Hi Guys,

Have a issue I'm puzzled about, recently did some changes to my s2000, Fitted a 4piston cnc ported head as well as a Skunk2 ultra series intake which has also been ported by 4piston. (K series intake which we made an adapter for the f20c ) Currently making less power on the same boost. No difference in spool, Last tune it made 801hp at 32psi with stock head and stock intake. Head and intake change ended up with 786hp at 34psi. Running the same amount of timing. We lost about 40 newton meters as well. Both days on the dyno the temperature was about the same.

Trying to figure out what the issue could be was hoping to gain a bit of power at the same boost level. What do you guys suspect the issue could be, I was told i need to go with a bigger turbo to see the advantages of the improved flow, which honestly i think is bullshit, I might be wrong...

Setup;

AFI front mount Manifold
Precision 6870 T4 1.32Ar
Cp 9.1cr
IC piping 3inch ex 3.35 inch in
Skunk2 Ultra 4p ported, 5.5 litre plenum
skunk2 90mm throttle
e85 fuel

 

I am not surprised...

check out this thread. "Stock unported head..."
https://www.s2ki.com/forums/s2000-fo...1168059/page3/

seen it on many occasions on these engines in particular it's a waste of money to port the head.

 

Well in theory, more flow means more power on less boost because the air is moving through the motor more quickly and not backing up to create boost. So if your seeing less power on the same boost clearly you've got something backing up. I didn't think Velocity was that much of an issue with boosted motors but you can deffently over port and over cam an N/A motor and loose power. The F series heads flow the same as the heavily ported (by Team 4 pistons) K series heads, without porting. But I figured add boost and it would help... hmm That said that loss was like a 2% loss. That could have been dyno, conditions, tires etc.

Sell the head and intake to someone doing a 2.7 stroker.

 

Have you talked to Luke? I'm curious to know what he has said about that beings he has one of my heads at the moment.

 

Yes i have mailed him, he did say i should switch to the stock intake and see what happens from there. So i might just try that.

 

I'd call that good advice.

 

That's hard to believe that you lost power, did you check for boost leaks with a boost leak tester?

 

I understand what you saying but i doubt a stock intake is not going to be a restriction at +-1000hp, I'm not saying that its 4pistons port work at all, just trying to figure out what I'm doing wrong, could the 90mm throttle be to big or the plenum volume or maybe i need a bigger cam? This is what i'm trying to figure out

 

I have personally had customers request I make their turbo manifolds a smaller diameter to get more velocity going to the turbo and no joke this results in increased hp at the same boost (obviously with some adjustments in the tune). Not saying that would be beneficial here, but there are just so many variables.

I am with MrSideways....would be interesting to see what the stock intake would do.

 

Can I see your dyno comparison?