FPR psi setting???, need help! Options

[nate95]

ok, so does anybody know what PSI setting i should have my FPR set too? also, do i have to do any adjusting to the FMU or does it do its own thing? cause on top of it theres a little thing that tiwsts..

[NuclearHappineS]

which FMU did you buy ?

on most stock toyotas... the stock FPR is 42-45psi with the vacuum hose disconnected, 35-37psi with the vacuum connected (at idle)... but since different cars idle at different vacuums... you should set it to 42-45 with the hose off.

The FMU depends... is it a fixed rate fmu or is it a 'super FMU' a super fmu has a adjustable rising rate so yes you have to set it..but to do that you will pretty much need a dyno. If it's a regular fmu just let it be.

[nate95]

so for my turbo set up the FPR only needs to be at 45ish? im not using biger injectors so im relying on this to push more gas threw.

[NuclearHappineS]

it's a FPR or an FMU ?

if it's an FMU it will increase FPR with reference to boost...

so if you start out at 45psi, it may go to 90psi @ 7psi of boost (for example)
that's a rate of about 7:1 for your FMU. so it adds 7psi of fuel for 1 psi of boost (that's what a '7 to 1' FMU means).

So if you have 200cc injectors at 45psi at idle. At 7psi they will look like 282cc injectors (45% larger).

So in this case , if you have a cartech Super FMU or a vortech SFMU. You set the base fuel pressure to 45 psi, and you set the rate to 7:1
So you can now support 45% more hp at 7psi.
example:
So if you had 140hp stock and you expect to make 203hp @ 7psi
==> 7:1 will do.
if for example you expect 250hp @ 7psi, the a 7:1 rate will not be enough... so you'd have to adjust your rate up to around 14:1...

If you have for example a 2.5 litre stroker, instead of a stock 2.2... then you will expect to make 13% more hp at all rpms/boost levels... because of the displacement... in this case your 45psi base is not enough... you'll want it to be higher ...and the math works out to around 58psi.

So with the base pressure you're adjusting your idle fueling and your shifting the overall fuel curve up or down. With the 'rate' setting you are controlling how much fuel is added only when you are under boost.

Again, what kind of car is this (ST, GT?) what size turbo ? (T25,T4)? and what kind of FMU is it (Begi, cartech, vortech)? (FPR/FMU/SFMU)?

I can't be more specific till you are more specific.

If all you have is a FPR and you set it to 45psi at idle you will lean out under boost.

If all you have is a FPR and not an FMU...then that can work...but you'll need an SAFC/Emanage to reduce fuel at idle ...

so let me know the details and i can help you out more

from your info:
Garrett T3 Turbo
Fuel Management Unit
Fuel pressure regulator

what PSI ?
what FMU ?

[x_itchy_b_x]

hes 7afe. your not running larger injectors?
i suggest a wideband really bad, or a atleast a dyno wide a wideband.
i know you dont like hearing that, but without it your pretty much tuning in the dark.

[brianforster]

nucclearhappiness

This post has been edited by brianforster: Nov 10, 2006 - 11:25 AM

[nate95]

yes i have a T3/T4 hybrid turbo,, with a FPR and FMU, i dont know exactly what kind of FMU it is i got it from some one on here, its a 12:1 ratio though which is what i needed for my set up,, it came from a F-150 supercharger kit,. thats all i know.

[lagos]

so for my turbo set up the FPR only needs to be at 45ish? im not using biger injectors so im relying on this to push more gas threw.

thats a REALLY bad idea.

[x_itchy_b_x]

so for my turbo set up the FPR only needs to be at 45ish? im not using biger injectors so im relying on this to push more gas threw.

thats a REALLY bad idea.

agreed.

[nate95]

im not running very much psi though ,, im only runing 4-5 right now and i dont boost it up to that even very often

[NuclearHappineS]

ok now i know.

Is the car running right now or are you still installing parts ?

12:1 FMU @ 5psi of boost = +60psi fuel pressure
base pressure = 45psi => total of 105psi

how much does a walbro 255 flow at 105psi rail pressure ? (not much)

http://www.celicatech.com/gallery/files/2/4/walbro_chart.gif

so assuming the pump had the flow ... you'd only have 167-182hp worth of fuel... tops.
if you run 7psi on a t3/t4 on an ST you could see 200hp worth of air...which is too much for the fuel you have in your setup now.

my advice is 300cc injectors (good for 200hp) and a 7psi tune ...much safer than the setup you have now and much more reliable even though the boost and power are higher

This post has been edited by NuclearHappineS: Nov 10, 2006 - 2:07 PM

[lagos]

im not running very much psi though ,, im only runing 4-5 right now and i dont boost it up to that even very often

you realize that most turbos make somewhere in the ball park of 10hp per 1psi. so your making around 40-50hp more then stock, and you think that you dont need more fuel for that? all it takes is one lean run to blow your motor.

bottom line is, that if you dont get bigger injectors and some dyno time, dont expect your motor to last.