Ok Ive had my car setup at 40lbs on my rising rate fpr on stock injectors. After doing some math by bumping it up to 55lbs it would effectivly push the 550s to about 640cc and the 850s right at 1000cc That would be enough fuel to push a little bit more boost. Im curious is it safe to run 55lbs on the stock fuel system? I have had my injectors cleaned and flowtested by rc so im not worrying about those.. Im just curious if running that much extra pressure would cause leaks..

Matt

 

I would worry about your fuel pump crapping out. Even at 15 psi, you are going to pushing your fuel pump to 70 psi, at which point most fuel pumps are crying "uncle".

Are you telling us that you are still running the stock injectors with a T-78?

 

Ive got a hks racing pump. Ive put so much money into building the actual car I never got to it. *car was a chasis when I bought it*

 

So I take it even with a nice fuel pump running the fuel pressure regulator any higher than 40psi its going to make the pump "cry uncle" ?

 

I'm not saying that it WILL (the HKS is a good pump), but that it may. All pumps will drop off in flow at higher pressures.

Check the flow rate of the big Apexi pump here, for example:

http://www.maxcooper.com/rx7/parts_i...exi_bnr32.html

How much boost are we talking here?

 

im just talking about running like 12-13lbs of boost. right now im at 9lbs.

 

at the most 1 bar...

 

you'll be fine. I've ran 60 psi static before with no problems.

 

Thanks jspecracer7

 

Remember you also have to account for line pressure drop. If I remember correctly Max Cooper's calculator lists it as 15psi. So 55 psi fuel pressure gradient+15psi of boost+15psi of fuel system pressure drop=85psi

My advice is use Max's calculator to figure out what you need the pump to do then look at pump dyno charts. From what I remember from doing these caculations for my own car I think 55psi will put you beyond the capacity of the nippo, cosmo, and walbro pumps.

 

****. I forgot to mention that I ran 60 psi static fuel pressure with TWO walboro pumps. Carlisi reminded me about the limits of single pumps

 

Hi guys.
Who can help me. I m building my FD for some drag passes.
i would like to tell you first my mods :
stock moter with 2mm seals
stock turbos without problems with k+n filters
greedy fmic
koyo rad
hks twin power
magnecor i6 bit wires
3 inch full ex
sard fuel pump 280lt/h in tank
sard f/p regul
apexi pfc
My problem is : how many psi is correct to run my sard fp regulator ? My intention is to run 1.1bar first turbo - 1.0 bar both turbos !
Thanks.

 

You would need to run higher fuel pressure than stock. I would go with 3.5 kilos +

 

Who much run ( in psi ) the stock fpr ?

 

40 psi

 

i forget it to tell you that :
550cc - 1300cc inj .

 

so ..with the new fpr how many psi i must run ?
thanks.

 

as i saw from ccarlisi page ... its good to run 45 psi on my fpr .
is that correct or not ?