210whp from 0.9bar on T3/T4 turbo sound wrong? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 10-04-2010, 12:54 PM   #21
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depends. I like the 94 for various reasons.
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Old 10-04-2010, 01:30 PM   #22
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reasons such as?

I know the later ones had 2 or so more hp but also more weight, so its hard to say I know, would just like to know what other people think
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Old 10-04-2010, 01:36 PM   #23
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the 94 has:
ODB-I
9.0:1 CR
larger brakes
larger clutch
torsen diff
4.1 rear
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Old 10-04-2010, 08:40 PM   #24
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+1 for 94'

I wish I could do away with emissions equipment..
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Old 10-04-2010, 09:12 PM   #25
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Quote:
Originally Posted by Braineack View Post
the 94 has:
ODB-I
9.0:1 CR
larger brakes
larger clutch
torsen diff
4.1 rear
Thought it was 8.8:1 CR?
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Old 10-05-2010, 10:07 AM   #26
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i think it was still just 9.0:1, either way that's low, compared the the +9.5:1 of the rest of the blocks.
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Old 10-05-2010, 01:01 PM   #27
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Quote:
Originally Posted by Oscar View Post
Thought it was 8.8:1 CR?
My FSM says 9.0:1. I've seen 8.8 posted a bunch before, don't know where that number came from.
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Old 10-05-2010, 03:41 PM   #28
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9 CR sounds perfect for a turbo, well stronger internals would be good for large power but im not going for that if i did a job. I want something that can be totally reliable and used all the time with no worries. what is the compression ratio of the 1.6 then?
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Old 10-05-2010, 03:48 PM   #29
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Quote:
Originally Posted by ScottFW View Post
My FSM says 9.0:1. I've seen 8.8 posted a bunch before, don't know where that number came from.
oh yeah now i remember...i cant remember why, but that seems to be the myth

1.6L was 9.4:1, 9.0:1 in auto.
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Old 10-05-2010, 04:01 PM   #30
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Should be making closer to 300 hp with that sized turbo and ~12psi

I dont buy that the turbo is "too big" to make power. It certainly is of some of the larger T3/T4 turbos, and Im sure it doesnt start build serious boost until 4k+ rpm, but once its spooled it should make lots of power.
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Old 10-05-2010, 04:07 PM   #31
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A turbine operates via a pressure ratio and the turbine must make the compressor spin fast enough to produce the required airflow at the specified boost level.

Assuming this has a .63 A/R housing and a Stage III turbine wheel, it's plausible that this causes the turbo to operate way outside it's efficiency area [I'm just touching on the hotside here].

The pressure ratio before and after the turbine will be more equal due to the large size of the wheel and the space in between the blades, so there is less power being forced on it since the exhaust can pretty much pass straight through, while gradually gracing across the blades. This will also reduce the temps, increasing the density and slowly the exhaust velocity. yada yada yada.


this is just my hypothesis for the low power...

Last edited by Braineack; 10-05-2010 at 04:21 PM.
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Old 10-05-2010, 04:14 PM   #32
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The setup looks so good though!!

I guess some things just weren't done right to get the proper power. FM recommended to change the turbo, injectors and throw in a hydra nemesis, then it would be a beast! probably stress the engine a lot but hey!
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Old 10-05-2010, 04:16 PM   #33
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Quote:
Originally Posted by Braineack View Post
The turbine must make the compressor spin fast enough to produce the required airflow at the specified boost level.
So you think its just surging?

I dont agree with it, but I know that you can successful run way oversized turbos like that. Ive seen 35Rs on 1.6L engines, and a 35R is massive compared to that turbo.

Im much more inclined to think something else is happening. Like POS tuning.

Id buy it. Build it. Give it 20 psi.
Then the turbo will be fulfilling its capabilities a bit better.
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