ROUSH M90 INJECTOR UPGRADE

Dom guerrero

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Copy of the fuel pump wiring upgrade install instructions here:

https://www.departmentofboost.com//...p_Wiring_Upgrade_Instalation_Instructions.pdf

These are instructions for the kit that had been available from S&H Performance. JeremyH here on the board was the contact for it.

I'm running the "VMP 500" kit on my 2010 Roush 427R with the little M90. This is the smallest pulley you can put on an M90 and it won't push more than 500 fwhp worth of air (under ideal, not heat soaked, hero run conditions) as noted above. I'm betting you have that same pulley. I am still running the original injectors as part of the Roush M90 package, no upgrade needed. I have both VMP and JDM tunes for this combo and neither have fuel system duty cycle issues on the stock GT fuel pump with the wiring upgrade.
would I get you're same results in installing this drop in pump that I have ? DW400 btw

Same here. Stock fuel system with m90 and small pulley. No issues. 8psi at sea-level density altitude. Have you replaced your fuel filter?
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no I haven't ever messed w the fuel filter in the year that I've had the car, is that something to that would cause ,my duty cycle to be so high ?
 
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07 Boss

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Actually you can run more than 100% duty cycle. If injectors are rated to 38# they can pump pump more than their "rated' duty cycle which is set at a certain fuel pressure and a max injector duration. You can run a higher pressure and/or a longer duration than is recommended and pump more fuel than the 38#/hr but will lead to premature injector failure. Injectors are rated for what they can pump over a sustained period of time, tens of thousands of miles, but they are capable of producing more than that but not for the required period of time.

But with that said I don't think it's a size issue. Either your injectors are not performing as they should or you have a fuel pressure/delivery issue.
 

Midlife Crises

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A couple things. Yes the fuel filter has a direct effect on the fuel pump duty cycle. The screen inside the fuel tank can affect it also.
I thought the DW300 was the direct replacement for the stock pump and the DW400 required some modification !
 

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