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Old 02-14-2019, 09:59 AM   #26
linuxman51
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I probably have several in datalogs. It's a really fun car to drive, it made that number at around 23psi without leaning on it too hard
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Old 02-14-2019, 06:53 PM   #27
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Haha, hey guys. Have had my head buried in work for the past few days. Le Mans Hypercars need turbos too, just as much as Redblocks do!

There are two generations of GTX3576R - maybe that's where some confusion is being generated. I personally am a fan of the Gen1 because peak compressor efficiency was higher. Gen2 got a higher flowing compressor stage (wider map) with slightly lower peak efficiency. Turbine specs are the same between the two.

For 400whp (so ~475 bhp at the flywheel) and 2.3L, the GTX3071R is the biggest I'm currently going to recommend for you Stiggy. The engine just won't flow enough to make a 76mm compressor worth the tradeoffs of operating regime and surge margin (IMO). Even at 7000rpm, 14.7psi ambient, 95% volumetric efficiency, 0.5 lb/hp-hr BSFC, and 11.5 AFR, your corrected airflow looks like about 43 or 44 lb/min assuming 30psi manifold boost pressure. At 35psi the corrected flow rate goes up to 50 lb/min.

The VE, BSFC, and AFR values are complete guesses. If those are anywhere close to correct, and you see yourself running about 30 - 35psi, then the GTX3071R Gen1 would be just about right, or a GTX3067R (also Gen1 - there is no Gen2) would also be great and would spool faster in full load and transients.

If you could only get your hands on a Gen2 then the GTX3576R might actually be better. The shape of the Gen2 compressor map is such that a 3071 becomes less than ideal at the same operating point - it's more tailored to a larger engine requiring less boost to make the same power, like a typical V6.

For smaller (2.0L - 2.5L) more highly boosted 4-cylinders the Gen1 GTX is just better suited if you stay on the small side. If you can only get Gen2, then go one size larger to get the same steady state efficiency. That will also give you more headroom up top for higher flow, but now you're talking about increasing displacement and keeping the same turbo.
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Old 02-17-2019, 01:59 PM   #28
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Wow I guess I really cleared the room with that one.
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Old 02-17-2019, 03:15 PM   #29
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you just stunned me into silence. No it actually threw me for a bit of a loop and I spent most of the night yesterday looking at overlaid compressor maps.

https://forums.vwvortex.com/showthre...u-think/page22
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Old 02-17-2019, 08:46 PM   #30
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If we would have been at dinner together. It would have been the time to stop talking and dig in to the food. lol.
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Old Yesterday, 12:19 PM   #31
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Quote:
Originally Posted by Stiggy Pop View Post
you just stunned me into silence. No it actually threw me for a bit of a loop and I spent most of the night yesterday looking at overlaid compressor maps.

https://forums.vwvortex.com/showthre...u-think/page22
Nice to see the overlaid maps, and that guy does make logical conclusions about each comparison - except - he's saying "as you can see, turbo x will spool up ~500rpm sooner than turbo y..." a lot. That cannot simply be determined by looking at a compressor map alone. The compressor map gives you the lay of the land, but doesn't tell you where you'll be operating before full boost is reached. For that you need lots of data about the turbine, engine, and the rest of the system. Maybe he's making the "spoolup" estimates from experience, in which case...ok.

Keep in mind too there are different ways of measuring response. At full throttle there will be a threshold rpm at which you'll reach full boost. Unless your turbo is grossly oversized, this point is pretty much determined by steady-state performance of the turbine and compressor. Power balance between the two essentially. Compressor needs X kW to operate at the target boost/airflow, turbine is making Y kW right now at a particular engine speed....is Y > X? If so, you can run at target boost and the wastegate will be open. Is Y = X? If so, you will just barely be able to reach the target, wastegate will be closed. Is Y < X? If so, turbine isn't making enough power yet, wastegate is closed, and boost is below the target.

Then there's transient response - how quickly will the engine come up to full torque when you do a load step from part-load to full-load, for example cruising down the road and then suddenly stomping on the throttle to pass someone without downshifting, or maybe mid-corner throttle adjustments on a road course. In this case the response of the turbo is determined by compressor & turbine efficiency, bearing losses, and inertia of the rotor.

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If we would have been at dinner together. It would have been the time to stop talking and dig in to the food. lol.
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Old Yesterday, 12:23 PM   #32
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looking pretty hard at the 3576 and the 7670.

I also have read a bit on the S200sxe lineup.. they are a grand cheaper than an efr..
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Old Yesterday, 01:12 PM   #33
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The s257 sx-e looks badass. That's the turbo I want for roughly the same power. Sorry Duder, I just can't afford your hardware
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Old Yesterday, 01:31 PM   #34
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The s257 sx-e looks badass. That's the turbo I want for roughly the same power. Sorry Duder, I just can't afford your hardware
I don't get a bonus either way so it's all the same...
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Old Yesterday, 02:06 PM   #35
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Quote:
Originally Posted by Stiggy Pop View Post
looking pretty hard at the 3576 and the 7670.

I also have read a bit on the S200sxe lineup.. they are a grand cheaper than an efr..
I still have a lot to sort out with mine, but it seems like it'll be really nice. Spools quick, pulls hard, is quite cheap, and doesn't even need water lines.
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Old Yesterday, 04:33 PM   #36
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Quote:
Originally Posted by Harlard View Post
The s257 sx-e looks badass. That's the turbo I want for roughly the same power. Sorry Duder, I just can't afford your hardware
yeah that's a pretty attractive option. kinda a better version of the hx35
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Old Yesterday, 05:15 PM   #37
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It actually appears to be very similar performance-wise to a Gen1 GTX3576R, just from a cursory look at the compressor map and turbine sizing.
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Old Yesterday, 06:23 PM   #38
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Since your car run and drive, why not spend a little money to get the car on dyno and datalog it.

Use the data (HP and boost number) to plot on the compressor map, then choose a turbo?

You'll be surprise at what you find, I know I did.

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Old Yesterday, 10:06 PM   #39
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Quote:
Originally Posted by tryingbe View Post
Since your car run and drive, why not spend a little money to get the car on dyno and datalog it.

Use the data (HP and boost number) to plot on the compressor map, then choose a turbo?
Solid advice. What are the engine specs for the measured data plotted on that map?

By specs I mean displacement, head work, cam, fuel type, air/fuel ratio, intercooler type, charge plumbing diameter, exhaust diameter, and so on.
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Old Yesterday, 11:58 PM   #40
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Quote:
Originally Posted by Duder View Post
displacement
Dodge 2.2L, SOHC

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head work
Biggest valves that fits the head, with lots of port work. Big intake manifold


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cam
Stock 88 2.2 TBI roller camshaft.

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fuel type, air/fuel ratio
E52, between 12-10



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intercooler type
Treadstone TR82


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charge plumbing diameter
2.5 inch pre intercooler, 63mm aft intercooler.

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exhaust diameter
3 inch pipes all the way back. No cat.

Turbo is T04B V-trim compressor wheel, stag eIII turbine wheel, .63 a/r turbine housing, ATP ultimate wastegate



Last edited by tryingbe; Today at 12:20 AM..
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Old Today, 12:19 AM   #41
Duder
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Rad, thanks for posting all of that. Stiggy will have to decide how relevant it is to compare your data to his Redblock, but it's got to be in a similar ballpark.

To translate turbocharger sizing into modern Garrett nomenclature it would be something like a "GT3370." The old Stage3 T3 turbine wheel is 65mm on the inducer, and the T04B v-trim compressor is 70mm exducer. So that ratio is 1.08, and for comparison a GTX3576R has a compressor/turbine wheel diameter ratio of 1.12, and the 3071 is 1.18, 3067 is 1.12, and the G25-660 is a pretty large 1.25 but the modern wheels work in such a way that it's not as drastic as it seems.
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Old Today, 12:23 AM   #42
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I mapped out these just for fun





3576R


7670

Last edited by tryingbe; Today at 11:09 AM..
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Old Today, 09:47 AM   #43
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Quote:
Originally Posted by tryingbe View Post
Since your car run and drive, why not spend a little money to get the car on dyno and datalog it.


the car is actually not currently running, it's down for an overhaul and part of the script is the turbo swap. Realistically not going to put it all back together just to go do a dyno and take it all back apart. Good advice just not practical.
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Old Today, 10:52 AM   #44
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If I was shopping for a turbo, GT3071R would be out as there is very little head room for my 353whp engine.

It would be between EFR7670 and 3576R for me.
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Old Today, 10:58 AM   #45
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Quote:
Originally Posted by tryingbe View Post
If I was shopping for a turbo, GT3071R would be out as there is very little head room for my 353whp engine.

It would be between EFR7670 and 3576R for me.
Thanks, that seems to be where I'm narrowing in. Appreciate the input.

Hope I didn't seem too dismissive of your previous advice, but not something I think I can realistically pull off.
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Old Today, 11:11 AM   #46
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Quote:
Originally Posted by Stiggy Pop View Post
Hope I didn't seem too dismissive of your previous advice, but not something I think I can realistically pull off.
May I ask you why didn't you dyno it when you had it all running? It can provide very useful information and more importantly, bragging rights.
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Old Today, 11:26 AM   #47
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Because there are no dynos in Whatsitchoosits. Probably.
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Old Today, 11:42 AM   #48
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Quote:
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May I ask you why didn't you dyno it when you had it all running? It can provide very useful information and more importantly, bragging rights.
great question. It is not hard to find a place to strap the car down and offer me no help. It is hard to find a professional who was willing to work on a real tune on the car with the megasquirt setup, which is what I really wanted. Given that, I just never had a big motivation to run the car as I'm not a good enough tuner to really capitalize on it. So figured eh, street driven, street tuned, just keep jamming it. I also come up with some kind of big change every year so fell into the "well I don't want to dyno it until the new motor is in, then the new clutch, then the this..."

Part of my goals here is that I'll come out of storage with a few last things sorted and then go get a damn tune done finally. If I truly can't find a shop who wants to play with megasquirt I'll just keep doing what I'm doing for another year or so, then I'm going to ditch MS and move on to something I can have dealt with locally (this is in the long term plans for the car regardless)
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Old Today, 01:22 PM   #49
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I thought MS was very easy to tune on dyno. Get the a/f right, then add timing. Listen for knocks and if adding timing doesn't get you more HP, stop and back off a few degree. Goal is to give the engine what it wants.

If you need to find a local MS tuner, post here.
http://www.msextra.com/forums/viewforum.php?f=137
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