Was my car previously tuned?

[njoossens]

I purchase my 2001 Corvette last year. Looked stock other than MSD wires and aftermarket shift knob. After working on it I have seen signs of previous modifications that were returned to stock. Looks like it had headers due to a broken header bolt we found while putting a new set of headers on. Also has no CAGS, previously had a shifter removed, had MSD plugs and iridium plugs, and a few other things. No big deal, just curious what it had before. After getting my EFI live I noticed a few things that make me think it has a partial tune. I am still VERY green to tuning, but the most glaring thing I saw was the Cat protection disabled. My current mods are air intake, long tube headers with cats, catback. Unsure if it is a stock thermostat or not. I went to the holden crazy site and did a comparison to my tune to the stock one for that year. Here are the differences. Please let me know if anything is glaringly bad.


Comparison summary: 08:52:02 pm, Tuesday Aug 03, 2010

Calibration comparison between 2001 Chevrolet Corvette Coupe Manual LS1 5.7 Litre (12593358).tun and 2001_Corvette_Stock.tun.
*Values that differ by more than 0.100000% are considered different.


B0701 "Catalytic Converter Protection Enable" N/A "CAL: Enable <-> ALT: Disable"
B5913 "Spark High-Octane Table" 10.4632 "Different from cell: 13,8 to cell: 28,24 inclusive."
B5914 "Spark Low-Octane Table" 10.4632 "Different from cell: 15,12 to cell: 28,24 inclusive."
B5919 "Optimal Timing" 11.1572 "Different from cell: 0,0 to cell: 14,19 inclusive."
B1901 "Max Allowed Engine Torque" 22.5788 "CAL: 474 <-> ALT: 866"
B6601 "Axle Torque Limiting" N/A "CAL: Enable <-> ALT: Disable"
B6614 "Max Torque By RPM" 32.1080 "Different from row 0 to row 20 inclusive."
D1001 "TCC Apply Speeds - Second Gear" -0.3891 "Different from cell: 3,0 to cell: 3,5 inclusive."
D0404 "CARS Vehicle Speed Enable" -5.0783 "CAL: 24 <-> ALT: 3"
D0405 "CARS Maximum Vehicle Speed Enable" -7.0315 "CAL: 31 <-> ALT: 2"
G0901 "Fan #1 Turn-on Temp" -15.6501 "CAL: 108 <-> ALT: 80"
G0902 "Fan #1 Turn-off Temp" -15.5416 "CAL: 104 <-> ALT: 76"
G0903 "Fan #1 Turn-on By A/C Temp" -0.1085 "CAL: 85 <-> ALT: 85"
G0913 "Fan #2 Turn-on Temp" -13.2407 "CAL: 113 <-> ALT: 89"
G0914 "Fan #2 Turn-off Temp" -13.8051 "CAL: 109 <-> ALT: 84"

[WeathermanShawn]

Overall, those tuning changes are 'no 'biggie'. Looks like the Fans were adjusted, skip shift, some Torque management, etc. Spark also. Tough to say what all changes were done without posting the tune.

Don't get too freaked out about Catalytic Converter protection set to Disable. From the factory, when you go WOT the PCM adds ~20-25% additional fuel. This is too keep the cats cool. I have cats and have CAT Converter Disabled for several years. The problem is that all that additional fuel cuts power. As long as you do not do multiple 10-15 second WOT runs, your Cats will be O.K.

Hope that helps. The changes appear to be normal.

[njoossens]

Thank you. It's a big help. I'm not overly worried. More curious, car seems to run great. Still learning what I can. I just started playing with it a bit this week. Turning off the p0420/p0430 messages. Looking at those numbers does it appear it has a 160 degree thermostat? Or at least the fan settings for one? I'll see if I can post my current tune.

[WeathermanShawn]

It at least appears to have the Fan Settings for ~ 160F Thermostat. If you find your fans are running all the time, you might want to research some threads on different T-Stat settings. It is pretty useless to run the fans continuously.

Was the VE Table worked?

Spark Table is somewhat odd. It is an aggressive Spark Table, but it has some odd 'holes' at differing cylinder air masses. Was it dyno-tuned?

You do not have to worry about Cat Converter set to disable. Your PE Table B3618 is quite rich. If you have a wideband you might want to dial your AFR in a little leaner.

That is it for now. Good luck..

[njoossens]

I really appreciate you looking into this for me. I've got an FJO wideband that still needs to be hooked up. Need to figure out the best way to run the wires down to it. I haven't personally had any tuning done and do not really know the history of the car. Bought it from a Carmax in the chicago area last year. Only changes I have made in this tune were the 420 and 430 codes that I set to not trigger the CEL. Other than that I was assuming it was stock until I started looking into the current tune and comparing it to a few things I read on here. I haven't noticed the fans running an excessive amount, but I'll keep an eye on it and see.

[joecar]

nj welcome to the forum :cheers:

[njoossens]

Thanks. I'm sure I will be back soon once I get my wideband hooked up. Now I'm just trying to read as much as I can.