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

appropriate fuel pressure?

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Old 10-03-02, 08:13 AM
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appropriate fuel pressure?

I run an apexi rx6 single with 550/1300 injectors.

Was wondering what you guys think the fuel pressure should be at WOT?

After reading a couple dozen posts from a search, I'm not getting an answer.

TIA
Fabian
Old 10-03-02, 08:39 AM
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Re: appropriate fuel pressure?

Originally posted by foko
I run an apexi rx6 single with 550/1300 injectors.

Was wondering what you guys think the fuel pressure should be at WOT?

After reading a couple dozen posts from a search, I'm not getting an answer.

TIA
Fabian
Not from personal experience, but from riding with Dragon, his rises from 3 kg/cm2 to 4 kg/cm2(appx. 29 psi to 43.5 psi)...at WOT.
Old 10-03-02, 09:14 AM
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29psi sounds low. I can't monitor my fuel pressure at the present while @ WOT since the gauge is in the engine bay... But my base fuel pressure is set to ~40psi. With a 1:1 rrfpr, you should get 1 additional psi of fuel pressure with each psi of boost above the base (idle) fuel pressure, hence the 1:1 (rrfpr = Rising Rate Fuel Pressure Regulator).

K
Old 10-03-02, 09:31 AM
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es
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Ideally what you want is about 75PSI MAX at the highest boost that you will ever run.

Some people run higher, but it taxes the pump.

And Nocab. No offense, but 1:1 isn't considered Rising Rate. That's a straight linear rate. Rising rate increases rail pressure exponentially compared to a linear rise in manifold pressure (boost). Therefore rising rate regulators can't be measured with a fixed ratio.
Old 10-03-02, 09:55 AM
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Oops, thanks for the correction es. No offense taken, been hanging around my turbo honda friends too much...they all DO use rrfpr's

I figured you could call any FPR that raised full pressure in any ratio to boost pressure a rising rate FPR.

Last edited by nocab72; 10-03-02 at 09:57 AM.
Old 10-03-02, 10:10 AM
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Originally posted by nocab72
Oops, thanks for the correction es. No offense taken, been hanging around my turbo honda friends too much...they all DO use rrfpr's

I figured you could call any FPR that raised full pressure in any ratio to boost pressure a rising rate FPR.
Yea, I figured you were just throwin' ricer slang...
J/K
Old 10-03-02, 10:50 AM
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Look @ my car...I am a ricer. hahaha

http://flathat.woodstream.net/RX7/Im...2/P1010042.JPG

K
Old 10-03-02, 10:51 AM
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I was just joking nocab. You have a sweet car!
Old 10-03-02, 11:16 AM
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I knew you were joking... hence the

I do like to roll up in my car, NOT pop the hood and let ppl think I'm a ricer... For some of the smarter ones the FMIC blows my cover... If it didn't have so many bent fins I could tell them it was fake.... hahaha

K
Old 10-03-02, 01:48 PM
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Originally posted by nocab72
29psi sounds low. I can't monitor my fuel pressure at the present while @ WOT since the gauge is in the engine bay... But my base fuel pressure is set to ~40psi. With a 1:1 rrfpr, you should get 1 additional psi of fuel pressure with each psi of boost above the base (idle) fuel pressure, hence the 1:1 (rrfpr = Rising Rate Fuel Pressure Regulator).

K
Your base fuel pressure is set w/o the vacuum line attached to the FPR, when you start the motor the vacuum at idle pulls the fuel pressure back down to a lower range. Next time your car is idling check out the fuel pressure, I bet it's not 40psi..

Matt
Old 10-03-02, 01:55 PM
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I bet it is. w/the car running it's 40psi. With the key turned and the car NOT running it's ~50psi.

K
Old 10-03-02, 03:28 PM
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Yep, I think the minimum Mazda spec is 36 psi for base rate.
Old 10-03-02, 03:30 PM
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Hmm.. well maybe that explains why my car isn't running right now!
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