402 w/ L92 heads... another wrong cam
08-18-2009, 08:18 PM
#41
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.
If my "setup" was in a more suitable "drag car" it would pick up quite a bit-not 135mph but considerably better.
Can only guess at what the cam would do with this setup in a stroker.
11-19-2009, 07:10 PM
#42
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Latest update.... Okay here are the changes:
Kooks 1 7/8 headers w/ cats
LS3 intake and Manley race exhaust valves
Stage 2 port job on the intake manifold done by me!
Not sure what did what, but I'm happy with the results... I will be heading back to the dyno once I do more tuning.
Kooks 1 7/8 headers w/ cats
LS3 intake and Manley race exhaust valves
Stage 2 port job on the intake manifold done by me!
Not sure what did what, but I'm happy with the results... I will be heading back to the dyno once I do more tuning.
Last edited by 1999vetteroo; 11-23-2009 at 11:41 AM.
11-23-2009, 11:50 AM
#45
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Not sure if I understand the question. I went with bigger headers and better flowing exhaust valves to increase efficiency. At this point I'm more focused on beefing everything up to handle the power. I.E. trans brace, built rear end etc. After that, I'll push the envelope north of 550rwhp. I still have things I can do to achieve that!
Last edited by 1999vetteroo; 11-24-2009 at 12:30 AM.
11-23-2009, 02:10 PM
#46
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The package that you invest yeild you a respectable power range to the tire from a 402 ci (6.6 Liter) and the massive torque...
Speaking for my self, this is an achievement for the 402 ci... It made more to go with the L92 head for their potentail since comparing cost vs results is ranked real high... Really GM engineers done their work well...
As for my question, I read about L92 head from other threads, that it has exellent intake flow (+300 cfm @ 0.600") in the stock form but the exhaust flow is not to the level of the intake, thus I'm assuming massaging the exhaust by porting will help this issue or it will make it worse...
Buy the way, do you have plan to use vaccum pump to pump the rwhp up more...
MRT
Speaking for my self, this is an achievement for the 402 ci... It made more to go with the L92 head for their potentail since comparing cost vs results is ranked real high... Really GM engineers done their work well...
As for my question, I read about L92 head from other threads, that it has exellent intake flow (+300 cfm @ 0.600") in the stock form but the exhaust flow is not to the level of the intake, thus I'm assuming massaging the exhaust by porting will help this issue or it will make it worse...
Buy the way, do you have plan to use vaccum pump to pump the rwhp up more...
MRT
11-24-2009, 12:46 AM
#47
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I have heard of guys porting the exhaust side only on L92 heads and seeing nice results. I will eventually send mine off to TSP or Advanced Induction for a full port job on both sides. I had my heads flowed right out of the box and they flowed 323cfm.
As far as the vacuum pump, I'm still reading into that one. There isn't alot of information out there on it. Might be worth doing though....
As far as the vacuum pump, I'm still reading into that one. There isn't alot of information out there on it. Might be worth doing though....
Last edited by 1999vetteroo; 01-01-2010 at 11:00 AM.
11-24-2009, 07:01 AM
#48
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Going from lgm 1 3/4 to ARH 1 7/8 my 402 picked up 16.x rwhp and 7.x rwtq. Power everywhere too, not just peak.
(posted in response to a previous comment on there 402 didn't pick up any power when switching to a larger primary)
(posted in response to a previous comment on there 402 didn't pick up any power when switching to a larger primary)
11-24-2009, 06:33 PM
#49
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Yep Doug, the car feels stronger all the way through. Now I just need to work on the diff before it explodes at the track. What did you end up doing to your diff this time around?
11-25-2009, 07:06 AM
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Ron sent me a replacement pair and now she is running perfect. Kicking *** and taking names. How convenient though, she's running great, and its time to put her up for the year. I plan to drive her this weekend and then who knows. As long as a couple sunny days are in the forecast with no snow I'll drive the car. Scary how much harder she pulls on the COLD air.
11-26-2009, 12:08 AM
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A mid 230s intake seem to work well to make excellent topend power in these. xfi lobes make good power, the 228 intake works good, maybe bump the lift a bit and run more split to help it hold on up top. My setup runs what ppl say as overcammed. Its yet to prove itself but it has a MS4 cam running at a 107 ICL with 11.2:1 comp and its still running 32 deg of lead. It seams very torquey through 3-4000rpm surprisingly probably cause I advanced it. The thing is it has made excellent power in other L92s but as some pointed out a smaller intake may get within 10hp of this cam but a lot better on fuel. The overlap effect also may not be affective as a small cathedral port which thrives on overlap to get intake speed, To much of it with L92s doesn't seam to work, to much volume and it just blows right through, which is where however the small ex has an advantage. Not to much airspeed is generated with a huge intake tight lsa and a 260cc port. Cut the intake duration down and reduce overlap accordingly and airspeed starts to rise dramatically which is why so many ppl get freak results with small cams. If you are going to run bigger cams ensure you increase the comp and have enough ptv clearance to get the intake cl where it should be. And even then it still maybe slightly trial and error. I feel that there a few cams that work nicely especially in LS3s cam only, the 230 xfi intake lobe is a gem not to big not to small fast ramp rate couple with a 234-236 exhaust. 114 lsa works nice and good streetability.
