rosssti

iTrader: (1)

I'm in the market for an Sti engine for my UK300, I've been running close to 400bhp on the standerd wrx engine, I've had 18 months of trouble free motoring, but now I've a small knock on the bottom end and don't know how long Itl last, I just need to no what Sti engine will take the most bhp with bolt ons in its standerd form?

I've heard of people getting arround 500 on the 2.0 Sri engine but no nothing about what the 2.5 will take, any info would be great.....

s70rjw

iTrader: (2)

2.0 has less reliability issues.
Some 2.5 STI owners suffer head gasket and piston problems.

Terminator X

iTrader: (7)

Jap 2.0 UK 2.5 boo!

TX.

Edit - now read your post 2.1 will be best bet, seems a good mix between the two engines. Peeps on here running 500+ on them ...

craigfturbo2000

friend of mine has had 2.0 import hawk eye sti and 2.5 uk sti, says 2.0 is miles better!

Flight

Depends what you want. The 2.5 won't (supposedly) take as much power. But it's easy mods (exhaust, filter and remap) to get a safe 330bhp-350bhp and you get lots of low end grunt (torque). Which for me makes the driving more effortless (eg, 5th or 6th on the motorway pulls very well). The 2.0 though will give you more of that turbo-shove, which is what some hanker after. Ultimately, not much in it unless you want 400bhp+. In which case go the 2.0 route.

rosssti

iTrader: (1)

I deffo need more power than I have now, I no a guy that's nearly 500 on a stock 2.0, I think that's what I'm going to go for 2.0 sti long engine.

B4D HK

iTrader: (15)

2.0

Paulo P

iTrader: (42)

2.0 for me too, 2.5's spool the bigger turbos easier but don't seem to make much more power and don't seem as reliable as the late 2.0's. I'm having mine built using a 2005 2.0 short motor

TimH

iTrader: (11)

Not every 2.0l STi engine will take 500bhp reliably - a "classic" certainly won't.

Later (maybe 03 onwards) 2.0l may well, but it's not a given as some live, some fail. '05 onwards JDM's probably have the strongest internals.

TH3_5T1G

iTrader: (15)

I have a 2.0 sti bottom end for sale

2.5's have more frequent head gasket issues and the liners crack fairly easily at higher power. Not being biased but a 2.0 beats the 2.5 everytime in my book, bar the torque increase of course

TimH

iTrader: (11)

Wouldn't argue with that - if I was building again, I would go 2.1 if on a budget, or 2.35 if money was no object

Maz

iTrader: (34)

The earlier non twin scroll JDM STI had true forged pistons the later ones had hypereutectic ones which were not quite as resistant to det.

Shaun

The above comment maybe true but I'm sure none of us aim to achieve DET in our set-ups do we, regardless of what engine we have. I find the fact fairly mute tbh, but some may argue that.

MattyB1983

iTrader: (51)

2005 JDM STI bottom end in my classic at circa 400. No issues so far for me (runs off and touches a piece of wood), heard of guys running 500+ with them. 400 seems to be a pretty safe number for them.

Maz

iTrader: (34)

It was a MOOT point yes. The point being that the earlier pistons were true forged items and the later ones weren't.

New_scooby_04

iTrader: (4)

Having had both a 2.0 and 2.5 I'd say for a road car 2.5 everytime if you don't intend to go beyond the high 300s. They spool from nothing and produce better torque. If you want to get reliably into the 400s you'll be looking at a forged 2.5 which makes for an awesome road car. My forged 2.5 developes 1 bar at 2700 and produces 473/482 ideal road car; it has guts everywhere in the rev range and enough power to drive away from all but really expensive exotica. If you want above 500 and/or like a high reving engine, go for a forged 2.0.

Ns04

ditchmyster

iTrader: (7)

I'd say with those numbers there is not very much that will be driving away from you,but am i right in thinking the cost of your build, forged 2.5 and ancillaries is very close to 2.35 money and possibly a bit more than 2.1 as i'm sure you have taken the belt and braces approach

To the op, i'm sure you are aware that going over 400bhp in a newage is going to cost, not sure what spec you already have to run close to 400bhp on a uk300 how much of it is re-useable, but i'm thinking your going to need turbo,frontmount, bigger brakes, injectors the list goes on and on if your going to do it properly, not suggesting you can't afford it, just that do you want to afford it.

My point being that 400bhp is a bloody quick newage, now you can spend 3/3.5k and have that very reliable or your looking at circa 10k+ to go over that and get similar reliability, just some food for thought

And as your post mentions standard engine and bolt on's and nothing about actually building an engine i assume your thinking of swopping your bottom end, if so the strongest standard bottom end is the jdm sti but i would suggest you don't aim for much more than 400bhp and one of those usually cost around the £1500 mark used.

If i were you i would go 2.1 and re-use your own block, as that will give you a zero miles engine that will take anything you throw at it up to and above 500 and can also be done in stages, as any engine builder worth their salt will have to strip what ever engine you buy and rebuild it anyway so you may as well have them build you a 2.1 as the cost will be much of a muchness.