Scaling VE and Injectors 20% affect on Transmission Pressures of A4?

[mjmenke1]

I scaled my VE tables and Injectors 20% to keep my car from going into Reduced Power at upper RPMs/ Boost. My understanding from what I've read is that torque calculations are derived using airflow and a few other variables. Scaling would affect those calculations so my Delivered Engine Torque used in Transmission Pressure would be incorrect. The calculation would be lower than actual torque.

How can you adjust for this?

2004 Corvette Level X RPM 4L65E, 427, 23lbs boost, 2.5 bar OS

[joecar]

Yes, it's a problem... you might have to turn the hex screw on the end of the PCS in 1/8th turn.

Log the pids GM.ENGTRQ and GM.TFMPRS (and the usual other pids), post a log.

[mjmenke1]

Yes, it's a problem... you might have to turn the hex screw on the end of the PCS in 1/8th turn.

Log the pids GM.ENGTRQ and GM.TFMPRS (and the usual other pids), post a log.

Thanks for the reply. I can't do any logging right now the car is having some paint work done. Should get it back by mid next week.

I just had to replaced the tranny, last one started slipping really bad 3rd and 4th at WOT shortly after I switched from a HP OS to an EFI OS (could be attributed to normal wear). I didn't log any tranny related PIDs prior.

In the HP tune I believe the scaling was compensated for by modifying the Force Motor Current Table. Changing the current applied at temps to achieve needed line pressure after the scaling. Has this table (D3801) been adjusted by anyone to offset scaling with EFI Live?

Would changing Base Pressures values of D0701, 2, 3 up to 96psi negate the VE scaling I've done or is that only affecting the shifts not normal pressure in gear? Maybe leaving values lower 0 to 300 less than max pressure in D0701?

[ddnspider]

Thats interesting, I scaled my tune 30% and had no issues with shifting or anything like that, but I did also leave on all torque reduction on shifts to keep the trans alive. My base pressures ramp from 0-90psi on D0701/2/3. I'm not making near the power you are, but 700fwhp on a stock 4l60e aint bad. You could ramp the base pressures up to 90 psi at a lower torque value. I had always heard to leave the force motor current alone.

[joecar]

You can edit the Force Motor Current table D3801.

Tables D0701-3 look to me to only increase pressure during shifts

If your trans died from slipping, run a pressure gauge to the line tap and view what it does as you drive.


~ by phone ~

[joecar]

I've seen scaled cases where line pressure was sufficiently high and the trans was ok.

I've seen other scaled cases where the line pressure dropped due to something else not being quite right (either in the tune and/or physically in the trans).

~ by phone ~

[mjmenke1]

My tranny has been lovingly abused shifting into 4th doing 1/2 drag races with around 1000rwhp. I'm hoping to get the tranny tune as good as it can be for this type of racing knowing it will not last long term. I have the motor side of the tune close to where I want it but neglected learning about tuning the tranny properly while I was learning about tuning the motor. Having the tranny go out on the first run of a race weekend, paying for the rebuild, and the hours of my time changing it out has reminded me the tranny tune is very important.

[joecar]

If it's a racecar then you might install the line pressure gauge as permanent fixture... and a temperature gauge also.

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[ddnspider]

If it's a racecar then you might install the line pressure gauge as permanent fixture... and a temperature gauge also.

Sent from my LGMS345 using Tapatalk

I'm pretty sure there's a TFT parameter that let's you monitor Trans temp, is that not accurate?

[mjmenke1]

Its not a full race car, its still driven on the street for the most part. Adding gauges isn't my first choice because I've already have 3, fuel pressure, boost, and AFR. Would be nice to have tough, thought for down the road. Tranny temp can be monitored on one of the cluster settings.