Stock LS6 Engine problems at 7000rpm?
Thread Starter
Instructor
Joined: May 2007
Posts: 134
Likes: 0
From: Irvine CA
Stock LS6 Engine problems at 7000rpm?
Would like to hear if anyone has actually had stock LS6 engine failures of any sort with a 7000rpm rev limiter. Also interested in hearing success stories (2years, 7k once a day, mileage, etc).
Please no speculation, please no "I was told X". Just facts.
-M
Please no speculation, please no "I was told X". Just facts.
-M
Last edited by idlingmike1; Dec 13, 2007 at 05:46 PM.
Race Director
Joined: Jan 2006
Posts: 10,554
Likes: 33
From: Not on either liberal coast.
The stock rev limiter is 6,200 rpm, so you're thinking about a tune to raise the limits?
Melting Slicks
Joined: Dec 2004
Posts: 2,677
Likes: 0
From: I have to return some videotapes
I agree though, that the stock dyno sheets I've seen show that the power curve drop past redline. Hopefully someone else can chime in to answer the OP's question.
Race Director
Joined: Jan 2006
Posts: 10,554
Likes: 33
From: Not on either liberal coast.
:o I misspoke about the Z06 rev limiter. I found this past discussion and accepted the first reply I read as gospel...
http://forums.corvetteforum.com/show...06+rev+limiter
http://forums.corvetteforum.com/show...06+rev+limiter
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Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
The tack also doesn't keep up with the actual RPM of the motor, it lags. Two issues are the already mentioned valve springs and then the rod bolts are not up to task either.
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
I would not know why anyone would raise the stock rpm limiter from 6700 rpm on a STOCK LS6, unless you WANT to damage the engine so you can rebuild. 
As stated before, you don't make any more power and you are beyond your rod bolts and valves safety margin. 
Those ARE THE FACTS, you CAN choose to ignore them, but your engine WILL suffer.
As stated before, you don't make any more power and you are beyond your rod bolts and valves safety margin. Those ARE THE FACTS, you CAN choose to ignore them, but your engine WILL suffer.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
the LS6 engine was tested for 100 hours at 6900 rpms with no problems.
Many of the T1 race engines are tuned to 7100 so they can run 7000 rpms with out problems or bumping off the rev limiter
I have my car set to 6750 as I found no benefit above that rpm level
Many of the T1 race engines are tuned to 7100 so they can run 7000 rpms with out problems or bumping off the rev limiter
I have my car set to 6750 as I found no benefit above that rpm level
Burning Brakes
Joined: Aug 2000
Posts: 894
Likes: 1
From: Bethel Township Ohio
I ran my stock 97 Ls1 with a 7200 Rev limiter for 2 years about 20k miles, mostly on the track after the first year I did replace the valve springs with 918's (there wasnt much available at the time) The car did have all the bolt ons but the longblock was stock. The engine still ran fine and looked new inside when we pulled it out, I still have it sitting around. I would not worry about 7000 at all other than the valve springs, the stock LS6's will work although not ideal and you should replace them often.
Burning Brakes
Joined: Aug 2000
Posts: 894
Likes: 1
From: Bethel Township Ohio
I would not know why anyone would raise the stock rpm limiter from 6700 rpm on a STOCK LS6, unless you WANT to damage the engine so you can rebuild. As stated before, you don't make any more power and you are beyond your rod bolts and valves safety margin.
Those ARE THE FACTS, you CAN choose to ignore them, but your engine WILL suffer.
As stated before, you don't make any more power and you are beyond your rod bolts and valves safety margin. Those ARE THE FACTS, you CAN choose to ignore them, but your engine WILL suffer.
On some tracks with stock gearing it is a huge advantage not to make an upshift and then immediately downshift it will gain more time to stay in the same gear even though you are beyond peak power and torque.
It is a huge benefit to the auto-x guys
with Dale
Melting Slicks
Joined: May 2004
Posts: 2,502
Likes: 4
From: cincinnati ohio
It is an advantage in either auto-x or on a road course. I am with Dale too, as I have a '03 Z06 with a stock long block that I have had since new and routinely buzz it to 7300 rpm.......I do replace valve springs on occasion as I have to use stock LS6 springs in that particular car. Another area of weakness that people here are not mentioning is that the stock early timing chain will ot stand up to this rpm for long periods of time ( ask the T1 guys about this ). I have updated my chain to the 04-later (LS2) chain with dampner. No timing chain likes repeated hammering on the rev-limiter, regardless of which chain you are using no matter who it is from. Chain failures @ +7k rpm are NASTY....
Running the engine that high of an rpm is an advantage to not have to make the high-speed corner entry downshift ....the upshift is never the problem. Additionally I have known a few drag racers be suprised by shifting higher than their peak HP rpm.... It helps up-shift recovery into the next gear by being higher in the next gears torque peak (rpm).
BTW....My '03 car only looses 11 rwhp from its peak @ 6400 to the 7300 rpm rev-limit.
I never "hold" my car on the rev-limiter though.
Running the engine that high of an rpm is an advantage to not have to make the high-speed corner entry downshift ....the upshift is never the problem. Additionally I have known a few drag racers be suprised by shifting higher than their peak HP rpm.... It helps up-shift recovery into the next gear by being higher in the next gears torque peak (rpm).
BTW....My '03 car only looses 11 rwhp from its peak @ 6400 to the 7300 rpm rev-limit.
I never "hold" my car on the rev-limiter though.
Melting Slicks
Joined: Sep 2003
Posts: 2,458
Likes: 105
From: Northville Michigan
The GM Powertrain Engineers stated in their early presentations on the LS6 engine that in order to reliably exceed the 6,600 rpm rev limit they would need to improve the connecting rod bolt.
Katech sells such a bolt: http://www.katechengines.com/street_...etail.php?id=5
Katech also sells the best timing chain and gear set. See their web site.
And finally, consider a set of improved valve springs, such as Crane's 144833-16, along with the proper retainers - 144661-16, Hardened spring seats - 144640-16
Good luck with your decision.
Katech sells such a bolt: http://www.katechengines.com/street_...etail.php?id=5
Katech also sells the best timing chain and gear set. See their web site.
And finally, consider a set of improved valve springs, such as Crane's 144833-16, along with the proper retainers - 144661-16, Hardened spring seats - 144640-16
Good luck with your decision.
Last edited by Pumba; Dec 18, 2007 at 05:11 PM.
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
It is an advantage in either auto-x or on a road course. I am with Dale too, as I have a '03 Z06 with a stock long block that I have had since new and routinely buzz it to 7300 rpm.......I do replace valve springs on occasion as I have to use stock LS6 springs in that particular car. Another area of weakness that people here are not mentioning is that the stock early timing chain will ot stand up to this rpm for long periods of time ( ask the T1 guys about this ). I have updated my chain to the 04-later (LS2) chain with dampner. No timing chain likes repeated hammering on the rev-limiter, regardless of which chain you are using no matter who it is from. Chain failures @ +7k rpm are NASTY....
Running the engine that high of an rpm is an advantage to not have to make the high-speed corner entry downshift ....the upshift is never the problem. Additionally I have known a few drag racers be suprised by shifting higher than their peak HP rpm.... It helps up-shift recovery into the next gear by being higher in the next gears torque peak (rpm).
BTW....My '03 car only looses 11 rwhp from its peak @ 6400 to the 7300 rpm rev-limit.
I never "hold" my car on the rev-limiter though.
Running the engine that high of an rpm is an advantage to not have to make the high-speed corner entry downshift ....the upshift is never the problem. Additionally I have known a few drag racers be suprised by shifting higher than their peak HP rpm.... It helps up-shift recovery into the next gear by being higher in the next gears torque peak (rpm).
BTW....My '03 car only looses 11 rwhp from its peak @ 6400 to the 7300 rpm rev-limit.
I never "hold" my car on the rev-limiter though.
7000 rpm would help tremendously in the PIR banked curve. i always want to hit 5th (143 mph) right before i have to slow down, i always say ..just few more rpm baby get those damn ferraris off my ***! if i could carry 4th to 7000 i could shave .25 second i bet!
now if i could only carry more speed in those turns!!!!! hehehe
