Modded C4 Corvette tuning, help wanted.
Thread Starter
5th Gear
Joined: May 2024
Posts: 5
Likes: 0
Modded C4 Corvette tuning, help wanted.
Hi y’all, this is my first ever time posting here so forgive me if this post isn’t formatted correctly. I’ve got a 1991 corvette, L98, that I am thinking about tuning. I have zero experience tuning so please try to format your response in a way I can follow and learn. The rpm cam is supposed to reach 6500 rpm’s and this car from my understanding only wants to do about 5-6k. So I think I’ll need an aftermarket computer. Tbh idek what a computer is I just know I’ll need one. Mods/recent fixes listed below, help on what my next step should look like would be much appreciated. I was running 91. I think that’s why the heads blew, gonna move up to 93 or higher.
There’s a good chance I forget something. I’ve put a lot of time, money, and parts into it.
- Edelbrock performance heads
- Edelbrock rpm cam
- Crane roller rockers
- Bored 30 over
- Forged pistons
- New crank shaft
- New high flow oil pump
- New bearings
- New Edelbrock head gaskets
- New wires and plugs
- New fuel pump
- Serviced the heads and got a valve job.
- New Toyo racing tires
There’s a good chance I forget something. I’ve put a lot of time, money, and parts into it.
- Edelbrock performance heads
- Edelbrock rpm cam
- Crane roller rockers
- Bored 30 over
- Forged pistons
- New crank shaft
- New high flow oil pump
- New bearings
- New Edelbrock head gaskets
- New wires and plugs
- New fuel pump
- Serviced the heads and got a valve job.
- New Toyo racing tires
Last edited by tcs0110; May 10, 2024 at 10:52 AM. Reason: Format error.
Thread Starter
5th Gear
Joined: May 2024
Posts: 5
Likes: 0
I had an entire reply written and this damn website crashed. I want both. I want to learn and have some basic skills, so like another mentioned ecm. I have no idea what that means, what it does, where it is. So explain the tuning terms. And then ultimately I want to have a good, professional tune my car. So the advice I need is what should I do in between now and getting that tune? Because I know the 91 computers aren’t really advanced enough to handle what I want. But I only know that because a mechanic who’s helping me with it told me that. So idk how to fix that issue.
Thread Starter
5th Gear
Joined: May 2024
Posts: 5
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I have the K and N cold air intake, idk if that changes what you said or not. The plenum came with the head gasket kit if I remember correctly, that’s Edelbrock, at this point most of the engine is Edelbrock, I think there’s a couple crane parts too. Not sure what runners are though, also don’t know what ecm is. Sorry, I’m very new to this world so I’m trying to learn as I go.
Drifting
Joined: Nov 2018
Posts: 1,760
Likes: 647
From: USA
I have the K and N cold air intake, idk if that changes what you said or not. The plenum came with the head gasket kit if I remember correctly, that’s Edelbrock, at this point most of the engine is Edelbrock, I think there’s a couple crane parts too. Not sure what runners are though, also don’t know what ecm is. Sorry, I’m very new to this world so I’m trying to learn as I go.
Thread Starter
5th Gear
Joined: May 2024
Posts: 5
Likes: 0
ECM (engine control module)= computer = brain for your fuel injected engine. Controls timing, fuel injectors, cooling fans, etc. 6,500 rpms is not why you need to update/upgrade your tune, you need the ECM calibrated to the new parameters of the changed components. Typically a TPI (L98) is done making the most power long before 6,500 rpms. You've invested a lot of money, make sure you invest in the proper tuning, I would be finding the closest reputable person to do just that, I would not run or drive it anymore than absolutely necessary, until this is done! How about some pictures? Good luck👍
thanks for the help
Melting Slicks
Joined: Jul 2005
Posts: 2,221
Likes: 302
Clearly there are more advanced ECMs. But the 91 ECM is easily able to handle your combo IMO.
With Tunerpro and PROM emulators and ability to patch in a wideband O2 for AFR data recording, ts a very tunable ECM.
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Burning Brakes
Joined: Aug 2023
Posts: 1,093
Likes: 35
From: San Diego
He doesnt know what he's talking about. Its actually amazing how much fidelity is built into an ECM of that vintage with how many fuel and spark parameters there are to customize.
Clearly there are more advanced ECMs. But the 91 ECM is easily able to handle your combo IMO.
With Tunerpro and PROM emulators and ability to patch in a wideband O2 for AFR data recording, ts a very tunable ECM.
Clearly there are more advanced ECMs. But the 91 ECM is easily able to handle your combo IMO.
With Tunerpro and PROM emulators and ability to patch in a wideband O2 for AFR data recording, ts a very tunable ECM.
Melting Slicks
Joined: Jul 2005
Posts: 2,221
Likes: 302
AUJP is for Camaros obviously, but the basic code is the same for Corvettes with just a few parameters changes.
Intermediate
Joined: Jan 2024
Posts: 35
Likes: 8
Hi y’all, this is my first ever time posting here so forgive me if this post isn’t formatted correctly. I’ve got a 1991 corvette, L98, that I am thinking about tuning. I have zero experience tuning so please try to format your response in a way I can follow and learn. The rpm cam is supposed to reach 6500 rpm’s and this car from my understanding only wants to do about 5-6k. So I think I’ll need an aftermarket computer. Tbh idek what a computer is I just know I’ll need one. Mods/recent fixes listed below, help on what my next step should look like would be much appreciated. I was running 91. I think that’s why the heads blew, gonna move up to 93 or higher.
There’s a good chance I forget something. I’ve put a lot of time, money, and parts into it.
- Edelbrock performance heads
- Edelbrock rpm cam
- Crane roller rockers
- Bored 30 over
- Forged pistons
- New crank shaft
- New high flow oil pump
- New bearings
- New Edelbrock head gaskets
- New wires and plugs
- New fuel pump
- Serviced the heads and got a valve job.
- New Toyo racing tires
There’s a good chance I forget something. I’ve put a lot of time, money, and parts into it.
- Edelbrock performance heads
- Edelbrock rpm cam
- Crane roller rockers
- Bored 30 over
- Forged pistons
- New crank shaft
- New high flow oil pump
- New bearings
- New Edelbrock head gaskets
- New wires and plugs
- New fuel pump
- Serviced the heads and got a valve job.
- New Toyo racing tires
New .001 undersized tri-metal bearings (clevite).
Standard bore with stock pistons.
New standard bore moly rings (speed pro).
Stock standard pressure oil pump.
Cloyes double roller timing chain (stock timing position).
Summit stage 4 8803 camshaft with stock roller lifters 224/232 Dur. 112 LSA + 2 Adv, .550/.540.
Flotek 200cc street build aluminum heads (angle plug, 2.02/1.60 valves, 200cc intake runners, 78cc exhaust runners, 64cc chambers).
Brian Taylor Racing Chromoly pushrods (7.8" length).
Comp cams valve springs, seats, retainers.
Fel-Pro .015" shim head gaskets (to retain compression ratio {under 1 cc difference}).
Cast steel 1.5 ratio roller rockers.
Hedman painted long tube headers.
Accel billet HEI distributor with mechanical and vacuum advance.
Stock GM HEI coil
New 8mm spark plug wires
NGK plugs
Edelbrock performer EPS intake.
Edelbrock Thunder AVS 650 cfm carburetor.
14" x 2" reusable air filter.
160° thermostat.
180° fan thermoswitch.
Aux and main fans wired together to run in unison.
New Ethylene Glycol coolant.
Smog pump and catalyst delete.
Innovate LC-1 wideband O2 gauge in a-pillar.
Cleaned and serviced oil cooler in excellent condition.
STATIC Compression Ratio: 9.59:1
DYNAMIC Compression Ratio: 8.11:1
Thread Starter
5th Gear
Joined: May 2024
Posts: 5
Likes: 0
Do I NEED to?
Another question for all y’all. I’ve got some people saying I NEED to tune it before driving it and especially before racing her. I’ve got some people saying I can give her hell right away without a tune, but to expect less power than what my parts are capable of. So my other question is, do I NEED to tune it before testing the build? Will I cause damage if I don’t?
Burning Brakes
Joined: Aug 2023
Posts: 1,093
Likes: 35
From: San Diego
Get a tune prior to starting it. Might as well get it done right. Dont want the engine to wash cylinders down with too much fuel, if it says it needs it etc.
Many great tuners can get you very close so all you will need is to fine tune it with a lot of data logging.
Many great tuners can get you very close so all you will need is to fine tune it with a lot of data logging.