Ok I bought a 2011 LML and going to put on a FASS titanium lift pump with some EFI live tuning. I'm only going to do maybe 110hp tune since truck is stock so my question is the pump I found is a 250 gph pump so is too much fuel bad? And I found a new FASS titanium pump 250 gph, with the sump kit for $660 is that a good deal?
Will too much fuel hurt?
- Thread starter pavetim
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I wouldn't recommend going overkill on the pump with a daily driver.
At idle and part throttle most of the fuel is being returned to the tank, the more the fuel is cycled the more it goes through the hot lift and injection pumps. Hotter fuel means less lubricity and poorer atomization the hotter the fuel pump runs the shorter the life span.
A 150 will feed even the big stroker cp3's no problem, so if you decide to go further a 150 will likely still be enough.
My airdog 165 4g keeps up with my dual pumps during 950hp track passes and it's quiet as can be, if noise is a concern that's what I recommend.
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At idle and part throttle most of the fuel is being returned to the tank, the more the fuel is cycled the more it goes through the hot lift and injection pumps. Hotter fuel means less lubricity and poorer atomization the hotter the fuel pump runs the shorter the life span.
A 150 will feed even the big stroker cp3's no problem, so if you decide to go further a 150 will likely still be enough.
My airdog 165 4g keeps up with my dual pumps during 950hp track passes and it's quiet as can be, if noise is a concern that's what I recommend.
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There are definitely differences. Fass has a better track record, but the airdog 4g is by far the best lift pump I've ever had. I've had fass, fuelab, and a few other homebrew setups.
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the LML has no fuel cooler and making the pump return alot of fuel after being pressurized and moved around generates heat. it wont cause the injectors/cp4 to return more fuel but the lift pump will return more. is it enough to make fuel temps high? couldnt say but on a low tank with it running, id bet you see a difference for no lift pump and a lift pump
id get a FASS 150 and call it done
id get a FASS 150 and call it done
Even though the fass has its own return there will still be more fuel returning from the cp4, which is actually good for the cp4, unless the fuel gets heat soaked in which case it won't cool the cp4 much.
Idk if anyone has monitored fuel Temps, but above 140 degrees the fuel starts to lose its lubricity, at which point I would add a fuel cooler because the cp4 needs as much lubrication as it can get.
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Idk if anyone has monitored fuel Temps, but above 140 degrees the fuel starts to lose its lubricity, at which point I would add a fuel cooler because the cp4 needs as much lubrication as it can get.
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what added fuel may be returned from the CP4 wont be pressurized from it where the majority of the heat is made. it would only get the added heat from the engine radiant heat.
Well ill tell you right now, every truck in arizona currently that is driving on the road is pushing fuel temps well above 140*. i run a B&M cooler with 1000cfm fan on it and will see 140-150* unloaded in the summer with a full tank and cooler on the truck . without it, 170-180* is the norm. you start pulling hills with a load and your seeing 220* or more without a better than stock cooler.
if fuel temp was that big of factor on the CP4, we would have seen a good cooler on these new trucks. maybe we will see one on the newer ones coming.
Agreed it's radiant heat, not heat from pressurization.
I'm with you, I have a large derale cooler for my fuel as well and if I get stuck in traffic on a hot day I've seen over 140.
I don't know to what degree it looses it's lubricity I just know the decline begins about 140.
Just like trans fluid may be optimal at 180 but 200 isn't going to ruin your trans anytime quick.
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Crazy. I never even thought about fuel temp. I read the old posts from Mike L. And some others tonight. For shits and giggles I checked mine on my lmm coming home tonight. 138degrees doing 80mph at about 13kpsi and it was about 85 degrees outside. When I got off the highway they came down a little on the short local drive home; pretty flat land. I was running very low on fuel and the light came on as I got home.
That's not bad with no fuel cooler and low fuel.
I'm sure most trucks see well over 140, I admit I'm only regurgitating what I was told.
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My fuel cooler is on the return side before it goes back to the tank.
I was checking fuel temps last night and after about an hour of sitting in traffic I had 135-140 going into the fuel cooler and 105-110 coming out. My fuel filter heads on my airdog were about 135.
I've noticed that once the pump gets above 140 degrees pressure starts dropping slightly
I was checking fuel temps last night and after about an hour of sitting in traffic I had 135-140 going into the fuel cooler and 105-110 coming out. My fuel filter heads on my airdog were about 135.
I've noticed that once the pump gets above 140 degrees pressure starts dropping slightly
same with mine.
there are two different ways of thinking. cool the big heat sink of a fuel tank or cool the fuel just before it enters the cp3/cp4. i dont know if one is really more beneficial over the other but having a good cooler has shown to increase mpg some. i saw a 1-2mpg increase when towing from it but i also have dual cp3's, AD165, and generate alot of heat in the engine area from towing with a large tow tune. my cooler has the air dog return going to it as well as all returning fuel from the engine so all fuel gets cooled before it goes in the tank.
The problem with cooling the fuel before it enters the cp3 is at 10-15 psi the fuel will be moving through the cooler quickly reducing the amount of cooling that happens.
On the return side there should be almost no pressure so in theory it's moving slower through the cooler, increasing the efficiency of the cooler.
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On the return side there should be almost no pressure so in theory it's moving slower through the cooler, increasing the efficiency of the cooler.
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