60 psi of fuel pressure on 450s

[NycDSM11]

yesterday i was reading one of the threads, someone stated that running 60 psi base fuel pressure on 450s would turn them into 550s. just wondering if this is even safe as a daily driver? who has tried this and would i need to tune for this mod. by the way would this suite me for around 18 psi on a 16g? i may sound like a noob but thanks in advanced.

 

[talondave]

yesterday i was reading one of the threads, someone stated that running 60 psi base fuel pressure on 450s would turn them into 550s. just wondering if this is even safe as a daily driver? who has tried this and would i need to tune for this mod. by the way would this suite me for around 18 psi on a 16g? i may sound like a noob but thanks in advanced.

You can do this, but you will need an AFC or something to adjust the fuel at idle and mid throddle.. It will be too rich in those locations..

 

[matthewdesigns]

The problem I see with that is that you will probably run out of pump at those pressures. If you ask the pump to supply 60psi, it's as if you are already running roughly 20psi of boost. Add 18psi to that, since your fpr is a 1:1 rising rate type, and the pump will be asked to supply fuel for a car running 78psi of boost. As fuel pressure increases, flow decreases. According to RRE's pump tests, at 73psi a hardwired Walbro 190 is only flowing half the volume it does at 43psi. Link.

 

[NycDSM11]

thank you mathewsdesign that helped a lot thank you for your reply.

 

[donniekak]

I have done it with a rewired wally 255, 450's, aeromotive regulator, and a custom eprom. The pump supplied plenty of fuel for 20 psi of boost and 60 psi base pressure.

 

[ziggo0]

I have done it with a rewired wally 255, 450's, aeromotive regulator, and a custom eprom. The pump supplied plenty of fuel for 20 psi of boost and 60 psi base pressure.

How were your AFR's?

 

[jeffo]

Your AFR's will be fine, as long as you don't exceed the volume of fuel that the fuelpump can supply at that total fuel pressure. At 60psi the 450's will be flowing 528cc, which is 127 liters/hour at 100% duty. At 80psi total fuel pressure a rewired 255 (non-HP) pump can still supply 175 liters/hour, so you have plenty of headroom. Even a non-rewired 255 High Pressure pump looks like it would cut it.