TBI Weak Spots
Supreme Member
Joined: Sep 1999
Posts: 2,175
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From: Ewing, NJ
ti si very true that tbi has some parts on it stock that coudl have been done much better. it is eas to see that almost every part of teh engien at one time or anothe rhas been considered a problem buit there are really only a few things that are holing the motor back from big performance.
1. teh cam, our stock cam is a joke. thankfully gm supplied the perfect replacement at a low price in the form of the stock LT1 cam. they are cheap and plentiful, normally ranging between 30 adn 50 bucks used.
2. the stock y-pipe is really lame, it comes togther at a 90degree angle, really more of a t than a y. this can be replaced as a part of swapping on headers or you can have your local exhaust shop make you one fo ra reasonable amount of money, when replaced try to get a pipe that has a 3inch outlet after the y, that will set you up for when you do the exhaust from teh cat back.
3. teh stock intake lacks volume, teh runners are great for velocity, but theplenum is too small to support much power above 4000rpm. this can be replaced with intakes from holley or edelbrock for 200 new or around 125 used. we are doing some experimenting this summer with porting and gasket matchign the stock intake to see what gains that brings. jus twatch the tbi challenge thread to see hwo that works out.
4. swirl port heads. you will hear a lot fo guys bag onteh stock heads really bad. they are an obstruction to making huge numbers, but they are more than capable of handling as much air as the stock throttle body can ever pass. if you decide to step up to a 454tb or holley 670 tb then you will be able to say the heads are a problem, but with the stock tb the heads will work reasonably well.
other than that you can always use a larger tb and a custom ship, but that is true of any stock fuel injected vehicle so i don't think they really count.
your best bet to see what is or isnt a stock design flaw is going to be watching th etbi challenge threads as tehy move along. we are gonna be testing adn tuning everything from dead stock to fully built combos.
later
tim
1. teh cam, our stock cam is a joke. thankfully gm supplied the perfect replacement at a low price in the form of the stock LT1 cam. they are cheap and plentiful, normally ranging between 30 adn 50 bucks used.
2. the stock y-pipe is really lame, it comes togther at a 90degree angle, really more of a t than a y. this can be replaced as a part of swapping on headers or you can have your local exhaust shop make you one fo ra reasonable amount of money, when replaced try to get a pipe that has a 3inch outlet after the y, that will set you up for when you do the exhaust from teh cat back.
3. teh stock intake lacks volume, teh runners are great for velocity, but theplenum is too small to support much power above 4000rpm. this can be replaced with intakes from holley or edelbrock for 200 new or around 125 used. we are doing some experimenting this summer with porting and gasket matchign the stock intake to see what gains that brings. jus twatch the tbi challenge thread to see hwo that works out.
4. swirl port heads. you will hear a lot fo guys bag onteh stock heads really bad. they are an obstruction to making huge numbers, but they are more than capable of handling as much air as the stock throttle body can ever pass. if you decide to step up to a 454tb or holley 670 tb then you will be able to say the heads are a problem, but with the stock tb the heads will work reasonably well.
other than that you can always use a larger tb and a custom ship, but that is true of any stock fuel injected vehicle so i don't think they really count.
your best bet to see what is or isnt a stock design flaw is going to be watching th etbi challenge threads as tehy move along. we are gonna be testing adn tuning everything from dead stock to fully built combos.
later
tim
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