402 w/ L92 heads... another wrong cam
Your making very nice power and I like the early peak which makes it a great DD setup.
As for Cam.It works very good and the 112+4 helps alot but I'm sure there is a Cam out there that would increase the power from 3k to 4.5k while extending the torque/hp to a higher rpm while not giving up anything over the existing Cam.This is ussually where the split comes in with a longer exhaust duration.
I'll go through my dyno graphs when I have time next week and show the Cam/power differences with a bigger split.
As for Cam.It works very good and the 112+4 helps alot but I'm sure there is a Cam out there that would increase the power from 3k to 4.5k while extending the torque/hp to a higher rpm while not giving up anything over the existing Cam.This is ussually where the split comes in with a longer exhaust duration.
I'll go through my dyno graphs when I have time next week and show the Cam/power differences with a bigger split.
It seems like the LS3/L92 heads have great potential. I'm having a hard time planning my build because I want to go with a 408 and I would love to get some WCCH L92's. But that means i have to wait to get the 408 and my LS1 with have to go headless because I rather avoid the hassle of trying to sell stuff.
The other option would be to get some TFS 220 as cast heads and have them ported for the 408 but I dont know if they'd make power up top like the L92's.
The other option would be to get some TFS 220 as cast heads and have them ported for the 408 but I dont know if they'd make power up top like the L92's.
these L92 heads seem to be a puzzle for alot of people, in regards of which cam to match them to. i know there are a few different theories as to what kind of split the heads will like. im sure the experts will weigh in...
What heads? I'm betting that with the "weak" exhaust flow numbers of the L92's (weak as in such a vast difference in the flow compared to intake) a larger header and exhaust that is a perfect match of flow and scavenging will yield a great result. In other words, I suspect 1 7/8th headers will see a bigger gain on these L92 heads than the traditional cathedral port heads.
As for Cam.It works very good and the 112+4 helps alot but I'm sure there is a Cam out there that would increase the power from 3k to 4.5k while extending the torque/hp to a higher rpm while not giving up anything over the existing Cam.This is ussually where the split comes in with a longer exhaust duration.
I'll go through my dyno graphs when I have time next week and show the Cam/power differences with a bigger split.
I'll go through my dyno graphs when I have time next week and show the Cam/power differences with a bigger split.
I get so tired of all of these people saying big split, L92 specific this, when in fact those miracle cams generally just make about the same (if not less) power that a somewhat "off the shelf" cam like the VRX5 or the one I run from Ed Curtis. Nothing but a bunch of marketing and bs.
The only cam that really is worth talking up and about for L92 heads, that is a "secret" cam, is the one that Ed and VA Speed used in the GTO a few weeks ago that made 508/441 on a 6.0 bottom end. Those were extraordinary results.
If they told everyone the specs would be out and people would just have it custom ground and skisp goin to VA speed and LG
Last edited by smok'nZ; Aug 16, 2009 at 04:06 PM.
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Verdad Gallardo Links to specific examples? And are the comparisons at least close to apples to apples? I.E. everything pretty much the same BUT the cam?
http://www.ls1gto.com/forums/showthread.php?t=286447
Give you and example. 3rd car on the list has same cam I have only car is an M6-a traditional split, we will call it an off the shelf Ed Curtis cam, because you can call Ed and buy it and it was not developed for use with L92 heads. 7th car on the list and considerable lower in power, runs one of those "LS3 specific" cams from a very, very, well known shop.
What do most of you guys consider a "big split"? Im just curious as I am doing a 408 with L92 heads (CNC ported), 10.8:1 comp., and a TSP Giant cam, with the intentions of making over 500 rwhp. There seems to be lots of experts on the L92 cam, but the dyno's and track #'s tell the story.
This thread is the best "apples to apples comparison" as they are all 6.0 GTO's with L92 heads.
http://www.ls1gto.com/forums/showthread.php?t=286447
Give you and example. 3rd car on the list has same cam I have only car is an M6-a traditional split, we will call it an off the shelf Ed Curtis cam, because you can call Ed and buy it and it was not developed for use with L92 heads. 7th car on the list and considerable lower in power, runs one of those "LS3 specific" cams from a very, very, well known shop.
http://www.ls1gto.com/forums/showthread.php?t=286447
Give you and example. 3rd car on the list has same cam I have only car is an M6-a traditional split, we will call it an off the shelf Ed Curtis cam, because you can call Ed and buy it and it was not developed for use with L92 heads. 7th car on the list and considerable lower in power, runs one of those "LS3 specific" cams from a very, very, well known shop.
, lol. I must say though that I've done some reading on the L92 heads. The 7th car you mention does have the huge split that a lot of guys are saying is the key to to the L92 heads, but it's lacking the higher LSA guys are also saying is needed. And the exhaust lift is considerably lower than the intake, suggesting the lobe is not as aggressive as the intake. I believe what some of the "experts" are saying is that an engine needs around 11.0:1 compression (v. the 11.5:1 and up of cathedral ports) in order to run higher timing, a bigger split on the exhaust with intake duration in the mid 230's, and a slightly higher LSA than usually used will bring optimum results.
Since the list does not include cam lobes used, compression ratio, timing and the factor of dyno differences, it's hard to make a concrete conclusion based off that. I'm not saying that the list isn't worth anything, or that you are wrong in the assumption of a "normal" cam split is fine. It's just hard to get anything absolutely concrete from the list. It is great to see that regular split cams are working just fine on their setups.
Just goes to show that there will still be some more "experiments" and theories before these heads and combos are figured out. As it sits I don't think anyone is really wrong one way or another on that list. Besides, someone has to be doing something right to get a stock cubed automatic GTO with budget heads to hit 120mph trap speeds.
GM High-Tech came out with a article a long time ago that used a Livernois stage 2 cam with stock L92 heads and upgraded valvesprings...that put out 502HP 6,300RPM /465TQ 5,100 RPM...
What do most of you guys consider a "big split"? Im just curious as I am doing a 408 with L92 heads (CNC ported), 10.8:1 comp., and a TSP Giant cam, with the intentions of making over 500 rwhp. There seems to be lots of experts on the L92 cam, but the dyno's and track #'s tell the story.
I must say though that I've done some reading on the L92 heads. The 7th car you mention does have the huge split that a lot of guys are saying is the key to to the L92 heads, but it's lacking the higher LSA guys are also saying is needed. And the exhaust lift is considerably lower than the intake, suggesting the lobe is not as aggressive as the intake. I believe what some of the "experts" are saying is that an engine needs around 11.0:1 compression (v. the 11.5:1 and up of cathedral ports) in order to run higher timing, a bigger split on the exhaust with intake duration in the mid 230's, and a slightly higher LSA than usually used will bring optimum results.
I'm right in the thick of this...I just finished my 408 part 2 with L92/ls3 heads. I did get the CNC TSP heads since they seem best bang for the buck. With only 150miles on it and my first setup was LS1 style heads I only got 455/455. Yeah my Patriot2 heads didn't flow what these LS3 do. So this was a no brainer decision. Cam is another story. Since I'm a numbers guy for a living, numbers and how they relate make perfect sense to me. That said if I had a shop I'd run several setups but I don't. I'd like to see something like a 228/238 610/620 on a 115lsa all these numbers are ish...I think these are the ballpark 500rwp cam grinds w/ supporting mods and a over all good starting point. I'm NO expert and we all know how much BS is said here. This is why I'm sticking with my cam specs below and see what happens. If anything, I wish my int dur was lower and lsa higher, even 116. We'll see soon. Now if I could just get my intake to fit right I'll be fine! Don't ask, I started that one on another thread...
Ha. And I like that PBANDPKGTO guy in the middle of the list. A4 and a considerable higher trap speed than some of those other M6 guys with higher HP....wonder who that is , lol.
Just goes to show that there will still be some more "experiments" and theories before these heads and combos are figured out. As it sits I don't think anyone is really wrong one way or another on that list. Besides, someone has to be doing something right to get a stock cubed automatic GTO with budget heads to hit 120mph trap speeds.
, lol. Just goes to show that there will still be some more "experiments" and theories before these heads and combos are figured out. As it sits I don't think anyone is really wrong one way or another on that list. Besides, someone has to be doing something right to get a stock cubed automatic GTO with budget heads to hit 120mph trap speeds.
And just for the record, I am NOT saying that a "big split L92 specific cam" won't work. I just get tired of people, from "cam designers" to people that don't even have L92 headed cars, coming on here saying "yeah for L92 heads you need a bigger split, blah, blah, blah, blah" when this is not necessarily the case. And in a lot of cases these cams produce average #'s both at the dyno and on the track.
You don't need a wide lsa to make good numbers. It seems that just getting the valve events close - specially on the intake side - you can make good numbers The key seems to be keeping the intake smaller than a cathedral head build, A better intake manifold MAY change the rules a bit but that remains to be seen.
Just my $.02 - but what do I know.
Just my $.02 - but what do I know.
I'd like to see some info from someone who has one of these 500rwhp monsters who also traps around 135mph. I want to build one with my new (to me) 2000 Z/28 but my old white car went 123-127mph with a 346 cid NA so I would hope to much more mph than that with L92 heads and a stroker.