Hi all, im looking into getting another classic impreza as a weekend toy. previously had a classic 340hp and an evo 5 370hp. didn't really gel well with the evo, the second I had it I missed the impreza and the impreza was more reliable from my experience.


Now I have a house and a baby, so don't want to go too mad down the tuning route and another uk turbo 2000 seems to fit the bill although it may take a while to find a bone stock one with low miles and good service history lol.


This time I want to look at a car with excellent response, I tuned my old impreza on a td05 and the usual supporting mods, but want this time to keep the stock td04, which already has great response and make that even better! as I mostly drive round town etc and need response more then all out power.


So from experience guys, what items are proven to work to make the response and power better on the stock uk turbo with the tdo4.


Id be happy with a solid 260-290hp (I know numbers count for nothing really as ive said im more interested in the way it drives ) and things I want to discuss are....


headers... standard ported with a trick Harvey up-pipe? up-pipe size? heat wrapped?
Down pipe... wide mouth entry and bore size, heat wrapped also?exhaust... bore size and design?


I was thinking just a new age sti topmount for intercooler or is this overkill and a v5/6top mount fine??


Walbrough 255 pump, a decent panel filter (maybe a cosworth one again) with cold air feed to box and the ecutek remap once the parts are chosen and fitted.


Ok so what do you guys think, and what have you experienced, and is there much to be gained where response and power is concerned on the stock 04 turbo. many thanks. aaron.

 

the mapping is the costly thing on most Classics

 

From experience with my own 1997 UK Turbo enabling the ECU to be remapped meant having to install an ESL board to the existing ECU. See www.enduringsolutions.com for better info. The creator of it, Andy Stevens, is a member here too. I got around 270/280bhp from the stock TD04 and some seriously quick spool. I have a Blitz Nur Spec R full system and decat up and downpipes. Decatting alone will liberate quite a bit of power, some will argue that the car will need mapped for decatting though. Honestly if could do it all again I'd go for a JDM Classic which already has the higher power as standard and more importantly little or no rust that's associated with Classics that have resided in the UK for years.

 

Your horsepower figures are classic WRX/ STI territory... Instead of tuning a TD04, have you considered a standard TD05 on an import and leaving it pretty much stock?
The driving experience is different with the TD05, I'll admit, but I can't help thinking that the money that you'll save in the long run will be worth it. All the stuff that you've mentioned will not be needed and you won't need a remap, because the car will already have the performance that you're after...
I know it's down to personal preference, just wanted to offer an alternative.

 

Have a word with Alyn at AS Performance for advice on headers and the Harvey up-pipe.

My own, a Harvey built 2.5 forged unit, is giving 1 bar at 2500 rpm. That's with a Harvey tweaked TD05 20g.

 

My plans are ultimately to have a hybrid billet TD04 for the reasons you mentioned, I'm not into top end and silly speeds or big numbers, I think it's a bit over rated and expensive

They say the Harvey up pipe is good for spool and responsiveness, I have ported an STI up pipe and a spare TD04 I had in the garage and am planning on fitting those along with an AP clutch and an Exeddy light weight flywheel which is again good for responsiveness (I had it in my Type R) and it did help the pick up, takes a bit of getting used to (slightly higher revs to pull off) but you might want to consider adding one to your list.

I'll be wrapping everything from the headers to the down pipe and fitting a turbo blanket too, as this is said to aid spool and keeps the engine bay temps down, I'll also port the headers.

I had a divorced waste gate down pipe on my Type R and can't say I noticed any difference, but I'll be going with a prodrive sports cat down pipe this time to avoid hassle come mot time.

I'll do that lot then decide if I'm going to send off the TD04 for the conversion.

 

Thanks for the info guys some good food for thought. Actually managed to find what looks like a decent one and dropped a deposit on it. Its an x reg with 80k full stamped history all old mots etc. excellent example and already has the few normal goodies to set me in the right direction.

Mate, great info in here thanks! After more reading around too, this is what im leaning towards... What do you think....

Ported oem headers wrapped, harvey trick up.pipe already wrapped (the bore size i will discuss with supplier)
There is a full exhaust on there which i will leave as its a straight through decat but i will wrap the d.pipe for good measure.
I am now leaning towards a turbo change, but still a td04. Ive seen the andy forrest one on his site, still has the same spool characteristics but will get me to 300-320hp...more then enough for me! Are there any alternatives that may achieve even better spool that you know of?
Intercooler ill put on a v5/6 top mount with samcos to keep core size down, flow rate up and the cooling will be adequate as i had a v6 top mount on my old impreza running 340hp. It has a bailey bov on i will prob return back to standard re circ.
Clutch and flywheel are a great point that i overlooked, which is defo something to get done when i need a new clutch sooner or later! Cheers.
Its already a non air con model so one less pulley, but maybe swap out the 3 pulleys for lightweight billet ones.
Induction it already has a blitz so sorted there too.

The car already has an ecutek map on it and i estimate probably around 260hp as its only really got the pump,exhaust and filter, the intercooler is still the stock black one. But to be honest it feels great in first and second, way better then my old one was, so excited to see results from the further mentioned mods and the extra 40-50 horse. Probably get all my parts bought ready and drop it all down for fitting and mapping at pole position like i did with the old one. Cheers guys, aaron.

 

Sounds like a plan, you may need to change your injectors to JDM 440 side feeds as I'm not sure what came with the uk cars as they could hold you back if your heading for 300+bhp I have run them to 330bhp on my STI Type R, so you may want to stick up a thread in the wanted section.

And yes lose the dump valve and fit a standard re-circ.

 

P.S I don't think there is anything that spools faster than a Hybrid Billet TD04 and they're not too expensive either, I think scooby clinic do one for around £500 exchange, Andy Forest doesn't do them anymore.

 

Ill look into that turbo then great stuff mate and priced good too! My last one i bought stock and im sure the v6 uk t2000 comes with 440 yellows. My last one did anyway. Easy enough to check though and ad to the list if need be. Thanks mate.