Turbo for biggest reliable power (350 HP?) on built EJ22T

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free5ty1e
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Turbo for biggest reliable power (350 HP?) on built EJ22T

Post by free5ty1e »

(EDIT 7/3/2013: Power level goal description / subject changed from [Turbo for big power (450 - 500+ HP) on built EJ22T] to [Turbo for biggest reliable power (350 HP?) on built EJ22T])
(EDIT 7/3/2013: Added new link with detail on IHI turbos, includes VF36 airflow rating!)


To go along with my Engine build thread here at viewtopic.php?f=5&t=52205, this will be the thread for discussing and selecting an appropriate turbo to match the power goal of 450-500+ WHP while maintaining some level of daily drivability / streetability and at or near stock reliability.

I have a VF36 twin-scroll ball-bearing turbo with the titanium compressor wheel and shaft that is good for up to 400HP, destined for my 1994 SS with a RobTune.

This thread is for selection of an appropriate turbo to match my 1991 SS's upcoming build, which will involve full forged internals.

I have gathered some good links with info on reasonably-available turbochargers below for reference, which is what I've been reading lately.

There are a couple reasons I'd like to stick with a Subaru turbo for this build, mainly the reliability factor, but that may not be feasible for the power levels I desire. I briefly researched Garrett T3/T4 turbochargers during the period when I was turbocharging my '99 Saturn SC2 (ended up with a T3 on a custom manifold before it got wrecked), and have looked into some TD05 Mitsu turbo options (maybe an 18G? 20G?) as well... but the actual selection of the turbo is proving to be quite difficult with all these options.

I'd like to try and save money on this build but I have a feeling I'll have to go with some new or custom parts in the turbo category. Or is there a widely-available used turbo model out there just waiting for my build? :)

As I am currently undecided on how I will go with compression ratio on the engine build, I may end up with a higher-than-stock CR to help make up for the turbo lag, but this warrants more research.

Any comments or thoughts or criticism would be greatly appreciated; as in my other thread, board consensus is important to me and will greatly drive the direction my build goes. It's hard to argue with the huge collective experience on here where consensus exists...


Thanks everybody!

---------------------TURBO REFERENCE LINKS--------------------------
Info on VF36

Ver.8 STI spec C Turbo

IHI Turbos - specs & faqs - incl VF36
VF36
Roller bearing version of the twin scroll VF37, also has a titanium turbine and shaft for even quicker spool. Same compressor housing as VF30/34, however twin scroll P25 exhaust housing provides slightly better top end output due to reduced exhaust pulse interference. This turbo is good for 400HP and used on JDM STI Spec C from 2003 onwards.
2ndHand Subaru Turbos

Turbos (incl. VF36)
IHI VF36
(430cfm, 250-325whp, Modification Required)
This is the standard equipment turbocharger used on the JDM V8-V9 Subaru Impreza WRX STI Spec-C Type RA. The VF36 is a twin-scroll turbocharger that utilizes a ball bearing design, a P25 exhaust housing, and Titanium (possibly TiAl?) compressor wheel for improved spool. It is essentially a fast spooling VF34.
Expect to achieve full boost with the proper mods and a quality tune between 2800-3300rpms. 2002-2005 WRX owners will need fuel upgrades for this turbocharger and proper engine management is highly recommended for all vehicles.
Last edited by free5ty1e on Wed Jul 03, 2013 7:15 pm, edited 2 times in total.
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
Legacy777
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Re: Turbo for big power (450 - 500+ HP) on built EJ22T

Post by Legacy777 »

Chris,

The turbo is just one piece of the puzzle and while yes it is an important piece, it is very interconnected with the engine and what you plan to do there. At the HP levels you are talking about I think the supporting systems, fuel, engine, engine management, piping, etc have a larger role to play than just the turbo selection, especially on an ej22t motor. So just because the turbo will support the horsepower, doesn't necessarily mean the engine will.

...power goal of 450-500+ WHP while maintaining some level of daily drivability / streetability and at or near stock reliability.
That level of power and daily drivability/streetability and/at or near stock reliability are at two completely opposite ends of the spectrum.

Additionally,
I'd like to try and save money on this build but I have...
I understand the desire to save money, but this and your comment about reliability, etc are a little contradictory, so I want to make sure you understand what you're getting yourself into. A build like this could easily stretch into the $10k range or more by the time you address things like upgraded transmission, fuel system, engine, engine management, turbo, intercooler, etc. If that number is way above what you had envisioned spending, I suggest you take a close look at your power goals and budget.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
MikeyMeyagi
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Re: Turbo for big power (450 - 500+ HP) on built EJ22T

Post by MikeyMeyagi »

no vf turbo will support 400whp so toss that idea. the rob tune is maxed out at 270-280whp due to injectors and maf.
to make that kind of power you will need a standalone and a gt35r/pte6262/borg s300 size turbo. get ready to spend ALOT of money to make it work and be reliable. going above 350whp on a subaru is not cheap.
oh, and i hope you have a 6mt. 5mt's will shatter at the thought of that kinda power.
94 Supra Turbo 6 speed. build in progress
98 Lexus GS300, single turbo 2JZGTE swap. daily driver
93 Impreza wagon, home brewed n/a-t ken block themed winter drift missle

*sold*
94 Alpine Sport Wagon... STi conversion, rotated turbo etc
free5ty1e
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Re: Turbo for big power (450 - 500+ HP) on built EJ22T

Post by free5ty1e »

Thanks Josh and Mikey, that's good food for thought. I'd never gone down this path before so I figured this is a good place to start (along with the engine build thread) so I can make some intelligent decisions about how to proceed.

I certainly understand that post #1 above looks to those with experience like "I want it all" -- which I DO! :)

I figured the first real response I got would be telling me I needed to find some compromise... so that was expected, lol. Thank you for providing the actual starting point of this discussion :)

I wonder if I should consider saving the VF36 for my '91 SS build, and look into other smaller turbo options for my '94 which will be using stock internals all the way? Perhaps 400HP is a more reasonable power goal for daily driveability and reliability while still capable of tearin' it up...

I'm adding a link to this thread into my engine build thread so they are cross-referenced. I look forward to learning more about other members' experiences with regards to big turbo power on daily drivers, or at least streetable cars. Race-only / track day cars are not of interest to me.... if I can't drive it to the track, race it for a while, and then stop at the grocery store on the way home, then that's not what I want.

Do we have any sort of consensus on how much power can be reasonably expected without sacrificing streetability completely?

A 6MT is indeed in the plans... although later in the build, before I bump up the boost.

(I am not dead set on spending shit tons of money just to get a little extra power, I guess I'm more concerned with finding an impressive power level that can be reliable and streetable -- I can always add more stages to the build and take it a bit slower, which is probably what is going to happen LOL)
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
MikeyMeyagi
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Re: Turbo for big power (450 - 500+ HP) on built EJ22T

Post by MikeyMeyagi »

from what i have seen the stock shortblock wont take 400hp either without the cast pistons breaking, or the rods bending.
my buddy dave recently dyno'ed his ss with a built 22t, vf34, robtune and other supporting mods and made 270whp. above that, maf, injectors, and turbo will start to max out.
94 Supra Turbo 6 speed. build in progress
98 Lexus GS300, single turbo 2JZGTE swap. daily driver
93 Impreza wagon, home brewed n/a-t ken block themed winter drift missle

*sold*
94 Alpine Sport Wagon... STi conversion, rotated turbo etc
free5ty1e
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by free5ty1e »

OK, so perhaps my original power goal was a bit too ambitious to be reasonably attainable in the fashion I desired.

I've edited the subject to be a bit more reasonable and accurate -- I am looking to create a plan for a staged engine build for a streetable / reliable 350HP setup on a built EJ22T.

I still have yet to find accurate information on my VF36, like a compressor map for instance... that would help me figure out which car to put this twin-scroll turbo onto.

This plan will indeed involve a front-mount intercooler, I've come up with custom pipes before and -- especially learning from what worked well in that setup and what didn't -- I'm sure I could do it again... and much better. Rolling or welding up a lip onto the end of the custom-bent exhaust piping used for the intercooler hard pipes, for instance, and using T-bolt clamps instead of worm gear clamps, would improve the setup quite a bit from what I have in the '94.

Anyway, with the adjusted power goal.... I'm interested to hear thoughts, suggestions, and criticism.

The 5MT is gonna be destroyed at or around 300 WHP, depending on how badly I treat / launch it... so perhaps a 6MT would be the last part of this build when I turn the boost up enough to surpass that power level. I'm not one to launch harshly anyway in most cases and think I could keep myself in check when carefully cruising around with enough power to destroy my 5MT while I save up for the 6MT...

Has anyone come across a compressor map or other actual info on the VF36? I'm seriously wondering how far I can push this turbo, and if it would work in this '91 build better than it would in my '94 with the stock internals.
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
free5ty1e
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by free5ty1e »

Found at least some actual information on the VF36 that may start to help (added to first post):

Turbos (incl. VF36)
IHI VF36
(430cfm, 250-325whp, Modification Required)
This is the standard equipment turbocharger used on the JDM V8-V9 Subaru Impreza WRX STI Spec-C Type RA. The VF36 is a twin-scroll turbocharger that utilizes a ball bearing design, a P25 exhaust housing, and Titanium (possibly TiAl?) compressor wheel for improved spool. It is essentially a fast spooling VF34.
Expect to achieve full boost with the proper mods and a quality tune between 2800-3300rpms. 2002-2005 WRX owners will need fuel upgrades for this turbocharger and proper engine management is highly recommended for all vehicles.
So, it looks like with my new power goal of ~350HP, the VF36 is juuuust about right for this build (430CFM, 325HP possible) and would possibly be workable with the RobTune550 that I have here.

I wonder if Rob can scale the maps on his tune to work with larger adapted injectors... ? I'll email him and inquire how feasible that might be. Hmm....
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
wtdash
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by wtdash »

As MM mentioned, and Rob will likely tell you, the JECS/AUTECs green labeled MAFs just can't handle enough air for over 300HP.

Rob is/was working on using the Nissan Z32 (?) MAF for more 'headroom' - I don't know the status of that.

GL,
TD
Turbo Subies:
'87 GL-10 Turbo - SOLD
'90 BJ EJ22T/DOHC & 5speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX -SOLD
'96 BD-turbo'd-SOLD
'98 SF - NA-T
free5ty1e
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by free5ty1e »

Ah -- indeed then that is understandable. Sounds like a reasonable first goal, can go further once a 6MT is installed and standalone engine mgmt is purchased.

Hey -- I seem to recall finding out with some earlier experiments with our MAF sensor and some documents Josh had handy (yep here it is, unfortunately that link -- 2 posts above this linked post of mine -- is dead) Our MAF apparently (from the info I referenced there) maxes out at 265CFM @ 4.5V. Anyone happen to know the specs for the JECS MAF? What CFM it reliably reads as maximum, and perhaps will it ready slightly above its max reading with less accuracy (up until closer to the 5V reference, maybe 4.9V)?

I've found a better reference site and have begun actually doing the math for our cars at stock boost levels in the stock configuration, the levels I've run recently, and some potential limits for the VF11 and my T-bird hybrid VF11 turbo. Then I can maybe make a decision on a big turbo for the built EJ22T down the line once the 6MT and engine management are in place.
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
wtdash
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by wtdash »

Per info I found (don't know where) the JECS can go to 420 CFM.

This LINKalso shows interesting info about the Hitachi vs. JECS MAF.

Clif's notes: The Hitachi MAF, around 155 g/s, the JECS about 220 g/s. My math shows a 42% increase!!

And just to clarify something, per Rob:
The step in the housing has nothing to do with the limit of the MAF. It is 100% a function of the the electronics inside the MAF.
So, upgrading to a physically larger MAF doesn't mean Jack.


Td
Turbo Subies:
'87 GL-10 Turbo - SOLD
'90 BJ EJ22T/DOHC & 5speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX -SOLD
'96 BD-turbo'd-SOLD
'98 SF - NA-T
free5ty1e
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by free5ty1e »

Oh perfect for the vf36 robtune550 setup! Thanks for that.

Sent from my SAMSUNG-SGH-I337 using Tapatalk 4 Beta
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
free5ty1e
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by free5ty1e »

wtdash wrote:As MM mentioned, and Rob will likely tell you, the JECS/AUTECs green labeled MAFs just can't handle enough air for over 300HP.

Rob is/was working on using the Nissan Z32 (?) MAF for more 'headroom' - I don't know the status of that.

GL,
TD
Just noticed this -- so the AUTECs green label black plastic Subaru MAF sensors are the equivalents of the JECS sensors? In this case, the Portland South Pick n Pull junkyard has 1 JECS and like 3 AUTECS MAF sensors sitting around, I discarded them after noticing the green label didn't say "JECS". Pulled 'em and everything. Excellent. :)
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
wtdash
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by wtdash »

^yep. All '90 and '91 automatics (manuals used hitachi like the turbos), and all ej18(?)/ ej22/ej25 '92-'98 legacy/forester/impreza + '99 legacy outback/gt (ej25) used them.
Turbo Subies:
'87 GL-10 Turbo - SOLD
'90 BJ EJ22T/DOHC & 5speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX -SOLD
'96 BD-turbo'd-SOLD
'98 SF - NA-T
MikeyMeyagi
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by MikeyMeyagi »

350whp reliably? built 22t/heads that flow/ FP green HTA/fmic/Hydra ecu/ done.
94 Supra Turbo 6 speed. build in progress
98 Lexus GS300, single turbo 2JZGTE swap. daily driver
93 Impreza wagon, home brewed n/a-t ken block themed winter drift missle

*sold*
94 Alpine Sport Wagon... STi conversion, rotated turbo etc
free5ty1e
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by free5ty1e »

MikeyMeyagi wrote:350whp reliably? built 22t/heads that flow/ FP green HTA/fmic/Hydra ecu/ done.

....bam! Thank you, sir. That is good info to have.
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
Legacy777
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by Legacy777 »

A couple comments....

I was close to 300 chp, but over 300 ft-lbs of torque with the 5spd and the 5spd was still working. I did happen to find a missing gear tooth....so I think if you treat it well it will work for a while.

Regarding the MAF sensor comparison, you might find this interesting. It's data points that Vikash pulled from the ECU for the two MAF sensors. You can see their response curve (air flow vs. voltage).

http://www.main.experiencetherave.com/s ... ansfer.xls

Lastly....are you wanting 350 chp or 350 whp. You'll lose about 50 hp or so through the drivetrain. I think 350 chp or 300 whp is more attainable without spending a lot more money. Plus I think you'll be plenty happy with 300 whp.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
free5ty1e
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by free5ty1e »

Thanks, that Excel file has good info! Interesting to note where the airflow sensors end up at maximum usable signal voltage.

Having never owned a car with that much HP, I'd imagine I'd be pretty satisfied with 300 WHP. For a while, anyway. lol

I was under the impression we lost far more power to the drivetrain; estimates I've seen on the Interwebs are around 25% power loss through a typical AWD drivetrain. So I'd need ~375CHP to end up with 300HP to the wheels.

It's close enough, just curious if anyone actually knows what kind of power losses happen through our AWD drivetrain?

I would definitely like to find the price point where I can get good power but it would cost much more to increase further. That seems to be at or around 350CHP, which will work for me. I can always plan upgrades later if this ends up not being satisfactory, but hopefully I'll be happy with it :)
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
Legacy777
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by Legacy777 »

When I had my car tuned at Fine Line Imports their tuner said stock STi's which should have 300 chp/tq put down 250 whp & wtq. So that's where my 50 hp drivetrain loss came from. A different dyno may show more or less loss. I think I may have posted them before, but here are my dyno plots

http://www.main.experiencetherave.com/s ... yno_plots/
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
blankdeluxe
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by blankdeluxe »

Legacy777 wrote:When I had my car tuned at Fine Line Imports their tuner said stock STi's which should have 300 chp/tq put down 250 whp & wtq. So that's where my 50 hp drivetrain loss came from. A different dyno may show more or less loss. I think I may have posted them before, but here are my dyno plots

http://www.main.experiencetherave.com/s ... yno_plots/
Usually 220-240 for a stock STI whp depnding on the dyno. But its also hard to say that with confidence. Depends on weather, time of day, type of dyno, and altitude as well as a handful of other factors. I haven't ever seen a bone stock STI at 250 though.
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Re: Turbo for biggest reliable power (350 HP?) on built EJ22

Post by Legacy777 »

They've only got 91 octane fuel in california too. I trust the tuner, and if that's what he said the stock cars put down, that's what they put down.

Here's a plot showing my car on 91 octane vs. a 2006 STi.

http://www.main.experiencetherave.com/s ... _dyno8.jpg
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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