A thought
- Thread starter chdesign
- Start date
Kooldino said:
your stock fuel pressure will should be around 36. psi.
with the FMU it is set at around 43 -45 psi idle because of the turbo. there really isnt that much of a delay because it is directly controlled by manifold pressure thru the system. the injectors will have a pressure differential across them at any throttle position.
plus you have already made up the difference with the up in fuel pressure at idle.
by giong to slightly larger injectors like 310's (WHICH I BELIEVE IS ON THE MSP STOCK) your fuel pressyres will be LOWER.
deepcover6
Member
I got a Vortech FMU and the fuel calibration is 8:1 at the momment at 5psi. Just recently after I ran it hard not more then 10-15 secs I was cruising in the city and it bogged and would not start up again....The car would turn but not run. So could I have ruined my fuel pump due to the A/F ratio I was running. Could it be possible to do that?? Oh also the fuse that blew up is called INJ OR FIP 30A now, I am assuming it is the fuel pump fuse. What do you guys think???
from what i understand about the fmu from vrtech it has abase prssure already fixed so no adjustment like a begi.Kooldino said:
if stock fuel pressure ( according to the manual) is 36- 38 psi then yes. your base fuel pressure with the fmu at idle is set at 43- 48 psi.
duMb KeoLa
Member
i thought fmus only kick in when youre at bo0st, not at idle?? well, thats just what i thought, im probably wrong, let me know
Little Beavis
Member
- :
- 2001 MP3-T (#911)
Me too, me too. . .
If the Vortech increases fuel pressure at idle, it would explain why the car doesn't idle quite the same anymore. It doesn't idle bad, but I think it shakes more than it did prior to the turbo.
If we add even bigger injectors, won't we make it even richer at idle? Or does the ECU's cursed ability to pull fuel allow it to correct this and thus we idle fine? Curious I guess. Feel free to correct me as well, I'm only guessing.
If the Vortech increases fuel pressure at idle, it would explain why the car doesn't idle quite the same anymore. It doesn't idle bad, but I think it shakes more than it did prior to the turbo.
If we add even bigger injectors, won't we make it even richer at idle? Or does the ECU's cursed ability to pull fuel allow it to correct this and thus we idle fine? Curious I guess. Feel free to correct me as well, I'm only guessing.
in order to prove this theory get a fuel gauge and check actual pressure in the line at idle. im sure someone has done this right??
you wouldnt just take VORTECH's word on the base pressure. now compare that with stock pressure. wich is 36 psi at idle.
now with upgraded injectors the ecu "should" take any additional fuel away by decreasing the pulsing of the injectors, while the pressure stays the same thruout the system.
just on a side note here. i was talking with kooldino and he mentioned something interesting about how some of the guys here are NOT running auxilary in line pumps to help out the stock pumpss output. i was not aware of this . so CH has a good point then about fuel pressures bieng to high because your stock pumps can only handle about 6 psi MAX. i am talking about N/A pumps not the MSP'S.
so his conclusion about adding injectors is on key. also then there is a definate advantage to increasing one stage to 310's if you have the chance.
you wouldnt just take VORTECH's word on the base pressure. now compare that with stock pressure. wich is 36 psi at idle.
now with upgraded injectors the ecu "should" take any additional fuel away by decreasing the pulsing of the injectors, while the pressure stays the same thruout the system.
just on a side note here. i was talking with kooldino and he mentioned something interesting about how some of the guys here are NOT running auxilary in line pumps to help out the stock pumpss output. i was not aware of this . so CH has a good point then about fuel pressures bieng to high because your stock pumps can only handle about 6 psi MAX. i am talking about N/A pumps not the MSP'S.
so his conclusion about adding injectors is on key. also then there is a definate advantage to increasing one stage to 310's if you have the chance.
there have been some good points here but alot of you are failing to realize how FMU's work.....they do not add fuel pressure above your stock fuel pressure.....there is a formual to determine what PSI you are running but I cannot remember it at this time but basically if you run a 12:1 FMU at 4 lbs of boost it would create 48 psi of pressure now this is not 48 psi above the stock fuel pressure it only goes over the stock fuel pressure once it has passed it in its own ratio. when someone runs 6 psi on a 12:1 FMU they are now running at a 72 psi fuel pressure at 7 psi 84 psi of fuel pressure....our fuel pumps in the protege start to max out their flow capabliities at around 75 psi....then above that they do not really flow anymore fuel just generate more pressure. I'm running 2 440cc auxilary injectors which will yield a 175 hp capability of fueling....so basically I can have up to 297 hp at the crank with my 2 injectors in the charge piping and not have to touch my fuel pressure. FMU's kill i hate them adn will not use them again.....if I need more fuel once tuning is done then I will get some bigger injectors and a standalone later once i get forged internals but for right now 297 hp is exceeding what my stock block is capable of so it will suffice for me at this point.
Little Beavis
Member
- :
- 2001 MP3-T (#911)
Ahhh. . . thank you. . .I see the light. . .and it is bright. . .I must now bow my head to keep from going blind.
Thank you, it now makes sense.
Thank you, it now makes sense.
Norman@spool
Member
fmu's for anything above 7-8psi is suicide. Even with bigger injectors and tons of fuel. People are failing to remember its not all fuel. If you go over 7psi the advanced stock timing plays a big influence regarding detonation.
So the moral of the story is dont run over 8 psi without proper timing retard and fuel
So the moral of the story is dont run over 8 psi without proper timing retard and fuel
Norman@spool
Member
Lol Yeah I am not a big fan of typing (2 fingers
)
Thanks however I always lurk on here, just never really posted....thats Terry's Job
)Thanks however I always lurk on here, just never really posted....thats Terry's Job
Norman@spool
Member
(sssh) Dont give him any ideas
Yeah Terry pretty much handles the customer support and technical aspects so he has jurisdiction regarding the forums. I am just a lowley designer
Yeah Terry pretty much handles the customer support and technical aspects so he has jurisdiction regarding the forums. I am just a lowley designer
From my "HONDA" experience, you can run the stock ECU 10-12psi no prob. Here is the reason why you can even with a P5! (for those who don't believe me):
-upgrade the injectors
-upgrade the fuel line (steel braided -8 or -10)
-fuel rail a must. Not sure if they are avail. but build one
-a REAL adjustable fuel pressure regulator (SX Engineering)
-inline fuel pump
-MSD Digital DIS ignition system
-MSD Plug Wires
-Cam Gears
With just those mods. I am very sure you can run higher boost on the P5 (above 7psi). This has been PROVEN for a long time. The MSD will handle the ignition systems requirment. You would use the cam gears for the cam timing. With those (2) items you can now pump more fuel into it. Now the fuel can be burned. Yeah, additional injectors would be a good route for added saftey. 10-12 psi isn't that what it is thought to be. Try tuning for 15+ psi. It seems like everyone is making it more complicated than it really is. You don't need to drop $1500+ for a standalone fuel managment system just to run 10psi. I dont care if our cars have "NO TIMING CONTROL" it can be done. Just be safe from the begining. I havn't seen anyone with all these mods just yet.
I am not trying to start a war, just making a true argument!
-upgrade the injectors
-upgrade the fuel line (steel braided -8 or -10)
-fuel rail a must. Not sure if they are avail. but build one
-a REAL adjustable fuel pressure regulator (SX Engineering)
-inline fuel pump
-MSD Digital DIS ignition system
-MSD Plug Wires
-Cam Gears
With just those mods. I am very sure you can run higher boost on the P5 (above 7psi). This has been PROVEN for a long time. The MSD will handle the ignition systems requirment. You would use the cam gears for the cam timing. With those (2) items you can now pump more fuel into it. Now the fuel can be burned. Yeah, additional injectors would be a good route for added saftey. 10-12 psi isn't that what it is thought to be. Try tuning for 15+ psi. It seems like everyone is making it more complicated than it really is. You don't need to drop $1500+ for a standalone fuel managment system just to run 10psi. I dont care if our cars have "NO TIMING CONTROL" it can be done. Just be safe from the begining. I havn't seen anyone with all these mods just yet.
I am not trying to start a war, just making a true argument!
DooMer_MP3
Member
The only problem is that the MSD ignition system will NOT work on our cars. This has been discussed to death here. Our coils have integrated transistors and MSD says they can't make an aftermarket ignition for such a system.
Chris
Chris
why not get new coils?
I dont understand why somthing like this will not work
http://www.msdignition.com/np2002/np2002pd10.htm
it says its for a car with two coils, the P5 has two coils does it not?
I know what a transistor is, but not enough to know why it would prevent the MSD from not working, please elaborate
I dont understand why somthing like this will not work
http://www.msdignition.com/np2002/np2002pd10.htm
it says its for a car with two coils, the P5 has two coils does it not?
I know what a transistor is, but not enough to know why it would prevent the MSD from not working, please elaborate
You coudl change the coils but then the stock ECU would not be able to communicate with them so even with the DIS system from MSD it woudl do you no good without a signal from teh ECU for it to modify and the signal is made for our stock coils and our stock coils will not work with MSD systems.....I repeapt for the umpteen-billiononth time MSD SYSTEMS WILL NOT WORK IN OUR CARS PERIOD!!!!!! Do a freakin search and you will understand that.
