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About a month ago I but bigger injectors in my truck before I had 150hp and I put in 225hp 7x.013. I also put I new turbo on it as well. I’ve noticed a pretty drop off in performance. Is there such thing as too big of injectors. I have a 2001 5.9L with a vp44 pump.
 

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SO vp44 or a hot rod vp44? Those injectors do sound quite large for a vp. I’ve always heard any injector over 200hp is in modified p-pump territory.
 

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SO vp44 or a hot rod vp44? Those injectors do sound quite large for a vp. I’ve always heard any injector over 200hp is in modified p-pump territory.
you need proper tuning as well.
I have an old edge box with the 5 stage tune.
SO vp44 or a hot rod vp44? Those injectors do sound quite large for a vp. I’ve always heard any injector over 200hp is in modified p-pump territory.
Just a vp44 with a tuner box
 

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he said old edge box with 5 stage tune. Which I assume is a comp box.
gotcha. did you double check to make sure that everything is still hooked up and connected after doing your injectors? Make sure the wiretap is still functioning.
 

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gotcha. did you double check to make sure that everything is still hooked up and connected after doing your injectors? Make sure the wiretap is still functioning.
Yeah it’s the old comp box with “hot tune” yes everyone with seems to be working fine can see/feel the difference when changing the levels. It smokes like crazy on 5 not great for street driving that’s for sure. But can the vp44 keep up with 225hp injectors. My thoughts are that the vp can’t keep up with the injectors.
 

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Not sure how much this will help but here goes. Industrial injection makes 6x0.18 sac injectors that they claim require their extreme vp44 to run. Their biggest race 6 injectors are 6x0.22 Sac which I believe might be comparable to yours I’m not sure, but they claim it requires a p-pump conversion to run them. So I would say your SO vp can’t keep up. Have you ever vapor locked the vp?
 

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Not sure how much this will help but here goes. Industrial injection makes 6x0.18 sac injectors that they claim require their extreme vp44 to run. Their biggest race 6 injectors are 6x0.22 Sac which I believe might be comparable to yours I’m not sure, but they claim it requires a p-pump conversion to run them. So I would say your SO vp can’t keep up. Have you ever vapor locked the vp?
Yeah yeah I have a couple of times before I learned that I have to let off slowly after full throttle. I’m guessing that’s a dead give away?
 

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Yeah yeah I have a couple of times before I learned that I have to let off slowly after full throttle. I’m guessing that’s a dead give away?
Well to be honest my truck does it with 85hp sticks so I would say it happens to any truck with bigger injectors. What size is your turbo? does it spool fine? does it reach the boost it should? Is the vp getting at least 10psi fuel pressure? If all that is fine and your comp box has good connections for everything I would look into getting the best hot rod vp44 you can get with some oversize connection tubes and 0.93 high pressure fuel lines if you haven’t already cause those injectors requires a ton of fuel and those lines and tubes just choke injectors that big
 

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Your VP cannot and will not keep up to those injectors. Stock VP is rated for like 100HP injectors. I would call the guys over at BlueChip Diesel and tell them what you have. The guy there will set you up with a Pump. I will say this. The VP44 is not cheap and If you really want to run Big injectors I would just go to P-pump swapping it.
 
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Your VP cannot and will not keep up to those injectors. Stock VP is rated for like 100HP injectors. I would call the guys over at BlueChip Diesel and tell them what you have. The guy there will set you up with a Pump. I will say this. The VP44 is not cheap and If you really want to run Big injectors I would just go to P-pump swapping it.

A healthly stock vp is good to well over 650hp in the majority of cases. hp limits on VP's are generally not even a lack of fuel during normal RPM's. the limit is actually because the VP ceases to be able to pump fuel at high RPMS due to the nature of a rotary pump. The vp doesn't care what injectors you have it just pumps fuel, the injectors are simply mechanical in nature and will flow as much fuel for a given duration as the vp supplies.

Even if the vp is weak it will still flow more fuel easier with the 7 x .013's than it did the 7 x .009's you had before. It's not like bigger holes in the injectors are going to result in less fuel being pumped from the vp.

there are soooooooo many guys running much bigger than 100's on their vp's with great results. the go to vp setup is 7 x .010's + a 62sxe or 6 x .013's + a 62 over 75 setup.


Yeah yeah I have a couple of times before I learned that I have to let off slowly after full throttle. I’m guessing that’s a dead give away?
OP
overfueling might be the issue if you don't have air to burn the 800 hp worth of fuel you have. If you have black smoke you do NOT have an issue due to the vp not flowing enough, period.

The vp44 air locking is not a sign of the vp not producing enough fuel, it is a sign of the ecm not able to control idle state after a hard pull. the ecm is calibrated for injectors that flow how ever much they do. when you double the fuel that the injectors can flow your idle state requires way less fuel. The ecm knee jerk reacts after pulling out of the throttle and you get a fueling command that swings high then overreacts and swings low resulting in too little fuel and air locking.


i ran 7 x .012's for a very long time on a cheapo run of the mill vp44 without a single issue.
 

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VP44 will do fine with 6x.013.... bigger injectors like 6x.016 are going to not be able to be used to their potential but will still run

Make sure you have good fuel supply and that your pump tap is good.

Data logging and custom tuning from the Adrenaline is helpful too.
 
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