2.5 engine into my bugeye WRX?
07 June 2012, 01:55 PM
#1
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2.5 engine into my bugeye WRX?
Hi Guys,
i've recently converted my bugeye WRX to twinscroll (which i'm REALLY happy with, for now!) and the next step in my plan is to upgrade my gearbox to a 6.
But, as always, i'm now thinking about the next step after the gearbox!
I'm wondering, is it quite straight forward to swap my engine for a 2.5? (from maybe a legacy? As these are cheaper than the Hawk engines) is it just a case of swapping the blocks and heads then remap?
I take it a twinscroll would be a good match for a 2.5?
I've done a search and it seems most people on here dont do this conversion, and go for stroker conversion or fully forged?
I'm after a REALLY quick (or quicker) road car, and not to bothered about top end speed and track days.
But, i'm looking for the best value for money option!
Just thinking about it at the moment, so engine work probably wont happen until the end of the year.
As always, everyones opinions are appreciated
i've recently converted my bugeye WRX to twinscroll (which i'm REALLY happy with, for now!) and the next step in my plan is to upgrade my gearbox to a 6.
But, as always, i'm now thinking about the next step after the gearbox!
I'm wondering, is it quite straight forward to swap my engine for a 2.5? (from maybe a legacy? As these are cheaper than the Hawk engines) is it just a case of swapping the blocks and heads then remap?
I take it a twinscroll would be a good match for a 2.5?
I've done a search and it seems most people on here dont do this conversion, and go for stroker conversion or fully forged?
I'm after a REALLY quick (or quicker
) road car, and not to bothered about top end speed and track days.But, i'm looking for the best value for money option!
Just thinking about it at the moment, so engine work probably wont happen until the end of the year.
As always, everyones opinions are appreciated
07 June 2012, 02:02 PM
#2
Straight forward, but don't use a legacy engine, they are not upto the job.
Use an STi short motor, with decent pistons and you'll be good to go with your current turbo set up.
2.1 strokers are all the rage at the moment, but still don't compare to the 2.5 for torque and fast road calability. IMO.
Use an STi short motor, with decent pistons and you'll be good to go with your current turbo set up.
2.1 strokers are all the rage at the moment, but still don't compare to the 2.5 for torque and fast road calability. IMO.
07 June 2012, 02:07 PM
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Straight forward, but don't use a legacy engine, they are not upto the job.
Use an STi short motor, with decent pistons and you'll be good to go with your current turbo set up.
2.1 strokers are all the rage at the moment, but still don't compare to the 2.5 for torque and fast road calability. IMO.
Use an STi short motor, with decent pistons and you'll be good to go with your current turbo set up.
2.1 strokers are all the rage at the moment, but still don't compare to the 2.5 for torque and fast road calability. IMO.
I'm just in the process of moving house, as soon as thats out the way i'm going to concentrate on getting a 6 speed. I see you have one for sale, so might be in touch with you about that in a few weeks (depending on how the sale of my place goes, the buyers have re-negotiated twice!).
07 June 2012, 02:46 PM
#4
Sounds like you want to take the same route as i already have and its a great road setup!
SCDB EJ257, standard crank and rods, forged pistons, stiV3 heads .... good for 450/410 if mapped right and kept away from det!
Id second what E_M_B says, the stroked 2l's are good, but a decent 2.5 can be epic!
No replacement for displacement! When your at engine building time, if you have the block apart rather than just fitting a short engine, get the liners of the SCDB 2.5 pinned and youll then be future proofed for going even further!
(just avoid the ODB 2.5's like a herpes upped disco fanny ..... liners are too thin to cope with any boost!)
SCDB EJ257, standard crank and rods, forged pistons, stiV3 heads .... good for 450/410 if mapped right and kept away from det!
Id second what E_M_B says, the stroked 2l's are good, but a decent 2.5 can be epic!
No replacement for displacement! When your at engine building time, if you have the block apart rather than just fitting a short engine, get the liners of the SCDB 2.5 pinned and youll then be future proofed for going even further!
(just avoid the ODB 2.5's like a herpes upped disco fanny ..... liners are too thin to cope with any boost!)
07 June 2012, 02:46 PM
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I've fitted a Sti 10 short block into my classic. It is fairly straight forward and easy to do heads inlet manifold and ancillaries are all the same as before but I now have fantastic torque and it pulls excellent through every gear drives completely different to a 2 litre car now. I had mine remapped only to 310/340 and it keeps up with cars that have 40/50bhp more
07 June 2012, 03:26 PM
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Going from twinscroll (better if you have avcs 
) to a 2.5, you will be disappointed (I was when i tried a standard 2.5 v my standard 2ltr twinscroll), more lag, not as responsive etc, but if you go 2.5 and twinscroll, better, but you will need to uprate the internals of the 2.5.
Tony
) to a 2.5, you will be disappointed (I was when i tried a standard 2.5 v my standard 2ltr twinscroll), more lag, not as responsive etc, but if you go 2.5 and twinscroll, better, but you will need to uprate the internals of the 2.5.Tony
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08 June 2012, 07:37 AM
#9
^ another SN dangerous sweeping statement!
The way to a long living and reliable engine is to build the mechanical bits as strong as you can, then boost and map it to 80% of the theoretical capability of those mechanical bits!
Your approach sounds like its a boost and map it to 120%, and either never use it properly or live in hope!
The way to a long living and reliable engine is to build the mechanical bits as strong as you can, then boost and map it to 80% of the theoretical capability of those mechanical bits!
Your approach sounds like its a boost and map it to 120%, and either never use it properly or live in hope!
08 June 2012, 05:12 PM
#10
I still stand by my comment ODB are good for 500. (Fully rebuilt with pistons and crank/rods) remember its the block in question not the standard STI lump. The power and energy causes distortion of the liner , and extreme cases causes a misshape and then hang up, then failure.
I intend to map mine at 400, somewhat lower than 500 set limits.
Personally I think on standard internals over 300 is pushing it without new pistons on a 2.5 lump.
I intend to map mine at 400, somewhat lower than 500 set limits.
Personally I think on standard internals over 300 is pushing it without new pistons on a 2.5 lump.
08 June 2012, 06:35 PM
#11
Running on EJ20 OBD 490bhp and our engine builder said,will be OK for 550bhp above that CDB or EJ22T is only choice
To OP,TS without the AVCS is pointless and on 2.5L should work well,but at this I would go with 2.1 Stroker and AVCS(UK AVCS should be enough,if you find JDM Big Port heads this will be better choice)
Jumping from 2.1 to the 2.5L and for me 2.5L feels so lazy if I'm comparing to the 2.1 or 2.0L
Jura
To OP,TS without the AVCS is pointless and on 2.5L should work well,but at this I would go with 2.1 Stroker and AVCS(UK AVCS should be enough,if you find JDM Big Port heads this will be better choice)
Jumping from 2.1 to the 2.5L and for me 2.5L feels so lazy if I'm comparing to the 2.1 or 2.0L
Jura
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