ROUSH M90 INJECTOR UPGRADE

[Dom guerrero]

So I have a 2007 GT w the m90 blower. It was on the car when I bought it so I’m under the impression that i still have the 38# injectors that come with the kit. I upgraded my upper pulley and my tuner said my injectors are MAXED OUT like at 128% duty cycle. Anyway , I need bigger injectors but I was told the m90 kit uses a smaller type of injectors. I was going to order the gt500 52lb injectors because I was told they use a short injector as well , will those fit ?? And if not what fits ?

 

[skwerl]

I'm going back a decade and my memory is like swiss cheese, but I believe I used 52mm GT500 injectors after upgrading my blower on my M90 setup (taken off a 2010 Roush 427R). Back in the day there were a half dozen of us with that setup on this forum.

 

[Dom guerrero]

I'm going back a decade and my memory is like swiss cheese, but I believe I used 52mm GT500 injectors after upgrading my blower on my M90 setup (taken off a 2010 Roush 427R). Back in the day there were a half dozen of us with that setup on this forum.

Do you mean 52lb? Unfamiliar with ”52mm”

 

[07 Boss]

How much boost are you running? I would think 38# injectors would handle at least 500 hp.

 

[AHaze]

Something is weird here. First, there's no such thing as "128% duty cycle". How can an injector be open more than 100% of the time?
Second, if run to 100% duty cycle, the 39# injectors that came with the kit should feed 500 crank HP and AFAIK, an M90 won't push more than 500 HP worth of air.
While you may be approaching the limit of those injectors, if they're going static anywhere other than at your power peak, you have another problem somewhere.

 

[skwerl]

Actually I didn't upgrade injectors until I swapped head units for the TVS1900 from VMP. My more immediate issue was fuel pump duty cycles, which I resolved with a wiring upgrade from Greg Hazlett's company on this forum (cheap and easy). After the new head unit I had to upgrade to the GT500 fuel pumps.

 

[Dom guerrero]

Something is weird here. First, there's no such thing as "128% duty cycle". How can an injector be open more than 100% of the time?
Second, if run to 100% duty cycle, the 39# injectors that came with the kit should feed 500 crank HP and AFAIK, an M90 won't push more than 500 HP worth of air.
While you may be approaching the limit of those injectors, if they're going static anywhere other than at your power peak, you have another problem somewhere.

Then I’m not too sure. My tuner showed me one on one on his computer where my duty cycle was at 128%. I ordered a stronger pump. Not sure if it’ll help. Any thoughts ?

 

[Dom guerrero]

How much boost are you running? I would think 38# injectors would handle at least 500 hp.

Can’t say , boost gauge isn’t wired up yet

 

[skwerl]

Then I’m not too sure. My tuner showed me one on one on his computer where my duty cycle was at 128%. I ordered a stronger pump. Not sure if it’ll help. Any thoughts ?

Your PUMP is overworked. You need the wiring upgrade and possibly a better fuel pump. Start with the wiring upgrade for less than $30 and go from there.

 

[Midlife Crises]

I’m running the 52lb injectors that came with a stage 2 R2300TVS kit. You may well need to repair or upgrade your fuel pump/wiring. I’m using the GT500 dual pumps and wire upgrade to feed those injectors.

 

[Dom guerrero]

I’m running the 52lb injectors that came with a stage 2 R2300TVS kit. You may well need to repair or upgrade your fuel pump/wiring. I’m using the GT500 dual pumps and wire upgrade to feed those injectors.

View attachment 81297

Do you have a part number or link for those specific injectors? Idk which ones will fit with my m90 blower. I have a dw400 fuel pump I need to install. Rated for like 800 hp

 

[Dom guerrero]

Your PUMP is overworked. You need the wiring upgrade and possibly a better fuel pump. Start with the wiring upgrade for less than $30 and go from there.

I have a DW400 drop in pump I need to install that’s rated for like 800. Should that clear that “duty cycle” problem rhat my tuner was seeing

 

[skwerl]

I have a DW400 drop in pump I need to install that’s rated for like 800. Should that clear that “duty cycle” problem rhat my tuner was seeing

You're still going to need the wiring upgrade. It's so cheap it's a no-brainer.

 

[AHaze]

Then I’m not too sure. My tuner showed me one on one on his computer where my duty cycle was at 128%. I ordered a stronger pump. Not sure if it’ll help. Any thoughts ?

Not too sure what they were showing you but the duty cycle of anything is, by definition, limited to 100%. You would have to ask for clarification.
FWIW, my Vortech blown '05 GT is running fine with the supplied 39# injectors. You can turn up the fuel pressure target in the tune to make them flow a bit more as long as you have enough pump. The piggyback pump setup that came with the kit was running at 100% duty cycle and my WOT AFRs weren't consistent. I replaced it with a single 400 lph Walbro which got the duty cycle into the mid 80s. I can't remember what my injector duty cycle is at but Lito was more concerned that I upgrade the pump than the injectors.

 

[Dom guerrero]

You're still going to need the wiring upgrade. It's so cheap it's a no-brainer.

What is this wiring upgrade ? What does it do ? I have never heard of this before

 

[skwerl]

It replaces the wire to the fuel pump with a heavier gauge wire so it can carry more current. Reduces duty cycles by 15%.

 

[Dom guerrero]

It replaces the wire to the fuel pump with a heavier gauge wire so it can carry more current. Reduces duty cycles by 15%.

Any vids or forum links to this ?

 

[skwerl]

Just posts from 10 years ago on this forum. It's a $25-30 upgrade, takes 10 minutes.

 

[mpm_1]

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.

 

[nfrizell]

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.

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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