Vortec 305 TBI *what you need to know* CHP responds!!!!!
TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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In the latest issue of CHP they cover what is needed to create a 305 vortec TBI set-up. It is a very informative article. Since many people here on TGO have accomplished this I want to make a new sticky. Board member Chuck! has had his vortec TBI set-up complete for a few years now and will be giving me a write up soon to what all is involved. There are only a few things in the article that you should not make light of.
-They did not stress how much tuning they needed to do. They spent time on a wide band and had seasoned tuners at turbo city accomplish this task.
-They used modified vortec heads to accept larger cam specs than stock castings allow.
-They do not mention initial timing, base FP, fuel pump type or wide band data.
-They confused me with the numbers they got for the stock chamber sizes on stock LO3 heads.
-They said that this is the first vortec TBI that they had heard of. It is obvious I need to inform them of old news and to visit TGO.
I will leave this thread open so that you can post your qustions and tips. Later on i will compile the posts and make a nice complete sticky that resembles the "new to TBI" thread. I suggest those who are interested to go out and buy this issue.
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Last edited by ShiftyCapone; 04-08-2004 at 01:45 PM.
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I just got done reading this article too and it is EXTREMELY informative! Glad to see this one made into a sticky.
__________________ 1989 Camaro l03 RS
Hothkis springs, KYB struts, polygraphite bushings, and Wonderbar, American Thunder Exhaust, Edelbrock Open Air Element, MSD Cap/Rotor/Wires, AC Delco RapidFires, Spohns LCAs and Panhard Bar, 145 Speedo, TPI Air Intake.
Coming Up: 357 TBI, Hooker headers and Y-Pipe, even more Suspension stuff, and new Rearend. It sucks being 17 and not having a job!
My CarDomain Site
http://www.cardomain.com/memberpage/592863
Hmmm.....very intersting! Shifty, check you PM's....
__________________ "The INFAMOUS Bruce" Gun-Metal Grey 1990 Camaro RS L03' 305 TBI 5 speed One Of Only 2,787 Produced!!
Only mods Flomaster 40series muffler... --1/4mile = 15.3 @ 87.00mph-- See Her In All Her Beauty Here!!
I want some people to chime in with their experiences with this. I know a few of us has done it but most of us have not. I know a lot about this swap but since I have not done it myself I know I will leave things out. I should be getting a detailed write up soon that will be posted. The point of the sticky will be for people to ask questions so that we can clear up the info and push for a tech article. I am afraid if we make it a tech article to soon there may be some confucing parts to it for those who are trying to learn and gain confidense on such a swap.
Well, my setup is almost identical to Chuck's. See the sig. The swap has taken alot of patience. I had some tuning done by tbichips.com but that was over a year ago. I could use more but havent had the time to get into it myself. I've been playing with fp, vacum assisted regulator compared to stock, and stock injectors to 350 injectors. Tuning is a must, my car ran like complete crap until we got it close. I've figured out that a ult. tbi with 350 injectors will do ok but I just recently purchased a holley 670 and the car now idles smoother and pulls extremely hard to 6 grand. I bigger stall is also something that needs to be done, a vortec combo with even a small cam like my LT1 cam needed a stall. Now that it's running so much better I'm thinking about rebuilding the bottom end and going with a larger cam. Maybe ZZ4 or LT4 Hotcam. My last 1/4 mile attempt was last summer so I can't wait to hit the track again, I know it's alot faster than the 14.92 I ran. I really think with the trans go shift kit and spohn sfc's laying in my living room put on, along with a set of drag radials I could pull a 13 sec run. Then if I could get some more detailed tuning in it would be even better.
Originally posted by 89fastlookinRS Well, my setup is almost identical to Chuck's. See the sig. The swap has taken alot of patience. I had some tuning done by tbichips.com but that was over a year ago. I could use more but havent had the time to get into it myself. I've been playing with fp, vacum assisted regulator compared to stock, and stock injectors to 350 injectors. Tuning is a must, my car ran like complete crap until we got it close. I've figured out that a ult. tbi with 350 injectors will do ok but I just recently purchased a holley 670 and the car now idles smoother and pulls extremely hard to 6 grand. I bigger stall is also something that needs to be done, a vortec combo with even a small cam like my LT1 cam needed a stall. Now that it's running so much better I'm thinking about rebuilding the bottom end and going with a larger cam. Maybe ZZ4 or LT4 Hotcam. My last 1/4 mile attempt was last summer so I can't wait to hit the track again, I know it's alot faster than the 14.92 I ran. I really think with the trans go shift kit and spohn sfc's laying in my living room put on, along with a set of drag radials I could pull a 13 sec run. Then if I could get some more detailed tuning in it would be even better.
Hey thanks for the imput. Do you have your vortecs modified? Meaning how much did you have them milled? What thickness head gasket are you running, and are they machined to accpet larger cams? You are dead on with tuning. It is so cool to see a 305 vortec TBI pull to 6200rpm.
I had the heads milled .030. My gasket thickness is .015 I believe. So I may be close 10.1-1 comp ratio. I havent modified the heads for larger lift yet, the LT1 cam seems to be right on the edge of recomended lift for the stock heads. If I do a rebuild then I may go ahead and set it up for high lift. That's were the zz4 or lt4 hot cam comes in. But I'm scared to mess up the tune, it may take alot more to switch cams.
Yea, mine are milled .020 and I have a .015 gasket. .020-.030 seems like the way to go because then they're still very useable on a 350 when inevitibly our 305s blow up.
gunny, i believe that the valve spring pockets have to be machined to a larger size to accept a larger valve spring. LOL, i know what you mean about the info articles on the vortecs... theres so many of them
__________________ 85 Berlinetta Auto, 2.8L MPFI<--w/ overhead console AND flashlight
91 RS 5.0 TBI, Auto, 14x3 open Element K&N, cat removed, Flowmaster 80 series <--- shes about to make her triumphant return to the road
91 Ford F-150, 4.9L I6, 5-speed
"Not enough time, not enough money, and just too many mustangs in the world"
Originally posted by Berlinetta gunny, i believe that the valve spring pockets have to be machined to a larger size to accept a larger valve spring. LOL, i know what you mean about the info articles on the vortecs... theres so many of them
To run better stock size springs.... 1.25" springs fit the stock heads fine. Over .500 lift.... some say 1.25" diameter springs work. Some don't. I will be running .510/.544 lift so I'm going with some 1.440 diameter Comp 987's that I just purchased. And yes for those you will have to machine the spring seat larger.
You know in that article they are claiming that they didnt tune the chip at all. Hmmm..... The owner of the car also claimed that the motor was pulling real hard and they didnt list any complaints. So maybe if you just pick the right combo you dont have to worry that much about tuning. Or maybe they would have picked a hole bunch more power after tuning. But the fact that they picked up 85 hp and 66 ft lbs of tq is awesome.
Originally posted by IROCaholic You know in that article they are claiming that they didnt tune the chip at all. Hmmm..... The owner of the car also claimed that the motor was pulling real hard and they didnt list any complaints. So maybe if you just pick the right combo you dont have to worry that much about tuning. Or maybe they would have picked a hole bunch more power after tuning. But the fact that they picked up 85 hp and 66 ft lbs of tq is awesome.
Actually they did tune it. They said they used Turbo Cities in house dyno and wide band. They tuned the hell out of it but they didn't stress how much tuning they really had to do.
well heres the quote that made me think other wise "But the simple fact of the matter is, we ran out of time, hence part 1. Our creation would have to make its first dyno run with the stock throttle body(one thats been blue printed, but one that still only flows approximately 520 cfm) and with the factory computer programing to boot." They were saying that in part 2 they will test it with the chip tuning and throttle body but they ran out of time in this segmant so I dont think they did tune it. But I could just be reading it wrong.
Originally posted by IROCaholic well heres the quote that made me think other wise "But the simple fact of the matter is, we ran out of time, hence part 1. Our creation would have to make its first dyno run with the stock throttle body(one thats been blue printed, but one that still only flows approximately 520 cfm) and with the factory computer programing to boot." They were saying that in part 2 they will test it with the chip tuning and throttle body but they ran out of time in this segmant so I dont think they did tune it. But I could just be reading it wrong.
You are reading it wrong. Your quote is refering to the additional tuning they will need after they install the larger TBI unit. That car would not even idle right with the stock tune. Read the part that is highlighted in the yellow/orange part. But I am glad you pointed that out because that is what I find faulty with their articel. They failed to stress how much tuning they really needed. They used an experienced tuner with a wide band 02. The average reader will not pick up on that. Us TBI nazis will
Last edited by ShiftyCapone; 04-13-2004 at 12:02 AM.
Your talking about the part where they listed the flow data right? For some reason it still looks to me as if they are saying that miller guy is going to tune it in the next segmant,but hey I am certainly no tbi nazi, in fact I will be ditching my tbi setup as soon as I get my new motor in the car and setup because I really dont want to waste my time doing the tuning. I do have to give it up to you TBI Nazis you are very patient people I will never be patient enought to tune a tbi chip.
Originally posted by IROCaholic Your talking about the part where they listed the flow data right? For some reason it still looks to me as if they are saying that miller guy is going to tune it in the next segmant,but hey I am certainly no tbi nazi, in fact I will be ditching my tbi setup as soon as I get my new motor in the car and setup because I really dont want to waste my time doing the tuning. I do have to give it up to you TBI Nazis you are very patient people I will never be patient enought to tune a tbi chip.
Yea you have to read in between the lines. That is one of the beefs I have with the artilce because they do not stress that. They say "This bumpstick will also work with Turbo City founder Tom Miller's computer reprogramming." They make is sound like he is going to do it later. But trust me you will not gain 80+ at the wheels with these cars unless you burn a new chip.
at least turbocity will have a chip for those mods and would give alot of people a nice starting point in tuning, but im sure they would charge a **** load of money for the bin, we should all donate a dollar, buy a chip and distribute the bin, screw the legal system. .
did you guys see the previous issue where they added 3.42s and posi to the camaro, they did gain nearly 3 tenths but are still only running a 16.565@82MPH. I dont understand, it seems like every thirdgen they test runs crappy times.
did you guys see the previous issue where they added 3.42s and posi to the camaro, they did gain nearly 3 tenths but are still only running a 16.565@82MPH. I dont understand, it seems like every thirdgen they test runs crappy times.
I was thinking the same exact thing. However that car was bone stock down to the paper element. However it should still have been into the 15's if you ask me.
Originally posted by vjo90RS8 at least turbocity will have a chip for those mods and would give alot of people a nice starting point in tuning, but im sure they would charge a **** load of money for the bin, we should all donate a dollar, buy a chip and distribute the bin, screw the legal system. .
did you guys see the previous issue where they added 3.42s and posi to the camaro, they did gain nearly 3 tenths but are still only running a 16.565@82MPH. I dont understand, it seems like every thirdgen they test runs crappy times.
actually, my car, with similar mods to theirs when they put the gears in, runs about the same. when i went to a 3.42 posi from a 3.08 pegleg, though, i picked up 6 tenths, not 3 (16.50 to 15.90). with their stiffer suspension, though, they're probably not hooking up as well as they might.
i'm disappointed because they're making the same mistake i made when i got started ... they're bolting on parts and blowing the chip tuning off. i've said it before; when i got my car, i understood headers, ignition, gears, etc., so i did them. i didn't understand chip tuning, so i avoided it at all costs.
i believe there's a bigger reason why they're doing it this way, though ..... no money in it for them. look at all the articles the various magazines have done on the obd2 tuners like hypertech, jet, granatelli, etc. over and over they plug them into a stock camaro or mustang and show the before and after. since no potential advertiser offers a product or service that allows that kind of tuning on a third gen, they blow it off.
gm high tech performance recently put an ed wright chip in their blue thunder project and had all sorts of problems ... had to send it back and forth several times before it would run anywhere near right. anyone who is marketing chips for our cars is going to avoid having their products put under a microscope in an article like this like the plague ... they don't want it to become obvious how far off the mark their "off the shelf" chips are.
while i'm glad to see any third gen tbi projects in a magazine, it's too bad they didn't start datalogging and chip tuning right away.
__________________ 1989 WS6 Formula Firebird T-Tops
L03 305 TBI 5 speed
SLP takeoff 3.42 posi rear (was 3:08 open)
Ultimate TBI mods
1/4" injector pod spacer
MSD 6A ignition (switched back to stock, AC/Delco distributor, coil and wires and picked up 3hp!)
'84 Trans Am functional cowl induction with K&N element
SLP 1 3/4" shorties w/air
Dual 2 1/2" converters
Custom 3" cat(s) back
Flowmaster 40 series muffler
Spohn weld-in subframe connectors
Lakewood control arms
Hotchkiss adjustable panhard bar
KYB shocks and struts
170 rwhp, 263lbs. ft. torque
best 1/4 mile: 15.62 @87 mph
Originally posted by IROCaholic Your talking about the part where they listed the flow data right? For some reason it still looks to me as if they are saying that miller guy is going to tune it in the next segmant,but hey I am certainly no tbi nazi, in fact I will be ditching my tbi setup as soon as I get my new motor in the car and setup because I really dont want to waste my time doing the tuning. I do have to give it up to you TBI Nazis you are very patient people I will never be patient enought to tune a tbi chip.
which induction system will you be using then that doesnt require tuning? i want that system!
LT4 cam (basically an LT1 cam with a bit more duration)
Edelbrock Performer RPM Air Gap
Vortec L31 heads (906 casting) with new springs
Holley 670cfm currently not installed on the car due to my hatred of the linkage.
Just a few comments. I flipped through the article quickly - a buddie's rag, I'd never buy CHP - and noticed a few glaring issues with that 305 buildup. First on my mind was the cam they used. If I recall correctly, it had around .520 lift on both valves with a fair amount of duration and was a totally custom grind - IF i'm right about that, doesn't that make this whole enterprise a one-off? Also, I recall that the money put into this monster was horrific - something around $3000 (right?) - for around $3000 someone could have a 350 crate motor, or could build their own 400hp 350 in their basement. Sure, they tuned the hell out of the car - but I really wonder how driveable it was afterwards, whether there were any flat spots in the power-band or not - and again, how would that be reflected in the real world since most people can't tune their own stuff, or don't want to pay through the nose to have others do it. Lastly, in talking about the TBI they said the STOCK unit flowed around 520cfm having been seriously modified, again - I question this. Before its been brought up that a 2-bbl TBI or carb is flowed at a higher presure than a 4-bbl unit. Thus, even a performance unit, like say the holley 670 cfm TBI, is really only around 500cfm when you do the math, so I have no clue where they're claiming 520cfm of flow on a stock unit w/the same overall bore size...
I'm not bashing TBI - its an awesome low-tech system that can be really reliable and offer some performance, but for someone who isn't a dedicated tuner - it isn't the way to make horsepower. A 4-bbl TBI that can flow is one thing, but the units we're talking about here just plain don't. My 350's power-band is set to peak at 6,000 RPM - with the holley on top, it peaked at 4,500 - why? Because it doesn't flow enough (so i believe). Also, you'll notice CHP had no dyno-charts (where was THEIR new peak?) or even RWHP numbers. They said they gained 85hp or whatever, but WHERE?? It seems to me they're just trying to appease a crowd by throwing crap at them. I'd rather see a REAL TBI buildup done with a basis in reality.
Not to side with CHP but in all fareness they got their cfm #'s form Turbo City, I think when they finish the story in their next issue they will include the dyno graphs and track times. I also agree that for the money a 350ci/350hp would be easy to put to gether. I know I don't have that much invested in my engine and should be in the 370 to 400hp catagory with a good fourbarrel carb.
Steve
__________________ To be added to my 91RS this summer: 350, pocket ported vortec heads w/ 9.4cr, combustion chambers and pistons crowns polished and coated w/techline thermal barrier coating, LT4 Hot Cam Kit, RPM Air Gap, 454TB w/90lb injectors, Headman shortys, 3" catback and a 3.42 posi.
They mentioned in the article that they would probably get some mail from peolpe saying they were stupid, when they could have purchased a 350 for the same price, but their response was (which I agree with), "Well that's not really the point now is it?"
I think they understated the importance of that cam and really dove off the deep end with how much they had to have the vortec heads modified, but I won't judge CHP until the next issue comes out.
P.S.- Those numbers they gave were dynod numbers with a 22% correction for the 700R4.
I spent, "to get the car running" about 1300 dollars initially. I got my heads from sdpc and the intake also. The rest was from jegs. www.sdpc2000.com is a really good site to order all this from. They have the exact gasket kit for vortec's and the 2 different bolt kits as well. They also offer the better version of the vortecs with the z28 springs that will allow .550 lift. Stock they say is .450, which is what I got, I wish I went with the other ones though that way it would be ready for a bigger cam.
i just read the article, and a couple of things stick out:
1. most of the "serious" money they spent was on labor to make the egr work and stay smog legal. if that weren't an issue, it would've been a lot cheaper. shifty capone, i believe, is running the same intake and heads. his solution was to take the output of one of the a.i.r. tubes on his headers to plumb exhaust gasses to the egr valve. either that didn't occur to them, or it wouldn't pass the tough california visual inspection, i guess. regardless, i believe that gmpp tbi intake is the only way to make vortecs and egr work on a tbi car.
2. the porting on those vortecs provided some amazing numbers! it's too bad they didn't detail what they did to them ... the mid flow and .500 numbers are in the afr 190 zone.
3. it's obvious the people doing the work don't know anything about tbi, as made evident when they say superior automotive wanted more duration than the .210/.214 duration @ 0.050 cam they went with.
4. they made the same mistake i and so many others make of leaving the chip tuning for last. i wish they'd done it earlier in the game.
5. that engine should be making more power with those heads. 15 years ago, hot rod make 300 crank horsepower with a 305 with l98 aluminum heads and the stock throttle body (with 350 injectors). on the other hand, they'd done no chip burning yet, so i guess the jury's out till next month on that. at the end of the article, they say they had to do the first dyno run with the stock chip and throttle body. if that's the case, the power gains they discuss are amazing, as is their claim of great driveability. i wonder how they did that with the stock chip?
Originally posted by seanof30306 i just read the article, and a couple of things stick out:
1. most of the "serious" money they spent was on labor to make the egr work and stay smog legal. if that weren't an issue, it would've been a lot cheaper. shifty capone, i believe, is running the same intake and heads. his solution was to take the output of one of the a.i.r. tubes on his headers to plumb exhaust gasses to the egr valve. either that didn't occur to them, or it wouldn't pass the tough california visual inspection, i guess. regardless, i believe that gmpp tbi intake is the only way to make vortecs and egr work on a tbi car.
Actually my buddy is running this set-up and not me. The vortec routing was done by someone else. Most people just delete EGR out of the RPOM when they go this route. It will be interesting to see their results when they are done. I am excited.
Originally posted by seanof30306 i just read the article, and a couple of things stick out:
2. the porting on those vortecs provided some amazing numbers! it's too bad they didn't detail what they did to them ... the mid flow and .500 numbers are in the afr 190 zone.
I think you have missed something here, the flow #'s should be in the 230 to 240 range.
Not to be picky or anything but thats the facts.
I'm also amazed at how well the car ran on the stock chip, they didn't seem to have any problems after the swap like everyone else does. I wonder if it had anything to do with bringing the compression back up to where the factory claims all L03 are supossed to be.
You really have to read between the lines in that article. They did a tremendous amount of tuning and will do more when they put the l;arger TBI unit on. I have witnessed the tuning of a vortec 305 TBI swap and it is a pain. That car would have run much much slower in the 1/4 without tuning. A stock LO3 will beat a vortec 305 TBI with a stock tune.
Shifty, what lines were you reading between. I just reread the article and couldn't come to any conclusion that they did anything to the chip unless it had been previously changed before this edition of L03 Blues. Did you also notice that they said the stock tbi flowed 520 cfm (can you dig it). If thats true the the 454tb ought to flow a good 750cfm (I could dig that).
Originally posted by steve8586iroc Shifty, what lines were you reading between. I just reread the article and couldn't come to any conclusion that they did anything to the chip unless it had been previously changed before this edition of L03 Blues. Did you also notice that they said the stock tbi flowed 520 cfm (can you dig it). If thats true the the 454tb ought to flow a good 750cfm (I could dig that).
Steve
Yea it is really unclear. That is one of the few problems I have with this article. Thier cfm numbers were awesome, but cfm ratings for TBI are much different than carb. Anyways, in the orange print they talk about the wideband and dyno tuning by turbo cities elite tuner. They say that CHP wanted to go bigger on the cam but turbo city held them back for tuning sake. That implies that they tuned it. There is no way they will gain 80+ hp with a stock tune. These cars are cry babies with the stock tune and even headers, no less heads and cam.
Originally posted by steve8586iroc Shifty, put your glasses back on and read the article again. I couldn't find any referance to a wideband anywhere.
Steve
You know what......I think you are right. I am really confused now. I re-read it for the millionth time with an open mind. Here is what confuses me. They say "This bumpstick will also work well with Turbo City's founder Tom Miller's computer programming" They go on to say that they blueprinted this cam to keep it within the air fuel tables.
Then they say about how it was hard to put it all together and when they were done "we had to make our fisrt dyno run with the stock compter programming"
For some reason I cannot find the part about the wide band. There must be a gas leak in my office???? I FOUND IT!!!!
Ok here is why I got the dyno tune part. They are going to do it but have not yet.
They say "Also note the bung welded in by Superior; this allows an air/fuel ratio monitor to be hooked up during suno tuning" So they are going to use a wide band but have not yet.
Even still I have a tough time swalloing those numbers with a stock tune. I only say that because of my buddies ride. It ran a full second slower with the stock tune then when he was stock.
Last edited by ShiftyCapone; 04-22-2004 at 12:04 AM.
I would also like to know how they got those numbers under the stock computer. I knew the Vortecs worked well with the engine, but not that well.
I think there's more to that cam than they are leading on. What were the specs on it, or did they even give it? I left the rag in my car and I don't feel like walking out to get it.
Originally posted by ShiftyCapone You know what......I think you are right. I am really confused now. I re-read it for the millionth time with an open mind. Here is what confuses me. They say "This bumpstick will also work well with Turbo City's founder Tom Miller's computer programming" They go on to say that they blueprinted this cam to keep it within the air fuel tables.
Then they say about how it was hard to put it all together and when they were done "we had to make our fisrt dyno run with the stock compter programming"
For some reason I cannot find the part about the wide band. There must be a gas leak in my office???? I FOUND IT!!!!
Ok here is why I got the dyno tune part. They are going to do it but have not yet.
They say [i]"Also note the bung welded in by Superior; this allows an air/fuel ratio monitor to be hooked up during suno tuning" So they are going to use a wide band but have not yet.
Even still I have a tough time swalloing those numbers with a stock tune. I only say that because of my buddies ride. It ran a full second slower with the stock tune then when he was stock.
HA, so I was right all along. In your face shifty. JK
Yea you guys are right. You got me. Anyways, as the old saying goes, I am not buying their brand. There is just no way. Even adding headers to these cars throws the tune off. Man this is buggin me. ha, calm down. Magazines always make it look so easy. I am writing them an email. I have a lot of tech questions
.
:rockon: 
