You know I was thinking about everyone that has blown motors.....and I have said this before....most of them were running over 7 psi.....FMU's over 7psi are ticking time bombs.....I never ever recommend using an FMU at anything over 7psi and all the motors that blew used FMU's(RRFPR) Terry's car used extra injectors and has been fine......stou ran 8 psi with 2 additional injectors daily and his motor was fine. the key people fuel....if you plan on ANYTHING over 7 psi get rid of the FMU before you try it.......I believe seriously this is the reason most of these motors blew....ask any honda guy who knows what he is talking about they will tell you a FMU over 7 psi is a tickign time bomb....your injectors start to go static...your fuel doesn't atomize as it should......your combustions don't happen as completly as they should thus detonation and soot on your rear bumper and then persistant dentonation and then BOOM!!!!! if you ahve anFMU turbo kit AKA EVERY kit out there....I highly recommend keeping your boost lower than 7 psi and 7 psi shoudl be your MAX. If you want to go high get better fuel managment. IE eManage, Link, SDS EFI, ERL MF2, haltech FC5 something that will control fuel better than a FMU.
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A thought
- Thread starter chdesign
- Start date
- :
- '07 Mazda3, True red
yes, what HE said!!!
no i didn't miss the no I was asking how hard you pushed yoru car when it was at 8 psi...also I believe you upped your fuel pressure adn made sure all was right before you drove it at 8 psi something I think others are not doing....tuning is key....I still don't like FMU's they blow motors.
OK first, I was agreeing with you incase you took it differently, which is why i run 5 PSI now.
I don't drive realy hard. I use boost often but I don't like going much above 4500 RPM and rarely ever of 5500 rpm. I aslo don't stay in boost for more the 10-15 seconds.
I had a few high speed runs against other cars but again not often. On the BEGI FPR there is a rate of gain screw and a base pressure guage. I have the base screw set at 48 PSI. That way when the FPR sees boost it throws the fuel to 48 PSI. The rate of gain screw is also all the way shut so that the car get the most fuel the system is capable of. I have watched it tap to 78 PSI a few times.
I don't drive realy hard. I use boost often but I don't like going much above 4500 RPM and rarely ever of 5500 rpm. I aslo don't stay in boost for more the 10-15 seconds.
I had a few high speed runs against other cars but again not often. On the BEGI FPR there is a rate of gain screw and a base pressure guage. I have the base screw set at 48 PSI. That way when the FPR sees boost it throws the fuel to 48 PSI. The rate of gain screw is also all the way shut so that the car get the most fuel the system is capable of. I have watched it tap to 78 PSI a few times.
chdesign said:You know I was thinking about everyone that has blown motors.....and I have said this before....most of them were running over 7 psi.....FMU's over 7psi are ticking time bombs.....I never ever recommend using an FMU at anything over 7psi and all the motors that blew used FMU's(RRFPR) Terry's car used extra injectors and has been fine......stou ran 8 psi with 2 additional injectors daily and his motor was fine. the key people fuel....if you plan on ANYTHING over 7 psi get rid of the FMU before you try it.......I believe seriously this is the reason most of these motors blew....ask any honda guy who knows what he is talking about they will tell you a FMU over 7 psi is a tickign time bomb....your injectors start to go static...your fuel doesn't atomize as it should......your combustions don't happen as completly as they should thus detonation and soot on your rear bumper and then persistant dentonation and then BOOM!!!!! if you ahve anFMU turbo kit AKA EVERY kit out there....I highly recommend keeping your boost lower than 7 psi and 7 psi shoudl be your MAX. If you want to go high get better fuel managment. IE eManage, Link, SDS EFI, ERL MF2, haltech FC5 something that will control fuel better than a FMU.
ch you sir are completely correct.
but....... theres always abut.............
an fmu if used properly can be an advantage for a system at any boost level. but again but, you need extra cc's
to solve alot of the problems on the board with fuel please try this alturnative .
it is not that expensive and will save your motor.
you have the ability to increase your injector size on the stock motor and allowing the ecu to " adjust " the pulsing up to 30%
stock p5's are 280cc upgrade to 310's for minimal performance and all out with 370's. this will work and you will idle fine. with a turbo charged application the higher cc injectors with the FMU will allow better atomization because of the higher pressures and allows the ability to completely burn the fuel.
high pressure helps in atomization. a healthy dose will help performance.
that way you can adjust your regulators to a lower pressure, helping the fuel pump(s) live a little longer and decrease duty cycle of the injectors for longer life.
that should help them live happily ever after.
now if we can work on this ignition problem next we will have conquered the world.
sorry CH just had to add my .02 cents.
I agree that the added fuel pressure will help TO A POINT but once that point is reached the injectors go static and your duty cycle goes all to hell......yes a FMU can be used safely in some situations....i'm just not a big fan of raise the fuel pressure to astrospheric numbers......I figure if you can't make it work on a stock fuel pressure then its not worth doing. Sorry after my first turbo kit and riding in many cars with FMU's then additional injectors I don't like FMU's anymore.
I think we all can conclude what you have...but the major question still remains..is there anything we can do to properly run forced induction without spending thousands for a standalone ECU? What is the most efficient and wallet-friendly thing to do here?
1st MP3 - You'd bog a little bit when you were off of boost. But the car would still probably run.
But YES, we can't run more than 200hp or so MAX on stock injectors, regardless of fuel pressure. The only safe way to run with an FMU right now is if we're running 12:1. Our stock fuel pressure is around 45. The FMU usually takes around 1psi before it "kicks in"...so consider the following...
4psi of boost - 1psi FMU "kick in" delay = 3psi of boost x 12 additional psi of fuel = 36 additional psi of fuel.
36psi (from above) + 45psi (stock) = 81psi of fuel.
81 G*DDAMN PSI OF FUEL! That's REALLY REALLY pushing it. So our stock fuel system can BARELY run 4psi safely. Even if you only ran a 10:1 FMU, you're talking 75psi of fuel pressure. That's still damn high.
When my kit goes in, I WILL NOT run more than the "3-5psi spring" on the wastegate on stock injectors/pump. If you do, you're just asking for trouble. Our fuel system can't provide the amount of fuel needed and all hell will break loose.
But YES, we can't run more than 200hp or so MAX on stock injectors, regardless of fuel pressure. The only safe way to run with an FMU right now is if we're running 12:1. Our stock fuel pressure is around 45. The FMU usually takes around 1psi before it "kicks in"...so consider the following...
4psi of boost - 1psi FMU "kick in" delay = 3psi of boost x 12 additional psi of fuel = 36 additional psi of fuel.
36psi (from above) + 45psi (stock) = 81psi of fuel.
81 G*DDAMN PSI OF FUEL! That's REALLY REALLY pushing it. So our stock fuel system can BARELY run 4psi safely. Even if you only ran a 10:1 FMU, you're talking 75psi of fuel pressure. That's still damn high.
When my kit goes in, I WILL NOT run more than the "3-5psi spring" on the wastegate on stock injectors/pump. If you do, you're just asking for trouble. Our fuel system can't provide the amount of fuel needed and all hell will break loose.
adding additional injectors like CH is saying is a graet idea. i have the same setup in mine but i also increased the rail injectors also because i am going to be running high HP numbers.
IMHO if you are looking to stay with a kit such as FMs or spoolin" and stay up to 8-9 psi ( around 200 hp max). your system will be just fine with an upgrade to 310 cc injectors and your rising rate reg. that will help pressures by reducing them approxamatly 1- 15 psi at WOT.
again i have used BEGI's regulator for adjustability so if you have a vortech you will have to swap out to a new disc.
the new injectors are about 100 dollars each and would be the cheapest way to ensure proper fuel at those boost levels ONLY.
no more than 9 psi.
IMHO if you are looking to stay with a kit such as FMs or spoolin" and stay up to 8-9 psi ( around 200 hp max). your system will be just fine with an upgrade to 310 cc injectors and your rising rate reg. that will help pressures by reducing them approxamatly 1- 15 psi at WOT.
again i have used BEGI's regulator for adjustability so if you have a vortech you will have to swap out to a new disc.
the new injectors are about 100 dollars each and would be the cheapest way to ensure proper fuel at those boost levels ONLY.
no more than 9 psi.
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