Fuel Rail Feed Back?
 

I know you will probably give me shit, but I thought i would try and ask you guys for some feed back becuase you mostly seem to be informed, experienced guys that will give me well reasoned answers.

When building a 250+bhp car do you prefer to:

A) use the stock fuel pressure reg mounted on the rail.
B) use an after market reg mounted on the rail.
C) use an after market reg mounted remotely with some hose off the rail.

If you answered A or B what is your preferred after market reg?

Thanks for your help!

Doug
(yes, I own G19 Engineering)

The regulator is more a a pump based decision. The stock regulator can have problems with higher flow pumps.

At that power, it is stock all the way for me.

With a higher flow pump (250lph, and more hp) I am a big fan of the Radium regulator that takes the Bosch inserts.

I'm in agreement with Ted. The baby Bosch regulator looks like a good solution for the lower flow aftermarket pumps.
At 250 stock all the way works great but that means NEW stock, not 20-year-old stock.
For that level I'd prefer either a new, built in Japan if possible, stock Mazda part (maybe Denso?) or one of the 190 LPH aftermarket pumps.


This thread helped me regarding FPR and aftermarket pumps
Kraken EFR 6758 with some FPR testing - Miata Turbo Forum - Boost cars, acquire cats.

If you're using big fuel you need a big regulator...

The good Aeromotive reg has a $165 price versus $145 for the set-up Ted mentioned.
I like Radium Engineering more than I like Aeromotive but the Aeromotive reg can handle huge flow levels that the baby Bosch cannot.
Radium also has a big fuel regulator at $200.

MPR, Multi-Port Regulator (radiumauto.com)

The difference between control of 250 lph and 1400 lph is $50. Both require remote mounting. One limits you.

Unfortunately, in today's aftermarket parts world, a "stock" pump will probably woefully under-perform (or under-last) what was put in these cars in the 90's. Under 200lph is required for the stock regulator, which works great on lightly boosted cars. Above 200lph works, but overwhelms the regulator at idle and you'll have to tune around it. I've done it, but it bugs me.

The big aeromotive regulator I mentioned in my thread linked above works great, that thread was mainly focusing on the 1:1 ratio function performance. I'm sure others would work too, but haven't had a chance to test them. I've installed all the Radium regulators except the bosch insert one, all have worked as advertised, although they've pretty much all been on naturally aspirated builds.

My real reason for going to an aftermarket rail and regulator was to get a decent 1/8npt fuel pressure sensor port. The 5/16 barbed fitting with an 1/8npt port in line just screams Spec Miata to me, and I can't even.

While I'm not a huge fan of some of Radium's products (lots of form over function), I will say they do a great job at packing a lot of stuff into a tiny space. That being said, I asked a few people about their rail mounted regulators on Miatas, and unless you have an NA8 or want to use S2's intake manifold, there just isn't a way to mount one on the rail cleanly, at least in my mind. But feel free to prove me wrong.