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WTF none of my images are working... Can anyone see them? I've posted 4, but I only see 1.
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When i put in my numbers, It tells me that i'm going to need 63psi to get my power goal. Maybe i'm doing it wrong.
According to garrett's website, here is their calculation. http://www.turbobygarrett.com/turbob...3/formula8.jpg Where: · MAPreq = Manifold Absolute Pressure (psia) required to meet the horsepower target · Wa = Airflowactual(lb/min) · R = Gas Constant = 639.6 · Tm = Intake Manifold Temperature (degrees F) · VE = Volumetric Efficiency · N = Engine speed (RPM) · Vd = engine displacement (Cubic Inches, convert from liters to CI by multiplying by 61.02, ex. 2.0 liters * 61.02 = 122 CI) If i do the math, that comes out to 48.1 total psi or 33.4 psi of boost. That doesnt seem quite right either. Pretty sure my shit's going to pop if i try and put 33psi to it with any turbo. Am i missing part of the equation here? |
No idea, but anyways, at 350whp it's perfect/maxed. Anything more it goes to shit fast.
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i only see one.
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Originally Posted by wes65
(Post 370776)
When i put in my numbers, It tells me that i'm going to need 63psi to get my power goal. Maybe i'm doing it wrong.
According to garrett's website, here is their calculation. http://www.turbobygarrett.com/turbob...3/formula8.jpg Where: · MAPreq = Manifold Absolute Pressure (psia) required to meet the horsepower target · Wa = Airflowactual(lb/min) · R = Gas Constant = 639.6 · Tm = Intake Manifold Temperature (degrees F) · VE = Volumetric Efficiency · N = Engine speed (RPM) · Vd = engine displacement (Cubic Inches, convert from liters to CI by multiplying by 61.02, ex. 2.0 liters * 61.02 = 122 CI) If i do the math, that comes out to 48.1 total psi or 33.4 psi of boost. That doesnt seem quite right either. Pretty sure my shit's going to pop if i try and put 33psi to it with any turbo. Am i missing part of the equation here? Yeah, some of your numbers were wrong. I copied what I was running, (max power at 7500, full boost 4k, etc) and kept flywheel hp to 430 (357whp) and got this: (24.5 PSI Boost BTW) Squirrel Performance - Turbo Calculator Version 4 Turbo ain't big enough for 350whp Same turbo at 380fwhp/315whp http://www.squirrelpf.com/turbocalc/...&product_id=32 Bout all it's good for. |
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Originally Posted by patsmx5
(Post 370781)
Yeah, some of your numbers were wrong. I copied what I was running, (max power at 7500, full boost 4k, etc) and kept flywheel hp to 430 (357whp) and got this: (24.5 PSI Boost BTW)
Squirrel Performance - Turbo Calculator Version 4 Turbo ain't big enough for 350whp |
You're to the left of the surge line with the 2876. That won't work....You'd be running 28 PSI and surging a lot. And your original link up there had the 2860 selected, that's why I used it. :)
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Originally Posted by patsmx5
(Post 370788)
You're to the left of the surge line with the 2876. That won't work....You'd be running 28 PSI and surging a lot. And your original link up there had the 2860 selected, that's why I used it. :)
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At this point, I am at a bit of a loss. I mean, i could always go with a 16g. lol......
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There'ya go.
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I would like to go with a turbo that's easy to get ahold of. This is close. I'm still riding that surge line, however.
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Originally Posted by wes65
(Post 370802)
I would like to go with a turbo that's easy to get ahold of. This is close. I'm still riding that surge line, however.
Part of the "problem" is spool. If you build boost at low RPMs, there's low flow, and you surge. You could "fix" this problem with a shitty wastegate and manifold so that you didn't get full boost till say 4500 and say boost onset at 2500 (note they use a linear rise in boost, where in my experience, it's not linear, but exponential). |
Originally Posted by patsmx5
(Post 370806)
lol. Scroll down and select GT3271 with those numbers and have a look. If you could settle for 350whp, the GT3271 ain't bad.
Part of the "problem" is spool. If you build boost at low RPMs, there's low flow, and you surge. You could "fix" this problem with a shitty wastegate and manifold so that you didn't get full boost till say 4500 and say boost onset at 2500 (note they use a linear rise in boost, where in my experience, it's not linear, but exponential).
Originally Posted by JKav
(Post 370779)
You've never seen a failed thrust bearing?
Race cars that don't use anti-surge valves get their turbos rebuilt every other race. Or so. ZX, the 2871 sans ported shroud will surge on a 2.0-liter WRX, so I fully expect it to surge on your 1.8. |
Looks like newbsauce is using this turbo. 4300ish for full spool. Not terrible.
https://www.miataturbo.net/forum/t26984/ |
the 2876 wont spool as early as your simulation suggests unless you're running VVT for high and low end.
Here's roughly how it does on a non vvt optimized setup: http://y8spec.com/dyno/turbospool.gif that said, maybe we can swap your 2860 for my 2876 (chra + comp hsg) and play around :) |
Originally Posted by y8s
(Post 370895)
the 2876 wont spool as early as your simulation suggests unless you're running VVT for high and low end.
Here's roughly how it does on a non vvt optimized setup: http://y8spec.com/dyno/turbospool.gif that said, maybe we can swap your 2860 for my 2876 (chra + comp hsg) and play around :) |
Originally Posted by wes65
(Post 370898)
Interesting. Do you have any problems with the turbo surging as you spool?
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