All Six Cooler Fuel 😎

[InlineDave87]

I was thinking about a conversation with another member about how the 300 has a tendency to ping at higher temps. I remembered Engine Masters did an episode where they tested fuel temp v power output and they did further tests more recent and i had to wonder if maybe a cooler fuel might help with pinging at higher temps as cooler fuel would burn slower. Thoughts?

 

[Kritas]

I watched that episode, and the transmission cooler that they used along with a fan interested me. It seemed like a cheap and practical way to lower fuel temps, and according to their data, it worked. I think it's worth a shot in the name of science.

 

[Frank]

I watched that episode, and the transmission cooler that they used along with a fan interested me. It seemed like a cheap and practical way to lower fuel temps, and according to their data, it worked. I think it's worth a shot in the name of science.

Agree 100%. The thing that's kept me from plumbing a gasoline trans cooler is where to put it. I saw too many ugly high speed wrecks in the trucking years. Can't bring myself to put gasoline in the exposed nose area of a vehicle. NOBODY gets in the vehicle expecting to be involved in a crash. But there they are.
Creative ideas for mounting location and plumbing are needed here, because fire/explosion safety is a major player. Of course the dedicated fan/cooler frees up solutions- but adds the component of live electric circuit on top of a relatively fragile cooler filled with gas.

 

[Frank]

I was surprised by the increased power with cooler gas though.
It would sure help mechanical pump systems, but the plumbing would be significant.

 

[InlineDave87]

I need to replace my thermo gun i had gotten a while back and see how hot the fuel rail is getting. Being the exhaust is right below the runners and fuel rail it may be worth it to do a fuel cooler and insulate the rail if youre running EFI. Plastic carb spacers I hear are good for insulating the carb from the intake manifold.

 

[Bronctopia]

If I recall right, drag racers used to use a fuel reservoir in an ice bath for this reason.
But their total travel time is in the seconds.
I think the easy way to cool EFI manifolds is just to increase bypass to the tank.
Carbs will always have the greater "problem" because fuel dead-ends in the bowl.
But then, what seems a problem in August may be a blessing in January. (Reverse months ifn OZ)

 

[InlineDave87]

If I recall right, drag racers used to use a fuel reservoir in an ice bath for this reason.
But their total travel time is in the seconds.
I think the easy way to cool EFI manifolds is just to increase bypass to the tank.
Carbs will always have the greater "problem" because fuel dead-ends in the bowl.
But then, what seems a problem in August may be a blessing in January. (Reverse months ifn OZ)

Yea, thats where the fan can be put on a switch. Im in South Texas so even January my truck can benefit from this. Our “Not Summers” might only get to the 50’s for like 3-4 weeks then were back up to triple digits. I may give it a try, but it may be some time before i get to experiment with it.

 

[Frank]

If I recall right, drag racers used to use a fuel reservoir in an ice bath for this reason.
But their total travel time is in the seconds.
I think the easy way to cool EFI manifolds is just to increase bypass to the tank.
Carbs will always have the greater "problem" because fuel dead-ends in the bowl.
But then, what seems a problem in August may be a blessing in January. (Reverse months ifn OZ)

Yeah the Engine Masters guys on the fuel temp episode found that the ice can was only moderately effective, less so than the trans cooler with the fan. They concluded the fuel was passing thru the coils too fast to cool sufficiently in that small can. As you said, a cool can is good for about one pass down the strip.
Also, a carb system can be set up with a return if one really wanted to, especially with a good electric pump. I've used low volume bleed returns on mechanical pump systems to eliminate pressure on the needle after hot shut down. Doubt it helped much with net temp, but some. It does reduce hot flooding and vapor lock.

Not sure how to increase flow on EFI without lowering pressure?

 

[aussie7mains]

Water injection! Cold air induction would be more effectively than trying to cool the fuel.

 

[Bronctopia]

Yeah the Engine Masters guys on the fuel temp episode found that the ice can was only moderately effective, less so than the trans cooler with the fan. They concluded the fuel was passing thru the coils too fast to cool sufficiently in that small can. As you said, a cool can is good for about one pass down the strip.
Also, a carb system can be set up with a return if one really wanted to, especially with a good electric pump. I've used low volume bleed returns on mechanical pump systems to eliminate pressure on the needle after hot shut down. Doubt it helped much with net temp, but some. It does reduce hot flooding and vapor lock.

Not sure how to increase flow on EFI without lowering pressure?

A more powerfull fuel pump will do it.
The fuel supply in traditional multi-port EFI comes from the pump to the fuel rail, passing by and feeding the injector bungs on the way to the fuel pressure regulator.
The regulator spills back to tank whatever volume of fuel is necessary to lower the pumps output pressure to what its spring is set to.
A more powerfull pump will require more volume spilled back to tank, thus increasing the flow through the fuel rail.
You are right that lowering the fuel pressure setting on the pressure regulator will result in the same increased fuel flow. But that seems to have vapor lock consequences on our non-crossflow Sixes.

 

[aussie7mains]

A more powerfull fuel pump will do it.
The fuel supply in traditional multi-port EFI comes from the pump to the fuel rail, passing by and feeding the injector bungs on the way to the fuel pressure regulator.
The regulator spills back to tank whatever volume of fuel is necessary to lower the pumps output pressure to what its spring is set to.
A more powerfull pump will require more volume spilled back to tank, thus increasing the flow through the fuel rail.
You are right that lowering the fuel pressure setting on the pressure regulator will result in the same increased fuel flow. But that seems to have vapor lock consequences on our non-crossflow Sixes.

You cant lower the fuel pressure without changing the ON time of injectors, they need a prescribed pressure to do their metering. This whole fuel cooler argument is IMO "playing around at the edges". Cool air coming into the intake will have far more benefit. As last resort water injection is a place to go, the change of state from liquid to vapor gives a useful temperature reduction. You could always consider n2O as a coolant!

 

[Frank]

A more powerfull fuel pump will do it.
The fuel supply in traditional multi-port EFI comes from the pump to the fuel rail, passing by and feeding the injector bungs on the way to the fuel pressure regulator.
The regulator spills back to tank whatever volume of fuel is necessary to lower the pumps output pressure to what its spring is set to.
A more powerfull pump will require more volume spilled back to tank, thus increasing the flow through the fuel rail.
You are right that lowering the fuel pressure setting on the pressure regulator will result in the same increased fuel flow. But that seems to have vapor lock consequences on our non-crossflow Sixes.

The in-tank pump on the EFI trucks is extremely strong. Even thru the tiny nylon outlet line it pumps a gallon per minute with a 10psi regulator. The factory fuel return line is too small to return increased pump pressure without raising the net pressure. EFI moves a lot of fuel, there's good cooling taking place as is. Adding the fan/cooler to the inlet side of a stock EFI would be more effective and much easier than replacing the pump and adding larger return lines.

 

[Frank]

Cool air coming into the intake will have far more benefit.

Indeed- to the tune of 1% density increase every 5*F of temp. drop. 120* under-hood air vs 60* piped ambient air = 12 more HP per 100 hp.

 

[CNC-Dude]

Moroso makes a cool can for that purpose, it's been around since the 70's. The fuel line is formed into a spiral inside an insulated can. You just fill it with ice......

 

[Bronctopia]

You cant lower the fuel pressure without changing the ON time of injectors, they need a prescribed pressure to do their metering. This whole fuel cooler argument is IMO "playing around at the edges". Cool air coming into the intake will have far more benefit. As last resort water injection is a place to go, the change of state from liquid to vapor gives a useful temperature reduction. You could always consider n2O as a coolant!

Completely agree about the "playing around at the edges". At least as far as power modification goes.
And yes, changing fuel pressure at injectors would require remapping, either way.
I assume if one is hunting such tiny fruit way up the tree things like cold air and programmable ECM would have been harvested way before.

 

[Bronctopia]

The in-tank pump on the EFI trucks is extremely strong. Even thru the tiny nylon outlet line it pumps a gallon per minute with a 10psi regulator. The factory fuel return line is too small to return increased pump pressure without raising the net pressure. EFI moves a lot of fuel, there's good cooling taking place as is. Adding the fan/cooler to the inlet side of a stock EFI would be more effective and much easier than replacing the pump and adding larger return lines.

Agree with everything you said, except the part about adding a fuel-air cooler being easier than upsizing a nylon return line and pump.

I decide to actually watch that video (with only minor ffwd-ing), and it looks like this phenomenon was only tested with a carb.

Carburetors are a finicky, trial/error evolved, multi-fluid, and multi-phase breed of analog devices. I wonder, and might be willing to bet on whether anyone has managed to ever numerically model their physics successfully.

Compared to fuel injection, what is going on internally is much MORE complicated, and I can completely see changing the fuel temperature affecting both vapor pressure, viscosity, and time to atomization and vaporization in unpredictable ways and locations within the witchery-sculpture that is a carburetor and manifold.

I think you and I both doubt the effects would be as noticable (if at all) in fuel injection.
And as long as you aren't vaporlocking the system, any fuel-density and post injection vaporization effects would be easier to manage in the fuel map.