I've thought about this from time to time, and now am doing it again when I see the 94F temps for the upcoming 1/2 Mile event this weekend. I can usually do a run or two at that temp before my fuel pump (Bosh 420) is just screaming for mercy. I start to get a little nervous at that point and let it cool down for a while.

I know that jbsblown has fuel coolers on his incoming/return lines, but I'm curious if anyone else has done it as well? If so, which coolers did you use? Where did you place them? Etc.. I'd like to learn a bit more about the setup.

 

Place them wherever you can get some airflow to allow them to cool a little. Although I'd maybe refrain from locating them at vehicle extremities just so they wouldnt be in a direct path of damage should there be a minor crash
Fuel coolers are very common on diesel vehicles these days, where they simply install them underneath the car so not even where there is great airflow through the actual cooler itself. But really fuel temps shouldnt be getting that high in the first place.

And any cooler design with a decent amount of fluid flow will work fine on the low pressure return.

Whether it's a conventional oil cooler type, or the long bendy tube/fin type...really depends what is easiest for you.

And are you saying fuel temp is 94degF or ambient ? Certainly 94degF for fuel temp would be of no concern

What sort of fuel temps are you seeing ?

What is a Bosch 420 ?

 

I'm not sure what the fuel temps are, but the 94F is ambient temperature. The fuel pump is a Bosch pump that is 420 lb per hour.

Just looking to see if anyone else has run fuel coolers on their cars and if they have had any issues with the fuel getting hot. I just know after a couple of runs my fuel pump just starts buzzing pretty dang loud until I let the car cool down a little. I don't know if I should be concerned about that, which is the point of the post.

 

there really is no need for a fuel cooler any more. You don't need to worry about vapor lock.

 

realistically the best way to keep your fuel cool is to not have waaaay more pump than you need.

 

I was thinking more along the lines of what it does to the octane rating.

 

the science shows that as temperature increases, effective octane rating increases....

 

JBSblown installed a cooler because his car was shutting down all the time. He thought it was vapor locking on him due to over pumping the fuel (which I've seen with certain aftermarket pumps), but it turned out to be caused by a burned up leg on the relay pin inside his fuse block. I know this because I spent hours on the phone with him isolating the trouble.

 

Bosch do not make any pump larger than the 044...which Bosch quote as 180lph, although in reality they flow around 320-330lph depending on pressure/installation.

So not sure what this "420" is

I've had a cooler fitted to mine for around 10 years. Not really because of any problem...just simply I had an oil cooler sitting on the shelf I'd got for something else...and decided why not. Although I do live in a relatively cold environment so nothing like Florida temps. For most part I ran a pair of Bosch 044's although later did switch to AEM 380's for a year

My cooler is simply installed under the vehicle, with no real airflow directed to it as such ( non vette ). I also have a fairly large tank at around 75 litre capacity and would rarely ever run it less than 25 litres.

But pretty much never in all the time I've used the car have I had any problems I could attribute to hot fuel. The only time fuel temps have even got hot, are sitting in traffic on warm days for extended periods. Or if the car had been sitting parked the sensor would get heat soaked, but immediately fuel starts moving again it would cool down. Sensor is mounted on a small distribution manifold before the rails, in the engine compartment
However, last year with the AEM pumps, I did get stuck in some really shitty traffic on a very hot sunny day for here in the UK, with temps probably close to 90degF and when fuel temps got in the 110-120degF range the AEM pumps did start to scream a bit. Fuel pressure etc was still all fine, maybe just dropped a fraction but the pumps were noisy. I think fuel level around that time might have been down to 30-40litres in the tank
But even a cooler in those circumstances will do nothing unless it is mounted with some airflow, in fact depending where it is installed...it might even make things worse and could well be the case for mine. When moving through that would change.

But fuel pumps like that screaming can also be if they are strangled from a good gravity fed clean supply of fuel. Never run small lines, long lines or have them try and suck. No EFI pumps will be happy if they do not have good access to fuel.

But with the exception of the above in the many years I've logged fuel temp, when the vehicle is running and being driven I've almost never seen fuel temps above 90degF or so. More often it is around ambient

And most of the heat does come from circulating fuel into the hot engine compartment/rails and back to the tank. If you're a smaller tank, clearly this fuel will heat up faster than if you had a larger amount of fuel in the tank.
A small amount comes from the pumps work itself.

 

"the science shows that as temperature increases, effective octane rating increases...."
Do you mean fuel or air temp?
I would think the phase change cooling of vaporization would come into play- so would not the cooler fuel absorb more heat? Or is it chemically linked to octane?
I have run a cooling can on ther vehicles with good results.Of course I was also dealing with fairly high ambient temps.
The fuels density would also change with temperture and effect mixture

 

I'm just simply quoting exactly what's on my build sheet provided by Speed Inc. We're talking about the same thing from what I've gathered.

Here is some info from LS1Tech:

"The 420 name you US guys use comes from 420 lb/hr

Bosch rate it at 180 litres per hour....most others around the world suggest closer to 330 litres per hour.

Either way, it is a very capable and reliable pump. Ive never tested a single, but I tested my dual 044 setup, and they flowed approx 486 litres per hour at 13.1v, 60psi test pressure pumping through through a single -6 line."

Thanks for everything you've posted and everyone else's comments as well. The pump making excessive noise does worry me, but it's more the lack of understanding what's going on that compounds the issue. Doesn't sound like I should worry about it too much. It's been on there several years without problems, but I've always wondered if it could be done "a better way". Thanks guys!!

 

The 420 makes sense now...lb/hr as opposed to lph.

And pretty sure what you quoted above...was me ! lol A few years ago.

As for heat, octane, whatever....I'd doubt it. But either way I cannot see any circumstances where overly hot fuel is of any benefit, or is desired.

But all too often people say they have problems with hot fuel...but every time I asked how hot, they have never measured it.

But I will also always say if there is any concern at all, just fit a cooler. It's simple and can do no harm.

 

the temperature of the fuel. Lemme see if I can figure out how to attach the published SAE paper on it.