Dear All,

I've just purchased an adjustable fuel pressure regulator.

I'm curious though, what would be the optimal fuel pressure for a 1993 NA6? Mostly stock cept for K&N cone filter, some plugs and wires, and a free flow exhaust.

Also, I'm not very sure I needed a fuel pressure regulator for a stock miata. Anyone can extol the virtues of having one? And anyone know the pressure that i should set?

 

The stock fuel pressure regulator on the end of your fuel rail is all you need for a non FI car.

 

yeah, the Miata runs rich from the factory, so you are fine with those minor mods.

 

well i am gonna slightly dissagree if you lower the pressure a smidge you will lean out the mix and make more power the way you are i would try 37 psi and work out from there, depending on how it feels. Our motors run almost 10-1 in NA form and could benefit quite abit from leaining out up top for more powaah. So just monkeyh with it abit. And BTW a guage onthe return is useless you need one on the feed to tell what the atual pressure is. GL man

 

unless you remove the oem fpr, you arent going to see under 50psi at WOT

 

I've removed the oem FPR.
Lean it out at the high rpms?
how low a pressure are we talking about here?

 

Another quick question, does having too high a fuel pressure result in higher operating temperatures. I boosted the fuel pressure up to 35psi and i realised that my car was running at around 103 deg celcius instead of the normal 93....this is at a constant speed of 100kmh
turning it back down to 30 resulted in 93 deg again.
I'm running about 16deg of timing...

 

well the leaner mix willl make for a more complete burn but cylinder pressures etc will go up as well cuase you dont have the extra heat absorbtion of the fuel. 35 Psi might be a little low you might try 45 -40 and see how it does you mentioned nothing on performance with the different FP. Elaborate please.

 

As far as I can tell, there's no discernible difference in power between the 2 settings. The only difference I could tell was that the temperature seemed to rise when I increased the fuel pressure.
and the car seems to take longer to crank and start up.....

 

We were experimenting on the dyno one day when I was taking a baseline on my 1993 car prior to installing the turbo and we leaned out the mixture by tightening the clock spring on the mass air sensor about 7 clicks. We picked up 3-5 horsepower... and it didn't cost anything.

 

Thanks for the information.
I'm really getting worried here though, car seems to be running really hot..
Help