stroker kit or new engine?
11 May 2003, 11:26 AM
#1
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500-600 is experimental/unproven no other way of putting it.
The STi 8 (all) and the STi 7 RA Spec C cams are rather better according to measurements on NASIOC, but for 500-600 BHP I would have thought you would be changing them to something quite fancy anyway?
[Edited by john banks - 11/5/2003 11:27:01 AM]
The STi 8 (all) and the STi 7 RA Spec C cams are rather better according to measurements on NASIOC, but for 500-600 BHP I would have thought you would be changing them to something quite fancy anyway?
[Edited by john banks - 11/5/2003 11:27:01 AM]
05 November 2003, 09:54 AM
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Hi, I need some help and recommendations before starting the project.
The car is an STi7 and the owner wants to have 500-600 bhp.
I think that it will be much easier with larger capacity and therefore I have to choose which way to choose - stroker kit or a new engine based on 2.5 legacy block with uprated everything
. It has to be a tested solution so USDM 2.5 STi shortblock is not an option.
We have here a reliable engine builder with lots of boxer engine experience and we have a budget. We also know that box and diffs will have to be changed/upgraded.
All comments and suggestions are more than welcome.
The car is an STi7 and the owner wants to have 500-600 bhp.
I think that it will be much easier with larger capacity and therefore I have to choose which way to choose - stroker kit or a new engine based on 2.5 legacy block with uprated everything
. It has to be a tested solution so USDM 2.5 STi shortblock is not an option.We have here a reliable engine builder with lots of boxer engine experience and we have a budget. We also know that box and diffs will have to be changed/upgraded.
All comments and suggestions are more than welcome.
05 November 2003, 10:58 AM
#3
Best bet in my opinion.
EJ22t closed deck block, relinered.
Head studs.
JE Forged pistons EJ25
Forged/Billet rods of your choice, Lateral Performance are proven.
Billet steel crank, 79mm stroke
Sti7 AVCS heads
Garrett GT series turbo, Lateral performance can spec and supply
Paul
EJ22t closed deck block, relinered.
Head studs.
JE Forged pistons EJ25
Forged/Billet rods of your choice, Lateral Performance are proven.
Billet steel crank, 79mm stroke
Sti7 AVCS heads
Garrett GT series turbo, Lateral performance can spec and supply
Paul
05 November 2003, 12:09 PM
#4
Reprofiled cams with properly ported sti heads. You will also need replacement valve springs, retainers and spring seats. You will also need new valve followers as the Sti heads now use integral shims. Or you could add shims to make up for the cam grind.
Paul
Paul
05 November 2003, 01:23 PM
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Pavlo:
Why is EJ22t better than EJ25? I think Christian's engine is EJ25? What is bore/stroke for original EJ22 vs EJ25?
STi7 heads with AVCS - is there any good option without variable timing? I thought we would have to change heads and cams.
As for the turbo and IC I was thinking about APS.
John:
Good point, it is experimental
Why is EJ22t better than EJ25? I think Christian's engine is EJ25? What is bore/stroke for original EJ22 vs EJ25?
STi7 heads with AVCS - is there any good option without variable timing? I thought we would have to change heads and cams.
As for the turbo and IC I was thinking about APS.
John:
Good point, it is experimental
05 November 2003, 02:03 PM
#7
You could try the semi closed deck ej25, but a standard, open deck ej25 isn't worth considering in my opinion. The welded EJ25 block is an option, I have odne it myself, but if you have the money to spend, and want the best reliability, the EJ22 relinered to the same bore as an EJ25 (99.5 std) is the way to go.
Nobody has to my knowledge really tested the semi closed deck block of the 2.5 STi with new pistons and rods.
The other consideration, is whether you want power that's useable, with a good turbo, and lots of torque, or if you just want the peak figure. Plenty of people in the US are getting high peak figures are stupidly high RPM with massive laggy turbos, which arguably puts much lower loads on the block and piston crowns.
Availability is another consideration, EJ22t blocks are very rare outside the US/Canada, and while you can get them imported, the carraige costs are high.
Axis Power Racing in the US do a good kit at around 2.4 capacity with a sleeved open deck block, but i haven't seen any results of tests that compare with what I want to do with an engine like that.
Paul
Nobody has to my knowledge really tested the semi closed deck block of the 2.5 STi with new pistons and rods.
The other consideration, is whether you want power that's useable, with a good turbo, and lots of torque, or if you just want the peak figure. Plenty of people in the US are getting high peak figures are stupidly high RPM with massive laggy turbos, which arguably puts much lower loads on the block and piston crowns.
Availability is another consideration, EJ22t blocks are very rare outside the US/Canada, and while you can get them imported, the carraige costs are high.
Axis Power Racing in the US do a good kit at around 2.4 capacity with a sleeved open deck block, but i haven't seen any results of tests that compare with what I want to do with an engine like that.
Paul
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05 November 2003, 02:18 PM
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Paul,
"The welded EJ25 block is an option, I have odne it myself, but if you have the money to spend, and want the best reliability, the EJ22 relinered to the same bore as an EJ25 (99.5 std) is the way to go."
Out of interest, I do know of a failure in an aftermarket welded "close decked" ej25 block, but as yet I don't know of any running 2.5l relinered EJ22T blocks. Do you know of any EJ22T Relinered to 2.5L builds that are in use now, or was your statement about their reliability based on theory rather than practice?
It would be great to hear of some relinered ej22t's proving reliable in everyday use, and if you know of any that would be good news.
Moray
"The welded EJ25 block is an option, I have odne it myself, but if you have the money to spend, and want the best reliability, the EJ22 relinered to the same bore as an EJ25 (99.5 std) is the way to go."
Out of interest, I do know of a failure in an aftermarket welded "close decked" ej25 block, but as yet I don't know of any running 2.5l relinered EJ22T blocks. Do you know of any EJ22T Relinered to 2.5L builds that are in use now, or was your statement about their reliability based on theory rather than practice?
It would be great to hear of some relinered ej22t's proving reliable in everyday use, and if you know of any that would be good news.
Moray
05 November 2003, 03:59 PM
#9
Moray,
I beleive that a number of larger motors in Australia are based on EJ22t blocks. But as you correctly point out, welded blocks have been known to fail. That said, PMS claim their welding of blocks has greatly improved their reliablity.
The cracked (welded) block you speak of, I was curious to know if that block started as a brand new block just prior to welding. As the blocks that I have aquired, have been badly distorted, perhaps as a result of overheating, or maybe it caused it (head gasket failure).
If a new and unseasoned block were used for the basis of a closed deck block, I can see it distorting in the same way as a standard one.
Looks like we will get a better idea when I run my engine in, which seems like a much better way of selling it!
Paul
I beleive that a number of larger motors in Australia are based on EJ22t blocks. But as you correctly point out, welded blocks have been known to fail. That said, PMS claim their welding of blocks has greatly improved their reliablity.
The cracked (welded) block you speak of, I was curious to know if that block started as a brand new block just prior to welding. As the blocks that I have aquired, have been badly distorted, perhaps as a result of overheating, or maybe it caused it (head gasket failure).
If a new and unseasoned block were used for the basis of a closed deck block, I can see it distorting in the same way as a standard one.
Looks like we will get a better idea when I run my engine in, which seems like a much better way of selling it!
Paul
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