ScoobyNet.com - Subaru Enthusiast Forum - Ns04's next round of mods: A forged build from APi

Hi all,

Recently got my 07 Sti back and run in after a forged build based around the SC46 turbo from the guys at APi. This thread will be of interest to anyone contemplating a big (ish) power build on their scooby!

Background and car details:

Some of you might know that my previous car was a VF35 based 340bhp Classic. It was a real low mileage minter that had been cherished and owned for 6 years by moi. Unfortunately, this car was written off in a very mundane and very low speed accident that occurred last August :cry:

Understandably, I was gutted, but one has to look for the good in these situations. For some time I was contemplating having a big power conversion done to the scooby, and this would have entailed more expense in an 11 year old classic than in a new age car. Sad though the loss was, this was the chance to find and create something special!

After a nightmare of a time getting the insurance folks to pay the money they'd promised, I had a stroke of luck. A low mileage 07 Hawkeye STi became available in Motherwell with all the PPP goodies: engine performance upgrade, PPF7s, lowered springs, mudflaps, front splitter etc... A stunning car....even more so because of it's colour: solid white! I had to have it. :luvlove:

Driving home from Scotland, I contemplated my options. I had spent no small sum of money on a great car that went very nicely. Do I call it quits at that, or invest even more money in turning this car into a bit of a beast! Hmmm, this was going to require some careful thought! :wonder: ........

On the way back home, I popped into APi to get the car's oil changed and 3 mins later had decided that I simply HAD to have a big bhp rebuild! :D Actually, to be honest, David and I had been discussing options for some time. The following day, I took the car to Bob Rawle to remap the car on the PPP hardware for the interim. As always, he performed wonders and I left with 348bhp and 380ft lbs torque. That's about as much as you're going to get reliably on the Hawk with the standard turbo. Unfortunately, the pistons on Hawks won't take more than 1.35 bar boost before you're going to run into the dreaded ring land failure. 1.35..... Pah, my old classic took 1.5bar of boost on std pistons, this would not stand. Time for a forged rebuild!!! :D

So, what was I after? Simple really. I wanted to retain that lovely low down torque that the 2.5 engine provides, but give it a turbo that could make use of the engine capacity and provide a properly ballistic car for the road. It had to have excellent spool characteristics, it should deliver 450bhp and 450lbs ft torque or above and it HAD to be 100% reliable. I really couldn’t emphasise the last part strongly enough. I’m not loaded: I can’t afford to have something spectacular, but with no longevity, or a perpetual project that spends most of it’s time on the ramps or needs constant fiddling. It had to be a "drive in and drive out" solution as far as possible!

So, who did I give the car to for the rebuild?

Well, no surprise – it had to be David and the lads at APi. However, this isn’t just idle favouritism by me; the reason it went to APi is that they did the work on my classic and it delivered as promised. Whenever David has given me advice, it has invariably been sound. More importantly, when I needed help dealing with the aftermath of the accident in the old car, David was right there lending his experience and help arranging storage, getting repair quotes, etc… This is just one example of APi’s commitment to customer service and this kind of thing is very salient when you’re contemplating spending a 5 figure sum on a car: You NEED a company who will a) do the job right b) provide the right level of customer care afterward! As I’ve said, this was, financially speaking, a big deal for me. It was an indulgence, of course it was, but be that as it may I couldn’t afford to put this much money into a car that wouldn’t deliver or would end up costing twice as much as anticipated to complete. I also wouldn’t have wanted a build where I had to worry about whether it could handle the power reliably. David et al got the car, because they had proved themselves on numerous occasions to be knowledgeable, reliable and trustworthy!

So, what specification was the car built to?

David and I agreed the following specification - I didn’t want to try anything experimental; I wanted a specification that would just work.

Engine specification
STi 9 EJ257 2.5 engine
- Supertech forged pistons
- APi steel rods
- Cosworth 11mm head stud kit
- ACL bearings
- Cosworth gaskets and seals
- Tufnol inlet spacers
- Cosworth baffled sump
Ancillaries and supporting modifications
- SC46 Billet turbo
- Mongoose 3 inch exhaust.
- Gen 2 Spec tubular headers
- APi variable flow injectors
- Fuel Lab fuel pressure regulator
- APi parallel fuel rail conversion
- RCM fuel pump
- APi oil pump
- Mocal oil cooler kit
- Hybrid FMIC
- Simota inner wing cold air induction kit
- 3 port boost solenoid
- Perrin turbo inlet hose
Drivetrain modifications
- AP organic clutch
- APi Lightened flywheel

The car was left at APi over Xmas, and I was kindly lent the APi courtesy car: a 2.0 Impreza sport, subsequently named “The Passion Wagon” by moi…… on the basis that it smelled a bit…..let’s say musky! :eek::Suspiciou :D I’ll be honest, the performance was something of a disappointment having come from a 350bhp Impreza, but If I’m honest…….and keep this to yourselves….. I quite liked that old car! It was even run on SUL -possibly for the first time in its entire life- whilst I had it! I joked to my mate that when I returned it to APi it will probably try and follow me home! Lol

February comes and Collection day arrives!

Jumped in the passion wagon and drove to APi to be greeted by a quite stressed looking David who announced that they were having the devils own job getting the Hybrid intercooler to fit. It transpired that great though the hybrid is, there isn’t (or wasn’t) a kit that fitted the hawk without an awful lot of fiddling! Doh! Anyway, long story short, it turned out that Bob and I had to put the running in map on the car without a front bumper attached…. We did get a few strange looks driving around :D Anyway, upon returning it was obvious that the car wasn’t going to be ready for the end of that day, so I had to go home in the passion wagon, feeling a bit dejected that I didn’t have my car back then and there. Still I did remember David telling me from the outset that in a project of this size, sometimes unexpected snags occur and this is something that everyone contemplating a big bhp build needs to bare in mind: even the experts get caught out occasionally and need longer than anticipated to scratch their heads in order to make something work.

Fast forward a week and I’m back again to pick the car up to run in! Anyone who’s had to run a high power engine in will understand the frustration that this entails. 4k rpm limit, easy on the boost, try and show the car a variety of engine speeds and loads for the first 1000 miles and then come back for an oil change. 1000 miles of knowing what the car was going to be capable of and having to drive it gently…… think of it a performance car foreplay that goes on…..and on….and on……and on… lol

Fast forward 1200 miles….it’s remap time!!

Off to Api for the oil and plugs to be changed and the over to Bob’s to have the proper map installed. Initially, the session went perfectly normally, until any more than 1bar of boost was attempted, whereupon the car lost all power. “Don’t lift off” said Bob. “I’m not” I replied, “I just hear this noise like the doors on Star Trek closing and the car loses all boost!”. For once, my dodgy driving wasn’t to blame: when bob looked under the bonnet, it was obvious that the RCM intake pipe originally specified for the car was way too soft and was literally being sucked shut when any appreciable boost was going through it. Game over for that mapping session! I was very disappointed – this meant another trip to APi to replace the hose and then back to Bob for the remap to be done again! There was some consolation in that Bob commented that the turbo was spooling like an SC38 and that it was shaping up to be a very nice road car!

Fast forward another two weeks and it’s back to APi to have a Perrin intake hose connected and then off again to Bob for a second stab at the remap! This time, it went smoothly, after an initial scare involving a lazy lambda sensor, which temporarily decided to go on strike! I was immediately impressed by the grunt of the motor in the higher gears and just how responsive it was. Bob installed the RaceRom features and we did a deltadyno run or 4! (graph at the end of this piece). I declined the opportunity to test out the launch control and flat foot shifting, as I was too much of a wuss to risk hurting my new acquisition…..or , more likely, embarrassing myself with inept attempts to really give the car some stick! :D

The drive home

Brought back memories of when I had my classic mapped: the joys of the M4. 5th Gear down the slip road, I spotted a gap in the traffic, foot down……..WHOAAAAAAAAAAAAAAA! Traffic behind me reduced to a distant memory, traffic in front now filling the windscreen (thankful for the 6 pot APs at this point). Time to move out to the fast lane: foot down again and I remember thinking “Damn, I’ve already changed up to 6th” Then I noticed, in the time it took me to think those words, I already sailed past the traffic in the middle lane. Oh, and, by the way, the last two runs had been about 50% throttle! This car is now seriously quick on the motorways, it streaks past slower traffic with a brush of the throttle. Above 2000 rpm 6th gear still gives you all the punch you’d ever need to get past dawdling traffic. 5th makes you shoot past them at a fairly indecent rate and 4th is just plain showing off!! :D

I should stress that it’s still early days and I’m still getting to know the car, but I'll give you my initial impressions based on my exposure so far.

Performance:

Now, it’s probably worth reiterating at this point that I’m not exactly a newbie to turbocharged Imprezas. My old MY99 had 340/340 and any of you who have a similarly endowed classic know that it makes for a very quick road car. If it’s equipped with a VF34/35 it’s also very responsive with a nice low boost threshold and very good spool characteristics. In short, the new car had its work cut out to become a demonstrably quicker point to point machine. So, was my money well spent?

Let me put it this way: the spool characteristics of the car remind me of my classic when it had the little TD04 fitted and yet this is a 460bhp turbo!! It really is remarkable. Compared to the car when it was remapped with the PPP set up, this is just a league ahead in terms of the performance. Whereas the original car had nice low down grunt, but got a bit breathless over 4k, this one retains all of the low down meatiness and then some, but give the turbo the nod and it just hurls you down the road with increasing vigor. The pace of this car down a good road is scarcely believable it just devours any straights and then exhibits typical Scooby grip and tenacity in the bends. Need to overtake, well a surplus of torque makes short work of any traffic you need to get past: on NSL roads, you can make great progress with 5th gear, such is the low down torque. Put it into 4th and you just slingshot from bend to bend and 3rd is just for showing off! If you take it for a sprint through the gears, the rate at which this car gets through them is just daft 1-4 is just a blur (and this is a long legged UK geared car don’t forget). Make no mistake; this is still performance that you can use: full throttle in first? If it’s dry, not a problem, sir! It’s also still at a level where the power isn’t too much for the chassis (although I’m glad I have APs on the car!!). What’s perhaps most impressive about this conversion though is its flexibility – it just has power everywhere and is so tractable: 40mph, 5th gear, foot down and off it goes: no complaint, just an increasing surge of power. It’s easy when you want to cruise around town, it’s fast when you’re just making progress and it’s really, really fast when you are in the mood for a bit of fun. :D Most owners of Japanese performance cars are a bit spoiled for bhp and torque and probably take such figures for granted, or are just desensitised to them. However it’s worth putting the power of a SC46 Scooby in context: what we’re talking here is a power to weight ratio equal to or greater than a Porsche 911 turbo. What we’re talking about here is a torque to weight ratio significantly greater than some Ferraris, Porsches, Aston Martins, BMWs, Mercs. Be in no doubt: a Scooby/Evo at this level is a serious piece of kit!

Drivability

When you get a 460bhp turbo on a car, you expect it to be fast: that’s obvious. However, it wasn’t so long ago that having this kind of output would mean enduring a car with old school turbo delivery: foot down, wait for it……….wait for it….. BANG. No such concerns with the 2.5 engine and a billet turbo. It pulls from nothing and just keeps going! Bob and I did a test to assess where the car made 1.0 bar of boost in 4th gear and it did it at 2700rpm and the full 1.75 bar very shortly thereafter. It has 400ft lbs or above torque between 3.2k and 6k with its peak torque at 4k rpm. Even at 2.5k revs it’s producing about 280 ft lbs. Driving around town it’s a complete pussycat: you can just put it in a high gear and use the torque to scoot around. On the motorways it’s effortless, on A&B roads you never feel like you have to gun it to make progress, you can stay perfectly within the speed limits and still put a smile on your face, because that lovely turbo surge is but a small flex of the ankle away.

Refinement.

First things first, most people will tell you that forged engines are noisy when cold! Someone on SN once memorably described theirs as sounding like a "skeleton wa*king in a biscuit barrel" when cold! Well, they should have had Supertech pistons fitted. I can honestly say that if they are noisier when cold than the standard pistons, I haven’t noticed!! The car just sounds like a scooby with non-forged engine!

I admit, I’m really not one for loud exhausts! I like the scooby rumble as much as the next person, but I want to be able to converse with passengers and not fall out with the neighbours! I was also enjoying the added refinement of the new age over the loud and comparatively crude classic! The mongoose system on the car is very good in this respect. It still gives you a nice rumble at tick-over and low speed, but when you put your foot down, well….I guess there isn’t an exhaust system out there that’ll keep the car’s potential under wraps then, is there? My only complaint is that the tailpipe does not stand proud from the bumper, so all the soot from the exhaust gets deposited straight up the bumper of my lovely white car! D’Oh!! It’s a complete bitch to get off too!! Anyone know of a anything I can put around that part of the bumper to protect it? I also suspect that if the exhaust tailpipe stood more proud of the bumper there would be even less noise in the cabin.

Economy

Well, we can talk about that, or we can be happy! :D

Get to the figures!!!!

Ok, ok!! here's the thing you've all been waiting for.....cause I know how SN likes its power graphs and numbers. I'm usually much more interested in how the car feels "the bum dyno" than figures per se, but I'll admit it was good to have some for the car to quantify the gains after the conversion.

http://img.photobucket.com/albums/v6...Powergraph.jpg

Concluding comments and acknowledgments/thanks

A massive thanks to David, Nathan and the other lads at APi who worked on the car. There were a few hiccups along the way, but once again, they produced something which did exactly what it said on the tin. More importantly, David was always there to provide advice and reassurance….. important when one is spending a big sum of money on their car! Also, a big thanks to Bob at BRD for his advice and usual sterling job mapping the car.

If you’re planning to have a big bhp conversion, I can wholeheartedly recommend both companies!

I'd also like to extend special thanks to Gary Moulson for being a great insurance broker who helped me out a great deal during a rough time! :thumb: Oh, and got me a really good quote on the above beast! :thumb: If you want to get a competitive quote for your high power scooby, you could do a lot worse than give Keith Michaels s a call and ask to speak to Gary!

Hope the above has been of some interest to you! I'll leave you with a shot of the car!

http://img.photobucket.com/albums/v683/ns04/Phantom.jpg

Ns04