Starting to Learn on 95 G30 5.7 for Towing

[donf]

Hi Don. I was pretty active tuning my stock 1995 K1500 several years ago. My tuning threads are here:

I've attached my bin if you want to have a look at it. Truck has nearly 180,000 miles on it now. Same stock LO5 and 4L60e.

Thank you I will take a look! I am sure there is some good stuff in there. Billy Graves has already helped me too with some trans help.

I read a Hypertech I found in a 92 GM van once. For $2 at the wrecking yard. All they did is target a leaner PE mixture and increase the VE table and spark map in the 80+ KPA range. I tried it and WOT it actually ran very well but no changes to anything that would effect emmisions.

No PE changes in the Jet chip. I did not bother to dyno it. I took it out after one trip pulling the trailer and dyno to the track. A lot of the changes were in the rpm ranges well past the limits of a stock 350 tbi. Every change over the stock chip is shown in this screen shot.

[Fast355]

Thank you I will take a look! I am sure there is some good stuff in there. Billy Graves has already helped me too with some trans help.


No PE changes in the Jet chip. I did not bother to dyno it. I took it out after one trip pulling the trailer and dyno to the track. A lot of the changes were in the rpm ranges well past the limits of a stock 350 tbi. Every change over the stock chip is shown in this screen shot.

They were probably just cleaning up the non calibrated GM mapping in that area. From the files I have seen over the fuel kill they put a flat lined timing and VE map from GM.

Where I see the best gains from tuning TBI chips is in the off-idle to 3,000 rpm range. The factory often used negative or very low advance values under load. Most of the engines I have played with like 8-10° of advance by 1,000 rpm, 20° by 2,400 and full advance of 26-28° by 3,600 rpm. That is only possible if they are not tunning lean like many do in factory form. I have gained 20-30 ft/lbs at the wheels running timing like that and a WOT air/fuel ratio of 12:1 in that RPM range. Up around peak HP in the 3,600+ rpm range taper off the fuel to about 12.6:1. Watch for knock retard with the trailer in tow and adjust accordingly until it goes away, then pull 2° more for safety. If running 91+ you can actually find yourself advancing the timing past the point of losing power without running into detonation.

[Fast355]

This is the timing map I had in my 7730 TPI ECM that was running a stock TPI intake on a 1-ton 8.8:1 350 TBI engine with a LT1 F-car cam in my 1983 G20 van. PE spark is high at the top rpm because the TPI runners and swirl port heads are choking off the airflow by that RPM. More timing kept the power from falling off quite as noticeably. It had good power to ~5,200 rpm.

[donf]

This is the timing map I had in my 7730 TPI ECM that was running a stock TPI intake on a 1-ton 8.8:1 350 TBI engine with a LT1 F-car cam in my 1983 G20 van. PE spark is high at the top rpm because the TPI runners and swirl port heads are choking off the airflow by that RPM. More timing kept the power from falling off quite as noticeably. It had good power to ~5,200 rpm.

Thanks for the ignition map! That is helpful. I will mess around this summer, but I am not going to do the cam swap, bowl blend until late September. I keep having to tow the dyno places when the weather is good. I did look at the dyno runs on the van and there were some leaner areas at low rpm with the stock fuel map, not crazy though, if anything its too rich in the higher rpm ranges but I only run it to 4000.

[donf]

A picture I took yesterday. The van has been towing fine all summer. One thing I never thought about when I rebuilt the 4l60e is the 3rd to 2nd gear spacing. Its not that great for towing. If I had to do it over agian I would have found a core 95 4l80e to make 2nd a little more usable. The 4l60e trans durability wise is fine so far.

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[donf]

I have some questions about the program that some say they use to generate shift points, Blue Cat trans table generator. The information it exports seems to be made for another tuning program (HP Tuners) leaving a lot of tables to the imagination. The lockup tables seem abbreviated, it generates something called shift slope, and the Vss ratio is in a very different format than TunerPro $0D. I ended up not using it at all but I am still curious just to learn what all the fuss was about when using it for TunerPro.

[donf]

I tore the intake/timing cover off last night. The block is fully roller compatible. So the my 14097395 cam will work. I have also been able to pick up a GMPP vortec intake and an Edelbrock 3704 for less than the cost of a cheap tbi plate. I am waiting to have my heads checked for cracks to see what manifold I use. Torque from 2000 to 4500 is what I am looking to improve. I really do not care about anything above that for this application.