I just swapped in a 355 with a cam from a 87 iroc, L98 heads, edelbrock cat back with no cat, bosch plugs and wires, and an open element air cleaner. I'm running the gm tbi from my 305 with gm 350 injectors, esc module, and a motervation "strip" chip for an 89 caprice. My car runs fine, no problems what so ever...the performance is just kind of lacking...and that's coming from someone who drove a very hurt 305 for a year. I mean it's faster that the 305....but it's still not very impressive to me. The mph seel to climb fast but it just doesn't but much "put you in the seat" to it...not much at all. I was just wondering if the bigger fuel pump or bigger regulator is needed right now seeing as how I don't really have anything special done to my engine. Any suggestion on what could be going on?

 

come on I know someone can help

 

The TBI is your problem, did you reuse the exhaust mainfolds from the 305 as well? If so then the engine's not going to perform alot hotter than your old 305. Get headers, Carb it, or get into chip burning and program your own prom. There's a TON of info on members who've gotten good performance out of the TBI's. I believe alot of them use the GM factory 454 TB.

 

Id bet its likely too rich with too little timing. The stock TBI doesnt help, either.

Adding timing, leaning out the fueling, and tuning the VE table would probably do wonders for the performance. Even with the 2.73's, it still should pull hard in first and second with that cam and heads.

Another tip: If you havnt done so already, get subframe connectors NOW if you have t-tops and you dont want to tear up the car.

 

I agree with the comment on sub frame connectors. I had an old L03 when I purchased my camaro. Even with 170HP on a good day, it would twist very bad when you take off hard and when it shifted to 2nd gear. I had Hotchkis SFC's installed and the car drove 100% better. It seemed faster (even thought it was minimal) and handles awesome. No more twisting and lost power through distortion. Put the power on the road not in your back seat.

 

Actually I believe Dimented is talking more along the lines of someone ending up driving 1/2 of a Camaro. I know from his PM's that the torque of his 350 was literally bending the rear portion of his car like a squeezing a soda can.

 

This isn't a blatant thread hijack but I have a question; I've heard before that all Camaros built from 90 on were built on the convertible frame. I noticed the undercarriage of an 86 looks completely different from my 91. I also noticed that my friends 89 formula had stress cracks on the roof in the back corners of the windows, mine never got these and I launched my car harder than his. This pertains to Boogie because because his car's a later model like mine.

 

IIRC, the convertables where done out of house, at least early on, and got boxed re-enforcing SFCs. What do you see behind the rocker panels? If theres only the pinch weld there, then there probably isnt any re-enforcement. Without it, you can literally see how much it twists under power. The hood will be at an angle while the rear hatch is still level. My brothers old 3rd gen with a TPI'd 400 would go down the road on three wheels under power.

 

There's no form of subframe connector under the car (at least there wasn't before). I put in 2 peices of straight tube that went in almost perfectly, welded 1 along side the box for the LCA and the other end sat neatly in a U shape on the front subframe. The actual body itself looked different than the 86 Z8 from underneath, I should've taken pictures while I was under them.

 

So how do I tell if it's running rich...and what's the ve table?

 

Also, how much timing should I give it?

 

The VE table is one of the parts in your PROM/ECM that deals with spark and fuel flow, or something like that. I'm not real sure on the PROM tuning thing yet either...

If you eninge is running really rich you should be able to smell it, and/or see if its rich. Your exhuast with be blackish smoke out of the pipes.

As for timing, best thing to do is adjust to a certain point and drive it. See how it performs and then try something else. When you're at idle is what you maybe concerned with, depending on your driving habits. Starting the engine can become an issue also if the you have "too much" timing.

 

ok thanks, but I can't smell the gas and there's no blackish smoke....some white smoke at first start up though. The engine has just over 1k miles on it, changed the oil today but didn't check if it still did it or not.
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btw I figured maybe it was running a little lean because of the stock 305 fuel pump and regulator. I don't know how to tell though.

 

Did you do the free mods to the TBI and make the regulator adjustable?

 

Nah I didn't see that one. Guess I'll look again.

 

Ok I just found that...I just have a feeling I'd hurt it more than help it.

 

Not meaning to steal a thread, but what exactly are you meaning by this, is there an adjustment somewhere?
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ah this is where i was like 4 yrs ago..

VE table is the table within your cars computer that handles fueling. Just picture a spreadsheet with a bunch of numbers on it, you need more fuel at such and such rpm? you increase the number on the chart, this is an extremely simplified explanation. VE stands for Volumetric Efficiency but don't worry bout that.

Subframe connecters are a must, i have a freshly painted hardtop with a stock lo3 and its showing stress cracks allready.

Playing with your timing at the distributor on these cars is a spit in the wind, it can help a lil but you can only advance it to like 8* on a stock motor.

the TBI is not your problem as someone said. TBI has a learning curve a mile high but the payoff is at better performance then a carb by far. Also IIRC the same tbi unit is used on the L03 and L05. Stick with that TBI bud, read the thread "come in for a free tune!"

Now yes, your fuel pump is most likely hurting you. they might work well for shooting spit wads but high performance they are not. Walbro 255 is what im dropping in my tank in the spring, you won't find a more recomended pump.
ditto to the exhaust side of things, curly straws flow better then the stock manifold/y pipe,
the fuel pressure regulator is a little cup on the backside of the throttle body under the injector tower. it houses a spring and gasket that regulates the pressure, with a lil work it can be made adjustable via an allen screw. no biggie.

ill tell you before anyone else does, read the stickies, they are the treasure trove of tuning. This lil forum has been mentioned in magazines and has recently gone international due to the excellent efforts of the crew round here, give em a break and read the stickies, saves them some time.

welcome to TBI!

 

after looking around I've read that I should make the fpr adjustable and I've read not to make it adjustable, just mess with the ve table instead. I'm not sure which is right. Anybody know the real answer?

 

the answer is both.
the ve table controls fueling however a combination of injector sizing and fuel pressure controlls how much fuel it has to play with.

you can increase the numbers in the ve table as much as you want but if you dont have enough fuel you simply cannot go any farther untill you increase fuel pressure and or injector size. there is such as thing as too much fuel pressure and also injectors that are too big, you have to balance all of these elements to achieve perfect fueling.
as far as regulators go i think an external unit like an aeromotive combined with a GM 30 psi regulator for the injector pod will give most people enough adjustability for street performance. tottaly ripped this idea from a STICKY at the top of the page.