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Old 08-05-2008, 05:59 PM   #1
frayz
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Default Help frayz with his build please. (Few questions for the pro's)

Hey guys.

A few questions

As some of you may know, im building a new motor for my bugeye. Im swapping out my 2ltr for a forged 2.5 that im building myself.

I'll be using my 2ltr heads, but before i fit them i will be having the combustion chambers modified to fit the 2.5's 99.5mm bore.

What i want to know is, what will i gain more from? Head porting or cams?

How much extra power will porting add to stock heads if nothing else is changed?

If i decide on cams will the Brian Crower BC0621 kit work in my 2ltr heads and will my AVCS still opperate correctly?
What sort of power can i expect from this setup and what other mods will net me the most gains?

As some of you know. Im from the UK and parts here are ridiculously expensive, so anyone that can help me out by shipping me some parts would also be greatly appreciated.


I will be using the following parts.

New EJ257 block
New EJ257 sti crank
Wiseco pistons
Piston rings
Carrillo rods
ACL big end bearings
ACL main bearings
OEM head gaskets
ARP 11mm head stud kit
RCM oil pump
New oem water pump
PE kevlar timing belt
NGK racing 8s
Phenolic spacers
Machined 2ltr STI heads with AVCS
JDM Spec C inlet manifold
Ceramic coated GTSpec Gen 2 headers
800cc injectors
Hyperflow top mounted Oil cooler
Turbocharger exhaust housing (8cm for my FP green)
Exedy hyper Compe-R twin plate clutch, billet lightened f/wheel
Breather/Oil separator
Converted an fuel rails
Parallel fuel system, hose fittings etc
Fuelab fuel filter

Cheers for reading, i hope you can answer my questions
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Last edited by frayz; 08-05-2008 at 06:06 PM.
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Old 08-06-2008, 10:59 AM   #2
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Nobody?
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Old 08-06-2008, 01:28 PM   #3
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which version STi version heads do you have (big port v7 spec C or just the normal version 7)?

what parts do you already have and what do you need shipped?
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Old 08-06-2008, 03:08 PM   #4
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Quote:
Originally Posted by Homemade WRX View Post
which version STi version heads do you have (big port v7 spec C or just the normal version 7)?

what parts do you already have and what do you need shipped?
Normal small port V7 heads mate.

I have everything that i have currently listed.

However im wanting cams and springs/retainers. Valves too at a good price but i think at my level the stock valves will cope okay.

What i want to know is, what will i gain more from? Head porting or cams?

How much extra power will porting add to stock heads if nothing else is changed?

If i decide on cams will the Brian Crower BC0621 kit work in my 2ltr heads and will my AVCS still opperate correctly?

What sort of power can i expect from this setup and what other mods will net me the most gains?

What are your thoughts buddy?
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Old 08-06-2008, 04:13 PM   #5
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I know the JDM heads use different sensors to pick up the cam position and can't recall off hand if they'll work (I still haven't played with JDM heads). Just to let you know, those cams are sold out as well.

I'd get cams and valves (address the seat throat too) before cams and port work...

I wouldn't open up the combustion chamber. Maybe do some deshrouding but I wouldn't bowl it out.

What kind of power are you trying to make? what turbo will you be running? You don't need port work unless you want some seriously big power, at which point I'd hope to see sleeves in the build

Last edited by Homemade WRX; 08-06-2008 at 04:21 PM.
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Old 08-06-2008, 04:17 PM   #6
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Quote:
Originally Posted by Homemade WRX View Post
I know the JDM heads use different sensors to pick up the cam position and can't recall off hand if they'll work. Just to let you know, those cams are sold out as well.

I'd get cams and valves (address the seat throat too) before cams and port work...

I wouldn't open up the combustion chamber. Maybe do some deshrouding but I wouldn't bowl it out.

What kind of power are you trying to make? what turbo will you be running? You don't need port work unless you want some seriously big power, at which point I'd hope to see sleeves in the build

Gonna be on an 8cm 3" FP green minimum.

Maximum of GT30 mate.

I meant de-shroud, not bowl out. Sorry.

Whats wrong with the seat throat as they are dude?
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Old 08-06-2008, 04:17 PM   #7
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Looking for a solid 450/450 at least
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Old 08-06-2008, 04:22 PM   #8
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that'll be PLENTY of head work for a 450/450...30R it though. The 2.5 will spool the green to fast to be happy supplying air for 450...unless its a high reading dyno
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Old 08-06-2008, 04:50 PM   #9
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Id do a GT30 in an instant mate however i have a problem

They only guys that make the rotated up/downpipes for RHD are RCM. They charge $1700 for them without a turbo or wastgate.

If i could get some from the states to fit id be okay but as yet, i cant afford to do it
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Old 08-07-2008, 10:53 AM   #10
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Why not do a stock mount GT30?

http://www.atpturbo.com/Merchant2/me...egory_Code=BCS

That turbo is a GT30R with a custom turbine housing that is modelled after the garret housing. I'm suprised you don't want to buy from the states as the the US dollar is worthless over there...
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Old 08-07-2008, 11:06 AM   #11
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Quote:
Originally Posted by frayz View Post
Id do a GT30 in an instant mate however i have a problem

They only guys that make the rotated up/downpipes for RHD are RCM. They charge $1700 for them without a turbo or wastgate.

If i could get some from the states to fit id be okay but as yet, i cant afford to do it
RCM is some of the best stuff on the market, 850 - 1000 is what they run over here for just the pipes. The company that did you Exhaust could make you some, they seem very capable!
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Old 08-07-2008, 12:23 PM   #12
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Quote:
Originally Posted by bluescoobywagon View Post
Why not do a stock mount GT30?

http://www.atpturbo.com/Merchant2/me...egory_Code=BCS

That turbo is a GT30R with a custom turbine housing that is modelled after the garret housing. I'm suprised you don't want to buy from the states as the the US dollar is worthless over there...
I do want to buy from the US dude, but you have LHD, i need RHD pipes for a rotated mount.
Will that hybrid perform the same a a genuine GT30?
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Old 08-07-2008, 12:24 PM   #13
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Quote:
Originally Posted by Token-Negro View Post
RCM is some of the best stuff on the market, 850 - 1000 is what they run over here for just the pipes. The company that did you Exhaust could make you some, they seem very capable!
$800-$1000 USD dude,

Im taking 800- 1000 GBP!!! thats like $2000!!!!!!!! just for the pipes!!
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Old 08-07-2008, 12:46 PM   #14
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you beat me to it with the drop in 30R...
Frayz, it is completely bolt in and works with factory (or any other oem placed) uppipe and downpipe...as for the power limit because of the sizing, I'm not sure and have never run one.
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Old 08-07-2008, 04:21 PM   #15
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Is it actualy going to offer me much more than an 3"/8cm green?
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Old 08-07-2008, 06:52 PM   #16
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Quote:
Originally Posted by frayz View Post
Is it actualy going to offer me much more than an 3"/8cm green?
49lb/min vs. 52lb/min

i would take the garrett anyday. But it really depends if you want more later, powerband, etc.

both are a fun turbo. I vote go for more
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Old 08-07-2008, 06:55 PM   #17
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Okay so the turbo is now under question... but back to my original questions guys....

What i want to know is, what will i gain more from? Head porting or cams?

How much extra power will porting add to stock heads if nothing else is changed?

If i decide on cams will the Brian Crower BC0621 kit work in my 2ltr heads and will my AVCS still opperate correctly?

What sort of power can i expect from this setup and what other mods will net me the most gains?

Cheers guys
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Old 08-07-2008, 09:58 PM   #18
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Mark Remmick is making close to 9xx whp with stock heads. IE no porting. After talking with him, I think I am just going to go with cams for now, and maybe by a set of spare heads for later when I have the extra cash to have them worked. This way I can get a direct comparison.

Dustin
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Old 08-08-2008, 03:10 AM   #19
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With cams, you add flow by opening the valves more/longer. With porting, you add flow at the existing lift/duration. Cams will add more power than porting alone because the longer duration gives the cylinders more time to pump. They also shift the powerband much more than porting alone would.

I can't answer whether or not the BC 272 cams will fit the 207, but assuming they do and based on dyno graphs I've seen, they should shift the powerband to the right 500-800 rpm and add 40hp or so.
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Old 08-08-2008, 05:05 AM   #20
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Quote:
Originally Posted by bluescoobywagon View Post
With cams, you add flow by opening the valves more/longer. With porting, you add flow at the existing lift/duration. Cams will add more power than porting alone because the longer duration gives the cylinders more time to pump. They also shift the powerband much more than porting alone would.

I can't answer whether or not the BC 272 cams will fit the 207, but assuming they do and based on dyno graphs I've seen, they should shift the powerband to the right 500-800 rpm and add 40hp or so.
Thanks man, great response

So if the cams may add 40hp, any idea what porting might add on a stock motor for example?
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Old 08-08-2008, 08:28 AM   #21
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I would say cams over porting, cosworth and kelford does cams for the jdm avcs. Call kelford, very knowledgeable person! Ever thought of using the red instead of the green, that should give you what you are looking for and more.
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Old 08-08-2008, 08:58 AM   #22
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Quote:
Originally Posted by frayz View Post
Thanks man, great response

So if the cams may add 40hp, any idea what porting might add on a stock motor for example?
This is tough to answer. It'll depend on the level of porting and the motor combo. It'll also depend on the turbo and boost levels as larger turbos will respond to cams and porting much more than smaller turbos will. Cams that give 40 hp on a GT30R may give 70hp on a GT40R.

Since yours is a hybrid build, you would be porting in an effort to get the 2.0 heads to flow enough air for the 2.5 motor. The cams are the main limiting factor there as you end up with a 2.5 STI motor with smaller than stock cams. Extensive port work on a flow bench could get you close to 40 hp. If you threw in larger valves you could probably exceed that. If I had to choose one or the other based on budget and time, I'd go with the cams. The fact that I can do my own port work means that I went with both plus .5mm oversized valves in my build.
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Old 08-09-2008, 04:55 AM   #23
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Any other input on wether the Brian Crower 2.5 ltr AVCS cams will work in my 2ltr AVCS heads?
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Old 08-09-2008, 07:21 AM   #24
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Any other input on wether the Brian Crower 2.5 ltr AVCS cams will work in my 2ltr AVCS heads?
The cam sensor pickups are in a different location. Why don't u call them and maybe speak to Brian himself.
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Old 08-09-2008, 09:09 AM   #25
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The cam sensor pickups are in a different location. Why don't u call them and maybe speak to Brian himself.
Would this fix that?

http://www.horsepowerfreaks.com/part...e_Sensor/12196
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