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WHY SUCH BHP DIFFERENCE?

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Old 12 January 2003, 09:51 PM
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scoobydu
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I have just bought a jap import my95 wrx which I am very happy with.

As the question asks, why and how do the does my import have 260bhp and uk cars 208bhp, where does this extra power come from. (the same extra power that I love to bits!!!)

Cheers

Al
Old 13 January 2003, 11:58 AM
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RICH WILD
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Hi,

For a start the 95 WRX is rated at 260 PS and the 95 UK at 211 PS (208bhp),
but that is a minor point. The 260 PS is also for a car running 100 RON fuel. On the stuff we get over here you may well not get as much as the 260 quoted.

Also the 95WRX has higher compression than the equivalent UK car and a different ECU.

That's as far as I am aware anyway.

Cheers

Rich

Old 13 January 2003, 12:16 PM
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Tone Loc
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I'd say in practice that there won't be such a difference. From rolling road results i'd say the uk cars and WRXs get about 260bhp or so with induction and full decats.

If you've got a standard MY96WRx i'd be very surprised if you got 240bhp, never mind 260bhp.

Tony.

P.s my 94 WRX got 250bhp with induction kit and full decat (running SUl and OB).
Old 13 January 2003, 02:24 PM
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Pavlo
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Std 96WRX should get at least about 240hp on uk fuel, as demonstrated by the Prodrive edition car which uses almost the exact same setup.

ON the later cars you will be losing power unless you run equivalent fuel. Earlier 93/94 cars seem less different UK to jap.

paul

Old 13 January 2003, 03:16 PM
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jonny gav
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the my95 wrx is a much quicker road car than the my95 uk.

the wrx has a more agressive ecu(260ps), a bigger turbo(TD05) 4:44 diffs lighter ally bonnet and wishbones 1 cat in the exhaust instead of 2 in the uk car.

if you use optimax and NF octane booster you will have no problem getting the full power that is quoted.
Old 13 January 2003, 06:06 PM
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RICH WILD
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Jonny,

95UKs have the TD05 too and the WRXs have 4.111 not 4.444 diffs

But agree about the Optimax and booster bit.

Cheers

Rich

[Edited by RICH WILD - 1/13/2003 6:07:33 PM]
Old 13 January 2003, 06:29 PM
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jonny gav
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rich, are you sure about the 4:111 diffs as my car is a my95 and has 4:444!!!

and the MY95uk car runs a TD04!



[Edited by jonny gav - 1/13/2003 7:03:09 PM]
Old 13 January 2003, 07:39 PM
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scoobydu
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Thanks for the advice guys.

Cheers

Al
Old 13 January 2003, 08:56 PM
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Scott.T
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Early UK's have Ally Bonnets too

UK runs 11.5psi, WRX95 runs 12.7psi, WRX94 Runs 11.5psi
That'll be a major part of it

Prodrive UK (Pre97) runs 13.4psi and gave 256BHP on SUL with ITG, TSL Backbox.
WRX95 at same meet gave 255BHP (with other mods, but not sure what)
Old 13 January 2003, 11:26 PM
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iainalpine
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well hello and welcome scoobydu. sorry i didnt manage in with the rims today, got caught up in glasgow with a problem car. well dave came over tonight and picked up the worst wheel of the lot. also there is a spare set of tyres going with wheels, most are around the 3mm mark. get dave to give me a call 2morow if you want them. also he was saying that you were after an amp and sub. i am also selling a 12" jl audio 12w6 sub and rockford amp. dave has seen these working in my old car. it will sure wake you up in the morning up full pelt.
sorry guys for changing the subject. looks like some good info has been given out
cheers
iain
Old 14 January 2003, 08:35 AM
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RICH WILD
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Jonny,

I'm pretty sure here (not 100%) about the diffs. Normal pre96 WRX runs 4.111 diffs.

If yours is 4.444 (how do you know for sure? have you opened it up?) then the car must have had an STi box and diff swap at some point or the 97 onwards WRX box and diff.

BUT

I am definately sure on this bit: The 95 UK cars have a TD05. My 96UK has a TD05, and my mate's 95UK also has a TD05. The TD04 was used on early WRX wagons with a 90 degree inlet and also on UK cars from 97 onwards when they increased the size of the intercooler and went to front entry. That's one of the reason why 97 onwards cars develop peak torque 800 rpm lower down the rev range. My brother's MY97 originally came with with a TD04 and now runs an MD304. I swear to God mate, they have TD05s.

Cheers

Rich

[Edited by RICH WILD - 1/14/2003 8:38:36 AM]
Old 14 January 2003, 12:25 PM
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Nick200
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I second that >97 = TD05
97 onwards TD04
The only way you could have a TD04 on that year is if it had been replaced sometime in its past...
Old 14 January 2003, 12:42 PM
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IainCam
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Cool

MY94 has a TD05 too, also has the Alloy bonnet and compares quite well with a mates STi (95/96), then again there's only about 10bhp in it between the two of us (I got 287bhp in October )

Theres a difference now to when I bought it as it was standard then but it's decat, filter and Dawes @ 14-15psi at the moment mind you so is his

Only downside is torque, despite the bhp being up the torque isn't up much at all so the STi should still be better "in gear".
Old 14 January 2003, 01:04 PM
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jonny gav
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rich, my car has 4:444 diffs (stamped case) also done an in gear RPM test that came up with the same results.

the 95uk cars i have see had TD04 turbos (both wagons)

never had a look at the saloons though.

iain- what other mods have you got to get that power???

i have a MY95 WRX with full de-cat, BMC carbon air box, dawes running 1.1 bar, sti 6 intercooler and i am running on optimax and NF octane booster.

i am looking at a trip to well lane later in the new year, what sort of power do you think it will be pushing out???


[Edited by jonny gav - 1/14/2003 1:26:39 PM]
Old 14 January 2003, 01:09 PM
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IainCam
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Mine is a wagon too. Looking under the bonnets of the 95/96 STI and MY94 bar the red paint we couldn't see a difference (ECU obviously), only thing we did spot was that he didn't have soundproofing and I did

No idea about diffs and/or ratios though. Never checked.
Old 14 January 2003, 01:22 PM
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RICH WILD
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Jonny,

This is weird then. Has your car had a gearbox/diff swap in its life? Because pre97 WRX should have 4.111s.

Also my mate's 95 UK is a wagon and his has a 90 degree entry TD05, so this is really strange.

I'll put up another thread about this. Dunno about you, but I'd love to know.

Cheers

Rich
Old 14 January 2003, 01:26 PM
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Jay m A
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Just for reference, years ago when optimax wasn't around my 95WRX wass RR'd at PE. It had a full decat and uprated panel filter. Std boost running SUL and OB gave 267 bhp, about right I thought. When calculating the torque they needed to know the rpm @60mph in 4th gear, which was 3800. I know speedos are inaccurate as a guide but this was done on the rollers.

Justin

edit to take out the wrong rpm bit!

[Edited by Jay m A - 1/14/2003 1:30:29 PM]
Old 14 January 2003, 01:33 PM
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jonny gav
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rich, good idea.

nothing is simple with scoobies is it

i have done a search but couldn't find anything about the turbos

there were plenty people asking the same questions but no answers!
Old 14 January 2003, 02:23 PM
  #19  
Attu
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Hope this helps

UK Turbo 1994-1996
3.545:1, 3.900:1 or 4.111:1 (why 3 different ones ?? )
UK Turbo 1996-1998
Same as above
UK Turbo 1998-2000
3.545:1
P1
4.444:1

Jap WRX and STi 1992-1994
4.111:1
WRX 1994-1996
Same as above
WRX 1996-1998
4.444:1
(Wagons for each date are same as Saloon)
WRX Type RA 1992-1994
4.111:1
WRX Type RA 1994-1996
3.900:1 (3.545:1 from Aug 1995)
WRX Type RA 1996-1998
3.545:1
WRX Type RA 1998-2000
Same as above

WRX STi V I Jan 1994-Sep 1994
4.444:1
WRX STi RA V I 1994-1995
Same as above
WRX STi V II
Same as above
WRX STi V III
Same as above
WRX STi V IV
Same as above
WRX STi V V/VI
Same as above
WRX STi S201
Same as above
All STI Type R’s (III, IV, V, VI)
Same as above
WRX STi Type R 22B
4.444:1 (3.900:1 type UK)

All figures from You and your Subaru Impreza Turbo

Andy

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