Help on Launch control disable speed to control wheel spin during launching

[j.boy]

I was thinking on trying to control my wheel spin during Launching (drag) without feathering or fanning the throttle pedal by using the table launch control disable speed. With the goal in mind of getting better and constant drag strip time by decreasing rear wheel spin during launching.

At first, I checked what certain cruising speed on 1st gear at 3.8k RPM and noticed that it was at 16-17mph on my current wheel/tire setup.

I had then set my launch control at 3.8k rpm and launch control disable speed at 16mph, thinking that launch control would be maintained even on WOT until 16mph. (Goal : easier and constant launching and controlling wheel spin )

I was successful in doing this and data logged my rear wheel slip, RPM, Road speed, rear wheel and front wheel speed.

I was able to lessen the wheel slip duration during launching even on WOT, and acceleration was smooth until 6k rpm where it suddenly drops back to 4k rpm even tho i was flooring the accel pedal. my logs showed a sudden cut off on the throttle around the rpm range where rpm drops. (during this time i didnt eased off and was flooring the throttle pedal).

attached my datalog.. It happened on the 11th - 12th second on this log.

This sudden drop of RPM on WOT only happens on the 1st gear.

And if I decrease the LC disable speed , this problem doesnt occur.

[steve99]

assume you have pushed the centre console buttons to disable traction control and the stability control?

Also try disabling the Flat foot shift in the rom by setting the delta to zero, by default its 2000 rpm i think and it works of clutch switch which is very sensitive and may operate even if your just lightly touching clutch

[FRS Justin]

What is your 60ft time? What is your current suspension setup and tire selection? The key to launching is car setup not detuning. I launch at 7800rpm and drop the clutch wheel spin might be 3 feet. That is all motor n/a, of course boosted applications require tuning to help with launching but if your car is not dialed in your still be slow off the line the only difference is, being slow spinning and being slow detuned. That's a pick your poison no win situation.

[j.boy]

yes steve FFS wasn't set. only LC. and all those center console deactivated. (traction, VSC).

[j.boy]

FRS justin, i forgot the actual #'s bro, but im sure my 0-60ft was improved. the only problem was that sort of fuel cut off when 6k rpm was reached.

Not sure which wheel speed (front or rear wheel) our car's vehicle speed (the one seen on speedometer) is using. Its probably using the rear wheels in which our speedometer surely will gives off wrong data (higher readings than actual vehicle speed) during the time when rear wheel slips while launching.

Im assuming the LC disable speed is using vehicle speed (the reading on the speedometer) to disable launch control.

[ztan]

Originally Posted by j.boy

I had then set my launch control at 3.8k rpm and launch control disable speed at 16mph, thinking that launch control would be maintained even on WOT until 16mph. (Goal : easier and constant launching and controlling wheel spin )

I was successful in doing this and data logged my rear wheel slip, RPM, Road speed, rear wheel and front wheel speed.

I was able to lessen the wheel slip duration during launching even on WOT, and acceleration was smooth until 6k rpm where it suddenly drops back to 4k rpm even tho i was flooring the accel pedal. my logs showed a sudden cut off on the throttle around the rpm range where rpm drops. (during this time i didnt eased off and was flooring the throttle pedal).

attached my datalog.. It happened on the 11th - 12th second on this log.

This sudden drop of RPM on WOT only happens on the 1st gear.

And if I decrease the LC disable speed , this problem doesnt occur.

No log attached - would be interested to see vehicle speed where limiter is active.
If the problem doesn't occur with a lower disable speed, set it lower.

ps: I've seen different implementations of the LC code in different ROMS, some of which work, and some of which may not work fully as expected. The basic code in most of the OFT ROMS adds the LC delta to the RPM value and stores it as an engine RPM value. That value is then compared to the stock limiter. If the new RPM value with LC Delta added is actually used anywhere else in the code (it could be in your case) you may hit the limiter unintentionally.

[86 South Africa]

No chance of asking someone like EcuTek to look at the data?

[Kodename47]

Originally Posted by 86 South Africa

No chance of asking someone like EcuTek to look at the data?

Not if it's an OFT ROM

[86 South Africa]

Originally Posted by Kodename47

Not if it's an OFT ROM

LoL... my bad