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Max rpm of LS1?


zook62

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I think this is the right section for this...

Does anyone know how far an LS1 will happily go before it pisses itself all over the road? I have a good breathing set of heads, cam, and hardened pushrods that will gladly go 6500+, but I'm too much of a sissy to let it do so without knowing the limit of the bottom end. If you've seen any of my posts you probably know that I bought the car as-is from a dealer, so what I know I have mostly found myself. Very little past on. I currently shift at 6500, but I have not yet found a rev limiter. Not sure if it was lifted to a point or removed completely. I know stock is around 6100/6200, so that has obviously been kicked.

Either way I'll probably wait til I get it to LPM to get their opinion before I get anymore ambitious, but I'm just curious if anyone knows. Thanks.

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I wanna say that Nic set my rev limiter at 7300 or so, and my car is set up real similar to yours. I typically shift at 6800-7000 when I'm gettin on it and it hasn't scattered itself yet...

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I think the weak point is the valve springs (total guess) from my memory/reading. they start to flutter and the valve does not close properly and that causes a cascade of issues.

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I think the weak point is the valve springs (total guess) from my memory/reading.

they start to flutter and the valve does not close properly and that causes a cascade of issues.

:withstupid Were the springs upgraded when the cam was done?

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Mine were... He bought his car done already, but I assume they were. It's pretty rare to find someone that did a cam and didn't do springs...

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Mine were... He bought his car done already, but I assume they were. It's pretty rare to find someone that did a cam and didn't do springs...

:agree

The problem is that springs, especially ones used in conjunction with a cam and lots of time at higher RPM, are subject to earlier failure. Not knowing anything about the time/mileage/conditions and wanting to go high RPM, makes one think that replacing them now would be prudent.

Pretty much the same type of preventative measures taken when dealing with other maintenance items on a used car. i.e. brakes, lubricants, etc.

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If I remember correctly, the previous owner (barbiegirl826) said that she had reciepts from Xtreme Motorsports in Tempe that did the work on the engine. You might contact them to see what all was done to your Vette.

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Mine were... He bought his car done already, but I assume they were. It's pretty rare to find someone that did a cam and didn't do springs...

:agree

The problem is that springs, especially ones used in conjunction with a cam and lots of time at higher RPM, are subject to earlier failure. Not knowing anything about the time/mileage/conditions and wanting to go high RPM, makes one think that replacing them now would be prudent.

Pretty much the same type of preventative measures taken when dealing with other maintenance items on a used car. i.e. brakes, lubricants, etc.

Ya, mine have about 20,000 miles on them, and I'm thinking of changing them by the end of the year...

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Mine were... He bought his car done already, but I assume they were. It's pretty rare to find someone that did a cam and didn't do springs...

:agree

The problem is that springs, especially ones used in conjunction with a cam and lots of time at higher RPM, are subject to earlier failure. Not knowing anything about the time/mileage/conditions and wanting to go high RPM, makes one think that replacing them now would be prudent.

Pretty much the same type of preventative measures taken when dealing with other maintenance items on a used car. i.e. brakes, lubricants, etc.

Very good point. And yes I believe the previous owner listed a comp cams dual valve spring kit. I had a valve cover off not long ago but i forgot to check if there was that second set. But you're right in that if I can't prove how long they've been in there it would be a good idea to have them replaced before pushing it too far.

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Also taking it much further might not be optimal anyways depending on the camshaft. It would be pointless taking it further than say 6800 if its falling off before then. Give me a call at the shop and I can set up a time for you to swing by for Nic to take a look at it.

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Also taking it much further might not be optimal anyways depending on the camshaft. It would be pointless taking it further than say 6800 if its falling off before then. Give me a call at the shop and I can set up a time for you to swing by for Nic to take a look at it.

That is definitely on my to-do list. I gave you guys a call right after I got the car but had to cancel as we just had our new one arrive 3 weeks ago. I'll call you guys as soon as I can get up there

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Where you shift really needs to be based on your dyno graph, your trans gearing, and your rearend gears. Sometimes even though power is dropping off, you want to go a little farther before you shift to put you in a better part of your torque/hp curve. In the case of a turbo car, sometimes short shifting is better if you gearing isn't optimized for the turbo. Based on what you describe and if you do indeed have dual springs, I wouldn't shift it past 6800. You don't necessarily need new springs. You would need to test them all though.

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Where you shift really needs to be based on your dyno graph, your trans gearing, and your rearend gears. Sometimes even though power is dropping off, you want to go a little farther before you shift to put you in a better part of your torque/hp curve. In the case of a turbo car, sometimes short shifting is better if you gearing isn't optimized for the turbo. Based on what you describe and if you do indeed have dual springs, I wouldn't shift it past 6800. You don't necessarily need new springs. You would need to test them all though.

I havent yet gotten it to a dyno, but I can tell it would gladly continue to rev and pull. It may be past its peak at 6500, but it's not what you would call "falling off". I'll check out the springs again and get it to a dyno soon to hopefully answer my questions. I'll post results when I get them.

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  • 2 weeks later...

Also taking it much further might not be optimal anyways depending on the camshaft. It would be pointless taking it further than say 6800 if its falling off before then. Give me a call at the shop and I can set up a time for you to swing by for Nic to take a look at it.

That is definitely on my to-do list. I gave you guys a call right after I got the car but had to cancel as we just had our new one arrive 3 weeks ago. I'll call you guys as soon as I can get up there

Cheaper just to call Nic and put it on a dyno. No need to over pay at LPM.
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