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Old 07-08-2016, 10:52 AM   #1
joek92
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Default What is the fastest spooling turbo for STI EJ257

What is the fastest spooling turbo for the STI EJ257?

((I got a ragged VF39 & a Mellet rebuild kit. 17" wheels & 235/40 tires = 3.99 final drive https://tiresize.com/gear-ratio-calculator/ ))

Goals:
Peak tq in 3rd gear at or below 3k rpm
Safe tuned at or below 18psi
93 oct
No power or tq goals (well, slightly less than vf39, above td04)

I want a turbo for my 07 sti EJ257 that spools faster than stock vf43/39. Based on a few opinions, I think it's the vf35.

IHI VF35 (P15 turbine housing, larger than td04, no record of performance on EJ257 that I can find, except one blog post)

IHI VF22 http://www.iwsti.com/forums/2-5-lite...upgrade-2.html Many turbo lists claim this is the largest vf but I think they were written by non-US aka 2.0 L people. This link contradicts that and is verifiable. Drawback is risk of bearing failure.

16g with 6cm turbine housing - apparently 7cm is similar to VF39 turbine housing size. A 6 cm is stock wrx housing size. I don't think this will achieve the stated goals.


Spoolaids:
  • Twinscroll (expense, but probably best option)
  • Low mount turbo (Killer B demo car, OEM new WRX)
  • E85 (availability, mpg, component expense)
  • Nitrous/watermeth (failure risk, water/meth only benefit big turbos?)
  • Rocket anti-lag (turbine damage, expense, can a mere mortal even get it?)
  • Ignition anti-lag (want to try this)
  • Shorter gears (expensive, install time)
  • Cams? (is there a cam that shifts tq curve left?)
  • Smaller wheel & tire diameter (235/40r17 = 3.99 final drive vs. 3.90 for stock STI)
For autocross and similar tight turn/low speed applications. When the course is too tight to stay in high rpms. I'm looking for usable torque between 2000 to 4000 rpm. Top end restriction is fine.

Dsport explains natural traction control occurs in the rpm range above peak torque. However it's difficult to stay in that range, even stock turbo, when you have 15-20mph hairpins. Corner exit becomes hazardous.
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Last edited by joek92; 04-27-2017 at 10:59 AM.
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Old 07-08-2016, 12:39 PM   #2
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Basic premise:
The smaller the turbo, the faster the spool

Try checking out the various vendors, i.e.; Rally Sport Direct just to name one, plug in your car and look at the results for turbo applications. Usually, the turbo specs w/volume, total CHP possible are listed

You can then pick a couple you are interested in and check call the manufacturer directly for more specifics and recommendations.

You need to do some research on your own to get what YOU really want.
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Old 07-08-2016, 03:14 PM   #3
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Stock.
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Old 07-08-2016, 03:20 PM   #4
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Thanks but nobody has ever ran anything smaller than stock vf... or if they have then it's a secret or something.
Is there a reason for this that I don't know about?

I hate turbo sizing based on compressor maps and ve guesswork! Mainly because that's what I did with the turbo I have and it sucks.

The closest thing to just buying a bunch of turbos and trying them out is looking at dyno charts: rpm @ peak tq and boost.

Maybe forged performance or precision can help.
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Old 07-08-2016, 03:27 PM   #5
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Quote:
Originally Posted by nofriends View Post
Stock.
Maybe if I had an 04 transmission! The longer 2,3,4 gears are bull****. I've looked at swapping but too expensive.
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Old 07-08-2016, 06:26 PM   #6
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Look no further than a 16gxtr . That and e85 should be fun.
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Old 07-08-2016, 06:35 PM   #7
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My stage 2 '10 LGT gets full boost at 2500 rpm with peak torque at 2700. This is with the stock vf54 and low-mount setup similar (not the same) as the new WRXs. I have driven my buddies stage 2 '09 WRX and we both noted how it spools up ~500 rpm later.
I wonder if you could get noticeable results with a custom low-mount ELH and keeping your stock turbo.
My boost does drop off a cliff at ~5k rpm.
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Old 07-08-2016, 06:44 PM   #8
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Quote:
Originally Posted by danger1138 View Post
Look no further than a 16gxtr . That and e85 should be fun.
Yeah that's a good one. Wonder what size turbine housing is.

Last edited by joek92; 07-09-2016 at 09:06 PM.
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Old 07-08-2016, 06:55 PM   #9
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Bad news, if accurate.
Equilibrium Tuning says "The 16G-XTR does not spool faster than a VF turbo. It spools a bit slower and can make a bit more power up" from i-club.com

I get the idea that no turbo spools faster than the vf35. All other vf models have larger turbine housings. Now the question is, how will it feel.
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Old 07-08-2016, 11:15 PM   #10
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I have a built hi-comp 10.1to1 destroked long Rod motor. Running E85, aggressive timing and on the stock vf39 06 STI turbo I made 420tq/410hp with full boost at 2800rpm. I ran 22psi however it ran out of steam very quick my power band was 2800-6200ish "dependent on temp outside".

This was about 3 years ago and have moved on to an FPblack.

All I know is it was stupid fast and responsive for the street, but was perfect for streets of willow at willow springs race track.


The only reason I ran the VF39 on that setup was to try and break 500hp
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Old 07-09-2016, 01:43 PM   #11
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Damn that's crazy! Never heard of destroke/long rod but apparently it's tits if you made that much tq. I really want to see the dyno chart!

So much of the population live in flat areas I guess that's why response isn't a popular build direction. On the Tail of the Dragon east bound you realize how important it is.

Last edited by joek92; 07-09-2016 at 09:07 PM.
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Old 07-09-2016, 02:20 PM   #12
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Quote:
Originally Posted by Sarang View Post
My stage 2 '10 LGT gets full boost at 2500 rpm with peak torque at 2700. This is with the stock vf54 and low-mount setup similar (not the same) as the new WRXs. I have driven my buddies stage 2 '09 WRX and we both noted how it spools up ~500 rpm later.
I wonder if you could get noticeable results with a custom low-mount ELH and keeping your stock turbo.
My boost does drop off a cliff at ~5k rpm.
Thanks for the low mount suggestion. Killer B had a project car with this setup. Unfortunately I've already got too much money in this trap.

There are JDM twinscroll manifold on ebay but I already have Grimmspeed crosspipe, up pipe & 38mm ewg so... :/ Why didn't USDM sti get twinscroll!

My slow spool could be a boost leak. Today I am doing a boost leak test (capping all turbo inlet hose ports). Didn't cap them last time and that's probably why it wouldn't build pressure.
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Old 07-09-2016, 03:21 PM   #13
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This VF35 dyno is from either a WRX or FXT. Imagine what it would look like on a STI!

Quote:
Originally Posted by hex2bit View Post

Also, here's a comparison of the dyno graphs between the two turbos that I have put together to give you an idea of the difference between the two turbos. The components on the car are the same between both dynos, with similar conditions, on the same dyno (Dyno Dynamics Dynamometer). In all fairness, I had a small BOV boost leak during the VF35 run, which could have affected spoolup slightly. Notice this is a low reading dyno, reading a stock FXT at 150 HP


Notice a stock tuned TD04 has only a tiny lead compared to the VF35 for a few hundred RPM during its spoolup, which may have been negated if I didn't have the boost leak during the VF35 run. The power delivery of the VF35 is also a lot smoother and carries well to the redline. The smoothness is definitely noticeable on the street and very good for a daily driver. You don't really lose any lowend either, making this good for autocrossers too.

Also, my modifications during these runs included the following. These modifications didn't seem to affect the TD04 much, so you will probably see similar results with a non-modified car.
- bigger TMIC (SSAC cheapy)
- gutted up and down pipes
- custom 2.5 inch exhaust after downpipe, including a high flow cat and muffler.
Found here: http://forums.nasioc.com/forums/show...3#post23037153
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Old 07-09-2016, 03:58 PM   #14
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From: http://emanage.blogspot.com/2008/06/...f35-turbo.html

Quote:
Subaru WRX 2.5 with IHI vf35 turbo

The VF35 is one of my favourite turbo among so many turbos on the list. Reason being the massive head slamming torque this turbo can produce for this ride put this car perfectly suited for our sillypore road. Turbo spools up very strongly at 2500 and hit full boost at 3500 rpm on gear 1.
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Old 07-09-2016, 04:10 PM   #15
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IHI VF39
Aspect ratio 18
Turbine Impeller Dia ID 48mm/ OD 53mm, 11 blades
Compressor Impeller Dia 46.48mm/60mm, 6+6 blades
Equipped with compressor blade sealing
Wastegate port 25mm dia
WG Port open 77.7 kPa @ 2mm, 89.9 @ 4mm

VF39 wheel - smaller than the TD05 wheel
P18 housing - a lot smaller than MHI 7cm^2
P17 housing - first generation VF39's

Last edited by joek92; 07-09-2016 at 09:08 PM.
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Old 07-09-2016, 04:37 PM   #16
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Well this is interesting:

Quote:
I did a VF22 on my 2004 STI just to see if it would make more power than the VF39. What we got kinda shocked me and XX Tuning. The VF22 has almost ZERO lag on the STI's 2.5L. The VF22 made good torque and ok HP numbers but the lack of lag made the car go like crazy from low revs to 6000 RPM. The VF39 on the STI's 2.5L made less low end and midrange power but held more power up top. I know the compressor side of the VF22 is larger but maybe the fact that the VF39's turbine side was made for the 2.5L and not a 2.0L like the VF22 was made a difference.

I don't have my stock dyno sheet, but I dynoed 248.4 WHP and 252.8 WTQ on 93 octane.

...

I know that the WRX 2.5L and the STI 2.5L are a little different but the way they flow exhaust gas should be similar. If this holds true the VF30, VF34 and VF22 should all spool up very fast on the 2.5L and then fall flat shortly there after.

Defiantspaz

Last edited by joek92; 07-14-2016 at 11:05 PM.
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Old 07-09-2016, 09:13 PM   #17
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VF22 on EJ257 @ 20psi w/mods. Again, thanks to Defiantspaz

Here's the original thread: http://www.iwsti.com/forums/2-5-lite...upgrade-2.html


Quote:
When I bought my 04 STI it was one of the first ones in my area. Not much was known about the VF39 at that time. I picked up a VF22 at XX Tuning for next to nada just to see if it would wake up the 2.5L.

At the time everyone thought the VF22 was an upgrade to the VF39, well it is more of a side grade than an upgrade. All the VF22 does is more the powerband around a little, the peak numbers are almost the same. Also the VF22 has some lag when equipt to a 2.0L WRX but almost none when fitted to the 2.5L STI. Eveyone expected the VF22 to have more topend on the STI than the VF39 but it was the other way around. The VF22 spooled up insanely fast and made big torque numbers with only average power numbers.

I owned an 02 bugeye before the STI so I had the stage 3 Turbo XS kit for the 02 laying around the house. I decided to install the TXS TBE with high flow cat and 2.5" step down at the magnaflow muffle and TXS Type-H BOV on the STI. I sold everything else because the WRX UTEC wouldn't work with the STI's ECU and I thought the TMIC would be different also, I was wrong and kinda bent that I let the Hyperflow go.

So with the idea of going much bigger later I bought a set of PE850cc injectors and an STI UTEC and headed to XX for the install and tune.

The complete list of mods were:
VF22
PE850cc
Walbro 255LPH fuel pump
UTEC with map selector
XX Tuning header kit
TXS TBE w/ HF cat and 2.5" step down
Perrin short ram intake
TXS Type-H BOV

Here is the base line of the STI with the VF22, TXS TBE, XX Tuning header, Perrin SRI and TXS Type-H BOV with the factory ECU and stock fuel system.



This dyno plot is auto-scaled so it looks kinda funny. The WHP and WTQ don't cross at 5250 like a normal print out would.

After installing the Walbro, PE850cc and the UTEC Tony tuned the car for 20 PSI.



Again this is an auto-scaled plot but you can see how the car made torque very quickly with the VF22. The VF22 just didn't move enough air to carry the power higher into the rev band. I know that the tuning for our cars has come along way and the UTEC was the only EM that was avalible at the time I did this setup. I am sure that Cobb AP could have gotten more out of this setup that the UTEC and the step dowm and cat in the exhaust hurt my power also.

I can say that the car would just spin the tires in 1st gear and leave posi patchs when you shift into 2cnd under full throttle. For street use this setup was really responsive. Power was right there in any gear. The short coming was the lack of topend power.

Too many times I would go racing with friend to kill then to the 1/8th mile and just watch them tool on by at the end of the race, VERY frustrating. Cutting a .021 light and a 1.767 60' on a coldtrack in October, getting to the 1/8th in [email protected] and only running a [email protected] is preaty sad. Only gaining 19.76 MPH over the last half of the 1/4 mile sucked. I was always told that all cars are fast at the end of the 1/4 mile, being fast for the first 1/8th is the hard part. Again it seemed that my STI was the oposite of what was expected.

Last edited by joek92; 07-14-2016 at 11:04 PM.
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Old 07-10-2016, 03:13 PM   #18
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Quote:
Originally Posted by joek92 View Post
[*]Real anti-lag (turbine damage, expense, can a mere mortal even get it?)[*]Ignition anti-lag (want to try this)[*]Shorter gears (expensive, install time)
Ignition anti-lag should be considered real anti-lag. It is what is used on 99% of turbocharged rally cars.

When you say 'real' anti-lag, I assume you are talking about the secondary combustion chamber FHI/STI uses on top-level competition cars. While this is possible if you want to do some serious R&D, it is quite literally 'rocket science' and requires some fairly sophisticated control.

Other manufacturers had their own way of evolving the ALS design - Ford (I, believe) used a very large tank under the rear bumper, one year, to store excess boost pressure to aid in spooling off-throttle.

Shorter gears are really not that bad in terms of cost and install time, as long as you stick with OEM gear-set options.
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Old 07-10-2016, 04:04 PM   #19
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If you run the smallest diameter wheel tire combo you can, that would help as well. Near zero cost when you pair with your next tire swap. Changes your apparent final drive for free.

http://forums.nasioc.com/forums/show....php?t=1546987

16xtr on my 2.5L hybrid if you care to look http://forums.nasioc.com/forums/show....php?t=2733969
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Old 07-11-2016, 02:12 PM   #20
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Thanks for the input guys. Yep rocket is what I considered real als, I'll update. Hadn't looked into gears because I'd rather get 04 trans for 35:65 tq split and it already has close ratio.

Very good point on wheel & tire diameter, I'll add it to the list.

Thanks for the link. It looks similar to my current setup on 18 psi. However it's probably more responsive with ball bearings.

Phatron said it would spool faster on 20 psi but I don't really want to go there.
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Old 07-11-2016, 02:29 PM   #21
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I've been really happy with two of my Phatron tunes.
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Old 07-11-2016, 05:14 PM   #22
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Quote:
Originally Posted by monkeyposeur View Post
I've been really happy with two of my Phatron tunes.
Me too! I just bought the wrong turbo. I've read 18 psi is max safe/reliable on stock internals.

Last edited by joek92; 07-15-2016 at 12:57 PM.
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Old 07-11-2016, 11:26 PM   #23
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I was just looking at my "stage 2" dyno graph from my '13 Sti and comparing it to my initial tune dyno on my gtx3576r and noticed I made more tq on the Gtx3576r than I did on the stock turbo at its peak tq rpm for the stocker (3750 rpm).

I don't know if that sentence makes sense. I read it 3 times and it sounds confusing unless you already know what I am talking about.
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Old 07-13-2016, 02:25 PM   #24
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Not bad! What psi?
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Old 07-13-2016, 02:47 PM   #25
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This was a very loose tune. It has been corrected since and I have a much nicer and earlier build of power. I just can't seem to find the graph.

Anyways. Here is the initial. The latest massaging of the ecu has a much smoother hit of power because it starts earlier.

This is 31 or 32 psi I think...
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