2.5 Conversion
22 September 2004, 12:02 PM
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I'm not about to post my prices on here so that everyone can suddenly be a fiver cheaper. Suffice to say that our rebuilding record speaks for itself in terms of quality and the most expensive standard rebuild that we have ever done was on a 22B at a total cost of £4200 plus VAT it was for an insurance company and we just couldn't think of anything more to add on !
At the lower end of the scale a full, warranted rebuild from me on a 92 - 96 WRX or UK turbo is £1600 without cutting any corners. Fitting is extra.
I do worry about the comments that a 2,5 conversion is straight forward. What about the compression ratio?, to replace the bottom end with one 25% bigger is NOT a straight bolt on. There are enough issues with big end failure through overloaded crank shells to want to do something about the compression.
What about injectors? What about cooling an engine 25 % bigger? What about fuel supply? Shall I go on?
It's not complicated but it is something that needs thought and I repeat it cannot be done cheaply as an alternative to a straight rebuild.
David APi Engines / APi Impreza
At the lower end of the scale a full, warranted rebuild from me on a 92 - 96 WRX or UK turbo is £1600 without cutting any corners. Fitting is extra.
I do worry about the comments that a 2,5 conversion is straight forward. What about the compression ratio?, to replace the bottom end with one 25% bigger is NOT a straight bolt on. There are enough issues with big end failure through overloaded crank shells to want to do something about the compression.
What about injectors? What about cooling an engine 25 % bigger? What about fuel supply? Shall I go on?
It's not complicated but it is something that needs thought and I repeat it cannot be done cheaply as an alternative to a straight rebuild.
David APi Engines / APi Impreza
22 September 2004, 12:21 PM
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David, nice points.
Rob, whilst i agree with you and mark to an extent, even as a straight bolt in replacement, no other fussing, it is likely to be around 320/320, and IMO if gearboxes are on a nife edge at that point. Suddenly it may not be cheap!
They are all ifs, which you inevitably try to cover.
Rob, whilst i agree with you and mark to an extent, even as a straight bolt in replacement, no other fussing, it is likely to be around 320/320, and IMO if gearboxes are on a nife edge at that point. Suddenly it may not be cheap!
They are all ifs, which you inevitably try to cover.
22 September 2004, 01:07 PM
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Originally Posted by U WOT!
I've just had the engine go bang in my 94wrx sti. I am very reluctant to spend money fixing it to end up with the same car as i had before, so hae decided now is the best time to start tuning. Ive been told that its the short block that needs replacing so want to go for the 2.5 conversion. I've looked at scoobyclinic and a few of the others but don't know if the price quoted includes all that is needed like the FMIC etc. What is needed and what are the rough prices. Also who do you recommend around the north hampshire. I'm in Fleet near reading, guildford etc.
Cheers for any help and i have tried the search before anyone suggests it.
Cheers for any help and i have tried the search before anyone suggests it.
you could be a little more maverick and source an AJP v8 (TVR) 4.2 - only 21 inch cube and all alloy - cant cost any more - no lag - adequate power - best part of 400 ft lb - make bellhousing adapter - recoup development cost by selling copies on scoobynet - sump clearance? - length, height and weight should all be ok - make the ultimate Impreza hybrid?
Or use the 4.5 AJP with Red Rose upgrade in a new shape 6 speed with over 450lb ft and trounce the new EVO 400 FQ - not to mention a Pagani Zona or two....
Dreaming? - Perhaps not? - All the intercooler and turbo costs and probs vanish - the engine comes complete and doesnt need upgrading - fantastic throttle response and therefore chassis adjustability when sliding (no turbo rush to anticipate)
Come on you top tuners - think outside the box and be a little radical - TVR Power can even supply with fully mapped Nitrous if you want over 500 bhp...................
22 September 2004, 01:15 PM
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Originally Posted by GRIFF007
you could be a little more maverick and source an AJP v8 (TVR) 4.2 - only 21 inch cube and all alloy - cant cost any more - no lag - adequate power - best part of 400 ft lb - make bellhousing adapter - recoup development cost by selling copies on scoobynet - sump clearance? - length, height and weight should all be ok - make the ultimate Impreza hybrid?
Or use the 4.5 AJP with Red Rose upgrade in a new shape 6 speed with over 450lb ft and trounce the new EVO 400 FQ - not to mention a Pagani Zona or two....
Dreaming? - Perhaps not? - All the intercooler and turbo costs and probs vanish - the engine comes complete and doesnt need upgrading - fantastic throttle response and therefore chassis adjustability when sliding (no turbo rush to anticipate)
Come on you top tuners - think outside the box and be a little radical - TVR Power can even supply with fully mapped Nitrous if you want over 500 bhp...................
Or use the 4.5 AJP with Red Rose upgrade in a new shape 6 speed with over 450lb ft and trounce the new EVO 400 FQ - not to mention a Pagani Zona or two....
Dreaming? - Perhaps not? - All the intercooler and turbo costs and probs vanish - the engine comes complete and doesnt need upgrading - fantastic throttle response and therefore chassis adjustability when sliding (no turbo rush to anticipate)
Come on you top tuners - think outside the box and be a little radical - TVR Power can even supply with fully mapped Nitrous if you want over 500 bhp...................
Or maybe the engine from the Q E ll that runs on diesel so it'd be more economic.
That far enough out of the box for ya!
David APi Engines / APi Impreza
22 September 2004, 01:57 PM
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David,
The quality of your engine rebuilds/work, is not in question here.
Compression is one of the easiest issues to address. Within reason, piston compression height/squish, has little effect on the performance, so it's simply a case of picking the best head gasket to suit the MY heads being used. The same applies when fitting a later short engine to an earlier car/heads, and visa versa.
Big end bearing failure is not due to "compression". Whilst I appreciate rally cars generally run less power, they would normally run much more torque, and boost, and, they run FAR higher compression. 10.5:1 is common.
What about them ? There is no more reason to change injectors in a 2.5lt, than there is in a 2.0lt. Injectors only need to be changed if you're looking for quite a bit more power than standard. This applies to any size engine, injector combination.
There's nothing wrong with the stock rad'. It's more than capable of cooling a 2.5lt. It's easy to test, just try running the engine without the thermostat, and see what happens.
Same applies as with the injectors. If you're running a totally stock 2.0lt set up, the stock pump should be fine. If you start tuning the 2.0lt, the merits of fitting an up rated pump, and reg' are well proven.
This applies to an increase in "power", not because you're increasing engine size.
A 2.5lt can be tuned to run no more power, or torque than a 2.0lt, or people can choose to take advantage, and tune it to what ever level they can afford.
To me, the biggest hassle is not the engine swap, but having to get the log book changed, and for some people, the attitude of their insurance company.
Mark.
The quality of your engine rebuilds/work, is not in question here.
What about the compression ratio?, to replace the bottom end with one 25% bigger is NOT a straight bolt on. There are enough issues with big end failure through overloaded crank shells to want to do something about the compression.
Big end bearing failure is not due to "compression". Whilst I appreciate rally cars generally run less power, they would normally run much more torque, and boost, and, they run FAR higher compression. 10.5:1 is common.
What about injectors?
What about cooling an engine 25 % bigger?
What about fuel supply?
This applies to an increase in "power", not because you're increasing engine size.
A 2.5lt can be tuned to run no more power, or torque than a 2.0lt, or people can choose to take advantage, and tune it to what ever level they can afford.
To me, the biggest hassle is not the engine swap, but having to get the log book changed, and for some people, the attitude of their insurance company.
Mark.
22 September 2004, 02:43 PM
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Originally Posted by R19KET
David,
The quality of your engine rebuilds/work, is not in question here.
Compression is one of the easiest issues to address. Within reason, piston compression height/squish, has little effect on the performance, so it's simply a case of picking the best head gasket to suit the MY heads being used. The same applies when fitting a later short engine to an earlier car/heads, and visa versa.
Big end bearing failure is not due to "compression". Whilst I appreciate rally cars generally run less power, they would normally run much more torque, and boost, and, they run FAR higher compression. 10.5:1 is common.
What about them ? There is no more reason to change injectors in a 2.5lt, than there is in a 2.0lt. Injectors only need to be changed if you're looking for quite a bit more power than standard. This applies to any size engine, injector combination.
There's nothing wrong with the stock rad'. It's more than capable of cooling a 2.5lt. It's easy to test, just try running the engine without the thermostat, and see what happens.
Same applies as with the injectors. If you're running a totally stock 2.0lt set up, the stock pump should be fine. If you start tuning the 2.0lt, the merits of fitting an up rated pump, and reg' are well proven.
This applies to an increase in "power", not because you're increasing engine size.
A 2.5lt can be tuned to run no more power, or torque than a 2.0lt, or people can choose to take advantage, and tune it to what ever level they can afford.
To me, the biggest hassle is not the engine swap, but having to get the log book changed, and for some people, the attitude of their insurance company.
Mark.
The quality of your engine rebuilds/work, is not in question here.
Compression is one of the easiest issues to address. Within reason, piston compression height/squish, has little effect on the performance, so it's simply a case of picking the best head gasket to suit the MY heads being used. The same applies when fitting a later short engine to an earlier car/heads, and visa versa.
Big end bearing failure is not due to "compression". Whilst I appreciate rally cars generally run less power, they would normally run much more torque, and boost, and, they run FAR higher compression. 10.5:1 is common.
What about them ? There is no more reason to change injectors in a 2.5lt, than there is in a 2.0lt. Injectors only need to be changed if you're looking for quite a bit more power than standard. This applies to any size engine, injector combination.
There's nothing wrong with the stock rad'. It's more than capable of cooling a 2.5lt. It's easy to test, just try running the engine without the thermostat, and see what happens.
Same applies as with the injectors. If you're running a totally stock 2.0lt set up, the stock pump should be fine. If you start tuning the 2.0lt, the merits of fitting an up rated pump, and reg' are well proven.
This applies to an increase in "power", not because you're increasing engine size.
A 2.5lt can be tuned to run no more power, or torque than a 2.0lt, or people can choose to take advantage, and tune it to what ever level they can afford.
To me, the biggest hassle is not the engine swap, but having to get the log book changed, and for some people, the attitude of their insurance company.
Mark.
David
22 September 2004, 03:07 PM
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Phase II heads are certainly fine with either 0.8 or 1.6mm gaskets anyway. Intending to do a Legacy with MY98 heads soon, will need to get the head volumes and deck heights and work it out.
The reliability record of my 2.5 project is not impeccable solely because I pushed it quite hard towards c.480 BHP on relatively high compression using lots of advance on methanol - cylinder pressure probably did it because I had a headgasket go on one side and a small crack in a piston in the other. But with a new pistons kindly supplied from another broken EJ257 user and new headgaskets, the bottom end appears otherwise in good nick to do the Legacy mentioned above. On Optimax at double the car's stock power though, the engine behaves perfectly.
I would caution against fitting forged pistons for reliability unless you know you need them, you could end up with a load more problems, which particularly afflict the daily driver. How well proven are the forged piston options in this engine compared with OEM across:
- several or many cars
- at relatively high power
- for high mileage/time
As far as I can see in the UK on standard EJ257s I have as much mileage as anyone with 15000 miles over 400 BHP. That is still early days. Although I've cracked one piston, I think the engine is vastly under-rated, including the pistons. 480+ BHP
The reliability record of my 2.5 project is not impeccable solely because I pushed it quite hard towards c.480 BHP on relatively high compression using lots of advance on methanol - cylinder pressure probably did it because I had a headgasket go on one side and a small crack in a piston in the other. But with a new pistons kindly supplied from another broken EJ257 user and new headgaskets, the bottom end appears otherwise in good nick to do the Legacy mentioned above. On Optimax at double the car's stock power though, the engine behaves perfectly.
I would caution against fitting forged pistons for reliability unless you know you need them, you could end up with a load more problems, which particularly afflict the daily driver. How well proven are the forged piston options in this engine compared with OEM across:
- several or many cars
- at relatively high power
- for high mileage/time
As far as I can see in the UK on standard EJ257s I have as much mileage as anyone with 15000 miles over 400 BHP. That is still early days. Although I've cracked one piston, I think the engine is vastly under-rated, including the pistons. 480+ BHP
22 September 2004, 03:35 PM
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John, i was catching you up on the mileage front, whilst yours was off the road 
Now well over 7000 thousand, but uprated internals, and pushed fairly hard during those 7000+ miles.
Suspect you and i, are perhaps leading the way with regards to long term testing, i dont know, but we are/were both running high rpm limits of 7500 by all accounts.
Dont know of anyone else who has done that mileage on the 2.5's other than you and i, Scott maybe, but he is quiet these days.
Maybe the standard spec can take it, and in that case it is, as Mark and Rob say, a bargain.
I know my uprated internals have taken a bit of abuse so far, anyone who saw/heard me launcing at TOTB3 will vouch for that, bouncing it off the limiter whilst stationery isnt good for any engine, yet the dope behind the wheel (me) still did it several times!!
Also holding it for more than half a mile bouncin off the limiter in 6th at Scooby Shoot Out, tested it to the extreme, seeing oil temps rise rapidly to 120 degrees.
John, when you guys next having a RR session up your way, as i may take T-Uk's offer up, and would dearly love to drive your car in direct comparison to mine (and vice versa).
Steven
Now well over 7000 thousand, but uprated internals, and pushed fairly hard during those 7000+ miles.
Suspect you and i, are perhaps leading the way with regards to long term testing, i dont know, but we are/were both running high rpm limits of 7500 by all accounts.
Dont know of anyone else who has done that mileage on the 2.5's other than you and i, Scott maybe, but he is quiet these days.
Maybe the standard spec can take it, and in that case it is, as Mark and Rob say, a bargain.
I know my uprated internals have taken a bit of abuse so far, anyone who saw/heard me launcing at TOTB3 will vouch for that, bouncing it off the limiter whilst stationery isnt good for any engine, yet the dope behind the wheel (me) still did it several times!!
Also holding it for more than half a mile bouncin off the limiter in 6th at Scooby Shoot Out, tested it to the extreme, seeing oil temps rise rapidly to 120 degrees.
John, when you guys next having a RR session up your way, as i may take T-Uk's offer up, and would dearly love to drive your car in direct comparison to mine (and vice versa).
Steven
22 September 2004, 03:52 PM
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Originally Posted by APIDavid
OR you could put in an engine from Supermartine Spitfire you'd just need to lengthen the bonnet a bit.
Or maybe the engine from the Q E ll that runs on diesel so it'd be more economic.
That far enough out of the box for ya!
David APi Engines / APi Impreza
Or maybe the engine from the Q E ll that runs on diesel so it'd be more economic.
That far enough out of the box for ya!
David APi Engines / APi Impreza
Now just because you havent tried AJP motors there is no need to be, ahem a little sceptical now is there?!
Rover V8 fits into 944 and makes nice car, so I cant see why the suggestion shouldnt be explored - I for one could be interested - perhaps TVR Power could have a go
22 September 2004, 03:54 PM
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Having been in a 4.2 TVR quite frequently, and the owner of sadi car been in my car, we both conclude that the Scoob 2.5 turbo has more grunt!
22 September 2004, 04:00 PM
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David,
That's not quite what I said. John Banks last post gives his experiences, and he only had issues when he started to push it far more than most.
I would say that the later heads work better that the earlier, and seem to take more ignition. I know that Pat has found on some cars, he can't get in as much ignition as he'd expect, but the same is true of some 2.0lt cars we've come across.
I've had less experience mapping the 2.5's than Pat, and the ones that I've done, have only been running VF turbo's at low boost, giving circa 330bhp/ftlbs, and I've not had a problem.
Mark
That's not quite what I said. John Banks last post gives his experiences, and he only had issues when he started to push it far more than most.
I would say that the later heads work better that the earlier, and seem to take more ignition. I know that Pat has found on some cars, he can't get in as much ignition as he'd expect, but the same is true of some 2.0lt cars we've come across.
I've had less experience mapping the 2.5's than Pat, and the ones that I've done, have only been running VF turbo's at low boost, giving circa 330bhp/ftlbs, and I've not had a problem.
Mark
22 September 2004, 04:04 PM
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Originally Posted by P20SPD
Having been in a 4.2 TVR quite frequently, and the owner of sadi car been in my car, we both conclude that the Scoob 2.5 turbo has more grunt!
I just feel that the 2.5 tuning seems a little more complex for similar torque?
Whereas the AJP would be more than a little different if you are going extreme
Anybody read about the production FQ400 beating the Pagani?
22 September 2004, 04:47 PM
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Steven, yes a comparison would be very interesting. I think what we would see is they would do similarly until the last 2000 RPM when you would have about 10% more power, I think you wouldn't lose anything in spool up either. I think mine is about 440 BHP at present. I've got it quite rich at 11.0-11.2:1, ignition is tame - bottom green on knocklink comes on at 6000 RPM, never any more, rev limit is now 7300 on this motor, boost is 20 PSI until 6000 RPM tapering to 18.5 PSI at 7000 RPM.
22 September 2004, 09:37 PM
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Steven - How about 30th october at Dastek in Fife? See Scotland forum - Dastek Re-run thread. Would be great to see you there and I'm sure there would be space for an "interesting" Yorkshire wagon
22 September 2004, 10:03 PM
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Callum, any other day and that would be a cert. Its my wifes birthday that day, and we have a meal booked in Leeds at a fancy restaraunt. Sorry 
Any others, let me know.
Any others, let me know.
22 September 2004, 10:20 PM
#52
I was intending to run at PE on the 30th......
Anyway as for cost of a fully specced car, it can be done on a shoestring, mine cost me less than £13000 (inc car purchase) in parts alone but I've done all the work myself, traded, begged, borrowed, stolen (jk), stuff to get this far. If you wanted to give it to someone for them to do, then say goodbye to about £15000 plus the cost of the car.
However, EJ257 as a replacement for a broken 2.0 is a good idea as a low powered car. With moderate boost, and medium torque, you will end up with a flexible nice to drive package. Only when you want to push it further will you see the problems. But an exchange short motor from Subaru or someone like API is still your cheapest bet.
Paul
Anyway as for cost of a fully specced car, it can be done on a shoestring, mine cost me less than £13000 (inc car purchase) in parts alone but I've done all the work myself, traded, begged, borrowed, stolen (jk), stuff to get this far. If you wanted to give it to someone for them to do, then say goodbye to about £15000 plus the cost of the car.
However, EJ257 as a replacement for a broken 2.0 is a good idea as a low powered car. With moderate boost, and medium torque, you will end up with a flexible nice to drive package. Only when you want to push it further will you see the problems. But an exchange short motor from Subaru or someone like API is still your cheapest bet.
Paul
23 September 2004, 08:35 AM
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To give an indication of the torqgue that the 2.5's can chuck out, i timed my car from 80 to 140 in 6th gear at roughly 9 seconds. I am sure Pauls is even quicker, but i was surprised how little time it took to gain that much speed.
23 September 2004, 10:32 AM
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Originally Posted by P20SPD
To give an indication of the torqgue that the 2.5's can chuck out, i timed my car from 80 to 140 in 6th gear at roughly 9 seconds. I am sure Pauls is even quicker, but i was surprised how little time it took to gain that much speed.
23 September 2004, 10:42 AM
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drop it to 4th and boot it, prob between 2 and 3 seconds at a guess, given it has been timed at 7.9 to 90 from a standing start to go on and do 111 in 12.4, which includes a change from 4th to 5th at 100mph, i dont think 2 to 3 seconds is out.
23 September 2004, 01:32 PM
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Griff, I have these from my five speed run 40-90mph in 3rd on AP22 on my old five speed box with similar power and torque to present, with a passenger, in the wet, damn I really used to like that 3rd gear :
mph time(s)
40.0 0.00
50.0 0.93
60.0 1.77
70.0 2.64
80.0 3.62
90.0 4.83
:mph time(s)
40.0 0.00
50.0 0.93
60.0 1.77
70.0 2.64
80.0 3.62
90.0 4.83
