Launch control

src · Post by **src** » Sat Dec 12, 2009 4:40 am

Matt, just try it by yourself. My files attached.

4x4le · Post by **4x4le** » Mon Dec 14, 2009 5:59 pm

I forgot all about getting a vid of my rev limiter that is spark retard

http://www.youtube.com/watch?v=knpGoD2t9QU

Im not just in nuteral revving it, however I am hitting it long enough under a load that you can hear it

Legionnaire · Post by **Legionnaire** » Mon Dec 14, 2009 10:24 pm

nice pass! What are your EGTs like when you hit rev limiter? And how much do you retard your ignition past TDC to prevent engine from revving up?

4x4le · Post by **4x4le** » Tue Dec 15, 2009 11:03 am

Thanks,
I do not have an egt gauge in the car so i cant say that i know. The timing is mearly set at 0 and the fuel cut comes in 50rpms after the spark retard so i would assume things arnt getting out of hand too bad. Ive been slamming the limiter all year and i love it haha.
The revs are very stable, the rpms dont really creap.

I know the flames indicate high egt's but its mearly a flame thrower kit. I also am running the engine on e85 if that makes any difference to you.

Legionnaire · Post by **Legionnaire** » Tue Dec 15, 2009 11:56 am

Hey, thanks for info, so timing is 0 and revs don't creep, hmm. That's good to know, i thought some 10-15-20 degrees ATDC would be required.

As for flames - that's not nesessarily a sign that egt's are high, just some unburnt fuel finds its way to exhaust. My RB25 did it on overruns/decel when i added catless turboback and ran totally stock ECU.

4x4le · Post by **4x4le** » Tue Dec 15, 2009 1:41 pm

I think the main reason for the lack of creep is due to the fuel cutting 50 rpms after the ign retard. Boost however may creep on some setups, I know I have 0 lag even if off the throttle for a second after hitting the limiter. I bet it really spins that thing!

Now, I do have a question because I did want to experiment with retarding the timing atdc, however Im too much of a panzy to figure that one out myself. I know the way to get negative timing figures is to continue to add timing until it wraps around, but is the first set of negative figures the ones you want or do you need to let it go back into the positives and then back to the negatives? I would think we would be igniting the intake or exhaust stroke if we got it wrong.

src · Post by **src** » Sat Dec 19, 2009 10:20 pm

hey, guys, your rev limit talks seem to me off-topic

matt, what about my question?

4x4le · Post by **4x4le** » Sun Dec 20, 2009 1:19 am

I dont see how its offtopic considering why i brought it up. I was suggesting limiting the revvs in launch controll in the same manner that im limiting my total revvs. It will build boost at low rpms and would be great if it could switch to normal maps with a switch.

Legionnaire · Post by **Legionnaire** » Sun Dec 20, 2009 3:53 am

src, how is it offtopic - we're discussing ign retardation to get some desent boost level at adequate rpms so that we can have a good launch without bogging down and at the same time not to burn all the rubber standing still?

4x4le
Nice idea about adding timing until it "wraps around" as you say - i never thought of it. Do you think it will really work? In my case (r34 skyline) it goes to 63 deg. advance then shows -64 degrees. I have no idea if this is an actual -64 figure i.e. atdc or 64 deg btdc. What i know is that timing is calculated as a subtraction from a "base offset" that is usually set at 110 (6E hex). How exactly this operation is done, i don't remember - need to look into code, but this might allow us to set retarded timing by changing base offset.

Matt · Post by **Matt** » Thu Dec 24, 2009 6:56 pm

src - i've got it on my investigate list. will have a look at it during the week

src · Post by **src** » Sun Jan 03, 2010 3:11 am

Happy new year! Any updates?

Mads B (dk) · Post by **Mads B (dk)** » Tue Feb 16, 2010 2:05 am

any news ?

Matt · Post by **Matt** » Wed Feb 17, 2010 11:08 pm

uuugh. so much for next week. Just too busy at the moment

BlueRB240 · Post by **BlueRB240** » Wed Mar 10, 2010 6:22 pm

Could this be added to work with the Type 2 boards? My too big turbo on too small motor could use the help getting off the line lol.

skyline_stu · Post by **skyline_stu** » Thu Mar 18, 2010 1:08 am

I've written a small routine to run this on 50F00/50F05 ECU's - S13 SR20DET. I'm going to be testing this out later this week. If it proves to be successful, I'll be offering it as an upgrade to your current tune.

I'll keep you guys posted towards the end of the week..

When this becomes a reality (it technically is now), I'll need your ECU send to me to be upgraded as a new ENT file will be required to be burnt to your board. Other vehicles will be catered for in the near future.

Code upgrades and postage costs will be advised after field testing

Send me a PM if you are interested, even if it's not a 50F00/50F05 based ECU

Stu
Stu Cornall Tuning Services

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Launch control

Re: Launch control

Re: Launch control