Why am I hitting the rev limiter?

[Blk02Ls1A4]

I started this threas over on Ls2,

http://www.ls2.com/forums/showthread.php?s=&threadid=410425

Could you all look at my log and tun file and try to tell me what is going on. I would really appreciate it.

[foff667]

link doesnt work.

[Blk02Ls1A4]

Fixed:)

[joecar]

I didn't see the log/tun files, but try this...

set the 1-2 WOT MPH to 37 MPH, and set the 1-2 WOT RPM to 5300 RPM and take a log; if it now shifts without hitting the RPM limiter, increment the 1-2 WOT RPM until it shifts at the RPM you want.

[Blk02Ls1A4]

http://www.ls2.com/forums/showthread.php?postid=6617593#post6617593

[eboggs_jkvl]

I see both the scan and tune files in that link. They are attachments.

[Blk02Ls1A4]

I didn't see the log/tun files, but try this...

set the 1-2 WOT MPH to 37 MPH, and set the 1-2 WOT RPM to 5300 RPM and take a log; if it now shifts without hitting the RPM limiter, increment the 1-2 WOT RPM until it shifts at the RPM you want.

I have been doing that, but the other way around. I had my shift at 6300 and then moved it to 6200, then again to 6100 as is in that tun file. I have now gone back to 6000 and 53mph. I still need to log what happens now that I am at 6000.

[joecar]

I have been doing that, but the other way around. I had my shift at 6300 and then moved it to 6200, then again to 6100 as is in that tun file. I have now gone back to 6000 and 53mph. I still need to log what happens now that I am at 6000.What I meant was: set the MPH and RPM low enough to trigger, and then slowly raise the RPM until your actual RPM is what you require (specified and actual may not match each other).

[jfpilla]

-It could be as joecar says.
-Also, the torque converter slips some amount. Probably 2-300 rpms
in your case, right at your shift point, which results in higher engine rpms
than is inputted to the trans.
-Your graph shows a lazy shift. That could be slipping.
-You should log tccslip, trans input and trans output.
-tccslip added to trans input should be around 10 rpms of engine rpms.
If engine rpms are much more you have slippage.

[SSpdDmon]

Yeah....don't set shift MPH so high. If you have stock gears, leave the WOT shift MPH or maybe even decrease it 1~2mph. Set your RPM about 300~400RPM below where you want it to shift. Make a few runs and see where you're at. Increase by small increments to get where you want.

Also, traction helps. Spinning tires are more likely to cause some rev limiter action. ;)

[Elowe65]

Question??? Why couldn't he set the WOT shift mph down way low like <30mph, then just worry about adjusting the wot shift rpm???

It is my understanding that both perameters have to be met in order for the shift to occur therefore setting the mph down low ensures you are just shifting based on rpm... Do I understand this correctly??

Obviously this wouldn't cure anything if the rev limiter is being hit due to the rpm (due to tccslip) being to high.

[joecar]

Question??? Why couldn't he set the WOT shift mph down way low like <30mph, then just worry about adjusting the wot shift rpm???

It is my understanding that both perameters have to be met in order for the shift to occur therefore setting the mph down low ensures you are just shifting based on rpm... Do I understand this correctly?? Yes, this is the idea, but you don't want to set it too low or the 2-1 Downshift WOT MPH will now be above this (meaning you may not get WOT 2-1 downshift).

Must keep D910 > D925.

[Blk02Ls1A4]

Update: Now that I have finally had a day off, I was able to do some more logging. With the shift set at 6000 the car finally shifted at 6400 rpms without hitting hte rev limiter. I have backed it down to 5800 rpms and hope that with the 400 rpm slip that it will put me at 62-6300 rpms. So... I guess it is better for now, it does seem like 400 rpms is a good bit late for a shift, so next I am going to get out and log the tranny input and output and tcc slippage and see what they say.

[joecar]

What is your WOT MPH now set to...?