2.5 L conversion help!
#1
2.5 L conversion help!
Okay can someone thats done the 2.5L mods etc help with a few questions i have please...
Whats the max bhp the oe 2.5L internals can handle - taking it that injectors, intercooler etc wouldn't be a factor.
What gaskets are best to use with big power figures...and what about the head bolts - whos best for those...
What sort of prices would you expect to buy the block and have it fitted?
Would oe MY02 WRX valves be a problem due to their size?
Whats the max bhp the oe 2.5L internals can handle - taking it that injectors, intercooler etc wouldn't be a factor.
What gaskets are best to use with big power figures...and what about the head bolts - whos best for those...
What sort of prices would you expect to buy the block and have it fitted?
Would oe MY02 WRX valves be a problem due to their size?
#2
Have a read of John's & my threads, most of the answers can be found within them.
My own opinion is;
400bhp
Cometic or Standard gaskets
OEM or APR head bolts
£1100-1200 just for the short engine, fitting extra
I don't believe the valves would be a problem
Mark A
My own opinion is;
400bhp
Cometic or Standard gaskets
OEM or APR head bolts
£1100-1200 just for the short engine, fitting extra
I don't believe the valves would be a problem
Mark A
#3
Scooby Regular
Join Date: Nov 2000
Location: 32 cylinders and many cats
Posts: 18,658
Likes: 0
Received 1 Like
on
1 Post
I'm trying mine at what I think is about 480 BHP and 440 lbft (certainly feels ridiculously faster than the old dyno tested 434 BHP and 395 lbft), its OK so far, but very early days. What I am seeing is encouraging. I am being very cautious with fuelling, timing and temperatures. The 740cc injectors are at 84% at 3.5 bar pressure, 11:1 AFR.
#7
Scooby Regular
I'd go along with Mark's answers.
Over 1.4 bar and 400bhp has yet to be proven reliable
I expect your looking at £600+ for the swap depending on where you go and what else you do
Over 1.4 bar and 400bhp has yet to be proven reliable
I expect your looking at £600+ for the swap depending on where you go and what else you do
Trending Topics
#8
Scooby Regular
Join Date: Mar 2002
Location: Fcon Power Writer
Posts: 4,338
Likes: 0
Received 0 Likes
on
0 Posts
Mine lasted for 6000miles at 500/450
Gut feeling is 420/420 max for std internals but this makes for a very very fast road car...
Other things need to be taken into consideration..... not all heads are suitable for the usdm 2.5 engine... and will not take timing or reap the CC increase benefits...
£1200 engine
OEM bolts
Oem gaskets
I will prob go this route again in the future but will be kept at 420ish of each
Rob
Gut feeling is 420/420 max for std internals but this makes for a very very fast road car...
Other things need to be taken into consideration..... not all heads are suitable for the usdm 2.5 engine... and will not take timing or reap the CC increase benefits...
£1200 engine
OEM bolts
Oem gaskets
I will prob go this route again in the future but will be kept at 420ish of each
Rob
#9
What heads would those be? phase 1 and 1.5? i've got ver3 sti heads with the new version na ej25 headgaskets on mine and find it takes good timing from 4.5k on but really dosn't like it from 3.5k to 4.5k. even at low boost of 10psi.
#11
No. just a recon. if i had the engine apart again for some reson(witch i hope i don't) i would reshape the combustion chamber to look more like the phase 2 and to make them match the bore size.
#12
Scooby Regular
Join Date: Mar 2002
Location: Fcon Power Writer
Posts: 4,338
Likes: 0
Received 0 Likes
on
0 Posts
I copied Pavlo's work as best i could remember on my own heads (phase one) my car, and two cars he did the heads on all take good timing throughout...
IMHO phase two Uk cams are a waste of time, even more so 2001 onwards (Heads are ****e).
Rob
IMHO phase two Uk cams are a waste of time, even more so 2001 onwards (Heads are ****e).
Rob
Last edited by tweenierob; 09 April 2005 at 10:55 PM.
#14
Scooby Regular
Join Date: Mar 2002
Location: Fcon Power Writer
Posts: 4,338
Likes: 0
Received 0 Likes
on
0 Posts
sorry should have read uk cams are no good IMHO rather than head design..
Phase two combustion chambers arent all they are cracked up to be IMO
My phase one heads worked very well on my car.... i changed the combustion chamber shape though..
Rob
Phase two combustion chambers arent all they are cracked up to be IMO
My phase one heads worked very well on my car.... i changed the combustion chamber shape though..
Rob
#16
Scooby Regular
Join Date: Mar 2002
Location: Fcon Power Writer
Posts: 4,338
Likes: 0
Received 0 Likes
on
0 Posts
I will try and find them, they are on a disc that i wrote before i formatted (along with 20 others)
My cams were similar to ver 3 STi it seems..
Rob
My cams were similar to ver 3 STi it seems..
Rob
#17
Scooby Regular
Surely the gearbox will give up at 400/400 though??
I am talking about a Phase 1.5 MY98 UK Gearbox... Would an STi/WRX 'box be any different??
The complete cost of the conversion is more like 4k though isnt it, as I was impressed with the initial £1200 figure I read about a wee while ago..
Cheers,
Grant
I am talking about a Phase 1.5 MY98 UK Gearbox... Would an STi/WRX 'box be any different??
The complete cost of the conversion is more like 4k though isnt it, as I was impressed with the initial £1200 figure I read about a wee while ago..
Cheers,
Grant
#19
Scooby Regular
Join Date: Oct 2001
Location: aberdeenshire
Posts: 751
Likes: 0
Received 0 Likes
on
0 Posts
i am thinking about doing this convertion using 93 wrx heads what all do i need to do to these heads?
got tdo5/6 20 g
740 cc injectors
and ruuning apexi power fc
cheers david
got tdo5/6 20 g
740 cc injectors
and ruuning apexi power fc
cheers david
#21
415Bhp and 427Bhp here at 1.3 Bar with a tractive effort on the rollers of 1800 lb/ft
And the standard box didnt last long at all, infact it blew up on the road test after the final mapping
And the standard box didnt last long at all, infact it blew up on the road test after the final mapping
#22
MY my01 5 speed gear box seems to be holding up ok !
but I have gone a slightly different route with a smaller turbo hence less lag (none) & figures of about 350/350 !
but I have gone a slightly different route with a smaller turbo hence less lag (none) & figures of about 350/350 !
Last edited by Fulham71; 11 April 2005 at 07:05 AM.
#23
Scooby Regular
Join Date: Jan 2005
Location: 01274 881106 www.theRacingline.co.uk West Yorkshire
Posts: 231
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by DaveBlueRA
415Bhp and 427Bhp here at 1.3 Bar with a tractive effort on the rollers of 1800 lb/ft
And the standard box didnt last long at all, infact it blew up on the road test after the final mapping
And the standard box didnt last long at all, infact it blew up on the road test after the final mapping
I think you mean tractive effort of 1800 lb's Dave
#30
Originally Posted by minty
Dave was your box an RA as your name suggests ?? i am about to do a similar thing and am having serious thoughts about the gearbox strength in my RA. Are UK 6 Speed boxes stronger than RA ones then ????