I think I need a retune.. Levels off at 3k RPM.
05-02-2007, 08:00 PM
#1
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Join Date: Jan 2005
Location: N Falmouth MA
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I think I need a retune.. Levels off at 3k RPM.
Ever since the recent LS6 intake and cat delete. I have noticed that the power seems to level off at about 3k rpm. -odd for an LS1. I have a LOT of low end TQ, but it seems to stop pulling as hard about 3k rpm.
When I give it 1/2 to 3/4 throttle in 4th at about 2k rpm, the speedometer climbs like crazy. after about 3k rpm, it seems to level off.
Ideas? Since my LS1 Edit, I deleted my cats, EGR, AIR and added an LS6 intake. My last retune was also at 21k miles. She now has 40,400 miles.
That LS6 intake also added a LOT of TQ, but seemed to have increased slightly when I deleted my cats.
When I give it 1/2 to 3/4 throttle in 4th at about 2k rpm, the speedometer climbs like crazy. after about 3k rpm, it seems to level off.
Ideas? Since my LS1 Edit, I deleted my cats, EGR, AIR and added an LS6 intake. My last retune was also at 21k miles. She now has 40,400 miles.
That LS6 intake also added a LOT of TQ, but seemed to have increased slightly when I deleted my cats.
Last edited by Bayer-Z28; 05-02-2007 at 08:30 PM.
05-02-2007, 09:09 PM
#7
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Really trying not to hijack but I've noticed the same thing after my LS6/header/exhaust install. Where is the extra vacuum line? I may have missed it. I actually don't recall plugging anything after I deleated the AIR/EGR.
05-03-2007, 07:50 AM
#8
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05-03-2007, 07:02 PM
#10
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^ 2000. I'm not worried about the low end power... It's that lack of high end that confuses me.
My dyno graph shows my TQ peaks at about 4500. 320RWTQ at 2k rpm, but why does it feel like soo much more and so little at higher R's???
I'll have to do a WOT 4th gear run this weekend out in the desert. Going to try to get it re-dyno'd and re-tuned soon too.
There is a T in the back of the LS6 intake, next to the MAP sensor. You can remove the T if you delete the AIR system. One vacuum line goes to that air system 'diverter valve' type thing.
My dyno graph shows my TQ peaks at about 4500. 320RWTQ at 2k rpm, but why does it feel like soo much more and so little at higher R's???
I'll have to do a WOT 4th gear run this weekend out in the desert. Going to try to get it re-dyno'd and re-tuned soon too.
There is a T in the back of the LS6 intake, next to the MAP sensor. You can remove the T if you delete the AIR system. One vacuum line goes to that air system 'diverter valve' type thing.
Last edited by Bayer-Z28; 05-03-2007 at 07:29 PM.
05-03-2007, 09:09 PM
#11
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Join Date: Jul 2002
Location: Bay Area, CA
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Change your fuel filter, clean you air filter. How old are the plugs etc etc. 
I noticed it not pulling so hard up top a few months ago. I did the above and it felt like new again.
Only true way to tell if you're not pulling ok though would be to get a dyno run in somewhere.
I noticed it not pulling so hard up top a few months ago. I did the above and it felt like new again.
Only true way to tell if you're not pulling ok though would be to get a dyno run in somewhere.
05-04-2007, 07:53 AM
#12
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Join Date: Oct 1999
Location: Inside Uranus
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^ 2000. I'm not worried about the low end power... It's that lack of high end that confuses me.
My dyno graph shows my TQ peaks at about 4500. 320RWTQ at 2k rpm, but why does it feel like soo much more and so little at higher R's???
I'll have to do a WOT 4th gear run this weekend out in the desert. Going to try to get it re-dyno'd and re-tuned soon too.
There is a T in the back of the LS6 intake, next to the MAP sensor. You can remove the T if you delete the AIR system. One vacuum line goes to that air system 'diverter valve' type thing.
My dyno graph shows my TQ peaks at about 4500. 320RWTQ at 2k rpm, but why does it feel like soo much more and so little at higher R's???
I'll have to do a WOT 4th gear run this weekend out in the desert. Going to try to get it re-dyno'd and re-tuned soon too.
There is a T in the back of the LS6 intake, next to the MAP sensor. You can remove the T if you delete the AIR system. One vacuum line goes to that air system 'diverter valve' type thing.
I don't see anything wrong with it. Take it to the track instead of trusting your ***-o-meter 
05-06-2007, 09:11 AM
#14
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Join Date: May 2000
Location: Chesapeake, VA USA
Posts: 501
I know it sounds dumb, but the linear HP progression and absolute smoothness of the LSx may be tricking you. By all means, put it on the dyno again, or run it at the track, but those mods shouldn't have caused a drastic change in the powerband.
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