Guys,
I'm sure its been brought up, but I couldnt find any reference to it.
What is the normal fuel pressure set at? I have the GTM fuel return system setup now.
I have the FP set at about 50psi right now. To high, to low, just right??

thanks guys..

 

base FP is around 45 with the vaccuum line disconnected. If you have a good throttle response at 50 then leave it alone. Theres some factors that make for various FP. Mine is usually at 59psi but thats with a built motor and a big cam etc....

 

Thanks

 

Also, what size injectors do you have and do you have a walbro pump

 

I have 440 injectors and a 255 Walbro.

 

I heard the HR's engines run higher FP from the factory than the DE's!!!

I'm running 1000cc injectors and HR built engine (stock cams)

So, will 50psi work fine or I need to bump it a little?


Sorry for the hijack my friend, but don't want to start a new one.

 

base FP is also determined by how much boost you are running.

Plenty of graphs showing that past 70psi, Walbro's really fall off with regards to flow. So if you are at 50psi base and run more than 20psi, you could be asking for trouble.

I personally run low 40s BFP. 50 is just fine

 

i'm running 40psi at idle.

factory is 3.5 bar= 50ish psi

 

im running haltech, and you set your injector flow rate. The flow rate is determined at a certain psi usually 43.5 as is in my case. So as long as you have enough fuel flow from your pump to handle it, set your regulator to 43.5 psi at 0 psi vacuum (line unhooked from reg). As most reg's are a 1:1 ratio, your injector flow rate will always be the same(as boost goes up, fuel pressure goes up to negate pressure difference). If you do not set the flow rate and pressure together, the flow rate entry on an ecu to tune by VE is pointless.

Ross

 

hmm, i'm not sure it's "pointless". I've made adjustments to my fuel pressure without changing flow in my haltech without any issues. Matter of fact we did it on the dyno at Injected also.

 

if you have to you have to i guess but then the VE calculations that the haltech makes won't be accurate. If the VE is "correct", higher pressure = richer than your target. I mean once it's tuned it doesn't matter, if the tuned VE compensates for the higher pressure, I'm just super OCD
I'm so freakin excited my tune at injected is in three weeks.. time is going by wayyy too slow!

ross

 

you are correct. I'm just not that picky. VE is never really perfect so fudging it a little is ok. He can always retune after pressure adjustments.


my tune is next weekend. I'm pumped to finally have a 600+hp car