TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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Be careful playing with boost on iron heads. They detonate easier than alluminum.
Also if your going to change the engine at the same time as adding the supercharger, you are MUCH better off building a FORGED low compression bottom end and then running more boost on the supercharger thus making big power.
You may get better answers in the power adder section also.
There is somone on here, dang i can't remember who, who had an ATI procharger on a carb'd engine. I've always wondered if the adapter neck for it would fit a TBI motor.
[size=3][color=red]vortechsuperchargers makes a kit for the 5.7 pick up truck, they say it will fit onthe stock tbi but they are not sure about the holley, im still waiting for a reply from holley if it would fit
91 firebird 305
85 firebird 305 carb, for sale runs needs work selling cheap
Originally posted by JPrevost It fits on the holley. It's just a carb bonnet. You'll need to make room for the kit and do some custom fabrication but it isn't anything really hard.
well they say 85 horsepwer and 100 more pounds of tork, on the a stock pick up truck, i want to know what it will do with the holley 670 cfm, and if i build a low compression motor for it.
I measured a 65% hp increase on my stock Cross-Fire with the Vortech V1 A-Trim supercharger (The least effichent vortech of them all). I did not use any intercooler.
RW numbers went from 186hp @ 4200rpm to 308hp @ 4900rpm.
I made two runs without the supercharger and two with, all four runs within 10 minutes.
I must say that supercharging the TBI worked great for me ...
Yes, The supercharger was the only variable. I only removed the belt that drives the supercharger. That is all.
At 5000 rpm I have 10psi boost (measured in the plenum after the TBI's ). I know that it is a lot, but it is easy to build boost on a restrictive intake. On a free-flowing intake the engine will get a lot more air at lower boost.
[SIZE=4o man is that awsome i want to do somethign like that with my firebird that would be so kool then i would have the most pimped out tbi car here lol
I put a 7psi Paxton setup on my 92 Formula about 3 years ago.
With just Edelbrock TES headers, 2 1/2" flowmaster and the Paxton at 5psi (belt not fully tightened), I dynoed 201rwhp @ 4150 rpm and 275rwtq @ 3075 rpm.
That was with 0 tuning (stock timing even). 100% stock engine, including TBI (no ultimate TBI mods) stock fuel pressure, EVERYTHING! Stock transmission, stock open 2.73 rear.....you get the point. At this stage I ran a best of 15.22 @ 92.56 MPH with a 2.418 60ft time.
I bumped the timing up to 6*btdc, added the SLP take-off posi with 3.42's, Spohn LCA's with lowering brackets,and some Nitto Drag Radials and went 14.42 @ 95.96 MPH with a 1.98 60ft time. NOTHING else was changed at that point. (Stock I ran 16.29 @ 84.29 mph with a 2.443 60ft)
Since then I've changed to a high flow 3" cat, 3" Edelbrock cat-back, ultimate TBI mods, and an LT1 cam. But my transmission is on it's way out so I haven't brought it to the track yet since the changes. Plus I want heads, intake, and 1.6 roller rockers, so I'll need some tuning too, in addition to the trans rebuild with 2800 rpm stall converter. And a Ram Air II hood, because I've already put "pimple" in my hood from my lack of hood clearence.
With all the changes in that last paragraph I'm hoping to dip into the 12's.
Everything except the cam will be transfered to a 350 someday, so we'll see how that goes.
Here's a pic of how it looked back in the summer of 2000
Last edited by Blown 305 TBI; 03-08-2002 at 10:20 PM.
Any questions you have I'll be more than happy to try and answer for you.
NJ, it's a kit that Paxton used to make for our cars. (as far as I know, mine was the last TBI f-body kit Paxton ever made) It's basically the truck kit with both sets of instuctions (f-body and truck) so you can see how to move the cruise control and where to put the tubing for the air intake, and all that fun stuff. It came with an upgraded fuel pump, but of course they didn't bother to tell me the specs on it. But the bracket is quite beefy.