I just got me a 1990 Swb chevy truck to play with,trying to decide which motor route I'm taking.So how much horsepower have you been able to support with a throttle body injection?the truck has a 350 in it and I have a complete running 454 engine with tbi also. What I'm wondering is if I build the 350 up if I run the throttle body off the big block what would be needed To tune it?
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Help Support Hardline Crawlers :
How much power have you been able to run with tbi
- Thread starter Elliott
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TBItoy
Well-Known Member
I used to mess with tbi stuff some, IMO, it's old outdated technology, and you'll spend the same amount of money on a tbi setup with mediocre results that you could easily and cheaply outperform with a carbureted setup, or an LS style late model swap.
There is a lot of info on tbi setup and tuning on thirdgen.org, it's a third gen camaro/firebird site.
There is a lot of info on tbi setup and tuning on thirdgen.org, it's a third gen camaro/firebird site.
doctordick
Classic American Iron, son.
Run the 350 injectors in the 454 throttle body and either make or buy an adjustable pressure regulator. You should be able to support over 400hp up to around 6000 rpm. No ECM tuning required unless you put a long duration cam in it. Thirdgen.org has some really good info. 
TBItoy
Well-Known Member
doctordick said:Run the 350 injectors in the 454 throttle body and either make or buy an adjustable pressure regulator. You should be able to support over 400hp up to around 6000 rpm. No ECM tuning required unless you put a long duration cam in it. Thirdgen.org has some really good info.
This is true, the tbi setup doesn't really "know" or care how big the engine is, or how much air is going into it, you just have to adjust fuel pressure and injector size according to your motors fuel needs, a lot like resetting a carb... Tune by plug color, or install a wideband o2 and display.
I had a .060 over 305 with ported stock heads some brand of low end torque (isky?) cam and a Holley tbi unit. It ran pretty good.
The biggest problem is not being able to run big cams without tuning, and the obd1 stuff isn't exactly tuner friendly, and the stock tbi heads are Shitty! And the reason for swapping good high flowing heads is to take advantage of a big cam....
A basic stock LS truck motor 6.0 with some tuning software (hp tuners/EfiLive) and a wideband o2, and you can slap a retarded big cam and valve spring package in it and make some fun street hp for about the same "investment"
TBItoy
Well-Known Member
Elliott said:
454 tb should work fine
That 11:1 cr helps with torque
That combo will run pretty good, 320-340hp or so probably. And not cost much $
I kinda thought you were wanting 400+ for a street truck.
Fire Freak
Well-Known Member
i m not 100% certain but i dont think your throttle body intake will fit the vortec headsElliott said:
TBItoy
Well-Known Member
:
Correct. have to buy a conversion manifold.
Fire Freak said:
Correct. have to buy a conversion manifold.
mrdrinksalil
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I converted my older SBC to GM TBI. The only real advantage is that it's better than anyones carb on the trail and it's cheap. However, it's an extremely primitive setup. Uses MAP, Throttle position, o2 and RPM to calculate fuel. The big downfall is how slow the computer processes all this information and makes adjustments. They are VERY slow. Regardless of what everyone tells you, you WILL need to have a custom chip burned to have it run correctly if you're going to push its limits. Lots of good info on the binderplanet forums. The limiting factor is how much air you can push through the larger 454 throttle body. You can raise fuel pressure and tuning to add fuel all day long, but only so much air through the throttle body. You can always run two throttle bodies and get more air in that way, but by the time you spend for an intake you'd be close to $$ for a FAST setup or similar.
Go read the info in the "FAQ's in the Binderplant, Injection Section" forum. That will give you all you need to know about GM TBI. I may be interested in selling my chip burning hardware and tuning stuff if you're really interested.
Go read the info in the "FAQ's in the Binderplant, Injection Section" forum. That will give you all you need to know about GM TBI. I may be interested in selling my chip burning hardware and tuning stuff if you're really interested.
doctordick
Classic American Iron, son.
454 TB is rated 670 CFM, That should be plenty for a street motor. You can use anyone's carb size calculator to find out for sure. Not too sure if you'll have enough vacuum signal from a 270 degree cam. I run a 268 with a stock chip, but I have a Howell harness that eliminates all of the TBI ignition system (there's a little circuit board in the harness which is an A-D converter to provide ignition reference signal to the ECM) and has a different MAP sensor, I assume to compensate for the cam.
blacksheep10
XBJRA champ/ 555 and team Nasty codriver
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I had a BBC TB with SB injectors on a 7116 4 barrel manifold adapted to the 3 bolt TBI on vortec long block in my blacksheep. It always did really well. I didn't play with cams, but if felt as good or better than when I had the qjet on the exact same engine (hence the intake).
crawlin85cj
Barco Motorsports
Howell is probably the best out there for TBI info and tuning. I ran it in my Jeep before yanking it in favor of LS power. The motor ran good but I would have been far better off going with a 5.3 in the beginning.
muddinmetal
Guntersville, AL
I ran a .30 over 454 with one of these http://marine-performance-parts.com/cfmtechportedthrottlebodyforgmtbi74l.aspx which is a direct bolt on with the factory tbi adapter to a 4 bolt carburated intake (I choose a weiand action plus) 7.68 to 1 (!) compression, headers, and a jet adjustable fpr in a 1990 454ss. Made a pathetic 262 rwhp, up from the factory 207. But that is all I had done to it at the time. Motor ran great until I added a small 262 crane cam. DO NOT cam a tbi motor until you visit http://www.tbichips.com/. I'd say 325 rwhp is the max, without nitrous, for it to still act right though...
Big Block tube buggy
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i have a 454 .30over 11 to 1 cr 280 duration hydraulic roller cam ported and polished 427 closed chamber heads not sure but in the 500hp range, has a 900 holley tbi howell harness gm ecm with a custom burned chip it runs good idle to full bore. If I was running on the street with the 350 a 650cfm holley carb (dual line mechanical secondary 4150 base not a spreadbore) lot cheaper and easy to tune. 
tommyswheelin
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Just put propane on it. I know how much u love propane
Fire Freak
Well-Known Member
I had a 89 chevy with 9 in lift and 40s and an older 4bolt short block with 30 over flat tops with a small comp cam it had throttle body heads and intake with a throttle body spacer 2 in. spacer i Had to run mufflers to give back presure. No straight pipes. It idled way to high. But it could roast the 40s. A guy that built race cars said it sounded like 400 hp but that was just a guess. But it would turn a ten bolt into a pretzel at will.
Bronco Buster
Well-Known Member
That thing would turn a 10 bolt into a pretzel with 38 Cepeks and stock gears.
