CAM Gear settings for GT35
#1
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CAM Gear settings for GT35
For those running CAM gears with the GT35, what do you have them set at? I know there are settings that help power up top, but was looking for something that would help down low, with minimal sacrifice on the top end (if it is even possible).
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Try a +2, +2, wont help your idle, but it shoule help to spool the turbo a bit sooner, but you will lose a little top end pull, but with the GT35, probably wont matter much as that sucker pulls hard anyways.
this is what i have read on here anyways.
this is what i have read on here anyways.
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Don't mean to hijack, but might as well make this a camgear advice thread. I'm planning a 272's, gt35/alky AEM EMS with stock internals project. What cam gear settings would work to move the tq curve DOWN? I don't care about sacrificing topend..it'll have more than the car can handle anyway with the alky/30psi boost. I'd just like to "street down" the curve to fight lag at all costs with the 2.0. I also don't care about how smooth the idle is as long as it doesn't stall. I'll be running external dump and a good open exhaust of course... I know tuning is the key but can my gears help?
#9
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Here is a repost of a recent point I illustrated:
For example, here's some recorded spool characteristics with my basic setup:
HKS 272s at -3/-3 = 23psi at 3400rpm
HKS 272s at -4/-1 = 23psi at 3900rpm
HKS 280s at +2/0 = 23psi at 3500rpm
So you can see that changes in cam timing can make a significant difference in power characteristics. Also note that such changes can make for larger peak numbers, but 'peakier' power curves.
. . .
Also, have a look at the graph posted by Razorlab about 3/4 of the way down in the same discussion: https://www.evolutionm.net/forums/sh...d.php?t=178407
What do you think?
For example, here's some recorded spool characteristics with my basic setup:
HKS 272s at -3/-3 = 23psi at 3400rpm
HKS 272s at -4/-1 = 23psi at 3900rpm
HKS 280s at +2/0 = 23psi at 3500rpm
So you can see that changes in cam timing can make a significant difference in power characteristics. Also note that such changes can make for larger peak numbers, but 'peakier' power curves.
. . .
Also, have a look at the graph posted by Razorlab about 3/4 of the way down in the same discussion: https://www.evolutionm.net/forums/sh...d.php?t=178407
What do you think?
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I had settled on trying -3-3 with the stock turbo or any small bolt on...but now my power greed is gonna jump to GT35 and I wanted to make sure the curve rules didn't change with the extra boost/power. I suppose they don't. -1+1 looks promising... I prob wont' have the dyno time to experiment. I'd like to get the word from guys who have "been there" so I can decide, set them and tune for the best. Your guys' experience could save me a lot of hassle.
Last edited by FlyNavy; Jan 13, 2006 at 06:21 AM.
#11
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No, -3/-3 would definitely not be the best setting for you. Consider the fact that the longer duration HKS 280s spooled virtually as quickly as did the HKS 272s because of the settings. Also compare Razorlab's charts that depict the HKS 272s at +1/-1.
Also, you didn't mention which cam set you have. A setting that works well for one may not be what you want with another.
Also, you didn't mention which cam set you have. A setting that works well for one may not be what you want with another.
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Sorry, I edited to add I'm running 272s seconds after I posted..you were too fast for me. I thought you yourself had best spool luck with the -3-3 setting. The +1-1 curve looks great but is not compared to any other 272 settings. Its just whooping up on stock cams which I already know. My 272's with stock gears are already a great mod. With the nature of the GT35, moving that curve down has new importance. So, I'm now leaning toward +1-1 pending more data.
#13
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And I agree with the +1/-1 setting for the HKS 272s if you want quickest spool from that turbo.
Why?
Because despite the long duration of the 272s, the graph shows they spooled quicker than the factory cams at the +1/-1 setting, with no loss of midrange torque or top end power. This defeats the argument that longer duration cams cause a drop in low speed power, which is largely determined by cam timing. The strong midrange characteristics of this setting will put more pressure to the turbo earlier, which is what you want.
Why?
Because despite the long duration of the 272s, the graph shows they spooled quicker than the factory cams at the +1/-1 setting, with no loss of midrange torque or top end power. This defeats the argument that longer duration cams cause a drop in low speed power, which is largely determined by cam timing. The strong midrange characteristics of this setting will put more pressure to the turbo earlier, which is what you want.
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Woo Hoo I have my answer. I'll locktite those badboys to +1-1 and go from there. How do you see it affecting idle? I LIKE a nasty idle as long as it never stalls. Right now my car is set to idle high and rich to keep it smooth-I hate WATCHING the fuel spit out the exhaust when sitting still. I'd rather it be lean and low. You think I can have a non-stalling aggressive sounding idle and not run so rich? I'll be using a certified EMS tuner.