1997 Vette 418 tune help

[ultradriver10000]

So I've been trying to learn how to tune better and need some pointers with my 1997 corvette. It has a forged 418 with ls3 heads, it has a stock ls3 intake and 1 7/8 headers. Heads are cnc'd and polished with about a 236/244 cam 624/628 lift if i'm remembering correctly.

The issues I'm having are hanging up rpms with the AC on. If I'm driving around with the AC on and not beating on her it will stay up at 1500rpms until I stop or blip the throttle. I can also hit the AC button and the idle will drop right down.

One log is a cold start with some surging until the car warms up AC on. The other log coming back from my friend Robby's house was a warm start and the car idled for a bit before I left.

In 95+ text heat my coolant temps will eventually get fairly high 235 degrees sometimes. I pulled out the radiator and AC condenser and blew and power washed them. 160 t stat and a stock rad, do I need to go with a triple core rad with an oil cooler possibly?

I want to get the driveablitly in good shape before I start to spray her.

Any ideas on the knock between shifting?

***started with a tune from a local guy that I'm trying to improve upon***

Tune
1997 corvette - Mod 1a.hpt

Log 1
C5 cold start with ac to gym.hpl

Log 2
c5 robbey.hpl

[ultradriver10000]

Did a bunch of stft tuning trying to get that to stay within +/- 5%.

The plugs fouled out, I'll pull them tomorrow. I'll post pictures of the plugs and the new tune file with improved VE table.

[2xLS1]

Your LTFTs spend a lot of time at +25% with STFTS considerably higher than 0%. Looks like you are trying to run a MAF only tune with no VE input (High RPM Disable = 200). Your high fuel trims could be from the injectors scaled wrong or that you are taking a lot of fuel out with the MAF table, or low fuel pressure. The only injector table you changed is the Flow Rate. Only other things I noticed are your PE enable TPS settings are pretty high. (90% typical of what you would see in a stock truck tune) and you are pulling a lot of timing out compared to stock. All these comments are based on comparing your tune to a stock 97 Vette M6 file I have.

[ultradriver10000]

^ ok ok Thank you, I'm still learning here.

So After getting the VE as close to +/- 5% (Most cells are in the 7-9% range) I set the high rpm disable to 3500rpm. So this is telling me anything below 3500rpm and not in PE will result in a blending of the VE and the MAF correct?

I changed the PE enable to stock settings, I'm not entirely sure why this was changed. (Guy tuned my car so I could start driving it but it needs to be refined obviously.)

I'm also not sure why my car is getting so hot. I guess with 105 degree temps outside the stock C5 rad can't keep up with the AC on? Its a brand new engine... :-/

[2xLS1]

^ ok ok Thank you, I'm still learning here.

So After getting the VE as close to +/- 5% (Most cells are in the 7-9% range) I set the high rpm disable to 3500rpm. So this is telling me anything below 3500rpm and not in PE will result in a blending of the VE and the MAF correct?

I changed the PE enable to stock settings, I'm not entirely sure why this was changed. (Guy tuned my car so I could start driving it but it needs to be refined obviously.)

I'm also not sure why my car is getting so hot. I guess with 105 degree temps outside the stock C5 rad can't keep up with the AC on? Its a brand new engine... :-/

You can only tune the VE if you fail the MAF and are in 100% Speed Density mode. And in your case it will be using the secondary VE table if you do that. I see very little changed in the VE table. Inputting the correct Cylinder Vol in the Engine General tab will at least scale the VE tables for the bigger engine displacement. Then you should tune it from there.

[ultradriver10000]

So I turned the MAF freq to 0 and logged some stft....

Here are the consecutive logs only changing the VE tables by multiplying % 1/2

sat ve tuning4.hpl
sat ve tuning5.hpl
sat ve tuning6.hpl
sat ve tuning7.hpl

So this log is the tune i'll attach in the next post. Its super hot out and the car is still pulling a bunch of timing. Any reason why? The header cracked on me, scared the sh*t out of me. I'll be buying new headers now I suppose.
911.hpl

[ultradriver10000]

So this is the latest tune.... Is there is reason why you'd run only a MAF tune vs VE/MAF?

1997 corvette - Mod 2a.hpt

These are the plugs, just pulled them...





Header eeeeeek Fml

[2xLS1]

Several things. Your primary and secondary VE tables don't match by row. Without seeing the tune you used while you think you were in SD mode, I can't say if you did it right. There are plenty of threads here how to run SD so I'm not going to repeat the procedure. Whatever you were doing, you didn't match the 2 VE tables by row. Looks like you changed a lot of other things too like disabling the LTFTs. I'm not saying that is a bad thing because I do it sometimes too. The histograms show some really + stfts in some really high MAP areas where you should be in PE mode. You are still pulling a lot of fuel with the MAF table you are using, especially in the higher airflow areas. You might try putting the MAF table back to stock. You still have only changed the IFR table for the injectors you are using. There are other tables you should change but I'm guessing you don't have the data for those other tables. Some of your logs show really high rpms, with pretty low TPS values. Could be just the way you were driving it. Looks like you blew off one of the AIR tubes on the header. You could always try just welding a small patch over the hole. As for the plugs, you can't tell much by looking at them other than they look like they are fine wire platinum or other type. I would use a regular plug like a NGK TR55 or if you are going to spray it something like a NGK BR7EFS.

[2xLS1]

And as far as running a MAF tune without using the VE, I wouldn't on a calibration that has a normal VE table. Some people like to run them on later model vehicles that use a virtual VE table to eliminate having to mess with Bluecat's software to tune it.

[ultradriver10000]

I'm an idiot I was just copy /paste the primary to secondary, I didn't realize I had to copy the rows. I ended up disabling the long term until I could get the short term stuff nailed down. The plugs are TR7IX, I want to pull them to read them a little and make sure I wasn't going to destroy anything. I didn't want to floor it too much, in order to keep it out of PE mode for logging. It was definitely how I was driving. I'll leave the VE tables like they are now and work on the MAF. I tried to follow most of the recommended practices on getting the VE tables dialed in. I'll start to get the MAF tuned. I don't have any injector data other then that they are ls3 resized to 42 lbs.