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-   -   Ported WRX Cylinder Heads ?? (

Bully-Perf. 06-08-2009 11:36 PM

Ported WRX Cylinder Heads ??
Just throwing this out here to see what type of interest their may be....If I’m in the wrong thread please let me know and I will move it right away.

My name is Mike and I am the General Manager at Bully Performance, LLC based in Detroit, MI. We have been doing some development work on a WRX head here in the shop and wanted to know if this may be something of interest to the WRX tuners here in this forum?

We have over 20 years of cylinder head development experience and have worked with big name racers here in the Detroit area. Again this is to just gage interest only. I have been searching on the forum and online and have only come across a couple ported heads with big valves from cosworth.

My questions at the moment are: Who is porting heads for these types of vehicles? Is high quality affordable port work something that would be of interest here? Also, would any one be interested in doing some dyno testing with some of our ported heads to show actual gains?

We have all the best machines available to do high quality work...Serdi, Sunnen, Bridgeport, Super flow (Flow Bench) ECT...

If anyone has input please post and I will respond with answers to any questions you my have.

Best Regards,

Bully Performance, LLC

baller_v24 06-09-2009 08:48 AM

Ported heads would always be a nice upgrade. It's not exactly practical for me because this is my daily driver and I live in TX. I think realistically, people with some serious issues that require pulling the engine would benefit from this the most.

It's always good to have a second option besides just cosworth as well. You could also post in nasioc, as it is one of the biggest subaru communities out there. [url=]NASIOC[/url]

Bully-Perf. 06-09-2009 09:55 AM


Thanks for the forum lead. I really think that more Subaru owners would probably upgrade their heads if an affordable ported head was offered. I have seen cosworth stuff out thier for around the $ 5,000.00 + range ! Hell I wouldnt even look at purchasing heads for that price unless I had some serious cash flow.

Thanks again for the input! !Thumbs Up

anyone else ?


sleepr 06-10-2009 12:20 AM

I think those of us with (older) 2.0L engines who end up going the hybrid route (2.5L block with 2.0L heads) would be intrigued with this option with respect to what kind of improved numbers (HP & Torque) could be put down. Unfortunately for us 2.0L owners, I suppose your economy of scale in the US is probably going to be achieved with 2.5L heads, as there are more factory 2.5L motors than 2.0L motors in the US now.

Just my .02 !Thumbs Up

Bully-Perf. 06-11-2009 08:12 AM


Thanks for your input. We are not opposed to doing any and all cylinder head work for this community. I am going to post pictures along with before and after flow data tonight on the casting we ported. Is their a preferred casting number for the 2.0L heads so we can pick up a casting and do some development?

Best Regards,


sleepr 06-11-2009 08:38 AM

I am unable to provide that info for you...hopefully someone else can chime in with the numbers you're looking for. thanks to whoever does...

dumdum 06-11-2009 10:18 AM

[url=] - Cobb Tuning 2.0 WRX Cylinder Heads Stage 3[/url]
[url=]Four Cylinder Heads[/url]
[url=]Crawford Performance[/url]
[url=]Tech Works Engineering Subaru Cylinder Head Porting and Combustion Chamber Modification[/url]
[url=]PURE Tuning Subaru Street / Competion / Racing Porting & Polished Cylinder Heads[/url]
[url=]:: Crucial Racing Systems - The parts you need for the performance you want[/url]

jed344 06-11-2009 11:38 AM

i agree for people gonig the 2.5 block with 2.0 head route ( I plan on in the future) that ported heads would be benifical

Bully-Perf. 06-11-2009 07:42 PM

Bully Performance Cylinder Head Info & Pictures
5 Attachment(s)

First I want to thank everyone that gave some input on this subject.!Thumbs Up Here is some pictures of our test head and portwork. Please feel free to ask questions and leave feedback.


Bully Performance, LLC

Bully-Perf. 06-11-2009 07:45 PM

more pictures
5 Attachment(s)
More pics:

dumdum 06-11-2009 07:58 PM

[quote=jed344;224504]i agree for people gonig the 2.5 block with 2.0 head route ( I plan on in the future) that ported heads would be benifical[/quote] Ported/polished heads would be beneficial for for just about anybody and any engine.Not just someone doing a 2.5L swap.

Bully-Perf. 06-11-2009 08:11 PM

Stock Flow Numbers
Here is the flow data we came up with for the stock head.

[B][U]Stock Intake:[/U][/B]

.100 - 81

.200 - 171.5

.300 - 235.5

.400 - 250.6

.500 - 255

[B][U]Stock Exhaust ( Strait ) [/U][/B]

.100 - 83.5

.200 - 146.3

.300 - 173

.400 - 182.5

.500 - 187

[B][U]Stock Exhaust ( Dog - Leg ) [/U][/B]

.100 - 80

.200 - 138

.300 - 156

.400 - 164

.500 - 170

Bully-Perf. 06-11-2009 08:19 PM

Bully Performance Flow Numbers
Here is the flow data after we modified the ports. This head has our custom developed valve job angles, port work and [B][U]stock size valve diameters of 1.420" x 1.260" [/U][/B]

[B][U]Ported Intake Runner[/U][/B]

.100 - 84

.200 - 172

.300 - 250

.400 - 291.2

.500 - 306

[B][U]Ported Exhaust (Strait )[/U][/B]

.100 - 77

.200 - 158

.300 - 203

.400 - 220

.500 - 231

[B][U]Ported Exhaust ( Dog Leg )[/U][/B]

.100 - 80

.200 - 152

.300 - 196

.400 - 215

.500 - 224

Now all of this data was done on a super flow 600 bench @ 28" of H20.

jed344 06-11-2009 11:26 PM

yes dumdum i was though helping to reinforce sleepr's comment though that doing it for not just 2.5 heads but 2.0 heads:)

baller_v24 06-12-2009 02:46 PM

That work looks pretty flawless, nice work. It's an option I would def consider if I ever decide to go that route. !Thumbs Up

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