2.0 or 2.5 what's better?
16 February 2009, 08:05 PM
#31
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16 February 2009, 10:59 PM
#39
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ok lads..
howm much torque can the 6 speed boxes take?
second question how much for a 2.0 twin scrool turbo engine in my mates version 5 wagon? big end went last night
howm much torque can the 6 speed boxes take?
second question how much for a 2.0 twin scrool turbo engine in my mates version 5 wagon? big end went last night
16 February 2009, 11:11 PM
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The 6 speed boxes are rated at around the 450lb mark, so quite good 
and you can pick up a complete twin scroll engine from 3.5k-4k with virtually no miles on from a breaker.
Pavlo, they quote at power figure (torque and bhp) at the wheels, do you quote yours at the wheels also?
Tony
and you can pick up a complete twin scroll engine from 3.5k-4k with virtually no miles on from a breaker.Pavlo, they quote at power figure (torque and bhp) at the wheels, do you quote yours at the wheels also?
Tony
17 February 2009, 09:24 AM
#43
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[QUOTE=dynamix;8515981]Absolutely owned them 
2.5 is the way forward as almost all the top tuners have recognised.
correct me if im wrong then but what won totb, sso and time attack? was that a 2.0? and has it blown up?
2.5 is the way forward as almost all the top tuners have recognised.
correct me if im wrong then but what won totb, sso and time attack? was that a 2.0? and has it blown up?
17 February 2009, 09:34 AM
#45
Tony, I'll be blunt here. You're talking nonsense.
The 2.5 isn't a lazy engine that doesn't like to rev. My old car (standard 2.5 bottom end, STI 5 heads and a rotated GT30R setup) quite happily revved to 8krpm, It made 450 bhp @1.4 bar and was very very driveable.
I've had a 400bhp 2.0L and and then swapped to 2.5, it's one of the best mods you can do on a scooby. As for them being weak, Duncans and Shauns have seen in excess off 540bhp with no problems liner wise.
Granted the 2.0L CDB is the strongest platform to start from but unless you're aiming for massive power the 2.5 is a good option.
I've gone for the best of both worlds on my current build a 2.0L closed deck block bored and sleeved to 2.5L.
I wouldn't have gone to the expense of doing that if the 2.5 was a lazy engine that doesn't like to Rev.
The 2.5 isn't a lazy engine that doesn't like to rev. My old car (standard 2.5 bottom end, STI 5 heads and a rotated GT30R setup) quite happily revved to 8krpm, It made 450 bhp @1.4 bar and was very very driveable.
I've had a 400bhp 2.0L and and then swapped to 2.5, it's one of the best mods you can do on a scooby. As for them being weak, Duncans and Shauns have seen in excess off 540bhp with no problems liner wise.
Granted the 2.0L CDB is the strongest platform to start from but unless you're aiming for massive power the 2.5 is a good option.
I've gone for the best of both worlds on my current build a 2.0L closed deck block bored and sleeved to 2.5L.
I wouldn't have gone to the expense of doing that if the 2.5 was a lazy engine that doesn't like to Rev.
17 February 2009, 09:37 AM
#46
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cheers , wernt a dig, just curious why 1 engine is better than the other when the 2.0 won the 3, just confusing.
17 February 2009, 09:39 AM
#47
RCM have stuck with a 2.0 CDB because they run HUGE amounts of NOS. The 2.5 would not cope with that in std form.
Zen's and other's 2.5 engines have got great power without having to go down the NOS route and have shown that the 2.5 is a very reliable platform to get performance without having to suffer the lag that the 2.0 does.
Zen's and other's 2.5 engines have got great power without having to go down the NOS route and have shown that the 2.5 is a very reliable platform to get performance without having to suffer the lag that the 2.0 does.
17 February 2009, 09:42 AM
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RCM have stuck with a 2.0 CDB because they run HUGE amounts of NOS. The 2.5 would not cope with that in std form.
Zen's and other's 2.5 engines have got great power without having to go down the NOS route and have shown that the 2.5 is a very reliable platform to get performance without having to suffer the lag that the 2.0 does.
Zen's and other's 2.5 engines have got great power without having to go down the NOS route and have shown that the 2.5 is a very reliable platform to get performance without having to suffer the lag that the 2.0 does.
17 February 2009, 10:29 AM
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It depends on what kind of drive you're after IMHO. The 2 litre loves being revved and needs a bit more work to get going, whereas the 2.5 produces a much more lazier drive so may be better suited to some for road use. Personally I having come from Honda VTEC units I'm used to working an engine to keep its in it sweet spot. I get more satisfaction from it which is why I prefer the drive of the 2 litre.
The 2.5 is the weaker unit of the two. It was only introduced into Europe to comply with the forthcoming Euro IV emissions, whereby the 2 litre would have needed expensive modding.
Yes the 2.5 produces more torque, it's bound to, it has a higher capacity, but the way in which a twin scroll unit delivers its power may be preferable to some. But how many 2.5 units out there would cope with 400-450bhp on standard internals? Erm, none would be my answer. Yet we know there are a few Spec C's on this forum putting out that kind of power still on standard internals, but obviously with the obligatory turbo upgrade. The 2 litre also features a stronger valve train, nitrided and cross-drilled crank, larger ported heads and a more aggressive inlet cam, not to mention the stainless headers versus the cast items of the 2.5 unit.
For track use the 2 litre is definitely the better choice. It loves being revved and on track you are most likely to be in the higher rpm range most of the time. Hence the reason why Honda VTEC units work better on track rather than on the road.
This is a debate that will rage on for all time if you ask me, with each person shouting the merits of each engine, BUT, if you want to look at it from a pure technical viewpoint then the 2 litre IS the better engine, there can be no denying that.
The 2.5 is the weaker unit of the two. It was only introduced into Europe to comply with the forthcoming Euro IV emissions, whereby the 2 litre would have needed expensive modding.
Yes the 2.5 produces more torque, it's bound to, it has a higher capacity, but the way in which a twin scroll unit delivers its power may be preferable to some. But how many 2.5 units out there would cope with 400-450bhp on standard internals? Erm, none would be my answer. Yet we know there are a few Spec C's on this forum putting out that kind of power still on standard internals, but obviously with the obligatory turbo upgrade. The 2 litre also features a stronger valve train, nitrided and cross-drilled crank, larger ported heads and a more aggressive inlet cam, not to mention the stainless headers versus the cast items of the 2.5 unit.
For track use the 2 litre is definitely the better choice. It loves being revved and on track you are most likely to be in the higher rpm range most of the time. Hence the reason why Honda VTEC units work better on track rather than on the road.
This is a debate that will rage on for all time if you ask me, with each person shouting the merits of each engine, BUT, if you want to look at it from a pure technical viewpoint then the 2 litre IS the better engine, there can be no denying that.
17 February 2009, 10:32 AM
#51
It depends on what kind of drive you're after IMHO. The 2 litre loves being revved and needs a bit more work to get going, whereas the 2.5 produces a much more lazier drive so may be better suited to some for road use. Personally I having come from Honda VTEC units I'm used to working an engine to keep its in it sweet spot. I get more satisfaction from it which is why I prefer the drive of the 2 litre.
The 2.5 is the weaker unit of the two. It was only introduced into Europe to comply with the forthcoming Euro IV emissions, whereby the 2 litre would have needed expensive modding.
Yes the 2.5 produces more torque, it's bound to, it has a higher capacity, but the way in which a twin scroll unit delivers its power may be preferable to some. But how many 2.5 units out there would cope with 400-450bhp on standard internals? Erm, none would be my answer. Yet we know there are a few Spec C's on this forum putting out that kind of power still on standard internals, but obviously with the obligatory turbo upgrade. The 2 litre also features a stronger valve train, nitrided and cross-drilled crank, larger ported heads and a more aggressive inlet cam, not to mention the stainless headers versus the cast items of the 2.5 unit.
For track use the 2 litre is definitely the better choice. It loves being revved and on track you are most likely to be in the higher rpm range most of the time. Hence the reason why Honda VTEC units work better on track rather than on the road.
This is a debate that will rage on for all time if you ask me, with each person shouting the merits of each engine, BUT, if you want to look at it from a pure technical viewpoint then the 2 litre IS the better engine, there can be no denying that.
The 2.5 is the weaker unit of the two. It was only introduced into Europe to comply with the forthcoming Euro IV emissions, whereby the 2 litre would have needed expensive modding.
Yes the 2.5 produces more torque, it's bound to, it has a higher capacity, but the way in which a twin scroll unit delivers its power may be preferable to some. But how many 2.5 units out there would cope with 400-450bhp on standard internals? Erm, none would be my answer. Yet we know there are a few Spec C's on this forum putting out that kind of power still on standard internals, but obviously with the obligatory turbo upgrade. The 2 litre also features a stronger valve train, nitrided and cross-drilled crank, larger ported heads and a more aggressive inlet cam, not to mention the stainless headers versus the cast items of the 2.5 unit.
For track use the 2 litre is definitely the better choice. It loves being revved and on track you are most likely to be in the higher rpm range most of the time. Hence the reason why Honda VTEC units work better on track rather than on the road.
This is a debate that will rage on for all time if you ask me, with each person shouting the merits of each engine, BUT, if you want to look at it from a pure technical viewpoint then the 2 litre IS the better engine, there can be no denying that.
All of them!! Mine coped with 452 at 1.4 bar for over 10,000 miles on standard internals. I only sold it on as I was doing a 600bhp build
17 February 2009, 10:42 AM
#52
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And surely it also depends on the supporting mods you had fitted ie if you were running an FMIC which allowed for much lower and safer inlet charge temps along with a more efficient turbo that didn't scream it **** off and blow nothing but hot air.
17 February 2009, 11:49 AM
#53
Standard the engines are listed as giving
STi5 2.0 single scroll 280PS @ 6500rpm, 353NM @ 4000rpm
MY05 2.0 JDM twin scroll 280PS @ 6400rpm, 412NM @ 4400rpm
MY08 2.0 JDM twin scroll 308PS @ 6400rpm, 422NM @ 4400rpm
MY08 2.5 300PS @ 6000rpm, 407NM @ 4000rpm
Last edited by johnfelstead; 17 February 2009 at 07:26 PM.
17 February 2009, 01:08 PM
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The 6 speed boxes are rated at around the 450lb mark, so quite good and you can pick up a complete twin scroll engine from 3.5k-4k with virtually no miles on from a breaker.
Pavlo, they quote at power figure (torque and bhp) at the wheels, do you quote yours at the wheels also?
Tony
and you can pick up a complete twin scroll engine from 3.5k-4k with virtually no miles on from a breaker.Pavlo, they quote at power figure (torque and bhp) at the wheels, do you quote yours at the wheels also?
Tony
what power are they capable off? reliably..
17 February 2009, 01:43 PM
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This is a graph for a spec C
Full de cat
RCM K&N
3 port
Uprated acuator
Does any one have a uk sti 2.5 with the same mods with a graph
Full de cat
RCM K&N
3 port
Uprated acuator
Does any one have a uk sti 2.5 with the same mods with a graph
Last edited by micahmoor; 17 February 2009 at 01:52 PM.
17 February 2009, 02:53 PM
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IMO it depends where you start from.
If you're starting from owning a classic with a knocking bottom end, then the simplest way to get a more driveable, potentially(!?) more reliable car is to bung a 2.5 bottom end in. It'll run similar power with less boost, it'll spool earlier and it'll be more driveable off boost. Only caveats to this I can think of are purist thinking and costs/insurance costs etc.
If you're starting from having no Impreza and a healthy bank balance. Then you drive all three types form an opinion and make your choice.
J.
If you're starting from owning a classic with a knocking bottom end, then the simplest way to get a more driveable, potentially(!?) more reliable car is to bung a 2.5 bottom end in. It'll run similar power with less boost, it'll spool earlier and it'll be more driveable off boost. Only caveats to this I can think of are purist thinking and costs/insurance costs etc.
If you're starting from having no Impreza and a healthy bank balance. Then you drive all three types form an opinion and make your choice.
J.
17 February 2009, 04:05 PM
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