Board logo

Fuel pressure reg
beaver34 - 30/8/11 at 06:00 PM

Hi all,

Does a turbo motor need a fuel pressure reg that rises with boost pressure, or can I just use my normal 3 bar one?

imp paul - 30/8/11 at 07:06 PM

yep you can use a rising rate reg it would be fine for the job it is down to your set up locost way is this lol http://www.racetep.com/begireg.html

[Edited on 30/8/11 by imp paul]

[Edited on 30/8/11 by imp paul]

Antnicuk - 30/8/11 at 08:02 PM

yes, you need a rising rate FPR with a boost source connected to it.

mark chandler - 30/8/11 at 08:10 PM

It depends how much boost you are running, if only a 8psi then no need to worry as long as you can flow enough fuel for full power.

If you are pushing large amounts of boos then the effective fuel pressure drops by the boosted pressure so you need to compensate.

Its worth measuring the fuel pressure anyway as this will be a reference of the regulator goes wrong in the future.

Point to note is that if you retain standard injectors then you can compensate by adding extra fuel pressure when under boost.

Regards Mark

[Edited on 30/8/11 by mark chandler]

matt_gsxr - 30/8/11 at 09:18 PM

I'm a bit confused by the question.

If this is EFI then don't most normal fuel pressure regulators are manifold referenced aren't they? So the pressure will rise with the boost pressure.

Or is the question about a "rising rate" fuel pressure regulator. In this case the fuel pressure increases with boost pressure but actually MORE than the increase in boost pressure.


It depends on the install and whether you have enough fuel flow. Also do you have the ability to map, or are you relying on the extra fuel pressure to supply the extra fuel. You probably know all this though.

Matt

beaver34 - 30/8/11 at 09:19 PM

quote:
Originally posted by Antnicuk
yes, you need a rising rate FPR with a boost source connected to it.


can you not just map more fuel in under boost? or is it just easier for the mapper to do it with rising rate?

matt_gsxr - 30/8/11 at 09:38 PM

quote:
Originally posted by beaver34
quote:
Originally posted by Antnicuk
yes, you need a rising rate FPR with a boost source connected to it.


can you not just map more fuel in under boost? or is it just easier for the mapper to do it with rising rate?


You can definitely just map around it, and it works fine. You can do this with a manifold pressure referenced regulator, or even if you don't connect up the reference (as long as you aren't running too much boost, as Mark Chandler says).

A rise rate regulator does have an advantage. It comes down to fuel injector sizing, as you can get away with smaller fuel injectors if the pressure is high (when you need the fuel), the benefit of small injectors is that you can get a better idle (which can be a problem with massive injectors).

Matt

beaver34 - 30/8/11 at 09:42 PM

thank, i do have a reg ill post a pic tomorrow it has vac port on the top, ill be running at least 12.5 psi thats what springs in the external wastgate, its either a 3 or 3.5 bar reg that i used to run my n/a engine on will be running astra vxr injectors which i believe to be around 440cc