Originally Posted by Chris@HPTuners
Anyway we can determine exactly what the PCM looks at when it switches to the P/N limiter? If I shift at/near my P/N Limiter, I hit it. When I'm above the limiter, I don't notice anything on shifts.
Anyway we can determine exactly what the PCM looks at when it switches to the P/N limiter? If I shift at/near my P/N Limiter, I hit it. When I'm above the limiter, I don't notice anything on shifts.
We are obviously working with two completely different animals. The V6 works one way, the V8 another. I have been driving mine with this set up for a few weeks and have run into no problems.
When I am stopped, it is limited, when moving, it is not. So for the V6, once I leave the start line, my limit is 6300.
2013 Jeep Wrangler JK
3.6 V6
More MODs than Stock
2018 Ram rebel
5.7 Hemi V8
Stock
You can drive down the road at 50 mph, put your clutch in, and rev your motor past the P/N limiter? I can't.
That is correct. What type of car do you have?
2013 Jeep Wrangler JK
3.6 V6
More MODs than Stock
2018 Ram rebel
5.7 Hemi V8
Stock
I tried it on two '00 f-cars.
V6 works differently than V8.
V6 limiters
--------------
P/N: selector in Park, or in N and speed < 5mph
Reverse: selector in Reverse
In Gear: none of the above
note: P/N limiter is disabled if CASE learn is being performed.
If you have ETC then you have an ETC RPM limit as well.
V8 limiters (ignoring the startup limiter)
-----------------------------------------------------------
P/N cutoff RPM: selector in Park or N (A4 only)
Cutoff RPM vs Gear: A4 in gear or M6
Bad VSS cutoff RPM: VSS DTC set
The vs Gear table works for both A4 and M6. Those with M6's and vehicles with a clutch pedal switch fitted will select the P/N limiter in the vs Gear table when the clutch is depressed.
The PCM uses RPM/MPH ratios to determine current gear for M6's and also will select the P/N column if the RPM/MPH ratio is not within any of the "in gear" ranges. (ie. this is a cost saving way of determining if the clutch pedal is depressed without requiring a switch).
For A4's the PCM uses a combo of the current gear and the selector switch to determine gear.
I'll put this stuff in the help files.
Hope it helps,
Chris....
I count sheep in hex...
I finally made it to the track and had a chance to test this idea.
WORKS GREAT.
Three runs, here are my 60 foot times.
2.149
2.184
2.181
Street tires and a V6.
They were the easiest launches I have ever had. No thinking, just let it bounce off the limiter and let the clutch off and floor it. A monkey could have done it (kind of like an automatic ;D)
It sure works for the V6. Maybe someone can figure out how to make it work on the V8.
2013 Jeep Wrangler JK
3.6 V6
More MODs than Stock
2018 Ram rebel
5.7 Hemi V8
Stock
Great Thread! 8)
I really would like to have this feature figured out for us T56 V8 guys.
IMGO, THIS SHOULD BE A TOP PRIORITY
WHY?
As far as I'm concerned, any feature that can pretty much guarentee us more consistent launches and likely drop .1 off our ET's will make as much difference to me as the entire rest of the suite, since (in my case) we may only gain .1-.2 off the tuning HP gains.
2002 Z51 C5 MN6 Coupe&&SuperMaxx Headers, Vararam, Ti Exhaust
Anyone ever have any luck getting this to work for us T56 / LS1 guys?
neat thread.
heh, so i can find it again:
2step 2 step revlimiter
soooo... lets say i add a clutch up switch to my 02 fbody setup (i currently dont use one) and i add a button inline with that to "arm" the setup... will that work?
if i have the clutch switch error DTC disabled, will it not look at it?
1991 Camaro Convertible with 02 LS1
These posts are REALLY OLD, but did anybody get this to work on their M6 LS1?
2000 ECSB Sierra, with a lot of tuning to do.
On my 2001 ZO6 that I shift at 7000 rpm, I set the Fuel Cutoff vs. Gear table to 7000 cutoff/6999 Resume for 1st thru 6th & 5500/5499 P/N. As soon as I step on the clutch to powershift, the 5500/5499 limiter cuts in. Don't need a clutch switch. Works great!
Russ Kemp
So let me get this straight. Lets say you're in 1st, you accellerate up to 7000rpm and then when you step on the clutch it cuts fuel until you're at 5500, and then you release the clutch when in 2nd?
What are the advantages of this? How is this like a 2 step?
2000 ECSB Sierra, with a lot of tuning to do.
Yes, I hold the gas pedal to the floor while shifting. The 7000 rev limiter is active with the clutch out and 5500 with the clutch pedal pushed in. If the trans is in neutral the 5500 rev limiter is still active. It would be nice to have a 3 step limiter to leave the line at say 2500 rpm with street tires.
Russ Kemp
Ok so I experimented with this last night and I must say the rev limiter the PCM provides is just way too violent. I was able to build 2psi at about 4000rpm, but not without the whole truck shaking. I don't recommend this for us V8 people. A spark cutoff would be the only way to go.
2000 ECSB Sierra, with a lot of tuning to do.
Russ,
Can you determine if the "ETC" limit works in your application or are you just using the "Normal" table.
EC
Always Support Our Troops!
I tried this on my 99 MN6 C5, it didn't work. I set the P/N cutoff to 2000 and the resume to 1999. Also verified that the PCM can see the clutch engaging and disengaging. All testing was done a 0MPH with clutch in and both in/out of gear....no luck. Also 'enabled' the ECT limiter, but it only has one master RPM cutoff (8000 currently) limit, so I can't see that helping much.
I did find out that if you set the 1st Gear RPM cutoff to 1K, it definately cuts off
Doug,
I almost forgot about your question! Anyway this works on my 2001 ZO6, but tried the same on a 2004 ZO6. On the 2004, the wot 1-2 shift worked, but the rev limiter cut in when in 2nd gear at 5750. Same thing on a 2001 Firehawk.
Russ Kemp
Back to the top one more time.
Finally getting close to figuring out my "perfect" launch. Now the problem is getting staged and getting to right RPM and steady before lights flash. Pro tree happens pretty quick.
Played with this a little today. ECT limiter doesn't seem to do anything (02 Z06), Cutoff RPM vs. Gear seems to do the trick though. Has anyone actually tried this with a WOT pass? Little concerned that fuel cutoff kicks in right when clutch starts in and I mean as soon as it moves downward. I set the limiter low 2400 off/2399 on and just drove normal, seemed jerky when shifting gears but I was shifting easy not rowing them. The clutch was catching but limiter was still cutting fuel because pedal wasn't fully released yet.
Maybe just need to try it but thought I would check to see if anyone else had scienced this all out before I go break my best stuff.
2002 Z06 LG Long Tubes, Spec 3+, HPTuners
1988 TransAm GTA - LS1 conversion, custom CAI, exhaust, LS6 Intake, Fuddle 3400, HPTuners
Trying to get this to work on my 01 SS M6(T-56) without any luck. Mine works like I want with the clutch in(4000), but also kicks in in 1st and 2nd@4000 also. 3rd and 4th work normally(6400).
It seems like it should work, but I tried it several ways between the RPM vs. Gear table, and the P/N cutoff.
Can this be done?
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