1g versus 2g/Evolution 1-3 head question answered

[Bimmubishi]

well, as best as I can answer it.

To my surprise the Galant/1G head produced better dyno numbers. The catch is that I can't tell you if it's the head or the manifold but all other things being the same mechanically we tuned my car today with the Evo II head and it made 480 or so whp on our Dyno Dynamics dyno and it made 490 with the 1g head and intake manifold.


Both heads and manifolds were unported and stock

Other observations:

Possible that the exhaust manifold is a flow restriction (obvious)

The Evo head had a small advantage in my modifying the exhaust for external dump thus reducing pressure in the exhaust system; still fell short.

 

Cool. I don't recall which turbo you were running.

 

[2of9]

great numbers. IIRC, i think the 1g head has bigger intake ports than the 2g head. But doesnt the Evo intake manifold flow better than or the same as our usdm 1g intake manifold?

 

[Bimmubishi]

We'll never know which manifold is better through dyno testing since they need to be attached to their respective heads. : (

Garfield- PTE56 trim with external gate.

The logical step would be to upgrade the manifolds. Maybe next year. I'm going to be running ALS this year and I think that the stock mani is the only one that will hold up.

 

[RedTwo]

So about 10 hp difference? Not all that much for something (the evo head) that every man and his dog (on the internet) has written off as being a rubbish head with small ports, etc, etc.
Any truth to the theory people have about higher velocities/better spool with the evo head?
Is this with a 35mm restrictor?

For what it's worth, a guy was selling a ported Evo 2 head on Trademe a few months ago with the following flow bench numbers (cfm):

In Ex
212.7 186.8 Stock
264.5 223.6 Ported

 

[G]

B, if you come across a evo 3 head i would like to buy it.

 

[Bimmubishi]

G- I think 1-3 are the same but I'm not positive. They all look the same.

I'm probably going to stick with this head for a long time. I'll probably get it ported for next year. I want to try some 290 tomei cams in it this year.

Yeah, red, only 10hp and this motor is fresh so maybe the numbers would have been identical with a broken in motor. Another thing is that I have a dogbox now which has a bit more rolling resistance than the standard box.

Top numbers aside the spool was a bit more latent with the Evo head and that was the real surprise. Hopefully we can fine tune things to make up for that.

 

[turbowop]

I've always thought that it was known the 1g head would make more peak power, but that the 2g or Evo 1-3 head would provide a better torque curve. Did your dyno results prove similar?

That is surprising that spool-up was slower. /ubbthreads/images/graemlins/confused.gif

 

[Bimmubishi]

Yeah basically lower power and slower spool. I'll post some graphs. Like I said though the drivetrain and fresh motor could be hurting things- not sure.

 

Do you have the dyno graphs? Peak numbers are only impressive if the rest of the curve works too. Those flow numbers the guy posted look about right compared to a 2G head I have. A little work to that Evo II intake would make it work better with that size turbo.

 

[3rdstrikedsm]

evo 1-3 heads are the same.