Tomei Adjustable Fuel Pressure Regulator

[GOJ1RA]

Hey,

I've just ordered a Tomei fuel pressure reg, and noticed I shanked it. I've ordered the type L which is for high boost setups.

Here are the specs:

I've got an R32 GTR, HKS GTSS's, poncams, 700cc injectors, HKS Fuel pump, HKS turbo back. Can I still use the type L for 18-22psi?

Or should I cut it away and get the type S?

[Jazzadub]

You should be OK. It will try and maintain pressure at X+manifold pressure, so a larger valve will need to be slightly more closed than a smaller valve at the same pressure.

If you are really worried borrow a fuel pressure sensor and hook it up to the regular before starting the car. You will quickly see if it is holding the correct pressure at idle - which is when the regulator is doing the most work.

Hope that makes sense!

[GOJ1RA]

Yeah thanks for that. Think I'll just cut it away and go with the Type S. Wasted money and potential by the sounds of things.

[Jazzadub]

Also, I think high boost / low boost is misleading terminology to use for a fuel pressure regulator.

Remember the regulator is controlling the return from the rail, not the feed.

So, a regulator needs to be sized so it is large enough to return fuel from your fuel system at idle.

A larger fuel pump requires more fuel to be returned.

On boost, the regulator is returning less fuel, as more is going out the injectors.

Therefore, it follows that higher boost means less fuel to be returned.

In summary a fuel pressure regulator is not sized based on boost or power output, it is based on fuel flow rate at idle, which is when it will have to return 95% of the fuel flow back to the tank.

[Jazzadub]

double post

Edited February 28, 2014 by Jazzadub

[Jazzadub]

Yeah thanks for that. Think I'll just cut it away and go with the Type S. Wasted money and potential by the sounds of things.

If you are ever planning to go to a larger fuel pump then it is one thing you won't need to upgrade.

What is the max power rating of the HKS pump?

[Ben C34]

Nothing wrong with stock reg. How much power you chasing? Why change it?

[Jazzadub]

Nothing wrong with stock reg. How much power you chasing? Why change it?

That depends entirely on the pump setup, for example the stock regulator will not be able to control the pressure if you have 2x 044s behind it.

For the HKS pump on the other hand, yes it would likely flow enough just fine.

[Badgaz]

That depends entirely on the pump setup, for example the stock regulator will not be able to control the pressure if you have 2x 044s behind it.

For the HKS pump on the other hand, yes it would likely flow enough just fine.

won't that just mean it will return more fuel to the tank? doesn't the regulator open above 43.5psi?

[Piggaz]

That depends entirely on the pump setup, for example the stock regulator will not be able to control the pressure if you have 2x 044s behind it.

For the HKS pump on the other hand, yes it would likely flow enough just fine.

Yes it will. Seen it on more than one setup, both Nismo and factory units with duel 044's.

OP, you'll be fine although it's not needed.

[Jazzadub]

Yes it will. Seen it on more than one setup, both Nismo and factory units with duel 044's.

OP, you'll be fine although it's not needed.

Interesting to know!

Do you know if the dual 044 setup pressure lines were T'd together before feeding the rail, or was the rail dual entry centre return?

In my case each 044 has its own pressure line leading to each end of the rail. Which is why I went with a aftermarket FPR off the centre of the rail.

[Piggaz]

Off the centre IIRC.