engine problem on a p1
Discussion
My engine went recently and i have a 2.5 bottom end lined up. It isn't done yet but i am going to put my car away pretty soon and start stripping the engine out and down. It will save me time when i come to do the rebuild. Just waiting to get the dosh together for this engine and other bits. Once i have it i can do the honours.
The 2.5 is a semi-closed deck block which is good and i remember Vixpy1 saying they should be good for 450bhp no probs with standard internals. He knows of a chap running 500bhp on a 2.5STi with standard internals so they must be pretty strong.
I can't remember if the 2.0L P1 block is closed or semi-closed. I think 22b's are a closed deck, and the spec C is a closed deck which makes them much stronger than a semi-closed deck. However....all that said it may be that you stick with the P1 block if it's OK and just need a new crank. I think the 2.5 conversion is a good way forward though with excellent potential for decent power later on.
A 2.5 bottom end with your P1 heads and other bits should be pretty interesting too i imagine. I am only using the bits off my WRX as a make do until i can get better heads and other such bits but your P1 stuff has got to be much better than my WRX bits.
I think we need some expert advice here. Calling Vixpy1, JohnF or anyone else that knows the craic on these conversions!!
The 2.5 is a semi-closed deck block which is good and i remember Vixpy1 saying they should be good for 450bhp no probs with standard internals. He knows of a chap running 500bhp on a 2.5STi with standard internals so they must be pretty strong.
I can't remember if the 2.0L P1 block is closed or semi-closed. I think 22b's are a closed deck, and the spec C is a closed deck which makes them much stronger than a semi-closed deck. However....all that said it may be that you stick with the P1 block if it's OK and just need a new crank. I think the 2.5 conversion is a good way forward though with excellent potential for decent power later on.
A 2.5 bottom end with your P1 heads and other bits should be pretty interesting too i imagine. I am only using the bits off my WRX as a make do until i can get better heads and other such bits but your P1 stuff has got to be much better than my WRX bits.
I think we need some expert advice here. Calling Vixpy1, JohnF or anyone else that knows the craic on these conversions!!
ScoobieWRX said:
I can't remember if the 2.0L P1 block is closed or semi-closed. I think 22b's are a closed deck, and the spec C is a closed deck which makes them much stronger than a semi-closed deck.
The STi-RA was closed deck up until version 2, from v3 on it was open or semi-closed, not sure which (or what the difference is). IIRC the P1 was based on the v5 STi-R so probably won't be a close deck.ScoobieWRX said:
The 2.5 is a semi-closed deck block which is good and i remember Vixpy1 saying they should be good for 450bhp no probs with standard internals. He knows of a chap running 500bhp on a 2.5STi with standard internals so they must be pretty strong.
Thats on 2.0 Sti 8 engine chap, 2.5 sti is not as strong.
Vixpy1 said:
ScoobieWRX said:
The 2.5 is a semi-closed deck block which is good and i remember Vixpy1 saying they should be good for 450bhp no probs with standard internals. He knows of a chap running 500bhp on a 2.5STi with standard internals so they must be pretty strong.
Thats on 2.0 Sti 8 engine chap, 2.5 sti is not as strong.Just to cure my confusion please
Edited by ScoobieWRX on Friday 22 February 00:03
P1 is just an STi5 engine, which uses an open deck block. Spec C is a semi-closed deck block. 22B is a closed deck EJ22, but not the same spec block as an EJ22T with piston oil squirters, which is the best block for high power builds, some of the early 2.0 phase 1 blocks were closed deck with piston oil squirters.
If you intend to go the 2.5 route, you need to budget for a remap and ideally a turbo swap, as the turbo wont be large enough to flow enough air to take advantage of the extra 500cc. You also need to be aware that the rev limit will drop, so your tacho red line wont be correct. The 2.5 bottom end is a good swap in terms of the base short motor costs, but to do it properly you are looking at modifying the heads to match the larger bore, and extra costs on top.
I personally wouldnt bother with a 2.5 (i didnt), a better route would be to use the STi9 nitrided and crossdrilled crank, it comes like that straight out of the factory, you then dont need to worry about remaps and turbo swaps or insurance issues with a 2.5. If the rods are damaged a set of STi9 rods are cheap and strong enough for mid 400's, there are a some of these about 2nd hand with very few miles on them, STi8 pistons are a nice swap into the STi5/P1 engine but need a remap as they raise the compresion slightly, the stock STi5/P1 pistons are good forged items too so if budget is tight stick with them.
First thing is to find out whats wrong of course, but if its a typical failure you will need a new crank and posibly rods, depending on mileage it may require oversize pistons, but often a hone and your current pistons with new rings will be fine, get the bores checked profesionally.
Once rebuilt replace the MAF sensor as a first job before you even run it in, and if you are using an aftermarket air filter, throw it in the bin and use an STi Group N dry air filter or normal P1 air filter in the stock housing. Get the fuel pump flow rate checked or replace it with a Walbro uprated item.
If you intend to go the 2.5 route, you need to budget for a remap and ideally a turbo swap, as the turbo wont be large enough to flow enough air to take advantage of the extra 500cc. You also need to be aware that the rev limit will drop, so your tacho red line wont be correct. The 2.5 bottom end is a good swap in terms of the base short motor costs, but to do it properly you are looking at modifying the heads to match the larger bore, and extra costs on top.
I personally wouldnt bother with a 2.5 (i didnt), a better route would be to use the STi9 nitrided and crossdrilled crank, it comes like that straight out of the factory, you then dont need to worry about remaps and turbo swaps or insurance issues with a 2.5. If the rods are damaged a set of STi9 rods are cheap and strong enough for mid 400's, there are a some of these about 2nd hand with very few miles on them, STi8 pistons are a nice swap into the STi5/P1 engine but need a remap as they raise the compresion slightly, the stock STi5/P1 pistons are good forged items too so if budget is tight stick with them.
First thing is to find out whats wrong of course, but if its a typical failure you will need a new crank and posibly rods, depending on mileage it may require oversize pistons, but often a hone and your current pistons with new rings will be fine, get the bores checked profesionally.
Once rebuilt replace the MAF sensor as a first job before you even run it in, and if you are using an aftermarket air filter, throw it in the bin and use an STi Group N dry air filter or normal P1 air filter in the stock housing. Get the fuel pump flow rate checked or replace it with a Walbro uprated item.
Can probably find more costs / options at www.p1woc.co.uk.
Friendly bunch over there!!
Bradders (former P1 owner)
Friendly bunch over there!!
Bradders (former P1 owner)
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