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Old 07-30-2016, 02:29 AM   #1
Scoobman20
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Default Scoobman20's 2015 WRX Custom Turbo Kit Development

Hello Everyone,

Unsatisfied with the turbo kit options out there for the 15-17 fa20 WRX's I thought I'd share some of my progress trying to develop my own. I would like to hear some feedback from people out there that may have a bit more experience and insight. I sort of a newb when it comes to power mods, but I do have some engineering skills to help.

I've been drawing inspiration from several other vendors, beginning with KillerB's header adapter. I first started by replicating the adapter in CAD. I was planning on 3D printing and using a local investment casting company, but have always been worried the adapter may cause excessive turbulence at the housing inlet. This will be my next simulation.



Next I was inspired by Grimmspeed's development work and so far have been very impressed by their results. I replicated their design in CAD. Next I created my own design with the goal to improve ground clearance. Below you will find the models and velocity vector maps with pressure maps. I have yet to do a transient simulation to simulate pulse flow, but you can see there is much less pressure drop in the Grimmspeed design. I suspect do to the merger at the housing inlets rather than before.'







I will continue modeling, but in the mean time I just purchased a new TIG welder I need to practice up on. Fun stuff so far!

Last edited by Scoobman20; 07-30-2016 at 02:42 AM. Reason: added sim for headers design 2
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Old 07-30-2016, 02:56 AM   #2
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Posting openly about trying to copy and reproduce vendors work is not something I think is going to fly, but what do I know.
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Old 07-30-2016, 03:02 AM   #3
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I have no intentions in reproducing and distributing any vendor parts. This is simply for gaining a better understanding between options out there and using them to develop something of my own.
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Old 07-30-2016, 03:15 AM   #4
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Quote:
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I have no intentions in reproducing and distributing any vendor parts. This is simply for gaining a better understanding between options out there and using them to develop something of my own.
Please please pleeeeeeease make a BorgWarner VNT turbo work with your car. PLEASE. omfg.
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Old 07-30-2016, 03:29 AM   #5
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I was actually looking at the new s200sx-e 7070 for the sake of price and performance. Where can I find more info on the VNT turbo?
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Old 07-30-2016, 03:59 AM   #6
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I was actually looking at the new s200sx-e 7070 for the sake of price and performance. Where can I find more info on the VNT turbo?
Google it. It's the one that Porsche uses in the 911 Turbo. In fact, they use 2... one for each 1.9L cylinder bank... which is very close to the 2.0L of the FA20... and is enough to produce peak boost from idle all the way to 6k+ RPM.

The downside? Mechanically complex, programming, etc. It would be a big and expensive project. But very very cool.

And I doubt you could use or would even need the type of header that Grimmspeed is developing... so you can make your own unique thing for it. Although I would study many different types of high-performing headers to arrive at your collector design.
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Old 07-30-2016, 11:36 AM   #7
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Hmmm I was aware of VGT, but this seems similar. It sounds like the actuator system for the nozzle may be a bit of a pain. I was considering a Garrett duel boost turbo but it is only made for diesels at the moment and I have read the EGT of gasoline engines can be potentially damaging. Although I could make it a rear located turbo.
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Old 07-30-2016, 01:12 PM   #8
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Quote:
Originally Posted by Scoobman20 View Post
Hmmm I was aware of VGT, but this seems similar. It sounds like the actuator system for the nozzle may be a bit of a pain. I was considering a Garrett duel boost turbo but it is only made for diesels at the moment and I have read the EGT of gasoline engines can be potentially damaging. Although I could make it a rear located turbo.
Yes, gasoline engines are less efficient which is why their exhaust temps are higher. Running 1800°F thru moving parts without breaking them, as it turns out, can be difficult. This is why twinscroll is so popular. Relatively broad torque curve with only 1 moving part plus wastegate. The only thing better for performance, and it would be significantly better particularly in the low end, would be the Porsche turbocharger.
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Old 07-31-2016, 05:49 PM   #9
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Keep in mind the 911 Turbo S is rated at 580hp, so each turbo is nominally sized for 290hp. So not a significant margin greater than the stock turbo.

Scoobman, what are you trying to achieve performance-wise and fitment wise?
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Old 08-01-2016, 09:11 PM   #10
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Originally Posted by spdracerut View Post
Keep in mind the 911 Turbo S is rated at 580hp, so each turbo is nominally sized for 290hp. So not a significant margin greater than the stock turbo.

Scoobman, what are you trying to achieve performance-wise and fitment wise?
That turbo gains about ~20-25% more power when hooked up with the right stage 2 package on a pro tune, so give or take ~350 whp.

But that's not the reason you get a VNT turbo. The reason you go with the VNT is to have peak boost at any RPM. There are some very good twinscroll turbos out there, but nothing can produce that kind of result!
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Old 07-31-2016, 07:34 PM   #11
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My goal is 375-400whp on pump gas. It has to have a universal flange like T4 or T3 to have the option of upgrading down the road. It would be great to have stock placement but I'm open if it means better performance.
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Old 08-01-2016, 11:50 PM   #12
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EFR 6758 be my choice.
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Old 08-02-2016, 07:39 AM   #13
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EFR 6758 be my choice.
ditto
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Old 08-02-2016, 11:23 AM   #14
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EFR 6758 be my choice.
Perfect turbo to keep stock spool (maybe better? Grimmspeed's 7163 testing showed only a 200 RPM delay in spool up) and push about 400 WHP on 93.

Alternatively, 7163 is probably a bit safer on the bearings/rods and gives way more top end.

Everyone loves Garrett, but I don't know how you beat a ceramic BB CHRA and a turbine wheel made of magic for street turbo. Yes it costs a lot, but IMO if you're going to be spending $1000's on a build, do it right.
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Old 08-02-2016, 02:40 PM   #15
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Originally Posted by playslikepage71 View Post
robably a bit safer on the bearings/rods and gives way more top end.

Everyone loves Garrett, but I don't know how you beat a ceramic BB CHRA and a turbine wheel made of magic for street turbo. Yes it costs a lot, but IMO if you're going to be spending $1000's on a build, do it right.
I also love the idea of keeping it IWG.
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Old 08-02-2016, 02:57 PM   #16
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I also love the idea of keeping it IWG.
Yeah that's true as well. I know I've seen some posts where people **** on IWG set-ups. I think people hate IWG because old IWG setups like on the VF turbos suck ass. That design is a holdover from when turbos were really only for diesel cars and performance people just borrowed them. The new designs are totally different, especially for twin scroll.

I might buy that EWG is better if your EWG setup is any more optimized looking than the IWG, but with the short header length, I haven't seen anyone come up with a great EWG design for this motor. It's always a sharp 90 degree turn, which to me is the same as an EWG.

Not to mention EWG is obnoxious for anything not a racecar, unless you put a stupid stiff spring in it.
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Old 08-03-2016, 01:49 AM   #17
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Quote:
Originally Posted by playslikepage71 View Post
Perfect turbo to keep stock spool (maybe better? Grimmspeed's 7163 testing showed only a 200 RPM delay in spool up) and push about 400 WHP on 93.

Alternatively, 7163 is probably a bit safer on the bearings/rods and gives way more top end.

Everyone loves Garrett, but I don't know how you beat a ceramic BB CHRA and a turbine wheel made of magic for street turbo. Yes it costs a lot, but IMO if you're going to be spending $1000's on a build, do it right.
I don't have a warm fuzzy feeling about any larger scale turbo on the stock bottom end, hence my thinking on the 6758 being close to stock in spool with a nice improvement in top end (on a built shortblock). 7163 is a great option as well, I just question how much fuel headroom we have on top end? I honestly don't know if we can max either out on pump without running out of fuel.

SQ
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Old 08-03-2016, 09:43 AM   #18
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So is the turbulence generated from the IWG re-entering the exhaust not a significant effect?
No, that definitely has some effect. It shouldn't really be prolific though, with a proper outlet/downpipe design. I would imagine the turbulence generated by poorly divided flow would be as bad or worse though. It would increase backpressure and chop up the exhaust pulses.

Honestly, without seeing A-B testing, I wouldn't say that its intuitive which is preferable.

The point still stands that EWG is ****ing obnoxious...its cool for a week but then you kinda get to a point where you're like "really car? that was not that much throttle. You didn't have to RRWWAOOOORORRRORORR the whole way past that old lady"

Quote:
Originally Posted by Nuked View Post
I don't have a warm fuzzy feeling about any larger scale turbo on the stock bottom end, hence my thinking on the 6758 being close to stock in spool with a nice improvement in top end (on a built shortblock). 7163 is a great option as well, I just question how much fuel headroom we have on top end? I honestly don't know if we can max either out on pump without running out of fuel.

SQ
In keeping with the spirit of a "street car" with minimal additional systems to worry about, you're right. I know Grimmspeed found the fueling limits on the 7163, so its possible the 6758 puts you in that same boat, but idk. A few are running around 400WHP on corn on stock fueling so maybe it can handle that on pump gas?

I wish we had more info on the compressor map for the stock turbo. For some reason I feel like the off the shelf 2259 isn't the same, considering how much people are wringing out of it.
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Old 08-03-2016, 01:23 AM   #19
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So is the turbulence generated from the IWG re-entering the exhaust not a significant effect?
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Old 04-15-2017, 01:29 PM   #20
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Need someone's stock headers for making a jig. Anyone interested in selling or renting theirs?
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Old 04-17-2017, 07:01 PM   #21
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Quote:
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Need someone's stock headers for making a jig. Anyone interested in selling or renting theirs?
Give me a month and change and I'll mail you mine. My KB kit is in the works now.
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Old 04-17-2017, 09:21 PM   #22
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Give me a month and change and I'll mail you mine. My KB kit is in the works now.


Thanks fl1p. Someone already volunteered theirs. I should start work on the jig here in a couple weeks!
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Old 04-15-2017, 02:30 PM   #23
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Ewgs are so obnoxious, getting a custom iwg routing done soon as I get the chance to.
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Old 04-15-2017, 03:10 PM   #24
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Good to know. I was considering dual ewgs straight to atmosphere. Maybe too much race car : )
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Old 04-17-2017, 09:39 PM   #25
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This thread reminded me to ask my old tuner for my stock headers
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