I need some advice on cams. I have an Airtrek, and the engine is basically an Evo 8, but I run an auto gearbox. I was looking at getting either GSC S2's or Kelford 272's, but have been advised with the auto that the power band will move too high and wouldn't work well with the auto. I was advised to go GSC S1's or Kelford 264's. Since they cost the same regardless of spec, it just doesn't seem right going to the smaller cam. From the advice I've been given, I should probably go with the smaller cam, but I'm after some feedback, especially from Evo GTA owners. Car specs are in my signature.

 

Aaron,

What would happen if one ran s3's on an fp black 2.0 stock block with boltons? Would it damage any parts? This is on an evo9. Or would there be more power than the s2s all around?

Thanks

 

We tried it on an VIII vs a IX with S2s and a Red. The VIII made 495whp at 30psi and the IX made 520. I have to think they were just too much for the combination.

 

Broham: What is your rev limit and current power/power band look like? I think the s2s are great cams for an black, good mid range power with enough room to breath up top.

as you are well aware, the s3s are more aggressive and will shift your power band higher in the rpm range. But seeing as that you have a built 2.0, I would imagine to can rev that bish pretty high (9k+?). With the S3s, you will not some low end loss, but potentially gain power on the top end.

is this a drag car or a street car? Why did you decide 2.0 vs 2.3 ? For a street car I would be inclined to stay s2s to maintain as much mid range/"low" end power as possible. but if your going down the 1320 or shooting for high numbers, the s3s would be a good switch.

in for Aaron's opinion as he is WAY more knowledgable than myself. Have you thought about STM's custom grind where they keep the specs a secret? they look pretty cool as well...

 

The revs wouldnt go past 8500 and this would be for street driving. I guess I'm saying if the low end loss is a little bit but the mid range and high are much stronger, is it worth the trade off?

Aaron, when you say the combination was too much do you mean the s3's are just too aggressive and not streetable unless you have a 2.4 like engine?

The question I should rephrase is why use s2s if the s3s will produce more power sacrificing lower end. What if I don't care about low end and just want the car to pull very hard once you are going past 4500?

Thanks folks

 

The biggest trap in the realm of cams is thinking that bigger is always better. This is faulty logic.

For starters, a stock, unported head cannot take advantage of everything S2s can deliver, much less S3s. A factory intake port stalls around 10.5mm lift.

Secondly, acceleration performance depends upon average (not peak) power through the gears. Narrowing the usable powerband by forcing power to the upper rpm ranges isn't necessarily a wise idea for stock block engine, with its rpm and power limitations.

Stick with a cam set that works with your head, in the rpm ranges where your engine/turbo can reasonably make power.

 

In this case I wish it was simple enough to just go bigger and gain more power, but the car will choke with factory head components. I'll stick with s2's until I have a better "breathing" setup. Thanks folks

 

Even with a better breathing head and built block, with that turbo and your desire to maintain solid street performance, you'll not outgrow the S2 cam set.

 

Greg,

Do you have a graph like this from a stock turbo VIII comparing the S1 vs. S2? That'd really drive a stake through this whole thread. I see the audience here being the stock turbo, mild bolt-on crowd; like me.

Thanks,

M<

 

^ BUT, would these cams do a similar thing on a stroker...?

 

Hi Guys, sorry for off topic but can someone share their S2 cams setting beside the factory setting from GSC?

Just wonder will it improve response if i advance 2~4 deg on the intake cam for my Gt3076r, Stock head, 8.5.1 comp pistons?

 

Yay MIVEC!

 

You want S1 to S2 on a stock turbo? I can find that sheet somewhere.

 

It would pick up even better with a stroker as the large motor needs bigger cams to be happy.

2-4 will hurt idle, help spool, then hurt top end.

 

Thank you Aaron...