Hey guys,

We just received the data on our WRX heads. It took about 3 pairs of heads (2 pairs destroyed :( ) and many hours of testing at the hands of an experienced (and certified) porting specialist but we finally did it!

We managed to make WRX heads flow about 10 to 15 cfm BETTER than the JDM V8 big port counterparts. With the smaller runner diameters and better flow rates, you will be looking at more flow at higher velocities. Bottom line? Since heads are where most of the top end gains come from these heads will make much MORE power :)

We will be testing these heads in the upcoming weeks on a stage 2 WRX. Stay tuned!

Here’s some pics:
http://www.gruppe-s.com/Subaru/subeng/heads1.jpg
http://www.gruppe-s.com/Subaru/subeng/heads2.jpg
http://www.gruppe-s.com/Subaru/subeng/heads3.jpg

These particular heads received the Gruppe-S port work with a 5-angle valve job.


Gruppe-S port work with a 5-angle valve job
$1250 labor using your heads



Regards,

Preston

Gruppe-S Engineering
29150 Simms Ct.
Hayward CA 94544

Phone: (510) 783-5300

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Question, how is the flow matched regarding the dog legged ports?

Visually not impressive, rookie porter. But i guess it is the results that count.
Dog legged port ex port is about a 5-6cfm diff. unported.

The person porting our heads is actually a certified porter from Mondello (sp?) technical school specifically in terms of engine porting. He has been porting import and domestic heads for many many years, and has several sub 8 second cars under his belt. I personally wouldn't consider his porting to be rookie, but I guess you may say so if you have been doing Formula One work for most of your life. :p

Cheers,

Gary
Gruppe-S

Awesome work Gruppe-S! what's the turnaround for this?

So you are saying better flow than a V8 head and still retain the stock valves??

subscribed

Anyword on the Stage 2 dyno results yet? I'm definitely looking into this.

Phat04WRX - PM sent

03MBP - Not yet

Thanks
Preston

i am also interested in this. are you guys going to do these with a core charge type deal so i dont have have my wrx immobile for a week or more while the work is being done?
Ryan

Hey Ryan,

Probably not because we would have to have a steady supply of used heads coming in. Theoretically we would only need to front the first set of heads and then we could keep on sending out the set we have reworked from the last customer. Unfortunately, that never seems to work. We tried to do exactly that with our tranny core exchange and no one ever sends those back.

Thanks,

Geoff

So what valves and cams are do you plan/recommed with a set up like this. I would think that with the cost of vales, cams, and assoc gear you would be well past the V8 head cost for a small gain in CFM... ????

bumpity..... any more info here????

I already have my WRX heads ready to go but it would be nice to see before and after dyno curves before I send it out.

I would simply be thrilled to see actual v8 STi flowbench data.....everyone states how great they are, but I've not seen any numbers.

How did you guys determine that they flow better than v8 heads?

Tell us what your WRX heads flowed.....260 cfm @ .400"/28"? 280cfm?

You're asking a lot of money to port a set of heads with a valvejob; give us an idea of how well they perform. :)

S.

Update?

Bueller?

^^^^ ditto

nice alturnative to the 3700 cosworth heads. but i need more info

and if we provided the cams/valvetrain (non stock)

would that effect the price any?

So I guess you guys are very proud of these heads... enough to not give us any info ;)

id love to see some actual scanned in or otherwise proven data. this would make life pretty nice :)

any bench flow sheets?...sorry for bringing back the long dead thread...just looking into heads at the moment.

From what I have read, and researched the best bang for the buck would have to be V8 heads.
You figure a P&P on an ej205 head being in the 1200.00 range and still need to buy cams, the V8 head just looks very good at that point.