ls1 4l60e swap into a 68. Just bought the car, no history. I'm not a trans tuner, never looked at one.
In gear idle too high, will go to 25 mph off gas. Shift points way too high and slams gears. At highway speed breathing on the gas pedal will cause it to drop out of overdrive. Has bad cruise effect.
Looking for a nice behavior, like my stock '04 ls1 vette had. Any help appreciated, will post any screen wanted.
cruise.pngnormal1.pngperf.pngurband1.png1968corvette.hpt
Last edited by thibble; 08-30-2017 at 05:43 PM.
Disclaimer, I am no pro tuner. Very amateur. However for years I have been doing trans tweaks, and very basic engine things. Engine, Im not going to try to advise you, but I feel like i have some data from a few 4l60s I have done that should help.
Ill show some pics comparing yours to a tune I like, yours is on the left.
I also have my shift times pretty short like yours, however i have some delay in a few areas, unlike yours where its straight across the board ZEROS.
My Shift pressures are higher than yours, and I have a short list of TCC tweaks that you might like.
So Ill post some pics of what i believe to be the big reasons your shifts are poor. and Ill post my tahoe tune, I know it sounds crazy, but i bet it would be a decent start on that 68 as well. Then you can get in there and tweak the speeds and RPMs of where you shift.
BEST OF LUCK!
Below is a link to a folder with a dozen pics to check out, and my tahoe tune you can pick from. I recommend copying over some of those TCC figures as well. I have found some great gas savings in there.
Thibble Google Drive Photos
Tahoe Tune
Last edited by asb2106; 08-31-2017 at 09:17 AM.
Tony B
02 TrailBlazer LTZ 4.2/4l60e
01 2500 suburban 6.0/4l80e
01 2500 suburban 8.1/4l80e
Lower your idle rpm if it's too high, it's way up there around 900-1000rpm. Try lowering it to 700 or something.
Make sure you have zero vacuum leaks and that the MAF and VE are tuned in good.
The normal part throttle 100% tps column does not match the full throttle rpm for normal and performance. You have 45 and 88mph in one and 54 and 97 in the others. If you don't want them to shift that high try putting them back to 45 and 88 as they should match.
Agreed on the shift times, add some time back in there. Like .150-.200.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
That is really great, thank you.Originally Posted by asb2106
Cool good info. With these two posts I'm getting an idea how to read these now. Also discovered speedo off 8mph-ish at 55, sure enough the ratio is wrong, probably not helping.
Okay this is great. Idle is good now at 700 after warmup, shifting is silky smooth and right on time. You guys rock. One thing left. Speedo. Darned if I can figure out the calc for mi-1. I have a 3.08 rear and 225-70/15 tires. I would know how to plug in height or circumference, but it doesn't ask for that.
speed.png
There is a gear/tire wizard in the edit tab, use that to adjust the gear ratio and your new tire size.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
go to edit--- gear/tire wizard
Michael Bray
Rusty Knuckle Garage
Slidell, Louisiana
20yr Master Tech.
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Custom Car Fabrication, Customization, High Performance.
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