Just got done putting this together , how well they work ..I guess I'll find out . All I have to do now isre-install the tank and start her up !

 

is this really necessary?

 

To answer your question ......... no its not , but owning an RX7 isn't a necessity either , but we still do it dont we ?
Do you know hot a rotary cars' engine bay gets ? have you ever felt the temperature of the gas tank after driving ? If the turbo gets an inter cooler , why cant the pumps ? the very same principles apply here too.Cool fuel also benefits the pumps , extending their life.

 

let us know with results

 

I have always wanted to put a small transmission oil cooler to cool the fuel. Not sure if it would work or not.

 

Once I had one of those ....., my motor was tuned to 15psi @6300 rpm's where I made 350whp. I decided to put in one of those coolers, it immediately went full rich when I added it ! go figure .

 

this still doesn't prevent the fuel from getting obscenely hot as soon as it passes under the UIM

 

yes, but dropping the temp a few more degrees will help it see a cooler injection temp. Remember people, its simple science. Cooler fuel is denser fuel, thusly making the potential for more power and I have seen a few cars gain mileage from this. Albeit, not a lot of mileage, but something is better than nothing :P

 

Fuel CAN NOT get obscenely hot AS SOON as it passes under the UIM !!!!! the fuel rails are not designed as heat exchangers , they do not have an extended inner surface area to promote heat excange and the fuel passes through the system too quickly for this to happen. However , when it all gets hot "heat soak " sets in and as the system is run for a while it gradyally absorbs heat from the hot fuel rails .Some of the energy delivered by the fuel pump is also lost as waste heat to the fuel . in fact the fuels' job is to also cool the pump !!! Removing this heat can only be a benefit.

 

Your on the right track.....but it doesn't really work as well as you think. The amount of "cooling" that the fuel cooler will provide is not enough to drasticly change the molecular structure so as to see benifits from it being denser.
Is it "bad" to run one? No. But I don't think you need one unless your going to be engineering it on a greater scale.

-J

 

Are any of these replys based on fact ? do any of you have fuel temp. gauges installed ? have you ever done a "with and without it " comparison ?

 

Do those coolers you chose act like heatsinks? Doesn't seem like there would be much beneficial airflow in their position.

 

DEI sells a fuel bar that you flood with CO2 that cools the fuel. The bar actually gets icy when activated. Don't know if or how well it works. I have the full DEI system (fuel, air and IC sprayer) but car is not yet up and running.

 

We are using this exact cooler in the rear of our car as a fuel cooler. The way its designed however, with the fins running the length of it, it should be mounted in parallel with the airflow under the car for optimum cooling.
How much it cools the fuel is unknown as we have no way to monitor it, but yea, as others have said, it sure can't hurt!

 

interesting idea... i am running 2 fuel pumps in tank (cars not running yet) and i was worried about slowly heating up the entire tank of fuel since im running two pumps. also since im running two pumps i will have a ton of fuel recirculating through the system (any time besides full boost) which should be significant as its a street car. That's alot of fuel constantly circulating, so (im assuming more heat picked up from the engine compartment being dumped back into the tank) as well as 2 pumps running in the tank. and yeah, in tank pumps are cooled by fuel (and having one pump fail in a 2 pump system is dangerous) so i think im going to look into one of these.

where did you get them and how much were they? are they -6an or -8? and do you have it on the return line or feed line? since i have a two pump system with independent lines i think my only option would be on the return line. nice work!
-Heath

 

all i see is clutter, a hole in your pocket, and mere speculation about performance benefits. As soon as the fuel gets into the intake ports it gets hot as ****. Whether its initial temperature was 100 degrees fahrenheit before you added the fuel cooler and 80 degrees after you added the fuel cooler, it's still going to get hot as ****. It's still going to preignite if there's enough heat in the combustion chamber and the octane of the fuel isn't high enough.

and what's this about cooler fuel being more dense so there's more power? where does that come from? And cooling the fuel pump? Yes fuel cools the pump, but if running your fuel pump too hot is even a concern you're just pushing it too hard and you need a better pump.

People really overbuild their fuel systems here. J-rat made 550 to the wheels with a single whinebro, 890/1680, C16 and meth injection. With race gas I ran 21psi on a T04s (granted, not huge power numbers there) with fuel rails still in series and a rewired Supra TT pump.

 

Thanks Heath , I bought them both on ebay one was $15 and theother $30 , the smaller one is the supply flow , it also has afilter in it .The larger is on the fuel return line ,its actually a transmission cooler .The supply is #10 and the return is #8, I drilled and tapped them both to accept those sizes.

Well sir thats what YOU see , doesn't mean thats what it is ! $45 dollars is hardly any kind of money to bitch about , U own an RX7 for Christ sake ! Speculation ? maybe thats why REAL drag racers have always tried to cool their fuel (the cool can) and barry Grant and perma cool have both produced fuel coolers ! I personally experienced a difference with the addition of a fuel cooler , have you ?

If this were true , it would self ignite and blow the F@%&K out of the motor and the LIM !!! the intake port is the coolest part of the motor.

Where did you get your numbers from ? out you A$$ , I'm sure.

Very true !! did you know that hot fuel can cause detonation ? this is exactly why people (like myself and others) try to cool it ! Why do you think a tuner richens up the mixture under boost ? this is for the excess fuel to absorb the excess heat and stave off detonation , dont you think this would be more effective if the coolant (fuel here) was cool?

Everyone and there grand mother knows the hotter a fluid is (liquid or vapour) the more excited its molecules are and the less dense it becomes ! U have a problem understanding BASIC physics? If the fuel is cooler it will be more dense , allowing more ignition and more boost and yes more power !!!! The duty cycle of the fuel injectors is also reduced , since more fuel is injected at the same pulse width.

And how exactly do you suggest I not push my pumps too hard ? should I some how slow them down ? or wait yes , this would require me to buy a pump speed controller for $260+ , but $45 is soo much , that it makes holes in pockets . Part of the reason why I think I need cooling is because the pumps are SOOO damn good (Bosch '044X2) !!!!! they generate high pressures and flows and as we all know (well I assume that we all do) ,the by-product generated is HEAT.
Mazda attempted to fix this problem by employing a resistor in the circuit to slow the pump down during low load conditions.


What exactly is your point here ?? I would prefer to over engineer my systems rather than do the opposite ! its like having a condom ......better you have one and not need it than you need one and not have it !!!!!!!

 

I think that the temperature difference a fuel cooler will provide will have little effect on the density of the actual fuel, as a 20 degree F drop in water will only increase its specific gravity by like 0.003... (temperature doesn't affect the density of a non-compressible fluid nearly as much as a compressible one) but this could have a more pronounced effect on the air intake charge. I don't think that an air-cooled fuel cooler will have much of an effect on power, but I do think it would definitely help keep the temperature of circulated fuel down over an extended period of time. The fuel will not gain a huge amount of heat as it passes through the rails once, but after continuously being passed through the pump and rails it WILL start to heat up. There is quite a bit of friction in all that plumbing in addition to the entropy gain from the engine...

That being said, I'm running a 3' air-cooled fuel cooler to replace some of the line that would run from the cell to the engine. Not sure if it will make a difference or not, but I only paid $5 for it from the scrapyard...

 

Is it me or is there some hostility between these to?

 

No hostility here !! I am just always up for a good debate !

 

ive researched this in the past,
it doesnt really help out performance, but when cooling the return fuel it will lower the temp of gas in the gas tank, resulting in less vaporization and like said before it will help the fuel pumps run a few degrees cooler.
As for performance, cold fuel doesnt atomize with air as well as hot fuel, though you will have a better chance of detination, so you really need to pick the battle you would rather win.

 

yeah thats the conclusion i came to... youre not gonna get any performance gain, but it should cool the return fuel so your tank of fuel doesnt get too hot (especially with 2 pumps)... and since it doesnt add any significant restriction in the return line theres no reason not to try it. for one pump i wouldnt bother.

 

Although I'm not utilizing a fuel temp sensor, I observed on the dyno (I'll be back saturday and will check again) fuel rail temperatures around 60C after several pulls and about 40 minutes run time. This was using an infared/specrothermometer deal (hand held lazer one)

IMO at low power and boost (sub 25psi, sub 500whp) you're not going to "require" a fuel cooler................but its certainly not going to hurt anything, and most of those types of setups (like single finned rail replacing some line under the car) are SUPER cheap and easy to do so why not?

 

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