[Carl Morris]

Restarting here...didn't realize I'd put this in the N55 section.

Downloaded ATR last night and started poking around. Made a few map changes I'd been wanting to try and noticed that there was a separate rev limiter for each gear, including "Gear 0". In Stage1+Aggressive the Gear 0 rev limit was set to 68xx, so I pulled it down to 4k to see what would happen. I was hoping it would either hold the revs down when the shifter was in the neutral gate (meh) or while the clutch was in (whoohoo!). So, I saved a map with these changes, loaded into the AP, and loaded it onto the car this morning before the drive to work.

Good news and bad news. The good news is that it's clutch activated and seems to work correctly for launching. I need to play with it some more and raise the rpm because right now it just bogs badly at 4k, but it basically does what I want. The bad news is that when also using it to shift without lifting, the code "remembers" the lower rev limit when you bounce off it during the shift and the lower rev limit continues to be active until you push the clutch in and let it back out without bouncing off the limit. So at this point it doesn't seem to be useful for NLTS. It's just code, though, and hopefully this will change at some point in the future.

Anyway, I'm quite psyched to see ATR and play with it. Next I'll raise the launch rpm and if I'm still bogging at 6k I'll play more with the rpm window between where the fuel cuts and where it comes back in, and then pull some timing in just that area if needed.

[Lulz_M3]

Good stuff, thanks for sharing.

[OpenFlash]

What you really want is an ignition cut, not throttle cut. That way the throttle is open from the launch all the way to the end of the run. If you limiting revs by throttle closures, your boost with discharge and you'll have to spool up the turbo again between gears. I found this to be critical during the 1-2 shift especially.

[E90SoFlo]

Why isn't shiv a sponsor..

[nafoo]

Originally Posted by Carl Morris

Restarting here...didn't realize I'd put this in the N55 section.

Downloaded ATR last night and started poking around. Made a few map changes I'd been wanting to try and noticed that there was a separate rev limiter for each gear, including "Gear 0". In Stage1+Aggressive the Gear 0 rev limit was set to 68xx, so I pulled it down to 4k to see what would happen. I was hoping it would either hold the revs down when the shifter was in the neutral gate (meh) or while the clutch was in (whoohoo!). So, I saved a map with these changes, loaded into the AP, and loaded it onto the car this morning before the drive to work.

Good news and bad news. The good news is that it's clutch activated and seems to work correctly for launching. I need to play with it some more and raise the rpm because right now it just bogs badly at 4k, but it basically does what I want. The bad news is that when also using it to shift without lifting, the code "remembers" the lower rev limit when you bounce off it during the shift and the lower rev limit continues to be active until you push the clutch in and let it back out without bouncing off the limit. So at this point it doesn't seem to be useful for NLTS. It's just code, though, and hopefully this will change at some point in the future.

Anyway, I'm quite psyched to see ATR and play with it. Next I'll raise the launch rpm and if I'm still bogging at 6k I'll play more with the rpm window between where the fuel cuts and where it comes back in, and then pull some timing in just that area if needed.

Did you reduce the Ceiling and Floor? The help file says the floor should be 100-150 below the ceiling.

[nafoo]

Originally Posted by E90SoFlo

Why isn't shiv a sponsor..

Autopay fail.

[OpenFlash]

Originally Posted by nafoo

Autopay fail.

Lol yep. I really need to set up an autopay through paypal

[GeorgiaTech335coupe]

Originally Posted by shiv@vishnu

What you really want is an ignition cut, not throttle cut. That way the throttle is open from the launch all the way to the end of the run. If you limiting revs by throttle closures, your boost with discharge and you'll have to spool up the turbo again between gears. I found this to be critical during the 1-2 shift especially.

This is also probably why you are still bogging at 4k rpm. Not sure exactly how great the XIs are at launching, but in my i with 285 drag radials, I would probably spin, dumping the clutch at 4k rpm at the drag strip.

I could be wrong though as I have never driven the XI, maybe it just grabs that much better than my I with DRs.

[rader1]

Originally Posted by GeorgiaTech335coupe

This is also probably why you are still bogging at 4k rpm. Not sure exactly how great the XIs are at launching, but in my i with 285 drag radials, I would probably spin, dumping the clutch at 4k rpm at the drag strip.

I could be wrong though as I have never driven the XI, maybe it just grabs that much better than my I with DRs.

It's almost certainly due to xi. 4K RPM launch is more than enough to broil my tires.
My schedule is freaking stupid right now and it'll probably be next week before.I.can.start really digging into ATR but I was expecting cool little tide bits like this and I can say so far I'm not disappointed. This is real tuning ladies and gents

[Carl Morris]

Sorry I accidentally pasted extra splooge into the title the first time...

Did some more experimenting over lunch on NLTS. It looks like the logic used is that when you're against the rev limit in gear zero, and then you release the clutch in a new gear you have to momentarily let off before the gear 0 rev limit is cleared. It doesn't seem to matter how I do it, if I'm at WOT when I've let off the clutch pedal I'm stuck at 4k until I "burp" the throttle. It also appears that in a single gear (such as first) this does not happen, which is why I don't hit the artificial limit in first after I've released the clutch.

Originally Posted by shiv@vishnu

What you really want is an ignition cut, not throttle cut.

I'll take a log and see what it's doing. I just assumed it was cutting fuel and spark rather than throttle...I frequently forget that the throttle is ECU controlled :-).

Originally Posted by nafoo

Did you reduce the Ceiling and Floor? The help file says the floor should be 100-150 below the ceiling.

Yes, I reduced them both to just above and just below 4k for this experiment.

Originally Posted by GeorgiaTech335coupe

This is also probably why you are still bogging at 4k rpm. Not sure exactly how great the XIs are at launching, but in my i with 285 drag radials, I would probably spin, dumping the clutch at 4k rpm at the drag strip.

I could be wrong though as I have never driven the XI, maybe it just grabs that much better than my I with DRs.

Yeah, XI. At the dragstrip with no 2-step I've been flooring it at the first yellow at idle and launching on the third yellow at close to 5000rpm. It works OK but it's not nearly as consistent as a 2-step. I didn't expect 4000rpm to be perfect, but it was a nice low starting point. If Shiv is right and it's cutting throttle on me, then it's not going to be nearly as useful as I'd thought.

[nafoo]

Did you try to see if you were building boost while reving?

[Carl Morris]

No, I'll have to log. I don't have a real boost gauge. Maybe I could look on the Cobb live display but I've never tried to do that before.

[nafoo]

I made a "2-step" map, I'll check it out after work

[OpenFlash]

Originally Posted by Carl Morris

Sorry I accidentally pasted extra splooge into the title the first time...

Did some more experimenting over lunch on NLTS. It looks like the logic used is that when you're against the rev limit in gear zero, and then you release the clutch in a new gear you have to momentarily let off before the gear 0 rev limit is cleared. It doesn't seem to matter how I do it, if I'm at WOT when I've let off the clutch pedal I'm stuck at 4k until I "burp" the throttle. It also appears that in a single gear (such as first) this does not happen, which is why I don't hit the artificial limit in first after I've released the clutch.



I'll take a log and see what it's doing. I just assumed it was cutting fuel and spark rather than throttle...I frequently forget that the throttle is ECU controlled :-).



Yes, I reduced them both to just above and just below 4k for this experiment.



Yeah, XI. At the dragstrip with no 2-step I've been flooring it at the first yellow at idle and launching on the third yellow at close to 5000rpm. It works OK but it's not nearly as consistent as a 2-step. I didn't expect 4000rpm to be perfect, but it was a nice low starting point. If Shiv is right and it's cutting throttle on me, then it's not going to be nearly as useful as I'd thought.

Unfortunately, it only retards timing and cuts throttle. Which is why you are not able to build boost (or hold boost between gears) with it.

[Dave W.]

OK I'm keeping my DSM for a little longer...
Keep us updated on progress!

[Carl Morris]

OK, well now I have to be more apologetic to Cobb for my frustration with them not coming out with it sooner. Looks like more of a code change than I'd originally expected.