the hustler effect. smaller A/R on bigger turbo = better spool.
#1
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the hustler effect. smaller A/R on bigger turbo = better spool.
resources:
MX-5 Miata Forum - View Single Post - 1.8 Dyno GT30R
MX-5 Miata Forum - View Single Post - 1.8 Dyno GT30R
OK so the pictures are below. These are a GT30R and a GT35R.
In the first graph (two lines)
the blue is the GT35R with a .63 A/R turbine housing
the red is the GT30R with a .82 A/R turbine housing
Yes, the bigger turbo with smaller A/R turbine housing makes more power everywhere. and SPOOLS EARLIER.
This next graph is just a comparison of the GT30R with .63 housing and the same two above. It is green.
I think these graphs illustrate why I feel I'm awesome.
Discuss.
MX-5 Miata Forum - View Single Post - 1.8 Dyno GT30R
MX-5 Miata Forum - View Single Post - 1.8 Dyno GT30R
OK so the pictures are below. These are a GT30R and a GT35R.
In the first graph (two lines)
the blue is the GT35R with a .63 A/R turbine housing
the red is the GT30R with a .82 A/R turbine housing
Yes, the bigger turbo with smaller A/R turbine housing makes more power everywhere. and SPOOLS EARLIER.
This next graph is just a comparison of the GT30R with .63 housing and the same two above. It is green.
I think these graphs illustrate why I feel I'm awesome.
Discuss.
#3
Illustrates what you and I have discussed and agreed on many times; Hustler is just regurgitating bad information. Also, a chance to laugh at all the people who took his advice.
Timing on all miatas is very similar, 1.6 or 1.8, with similar turbos. It the beauty of the pent roof combustion chamber.
Timing on all miatas is very similar, 1.6 or 1.8, with similar turbos. It the beauty of the pent roof combustion chamber.
#7
Pretty damn cool. I'm actually thinking of going bigger next year or so and just making my car a toy/drag car. The more I drive the miata the more I realize I can't do what savington and the other track ****** are doing: I'm more into acceleration/drag racing than road racing. This is very interesting should I decide to go 35r in furure
#9
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first off, if low EGT was your goal, you'd have an EGT gauge.
beyond that, what's the point of low EGT? to keep your tailpipe cool?
Understand that EGT is, first and foremost, a function of what is happening inside the combustion chamber. Or more precisely, WHEN it's happening. the later you start your burn (relative to exhaust valve events), the higher your EGT goes. hence why retarding timing raises EGT and why lean mixtures (that burn slowly) raise EGT. If you dump fuel, you lower EGT by evaporative cooling (powercard?) like water injection does.
So next we wanna know how the A/R (flowyness) of the turbine housing affects EGT. If you chose it to lower EGT, why does it?
And since turbochargers work based on extracting energy from the exhaust gas (which is directly related to temperature difference across the turbine or EGT - Turbine Outlet Temp), why would you want to reduce the input energy available to the turbine?
Let's be honest here: once the hot gas is past the valves, it's not gonna hurt nothin unless your manifold is made of cheese with a low melting point.
#10
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Big A/R lowers EGTs because you can run more timing. Same reason you can delete a cat and run more timing - less restriction means more timing. I wouldn't dream of recommending a .86 housing on a street car, but on a track car? Built motors aren't cheap. There's a reason I run 100 octane and water on Hustler's 94 octane map. Anyone else doing MBT across the board on 94 (91?) octane?
By the way - did you notice the 30R with the .63 housing spooling SLOWER than the 35R with the .63 housing? Something's not right there.
By the way - did you notice the 30R with the .63 housing spooling SLOWER than the 35R with the .63 housing? Something's not right there.
#11
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first off, if low EGT was your goal, you'd have an EGT gauge.
beyond that, what's the point of low EGT? to keep your tailpipe cool?
Understand that EGT is, first and foremost, a function of what is happening inside the combustion chamber. Or more precisely, WHEN it's happening. the later you start your burn (relative to exhaust valve events), the higher your EGT goes. hence why retarding timing raises EGT and why lean mixtures (that burn slowly) raise EGT. If you dump fuel, you lower EGT by evaporative cooling (powercard?) like water injection does.
So next we wanna know how the A/R (flowyness) of the turbine housing affects EGT. If you chose it to lower EGT, why does it?
And since turbochargers work based on extracting energy from the exhaust gas (which is directly related to temperature difference across the turbine or EGT - Turbine Outlet Temp), why would you want to reduce the input energy available to the turbine?
Let's be honest here: once the hot gas is past the valves, it's not gonna hurt nothin unless your manifold is made of cheese with a low melting point.
Also, considering that my car made target boost (15psi) at sub-4000rpm...why do I want a smaller turbine again? I want no more power, no lower boost threshold, and no more load on the engine or turbo. I don't understand how restricting the exhaust is going to increase output without changing MAP.
Also, we still have not compared from turbo to turbo, just switching turbine housings, bitch.
#13
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Here's more food for thought though, for your argument. I'm way "ahead" of detonation. I was able to puy 4* advance past MBT...so I can either add boost to hit the detonation wall or lower the turbine AR. I chose to not make a $400 mistake because I'm happy with the car.
#15
Do the GT30 and GT35 have the same turbine wheel?
I don't think so, and therefore you can't say that the GT35 with 0.63 A/R is "flowier" than a GT30 with 0.86 A/R.
The reason the GT35 spools better may be a better speed match between turbine and compressor sections for the miata motor. IOW the GT30 with 0.86 is simply a sucky laggy turbo for the miata.
I don't think so, and therefore you can't say that the GT35 with 0.63 A/R is "flowier" than a GT30 with 0.86 A/R.
The reason the GT35 spools better may be a better speed match between turbine and compressor sections for the miata motor. IOW the GT30 with 0.86 is simply a sucky laggy turbo for the miata.
#16
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A shiny quarter to anyone who can answer this question (I dont have the data so I can't):
Which would spool sooner / make more power?
GT2860RS .86 turbine housing
GT2871R .86 housing
GT2871R .64 housing
GT2876R .64 housing
Which would spool sooner / make more power?
GT2860RS .86 turbine housing
GT2871R .86 housing
GT2871R .64 housing
GT2876R .64 housing