MattRus

As the search facility is not working yet and I cannot find any topics specifically for the Forester S Turbo I have started this thread. I am interested to hear from anyone who has experience of modifying this great hybrid machine. I have done some of my own tuning modifications based on knowledge gained from Impreza threads and other rescources.
The MY01 S Turbo is in a different state of tune to that of the Impreza turbos, but is basically the same motor and running gear.
Please let me /us know of any of your experiences.

Butty

iTrader: (2)

Hi Matt?
I seem to remember that Prodrive offered a PPP package for the Forester last year, but I have not seen it advertised recently.
I think it raised the UK output to 200BHP?

I have a 240 BHP jap import and have asked about what I can do with raising its BHP to the WRX 260/280 but got no joy.
I presume the UK Turbo has the same TD04L turbo, but with a UK ECU for 95/98 RON.

All I have done is fit an ITG filter (as per Imprezza) and a Scoobysport rear box. Some torque improvement mid and top range and a lurvely note from the exhaust.
The Dawes device may be the next route, but again no joy on its compatability.

Nick
1997 STB Forester

MattRus

That was quite Butty!
I have precisely the same mod's on my UK Spec. machine. Output as stock is a lowly 185bhp but with 260lbft of torque (depending on which specification you read). Agree with the finds with BB and filter. I have just received a Dawes and will fit it sometime this week.
Oh, I have a SPA digital boost temp. gauge fitted to enable checking when setting up the Dawes.
Other mods include: Prodrive Speedline 17" wheels with Toyo Proxes tyres (fanastic improvement for road use) and a Prodrive (Subaru) 4-pot brake conversion & grooved disc's, again very worthwhile.

simon_prickett

Evo had Prodrive lower their Forester turbo and change the wheels, and maybe other things... that's some time ago now, so can't remember what issue it was in.

Simon.

Butty

iTrader: (2)

Howdy again,
I went down the 17" and 4 pot route. The 2nd hand wheels came with P zeros which were totally unsuitable. Yup, the Proxes are far better.
Have just put on an Imprezza rear 20mm anti roll bar with new plastic links and std bushes and feels really nice. Have not been brave the lift off o/steer yet.

Let us know how you get on with the Dawes
I wondered about which size hole was needed with the different Forester boost levels?

Nick

MattRus

Hi Nick,

guess the Impreza anti-roll bar is a straight swop with the links, I will try and get hold of one (tried to get a 22mm bar from Cobb Tuning in the USA but they do not ship overseas). Thanks for the info. though.
P Zero's where fine when they were brand new but got progressively worse until very bad except on glass smooth roads.
Proxes are much better alround but not quite as much grip IMHO.

Will keep you posted on the Dawes settings etc.. I will hopefully be running some data logging to get some good average readings.
Will also be investigating some ECU modifications, maybe the on efrom Power Engineering.

scoobypig

Friend of mine had ppp put on his forester with the mandatory 17s and hard to find 215/50 p-zeros.
195ps/195lb/ft if on SUL.backbox sounded good.
He liked it (had two Impreza turbos before this)
Had problems with premature wear on inner edge of all four tyres though (like EVO did).
Prodrive figure were o-60 6.9 and 30-70 7.5 secs.
problem was when he sold it the 4k pack added little to the trade in value (ouch!)

MattRus

Any ideas what the differences are between a Forester STurbo motor and an Impreza Turbo.
I am guessing, ECU differences, and valve lift / timing (different cams?). Everything else seems to be the same. Wonder if I can swap the ECU for an Impreza one?

Butty

iTrader: (2)

Matt,
the rear bar swap required larger bushes off an Imprezza (Ģ7-00 each). The rear links were sourced direct from Suabru (a friendly dealer for a change) but cost a wopping Ģ200 all round.

The bar came from Midland Imprezza (024 7637 3555) for Ģ30-00 s/hand. I specced the 18mm size but seemed to end up with 19/20mm by the look of it.No idea what model it has come off as I thought there was only two sizes
You could go for the 21mm which comes off the old WRX STi grey imports.
Job only took 1/2 hr but undoing had to be in right order as bar is slightly different shape from Forester and difficult to hook over rear box.

Nick

Jamie Whitfield

Matt

I reckon the next step after the Hayward & Scott BB being fitted, should be to improve the breathing of your car further, if we look at the induction side of things we should be able to come up with something.

Also if you could keep me posted on how the Dawes goes on the Forrester that would be great!

Jamie

www.performanceexhausts.net

MattRus

I will be doing this very soon Jamie. I already have a K&N panel fitted though and hope to fit a cool air induction kit.
Incidentally, no deliveries yet, any ideas?

Jamie Whitfield

I'll double check in the morning, I was told it had been sent out a week ago!

MattRus

Dawes now fitted!
I have been monitoring boost for the last week without the Dawes and was getting the following (with the usual spikes).
rpm boost (PSI)
2000 5.5
2500 6.5
3000 6.5
3500 7.5
4000 8.0
4500 8.5
5500 8.5
6000 8.5

All maximums in 4th/5th (spiked too 9.7).
As can be seen this is somewhat less than an Impreza.
With Dawes I now get consistently 4 PSI higher at most rpm sites with little or no spiking. This is after initial setup.
The motor is a great deal more urgent from lower rpm now.
Downside is some part throttle hesitation. AFR is the usual very safe high value still though.
I think ECU mod's maybe the best way to go but I will continue some further experiments with the Dawes.
Verdict, so very good value for money!
Watch this space.

Brian 1947

Butty,
Read your comments with great interest as I have recently imported a Forester T/tb. At the moment it is in standard spec but I hope to fit an induction kit and back box. My only gripe is that the power steering is so heavily assisted compared to my old Legacy and so lacks feedback. Is the S/tb similar ?
Brian

MattRus

Hi Brian,

unfortunately yes! Fitting 17" wheels and 215/50 tyres helps to give more feel and immense grip. Enjoy what is a unique vehicle.

Matt

Butty

iTrader: (2)

Hi Brian,
Your not a million miles away from me (about 25 miles to the North of me I think). Is yours red with a personal plate ACH ** I saw near Northampton two weeks ago?
E-mail me on nick@buttn.freeserve.co.uk if you fancy a meet?

I have always found the steering very light (also clutch). I guess that the Legacy had 15/16" wheels with narrower width so the TTB may feel heavier.

Matt, what info did you give Jamie to get the right kit for the Dawes? My STB is currently running a constant 0.75 bar (11 psi) all through the range so I guess the hole size has to change??

Nick

MattRus

Hi Nick,

Dawes race 'kit' was supplied with a 1.5mm hole already drilled, so I can't comment on using a smaller bleed. Further adjustments today resulted in a more constant 10 - 11 psi between 2000 - 5000 rpm.
Stretched the spring a little to move the adjustment the middle.
I set the device using an accurate pressure gauge, a regulator and compressed air. I have set it to open at 13PSI to see how that effects peak boost. I don't seem to be able to get more than 13.5 PSI peak though! Will probably set the valve to open at 12PSI for safety.
Any ideas on other sensible mods. I can do to get some better throttle response& mid/top range power?

Butty

iTrader: (2)

Hi Matt,
sounds like you now have the boost of a std UK Imprezza turbo?
It would be interesting to see it on a rolling road. If output is also as per Imprezza then perhaps only diffrenece is ECU control of boost, rather than turbo internals and cam shaft.

I suppose the route now is to follow normal Imprezza methods for power increases.

On other fronts, there are strut braces (front & back) and perhaps bigger brake size. I have looked at Godspeed kits to go to either 305 or 335 mm under 17" wheels - but not until the current discs have worn.
Can't really think of anything else (did you say that you have lowered suspension) that is relatively cheap.

Nick

Toerag

Allegedly the S-turbo has a smaller turbo than the impreza and a different ECU. So swop the 2 and you'll be playing with the big boys!

Forester_GP

Boy, how did i miss this thread ? Well... i went down the Ecutek route and the car flies now. My specs are : 248.5 hp @ 5921 and 248 lbf @ very flat torque curve at only 11.5-11.7 PSI which are hit by 2300xRPM. Other engine mods include; GGR sports cat full exhaust, samco turbo & intercooler pipes and Impreza MY'00 dump valve. David (Ecutek) has my latest maps should anybody need to run similar tunes to his car. I also have dyno runs and DD logs (countless) and i'll try to post them if you ask me for it. I don't have 0-60 runs but somerwhere earlier in the posts that 7.5 secs seemed awfully slow to me just by looking at my DD runs.

Regards,

George

Butty

iTrader: (2)

Mmm... sounds nice. Have you any piccies?
I guess you should be hitting low 6 sec sprints to 60 mph with that power as it is the same as a JDM Forester.
Why not post you RR output on the Scoobynet page?

Nick

[Edited by Butty - 11/28/2002 9:10:57 PM]

Forester_GP

This run only produced 10.7 PSI at the dyno and at a latter RPM as the operator was advancing the pedal very pregressively. Restrictor size was 1.1mm and not the 1.0mm as i usually run. Ambient was 26 C and max air intake around 44 C

regards,

George
P.S.I hope i got it right. Many thanks to Wrexy for instructions.

MattRus

Looks like you have the map ECUtek developed on my Forester MY00.
The other mods are more or less identical to the ones on my car.
I have now covered 20,000miles with the mods and no real problems.
With higher ambient temperature (over 32 deg. C inlet temp) the ECU will retard the ignition for knock protection, this soon resets though. However in Englands cool, damp climate (most of the year!) it goes like hell! Fuel consumption under 'normal' driving conditions also improved by about 5mpg. A very worthwhile modification.

Toerag

Cost for the mods? Are you still with the original turbo, and do you find it gets too hot? I've had my standard turbo glowing on a couple of occasions!

Forester_GP

Matt, yes we started off with your map but we latter modded further (TEK3 really)on my original ECU by raising boost target to 11.5 PSI, Wastegate solenoid duty to 75 % and some +/- fuel at various regions. I currently run at constant 11.6-11.8 from 2300 up to 5800 and then it tapers off to 10.2 @6400. No detting now, even when at 34C during summer, i would only get up to -1.5 retard during ECU's learning cycle. Now, @ 16C - 22C ambient i get No det as max intake (post cooler) rises to 44 C (long blasts) and 35 C during short WOT runs. A VERY worthwhile Mod.

Toerag, I thing the turbo is sufficient at above boost levels,and dont care if it glows red as long as the intake temps stay at these levels. Total costs around 700 GBP for the ECU (programming + DeltaDash and 4 shipments back & forth) plus 1200 GBP for Exhaust + Samco hoses.

Regards,

George

Plipton

Butty Said; "If output is also as per Imprezza then perhaps only diffrenece is ECU control of boost, rather than turbo internals and cam shaft."

I read the guff from Dawes - my understanding is the Dawes over-rides the ECU on boost control. Am I mistaken ?

If this is the case then your boost is limited elsewhere.

MattRus

Turbo internals are different, so is the wastegate. I have seen 21psi using the standard Forester turbo and a Dawes device for a short while, so it can produce the pressure but not for a sustained period. The standard Forester has a 'bypassed' dump valve that bleeds away excess boost (I think this 'softens' the valves action for more subtle action). With this fitted it is very difficult to get sustained boost above 12psi. Hence the reason we fitted the standard valve from an Impreza (STi in my case). The whole standard Forester engine control 'package' is designed for gentle, smooth, low down torque engine characteristic. The ECU whilst similar in operation, is not interchangable with an Impreza item, it can however be programmed the same way, hence the excellent ECUtek results. It is my feeling that the cam profiles maybe slightly different if not the cam timing. Engine internals an ancillaries (apart from those mentioned) are all the same.
A modified Forester (as shown in the other post's) is very similar in performance to a new Impreza WRX, with the benefit that the torque is superior lower down! Wheel and brake modifications are required before these modifications are made though (IMHO).

EMS

MattRus,

Itīs possible to make the dumpvalve "work" like an Impreza one. You only have to disconnect the rear (near to the intercooler) hose and close that hose. (The Forester with automatic gearbox uses the Impreza dump valve)

I donīt think they used different cams in the Forester. (expensive!) Your right about the turbo and the ECU.

Mark.

EMS

Look out for too much boost with std. ECU on the Forester!!! (10 PSI is about the maximum)

The mixture can become very lean and there is a lot of advance programmed in the ECU. It doesnīt suit high boost.

Go for a proper remap, the car will run much better and is far more reliable!

Mark.

Butty

iTrader: (2)

Hi Kruel,
Tuning the old shaped Forester never got going in the UK and you'd probably be one of the first to do anything for the new shape.
The best bet for US tuning help is on http://forums.nasioc.com/forums/forumdisplay.php?s=&forumid=36

or an Aussie slant http://www.subaruforester.com/forum/index.php

Seems like the US have a 2.5 litre turbo version that is wooping the Imprezas a$$ out there.

Nick
1997 Forester S/tb

[Edited by Butty - 8/2/2003 9:34:14 PM]