TPI to Carb Help Please!
07-31-2008, 09:13 AM
#21
Le Mans Master
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07-31-2008, 11:43 AM
#22
Pro
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Are you sure you want to switch out the TPI for a carb? How long have you even had this car? Have you considered the pros and cons of the swap itself? And who is going to assist you or are you doing it by yourself? These are some of the things I've noticed since I switched over:
Pros: Higher revving than stock L98 setup, better throttle response, no tuning of computer for new cam/head setups(just carb tweaks), freedom of choice for intakes and carb combinations.
Cons: Hard starts when cold & longer warm-up period, fuel economy dropped about 5-6mpg for a 750cfm compared to stock TB, throttle is a bit funky to get used to(might just be the new cam), no more TC lockup(less MPG again), and what do you do with all the extra wires and TPI setup?
If you're going to keep this car for cruising and slight "auto-x", just keep the TPI and switch to a Superram or a Miniram setup. You may just need to get a better tune and you'll be satisfied. Carbs can make power but you need a good head/intake/cam combo for it. Then there's also the case that you need a LOW profile air cleaner or you have to cut the hood.
Pros: Higher revving than stock L98 setup, better throttle response, no tuning of computer for new cam/head setups(just carb tweaks), freedom of choice for intakes and carb combinations.
Cons: Hard starts when cold & longer warm-up period, fuel economy dropped about 5-6mpg for a 750cfm compared to stock TB, throttle is a bit funky to get used to(might just be the new cam), no more TC lockup(less MPG again), and what do you do with all the extra wires and TPI setup?
If you're going to keep this car for cruising and slight "auto-x", just keep the TPI and switch to a Superram or a Miniram setup. You may just need to get a better tune and you'll be satisfied. Carbs can make power but you need a good head/intake/cam combo for it. Then there's also the case that you need a LOW profile air cleaner or you have to cut the hood.
07-31-2008, 01:56 PM
#23
Burning Brakes
Thread Starter
Are you sure you want to switch out the TPI for a carb? How long have you even had this car? Have you considered the pros and cons of the swap itself? And who is going to assist you or are you doing it by yourself? These are some of the things I've noticed since I switched over:
Pros: Higher revving than stock L98 setup, better throttle response, no tuning of computer for new cam/head setups(just carb tweaks), freedom of choice for intakes and carb combinations.
Cons: Hard starts when cold & longer warm-up period, fuel economy dropped about 5-6mpg for a 750cfm compared to stock TB, throttle is a bit funky to get used to(might just be the new cam), no more TC lockup(less MPG again), and what do you do with all the extra wires and TPI setup?
If you're going to keep this car for cruising and slight "auto-x", just keep the TPI and switch to a Superram or a Miniram setup. You may just need to get a better tune and you'll be satisfied. Carbs can make power but you need a good head/intake/cam combo for it. Then there's also the case that you need a LOW profile air cleaner or you have to cut the hood.
Pros: Higher revving than stock L98 setup, better throttle response, no tuning of computer for new cam/head setups(just carb tweaks), freedom of choice for intakes and carb combinations.
Cons: Hard starts when cold & longer warm-up period, fuel economy dropped about 5-6mpg for a 750cfm compared to stock TB, throttle is a bit funky to get used to(might just be the new cam), no more TC lockup(less MPG again), and what do you do with all the extra wires and TPI setup?
If you're going to keep this car for cruising and slight "auto-x", just keep the TPI and switch to a Superram or a Miniram setup. You may just need to get a better tune and you'll be satisfied. Carbs can make power but you need a good head/intake/cam combo for it. Then there's also the case that you need a LOW profile air cleaner or you have to cut the hood.
Thank you Theseare Very good points. I may give this TPI one more chance If i cant figure out the mystery problem (stumbles on hard accel especially around corners) I may just bite the bullet and do it but for now I am changing the IAC Valve and Maybe the Injectors.
And no this is a little above my skill leval I will have a professional do it.
08-01-2008, 09:14 AM
#26
Burning Brakes
Thread Starter
08-01-2008, 09:34 AM
#27
Safety Car
You can upgrade it to either a later model maf ECM (1227165) as used on the 86-89 cars, or to a speed density setup (1227730) a used on the 90-91 cars (I know '90-91 vettes used a 727 but you would want a '730 to go under the dash) Requires an ECM, some repinning the harness connectors. About 2 hours of work. I can do it now in under 45 mins but I've done about 15 cars for myself and friends. I'm getting good at it 
If you went to the speed density stuff (90-91) you would lose the MPG and range functions of the DIC panel in the dash. I like the speed density stuff better, but in the end it works just as well as MAF for most street applications.
-- Joe
If you went to the speed density stuff (90-91) you would lose the MPG and range functions of the DIC panel in the dash. I like the speed density stuff better, but in the end it works just as well as MAF for most street applications.
-- Joe
08-01-2008, 11:17 AM
#28
Burning Brakes
Thread Starter
You can upgrade it to either a later model maf ECM (1227165) as used on the 86-89 cars, or to a speed density setup (1227730) a used on the 90-91 cars (I know '90-91 vettes used a 727 but you would want a '730 to go under the dash) Requires an ECM, some repinning the harness connectors. About 2 hours of work. I can do it now in under 45 mins but I've done about 15 cars for myself and friends. I'm getting good at it
If you went to the speed density stuff (90-91) you would lose the MPG and range functions of the DIC panel in the dash. I like the speed density stuff better, but in the end it works just as well as MAF for most street applications.
-- Joe
If you went to the speed density stuff (90-91) you would lose the MPG and range functions of the DIC panel in the dash. I like the speed density stuff better, but in the end it works just as well as MAF for most street applications.
-- Joe
So what do I gain by doing this?
08-01-2008, 03:16 PM
#29
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08-01-2008, 03:59 PM
#30
Burning Brakes
Thread Starter
08-01-2008, 05:57 PM
#31
Safety Car
I am capable of doing the conversion for you.... but I wouldn't. I'd advise you to keep your 85 TPI, and even with the older and slower 85 ecm, you can make it do it whatever you want..... I've run the ecm for years and still do, never a problem and its quite forgiving to tell you the truth..... scanning is the toughest due to its slow update, but, as typical with MAF cars, they are forgiving.
Whatever your problems currently are, the solutions are going to be "easy". btw, if you're stumbling coming out of a corner hard, thats probably your fuel pump picking up air for moment or two.... common problem with early C4's..... keep yourself 1/2 tank of gas in it whenever you're out racing, and the problem will more than likely disappear.
Good Luck !!
Whatever your problems currently are, the solutions are going to be "easy". btw, if you're stumbling coming out of a corner hard, thats probably your fuel pump picking up air for moment or two.... common problem with early C4's..... keep yourself 1/2 tank of gas in it whenever you're out racing, and the problem will more than likely disappear.
Good Luck !!
08-01-2008, 08:07 PM
#32
Burning Brakes
Thread Starter
Whatever your problems currently are, the solutions are going to be "easy". btw, if you're stumbling coming out of a corner hard, thats probably your fuel pump picking up air for moment or two.... common problem with early C4's..... keep yourself 1/2 tank of gas in it whenever you're out racing, and the problem will more than likely disappear.
Good Luck !![/QUOTE]
OK well I think i fixed it, it started stumbling more and more, I replaced the TPS and the IAC seems to be a ton better it runns smoother, I may go ahead and do the dist cap and button. Ill keep you updated Auto X is sunday
Good Luck !![/QUOTE]
OK well I think i fixed it, it started stumbling more and more, I replaced the TPS and the IAC seems to be a ton better it runns smoother, I may go ahead and do the dist cap and button. Ill keep you updated Auto X is sunday
08-01-2008, 09:42 PM
#33
Burning Brakes
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08-01-2008, 09:57 PM
#34
Safety Car