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Old 09-16-2021, 09:03 PM   #51
K3rm1tth3fr0g
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Quote:
Originally Posted by PotatoFlakeSTi View Post
The .83 AR got here last week, going on in a week or two.
I still think that you'll have enough back pressure to benefit from this if you are going all out.
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Old 09-17-2021, 12:30 AM   #52
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Quote:
Originally Posted by PotatoFlakeSTi View Post
The .83 AR got here last week, going on in a week or two.
If you are going above 30 pounds of boost, you will probably see you nice big benefits. Under 25 pounds of boost I don’t think this would help as much, but it would still help. I’m thinking about doing it as well to try and get the last bit of horsepower I can out of my set up before going six speed. (Currently 400whp @15psi spring pressure)
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Old 09-17-2021, 06:42 AM   #53
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In general the closer to the turbine exit, the bigger the reduction in backpressure and larger gains. Putting the valve near the muffler will have much less impact than say a hood exit at the top of the downpipe.

Quote:
Originally Posted by PotatoFlakeSTi View Post
I really want to do this, but also don't want to waste a bunch of money if I'm not generating enough backpressure for this to help. Hmmm!
Google search exhaust diameter calculator. There's a bunch of stuff out there, even for turbo stuff. It will give you a rough idea. Say for example, you're near the bottleneck point for 3", you'd get much bigger gains than if you were in the flow sweet spot. Also keep in mind the gains scale with power output.

Quote:
Originally Posted by K3rm1tth3fr0g View Post
Aren't you running a G30-900 on a .61 housing?

I imagine there is certainly enough back pressure for this to be beneficial.
With that, you likely have way high manifold pressure and less post turbine pressure because of it.

A G30-900 is going to have a BIG compressor and small turbine. That's backwards from what EJs like. EJs typically perform best with large turbines on a big A/R, and smaller compressors. For that turbo I would run the biggest A/R turbine you can find, especially if you're running E85 or race fuel. Small and medium turbines will chose the potential of the turbo. If these engines were like a 1.6 B16A from a Civic the argument would be different, but the EJ25 is actually large for a 4-banger and the better the exhaust breathes through the ENTIRE system, the better they perform. You'll also have better EGTs and improved low load transient response with a larger A/R
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Old 10-28-2021, 07:37 PM   #54
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Doing it! With a 60mm Tial, since that's what was available.

Won't be able to do a direct before/after since fueling is being sorted, but excited anyway!
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Old 10-30-2021, 07:06 AM   #55
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Quote:
Originally Posted by PotatoFlakeSTi View Post
Doing it! With a 60mm Tial, since that's what was available.

Won't be able to do a direct before/after since fueling is being sorted, but excited anyway!
You can put two on your McLaren
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Old 10-30-2021, 12:41 PM   #56
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You can put two on your McLaren
There's an idea! Although with as short as the exhaust is already it might not make a difference.
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Old 11-06-2021, 11:18 AM   #57
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Off topic, but what is your McLaren set up? I've been consulting with a McLaren shop lately. Definitely a fun platform.
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Old 11-06-2021, 03:50 PM   #58
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Originally Posted by Homemade WRX View Post
Off topic, but what is your McLaren set up? I've been consulting with a McLaren shop lately. Definitely a fun platform.
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On topic: Shop couldn't (or didn't want to??) get the wastegate and talked me into a vacuum operated cutout instead, will slap up a picture from my phone in a moment.

It should open at 5psi. Which might be too early (loudness wise), but we'll see.

Edit:



Last edited by PotatoFlakeSTi; 11-06-2021 at 05:09 PM.
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Old 11-06-2021, 03:58 PM   #59
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Speaking of which, shop owner is confident a cutout is not needed and won't make a power difference, but I insisted.

Last edited by PotatoFlakeSTi; 11-06-2021 at 05:22 PM.
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Old 11-06-2021, 06:02 PM   #60
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Quote:
Originally Posted by KillerBMotorsport View Post
In general the closer to the turbine exit, the bigger the reduction in backpressure and larger gains. Putting the valve near the muffler will have much less impact than say a hood exit at the top of the downpipe.



Google search exhaust diameter calculator. There's a bunch of stuff out there, even for turbo stuff. It will give you a rough idea. Say for example, you're near the bottleneck point for 3", you'd get much bigger gains than if you were in the flow sweet spot. Also keep in mind the gains scale with power output.



With that, you likely have way high manifold pressure and less post turbine pressure because of it.

A G30-900 is going to have a BIG compressor and small turbine. That's backwards from what EJs like. EJs typically perform best with large turbines on a big A/R, and smaller compressors. For that turbo I would run the biggest A/R turbine you can find, especially if you're running E85 or race fuel. Small and medium turbines will chose the potential of the turbo. If these engines were like a 1.6 B16A from a Civic the argument would be different, but the EJ25 is actually large for a 4-banger and the better the exhaust breathes through the ENTIRE system, the better they perform. You'll also have better EGTs and improved low load transient response with a larger A/R
They came out with a G40-900, huge turbine. Give it a go!
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Old 11-06-2021, 10:20 PM   #61
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Quote:
Originally Posted by PotatoFlakeSTi View Post
Speaking of which, shop owner is confident a cutout is not needed and won't make a power difference, but I insisted.
Show him the after dyno
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Old 11-06-2021, 11:00 PM   #62
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Show him the after dyno
I have.
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Old 11-06-2021, 11:02 PM   #63
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Your after dyno
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Old 11-06-2021, 11:06 PM   #64
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Originally Posted by user1029 View Post
Your after dyno
With our high reading dyno I'd expect 725whp'ish after the Fuel pump upgrade and holding better, though that's just guesswork... So I guess we'll have to see if there's a 10% gain on that.

Our turbo's are pretty comparable though
Edit: turbine aside...
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Old 11-11-2021, 04:55 PM   #65
Homemade WRX
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Quote:
Originally Posted by PotatoFlakeSTi View Post
2020 720S Spider w/ Carbon Package
Custom 200CEL Downpipes by Fern Ochoa
Custom Titanium Exhaust by BlueChip here in Denver
Pure Turbos Turbo Inlets
Green Filters
M-Engineering tune for 91/93/100oct + rolling antilag.
Nice. I'm looking forward to seeing what the shop 12C and 720S cars do. Practically the same engine wise outside of exhaust manifolds, stroke, and heads.

Quote:
On topic: Shop couldn't (or didn't want to??) get the wastegate and talked me into a vacuum operated cutout instead, will slap up a picture from my phone in a moment.

It should open at 5psi. Which might be too early (loudness wise), but we'll see.

Edit:


I would have told you the same. EWG housings flow like crap as a valve. This is low pressure, so that butterfly valve will have much higher mass flow for the same pressure.
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Old 02-12-2024, 07:44 PM   #66
CEEBEE
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Any issues in the long term with this mod? Also quick question, any reason you chose the 69s turbine wheel when you upgraded to this turbo?
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Old 03-12-2024, 08:51 PM   #67
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This bypass still working flawlessly 4 years later went with the 69S wheel for more flow at the top end. The Xona turbo still working well with more than 50k miles on it pushing 40psi daily
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