more performance-oriented TPI. That's WHY the TPI car has better heads, better exhaust, and a better cam. You continue to offer that as an excuse, when what it is is a DESIGN ELEMENT. TBI was never designed to compete with TPI, it was designed as a lower-cost ALTERNATIVE to it, yet you insist that it is as good or a better performance platform that TPI. That's just silly. It was never designed for that purpose. TBI is to TPI what a 2bbl carbed 350 69 Camaro is to a 4bbl carbed 69 Camaro. Now, you can have a great time and make a lot of power modding either, but, unless you're planning on immediately pulling the motor and redoing EVERYTHING, you'd be better off starting off with the 4bbl Camaro, all other things being equal. That's neither bad nor good, it simply is what it is.

I'm not saying there's anything wrong with TBI, I'm simply saying it was not designed with performance in mind and has limitations. I don't understand why you have to get so emotional about it; why anyone suggesting TBI is not the BEST must be WRONG. You know, I love my dog more than any other dog in the world. He's not the smartest dog; he's not the best looking dog; he's not the best-behaved dog, and he doesn't have to be for me to love him. He's just mine, and that's good enough for me. My affection for him doesn't cause me to INSIST that he's "better" than anyone else's dog. Someone isn't denigrating him when they say their dog is smarter, or bvetter looking, or better behaved (unless they're LYING; then, IT's ON!!!!). Yes, you can absolutely modify your TBI to make it a nice, torquey, fun street car, but there's no way you're going to make it a 450hp fire breathing monster. Again, show me one.

Finally, a direct-port, dry-flow injection is simply, inherently more efficient than a wet flow injection system. There's just no getting around that. It doesn't make TBI "bad", it just makes it different. Again, it is what it is. You may be the biggest Kelly Clarkson fan in the world, but it doesn't make sense for you to get mad when someone says Jessica Simpson has bigger *****. It is what it is ... errrr ........ they are what they are.
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How does a TBI make torque at over 4500 rpm when it noses over completely at 4800? The "good" TBI setups on here don't rev all that much higher, while a "good" TPI setup pulls well through 5500. Go to the TPI board and do a search. There are plenty of TPIs in the low 12s, making well over 400hp. Show me a TBI doing that.

Within it's limits, TBI is great; reliable, torquey, more efficient than a carb, good to 300-350 hp. I don't understand why you guys insist it's something it's not. Every project doesn't have to make 500hp and run 11s to be a success. Just because TBI can't reach that level of performance doesn't make it junk, and it's not necessary for people who like TBI to INSIST that it can make power it can't. My old Uncle Elmo" used to say: "You can't fit two tons of fertilizer in a one-ton truck. You can stuff all you like, but all you're going to do is end up being full of ....... fertilizer".

 

Sean, there was absolutely no emotion in my last post, your the one getting all upset. We can go back and forth on the price thing, but it's much easier to find used GM BB TB's than it is to find used aftermaket runners and bases for TPI. Your post made it sound like the induction system was responsible for making power. You never mentioned why a TPI setup made more power, you only made the statment that TPI makes more power than TBI.

Can you tell me why TBI is not "performance oriented", the motor they were attached to deffinately were not. This guy has a blown TBI motor, I'm suggesting he learn to burn his own proms and stick a long block under his TBI and make some power. I don't think it neccesarry to swap to TPI to make power. I just don't see where a dual 51mm throttle body attached to a cheap high flowing carb intake is going to be miles behind a TPI setup that was designed for a 305. People pick up 30-60 HP just by swaping to another form of MPI system.

When it comes down to it, I would take a wet flow system with a 51mm TB and a 6.5" runner length with twice the runner volume of a system with a 48mm TB and a 16" runner length.

Edit: I just noticed this line.
Uhhh, my little ole 350 peaks out at 5200 RPM and pulled to 6000. I'm pretty sure Rbob's 327 peaked even higher than that. There is NOTHING inherent in TBI that would keep it from reving higher. There IS something in herent in TPI that limits it's effective RPM range and that is runner length and size. A 1.5" by 16" long runner does not want to flow lots of air at high speed. It wants to use sonic resonance to jam more air into the motor at low rpm's.

 

There is nothing "upset" in my post; every thing I've said has been calm, reasonable, and supported by facts. I believe it is you who is emotional because time and again, I see you making emphatic, illogocal statements anytime someone suggests TPI may be better than TBI, yet you never are ablue to support those statements with facts and example. Please show me one example of a naturally aspirated small block making 400-450 hp with a TBI. You ignored that from my last post. Again, you made the statement, now plase provide examples.

Yes, I said that, in response to Street Lethal's saying: "You'll make just as much power with the TBI, if not more, in the long run... "

That is just not correct. You could take two ZZ4 crate engines, bolt a stock TBI on one and a stock TPI on the other, tune both properly, and the TPI would make more power. From that point forward, every upgrade you could make to the TBI could be matched dollar for dollar on the TPI and the TPI would make more power. Your 300 for the intake and throttle body could be spent on a set of used SLP siamesed runners, a bigger throttle body and porting the base and plenum. The TPI would make more power.

Yes, getting to the 400-450hp mark would get very expensive, but you CAN get there with a TPI. I have yet to see ANY small block TBI make that kind of power, and I still firmly believe that, if you found one, you couild bolt on a maxed-out TPI setup and make more power.

But that's not even relevant here. This isn't a question of induction systems, this is a question of ENGINES, which use particular induction systems. Street Lethal's statement was made in response to this kid's asking whether to put in an L05 or a TPI ENGINE. There is absolutely no question that the L89 would make more power than the L05. It has better heads, a better cam AND a superior induction. It also has 4 bolt mains, and an oil pump that has enough pressure for performance applications. To get the L05 to equal the L98's performance, he'd have to change ALL of those (well, not the 2 bolt mains, although the 4 bolt main engine is clearly preferrable).

First (but, for the second time), I recommended that he STAY with the TBI. Keep it. Hold on to it. NOT change it. A bird in the hand is worth two in the bush, and the expense of swapping over to TPI is not worth the performance improvement he would see. If he'd started with a TPI car, it would be different, but, since he started with a TBI car, my recommendation was that he stay with it. This does not change the fact that MPFI is more efficient than wet flow; that an L98 makes more power than an L05; and that TPI is a more efficient induction system than TBI. I NEVER said he had to swap to TPI to make power, I said Street Lethal's statement that he'd make just as much, if not more power from the L05 TBI was incorrect, and it is. It was you who overreacted to my statement, taking it as an "attack" on TBI, and began putting words in my mouth, as you have done on numerous previous occasions.

And as far as TBI not being "performance oriented"? Where do you want me to start? Could it be that big old injector pod hanging right in the middle of the airstream? I'm pretty much thinking the first priority of any performance induction setup would be unimpeded airflow. Could it be the inability of two injectors to supply sufficient fuel for high horsepower applications? I know you're going to argue that point, but everyone in the industry I've spoken to says you can't get 400hp out of a small block TBI because you can't fuel it. Before you argue the point, provide ONE example of a small block TBI making that kind of power. The big block trucks that make that power are extreme examples that cannot be duplicated by people with average mechanical skills and would, I believe, make more power for less money with other MPFI setups. More importantly, I'm just not going to go there with you until you back up your supposition that there are 400-450hp TBIs until you show me some.

And once again, you compare apples to oranges. You want to compare a TBI setup with a big block throttle body and an aftermarket intake to a stock TPI.

You take your 51mm throttle body and carb intake, I'll take a TPI with a 50 or 52mm throttle body, SLP runners and ported plenum and base and walk the dog on you all day long.

While I agree TPI's LTRs limit the airflow and revving potential, the system makes incredible torque, just as it was designed to do, and torque is what moves you down the road. As good as our TBIs are at making torque, TPIs are better. Gm apparently agrees. While they went back to a short-runner design with the LT1, they went right back to longer runners with the LS!. Ford and Mopar all have similar systems, as well.

Ummm ... just as you plan on getting past TBIs inherent airflow limitations with bigger a bigger throttle body and carb intake, you can do the same with the Big Mouth base, AS&M runners and a bigger throttle body. That combination will pull to 6000. If cost isn't an object, you can extrude hone the plenum, runners and base and get to 6500.

That's not saying I do that, however. just as TBI has it's limitations, so does TPI. Past 400 hp or so, it would actually be cheaper to swap to a Stealth Ram than it would be to get the power out of a TPI.

I have a TBI car. If my goal was 375 hp or less, I'd stay with TBI. If my car was a TPI, and my goal was 400hp or less, I'd stay with TPI. Since my eventual horsepower goal is greater than both, I will be going with another induction system. You don't bring a knife to a gunfight.

By the way, if, as you suggest, TBI is as good or better than TPI, could you show me an example of anyone yanking their TPI out to go to TBI? Where is the tech article on that swap? Oopps, there isn't one. I guarantee you, if you CAN find one, I'll find ten or more examples of people swapping from TBI to TPI for every TPI-TBI example you can come up with.

What I don't understand is why you feel it's necessary to turn something as simple as correcting an inaccurate statement into a debate over the inherent flaws and benefits of TBI and TPI and to hijack this kid's thread.

He asked a simple question. Should he replace his lunched TBI ENGINE with an L05 or the 350 TPI (which would be an L98). While the L98 would CLEARLY and ABSOLUTELY make more power than the L05, my recommendation was and is that he stick with the TBI, as the performance GAIN he would see with the L98 wouldn't be worth the extra expense and effort. I will also again, and for the last time, say that Street Lethal's statement that the TBI will make as much or more power than the TPI is wrong.

 

I don't have the time to go line by line with you, and you are obviously upset or you wouldn't have countered with that monstrosity of chest beating.

You and I both know that an L-98 long block will make more power than a LO5 long block. I'm not arguing this fact, you are. What I am saying based off of what I've done, and what several other members have done that you're going to make the same HP, probably more with a cheap carb intake and even a stock SB throttle body on identical long blocks. No I don't have before and after dyno prove, but you don’t have prove that it won't. I do have hours and hours of data logs that show that a stock TB does not pull any vacuum until 300HP and that a BB unit just starts to pull a vacuum at 400 hp. Look into Ben73 if you want prove, he runs a 12.4 with a cross ram and a set of single barrel 2" TBI's. As for fuel I'm running 22 psi on 70 lb/hr injectors and it feeds my 300 fwhp motor at 70% duty cycle. With my handy dandy calculator I can see where 90 lb's at 30 psi will support north of 400 hp.

As long as you don't restrict air entering your engine, you feed it the correct amount of fuel, and the runner length is tuned to your operating range your getting all you can out of an induction system. TBI meets all these needs and give you the advantage of getting a runner length that is tuned more for performance. That’s where it's better than TPI. Wet flow does NOT effect power at WOT. It does require different tuning methods and will have higher emissions but does not affect power.

I'm done here, this is going no where and I'm not going back and rehashing 5 years worth of info from this board for you.

 

Well, you're sure running true to form. You can't counter the debate, so you start getting personal, knowing a moderator will shut down the thread and get you out of the hole.

But, that's what the whole thread is ABOUT. He is trying to decide whether he should get the COMPLETE L98 ENGINE, or the COMPLETE L05 ENGINE that the guy in O'Fallon has. YOU are the one who reframed the discussion, not me. For once, READ the post before you start typing!

And once again, you insist on comparing a MODIFIED TBI induction system to a STOCK TPI induction system, then insisting the TBI is better. On the same long block, stock TBI induction vs. stock TPI induction, TPI will make more power. $300 worth of mods vs. $300 worth of mods and TPI makes more power. $600 worth of mods vs $600 worth of mods and TPI makes more power, etc., etc., etc., and so forth. As long as the playing field stays level, TPI stays ahead.

MY point, that, given the choice between an l03 and a LB9 when I was buying my car, with all else being equal, preferring the LB9 makes absolute sense. The LB9 has better heads, a better cam, and a superior induction system. Why would anyone NOT want to start out with 35 additional hp and an additional 30 lb/ft torque? When the cars were new and there was a 5000.00 price differential (not to mention MUCH more expensive insurance), you could make a case for going with the TBI and investing part of the savings in modifications to get the power up to the TPI level, (Hot Rod's Project F-Notes in 1989, something people on this board scoff at every time it's broght up) but now, when there is little or no price differential, PREFERRING the TBI just does not make sense. I knew that when I bought my car, but, so much else was right with the car that it offset any slight downside of TBI rather than TPI. I've never regretted the decision I made.

Here you go again. I again challenge you to prove your "400-450 hp TBI" statement, and you again drag out the crossfire Vette. Once again, we are discussing GM's TBI system, as installed on a Third Gen Camaro Or Firebird, not a CFI with a HUGE plenum running 12.40s in a car that is 400 to 500 lbs lighter than a Third Gen. You have yet to supply a single example of a naturally aspirated TBI making 400 hp, much less 450.

And you can calculate all you like, but there is one simple, GLARING fault in your argument ... WHERE IS IT?

Where is the 400hp TBI? You assert it's doable, there are plenty of knowledgable people on this board attempting to get more power out of their TBIs, so where is it?

400 hp isn't that big of a deal anymore. The heads available today are so good that 400hp is easily doable. A STOCK short-blocked, cast-pistoned, $1000 (at the time) Goodwrench 350 made 408 hp and 430 lb/ft torque with the addition of a set of Vortec heads, a Comp Cams 477/480 lift, 230/234 duration cam, a Performer RPM intake and a 750 Holley carb (The Goodwrench Quest, Part V). That's certainly not an exotic combination, and you see similar results all the time with those heads (they went on to make 416hp with off-the-shelf TFS Twisted Wedge heads in Part VI). It's common to make upwards of 450 hp with even better heads, as Super Chevy did with Danger Mouse, a pair of 1100.00 Edelbrock Etec 170s and a 650(!) Road Demon. I can buy a crate 350 from Edelbrock that makes 435hp and comes with a two-year, unlimited-mileage warranty! 400hp just ain't that big of a deal anymore, so where are the 400hp TBIs?

Even though I was told a cam with 230 duration was too big three years ago when I first joined this board, I was POUNDED several months ago when I said that, and you were one of the pounders, INSISTING that a cam with 230 duration COULD be tuned on a TBI. OK, then, since the problem isn't the cam, that only leaves the induction system. There are plenty of people on here with 350, Vortec-headed TBIs, so where are the 400 hp cars?

There are a number of TPI cars making that number with Vortec heads, go read the TPI board. So, where are the 400hp TBIs?

As I write this, there are 21 people viewing the TPI board, and 11 viewing the TBI board; about twice as many. There are 21,700 threads on the TPI board, and 11,671 threads on the TBI board, again, about twice as many. For the sake of this discussion, let's say that there are two TPI members for every one TBI member. Based on that ratio, it's reasonable to expect that there would be one 400hp TBI car for every two 400 hp TPI cars. I read that board occasionally, so I feel comfortable saying there are at least two 400hp TPI cars (there are actually quite a few more), so where is the ONE 400hp TBI car?

Employing simple deductive reasoning, the fact that there are 400hp TPI cars and there are no 400hp TBI cars leaves us with a limited number of possible conclusions. We've eliminated the cam as the weak point, as you and others recently STRONGLY asserted, it CAN be tuned for a TBI, so the choices left are:

a) TBI owners are too stupid to make 400hp

b) TBI owners are too lazy to make 400hp

c) TBI owners are too cheap to make 400hp

d) GM TBI induction cannot make 400hp.

I think it's pretty easy to eliminate a), b) and c), so that leaves us with one simple choice, doesn't it?

EXACTLY! We've been looking for a 400hp TBI for FIVE YEARS, yet there are none. Those Vortec heads have been available for most, if not all of those five years, yet there are no 400hp TBIs. People with carbs have been routinely making 400hp for most, if not all, of those five years, yet there are no 400hp TBIs. People with TPI cars have been making 400hp for some, if not all of those five years, yet there are no 400hp TBI cars. Where are they?

You can attack me all you like, you can talk about your calculator and how much vacuum you pull, or your fuel pressure all you like, but the simple fact is that, after all this time and "discussion"; after all of these YEARS, you can't produce a 400hp TBI, yet, you can go on the TPI board and see plenty of them.

It's time you stopped blaming me for the fact that you can't prove your point.

 

This really sounds like a personal arguement between you two members, so I'd rather not get involved.... but I at least wanted to try and clarify the arguement though, because I'm confused. Are you arguing that an LO3 can't make 400 horsepower, or the LO5? I'm imagining that this in reference to the LO5, because I haven't seen any n/a 305-LB9's making 400 horsepower anywhere.

 

I'd be glad to see ANY small block making 400hp with a TBI. I'll eventually be dropping a 6" rod 383 in my car. My horsepower goal is 450, and NOTHING would make me happier than to get there with my trusty TBI. Hell, I'd give up 50hp to keep my TBI, I love it! For some reason, monte assumes I HATE TBI simply because I have come to accept it's limitations. Anytime anyone says anything other than TBI being the be-all; end-all, he comes out swinging.

What's funny is that, 3 years ago, when I stated my goal of making 400+hp with a 383 or 406 and TBI, I was the one being told it couldn't be done. I didn't buy it, so I spent a lot of time researching it, and eventually (and regretfully) came to the conclusion that they were right.

The fact that there are limits to the power you can make with TBI doesn't mean TBI sucks, but it's apparently all or nothing with monte.

 

It's simple, Sean doesn't think TBI can make 400 HP because it hasn't been done here on these boards with dyno graphs. I know it can be done because I've spent enough time tuning on these things to know what it will take.

Sorry Sean I can't give you the thread that shows the TBI system with both throttle bores side by side (not crossfire) and a dyno sheet showing 400 HP. It's been done plenty of times with a BB, but that doesn't count does it?

I give up, your right TBI isn't capable of more than 275 rear wheel HP since that's all thats ever been posted on here. Like I said earlier I don't have the time drag out my notes and rehash everything I've learned over the last few years so I'll bow out of this one and leave you with the "win". I'm wrong your right. Feel better now?

Edit:

I'd like to add that the reason I'm not argueing this any further is that you don't want calculations or datalogs proving that there is room in the system to make the power, you want hard dyno proven facts and quite frankly there aren't any. I'm not bothering to do your homework for you and dig up the threads that lay out all the math so you can calculate how much fuel and air you need to support XXX HP, it's out there and I've verified with my setup that they are correct. But that's all useless "conjecture" and it isn't possible untill it's common practice. You just can't argue with that kind of mentality.

Just answer one question Sean, do you even burn your own proms? If you don't how in the hell would you have half a clue as to what is going on with TBI or any FI system for that matter other than to take other's word for it.

 

You were the one who insisted you could make 400+hp with a TBI, all I have done is hold your feet to the fire, insisting you produce proof of it. You can make all the passive-aggressive "you win" statements you like, but the bottom line is you can't back up your assertion. Furthermore, I will GLADLY admit I am wrong as soon as you show me a 400hp, naturally aspirated small block TBI. I would be ecstatic to do it. Happy! Happy! Happy! I DON'T want to dump my TBI.

Trust me, if someone on here had done it, there WOULD be dyno graphs posted. Anyone doing what so many have said can't be done would LOVE the vindication. That was actually my plan when so many told me it couldn't be done. I was going to SHOW those guys!

But, when the guy at Cfm Technologies, tells me it can't be done, I have to take him seriously. He is in business to SELL parts, not turn away business. Why would he tell me NOT to buy his parts.

When the guy a Jet Performance tells me it can't be done, I have to take him seriously. He is in business to SELL parts, not turn away business. Why would he tell me NOT to buy his parts.

When the guy at Holley, and the guy who sells the bored out 454 throttle bodies, every single onel of the other people I talked to who are in the business of selling people parts to make their TBIs faster unanimously tell me it can't be done, and all of them are listing the same reasons, I have to give them some credence, especially after I got pissed at that JERK engineer at Holley who INSISTED I could not make 400+ hp with my TBI and came back on this board and read every single post from the beginning JUST so I could rub his smartassed nose in it, and was faced with a simple fact. There is not a single documented 400hp naturally-aspirated TBI small block on here.

No matter how passionate you may be, when every single knowledgable person you talk to says you are wrong, and you can find NO one in your universe who has done what you hope to do, you have to be willing to reconsider your position. I did, as much as I hated to. As far as I'm concerned, the 400hp TBI is thirdgen.org's version of cold fusion. Everybody talks about it, but no one's done it. I'm hopeful that someone will, and that they'll do so BEFORE I go to my Mass-Flo EFI. If they do, I'll be the first to congratulate them, and the first to ask them EXACTLY how they did it, so I can try and duplicate it.

 

I honestly don't frequent this forum as much as I should, and sadly, I'm not too up to speed with the majority of everyone's setup. Does anyone remember what Pablo was able to squeeze out of his LO3 (before he threw the carb on it)? Has anyone successfully tuned a cam much larger than the LT1 (I'm talking dialed in, on a LO3). It's been awhile, so bare with me...

 

But you ARE arguing it further, aren't you?

Dude, this is actually funny. You keep trying to reframe the argument, to bully me off of my position, to get yourself out of the hot seat, and you're ABSOLUTELY determined to have the last word. Now you challenge my credentials; if I don't burn chips, I have no business disagreeing with you.

I don't burn chips. When I realized I couldn't reach my horsepower goals with TBI, buying the equipment to burn chips and learning how to do it became moot, so I focused on suspension, brakes and infrastructure. Only after I've done the C5 brake upgrade, installed the 1LE 9 bolt, lowering springs, shocks, struts, T56 and the wheels and tires will I pull my poor old L03 out and put power in.

I will readily admit you have greater mechanical and engineering skills than I do, and, you know what, that doesn't mean squat. Finding out what the limits of my TBI induction were was an exercise in research; now you're in my world. I built a successful career on a simple fact: you don't have to know something, you just have to know how to find someone who knows something. When I don't know, I find an expert; preferrably several experts, and preferrably THE expert.

You may very well be an accomplished engineer, well-versed in the theories and formulae in play here, but, I have to think the Chief Engineer in charge of EFI at Holley has some idea of what he's talking about, too. I have to think the guy at Jet Performance who tuned the TBI 305 for Chevy High Performance everyone was talking about the summer before last has some clue as well. When they, along with EVERYONE else in the make-TBIs-go-fast industry I spoke with are all independently saying the same thing, I have to think they might be on to something, but, you know what, they could all be full of crap.

There is one piece of simple logic, however, that that snooty, smug, rude-assed guy at Holley posed to me that you simply can not get away from:

The parts to make small blocks make 400+ hp relatively inexpensively have been readily available for close to 10 years.

Guys with carbs have been taking those parts and making 400+ hp for close to 10 years.

Guys with TPIs have been taking those parts and making 400+ hp for a number of those years.

Where are the 400 hp TBIs?

I looked, and I can add to that. His argument has become even more relevant, as there are plenty of guys on the carb boards, there are plenty of guys on the TPI boards posting those 400+ hp results; why none on here?

There is only one logical conclusion.

Now, monte, I can tell you, you're not going to push me off of this hand. I can't be bluffed or bullied, and all of your bluster isn't going to change one simple fact; the fact that this will ALWAYS come back to:

YOU insisted TBIs could make over 400 hp. Ok; back it up. Show me one naturally aspirated small block TBI. It's that simple. you're an engineer, you are about facts, not conjecture. Prove your theorum.

If you can, congratulations, I will readily admit I am wrong.

If you can't, shut up until you can.

 

https://www.thirdgen.org/forums/tpi/...feb-super.html

This is a sticky on the TPI board. Someone had scanned the pages of the actual article, I read it some time ago, but they're not showing up now. The summary, however, says it all:

"Stock TPI (410hp, 500lb-ft)
Edelbrock High-Flo (431hp, 501lb-ft)
Extrude Hone base & LTR (451hp, 534lb-ft)
TPIS Big Mouth System (460hp, 534lb-ft)
ASM Siamesed Runners (464hp, 510lb-ft)
SLP T-Ram (466hp, 495lb-ft)
Accel SR (480hp, 506lb-ft)
Holley single plane (493hp, 480lb-ft)
HSR (501hp, 493lb-ft)
MR (505hp, 471lb-ft)

The engine was a 10:1 383 with Trick Flow heads and the Comp XR288HR (236/242, .520/.540)"

The thing I find most interesting is the 410hp, 500lb/ft from the STOCK TPI. I read the article, it had the stock, 48mm throttle body, no porting or gasket matching whatsoever. Stock TPI, bolted on and making 410hp, and FIVE HUNDRED lb/ft torque. FIVE HUNDRED, and making power all the way up to 6000 rpm! That is amazing, and refutes all the "TPI won't rev", "TPI can't make 400hp", TPI is garbage" crap you see people spewing on this board. Here is a STOCK TPI intake system making over 400 hp, and several modified TPI intake systems making CONSIDERABLY more (Edelbrock Hi-Flo, Extrude Honed, TPIS Big Mouth and AS&M siamesed runners).

Not only that, but the STOCK TPI hit it's HP peak at 4400 rpm, and didn't actually nose over until 6000 rpm! That's a 1600 rpm HP "sweet spot"! Figuring a 2000 rpm shift recovery (manual trans, quick-shifted), that means you could rev to 5500-5600 rpm, shift, and be right in the heart of the torque curve! That thing would pull like a MONSTER!

Now, monte has said several times that, if you put TBI and TPI induction on the same long block, the TBI will outperform the TPI, yet here we have a BONE-STOCK, completely unmodified TPI induction system making more than 400hp, and we've never seen ANY TBI do it.

monte, I'll take that bet ANY day.

Found the actual article:

http://www.compcams.com/Community/Ar...?ID=1737510521

 

http://www.users.bigpond.net.au/ben_...ctorsizing.xls

This link will take you to a calculator that will let you know how much fuel you can get out of 90lb injectors and how much HP that it will support. If you plug in 90 lb injectors at 12 psi, set your duty cycle to 80% (which is low), your BSFC to 50% (which is high) and your new fuel pressure at 28 psi you'll see that there is enough fuel for well over 400 hp. I can also post links to what Ben73 has done with his crossfire vette. What he did proves that two 2" throttle bores with 90lb injectors parked over top of them can run mid to low 12's @ 112mph on street tires even with a horrible intake parked beneath them. Using this RWHP formula you can see he made darn near 400 hp.

HP = (weight*(MPH/234)^3)

350.878 = (3200*(112/234)^3)

Add a conservative 15% and you get
351*1.15=403.51HP

Even with the numbers stacked in your favor he made 400 hp, in reality his motor probably has a BSFC of 40%, you can run duty cycles in the 85% range, run a full 30psi of fuel press, his vette weights more like 3300-3400 with him in it, and it has a drive train loss of 20%. All that works out to more like 447 hp, which is probably closer to the truth.

His data logs prove that 2" throttle bores can support 400 hp, he did it and only pulled just under 1" of vacuum. Holley doesn't even suggest upgrading your carb until you reach 1.5" of vacuum. Your not restricting HP until you're over this threshold. Unlike your TPI example which gave up over 100HP to a better intake, it was restricting HP. You can make 1000 hp with a blown TPI, but that doesn't mean it's not restricting the motor. So there's your prove that there is enough fuel and enough air to make the number, I even showed you an example of some one who has made the number, I could also dig up several big block examples, but for some reason you don't think that's fair. I have a feeling that this explanation isn't going to be good enough for you, and that's why I've been avoiding wasting my breath.

I also don't believe that the aftermarket (I.E. Holley, Jet, ect.) even knows we can tune the ECM. We are such the minority here that very few people even know how to burn chips for the TBI ecm. I bet there are less than 100 people in the world that can tune TBI. That’s why the aftermarket flat refuses to admit that it can be done. Without running higher than accepted fuel pressure and extensive tuning you can't make any more than 275 hp.

So there's an hour of my life wasted rehashing what's been posted on these boards for years.

 

Thanks for all the great input! Honestly if I wanted 400hp there are easier ways to get it than trying to push a system to its limits. Thanks to you all that provided useful suggestions and the rest of you who haphazardy argued over the finer points of FI and what it can or might be able to do or not do sometimes if you are really neat.

Thanks

 

Of course it's not good enough, and you knew that when you "wasted" your time on it. It's not a GM TBI induction system, it's a GM CFI induction system.

And I quote:

Now, unless they made 454 CFIs; unless Edelbrock and Weiand are making carb intakes which can be adapted to CFI, you were saying that A 454 throttle body on a performer RPM or Weiand Stealth intake will have no problem making 400-450 hp on a TBI inducted engine. Those were your words, not mine, and you've said them numerous times. Each time you have, I've challenged you to prove it, you've offered up the CFI as an example, I've said it wouldn't fly and continued to focus on your proving your assertion.

This isn't about your wasting your time on me, it's about your pathological need to get the last word and your absolute refusal to admit you are wrong, or to simply just drop it (as you keep saying you will, but never do), because I won't give you the last word, so you keep coming up with new ways to try and wiggle your way off the dime. It's a joke, and as always, it comes back to a simple issue: You've made an emphatic statement numerous times, attacking me each time I disagree with you. Quite simply; prove it.

Where are the 400hp TBIs?

By the way, am I mistaken in thinking you have a 350 with Vortec heads, a carb intake and a Big Block throttle body? If so, that's the 400 hp setup, isn't it?

 

Jesus hopping Christ, have you even looked at a CFI setup, its just two single bore TB's with an injector on top of each exactly the same setup as a conventional TB. The intake itself has runners that make TPI look good. What I proved is that we have enough air and enough fuel running through a 2" throttle bore and 90lb injector to make the power.

The throttle body doesn't give a crap what size engine is sucking on it. A 400 hp big block is no different than a 400hp small block. A small block might have to turn more RPM's but they are both going to move the same amount of air.

For the third time, your right there are no dyno proven conventional TBI motors on this board that make 400 hp. I never said there were lots of them on this board, I said it was possible. I am not wrong just because some one has not done it before and posted about it. If we all stand around and waited till 10 people did it before us even though we have the data that says it's possible we would never get anywhere.

I have a stock bottom end 350 with 305 heads that has a cam, performer rpm, and full exhaust. I made enough power to push my brick of a car to 98 mph which by the equation I posted above is 275 at the wheels and 316 hp at the crank. I still had tons of room to make power with 70 lb injectors. Show me where a vortec headed 350 made 400 hp. Heck most of the 383's i've seen with vortec heads only make around 390 hp.

When it comes down to it, you have very limited experience with TBI, everything you know is based off of what has been told to you and what you have observed by watching the herd. I know because I've done. When you tune an engine you don't just turn a **** till it sounds good, you get cold hard numbers that tell you how much fuel your injecting and how much more you can inject. You get pressure differentials that tell you if a part is causing a restriction in the air path. You wouldn't understand this because you haven't done it. I'm not the only one that say TBI can make 400 hp, some of the most respected tuners and code writers on this board say it's very possible. Do a search for Grumpy or Rbob, these guys know so much it makes me look like a 3rd grader and they say it's completely doable. Heck Rbob even mentioned he thinks 500hp is possible with the right engine.

They're smart enough to keep the mouth shut when some one like yourself starts tuting off how it ain't possible untill it's proven. You can't argue with that unless it has been proven. Quite frankly it just pisses me off that people like yourself get all pissy because there's not a dyno sheet and video to back it up so I opened my mouth. I'm a thinker, if I see a bucket and it's only half full and it weights 200 lb's then I know it's going to weight 400 lb's when it's full. It's really that simple.

I'm done this time, I'll continue via PM's if you like.

 

You guys need to agree to dissagree. I still maintain that the best numbers (both dyno and track) have yet to be seen with TBI. New stuff is comming to light on a daily basis and little things like EBL get us that much closer. Lets end this one.