endurance racing with an LS engine

Most(if not all) stock LS cams are in the 180/190 duration range.  With 222/232 I'm shifting at a whopping 6200rpm.  I wouldn't exactly call that revving it to the moon.  With the old 232/240 It would make power out 6800.

More displacement is the easy ticket to reliability.  Look at what comes in heavy duty trucks.  Big cubic inch, low revving, low compression, and they will go 300,000 miles while getting beat on everyday.

Keith Tanner said:

In reply to racerfink :

I was a mechanic on the Mazda race team for the 2006 Thunderhill 25. We were running the brand new NC Cup Car prototype, and it became apparent that the transmissions were good for 200 laps before they broke a shift fork. So we patched up the cars and told the drivers to stay in 4th after that.

Fastest time of the race (for one of our cars) was set at 3 am by a driver only using one gear - although I suspect he might have slipped it into 5th on the back straight. Still, it was smooth and zen and in the zone instead of trying to drive the wheels off the car.

Sometimes it is faster to drive the course and not the car 

Patientzero said:

Most(if not all) stock LS cams are in the 180/190 duration range.  With 222/232 I'm shifting at a whopping 6200rpm.  I wouldn't exactly call that revving it to the moon.  With the old 232/240 It would make power out 6800.

Duration is only one dimension.  Stock cams have very wide LSAs for smooth idle and low load drivability.  Intake valve closing is the main factor in determining when the powerband is.  A cam with more duration and a tighter LSA can have a remarkably similar intake valve closing, or at least not so far out there as the duration difference alone might imply. 

The tighter LSA will make idle rougher and the engine will be more exhaust sensitive, but that is typically something people actually WANT from a cam 

SKJSS (formerly Klayfish) said:

I don't run an LS, but have been heavily in endurance racing for a really long time.  Tons of LS swaps.  Keep it cool, keep it oiled.  I believe the 5.3 LS redlines at 6k.  I'd shift at 5k.  Yeah, you may give up .5 sec per lap.  However, it's an endurance race.  If you want it to last 15 total hours, show it mercy.  The 6M in the Cressida I race redlines around 6500 I think, but I shift between 5000-5500.  We finish top 10 each and every time unless we have an issue (not engine related most of the time).  

Prime example.  Just a few months ago at New Hampshire.  Out of 120 cars, we had the 25th fastest lap overall, yet finished 6th overall and won our class.  We started 7 laps down as a "penalty" for being in class B, and had a power steering belt jump off, which took about 7 minutes of track time.  Had we started even and not had the belt come off, we'd have finished 4th or 3rd overall.  

As I said, keep the engine oiled and cooled.  Show it mercy.  You don't need to go nuts with any power upgrades.  Key to success...  

This endurance racing requires mechanical empathy.  If you don't have it, you break.  My dad swears to this day they didn't win their class at LeMans for this very reason.  One of the drivers (that I will not name) kept breaking transmissions.  Sure he set the fastest lap times in the car and in cars above them in class, but they broke.  And a much less powerful, much less capable, much more stock car won the class.  It didn't break.  I can probably find a good article to the story I read once. 

Pete. (l33t FS) said:

Patientzero said:

Most(if not all) stock LS cams are in the 180/190 duration range.  With 222/232 I'm shifting at a whopping 6200rpm.  I wouldn't exactly call that revving it to the moon.  With the old 232/240 It would make power out 6800.

Duration is only one dimension.  Stock cams have very wide LSAs for smooth idle and low load drivability.  Intake valve closing is the main factor in determining when the powerband is.  A cam with more duration and a tighter LSA can have a remarkably similar intake valve closing, or at least not so far out there as the duration difference alone might imply. 

The tighter LSA will make idle rougher and the engine will be more exhaust sensitive, but that is typically something people actually WANT from a cam 

In my example both cams have the same LSA at 112.  While you are correct, a tighter LSA is going to be much harder to tune on a stock LS computer or EFI in general.

Here is the cam I have chosen.  I feel like it had good power without huge lift, or the need for high revs.  I got the btr springs they recommend for this cam, and look forward to getting this car together.  Any thoughts on the cam?

N

I little tight on the LSA but I'm sure it will work just fine for what you're doing.

The LS9 is an easy choice for a light car--it will rev to 6800 just fine, and make power (cheap, too).  In terms of the cam you chose, lift is basically the same for it and the LS3, however LSA is not (makes no real difference, especially if you're road racing).  I could have set you up with an unused LS3 cam and springs, but too late . . .