hi all,

have been wondering about this for a bit and thought someone round here would probably be able to enlighten me:

as i understand it ( from what i've been told ) the JDM classic wagon has a smaller turbo than the uk one. if this is the case then where does the extra 10/12 bhp come from? ( since it is supposedly 220/218bhp)

how does this mean the performance relates in comparison of the two modles? since the gearing is suppoesedly different too, does one have more torque/speed?

and finally, would it be possible/advisable/benificial to put a larger uk turbo on the JDM?

cheers.

 

extra power from more aggressive mapping for 100 RON jap fuel I would imagine.

Performance wise I used to have a TD05 (larger turbo) equipped UK wagon which I had mapped to 15.5psi boost target using a cheapo scoobyecu (when they were available). I had a few runs with various jap/euro spec cars with the TD04 (smaller turbo) and once the initial lag was overcome my car was quicker by some margin.
if you went the TD05 route then you would need mapping to suit, the car would be quicker and you could use 98 RON fuel without octane booster.
Personally though unless it was cheap I wouldn't bother, you sacrifice everyday useability for the power increase IMHO.

 

JDM Classic 'Wagons do have a TD04 as fitted to later Classics, as opposed to a TD05 fitted to the saloons. This is principally to provide greater low down torque; on a JDM wagon torque peaks at about 3,500 RPM. The gearing on a JDM Impreza is lower; Ive found the acceleration on my JDM 'Wagon to be unmatched by (new) UK Scoobies; even STI's. This is a result of the lower gearing and the fat low down torqe and perhaps a little driving talent (and it weighs less!).

You can fit a TD05 to a JDB 'Wagon if you like; Id suggest getting a ScoobyECU to compliment it too; if you can find one. If you havent driven a 'Wagon Id wait until you have before you decide. Theyre quite different and I prefer them.

Simon

 

i bought a wagon recently (my95) JDM wrx 220bhp. since then have heard people saying about smaller turbos etc... was just wondering about the next possible steps to more increase the fun since am getting used to the power already.

the boost seems to come on well but is quite short lived. was curious if the small turbo was the explanation.

it sound like a lot of bother for a little gain will probably leave well alone.
cheers

 

The gain will be significant- if you can find a cheap scoobyecu it's worth it if you can live with the decreased practicality. You'll find the boost won't drop off quite as quickly, although I have no idea how well the smaller turbo cars respond to the remap. I seem to remember reading about some problems mapping these TD04 cars. Have a look on the SIDC for more info.
Be aware though the fuel tank on these cars is very small. Mine went from 260miles a tank down to 180 after the remap and back box/filter. It was quite a bit quicker though .
Also you won't have to run on octane booster+98 RON as is the case at the moment. Could save you a fiar bit of money in the long run.

 

at the mo i have an induction kit and 4" exhaust (still got the cat in and don't want to bother replacing it for each mot) any other relatively simple ways to squeeze a couple of extra horses out?

 

For a ScoobyECU you DEFINATELY need a TD05.

 

SIDC?

 

Your car has 2 cats, you could remove the one in the center pipe and still pass an emissions test.
Other than that perhaps you could try a dawes device? I have no experience of them myself but a quick look in the tech sections should point you in the right direction.

edited to add: SIDC= Subaru Impreza drivers club

www.sidc.co.uk

Like scoobynet but friendlier and with better advice/class of people!

 

Impreza's dont benefit from induction kits; you might be better replacing the OEM panel filter and saving your MAF and perhaps a lot more...

 

oh right, previous owner put on induction kit, what a waste of £200 then.

also, centre pipe cat is a gonner.

seems like i'm about set then.

 

TD05's don't suffer from that much lag. I had an indicated 1 bar boost @ 2850rpm at a mapping session yesterday with 1.25 bar (18.13psi) set as the max.


Edit: 1bar=14.5psi

 

Mine must have been fooked then. Upto 3K nothing at all, then *WHAM* a real kick as it took off all the way to the redline (after scoobyECU).
Old skool turbo lag at its worse in my car, bloody good fun though, as long as you didn't want to smoke people from the lights. Too many 4K starts=new clutch. I feel sorry for whoever ends up with my old car, it had a severe caning before I traded it in.

 

as far as i'm aware the boost setting is standard, how much can i tweek it without a remap or causing and probs?

 

ive got a 95 wrx wagon with induction kit and 4 1/2 inch exhaust with just 1 cat removed,theres terrible lag until 3000 revs then it kicks in and no noticeable power drop until 6500 revs,just had it on the rollin road,its got 232bhp with 234lb/ft and peak power was at 5600 revs,until i get a new clutch this is as far as itll go,
trekkker

 

I drive a JDM WRX Wagon (classic) with auto transmission, this car kicks ***.
Low down torque plus auto box = rapid car.
You can choose between manual gearchanges or auto changes...auto changes are very smooth and rapid. In manual mode, 70mph in second comes up very rapidly giving superb overtaking power.
4 inch rear box helps too.

Big-G

PS GC8 is top man for knowledge on these cars

 

The map in the JDM wagon trails the boost off at the top of the rev range, which is why it feels like its running out of puff.

To economically get more power you can fit a Dawes device or similar and set it to 1bar. Combine this with a full decat, boost gauge, AFR meter and Knocklink to monitor things. This should give you 250-260 bhp with early low down torque.

For everyday drivability, I prefer the td04 to the td05 as long as you know 270ish is probably the most you'll get out of a 90degree td04. If ultimately you want more power then the economical route would be a td05 and a ScoobyECU to get around 300 with out the need to change injectors, Map sensors etc.

hth

 

nice one guys,

will be quite happy with 260bhp without changing the turbo, the dawes option sounds like a good un.

where's the best place to start lookin for this ?

also any ideas to how much all fitted etc...