OK, lets say I'm building a 500 HP engine. I want to fuel inject it, but don't know what injection system to use. I want cheap. Is there even a TBI system in existance that can feed an engine making that much power? I hear good and bad about TBI. I see TBI on alot of mild engines, but has anyone ever put a TBI based system on a real high performance engine?
Don't say duel TBI because I've had enough headaches with that.

 

LoL, Hmm TBI and headaches seem to go a lot with eachother when it comes to putting them on high performance engines.

I know howell makes some pretty high cfm TB units. I heard there injectors are pretty bad though and have a f-cked up spray pattern. Usually, with high performance engines like that, most people either go carb for cheap performance that works or they go something like MPI or TPI if they want to stay fuel injected, it costs a lot more money though.

Its up to you. Take the chance with the Holley models, or the carb or the other EFI systems. Them are the basics from what I hear, see and read about them. Good luck Duke, and when are u going to Gratiot Ave next? I haven't been down there in awhile. I have been going to Stewart Ave in Flint basically and going to the races there.

------------------
Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
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Yeah, Duke, he's talking about the 900cfm (?) 4bbl Holley unit with the lousy injectors. It can get the job done and I have seen a single unit power a 500+hp blown SBC without problem.

EDIT: How you control the unit it another question. If you want to control it with a 7747-ish, I would go the MPFI conversion route and use a non-injected TB as the air control, but this in not TBI, as you specified, just another route using TBI ECU/harnes/sesnors/logic/PROM.

What happened to your dual TBI???

[This message has been edited by FastBroker (edited May 31, 2001).]

 

http://affordable-efi.com/

call this guy. hes a really nice guy, easy to talk to, maybe he'll explain to you how to use the 4bbl with the stock ecu. which he does. he doesnt like holley or anybody elses ecu, he told me a story about some guys jeep just shutting off everytime he went under high voltage power lines using holleys 950 unit.

anyway, this guy said he would be interested in selling my tbi when i get them built. let him know you are from the tbi board here on thirdgen. if more people call, he'll be happy, and know that we thirdgen tbi'ers are loyal customers.

btw, eric, he said the market for tbi vs mpfi etc. well here is a quote. "you wouldnt beleive how many of these things i sell over the mpfi units, the market is much larger than people think"

thank you, have a nice day

 

Looks like he's using GM ECU's to run MPFI systems. Wonder which injectors he is using and which ECU??? I think I want to use my 7747 to run some MagMar injectors, too, and use the 670TBI for air control... oh, well.

 

I never though of using a 7747 to control a multiport type system. I wouldn't go with a TPI system though, they make torque, but are lousy on the top end, that's why I was thinking of TBI, it has shorter runners for higher RPMs. I'll have to go and check out what manifolds have bosses for fuel injectors and slap a 1000 CFM throttle body on top of it, making a chip for this car is gonna ge one big PITA. Anyway, I'm going to carburate it until I can afford to do something like this, I was actually thinking of saving up fot the Holley multiport system, I've seen this system in person and I know it works real good and is great for fuel milage. Just what I need.

Thanks for the replies everyoe, I'm going to look into the other systems you suggested as well.

Eric, I know what you mean, TBI can be a headache, but it's cheap and reliable, and if done right can make good power, just not with any type of a stock system. I'll be going to Gratiot Friday night if the weather is good. I usually make a few stops at the Dunkin Donuts next to the Marathon station, you know what my car looks like, right?

FastBroker, I built the 427 with the DTBI a long time ago and sold it for a huge profit. It now resides in a 66 Chevelle, if anyone goes to the camaroz28.com M6 event this year your'll see it run, I've ridden in it and it's one bad a$$ machine. I've also burned ovr 30 chips for the DTBI system and it still donesn't work right, that's why I'm staying away from it.

 

Duke, I have pondered using MagMarelli injectors with Weiand's MPFI Vortec manifold, single plane. The manifold is obviously injector-ready and you can get a rail/regulator kit for it, too. Like $255/$175 respectively. Then, bolt on the TB (TONS of them out there!), I'll use a pod-less 670 for now (easy/IAC, etc), and PRAY that the 7747 can run 8 of the Edelbrock ProFlo injectors, which are Mag Marelli's but are BIGGER than the Edelbrock TBI-to-MPFI injectors they use on the truck MPFI conversions with the 7747 ECU. Thoughts? I have heard that the 7747 may or MAY NOT be able to drive these injectors but the Eelbrock conversion allows the 7747 to run the SMALLER MagMArelli injectors... It'd be a nice system, too... Look good, easy to get parts, etc... Plus, tailpipe emissions should be ok, too. Eddie likey.

 

That's a very good idea really. I think the 7747 ECM could work for 8 injectors, it all depends on how much juice each injector uses. I'll look into it, sounds promising.

 

Someone sells a kit to make truck TBI's into multi port systems, I would say there is a way to convert ours as well. On a cavalier board once I saw where a guy took a TBI cavalier and coverted it into multiport, he put the multiport head and injection setup on, but used the tbi computer to control it, it seems to work for him, I think all he did was splice.

 

Edelbrock has been selling a port conversion for TBI trucks for years using the 747, clue #1 is that you need alot less accleration enrichment with a port system then TBI.
Will take some work to get the right chip

 

Gotta love the wet flow systems. No need to "boil" fuel on the valves etc.
Grumpy, I must take a shot at you, never was able to correct you until now. I'm only saying this because I'll never get a chance to correct you in the future but "alot" is spelled "a lot" .
I didn't know that edelbrock was using the 7747 to control their mpfi systems. How do they make them adjustable, or do they provide you with a custom chip?
It's interesting how TPI doesn't have a very good wrap for making horsepower, just torque. The miniram system makes hp and not as much torque on the same engine. The idea is that TPI is "tuned" for the stock oem engines. You can modify them but they are basically all the same. It seems like carb/tbi (share same intake style) make for better hp up top when done right. The best TPI system is on the Ford (yes I said the F word) Taurus SHO. The v6 in the early 90's used 2 different length intake runners. Long tubes were always used for the low end power. After the engine got up over 4000rpm the secondary valves would kick in and the short runners would open from the vacuum change. This helped the engine make some crazy power (reason why stock TBI shouldn't play with SHOs). The chevy TPI setup doesn't have anything that adjusts for the top end, that is why some switch to carb when they go for a crazy engine build (big cam, nice heads, 350+ cubes). Does that all make sense about the tuned port idea?
I think TBI can handle 500hp. You'd want to watch the lobe separation on the cam. Too low and the system won't like you .

------------------
, Jon (350 TBI!)
91 Red My website

[This message has been edited by JPrevost (edited May 31, 2001).]

 

I'd like to try the 112LS roller HotCam with the Vortec heads and that Weiand Intake. It would sure look cool but I'd need to invest in Diacom to get the PROM work done. Probably be big changes needed from where I am know and from what I am used to doing. I'd really like to try this... Heck I could even use the Holley TB, then, cause I wouldn't need the pod/injectors, which I pon't much care for.

[This message has been edited by FastBroker (edited June 01, 2001).]

 

The system that makes tbi multi port uses the stock throttle body and tps, you just remove the injector pods, and I think you do get a custom chip.

Here are links.

http://store.summitracing.com/defaul...rchType%3DBoth

http://www.jegs.com/cgi-bin/ncommerc...ti-Point%20EFI

 

Yes, custom chip, wiring harness that splices into the TBI harnes to run the eight injectors and possibly a HPressure fuel pump as the system runs at 40-50 psi...

 

It all depends on the injectors though. I'd need larger one's to make my goal, and the bigger they get the more juice they need.

I don't think I could ever get a fuel injection system to work with my cam, it's got the 110 degree lobe seperation, I know from experiecne that anything with lower then 112 degrees lobe sepertion is 10X harder to tune with injection, of any type. Hey, I may just keep it carburated until I can afford a good high end fuel injection system. Besides, carbs arn't so bad if you tune them right.

 

I'm familar with this Edelbrock conversion system too. Remember, it's designed for trucks, truck engines arn't designed to work at high RPM's so the injectors don't get firing so quickly that the computer can't supply enough power to keep them all firing perfectly. There are ways around the low injector current though, the LS1 guys running big injectors figured that out a long time ago.

 

I believe that MagMarelli injectors use less current, have less draw (whatever the electrical lingo is) and can be used with a 7747 because of this. I have larger MagMarrellis than the MPFI kit but the are on the Edelbrock ProFlo. They are 28pph, I believe, and the MPI injectors are 19pph???

I want to use these 28pph in MPFI! Can I???

EDIT: Duke, I, too, recently got got a taste of the "dark" side as I installed one of my extra 350cid's, with carb and XE262 cam in the Jeep while I tear apart my other 350. WOW! Don't even ask what happened to my driveshaft. OUCH. Forgot about that motor and it's power... NICE! BUT, had to adjust the carb twice already in one week. Friggin carbs. Friggin driveshafts... Friggin rain...

[This message has been edited by FastBroker (edited June 01, 2001).]

 

I know we're not talking about putting this on a stock engine, but remember our L03's are "truck" engines.

 

the holley 900cfm 4barrel would be great for that. mounts on any square carb flange and will breath plenty for a motor with 500hp. i think the whole set up with a ecm is like $1300. it is fully digital and comes with the lap top interface. it can even do fully electronic spark control with the right set up.
could be pretty sweet.

lata
tim

------------------
91 Camaro RS-LO3,Auto.
14.209@95.46mph
Best 60' 1.917
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My MAFB.ORG Home Page
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electromotive just released new software and hardware to adjust maps on the fly while driving. i would check with them first. 1700 however for the whole system. that doesnt inc the throttle body though.

 

Alot or a lot, BFD, I do that to confuse the really slow folks. BTW, just typing is a shore with all these meds., walking in anothers shoes, yada yada.

Remember the difference in injector firing strategies befor getting too hung up on this.

The TBI fires each injector alternately on each ingnition pulse, so you'll have 1/2 the PW at low rpm, and with many of the larger saturated injectors this will be a problem.
So you might have to run peak+hold injectors. Also remember the peak and hold port injectors are 2.4 ohms as compared to the TBI 1.2 ohms.

You can make about 400 real HP, with a well done GM TBI. 500 real takes a well done multiport, to do easily. 500 could be done with TBI but would take alot of clever work, and research.

 

Why couldn't you use a dual tbi set up with two 350tbi's with a progressive linkage. It would be sweet. Turbo City make a dual setup so you could start there or try to find out how Holley made their four barrel tbi a progressive one. I wish I had the means to do this myself, maybe someone here or in a mag will explore this some day.

Steve

 

holleys is progressive with gears inside the unit i beleive.

 

btw, you can make enough power with a 58mm tbi and some 454 injectors at 15psi.

 

Yeah, I really thing you could make 500hp with the OEM 2" TBI and the FP to the 90pph injectors cranked up a lot. Might not breathe the best and rev up the fastest, but you'd get there.

[This message has been edited by FastBroker (edited June 03, 2001).]

 

i agree.

 

Sacrificing high end power for torque is more like it.

I really think that 500 hp could be done with the 900 CFM throttle body, but you'd need good injecotrs, Holley really has a problem with using a little quality in their injectors. For control, you'd need something that used a laptop computer to adjust it on the go until you got it programmed in right. I think a 900 CFM TBI on a Performer RPM Air Gap manifold would work real well.

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1992 RS
305 TBI, Edelbrock Performer TBI, TPI heads, Open K&N filter, SLP 1 5/8" headers, !cat, custom 3" exhaust, Flowmaster 80 series, MSD 6-AL, MSD Blaster GM coil, Accel Cap and Rotor, Accell 8.8 MM wires, World Class T-5, B&M Ripper Shifter, Nitto 275/50/15 Drag Radials, Radial T/A's up front, LakeWood LCA's, Edelbrock panhard rod, Aluminum driveshaft, LakeWood Drag shocks, IROC rear springs, custom interior, etc.