Cool Fuel ?

[1 in 2000]

Ever noticed these cars run much nicer, more horsepower, and less lag on a cool dry morning. After the car has sat on hot pavement at work all day and as soon as I start it it's not the same high energy car I drove into work with. It even makes a gurgling sound during any acceleration, soft or hard, but usually only in the afternoon.
Now I know air density and moisture may play a part, but what about temperature of the fuel tank?

 

[novaderrik]

you can get something called a "cool can" for low pressure fuel systems. it it just an insulated bucket with the fuel line coiled thru it that you fill with ice water. drag racers used to run them a lot.
i'veh eard of people sith carbureted cars running their fuel line thru an old AC condensor to cool the fuel down.
i'm sure you could do something similar on a high pressure efi setup- maybe with a tranny cooler type of radiator in front of the engine radiator.

 

[Jerryl]

Ever noticed these cars run much nicer, more horsepower, and less lag on a cool dry morning. After the car has sat on hot pavement at work all day and as soon as I start it it's not the same high energy car I drove into work with. It even makes a gurgling sound during any acceleration, soft or hard, but usually only in the afternoon.
Now I know air density and moisture may play a part, but what about temperature of the fuel tank?

Cooling the fuel does work, but ………. A good pump with the right voltage and filters puts out around 280lph.
At idle, +95% is returned to the tank.
So the “heat soaked fuel under the hood” (which is a small % of the total available volume with a full tank of gas) is returned to the tank very quickly.

The fuel in the tank is at around ambient temp.
Lowering temp of the fuel from ambient at WOT, takes quite a bit, because of the volume going through. Even with an “ice can” I bet you can only lower the temp about 10F (I pulled that number from you know where ) .

Your observation of a HA motor being very heat sensitive is very true, but I am not sure if “cooling the fuel” will result in noticeable performance increase. The IC’d cars have very similar fuel temp issues, but they seem to run stronger overall on hot heat soaked days.

If you ever have a chance, log the MAT on a HA vs. an IC’d car.
You will be amazed.

Your observation of comparison is “cool dry days”.
There is no solution for that other than “cool dry days”.

The "gurgling sound" may be a function of the fuel map, i.e. running rich.
What chip/set-up are you running? What does the WB say when it "gurgles"?

 

[charlief1]

If you hear the "gurgling" noise from inside the cabin and the windows are up you may be hearing the heater core. This is a common problem on the G bodies as well as some of the earlier RWD vehicles.

 

[1 in 2000]

The "gurgling sound" may be a function of the fuel map, i.e. running rich.
What chip/set-up are you running? What does the WB say when it "gurgles"?

Im not sure of the chip. I bought it about 15 + years ago at a Kirban event, I'll have to pop open the ECM and take a look at the lable. No WB, no scan tool just been using my 5 senses for 20 years / 100k + miles. Just bought a FP, HW kit, boost and knock guage. I may do some tuning, but for now the car runs clean and strong with the exception of hard warm startup, slight studder @ WOT and an annoying gurgling in the afternoon. Im hoping the new fuel pump will clear most or all of it up.

 

[Jerryl]

Im not sure of the chip. I bought it about 15 + years ago at a Kirban event, I'll have to pop open the ECM and take a look at the lable. No WB, no scan tool just been using my 5 senses for 20 years / 100k + miles. Just bought a FP, HW kit, boost and knock guage. I may do some tuning, but for now the car runs clean and strong with the exception of hard warm startup, slight studder @ WOT and an annoying gurgling in the afternoon. Im hoping the new fuel pump will clear most or all of it up.

Sounds like your senses are working better than mine.
Maybe the pump will take care of it.
If that doesn't, a scantool would be nice to review operating paremeters, and more specifically, the MAF.
Post back and let us know what you find. :smile:

 

[1 in 2000]

If you hear the "gurgling" noise from inside the cabin and the windows are up you may be hearing the heater core. This is a common problem on the G bodies as well as some of the earlier RWD vehicles.

Nah, It's coming from the engine compartment. It almost sounds like Im running bad gas and I hear it best when driving thru enclosed area's (next to concrete retaining walls, etc.) and it's only on warm afternoons. It is strange, but it could just be something simple like the type of oil the guys at the garage are putting in it?

 

[1 in 2000]

Sounds like your senses are working better than mine.
Maybe the pump will take care of it.
If that doesn't, a scantool would be nice to review operating paremeters, and more specifically, the MAF.
Post back and let us know what you find. :smile:

Thanks, What type of scantool would you suggest for an 84 ECM? I'd like to get one so I can check on things now and then and I have a laptop all ready to use. Problem is Im not sure I'd be getting a big enough bang for the buck with the older ECM.

 

[1 in 2000]

Back to the subject....Anyone seen one of these

Heat Sink

 

[Jerryl]

Thanks, What type of scantool would you suggest for an 84 ECM? I'd like to get one so I can check on things now and then and I have a laptop all ready to use. Problem is Im not sure I'd be getting a big enough bang for the buck with the older ECM.

Try this.
http://www.turbobuick.com/forums/parts-sale/193999-winaldl-turbometer-pro-cables-free-scantools.html
You can also look for an OTC scanner.
The PC system is preferred since it allows you to log.

Heat Sink

The problem in my mind with a heat sink is this;
If the temp of the fluid is hotter than ambient temp, it will cool the fuel.
If the ambient temp is hotter than the fluid, it will heat up the fuel.

While I will not argue with the "gurgling sound" and "lack of performance when hot", I highly doubt it is fuel temp related.

Edit;
Did the gurgling sound just start, or has that always been the case?

 

[asloan5]

I can attest for the large pumps heating up fuel I have a cell and fuelab pump which moves enough fuel to support 1200 hp. on a 1 hour trip on the highway in florida 90 degree temp my cell was so hot I could barely touch it. my pump has 2 speed capability and the way they are shipped from factory is on high speed all the time. I set it to stay on low speed until 5psi of boost and what a world of difference in the temp of my fuel cell.

 

[1 in 2000]

Try this.
http://www.turbobuick.com/forums/parts-sale/193999-winaldl-turbometer-pro-cables-free-scantools.html

Edit;
Did the gurgling sound just start, or has that always been the case?

It's been doing it as long as I can remember, either it's getting louder or I'm getting older, because it's been bothering me more lately.

Yeah, I'd definitely put any kind of cooling on the return line keeping the pump and tank cool also.

Thanks for the scantool info.

 

[1 in 2000]

I can attest for the large pumps heating up fuel I have a cell and fuelab pump which moves enough fuel to support 1200 hp. on a 1 hour trip on the highway in florida 90 degree temp my cell was so hot I could barely touch it. my pump has 2 speed capability and the way they are shipped from factory is on high speed all the time. I set it to stay on low speed until 5psi of boost and what a world of difference in the temp of my fuel cell.

Luckly you didn't lose the pump.