Comp 918's on boosted motor
#1
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From: Visalia, California
Comp 918's on boosted motor
Wondering if 918 comp springs are going to work with an MTI stealth II cam and 15 or so psi of boost. Already have the 918's, not sure if I should sell/trade and upgrade to a better single-spring. Opinions?
#3
I ran 918's with stock heads/cam for a while on a ProCharged setup. They worked fine. I think I'd prefer a dual spring when using a larger cam though. The 918's are definitely good for the money.
#4
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From: Visalia, California
I hope it works out well for the rear mount. Had trouble spooling the T70 out back with the hotcam and short gears. Need taller gears, and wanted to get rid of the lope... Cops in this area are ****'s when it comes to that, and will have your car inspected. I read that the 918's were rated at .600 lift, but then I realized yeah, I'm under that, but... under boost won't it hang the valves? I hope the 918's work, def didn't want to go double spring on a street car.
#6
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From: Visalia, California
Originally Posted by Boostaholic
I don't know that there is much of a difference between N/A and F/I springs all other things equal?
#7
well supposedly pple who have used the 918's are commonly pple who upgrade to LS6 parts or pple with nicer aftermarket H/C setups, and i think i remember seeing alot of them revving the crap out of their cars with no valve float...
i think you should be fine with the 918's, like u said they're rated to .600, so keep using em..what are the specs on the stealth cam? just curious
i think you should be fine with the 918's, like u said they're rated to .600, so keep using em..what are the specs on the stealth cam? just curious
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#8
Originally Posted by 67Firebird455
Wondering if 918 comp springs are going to work with an MTI stealth II cam and 15 or so psi of boost. Already have the 918's, not sure if I should sell/trade and upgrade to a better single-spring. Opinions?
If shimmed to .050 within coil bind the 918's can handle damn near most cams with up to .620 lift these days. I just wouldn't throw them on a LSK lobe at all, or throw them on a big XE-R lobe without shimming them.
They will work wonderfully with that little cam and you shouldn't have to worry about valve float.
Nate
#9
was never sure but with the TTi street kit, at 15psi, it seemed I was getting valve float at 5500 rpms with the 918s. That was with a '01 z06 cam. I THINK i was because i couldnt trace it down as being an ignition prob but i would suddenly get massive misfires at that rpm. 13 psi and got no misfires. Just my experience which i know doesnt help
#11
dont know the specs of your cam but the this 222/228 .56whatever XE cam does just fine to 7000rpm @ 14psi with the single springs that came on these darts. They are similar to 918s, I read they are the same spring (made by PSI) as 918s but I'm not sure of that..
Either way they work for me, If I have to toss a 140.00 set of springs in once a year I'll deal with it
Either way they work for me, If I have to toss a 140.00 set of springs in once a year I'll deal with it
#12
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From: Visalia, California
Yeah, the stealth 2 is 224/220 @ .050 and .581/.581 lift. I just don't need major problems with the new motor, but also don't want double springs. *Keeps fingers crossed* Hope they work out.
#14
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I think at 15PSI you'd want to go to a dual spring. I am running CC918's right now at 5PSI with no probs (mods in sig), but the new heads I have to install have duals on them. I'll be upping boost to 8PSI then. I think 15PSI might be a bit too much for the 918's. Just my $0.02.
#15
Originally Posted by 67Firebird455
Yeah, the stealth 2 is 224/220 @ .050 and .581/.581 lift. I just don't need major problems with the new motor, but also don't want double springs. *Keeps fingers crossed* Hope they work out.
#16
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From: Visalia, California
Originally Posted by JAvenger007
When you mentioned lope, were you referring to the hotcam? How much of a lope do you get out of a hotcam with a rear mount? Doesnt it muffle a lot of it.
#17
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From: Visalia, California
Originally Posted by bboyferal
Why so against the duals?
#18
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From: Visalia, California
Originally Posted by Schantin
I think at 15PSI you'd want to go to a dual spring. I am running CC918's right now at 5PSI with no probs (mods in sig), but the new heads I have to install have duals on them. I'll be upping boost to 8PSI then. I think 15PSI might be a bit too much for the 918's. Just my $0.02.
#20
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From: Visalia, California
Originally Posted by Zombie
I floated 3 valves at 15psi on 918's with a 224/224/112 .567/.567 cam.
I now have a stronger springs but I don't know what they are.
I now have a stronger springs but I don't know what they are.