Single Turbo RX-7's Questions about all aspects of single turbo setups.

Boost falls off at high rpm.

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Old Mar 16, 2018 | 05:56 PM
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Boost falls off at high rpm.

So, setup is hybrid ht18s, stock ports, i/c, stiffer spring at wastegate and ported, Adaptronic ecu, MAC valve.
Pressure goal is around 14 psi.
1st and 2nd gear there is no possibility hit 14 psi. Boost is around 9.5-10 psi and as goes to redlines drops off..
3rd gear hit 14psi but again at high rpms falls off.
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Old Mar 16, 2018 | 09:23 PM
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Simple Answer: the turbo is too small and choking.
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Old Mar 16, 2018 | 11:05 PM
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Originally Posted by SirLaughsALot
Simple Answer: the turbo is too small and choking.
While very likely your turbine is too small, there is another possibility to explain your symptoms. What are your hot compression numbers?
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Old Mar 16, 2018 | 11:53 PM
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If compression is good enough to make boost in the midrange it will only be better at "high" engine speed for a stock port.

Mainly you don't have enough turbo, the ported gate may be contributing a bit too as emp will be rising.
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Old Mar 17, 2018 | 07:20 PM
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Originally Posted by Slides
If compression is good enough to make boost in the midrange it will only be better at "high" engine speed for a stock port.
Unless the engine is leaking compression, in which case your statement is completely false...

Last edited by cone_crushr; Mar 17, 2018 at 07:23 PM.
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Old Mar 17, 2018 | 08:30 PM
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if there is a failure mode you can clearly explain I'm not aware of I would love to learn about it.

please explain your reasoning so we can discuss it.

Last edited by Slides; Mar 17, 2018 at 09:07 PM.
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Old Mar 19, 2018 | 02:11 AM
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Originally Posted by cone_crushr
While very likely your turbine is too small, there is another possibility to explain your symptoms. What are your hot compression numbers?
7.0 kg/cm^2
7.3
7.1
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Old Mar 19, 2018 | 05:58 AM
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Nothing wrong with that.
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Old Mar 19, 2018 | 03:50 PM
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Originally Posted by mariosrotary
7.0 kg/cm^2
7.3
7.1
Are these values for the front or rear rotor?
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Old Mar 20, 2018 | 06:51 AM
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Originally Posted by cone_crushr
Unless the engine is leaking compression, in which case your statement is completely false...
Please educate me.
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Old Mar 20, 2018 | 08:04 AM
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I was thinking of doing something like this..
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Old Mar 20, 2018 | 03:03 PM
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I sure hope not. That's not a very efficient way of running an EWG. Just put it on the turbine housing when it's still a Twin Scroll "snail" portion".
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Old Mar 21, 2018 | 10:23 AM
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I know it's not the right way but i can't think something else instead of fabricate a new manifold.
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Old Mar 22, 2018 | 12:58 AM
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I just told you something else.
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