To chip or not to chip?
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
To chip or not to chip?
Hello! I have an 85 vette with a worn out motor. I have a new motor ready to go in, nothing crazy sbc 355 .30 over, 2.02/1.60 heads decent cam. Motor makes about 400 hp at the flywheel. So do I need a new performance custom chip burned? Or can I get away with stock one? Note this car is driven on the street and taken to the local drag strip about twice a month. It's my first vette! THANKS GUYS!
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
Great thank you! So questions #2 injected vs carburated. Is the injection system worth it, or would you guys not hesitate to go with a carb? Difficult to make the injection work right with built motor? I have all the stuff to go carburated but I would like to keep the injection as long as it won't be tons of money to make it run right.
Team Owner
Joined: Oct 2007
Posts: 26,745
Likes: 694
From: PA
Your TPI intake is going to take your "400" hp motor down a ton and goodbye to any top end power. That is of course unless you milodify the stock system. Also, the L98 exhaust manifolds will choke the hell out of it. There is even more power gone.
Probably 28 lb injectors and different runners, ported and matched of course, full exhaust and a tune.
Carbs are fine but there is a reason for fuel injection.
Probably 28 lb injectors and different runners, ported and matched of course, full exhaust and a tune.
Carbs are fine but there is a reason for fuel injection.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
Yeah, I was going to do injectors and try to bump up fuel pressure. This car already has an EGR delete so can I run aftermarket headers without the smog stuff without the computer going nuts? Will the new chip I get burned not care about the smog stuff? Recommendations for a company to burn my chip?
Team Owner
Joined: Oct 2007
Posts: 26,745
Likes: 694
From: PA
Either do it yourself or do datalog and transfer files for fine tuning. I am not a fan of mail order tunes for highly modified engines. Sensor read different on every engine and its just not as good as it can be. My fathers mail order tune, in my opinion, sucks.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
Wow ok thanks for the tip. I'm starting to think maybe carb? Seems like it would make more power and I can tune everything by hand on the spot. I know this is a dumb question but if went with a carb my instrument cluster and gauges would still all work right? Someone told they wouldn't which doesn't seem right to me. I think everything would still work if I run all the sensors in the new motor.
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Team Owner
Joined: Sep 2001
Posts: 62,146
Likes: 1,730
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Do not put a carb on that thing.
Formulate a plan to change the intake system and modify the exhaust. We will need specifics on the head size and cam profile to recommend something for you.
I did not catch that you were keeping a TPI intake on it. If so, it will not make 400hp any more. You will need to port out the plenum and runners and base manifold at a minimum, and also run headers, and even then it will not make 400chp.
Formulate a plan to change the intake system and modify the exhaust. We will need specifics on the head size and cam profile to recommend something for you.
I did not catch that you were keeping a TPI intake on it. If so, it will not make 400hp any more. You will need to port out the plenum and runners and base manifold at a minimum, and also run headers, and even then it will not make 400chp.
Team Owner
Joined: Sep 2001
Posts: 62,146
Likes: 1,730
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Do not put a carb on that thing.
Formulate a plan to change the intake system and modify the exhaust. We will need specifics on the head size and cam profile to recommend something for you.
I did not catch that you were keeping a TPI intake on it. If so, it will not make 400hp any more. You will need to port out the plenum and runners and base manifold at a minimum, and also run headers, and even then it will not make 400chp.
Formulate a plan to change the intake system and modify the exhaust. We will need specifics on the head size and cam profile to recommend something for you.
I did not catch that you were keeping a TPI intake on it. If so, it will not make 400hp any more. You will need to port out the plenum and runners and base manifold at a minimum, and also run headers, and even then it will not make 400chp.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
Do not put a carb on that thing.
Formulate a plan to change the intake system and modify the exhaust. We will need specifics on the head size and cam profile to recommend something for you.
I did not catch that you were keeping a TPI intake on it. If so, it will not make 400hp any more. You will need to port out the plenum and runners and base manifold at a minimum, and also run headers, and even then it will not make 400chp.
Formulate a plan to change the intake system and modify the exhaust. We will need specifics on the head size and cam profile to recommend something for you.
I did not catch that you were keeping a TPI intake on it. If so, it will not make 400hp any more. You will need to port out the plenum and runners and base manifold at a minimum, and also run headers, and even then it will not make 400chp.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
The fuel injection will give you better mileage and can be fine tuned if you have a good tuner to burn the chip.
The 85 set up has some restrictions.
#1 and well known is the exhaust system. Going to headers (if legal in your state) and duel exhaust will wake up the car.
#2 the plenum, runners and intake are a bottle neck.
#3 the 85 cast iron heads sucked.
If your going to a newer engine with a base of 400HP your going to restrict the HP with #2, headers will eliminate #1 and #3 should not be a problem.
When I changed to a ZZ4 short block with roller cam and AFR low compression heads (8.5:1) and large cc, I could get 30 MPG on the freeway for long trips....800-900 mile runs. Decent around town mileage. 13.2 @ 107 thru the 1/4. That was running stock exhaust manifolds into a 2.5" front "Y", removed cat (for racing) and bolted in straight thru pipe into 2.5" rear "Y". All with 3.07 gears and automatic transmission.
The 85 set up has some restrictions.
#1 and well known is the exhaust system. Going to headers (if legal in your state) and duel exhaust will wake up the car.
#2 the plenum, runners and intake are a bottle neck.
#3 the 85 cast iron heads sucked.
If your going to a newer engine with a base of 400HP your going to restrict the HP with #2, headers will eliminate #1 and #3 should not be a problem.
When I changed to a ZZ4 short block with roller cam and AFR low compression heads (8.5:1) and large cc, I could get 30 MPG on the freeway for long trips....800-900 mile runs. Decent around town mileage. 13.2 @ 107 thru the 1/4. That was running stock exhaust manifolds into a 2.5" front "Y", removed cat (for racing) and bolted in straight thru pipe into 2.5" rear "Y". All with 3.07 gears and automatic transmission.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
The fuel injection will give you better mileage and can be fine tuned if you have a good tuner to burn the chip.
The 85 set up has some restrictions.
#1 and well known is the exhaust system. Going to headers (if legal in your state) and duel exhaust will wake up the car.
#2 the plenum, runners and intake are a bottle neck.
#3 the 85 cast iron heads sucked
If your going to a newer engine with a base of 400HP your going to restrict the HP with #2, headers will eliminate #1 and #3 should not be a problem.
When I changed to a ZZ4 short block with roller cam and AFR low compression heads (8.5:1) and large cc, I could get 30 MPG on the freeway for long trips....800-900 mile runs. Decent around town mileage. 13.2 @ 107 thru the 1/4. That was running stock exhaust manifolds into a 2.5" front "Y", removed cat (for racing) and bolted in straight thru pipe into 2.5" rear "Y". All with 3.07 gears and automatic transmission.
The 85 set up has some restrictions.
#1 and well known is the exhaust system. Going to headers (if legal in your state) and duel exhaust will wake up the car.
#2 the plenum, runners and intake are a bottle neck.
#3 the 85 cast iron heads sucked
If your going to a newer engine with a base of 400HP your going to restrict the HP with #2, headers will eliminate #1 and #3 should not be a problem.
When I changed to a ZZ4 short block with roller cam and AFR low compression heads (8.5:1) and large cc, I could get 30 MPG on the freeway for long trips....800-900 mile runs. Decent around town mileage. 13.2 @ 107 thru the 1/4. That was running stock exhaust manifolds into a 2.5" front "Y", removed cat (for racing) and bolted in straight thru pipe into 2.5" rear "Y". All with 3.07 gears and automatic transmission.
Melting Slicks
Joined: Nov 2010
Posts: 2,216
Likes: 113
From: Michigan
c4 fans are set pretty high and you'll want them turned on sooner at least. The 85 ecm is one year only and I'd suggest upgrading to the 86+ version it's not that hard. When I shopped for my c4 I avoided 85's unless it was a super deal and I got a pretty good deal on my 86. With my 86 I decided to stick with TPI because of a lot of parts I had still from an 85 TA tpi(I upgraded the ecm), but if I had nothing I'd of went carb with all those parts I have. 24lb injectors should be fine on a choked down 400hp motor with tpi. There was a recent thread that said all gauge sensors are separate from the ecm, so yah they should work still if you go carb.
carb or tpi either will need parts and tuning
carb or tpi either will need parts and tuning
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
You won't make 400 hp with a TPI intake. You need a miniram or holley stealth ram to reach that number. The 24 lb injectors can handle 400 hp if the fuel pressure is set to 50 psi. You might need to use a walbro 255 pump though.
If you have gotten this far into it, I would seriously recommend getting a carb for this thing as tuning the '85 ECM is a nightmare. Took me 2 years to get mine tuned right and it's still not perfect. If you keep the fuel injection on this, it will make you hate the car solely because of tuning the ECM. When I did my mods, every aspect of my tune got thrown off. Every single one.
A carb is much cheaper in the end. Or you can purchase a self tuning fuel injection system for under 2 grand.
If you have gotten this far into it, I would seriously recommend getting a carb for this thing as tuning the '85 ECM is a nightmare. Took me 2 years to get mine tuned right and it's still not perfect. If you keep the fuel injection on this, it will make you hate the car solely because of tuning the ECM. When I did my mods, every aspect of my tune got thrown off. Every single one.
A carb is much cheaper in the end. Or you can purchase a self tuning fuel injection system for under 2 grand.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
You won't make 400 hp with a TPI intake. You need a miniram or holley stealth ram to reach that number. The 24 lb injectors can handle 400 hp if the fuel pressure is set to 50 psi. You might need to use a walbro 255 pump though.
If you have gotten this far into it, I would seriously recommend getting a carb for this thing as tuning the '85 ECM is a nightmare. Took me 2 years to get mine tuned right and it's still not perfect. If you keep the fuel injection on this, it will make you hate the car solely because of tuning the ECM. When I did my mods, every aspect of my tune got thrown off. Every single one.
A carb is much cheaper in the end. Or you can purchase a self tuning fuel injection system for under 2 grand.
If you have gotten this far into it, I would seriously recommend getting a carb for this thing as tuning the '85 ECM is a nightmare. Took me 2 years to get mine tuned right and it's still not perfect. If you keep the fuel injection on this, it will make you hate the car solely because of tuning the ECM. When I did my mods, every aspect of my tune got thrown off. Every single one.
A carb is much cheaper in the end. Or you can purchase a self tuning fuel injection system for under 2 grand.
Yea I agree I'm thinking carb. I own all the carb stuff minus the intake I would need to make it all fit under the hood. I would love to be a corvette purest if I could afford it lol. If I'm going to do injection I'm going to do it right. Just a blue collar guy with a father son project so money is tight. However when I do the carb conversion I'll do it right, not cutting anything, do it nice so I can always go back.
Melting Slicks
Joined: Nov 2010
Posts: 2,216
Likes: 113
From: Michigan
Yea I agree I'm thinking carb. I own all the carb stuff minus the intake I would need to make it all fit under the hood. I would love to be a corvette purest if I could afford it lol. If I'm going to do injection I'm going to do it right. Just a blue collar guy with a father son project so money is tight. However when I do the carb conversion I'll do it right, not cutting anything, do it nice so I can always go back.