Rev limit hit before Desired Limit

Guys I just got off the dyno tuning a car . The car made great power everything seemed good until we tried to rev the car a bit more. I had been reving the car to 6400 without an issue. Now that I am trying to rev it to about 6800 the car seems to be hitting the rev limit at 6450 or so. Can you guys check the tune and let me know if you see anything that could be causing it.

The only things i see is that the MAF gets maxed out. I know there is a patch for it but I believe the patch is already applied. Unfortunately I do not have a log as my computer died while trying to capture the log. Also the map is maxing out but I doubt that has anything to do with it. But I do see the Maf maxing out on the car

This is an LS2 motor original car with a crate lsx motor. I know he is using some type of lingerfilter signal changer for the crank to be able to run the car with that motor

Is the car boosted? On some cars if the MAF maxxed out they roll back over to zero HZ. It'll feel like a rev limiter, but it's not. Just a severe lean spike.

If not, the tune usually has three different sections for controlling the rev limiter such as Extreme Cutoff, cutoff versus RPM, and startup seconds versus RPM. You'll find your problem in one of those three tables, and yes they're all located in the same section.

Can't view your tune right now or else I'd point it out to you.

-Rob.

Also make sure you aren't maxed out duy cycle wise...

Can't open the file because I'm on my phone, but I would bet its the startup limiter.

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Originally Posted by dsmlights

Guys I just got off the dyno tuning a car . The car made great power everything seemed good until we tried to rev the car a bit more. I had been reving the car to 6400 without an issue. Now that I am trying to rev it to about 6800 the car seems to be hitting the rev limit at 6450 or so. Can you guys check the tune and let me know if you see anything that could be causing it.

The only things i see is that the MAF gets maxed out. I know there is a patch for it but I believe the patch is already applied. Unfortunately I do not have a log as my computer died while trying to capture the log. Also the map is maxing out but I doubt that has anything to do with it. But I do see the Maf maxing out on the car

This is an LS2 motor original car with a crate lsx motor. I know he is using some type of lingerfilter signal changer for the crank to be able to run the car with that motor

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I don't see any obvious causes. You really need a log file for others to view, preferably with a good wideband setup. It's not the startup rev limiter or any other obvious ones I can see, so I would guess it's something going on, maybe a lean spike as IDRIVEAG8GT said.

Also, how are you deciding the RPM it's rev-limiting at. The tach often doesn't keep up with the engine. If the scan says 6450 that's different, but many times I see a car someone thinks it say shifting at 6500 and it's hitting 7K.

I don't exactly know where to start.

But I'll start here.

Your VE table is set to 0.
You are running a 2 bar speed density custom operating system but still have maf enabled
Boost VE is set to 0

Start by setting up the tune for 2 bar speed density such as its set up for, the move on to issues from there, not the other way around.

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Originally Posted by Bill@HPTuners

I don't exactly know where to start.

But I'll start here.

Your VE table is set to 0.
You are running a 2 bar speed density custom operating system but still have maf enabled
Boost VE is set to 0

Start by setting up the tune for 2 bar speed density such as its set up for, the move on to issues from there, not the other way around.

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Bill although I am running a SD tune i should still be able to do a maf only tune if I wanted right ?

^ Bill was asking you why you upgraded since there wasn't much point in doing so.

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Originally Posted by dsmlights

Bill although I am running a SD tune i should still be able to do a maf only tune if I wanted right ?

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Not necessarily.

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Originally Posted by IDRIVEAG8GT

^ Bill was asking you why you upgraded since there wasn't much point in doing so.

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The car is boosting about 16 psi so the 2bar map was maxing out. I decided to go with the MAF. Also it was just easier to dial in. The car came already upgraded with the 2Bar

Pretty sure the E40 supports up to a 2.5 bar sensor so its not a sensor limitation as 2.5 bar should cover 16psi without issue.

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Originally Posted by Bill@HPTuners

Pretty sure the E40 supports up to a 2.5 bar sensor so its not a sensor limitation as 2.5 bar should cover 16psi without issue.

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Bill, on an E40 can you run an LS9 MAP? (max 312 kPa)

No. LS9 MAP has a negative offset value, and a linear value greater than 256kPa, neither of which the E40 will accept.

so what is the right MAP to use for E40 in this case?

I build one that fits the range that the E40 is capable of.

I had the same issue on the std OS for some weird reason. Tripe checked all the values. Could it be that using fuel cutoff over spark cutoff could cause this?