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critique my cam design!!

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Old 08-29-2007, 12:17 PM
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Default critique my cam design!!

car:
2001 ws6 w/ m6, intake, cat-back exhaust, ls6 intake, 100 shot of spray

want to port heads (ls1 stock) and get head gasket (.041?) w/ tighter squish at the same time

personal needs/wants:
1. low end torque, max hp below 6k
2. no spring changes after initial install, not even interested in the chance of failure
3. will get efilive, but little concession on driving manners
4. emissions close
5. stock exhaust manifolds
6. no problems with pinging on typical fuel (91-93) and nitrous

in order to fulfill requirements:
1. 216/222 dur @.050
2. comp 918's and xe lobes (.561/566 lift)
3. 113 lsa, 111 ICL
4. -7 deg overlap
5. final valve events: IVO -3 BTDC, IVC 39 ABDC, EVO 46 BBDC, EVC -4 ATDC, so 46 BBDC for exhaust mani's and nitrous
6. final dynamic comp ratio: 8.26

i am currently in iraq, support the troops with your hotrod advice!

--SSG
Old 08-29-2007, 12:24 PM
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ASA cam with LS6 yellow springs.....
Old 08-29-2007, 01:16 PM
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ASA emissions legal??

a lift that a gm off-the-shelf spring is capable of??

more replies, please!
here is an opportunity to do your part in fighting the global war on terror!!

SSG
Old 08-30-2007, 01:07 AM
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ASA cam will not even be close to passing any emissions.

That cam you specced should work decent with the nitrous and stock manifolds. You should bump the exhaust lobe to 226. To get all the gasses out of the exhaust valve through the factory exhaust, you're going to have to hold it open longer than a standard split. Especially if you are spraying.. you're going to have more gas to expel. Going to a larger exhaust lobe won't effect your DCR, but it will open the exhaust valve sooner. You'll lose a little low end torque, but that's what the gas is for. Nitrous burns faster so that's another reason to open early. You will still have -5 degrees overlap at .050, easy to tune, and will pass emissions. It will drive very close to stock.
Old 08-30-2007, 07:15 AM
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good advice, i have been seeing alot of cas with 10 deg more exhaust duration and an earlier exhaust opening point.

thanks for pointing this out, Asmo

anyone else??

SSG
Old 08-30-2007, 10:53 AM
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Originally Posted by Asmodeus
ASA cam will not even be close to passing any emissions.

That cam you specced should work decent with the nitrous and stock manifolds. You should bump the exhaust lobe to 226. To get all the gasses out of the exhaust valve through the factory exhaust, you're going to have to hold it open longer than a standard split. Especially if you are spraying.. you're going to have more gas to expel. Going to a larger exhaust lobe won't effect your DCR, but it will open the exhaust valve sooner. You'll lose a little low end torque, but that's what the gas is for. Nitrous burns faster so that's another reason to open early. You will still have -5 degrees overlap at .050, easy to tune, and will pass emissions. It will drive very close to stock.
I do not quite agree on more exhaust duration with juice. I would get a higher lift on exhaust that yes.
Old 08-30-2007, 02:02 PM
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hey, predator, thanks for chiming in!

most of what i have learned about these numbers comes from you and patrick, so i am happy you are offering your 2 cents.

if i can keep the exhaust tight, it will probably offer a little more torque. nitrous is used sparingly, when someone has just completely asked for it....

what about different lobes/spring life?? what is a different lobe that might offer more performance?? perhaps OMC with dual springs and shimmed?? more flow from an aggressive profile??

SSG
Old 08-30-2007, 11:51 PM
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You can run XER lobes with 918 springs. Send me a pm when you are going to buy EFI Live, I might have a deal for you. Stay safe and keep fighting the good fight.
Old 08-31-2007, 09:32 AM
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Use XFI Lobes

I just used a XFI/XE-R

224/222 .609/.581 117LSA (Super Stealth)
Old 08-31-2007, 11:49 AM
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predator:

i see alot of cams that approach .600 lift, but which ones are more gentle on springs??

XE-R, XFI, OMC??

and if so, why?

would double springs be more appropriate in these cases? (100 bucks difference for maybe 5-10 ft-lbs, does this sound right??)

SSG
Old 09-01-2007, 07:15 AM
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Don't be afraid of lift, Patriot Gold dual Kit will do the trick
Old 09-01-2007, 10:20 AM
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how long will the Patriot Gold's last with that type of cam?
Old 09-01-2007, 10:46 AM
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I ran the PRC dual springs for 43,000 miles on a .598 lift cam and they were still good when they were replaced...
Old 09-01-2007, 01:36 PM
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ok, try this:

1. 215/222 dur @.050
2. patriot duals, OMC int, XE-R exh lobes (.600/.581 lift)
3. 113 lsa, 112 ICL
4. -7.5 deg overlap
5. final valve events: IVO -4.5 BTDC, IVC 39.5 ABDC, EVO 45 BBDC, EVC -3 ATDC, so 45 BBDC for exhaust mani's and nitrous
6. final dynamic comp ratio: 8.32

looks initally like a cheatr cam, but has less duration on the exhaust.

the whole thing is just tighter than before but with much more flow on both ends




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