KEVWRX95

Dave
As we are running the same boost, out of curiosity have you ever had your car on a rolling road??????
I would be interested to know what your figures are?
I will put my car on the rollers over the next couple of months (he says waiting for a very cool day in July or August !!!!!!!!!!!)
I've just got to do another re map (couple more mods) then I should be ready!!!!!!!!!!!!
I know it still depends on what mods you have to go with your 2.5, if you could post up what mods you have I would be very interested.

X SCOOBY sorry to change the thread a little but maybe it will help, if you put your car back together again in the future to see what mods everyone else has done?
Cheers everyone
Kevin.

deadbee

I have a tvr and a scooby, the scooby although handles better and is more fun to drive, they seem to be highly strung and when given a bit of stick from time to time seem to break SO easily,these cars were designed for competition and performance and lets face it i would buy a mondeo if i was driving miss daisy!

DaveBlueRA

Yep been on the rollers a few times. Best so far was 427.1/ 429 (depending if you let the boost build up) and 400 lb/ft

Ben WRX Bug-Eye

As for redlining the car, I think the slight mistake that has been made was to set the limit at 7k and not 6.5k. The standard turbo fitted to the later UK models is small and begins to start losing its efficiency over 5,000rpm. Peak power on the WRX's at least is between 5,500 and 6,000 rpm (6,500 on the STI).


I do drive my car hard whenever the road allows. I do believe the car should and is able to take regularly hitting 6,000rpm without significantly increasing the likely hood of engine failure. What I don't do though is take it much past 6k and I don't usually go into the triple figure speeds. It's quicker to change up well before the redline and it avoids the excessive heat build up from pushing the turbo too hard. As for not going into the hundreds, the bonnet scoop isn't effective due to boundary layer of air effects above 110-120.

Maxed out in 4th/5th so combing the high heat with poor intercooler performance and it can’t cope well. When remapped on the standard turbo the mixture is often leaned out at the higher revs, reducing the safety margin from Subaru's factory over fueling setup, which again adds to the probability of blowups during very high speed runs.


The car isn't happiest over 120. To be safe when maxing it out a FMIC is needed. The car is tough though, as I don't hear of many breaking during track days and there are plenty of Impreza's out there that get well and truely abused without blowup's.

DaveBlueRA

Ok well not entirely true what I said above. Car is now off the road and gonna be having the engine out as it looks like its cracked a piston

RON

P4LNY,
Just out of interest, what g/box are you using at that power??

V5-APS

iTrader: (1)

Looks like Forged pistons are a must have in this engine!!

Fulham71

It depends on how far you want to go !
I have a very nice 341/339 without pistons !
Much better than a 2 litre with the same power

john banks

My pistons seem OK running high 400s BHP.

Tim W

iTrader: (1)

I think it's rather luck of the draw as to whether the particular EJ257 your running has interferance fit pistons or not...I didn't take any chances and had mine honed to give 1 thou clearance on each piston...one of which as standard had 2/10ths of a thou

john banks

Mine was just flung in, not measured

P20SPD

iTrader: (1)

LOL, in some respects thats the best way.

T-uk

I think most of this is your new approach. mapped comfortably to hold 1.4bar with optimax rather than flogging the turbo to death with octane and high boost.

although I still liked the 1.7bar mid-range , the other failures happened at

U WOT!

Whats the difference in terms of strength between the EJ257 and the EJ25?

Tim W

iTrader: (1)

EJ25 is a completely open deck block and was only used in normally aspirated Subarus as standard, so the rods and pistons aren't really intended for use with forced induction.

EJ257 has a similar semi closed deck block, in 2.5 litre guise, to the EJ207 Sti blocks used in new age Sti's. It also has the same rods as the Sti but unique pistons for the larger bore. The EJ257 also only has 0.25mm thick steel liners IIRC, the rest of the support being provided by 11mm thick aluminium alloy bore walls

U WOT!

Would the EJ25 be ok if the pistons and rods were uprated?

T-uk

having a ej25 block in my shed , I would say the bores are too open but then I do not think the ej257 is much better and imo , not worth uprating the internals in

Tim W

iTrader: (1)

Yes an EJ25 would be ok with the right rods and pistons...but as T-UK says they're a bit open at the top so I wouldn't want to run much boost through a standard one...A cheap option would be to fit EJ257 rods and pistons if someone who has changed them on theirs was prepared to sell them. But if you had to buy uprated rods and pistons you probably couldn't run anymore power than someone with a stock EJ257 which would have cost you less in the first place IYSWIM

RB5108

..

X SOOOBY

just looked at my old post out of intrest to add that a engine rebuilder has told me that he cant offer any answer to why my engine popped a piston

so now i am a couple of months down the line and i have a 2.5 axis stage2 with of course forged pistons and as far as i am concerned going the full hog 20g etc.......... the time of not driving my scoob has i supposed made my heart grow fonder of her

lets hope it proves more reliable and no going over 150 not sure if that should be mph or kph

THOMO

not sure if its 150 kph or 150 mph ? it would be a good idea to find out as there is a huge difference in speed

Ralph Wiggum

why is it that the fastest of fast scoobs use a 2.3 bottom end rather than the ej25/257

is it cos in reality, the 2.5 is not up to scratch at big bhp, surely a 2.2 bottom end is better? seems that way from what i see in j-tuner on the scooby shootout

911

AndyF's car is very special.
The 2.3's will have super strong bottom ends and some of the 2.5's will be subaru stock, so good, but not 'special'
Some are fitted by owners with aftermarket pistons/rods and will make big bhp/torque.

The drag cars are purpose built for the job.

If you want to find out more visit the threads in Projects and search 2.5 etc. There is a wealth of real info there and all the detail you could wish for.
Graham.

SNAP

Guys,

Wouldn't you agree that given the complexity of modern engines (ECU, numerous sensors etc) that you can't just shove bits in and out (without access to/knowledge of S/W, etc) and then ask it to take some "abuse"?! Friend doesn't say what mods were carried out. If the engine was spec'd for the States - well, they only do 65mph (just kidding!).

I run a classic STi, no mods, regular oil change/service, and when on the continent cruise all day at 120MPH, often over 140 - no problems.

We get, after all, in excess of 280BHP from a 2ltr engine and an easy sub 5sec to 62. How many 5-seater, sub £25K, cars today can do that? So let us be grateful for what we have, and modify safely with knowledge and real professional help.

LegacySTi

iTrader: (13)

[QUOTE=pslewis]To my mind, and in my opinion, anyone who goes through 3 Engines and 5 Gearboxes cannot drive properly ............. I'm simply saying what EVERYONE is thinking!


0r maybe you just drive yours like a granny. And your well outta order in saying that EVERYONE is thinking this. Subaru engines are soft. Pure and simple!!

strongman

I have been told that the 2.5 engine can not take much over 1.3 bar.
The pistons can not stand any more a will melt,if you want to run bigger bhp
you need to uprate the bottom end.

jameswrx

iTrader: (4)

True, but after being on here and the Mitsubishi lancer register for over 3 years I can say a lot less evo engines expire than impreza ones. I've read a few threads on the MLR about the odd expired lump, but I've seen a number threads on here with pages of people moaning about blown up P1's and sti's.

If I was going for 400+ it'd be a 2.2 stroker Evo.

btw I'm not slating the impreza

SNAP

I would estimate that there have been a lot more Imprezas sold in the UK then EVOs' - we should allow for this. I have personally seen 5 EVO 6s (2 at the dealer) with similar results.

Do you remember the BMW engine (piston) problems of the 90's? BMW blamed it on Venezuelan petrol!

As mentioned before, mods must be carried out with full knowledge of the whole "System". Some will remember that in the early days of imported STI's which were modified/chipped - with fatal results.

Cheers

flat4_ire

i have to agree with legacy man there guys, what do yis be at over there with your cars??? and from what ive seen more guys have probs wth their evos than scoobs! here in ireland neway

flat4_ire

[QUOTE=LegacySTi] read that *** ways, i actually agree with ps lewis on this one all the way guys.. and subaru engines are not soft "legacysti",they can take some abuse! if they are cooled/warmed/serviced properly they will take some beating