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Old 02-10-2010, 05:43 AM   #1
1gcrazy
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Default Which turbo for 350-360 whp on stock tranny.

Ok fella's Mod list:

05 wrx
Gruppe S UEL header
Catless uppipe
3" turbo back catless, SPT catback
Wideband not that it matters.
70mm aps CAI
BPM Intake tube
APS Dr525
800cc cut stockers
Wally 255
ACT 2600
Gruppe S Flywheel
E85 once tuned....

Stock 5 speedFYI, i'd rather roast my clutch that blow up my tranny... I like to think I know how to drive. I go easy on it though... in fear.
Stock 2.0L

Anyway, I have the stock PnP Tdo4 and I need something bigger...
I like highway driving...so I dont want something thats gonna fall flat on its face.
I also want something that'll spool right around 4k or under.

I prefer drag racing but I also dig rallycross and road racing.

I've been considering:
20g
18g
68HTA
E316g
FP green

The less I spend the better. I also WOULD LIKE to buy used if I can. But i'm just not sure which one to focus on. I wanted a used 68HTA but no one is selling at the moment.

I'm also planning on a 6 speed soon. So i'd like to grow into a larger turbo but still spools fine at low enough boost to keep my tranny alive.

Harvey aka, The Boost Creep in Colorado is going to be tuning the car.


CLIFF NOTES, need the best highway/road race turbo that wont kill my tranny on conservative driving.
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Old 02-10-2010, 06:07 AM   #2
jaxscuby
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most of the stock 5 spd that went kaboom where over ~320 whp..
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Old 02-10-2010, 06:51 AM   #3
1gcrazy
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Quote:
Originally Posted by jaxscuby View Post
most of the stock 5 spd that went kaboom where over ~320 whp..
What were the ~torque numbers at 320?
Also what year tranny's are the generalizations being based off of?
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Old 02-10-2010, 07:25 AM   #4
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Quote:
Originally Posted by 1gcrazy View Post
What were the ~torque numbers at 320?
Also what year tranny's are the generalizations being based off of?
any 5 speed
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Old 02-10-2010, 07:48 AM   #5
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I had a td05H 18g 7cm on my 2006 WRX. I did fine with the stock 5spd and was putting down 300whp and 330wtq @ 18.5psi for a long time with no issues. If you dont beat the piss out of it you should be ok. I even ran a tune with meth for a while putting down 340whp/400wtq @ 21.5 psi(could have boosted up to 24psi but my clutch started slipping over 400whp and tq). I did eventually go to an Sti 6spd only because I wanted to drive a little harder. I never really doubted the 5spd. I used light duty clutch kits with organic discs, like the Exedy stage 1. This allows a little bit of slippage which is easier on the gears shock wise.

The only thing is I believe the gears in my car are just a little wider than 02-05 WRX's.

If you want more room to grow or if you do decide to opt for a trans upgrade I would go with a 20g or ATP turbo...
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Old 02-10-2010, 08:49 AM   #6
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Quote:
Originally Posted by 1gcrazy View Post
CLIFF NOTES, need the best highway/road race turbo that wont kill my tranny on conservative driving.
really??? Highway???? you know all the boys who do the "highway" have large frame turbos, right? Don't be sad they walk you!!!! Stepping up to a 20G is just like a stock EVO9 turbo.

If you drive conservatively you will never kill your tranny.
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Old 02-10-2010, 08:56 AM   #7
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If you're just looking for top end, I'd stick with the 18G or 20G. Do some reading on modded stock injectors with those turbos. Find out what the IDCs were. You might need more than modded stockers to run those turbos with e85.
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Old 02-10-2010, 11:51 AM   #8
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30r, do it. full boost at 4k
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Old 02-10-2010, 12:26 PM   #9
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im running a td06h 20g....the power is like a lightswitch....nothing and then BAM!


can't be good on the tranny....but i havent tried launching it yet out of fear of grenading it. basically, i wouldnt do anything over a 16g on these cars unless you plan on going 6m/t later down the road. I'm going 6spd in the spring.
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Old 02-10-2010, 12:44 PM   #10
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Your stock motor will not handle that power for long. And if your motor is built, this is the wrong forum.

Also, if you have that much power and ever intend to use it, then kiss your transmission good-bye. If you can't afford to build the motor and transmission, you can NOT afford 350+ whp.

And also, on what kind of dyno and fuel do you intend to make those numbers?

You will need a FP Green or 30R to REALLY hit those numbers on pump, though a 20G-8cm might get you close.
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Old 02-10-2010, 01:09 PM   #11
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My tranny went at 78,000 miles with a VF39. RA gears now= bring it on
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Old 02-10-2010, 01:45 PM   #12
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I reached around those numbers on similar mods to yourself with an 18g 8cm^2 / 44mm ewg / and 50/50 meth with 24psi...Different dynos will give you different numbers but my set up traps 116 plus or minus 1 consistently so I'de have to believe the numbers are fairly accurate...

On pump alone I'm with audio, green at the least, a 20g may get you there but why risk being dissapointed.

Last edited by Cards2323; 02-10-2010 at 01:59 PM.
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Old 02-10-2010, 01:54 PM   #13
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Just go for a green. I started with a vf30 and that didn't cut it. Than again I have a built tranny that can take it.
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Old 02-10-2010, 02:00 PM   #14
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Out Of The Turbos You Listed The Green Is The Only One That Will Make That Kind Of Power. A 30r Would Also Get You There. If You Ran Meth You May Make Those #'s W/ A 20g.
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Old 02-10-2010, 02:37 PM   #15
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Quote:
Originally Posted by David L. View Post
I had a td05H 18g 7cm on my 2006 WRX. I did fine with the stock 5spd and was putting down 300whp and 330wtq @ 18.5psi for a long time with no issues. If you dont beat the piss out of it you should be ok. I even ran a tune with meth for a while putting down 340whp/400wtq @ 21.5 psi(could have boosted up to 24psi but my clutch started slipping over 400whp and tq). I did eventually go to an Sti 6spd only because I wanted to drive a little harder. I never really doubted the 5spd. I used light duty clutch kits with organic discs, like the Exedy stage 1. This allows a little bit of slippage which is easier on the gears shock wise.

The only thing is I believe the gears in my car are just a little wider than 02-05 WRX's.

If you want more room to grow or if you do decide to opt for a trans upgrade I would go with a 20g or ATP turbo...
See, I've read that my tranny is stronger than previous years. I'm not sure how it stacks up against the 06 and up but Harvey concurred.

Quote:
Originally Posted by FuJi K View Post
really??? Highway???? you know all the boys who do the "highway" have large frame turbos, right? Don't be sad they walk you!!!! Stepping up to a 20G is just like a stock EVO9 turbo.

If you drive conservatively you will never kill your tranny.
LAWL, I'm not looking to be a Supra killer on the highway. I just want some oomph. My tiny do4 feels like it wants to shoot itself. Cap straight to the waste gate.

Quote:
Originally Posted by WhyHelloOfficer View Post
If you're just looking for top end, I'd stick with the 18G or 20G. Do some reading on modded stock injectors with those turbos. Find out what the IDCs were. You might need more than modded stockers to run those turbos with e85.
I asked Harvey about this except I asked him about the 68HTA. The 20g and beyond would be more of a lower level tune. My main concern is reliability for at least a year or two....

Quote:
Originally Posted by Audiosavvy View Post
Your stock motor will not handle that power for long. And if your motor is built, this is the wrong forum.

Also, if you have that much power and ever intend to use it, then kiss your transmission good-bye. If you can't afford to build the motor and transmission, you can NOT afford 350+ whp.

And also, on what kind of dyno and fuel do you intend to make those numbers?

You will need a FP Green or 30R to REALLY hit those numbers on pump, though a 20G-8cm might get you close.
It isn't built. Yet. I don't really want to tune to break, then fix. I'd rather build then tune so i'm not stuck anywhere.
E85 as stated above. It is plentiful here in Colorado and Dyno Dynamics.
You said my motor wouldn't last long. In your opinion, based on that statement, which part do you feel will fail first? Rods? Head gaskets?

Quote:
Originally Posted by makeitlookeasy View Post
Just go for a green. I started with a vf30 and that didn't cut it. Than again I have a built tranny that can take it.
See thats what i'm worried about. I don't want to pay Harvey to tune twice because I didn't do enough research. It's money down the drain. Is the green really usable at 300whp on E85? And even if its at E85. I could just step down to 91 to make my life a little easier when finding a pump.

I'm very indecisive. I'm about ready to just take a poll...
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Old 02-10-2010, 02:41 PM   #16
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Quote:
Originally Posted by 1gcrazy View Post
It isn't built. Yet. I don't really want to tune to break, then fix. I'd rather build then tune so i'm not stuck anywhere.
E85 as stated above. It is plentiful here in Colorado and Dyno Dynamics.
You said my motor wouldn't last long. In your opinion, based on that statement, which part do you feel will fail first? Rods? Head gaskets?

Pistons. And then rods. In that order.

If you're going with E85, I'd go with a 20G-8cm
If it's an unmolested Dyno Dynamics, at that altitude, you may still need a 50lb turbo, like the Green or a 3076.
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Old 02-10-2010, 04:06 PM   #17
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Quote:
Originally Posted by Audiosavvy View Post
Pistons. And then rods. In that order.

If you're going with E85, I'd go with a 20G-8cm
If it's an unmolested Dyno Dynamics, at that altitude, you may still need a 50lb turbo, like the Green or a 3076.
Dyno's at 20-22% correction.
I thought that the pistons held up as long as you had ZERO knock and E85 would essentially protect me from that. Do they crack? I guess i'm confused. I figured rods would go before the pistons. Maybe i'll search about engine failure at that hp level.
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Old 02-10-2010, 07:35 PM   #18
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There is a lot more of this kind of reliability data on the 2.5L. Figure that 400 WHP on the 2.5L is getting pretty scary for the stock pistons on the 2.5L, some even use 350 WHP as thier limit. On a 2.0L, similar cylinder pressures will happen at ~20% lower HP values. 400 on 2.5L = 320 on 2.0L | 350 on 2.5L = 280 on 2.0L.

If you're talking 350 on the 2.0L, that's ~440 on the 2.5L. Go to the 2.5L forum and talk about running 440 WHP on the stock ej255 / 257 pistons. See what kind of response you get.

Now factor in that ej205 rods are significantly weaker than ej255 / 257 rods and 350 is really pushing a stock ej205.

Cast rods and pistons are somewhat of a crapshoot at that level. Cast has some inherernt inconsistency in terms of when something breaks. It's kind of pointless arguing whether rods or pistons are weaker at that power level, as you're definitely in the danger zone for both.

Last edited by Concillian; 02-10-2010 at 08:17 PM.
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Old 02-10-2010, 07:45 PM   #19
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Quote:
Originally Posted by Concillian View Post
There is a lot more of this kind of reliability data on the 2.5L. Figure that 400 WHP on the 2.5L is getting pretty scary for the stock pistons on the 2.5L, some even use 350 WHP as thier limit. On a 2.0L, similar cylinder pressures will happen at ~20% lower HP values. 400 on 2.5L = 320 on 2.0L 350 on 2.5L = 280 on 2.0L.

If you're talking 350 on the 2.0L, that's ~440 on the 2.5L. Go to the 2.5L forum and talk about running 440 WHP on the stock ej255 / 257 pistons. See what kind of response you get.

Now factor in that ej205 rods are significantly weaker than ej255 / 257 rods and 350 is really pushing a stock ej205.

Cast rods and pistons are somewhat of a crapshoot at that level. Cast has some inherernt inconsistency in terms of when something breaks. It's kind of pointless arguing whether rods or pistons are weaker at that power level, as you're definitely in the danger zone for both.
Good reasoning/info.
Some other threads worth digging through for the OP:
http://forums.nasioc.com/forums/showthread.php?t=969739
http://forums.nasioc.com/forums/showthread.php?t=266967
http://forums.nasioc.com/forums/show...php?p=28971992
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Old 02-10-2010, 08:09 PM   #20
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As far as tranny goes, You can get to this level of power on lower torque if you control boost (and therefore torque) at lower RPM, raising towards redline to keep max torque at a controllable level. I think 350 HP at 7100 RPM is around 260 torque at redline. Stock cams don't really like that, but I think a Dom 2.5 or Green might get you there. I don't think a 20G will. If you ramp boost, you can keep <260-270 torque and the gears should be okay with that if you are good about keeping shock loading to a minimum.

There isn't a whole lot of reason to shoot for 350 on stock tranny, though. People have real problems launching without either spinning tires or bogging with a turbo that large on a 2.0L. Drag radials can fix the spinning, but drag radials + launch control = goodbye stock tranny. I'm pretty sure best drag times on stock manual driveline are on 18G size turbos.

Road racing a turbo that big is not a good thing either. Almost every road course I've seen has at least one turn that's slow enough you'd be exiting in 2nd out of the powerband of a turbo that large.

I think a turbo that large only works well with modification to the engine to rev more and / or the tranny for a shorter 2nd gear.

Otherwise it's really just bragging and being able to show a line that goes "this high" on a dyno. If that's what you want, well, get an 18G and pay the dyno operator apply a large enough correction factor.

Last edited by Concillian; 02-10-2010 at 08:20 PM.
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Old 02-10-2010, 08:51 PM   #21
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just for ballpark info...
even RA Gears are only rated for up to 285ft/lbs of torque and it's the torque (or the abrupt engagement of an agressive clutch) that will kill the 5 speed fast.
At the HP/torque levels that you're asking for..
1) your engine will lose dependability/longevity
2) the increased HP and torque will make something else in the powertrain wear or break prematurely.
I'm on my 3rd engine and transmission due to HP mods so trust me when I tell you to be carefull what you wish for.
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Old 02-11-2010, 01:44 PM   #22
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Quote:
Originally Posted by Concillian View Post
As far as tranny goes, You can get to this level of power on lower torque if you control boost (and therefore torque) at lower RPM, raising towards redline to keep max torque at a controllable level. I think 350 HP at 7100 RPM is around 260 torque at redline. Stock cams don't really like that, but I think a Dom 2.5 or Green might get you there. I don't think a 20G will. If you ramp boost, you can keep <260-270 torque and the gears should be okay with that if you are good about keeping shock loading to a minimum.

There isn't a whole lot of reason to shoot for 350 on stock tranny, though. People have real problems launching without either spinning tires or bogging with a turbo that large on a 2.0L. Drag radials can fix the spinning, but drag radials + launch control = goodbye stock tranny. I'm pretty sure best drag times on stock manual driveline are on 18G size turbos.

Road racing a turbo that big is not a good thing either. Almost every road course I've seen has at least one turn that's slow enough you'd be exiting in 2nd out of the powerband of a turbo that large.

I think a turbo that large only works well with modification to the engine to rev more and / or the tranny for a shorter 2nd gear.

Otherwise it's really just bragging and being able to show a line that goes "this high" on a dyno. If that's what you want, well, get an 18G and pay the dyno operator apply a large enough correction factor.
My 20g does hold 350 at redline (I lose 10 hp from peak at 6500 to redline), and I don't believe the turbo is quite max'd out yet either. I'm sure a front mount & EWG would open a fair chunk more but I've pushed the stock block as far as I am comfortable with.

In addition, the lag on a good setup isn't nearly as bad as most people think it is. I hit full boost earlier than some 16g's and 18gs I've seen on this site (I'm full at ~3700-3800 in 4th) and I have seen 20gs spool even a bit faster than that. The difference is how hard you taper up top and mine doesn't taper that much at all to 7k. The only gear that feels prohibitively laggy to me now is 6th when I'm well below 3k.

As far as the transmission goes, I ran RA gears at the dragstrip for the midwest shootout on my 100 octane tune and the gears survived (granted I was sally launching only into the high 1.8s and fully letting up between shifts - just there for fun). But I'm sure if I tried to drive the car to it's potential on the RA box one of the gears would have shredded. No way would I consider running a stock 5MT, the stronger gears (to what level can be argued from a million directions) + a bit shorter ratios were still intensely borderline for my car, I'm sure stock would eat itself in no time.
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