jdepould

iTrader: (2)

might want to put on your flame retardent jacket . . . the search button is your friend

Kevin M

iTrader: (12)

Actually it's not hard and it's not *that* expensive. I just wouldn't recommend until you tighten the nut behind the wheel enough to handle 500 horsepower.

se0ul

iTrader: (17)

wow baller..

meilers

And commit yourself to rebuilding that engine at least once a year (and the differentials, after you do your all-wheel-drive burnouts to impress your friends)...

jdepould

iTrader: (2)

if you tune it right and don't drive like an assclown it will be a lot more reliable

depdivr

Here you go, everyone else has blown you off - most likly because they don't know how to do it themselves. Ill be honest, I am running 323 WHP (about 400 at the flywheel) so I haven't hit the 400 WHP yet. I think I did things the right way so I will share my experiences from start to finish.

1) Cat Back Exhaust. Take your pick - I went with DC Sports. $600.00 - $1000
2) Air Intake (Cold air or Ram) - I went with cold air intake from AEM. $350.00

You will have no problem with these mods (except that they don't work worth a ****). Your new STI has one of the most advanced ECUs on the market today for a OEM car. It will sence a increase in air flow - you car will run a bit lean for about 40 to 80 miles giving you a false sence of HP. Sorry - the ECU is already working to back off on timing and increasing the mixture to prevent damage to your engine. Be thankful - it is way smarter than you are so this is not a bad thing. Unfortunatly, once the ECU learns - you will be at the same HP you started with or even less! Don't worry we can fix this...

All at the same time...
1) Turbo up-pipe - I went with PDE ($450.00)
2) Turbo down-pipe - I went with PDE ($300.00)
3) Stock ECU Reflash - I went with Ecutek ($800.00)
4) Hire an experienced tunner with a 4WD dyno ($250/hr)
5) Port and Pollish your turbo waste-gate ($300.00)

Here is the deal. The up and down pipe will eliminate all cats. Lot's of airflow! Your turbo will be seriously efficient and will have boost creep so your ECU will cut fuel and throw the CEL and flash your cruse control light. Bummer! Depending on your STI, you may also be running close to 80 to 100% of your injector duity cycle - again not good. We will go into this later. With out the Reflash, dyno tune and porting your wastegate, your stuck here. Before you even think about moving on - this must be done.

Ok, you are now a certified tunner looking for big horse power. Already you have graduated from the stock 230 WHP (300 at the flywheel) to about 270 to 280 depending on your tunners ability to get you to 80% of your injector duty cycle.

1) High flow fuel pump - I went with a Walbro 250 ($300.00)
2) 600 cc/min fuel injectors or higher - If you are really looking to go big go with injectors in the 800 cc range. I went with Perrin 860 cc/min injectors. ($700.00)
3) High flow fuel rail - I went with Perrin again, great package with stainless steel fuel lines included. ($600.00)

Don't do this mod at home. You will flood your cylinders in less than a block at be shooting flames out your exhaust like cops were shooting at the LA riots. This is extensive - unless you own the dyno, let your friendly tunner shop help you on this one.

Ok, you have the foundation. Your tunner just brought your stock turbo chargers boost from a stock 14.7 to 18 or 19. Your injectors are running at about 60% of their duity cycle and you are putting about 320 to 330 HP to the wheels and 400+ at the flywheel and your car is still reliable. Putting race gas into the tank and tunning for it may get you up to 350 WHP. Up to this point I can vouch for everthing... this is as far as I have gone.

Your bottleneck is now you turbo and the fundamental elements of you 2.5 L Engine. Throw in a new turbo to bring boost up to 25 or 28 and you will absolutly be at 400 WHP. Your injectors will handle it. Your engine may not. Your rings may pop, head may crack... I am honestly not sure how to push it further (I know it can be done) I just don't know how. Basically a engine rebuild is in order which is cool anyway so go for it.

Rather than shoot for 400, I really recomend keeping it at the 300 to 350 WHP range. After that, focus on your suspension - drop the car an inch or inch and a half and you will be cornering at faster speeds than your rich fathers 911 twin turbo - and you will blow him away with your speed (he will catch you on your top speed though).

I don't know if you noticed, I have not replaced the header - it will give you 4 or 5 HP but not more. Just didn't have the cost/HP justification for me.

Get the gagues. As you start to F around with your fuel system, you need the EGT (Exhaust gas temperature) gague, boost gague and air/fuel ratio gague. These may give you the split second information you need to keep your engine from a melt down.

Have fun!

PlatNmRex

iTrader: (9)

Very well said depdivr,
Although I don't think the subaru community would agree with you in general that one will be getting low 300's AWHP with stock turbo on 91 octane, I agree with most of what you said.

Jhuclimber,
I would visit, personally, a performance shop like Vishnu or Gruppe-S and ask them about what you need to do for your goal. There are alot of very safe and very strong tunes out there right now of STI's with GT30 turbo's who are making about 330-340AWHP on 91 octane. You should check this out. Just my 2Cents.

-Brian

Kevin M

iTrader: (12)

We know how to hit 400 whp on an STi. It's quite simple really. GT35 turbo (or equivalent), full 3" turboback, intake, injectors, fuel pump, FMIC, and engine management. That's it.

True, all full 3" catbacks are pretty much created equal, especially if they're attached to the stock downpipe. They're all the same, choose the look and sound you want. Intakes are not created equal- so far the Injen CAI seems to be the best in terms of matching the stock MAF readings and improving flow. Skip the short rams.

An STi does not need an aftermarket uppipe, it's already catless. And you shouldn't pay $450 for one anyway, even with installation. Make sure you choose a downpipe that has the same type of flange as your catback, or better yet just get a complete turboback in the first place.

'05s have not reported boost creep issues thus far. In fact, late '04s won't have issues either most of the time, because that's where IHI changed the VF39 from a smallish P17 exhaust housing to the P18 housing used on the VF30 and VF34. The wastegate port on that housing is sufficient. If you have an '04, you can get away without porting the wastegate if you have engine management and your tuner knows what he's doing, but I'd still recommend doing it. You'll also need a fuel pump here, as the stock injectors can't keep up with a stock turbo up top without one. Stock turbo STis routinely hit 100% DC or higher.

Uh... what?

You mean ability to reach Minimum Best Timing for max torque at a given RPM without knock. You don't tune to IDCs, you just make sure you're at or below 80%.

Okay seriously, you paid WAY too much for this stuff, even if it was installed. You picked good components though. Perrin injectors and rails seem to be universally liked, with good results from many tuners.

If you're getting reflashed, I agree, don't install the fuel components until you're at the tuner's shop, or tow your car there. If you have a Utec, AccessPort, or other PEMS, you should be able to get a good enough base map to drive slowly and conservatively there.

Um, I thought this was the part where you (unlike the rest of us) tell him how you got to 400 whp, like he was asking?

You must have missed Kingpin's 420 whp (on CA formulated 91 octane) GT35-powered STi, on a stock engine. Maybe it'll break soon, maybe not, but it can be done. Back in the day, some people insisted you couldn't put more than 320 hp through an EJ205, and how many people have made more than that at the wheels with it?

And "throw in a new turbo"? Which one? 25 or 28 psi? For a 400 whp turbo, that's probably a bit higher than it's peak efficiency. It's also more boost than the stock MAP sensor and boost solenoids can handle, so at this point you really should be running a standalone of some sort.

Wait... what? I thought you were going to do this:

Oops.

You need to know a lot more than where to adjust the ride height if you want to tackle a 911 turbo with an experienced driver. This is where my comment about the nut behind the wheel comes in. the STi is very capable of fast laptimes out of the box. If you can't come close to getting everything out of the car at the track, what's the point of modding suspension?

Good tubular headers appear to help the midrange on a stock turbo STi quite a bit. This indicates that with a larger turbo, they would show horsepower gains as well. Once you max out the turbo, other mods don't matter. In the midrange though, the turbo still has room, so the efficiency improvement from the headers translates to torque. In other words, headers are a good investment whether you have a stock turbo or not, as long as you don't mind the loss of most of that 'boxer' sound we all love.

Yes, get gauges. Boost and EGT are a must, people will differ about what order to get the rest in. I say fuel pressure next. A/F gauges are window dressing. They're absolutely useless for tuning, as they aren't fast enough, and how the HELL are you going to watch your AF gauge and your laptop to see what cell you're in on your fuel map to know where to adjust? You tune fuel with datalogs, not gauges.

If you can't have fun in an STi- any STi- check your pulse. But i agree, do whatever makes you happy with the car. That's how you justify the $32k price tag.

Lastly, depdivr, please don't take this post personally. It's not an attack on you. But when people post misinformation, and nobody corrects it, than other people read it and assume it's the gospel truth.

MARKSTI

iTrader: (4)

WOW...alota info, some good, some not.
I made about 365-370 on a DD DYNo thats about 420-425 on DYNO-jet.
On street gas the car made 310WHP on a DD,,,about 345 on Dyno-jet.

Gettin 400 whp is as hard as some would think,
Nice big turbo,good gas, and a decent tuner.,,Heres my parts list...

FP green turbo..great turbo for up to 400 WHP..not good for much more.
Helix TBE
Carbon intake elbow to air box
PE850's
Walbro pump
Spearco TMIC
Xede...i would of rather had a flash in hindsight....

But to get that same 400 WHP on street gas...U would need a bigger turbo..like a rotated GT30r with a .82 housing, FMIC and maybe some good headers...and some good luck...and only then u would make 400 on a high reading Dyno-jet.


BTW my motor went..so kids don't try this @ home.