STI turbos'
 

I was wondering what turbo you guys would choose for the STI. I dont plan on upgrading for a while(if Necessary) but i wanted to get some good ideas. I want a turbo that can help get me to about 425whp-500whp, but i want a turbo that will spool quickly enough for some out of the corner power. Should i just keep my stock turbo?
You guys are probably are all at the charity run sorry i could not make it up there. thanks for everyones time and help

500 hp at the wheels is a whole hell of a lot of power. Making that much power means redoing basically every system in the car. Otherwise it's no different than making a WRX get to 600ish horsepower too. More importantly, the car wil become extremely one-dimensional. Well, two if you count dyno ownage. :P But forget about road racing or autocross with a turbo that big.


Edit: As this is my 555th post, I am no longer permitted to post further, so you'll have to get details from the rest. ;)



555! w00t!

Sweeeeeeet :twisted:

Yah are you sure you want 425 at the wheels eventually?

That is a ton, like Kevin said you have to consider the whole concept of the car with that rather than just a turbo.

reply
 

should i just keep stck turbo?

Re: reply
 

Not necessarily. A VF22 is an excellent first step. Beyond that there is some debate. But, with the larger block, the VF22 on the STi will feel a whole lot like a VF30, or even something slightly smaller on a wRX- only much faster. :) I personally am planning a STi block/VF22 combo for my RS. Should be a great combination of drivability, low lag, and good power.

What do need this much horse power for :?: Drag, street autox wheel to wheel :?:

I think Eric has a geat question... Why HP? What do you want to do with the car? If somebody starts woth HP, it usually means they want a drag car. If you want to turn, that is further down the list.

I would also guess that you can get a significantly more power out of the stock turbo by upgrading the exhaust, intake, and ECU before you run out of turbo.

Yeah there's another 50 whp in the stock turbo exhaust and ECU work. You know better than to suggest an intake though Dean. ;)

OK, I had forgotten about STI boost creep, so the order should probably be Wastegate port, flash, exhaust, flash... Somewhere in there, replaceing the stock paper filter with a high flow, snorkle mod(Does the STI have a snorkle?), and/or intake wouldn't hurt. Despite what Kevin thinks, intake is not just a new peice of pipe and a cone filter. :twisted: And exhaust can be as simple as gutting the down pipe all the way to full turbo back...

There are two kinds of intake mods- ones that disrupt the MAF signal, and ones that don't. One has the potential to cause premature engine failure, and the other doesn't do squat. So why get either one? I'm not personally sold on the whole different filter aspect. I personally don't see how it makes a big difference, especially on a forced induction car. And besides, filtering the intake air to keep dirt and grit out of your turbo is MUCH more important than 5 hp. The silencer mod is more for sound purposes than for power gains.

serious tuneres might take the chance with the dirt and grit to get that extra 5 hp. 5hp my not seem like much but every horsepower helps.

I would disagree. If you can find me a shop that recommends intakes on a Subaru, and knows Subarus well, then I will show you a shop that is more interested in the margin they make from intakes than in making you faster.

click here for a good explanation of why intakes are unnecessary at best, harmful at worst.

After reading that i further understand. thanks

It's on I-Club, it must be true... :D

I'm not sure I'd use the word "squat". Physics is physics. The shorter, and less resistant the path; the colder and higher initial pressure the air charge; the better, period. I realize we are takling about small numbers, but everything helps, and some of these are fairly low to no cost mods.

The WRX, and STI have relatively poor engine bay venting, especialy at no to low speed. The the TMIC sitting almost right on top of the turbos doesn't help it any... Every little bit helps is all I'm trying to say.

More is indeed more power to be true. But this particular method, to me at least, isn't worth the cost in terms of hotter intake air, and more importantly the squirrely MAF readings caused by changing the intake tract. 5 "free" horsepower would be great- 5 hp that may very well have the effect of shortening your engine life? Not worth it to me.

That is a seperate matter entirely from discussing the merit and efficiency of the stock plastic intake parts. Fact is, they are borderline awful. But, the ECU is expecting the MAf reading to be true to the calibrations based on that suckiness. Plus, you can't change the efficiency all THAT much, especially on a turbocharged motor.

Also remember, the supposed power gains of changing an intake come from tweaking the MAF signal. This is something far better achieved by tweaking the other side of the fueling equation through ECU remapping.

As for the fact that I linked an i-club thread, I did so because I wrote most of the pertinent posts in it, and it saves me the trouble of repeating myself. My views are formed after absorbing quite a bit of first and secondhand knowledge from several sources, most prominently Shiv, Nate, and my own understanding of how electronic engine management works. It's been backed up by dynomometer testing. When I finish my swap, I plan to find a way to conduct yet another semi-scientific test of various intakes to see how much difference the theoretical efficiency difference makes, when taking proper tuning into account.

If there is a lot of hot air in the engine bay shouldn't we do something about it? we can put a FMIC to get rid of heat soke, and we could also put a louvered hood in witch should reliese the engine bay heat very quickly(the faster speeds the better cooling). would the engine bay be cool enough to put an intake on it? there wills till be heat coming off the turbo but it might releise qucik enough not to effect the intake

I do believe a ECU tune was part of every step of my suggested order: "Wastegate port, flash, exhaust, flash... Somewhere in there, replaceing the stock paper filter with a high flow, snorkle mod(Does the STI have a snorkle?), and/or intake wouldn't hurt." Doing any intake changes in association with one of the other steps imediately prior to a flash, should not yield any "engine shortning" effects.

I also have an ongoing issue with the supposed danger of CAIs. In one breath people comment on how incrediably inteligent the Subaru ECU is, and then in the next claim it can't handle a MAF reading that is a little out of whack. What exactly is the tollerance for MAF sensor callibration, and what is the variation in stock intake tract flow? All of a sudden, the ECU is going to ignore EGT, knock, and O2 Sensors, and take the MAF as gospel? I just don't buy it.

I would bet the ECU actually continiously balances all of the sensor inputs into it's A/F calculations/settings, but I admit, I do knot know what it does. I have actually seen next to zero actual science behind the CAI discussion. Most is anecdotal at best, and often associated with people who have done a significant amount of other tuning, not just the CAI.

I am not saying CAIs are the greatest thing since sliced bread, only that an optimized intake tract can enhance the performance of just about any vehicle. Optimizing it in some way in association with other mods and an informed flash is probably a good thing.

FMICs are great, but represent quite a significant increase in piping which of course impacts flow.

The fender is probably the coolest area nearby to draw air from, and while I have not put a monometer on it, the fender may actually have a slightly higher than ambient air pressure at speed.

Everything is a trade off... Getting rid of heat is good, increasing drag is not. Properly designing hood vents so they purge heat in static and various dynamic conditions while minimizing drag is not trivial. The Subarus aren't that bad at speed, but like most modern cars, aerodynamics and styling make factory hood vents undesireable, and most aftermarket companies do not have the money for the wind tunnel testing that would be required to actually do a good job.

Well Matt turned a 230 on the dyno with a drop in and I pulled a 226 with
a ralitek intake :? I simply like to hear the blow off in the car and thats only thing my intake does :D But mike also with the same drop in pulled a 216 :? Arco gas :cry:

:lol: :lol:
Dean - we have the same set-up as the WRX so yes snorkle included :D

Would it be worth going to a FRIC? or would you loose to much flow?

FRIC? I'm guessing you meant FMIC, but whatever, it all depends....

I guess we still don't know what your goals are for this car except your wish for 425-500WHP.

Longer path = slower response. Colder charge air = More power.

Bigger turbo = slower response, and more power...

Everything is a trade off. Oh, and it all costs $$$s, so budget is also a consideration.

my ultimate goal is to make a bad ass rode course car, i would like a lot of power out of the hole, so i dont think a big turbo would be to wise. like i said i wanted it to be a rode course car wich means i will need the proper cooling to keep my motor in good condition.

can i do a FMIC with a smaller turbo? would that even out?

Fmic will give you more lag on the bottom(out of the gate) :!:
Dean did the math if you look close he said further the IC is the more lag you will have :twisted:

I do the waste gate larger fuel pump and pressure reg. new mapping for the ecu, turbo back with a single hi flow cat and SUSPESION (coilovers ect.)
But not in that order :!: First drive the car stock and find out what you need :) Suspension would be first in my book! HP doesnt = WINS

What he said. If you want a road course car, there are many things to do before power. Also are you thinking actual door to door racing, or just HPDE type events? I don't know your driving experience...

The STI is so quick and handles fairly well from the the showroom floor, unless you are a very experienced performance driver, i would suggest driving it stock for a while. Learn to drive it at autocrosses, or on the track, and then you will know what upgrades you want, you won't need us. :(

That said, the upgade order looks something like this.

1. Seat Time
2. Harnesses. With an 04 STI, Seats may be almost as important unless you have a large butt.
3. Seat Time
4. Wheels/Tires. you will learn more on crappy tires, so this may be questionable. They will make you faster, but not necessarily a better driver.
3. Seat Time
5. suspension (Order depends on budget)
a. Sway Bars
b. Coil overs
c. Front Camber/caster plates
d. Rear camber/caster adjustment of some form. Bolts/arms...
6. Did I mention Seat time?
7. Did I mention Seat time?
8. Did I mention Seat time?
9. Did I mention Seat time?
10. Any power mods.

Come out this weekend and ride with some of us. You will be amazed what stock boost, mostly suspension street tired WRXs can do in terms of crushing some very expensive sports cars, and what a basically stock STI can do as well.

Like Dean said... seat time is #1!!

Also, like Dean said... the STi is *very* capable out of the box... You've seen my car and all the crazy work I've doe to it... and to be honest, it's just about the equivalent to a stock STi: I have a little bit better handling due to the coilovers, but a stock STi will kill me on power.

In fact, right now MattR (who's racing a Street Tire A-Stock STi) and I are *tied* for 10th in the Open PAX standings. :lol:

Instructional Seat Time.

Passenger Seat Time with someone who is an expierenced driver(Dean is a great outlet) in car close to yours.

Seat Time means driving in events, in case that is unclear.

after changing the turbo on my wrx, i have concluded several things. if you do this, even with good tuning there will be lag. i put a garrett t-28 in my car(a very efficient and low lag turbo which isnt that big) and even with good low end tuning with my UTEC there is still a bit of lag. not a whole lot , but definitly not good for autocross as any one who saw it get beat up by stock wrxs would tell you when my bro drove it out at stead. straight speed and freeway with the full exhaust and turbo is great. when i get a decent tank of gas its more power than i really need on the street.(240whp @ SS) another thing is that if you plan on driving it around town they new turbo will get s**t for gas milage. and with gas prices the way they are currently this will set you back a pretty penny after filling up twice a week for a while.

my suggestion would be to get the power out of the ihi turbo thats in the sti. the sti makes great low end power and has a lot of low end torque. if you upgrade the turbo, you will be sacrificing torque for power since most of the tubos you can buy make power on the top end(just like mine). even with good spool up you will not gain torque numbers as fast at hp. not enough low torque means no good for auto x! my car might put down more on the dyno than an sti but there is no way even with my suspension could i beat an sti on a road course. on the street going straight, yes, but not racing auto x.

deans suggestions are also good. suspension is SUPER important right along with braking and yes sitting in your seat comfortably. i honestly think after everything that 500hp at the wheels on a stock sti block is nearly impossible without turning it into a strictly drag racing car, or running NX. the block just wont handle the boost, nor will the transmission, driveline, etc. get the power out of the stock turbo, im certain that you can attain 300+ at the wheels on the stock turbo by modifying around it(exhaust, intake, fuel etc....).

ryan

Wise words, based on great 1st hand experience! The stock STi turbo is actually a very good match to the STi motor for across the board power and low lag. With a wastegate port, turbo-back exhaust, and a remap, I'll bet you can see close to 275hp at the wheels all w/o adding lag to the system.

I would actually bet you can reduce Lag with those upgrades.

I did forget Brakes on my list. But, you have an STI, so not much to do there. For a Street/Autocross car, a good set of pads should e fine. On a track car, they are critical good pads, and possibly better rotors would be on the list. Pads probably belong right after tires/whhels, and anything else in with suspension somewhere.

Sorry guys, haven't been loggin on so much these days..
anyway, DAMN 450-500 WHP! that's a bejezus amount of power.. At that point, the car probably wouldn't be an every day driver anymore. Big turbo = $$$ in gas. :lol:

Like Dean and scott said, learning to drive the car well is VERY important.. as i know from experience :( .. however, if you want to have an STi that is puts huge numbers on the dyno and has great straight away speed.. There aint no one here that's gonna tell you how to spend your 15,000 dollars.. :D

500 whp is a ridiculous amount of power in any car, especially considering the huge drivetrain losses your AWD cars have. With a 20% drivetrain power loss (that number was just pulled out of my ass), that's 625hp at the crank... you've got to be kidding me. That's well into dedicated race motor territory - assuming you could even get a small motor like that to put out that much, the car will not work well for normal street driving, break things all the time, and be a general pain in the ass.

500 at the wheels is more than EasyStreet's 9.6s drag car puts down at the wheels. And they had to build a custom semi-auto tranny to hold the power. EasyStreet's car is said to have over 700hp at the crank. Drivetrain loss is *very* significant in a WRX/STi.

My car puts "only" about 200hp to the wheels, and it's certainly not a slow car. More than twice that power would certainly not be very streetable, and would cost well more than the price of the car itself... you'd probably need:

- EJ22TT closed-deck short block bored/stroked to 1.6L+, all forged internals
- Custom intake w/ dry-ice box
- GIANT turbo
- custom FMIC
- headers back custom exhaust (no cats)
- 800cc injectors, fuel rails, and a beefy fuel pump
- stand alone engine management
- custom clutch, tranny, differentials, and probably axels to handle the power
- And you'd need to run 110 leaded minimum... all the time
- And nitrous... all the time :shock:

And after all that, Dean would still kill you at AutoX... ;) :lol:

However, if you really want to go big... I'm sure ESX will adapt their 740hp WRX kit to an STi:

Just remember where a car like that is at home:
http://www.esxmotorsports.com/structure/740a.jpg

Personally I think it would be easier just to go with the dual EJ257 mod. ;)

How's that? An extra motor in the trunk? Where would your monkey live!?

I dont think he is even reading these threads anymore :!: :shock:

well lets think real quick! you mods intell a different engine hhhmmm. HE HAS A STi right? sorry cap lock :P

eh? To get an STi up to 500whp, it's going to need a different engine! 500whp is probably around 800hp at the crank!

To put that in perspective, Indycars & Formula 1 cars vary from 650-900+hp at the crank.

Hey, great, thanks... for blowing all our our hard work at convincing n00bs that stupid-fast cars can't turn worth a damn. :rolleyes: :evil:








:wink:

Well, you can be consoled that an F1 car weights about 1/3 our car's weight and costs about a million bucks. So you can have high horsepower and handling, but it'll cost ya, and it's not exactly a "grocery getter". (Although, if you used an F1 car to go to Scolari's, you'd be the biggest PIMP alive!)

Fast, Cheap, Reliable... choose any 2.

Werd y0. And the reason I don't have fast yet is that I want reliable and my wallet wants cheap. :P