I know I've said in my other thread that I'm concentrating on handling on my next UK Impreza.. but once that is done, I'll want to boost the 215bhp slightly.

My aim is to have around 285-295bhp with 310-320ft/lb.

Some of the mods below might not be possible to fit, or might not be needed.. although I'll be trying to build a strong, unstressed engine rather than running things at the limit. Which, in my experience, ends in a bang, some smoke and a big bill.

Full 3" De-Cat System
(Wrapped) Gruppe-S Headers & Up-pipe
Green Panel Filter
Walboro 255l/hr
Sard FPR
Hybrid FMIC
VF34 (STi8) Turbo
Andy-F Tek 3
Exedy Clutch & Lightened Flywheel

Do you think that I would reach my power goals with the above spec, have I considerably 'over-specced' any bits of it??

I want a car that will be responsive with a large mid-range shove rather than a high revving, high bhp 2.0L motor..

Will the gearbox be ok running that level of torque??


Cheers,
Grant

 

I'd say you should acheive those goals with that spec. You should consult your mapper though.

Personally I think the FMIC is unncecessary, unless you're going to track the car extensively, or you like sustained high speed runs. I'd also be inclined to just port the OEM headers at those power levels.
You should also consider a sports cat DP, as if you fully decat, the car won't be road legal and you'll get hassle at MOT time. There is an excellent one available for the classic scooby from Scoobyworld much cheaper than you might think too!

You should budget for an uprated gearbox if you intend going above 300 ft lbs of torque. Some boxes hold up, others don't, even when driven sympathetically. You don't want a car you've spent a small fortune on upgrading only to be sat on the drive needed a couple of grands worth of gearbox work.

Oh, you should also budget for a knocklink, oil temp, pressure and boost guages and a pod to house them.

 

Thanks for the reply New Scooby...

The aim of the car is to be very driveable on the road, with the torque to make progress cleanly.. I do like the occasional high speed drive and I will be taking the car on track, possibly 5 or 6 times a year on average.

I was thinking that the stock UK intercooler was probably not up to the job, or at least on its limits, and the fact you can pick up a Hybrid FMIC Kit for c400pounds now.. seems silly to start chopping around to fit an STi V4,5,6 TMIC. Also, this would also allow me to realise a dream and fit a Sport bonnet to go for the ultra stealth look.....

Forgot to say that there will be supporting mods done before I think about increasing performance.. Gauges, K'Link, A/F Display, SECS Data Monitor.

Regarding the De-Cat System......... the local place carries a Full Standard Impreza System (both CATS) for exactly that reason.. they fit it, MOT the car and then re-fit the Stainless System for you.

How much would an uprated gearbox be for a UK Turbo?? I've seen 6-Speed STi G'boxes for about 1500 2nd hand, but they require a diff as well.. How much would it be for a full 6-Speed Set-Up??


Cheers,
Grant

 

I agree that if you're going to upgrade the IC (and your mapper is probably the best person to advise on this) you may as well do it properly and get the hybrid FMIC, they are very competitively priced.

It's good to have a friendly MOT station but the problem is, if you run a full decat your car isn't road legal and this may have implications should you need to claim off the insurance etc.. My Ninja 100 cel DP cost £299 (about 100 quid more (or 4 CAT pipe MOT fudges) than a good Decat DP and it means that the car is fully road legal.

Regarding the gearbox, you're best off consulting David at API, an expert in Scooby engine and transmission rebuilds. He does exchanges etc... so I guess the price depends on the extent of the damage to yours and what you want etc.. I think you'd be looking at 2k for a 6 speeder. Many seem to reccommend an uprated 5 speeder from PPG IIRC, supposed to be bullet proof (about 2.5k).

Ns04

 

Not necessarily a good idea! The scoop is primarily there for the intercooler but if you look at it you'll see it also diverts some of the air towards the turbo to aid it's cooling. Getting rid of it may have serious effects on the under bonnet temps.

 

A good approach If you're are after those figures then I think a 2.5inch exhaust will do as will ported headers. Andy can advise though as he'll be mapping by the looks of it.

F

 

Ns04.. I see what you're saying about the De-Cat issue, I'll look into the Ninja 100 CEL when I'm buying the parts for the car. I see your point that it'll only take a handful of 'trips' to the garage to cover the extra cost over a De-Cat D/Pipe....

Have seen a few big power cars that run the PPG 5-Speed, so think that at my levels, it should genuinely be bulletproof.. haha, famous last words!? I hope not!!

Graz, I understand what you're saying about underbonnet temps.. I hadnt considered that before to be honest, I just assumed that it wouldnt be a problem. I will definitely look into this closer to the time and try to get feedback from people that have used the Sport Bonnet on turbo'd Imprezas.

Thanks Floyd, I wasnt sure about the 2.5" or 3" exhaust, but I thought that if I did want to upgrade in the future then it would be nice to find that the exhaust wasnt a restriction. I'm not sure about Ported Headers, I've not been able to find any tests that prove they work.. specific before and after porting R/R Readouts etc, I'm a little sceptical, but very willing to be proved wrong!!

I followed your Project Thread with interest.. Was a great read with lots of useful info!!


Cheers,
Grant

 

IIRC Autospeed did a back top back test with std/ported headers and afetr market headers. The conclusion was that the best ideal headers would be made of cast iron for heat retention and early spool characteristics but stainless tube for top end flow! The ported headers weren't that far behind the SS headers.

F

 

I'm running ported OE headers Grant and I'm at 345bhp & 325 lb/ft FWIW. Much earlier spool up then my old semi-unequal length efforts.

 

Who would be able to port my OE headers and any idea of the cost.

Cheers

 

David at APi

Harvey on here are the two that spring to mind.

Ns04

 

Approx £120-150

Andy

 

Thanks for the info guys... as I'm looking for a responsive drive so the early spool of Ported OE Headers is pretty appealing to me, I hear what you are saying about aftermarket ones boosting top end power and thats not what I'm after really.

Just so happens I've got a set of standard 15k mile efforts lying in the garage gathering dust, might give this Porting stuff a bash myself....... or be sensible, and pay someone that knows what they are doing to do it for me.

Thanks again for all the replies, glad to know that the spec I listed wasnt tooooooo far off the mark for the goals I'm aiming for!!


Cheers,
Grant