Justifying a 2860RS in my build
#1
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Can the Mt.net wizards help me out? I've opened this thread on m.net (T2560 vs. T2860RS flow @ 8/10psi - MX-5 Miata Forum).
I have not dyno'ed the car yet, I'm basically tuning off street pulls and being ---- with my collection of gauges...
I should be near my turbo's limits by now at 10psi correct?
Where would I need to be with 2860RS?
I thought I had reached a conclusion to the mess until the last guy posted what he did...
Just a quick reply should set me straight...
I have not dyno'ed the car yet, I'm basically tuning off street pulls and being ---- with my collection of gauges...
I should be near my turbo's limits by now at 10psi correct?
Where would I need to be with 2860RS?
I thought I had reached a conclusion to the mess until the last guy posted what he did...
Just a quick reply should set me straight...
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#13
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I'm betting a 2860 with a .64 a/r housing would be comparable with just a touch more top-end. It's the same turbo with a slightly larger turbine, hell my turbine is bigger and I'm on a 1.6L. But everything I've seen suggests a well built 300rwhp miata should use a 2560.
#16
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Oh, damn. I actually forgot I'm running a disgustingly high CR from the factory. No more boost for me without some new slugs and looser bottlecaps...
If I ever make the leap, which will be almost never now with these added costs, should I punch out the stroke or stick with the stock bore/stroke ratio for bigger boost?
If I ever make the leap, which will be almost never now with these added costs, should I punch out the stroke or stick with the stock bore/stroke ratio for bigger boost?
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Read my post over there, I still stand behind it. The "sweet spot" on the tater has a really small window, but when you're in it, its great. I like the big housing only if you have low static compression and can use the extra spark angle, if not then stick with the little housing.
However, after 250whp you're going to run into internal wastegate problems especially with the smaller housing. This forum has learned quickly that IWG and cast manifolds are a general failure. Its going to be even worse with a turbular manifold.
However, after 250whp you're going to run into internal wastegate problems especially with the smaller housing. This forum has learned quickly that IWG and cast manifolds are a general failure. Its going to be even worse with a turbular manifold.
#18
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How come nobody told me about the 2854r? Anyways, all this is irrelevant considering I'm running 11.5:1 CR with stock rods. I'm almost certain at 220hp, the motor is starting to frown.
You know, I had always assumed that everyone thinks the T2860RS, 2871, and 3071 were a lot bigger than they really are. But I guess coming from you, they really are. I just wanted more power for cheap and to break free from the M.net snails.
You know, I had always assumed that everyone thinks the T2860RS, 2871, and 3071 were a lot bigger than they really are. But I guess coming from you, they really are. I just wanted more power for cheap and to break free from the M.net snails.
#19
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Your sig says sr20 t2560....is that correct? sr20 T25s are very very small and not in the same league as even the 2560.
![](http://www.boostedmiata.com/random/t3_vs_t25_wheel.jpg)
the sr20 wheel is tiny compared to a 50 trim t3 wheel (which is the same exducer size as the 2560 and 2860). a sr20 t25
a non-BB GT2560. It's more closely comparable to a gt2554.
This is a sr20 t25 compressor map:
![](http://www.boostedmiata.com/random/t3_vs_t25_wheel.jpg)
the sr20 wheel is tiny compared to a 50 trim t3 wheel (which is the same exducer size as the 2560 and 2860). a sr20 t25
![Does Not Equal](https://www.miataturbo.net/images/smilies/notequal.gif)
This is a sr20 t25 compressor map:
![](http://www.boostedmiata.com/technical/t25_60trim_map.jpg)