Apparently it's true...
08-20-2003 | 04:01 PM
#32
1. Ok, the USDM STi motor is detting why? B/c of combustion chamber design, or b/c of tuning??
And I agree to a point about using a thicker head gasket as a "cheap" alternative, ... but it's not always necessary to change the design of piston tops or 'whatever'. I just think it is a good alternative.
2. Subaru's aren't Ford's.
3. Chris is using the xede, ... many things can be monitored and adjusted to compensate. I'm not saying that's the best way to do things, but it will work, and I believe it will work well for the money spent. If he could afford different pistons and installation now, that'd be great. But i-speed isn't even releasing the specs on the pistons yet.
So it may as well be a shot in the dark right now as to which to use.
Is bolting the stock wrx heads up to an STi block an ideal solution for more power? I'd say No. Are there going to be noticeable, safe gains? I'd say most definitely Yes, with proper tuning.
If I were able to do what Chris is doing, I'd probably be doing it the same way. If I could afford different pistons, I'd try to doit while the block was out, if I couldn't I'd just do it later on. I'd also do asa Richard mentioned about getting static compression checked, and of course valve clearance. Would I worry about cam timing changes from running a thicker head gasket? No.
again, ... just my 0.000000000002¢
Sean
(and you guys spend too much time on the computer!!
I can't get on here long enough, or often enough to keep up! )
And I agree to a point about using a thicker head gasket as a "cheap" alternative, ... but it's not always necessary to change the design of piston tops or 'whatever'. I just think it is a good alternative.
2. Subaru's aren't Ford's.
3. Chris is using the xede, ... many things can be monitored and adjusted to compensate. I'm not saying that's the best way to do things, but it will work, and I believe it will work well for the money spent. If he could afford different pistons and installation now, that'd be great. But i-speed isn't even releasing the specs on the pistons yet.
So it may as well be a shot in the dark right now as to which to use. Is bolting the stock wrx heads up to an STi block an ideal solution for more power? I'd say No. Are there going to be noticeable, safe gains? I'd say most definitely Yes, with proper tuning.
If I were able to do what Chris is doing, I'd probably be doing it the same way. If I could afford different pistons, I'd try to doit while the block was out, if I couldn't I'd just do it later on. I'd also do asa Richard mentioned about getting static compression checked, and of course valve clearance. Would I worry about cam timing changes from running a thicker head gasket? No.
again, ... just my 0.000000000002¢
Sean
(and you guys spend too much time on the computer!!
I can't get on here long enough, or often enough to keep up! )
08-20-2003 | 04:35 PM
#33
Registered User
iTrader: (14)
Joined: Jan 2003
Posts: 1,224
From: Honolulu, HI
Car Info: 1991 Toyota MR-2 Turbo
Originally posted by Stroker
What amount is significant?
One reply you are being anial, and the next, cam timing is not significant.
At least be consistant with your opinions.
What amount is significant?
One reply you are being anial, and the next, cam timing is not significant.
At least be consistant with your opinions.
08-20-2003 | 05:04 PM
#34
Originally posted by Nolimit
1. Ok, the USDM STi motor is detting why? B/c of combustion chamber design, or b/c of tuning??
And I agree to a point about using a thicker head gasket as a "cheap" alternative, ... but it's not always necessary to change the design of piston tops or 'whatever'. I just think it is a good alternative.
2. Subaru's aren't Ford's.
3. Chris is using the xede, ... many things can be monitored and adjusted to compensate. I'm not saying that's the best way to do things, but it will work, and I believe it will work well for the money spent. If he could afford different pistons and installation now, that'd be great. But i-speed isn't even releasing the specs on the pistons yet. So it may as well be a shot in the dark right now as to which to use.
Is bolting the stock wrx heads up to an STi block an ideal solution for more power? I'd say No. Are there going to be noticeable, safe gains? I'd say most definitely Yes, with proper tuning.
If I were able to do what Chris is doing, I'd probably be doing it the same way. If I could afford different pistons, I'd try to doit while the block was out, if I couldn't I'd just do it later on. I'd also do asa Richard mentioned about getting static compression checked, and of course valve clearance. Would I worry about cam timing changes from running a thicker head gasket? No.
again, ... just my 0.000000000002¢
Sean
(and you guys spend too much time on the computer!! I can't get on here long enough, or often enough to keep up! )
1. Ok, the USDM STi motor is detting why? B/c of combustion chamber design, or b/c of tuning??
And I agree to a point about using a thicker head gasket as a "cheap" alternative, ... but it's not always necessary to change the design of piston tops or 'whatever'. I just think it is a good alternative.
2. Subaru's aren't Ford's.
3. Chris is using the xede, ... many things can be monitored and adjusted to compensate. I'm not saying that's the best way to do things, but it will work, and I believe it will work well for the money spent. If he could afford different pistons and installation now, that'd be great. But i-speed isn't even releasing the specs on the pistons yet.
So it may as well be a shot in the dark right now as to which to use. Is bolting the stock wrx heads up to an STi block an ideal solution for more power? I'd say No. Are there going to be noticeable, safe gains? I'd say most definitely Yes, with proper tuning.
If I were able to do what Chris is doing, I'd probably be doing it the same way. If I could afford different pistons, I'd try to doit while the block was out, if I couldn't I'd just do it later on. I'd also do asa Richard mentioned about getting static compression checked, and of course valve clearance. Would I worry about cam timing changes from running a thicker head gasket? No.
again, ... just my 0.000000000002¢
Sean
(and you guys spend too much time on the computer!!
I can't get on here long enough, or often enough to keep up! )
I'm looking at completion by next summer.
Until then, wanna PM me with a list of what I need to do this?
08-20-2003 | 05:28 PM
#35
Originally posted by Chibby Goku
Thanks Sean! I guess I'll extend my project and build this thing right.
I'm looking at completion by next summer. Until then, wanna PM me with a list of what I need to do this?
Thanks Sean! I guess I'll extend my project and build this thing right.
I'm looking at completion by next summer.
Until then, wanna PM me with a list of what I need to do this?
Are you gonna wait? Or just bolt it in now, and maybe change things later on if needed? One of the things I wonder about is that, has anyone even tried it like you're doing yet? I mean, if it's proven to have problems, then that's one thing, but if not, ..... well, I would try it, but I'm kinda experimental about stuff like that.
So I would say go for it, ... just know that things may not go smoothly. 
anyhow, I will know by next week if I got a 'new job' or not, .... if I do get it, .... my poor car won't be so ..... 'poor' anymore.
08-20-2003 | 05:37 PM
#36
Thread Starter
Pr0n King
iTrader: (3)
Joined: Nov 2002
Posts: 26,618
From: The Land of Rocks
Car Info: Turncoat Turbo
I now agree with everybody.
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08-20-2003 | 05:52 PM
#37
Thread Starter
Pr0n King
iTrader: (3)
Joined: Nov 2002
Posts: 26,618
From: The Land of Rocks
Car Info: Turncoat Turbo
The swapping of pistons is done to keep the compression lower than stock STi which in turn makes for safe and reliable power when using the USDM WRX heads.
We think it's safe to say that you can still use the wrx heads with the stock STI SB. However, the added increase in compression (over 10% from what they were designed for) will result in unhappy motoring (performance wise and of course head gasket wise).
Chris
I-Speed USA
cescamilla@i-speedusa.com
We think it's safe to say that you can still use the wrx heads with the stock STI SB. However, the added increase in compression (over 10% from what they were designed for) will result in unhappy motoring (performance wise and of course head gasket wise).
Chris
I-Speed USA
cescamilla@i-speedusa.com
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08-20-2003 | 05:58 PM
#39
Thread Starter
Pr0n King
iTrader: (3)
Joined: Nov 2002
Posts: 26,618
From: The Land of Rocks
Car Info: Turncoat Turbo
12:1 is excessive to me. i wanted 10:1 with my set up but i decided to go with 9:1. 10% is nothing. good tuning, good gas, and a good set up makes good power. nothing wrong with 10:1 or less.
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08-20-2003 | 06:01 PM
#40
Thread Starter
Pr0n King
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Joined: Nov 2002
Posts: 26,618
From: The Land of Rocks
Car Info: Turncoat Turbo
Looks like if the formula that Jeff posted is right (which I don't doubt) the STi block with WRX heads will be ~9.0:1 compression. Not that bad at all.
The USDM WRX's EJ20 as we all know is 7.8:1. That's a little more than 1 full point of increase.
Seems like something that can be tuned around.
If it were up to me, I'd run a lower compression and higher boost - but we play the hand we've been dealt, right?
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The USDM WRX's EJ20 as we all know is 7.8:1. That's a little more than 1 full point of increase.
Seems like something that can be tuned around.
If it were up to me, I'd run a lower compression and higher boost - but we play the hand we've been dealt, right?
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Last edited by IS2Scooby; 08-20-2003 at 06:03 PM.
08-20-2003 | 06:50 PM
#41
Registered User
iTrader: (2)
Joined: Nov 2002
Posts: 1,145
From: AWD Culture
Car Info: White on Gold STi
I see nothing wrong with 9.0-1 compression. If I were to build a motor that's what compperssion I would run..... help give a little better bottom end and for track days get some race gas with a good tune great power potential. Besides thats what my motor runs stock
08-21-2003 | 01:18 AM
#42
VIP Member
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Posts: 10,133
From: Lastweek Lane - Watertown, NY
Car Info: 02WRXpseudoSTiWannabeWagon
Originally posted by Nolimit
There Also are other options, you can buy a thicker metal head gasket (like a lot of people do), that's not a big deal.
my $0.0000002
Sean
There Also are other options, you can buy a thicker metal head gasket (like a lot of people do), that's not a big deal.
my $0.0000002
Sean
PWR enterprises head gasket
All $199
Apexi Head Gasket 2.1mm/93.5mm bore
Apexi Head Gasket 1.5mm/93.5mm bore
Apexi Head Gasket .8mm/93.5mm bore
08-21-2003 | 08:33 AM
#43
It looks like they figured 8.66:1 CR, stock USDM WRX is 8.2:1. Unless there is valve interference, I would go for it. The increase in compression seems negligible... However, I would include new cams on my christmas list. Hey, I have a question. Let's say the WRX heads works on the STi block. Could aftermarket cams induce valve interference?
08-21-2003 | 02:42 PM
#44
Originally posted by IS2Scooby
I now agree with everybody.
I now agree with everybody.
lol 
For real though, I'd go for it, either way you look at it, there will be gains, tq tq tq tq, .... that's what I'd want it fr originally anyhoo. And the higher compression can help spool up that bigger turbo!!