base tune 402

[theoz385]

Maybe asking too much, but anyone have a base tune for an N/A 402ci LS2 in a 99 vette? Got TF 225 cnc heads, 90mm tb , 102mm Fast intake, 46lb Fast injectors, 239/248-113+3 cam and 1 3/4 LT's. The car had a blower before I bought it and installed the cam, injectors, and intake. As you would expect, it barely idles. Trying to learn this on my own, as you all probabely have, and very frustrating. Any help would be greatly appreciated. Thanks, Ted

[DrkPhx]

Is your name Ted and live in WI?

[theoz385]

yes actually

[DrkPhx]

yes actually

First, Welcome to the forum!

Thought so. Len sent me a copy of your tune (pre-mods that you just installed).

You basically need to start from a stock 99 C5 M6 tune and go from there because the existing tune is specific to the blower setup. First you need the correct Injector Flow Rate (IFR) specific to those injectors which are LS2 injectors rated at 58 psi (FAST LS1 injectors are normally rated at 43.5 psi) and you need to measure the fuel rail pressure with a mechanical gauge at the rail. This will help tremendously. I included a copy of the calculator.

Here are the values assuming you are at 58 psi at the fuel rail; once again verify your actual fuel pressure and input the number into the calculator.

G/SEC
5.7960
5.8321
5.8680
5.9037
5.9392
5.9744
6.0095
6.0443
6.0790
6.1134
6.1477
6.1817
6.2156
6.2493
6.2828
6.3162
6.3493

[DrkPhx]

Here's a copy of a stock tune for your car. Also, change the value in B4349 to 0.01915 if you have a 90mm TB. This is the ETC Throttle Area Conversion I usually use for a 90mm TB on a C5. There quite a bit more to do when it comes to a stroker, but try these. Did you get your scan tool set up yet? If not, you need to do this asap as it will become your best friend during the tuning process.

[theoz385]

Yes, Len is helping me with this but hate bothering him with it, or anyone else for that matter. Thanks for the tips. Why when I try to open a tune file like the stock tune you sent, do the calibrations come up as unknown?

[DrkPhx]

Yes, Len is helping me with this but hate bothering him with it, or anyone else for that matter. Thanks for the tips.

Understood, but it's never a bother to help someone with their tune. It's a pretty steep curve especially when dealing with a stroker motor. Frustration can set in pretty fast. Did you set up the scan tool yet? If not, make sure you do this before tuning.

Why when I try to open a tune file like the stock tune you sent, do the calibrations come up as unknown?

It shouldn't. Try to save it instead of opening it. Either way it should work and show the calibrations.

BTW - If that doesn't work, follow the link below and look for 99 Corvette Manual Operating System 12593359

http://www.holdencrazy.com/EFILive/stockTunes.php

[Steve Bryant]

DrkPhx,
I opened the tune directly without saving it and it worked fine for me.

theoz385,
Welcome to EFILive. Like DrkPhx said, the learning curve is fairly steep, but there are a lot of folks willing to help you get up the slope. Try opening some of the sample tunes that come with EFILive.

1. Then try to open a few more from holdencrazy.com.
2. Do you have a wideband oxygen sensor with an output for logging AFR?
3. Do you have a friend with an LS1 based engine that you can log some data from? This could be a truck or a car. You need to get comfortable with logging before you try anything about tuning.
4. Do you plan to run with a mass air flow sensor or just run speed density?

Right now, I'd just take a deep breath and relax as much as possible as there are people who will help you.

All my best,

Steve

[theoz385]

Thank you so much for your willingness to help out. Really appreciate it.