Bugeye WRX 2.5 conversion ......which heads ?
24 July 2010, 11:11 PM
#1
Bugeye WRX 2.5 conversion ......which heads ?
Help needed as usual 
looking at a 2.5 conversion short block into my Bugeye...... Hopefully the mods already in place can cope but wondering about the "black art" of heads ??
Can I just use my Bugeye WRX heads or do I need something different ??
There are some heads on here which seem to have been ported for the 2.5 ..
https://www.scoobynet.com/private-fo...for-2-5-a.html
Cheers
Shaun
looking at a 2.5 conversion short block into my Bugeye...... Hopefully the mods already in place can cope but wondering about the "black art" of heads ??
Can I just use my Bugeye WRX heads or do I need something different ??
There are some heads on here which seem to have been ported for the 2.5 ..
https://www.scoobynet.com/private-fo...for-2-5-a.html
Cheers
Shaun
25 July 2010, 12:18 AM
#2
Help needed as usual
looking at a 2.5 conversion short block into my Bugeye...... Hopefully the mods already in place can cope but wondering about the "black art" of heads ??
Can I just use my Bugeye WRX heads or do I need something different ??
There are some heads on here which seem to have been ported for the 2.5 ..
https://www.scoobynet.com/private-fo...for-2-5-a.html
Cheers
Shaun
looking at a 2.5 conversion short block into my Bugeye...... Hopefully the mods already in place can cope but wondering about the "black art" of heads ??
Can I just use my Bugeye WRX heads or do I need something different ??
There are some heads on here which seem to have been ported for the 2.5 ..
https://www.scoobynet.com/private-fo...for-2-5-a.html
Cheers
Shaun
Ryan
25 July 2010, 01:04 AM
#3
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The V2 heads are not compatable with the newage due to a different bolt pattern for the inlet manifold afaik.
They will be good heads if Steve Whitson did the work!
They will be good heads if Steve Whitson did the work!
25 July 2010, 10:14 AM
#4
Exactly! I've been trying to sell these heads for ages without any luck at all. Was advised to advertise them at double what I'm asking for them by the man himself. Then halfed the price and still no takers. The work on these or any others being made to the same spec would be £500 for labour alone!
Ryan
Ryan
25 July 2010, 11:00 PM
#5
Hmm......just wondering what might happen if my MY 02 Bugeye WRX heads are bolted to a STi 2.5 block !!
I assume the CR will increase amomng other things ?
Where's Paul Blamire, Alan Jeffrey, David (API).........and the rest when you need them LOL
Shaun
I assume the CR will increase amomng other things ?
Where's Paul Blamire, Alan Jeffrey, David (API).........and the rest when you need them LOL
Shaun
25 July 2010, 11:22 PM
#6
Shaun,
The CR will also be dependent on what pistons you choose (dish volume) and how much is skimmed from the blocks.
A decent block builder will work out the TDC volume for the block, then there is the head and HG volumes to feed into the CR calculation.
There is a bit of help here with various volumes:
http://forums.nasioc.com/forums/show....php?t=1667168
Nick
The CR will also be dependent on what pistons you choose (dish volume) and how much is skimmed from the blocks.
A decent block builder will work out the TDC volume for the block, then there is the head and HG volumes to feed into the CR calculation.
There is a bit of help here with various volumes:
http://forums.nasioc.com/forums/show....php?t=1667168
Nick
25 July 2010, 11:32 PM
#7
I'm going for the ej257, with my 2002 wrx heads bolted on top. You need the chamber cc's adjusted to match the 2.5 and porting to aid flow. I'm guessing the 2 litre heads would go straight on, but would be a waste of time without above work done to them? I'm sure the wrx heads have tumblers that need removed to improve power also. Somone else should be a bit more accurate with information on this than me.
Ryan
Ryan
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25 July 2010, 11:33 PM
#8
I'm going for the ej257, with my 2002 wrx heads bolted on top. You need the chamber cc's adjusted to match the 2.5 and porting to aid flow. I'm guessing the 2 litre heads would go straight on, but would be a waste of time without above work done to them? I'm sure the wrx heads have tumblers that need removed to improve power also. Somone else should be a bit more accurate with information on this than me.
Ryan
Ryan
25 July 2010, 11:45 PM
#9
Could you not use the modified V2 STi heads with the matching inlet manifold ?
The newage manifold won't fit onto the earlier heads or vice versa because of the bolt pattern but any 2.0 heads bolt onto the 2.5 block.
What would stop you using an inlet manifold that matches (ie. V1-V4) and then dropping in the complete engine assembly ?
If all the bits from your newage manifold will fit onto the 'classic' manifold, you could buy these STi heads at a bargain price, all you need is a cheap manifold off ebay !
You do need to confirm with someone far more knowlegable than myself that your bits will fit the 'old style' manifold first however !
The newage manifold won't fit onto the earlier heads or vice versa because of the bolt pattern but any 2.0 heads bolt onto the 2.5 block.
What would stop you using an inlet manifold that matches (ie. V1-V4) and then dropping in the complete engine assembly ?
If all the bits from your newage manifold will fit onto the 'classic' manifold, you could buy these STi heads at a bargain price, all you need is a cheap manifold off ebay !
You do need to confirm with someone far more knowlegable than myself that your bits will fit the 'old style' manifold first however !
29 July 2010, 08:00 PM
#12
Mike
If I buy 2.0 heads I'd stil have to have them altered as the cubic capacity of the bowl is all wrong and they would also be the wrong diameter.... I'm aiming for something simple
My car is about 400 at the moment, I Just wanted to "future proof" for the next few years as I'm going to keep the car until it falls apart LOL
Still enjoying wakey ??
Cheers
Shaun
If I buy 2.0 heads I'd stil have to have them altered as the cubic capacity of the bowl is all wrong and they would also be the wrong diameter.... I'm aiming for something simple
My car is about 400 at the moment, I Just wanted to "future proof" for the next few years as I'm going to keep the car until it falls apart LOL
Still enjoying wakey ??
Cheers
Shaun
29 July 2010, 08:19 PM
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Ahhhh I see, I'm thinking about big power 2.0-2.1s etc
Yeah I'm still enjoying living down here, just started a new job last month, I'm now a Caravan sales executive( posh title ). Have you settled into your new home? How's your family?
Yeah I'm still enjoying living down here, just started a new job last month, I'm now a Caravan sales executive( posh title
). Have you settled into your new home? How's your family?
Hows it going Mike?
29 July 2010, 09:07 PM
#15
I think you will find that wether or not work should be done on 2ltr heads to make them fit better the 2.5 block is pretty much a split camp amongst the very few that appear to have a view upon the matter.
I asked the question of David Knights local to me here in Northampton who do purely head work and he pretty much said how on earth can I manage to do that properly.
API did my 2.5/WRX heads conversion and the subject of increasing the cc of the bowl was never discussed.
The 2.5/2ltr head is reliable and to do re-sizing I'm sure brings in risk and uncertainty.
The right turbo, at least equivalent MD321T or V, air flow into the engine and the ability to run safe higher boost are what I'd be looking for.
Trev
I asked the question of David Knights local to me here in Northampton who do purely head work and he pretty much said how on earth can I manage to do that properly.
API did my 2.5/WRX heads conversion and the subject of increasing the cc of the bowl was never discussed.
The 2.5/2ltr head is reliable and to do re-sizing I'm sure brings in risk and uncertainty.
The right turbo, at least equivalent MD321T or V, air flow into the engine and the ability to run safe higher boost are what I'd be looking for.
Trev
how's things out west?
30 July 2010, 10:01 AM
#17
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Hmmmm several comments come to mind here.
The original heads will work but are small port with nothing special for cams. They cannot flow enough air in standard form to cope with big turbo.
The better heads - without going down the Avecs route, would be STi 5 or 6, they bolt straight on and work well. I think as a comparison, we gained some 40 hp on a car that originally made 419 on the WRX heads with nothing else changed. You would need STi 5 cam wheels to match the heads as the trigger points on the Avecs pulleys are in the wrong place.
Avecs cams are designed to do their job as Avecs and no matter how you statically time them, the result will be compromised.
Wiring in the Avecs is time consuming and not for the faint hearted.
Fitting Version 4 backwards manifolds and heads to a Vers 5 on type engine is also a fraught-with-pitfalls job, as all of the senders and electronics are wired differently with differing connectors. It can be done - but is best avoided.
David APi
The original heads will work but are small port with nothing special for cams. They cannot flow enough air in standard form to cope with big turbo.
The better heads - without going down the Avecs route, would be STi 5 or 6, they bolt straight on and work well. I think as a comparison, we gained some 40 hp on a car that originally made 419 on the WRX heads with nothing else changed. You would need STi 5 cam wheels to match the heads as the trigger points on the Avecs pulleys are in the wrong place.
Avecs cams are designed to do their job as Avecs and no matter how you statically time them, the result will be compromised.
Wiring in the Avecs is time consuming and not for the faint hearted.
Fitting Version 4 backwards manifolds and heads to a Vers 5 on type engine is also a fraught-with-pitfalls job, as all of the senders and electronics are wired differently with differing connectors. It can be done - but is best avoided.
David APi
30 July 2010, 10:46 AM
#18
I understood that AVCS cams have the same duration as WRX cams but with more lift, so I don't understand what compromise there is if not activated by the trick cam wheels?
Installing STi AVCS heads but with the solenoids not connected, the oil ports on EX cams sealed up and reusing the WRX cam wheels and position pick up sees to be a proven method in the US.
Some even put AVCS cams into WRX heads, again with the oil ports sealed up.
Installing STi AVCS heads but with the solenoids not connected, the oil ports on EX cams sealed up and reusing the WRX cam wheels and position pick up sees to be a proven method in the US.
Some even put AVCS cams into WRX heads, again with the oil ports sealed up.
30 July 2010, 11:08 AM
#19
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I understood that AVCS cams have the same duration as WRX cams but with more lift, so I don't understand what compromise there is if not activated by the trick cam wheels?
Installing STi AVCS heads but with the solenoids not connected, the oil ports on EX cams sealed up and reusing the WRX cam wheels and position pick up sees to be a proven method in the US.
Some even put AVCS cams into WRX heads, again with the oil ports sealed up.
Installing STi AVCS heads but with the solenoids not connected, the oil ports on EX cams sealed up and reusing the WRX cam wheels and position pick up sees to be a proven method in the US.
Some even put AVCS cams into WRX heads, again with the oil ports sealed up.
We had found something that did work without any fuss.
David
PS I don't take any notice or heed of what the yanks do. In my experience the result is often a compromise, which after all the work they have done to make it happen is not good enough in a professional advice perspective.
I adopted that stance after a situation many years ago when one of them came on here about rewiring a car to make a US wrx into a JDM Sti or something similar. And it went to several pages about stripping out the original wiring loom and separating all [ ALL ] the wires and identifying this and identifyting that and join reds to green whites etc., etc., _ you get the drift ??
Last edited by APIDavid; 30 July 2010 at 11:23 AM.
30 July 2010, 11:08 AM
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30 July 2010, 12:02 PM
#21
David...... I'm not after big power
If I can't find any STi ver 5/6 heads can I just bolt on my Bugeye WRX heads and at least get the car up and running ?
Cheers
Shaun
PS would these heads bolt on and be OK with a newage manifold ?
https://www.scoobynet.com/private-fo...-complete.html
If I can't find any STi ver 5/6 heads can I just bolt on my Bugeye WRX heads and at least get the car up and running ?
Cheers
Shaun
PS would these heads bolt on and be OK with a newage manifold ?
https://www.scoobynet.com/private-fo...-complete.html
Last edited by Midlife......; 30 July 2010 at 12:05 PM.
30 July 2010, 12:40 PM
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David...... I'm not after big power
If I can't find any STi ver 5/6 heads can I just bolt on my Bugeye WRX heads and at least get the car up and running ?
Cheers
Shaun
PS would these heads bolt on and be OK with a newage manifold ?
https://www.scoobynet.com/private-fo...-complete.html
If I can't find any STi ver 5/6 heads can I just bolt on my Bugeye WRX heads and at least get the car up and running ?
Cheers
Shaun
PS would these heads bolt on and be OK with a newage manifold ?
https://www.scoobynet.com/private-fo...-complete.html
David
PS yes you can go with what you've got now, but they don't flow much air due to the small porting and it will be disappointing.
30 July 2010, 02:05 PM
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David
30 July 2010, 07:02 PM
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You can run the 2.0 hears as long as you run the thicker head gasket, the CR will still be higher than the factory 2.5 style heads, but will be manageable for a good tuner. You other option is to have the combustion chambers ont eh heads opened up to correct the CR and get the heads to match the larger cylinder bore. If you are goign that far some port work will be easy to do at the same time. as for cams the STI cams from a US 2.5 STI are a botl in to the 2.0 heads if you block the AVCS oil passages on them.
We just did a 2.5 block on my wife's car (was a 2 liter) she ported the heads, match the combustion chamber, and installed some 06 up 2.5STI cams (they are hollow so les mass in the valve train)
We just did a 2.5 block on my wife's car (was a 2 liter) she ported the heads, match the combustion chamber, and installed some 06 up 2.5STI cams (they are hollow so les mass in the valve train)
30 July 2010, 07:03 PM
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You can run the 2.0 hears as long as you run the thicker head gasket, the CR will still be higher than the factory 2.5 style heads, but will be manageable for a good tuner. You other option is to have the combustion chambers ont eh heads opened up to correct the CR and get the heads to match the larger cylinder bore. If you are goign that far some port work will be easy to do at the same time. as for cams the STI cams from a US 2.5 STI are a botl in to the 2.0 heads if you block the AVCS oil passages on them.
We just did a 2.5 block on my wife's car (was a 2 liter) she ported the heads, match the combustion chamber, and installed some 06 up 2.5STI cams (they are hollow so les mass in the valve train)
We just did a 2.5 block on my wife's car (was a 2 liter) she ported the heads, match the combustion chamber, and installed some 06 up 2.5STI cams (they are hollow so les mass in the valve train)