I did alot of research on both and most threads are very old. I would never go larger than a green or 18k Turbo. So whatever cams i choose needs to work well with stock Turbo or 18K maximum. I was fast spool and have fun in the first three gears. I would be happy with 380-400whp on a dynojet.

Currently my Evo X is making 322whp 320wtq on 91pct at 25psi and also have a high boost tune pushing 30psi with snowperformance stage 2 meth kit, but didn't have the chance to dyno it. It does feel like a 350whp 350wtq at 30psi, but i will verify that later.

If i choose to go with cams, im thinking either Kelford stage 1/2 OR Cosworth XM1. Not sure if i need springs with them, but my builder told me to get him 1mm larger valves with it so he can port the heads and intake manifold while he is in there. So most likely i will be getting springs as well.

If i choose to with witb 18K turbo, i would need a larger fuel pump and at least 1000cc injectors.

Eventually i will do both once i get bored with the power gains, but i want to choose one now.

So my question would be, which one should i go with first? Cams with everything ported or just a bolt on 18k turbo with fuel supporting mods?

 

Gsc s2.

Id go with the cam install first.
You can install cams springs and retainers with the cylinder head still in place with correct tools.

If this is a evo x you should invest the port job money in something else. I think john bradley is making 1000+ stock ports.

 

Yes its an Evo X. I didn't see alot of reviews on S2 on Evo X.

 

18k turbo hands down. FP has them on holiday pricing right now, $200 off I believe. I just picked one up and received it the other day. I plan on doing cams as well. But I will be doing GSC S1's. Talk with English Racing and they'll inform you why they're the best option. I'm doing S1's cause I don't want to chane the valve springs. My goal is similar to yours, a really fun street car. I don't need to rev to the moon. I'm running E85 though so I have ID1300 injectors and a DW300c pump. I'm hoping after the turbo and cam install I'll be upwards of 475whp on E85.

 

Whoa - thanks for the 18k tip. What manifold are you going to use for the 18K?

 

I think 18k is a direct replacement to the stock turbo so it bolts directly to the stock exhaust manifold.

 

S2's, and similarly big cams, with stiff springs cause issues with the exhaust mivec in the X.

Do S1's now, you'll pick up 15-20whp on the stock turbo. And get the 18k later and you'll have the perfect street setup.

 

I just say that because MAP says the stock exhaust manifold is bound to crack - but they also sell the solution so....

 

I have the MAP investment cast manifold

 

How does the S1 compared to the Cosworth XM1 or Kelford S1?

 

They're not just saying it to push their product. It is a known fact that the Evo X exhaust manifold will crack. It is not a matter of if, but rather when. They developed a product because of cracked manifolds

 

Kelford-a's are very mild. In my opinion they're not even worth doing, but that is just me. Kelford-b's are more inline with the GSC S2. Cosworth MX1's are a popular cam for the Evo X but they're a lot more expensive than the GSC stuff and they make the same gains as the GSC S1

 

No springs needed with the above cams?

I saw 1mm larger intake valves and 29mm exhaust valves from GSC as well. If i do that i might as well go with something larger than S1 or Kelford a.

Is increasing the valves size worth it?

 

After reading alot more in the forum, i think i should go with a Turbo upgrade and keep the stock cams for much better gains.
Now which turbo to go with is another research topic, but 18k and green are on the top of my list for fast spooling turbo that are direct replacement. I still want to use my Akravopic downpipe.

Any other turbo that competes with these two please tell me so i can research them further.

 

I would just go with the 18k. IMO is the best bolt on Turbo option for a street car. Designed by FP and made by MHI. So you get a killer Turbo with OEM reliability. The only other bolt on Turbos I would suggest are the Garrett stuff.