hi, i am getting ready to buy my third impreza, first one was a classic wrx, and second a 2004 wrx sti type uk, i am currently looking at around a 2007 sti hawkeye model, with a 2.5 engine. which is better 2l or 2.5l.

 

Question is impossible to answer as it totally depends on what you want from the car.

 

pound for pound which is the best to tune? is either any stronger? is there more potential in the bigger cc?

 

If it was me and I was lookin for a hawk then I would be looking for a 2.0 jdm twinscroll model is my honest opinion, if I was set on a 2.5 then I would be looking for one that has been rebuilt using forged pistons and uprated headbolts and gaskets as a minimum ( because I like to drive them ) and having heard of all the problems 2.5 seem to receive then I would not buy a standard one, unless you are a forgiving soul and have great amounts of mechanical sympathy, and even then there are reports of them letting go.

I'm not saying they ain't reliable because there are many owners on here that can vouch that they are! It depends on what you want from the car and if it is going to get a hard life or not IMO, but for me I don't think I could buy a standard 2.5 after listening to the reports as I would be kicking myself if it broke a few miles down the road and had to fork out for an expensive rebuild, especially when you could have put another £1000 in to a car and bought one that has been sorted previously.

My advice would be to drive both models and see what you like, the torque of the 2.5 is great low down mind I must be honest and I have been in a few now, setup correctly with the right engine components make for a real nice going road car with low down boost and plenty of torque to get you moving, but then my jdm twinscroll blob gets up and goes with very minimal effort, I think a sorted 2.5 and a similar spec twinscroll with same kind of mods won't be too far apart from each other IMO.

 

I was in this situation. Early hawk or blob. I've gone for the blob as I know if I bought the Hawk, I would always be waiting for it to break.

 

2.5 isn't known for reliability, my new 2.5 wrx spat a piston and im buying it as a rebuilt engine. does allow for forging though

2.5 makes a better road car, but anything around 500+ and they are a bit fragile, some survive, some dont. Above 500 bored out closed deck 2.0 are by far a better option due to reliability.

If your not going big power (say up to 450) then a forged 2.5 make buckets of toruqe so great on road.

 

efa

 

cheers for the catch tubs,

should have added, that the block is fragile over 500+ even with forged pistons and uprated rods they arnt great.

standard pistons and rods 350 is pushing it

 

even standard unmodded low mileage 2.5 stis are prone to hg failure, the 2.0 is a stronger and more reliable engine but less torque.

if you want a hawk sti get a jdm version it has a 2.0 engine as the japs dont fit rubbish in there cars.

 

Or buy a blob and spend £1500 on a hawk front end conversion

 

or buy my type r with a 2004 jdm fully built newage 2.0ltr sti motor already fitted and tuned.385 bhp with more available if needed.

 

Nothing wrong with std 2.5 sti rods. good for 450bhp. Pistons and standard head bolds are the weaknesses. I agree with not taking the 2.5 block over 500bhp although the 2010 onwards block has thicker liners so if pinned or the deck closed it should be fine at 550-600bhp.

 

not what i understand from a couple of the big tuners matey, rods max 400 on a 2.5, although always depends how far you want to risk it.

 

I would choose 2.0L,agreed 2.5L engine is awesome engine just is little bit lazier engine than 2.0L or 2.1L,yes making lot more torque,but fragility of the non forged 2.5L,is putting me off

Jura

 

Im running 440/440 on a scd 2.5! Standard crank and rods but forged pistons and cossy Ultra studs ..... goes really well!

Test of time isnt there for me to back it up, but i did alot of research about failures of the 2.5's before i went for it and im of the same opinion as chopperman! .... weak link is the pistons and studs!

If mapped to a point where it NEVER sees det, then standard pistons should be good for 400, but they really dont like any det at all, so getting a good ecu mapped by someone that DEFINATELY knows what theyre doing is invaluable.

 

I went my05 jdm widetrack, strong 2.0 engine, cheaper car tax and better spec. But depends what you want really

 

Well the engine builder who built mine (Mr Finch) told me safe 400, 450 max on std STi rods.
I will stand corrected but i think its revs that tend to break rods rather than power. Its the rapid acceleration and deceleration, i think weight of piston also has a major effect. The way i looked at it is the pre 2010 2.5 liners are not considered safe over 450bhp so forging the rods when keeping below this figure was not worth the money. The 2.5 tends to make it's max power well before the rev limit so is probably kinder to the rods. Mine makes max power at 4200rpm where as my red line is 7000rpm.

 

Thanks to all, personally i think i fancy the newer car, so as a starting point, to end up with around 500, and have a reliable fast road car, with the odd track day in mind, what should i be thinking about first, forging etc and how much should i expect to pay, as well who are the recommended tuners, when i move back home to the uk i will be living in southwest area.

 

Why 500? The cost difference from 450 to 500 is huge. Dont get caught up with pub banter numbers. How it drives and how it makes the power is more important than just big numbers.

 

All that money for 450 - 500 and my good old blob jdm is belting out 453/440 on a standard motor, got to make you think sometimes

 

2.5 would be 453/480,,,

 

True... But you might have to push it back off the dyno

 

not if its built right lol

 

lmfao made me laugh tha did

I reckon a bit of meth and I ain't gonna be too far away from those figures question is do I feel that brave

 

this is exactly why i joined this site again, great advice, so with all this then the jap 2.0 hawkeye is the model for me, are there many in the uk, ive lived in australia for the last year and a half and move back to uk in july, so ive some time to find a good one hopefully.

 

Are there any downsides to owning a jap model in england?

 

nope, other than i dont think it comes with a decent alarm as standard?

 

You wont get any re-call notices and some insurance companys can be difficult i believe.
The main thing i would check is the car has been properly under-sealed. It may also be worth checking its been mapped for UK fuel grades.

 

Only down side to owning a jdm hawk is the extra money it costs to buy one but then again if you have it for a good few years then you will be saving £240 per year for a start on tax alone! Plus they will tend to hold their value better come resale time especially well loved and looked after examples.

I think the insurance thing these days is no real headache tbh, plenty of insurers out there know what they are now, and you have a good few places to get quotes from here on the forum with Keith Michaels, green light, sky etc so I wouldn't let that discourage you

Only thing that I can honestly say is a gripe some times is the shorter ratio box on a long drive, as we have a holiday home in west Wales and compared to my uk spec Sti I use more fuel on the same run sitting at the same speed, I can use less by sitting 10mph or so less so the revs are lower but its a ballache tbh as the revs are on 3.5kish at 70 in 6th in my jdm where as it was around 27/2800 rpm at 70 in the uk model so was better on a run sat at the speed limit, but I can live with that I love my car always puts a smile on my face and that's what matters