BrandonS

I plan on installing a custom made fuel cooler. Basically, and cylindrical container through which the fuel lines are rooted, and then after which they enter the engine. Inside the cylinder the lines are coiled over, and the cylinder filled with packed ice. This setup seems pretty feasable, but what would the effects be on the car?? Thnx

Brandon

The Unabageler

my _guesses_:
the fuel will burn slower, _could_ cause detonation.
fuel density will be higher so it _could_ make your mixture too rich.

dhayner

There won't be any effect at all. The O2 sensor calls for the proper amount of fuel to combine with the amount of air being inducted. The air/fuel ratio is a weight ratio, and will be the same with either temperature fuel. The proper amount of cold fuel will have a slightly smaller volume than that of warmer fuel, but will have the same weight.

BrandonS

I disagree about the first post, but hey, what do i know! As far as the 02 sensor, is there a way to bypass it?? I've heard of resetting the computer to help with a CAI, but will it work for my problem? Also, what effect would resetting the computer have on my Vtech controller.... that i havn't installed yet?? thnx

Brandon

The Unabageler

you sure it's weight based? that would be a LOT more math than is necessary to calculate mixture ratios...esp. since most liquids and gasses are measured by volume in the real world and the lab. the air pressure and temperature is measured by the IAT and MAP sensors, which can easily give volume by basic gas law. fuel pressure is regulated, and the injectors think in terms of pulse time. flow pressure over time is easily translated to volume if the density/temp is assumed constant. do we have a fuel temp gauge? not last time i checked, but i could be wrong...

Sunder

While you're at it, you may as well throw in a umbrella and a slice of lemon for all the good it's going to do

While AFR ratios are actually represented by weight, not by volume, the amount of fuel that gets pumped in, is controlled by what comes out of your exhaust. So neither weight nor volume will affect how rich or lean your engine runs. (It may in the short term, but a few runs in closed loop, and the computer will adapt)

As for the idea of having a cold charge, that's suspect too. I mean seriously, you expect 14:1 parts of fuel which might be a couple degrees colder than the air, to make a difference in air density? By that time, it's too late anyway - the air is in, the valves are closed, you have your mass of air about to be ignited.

jzr

One evening my car showed a +5 or +6 hp gain after dumping in an icy cold 5 gallons that had been sitting outside. At the time my only mods were an exhaust and air filter.

Most of the gain was gone by the second pull, and by the third the output was back to normal.

Generally, the cooler the mixture entering the chamber the better. Unfortunately my guess is that any sort of fuel cooler of reasonable dimension would not be able to refrigerate things enough to do you much, if any, good.

YMMV

dhayner

In the sense that fuel has a certain number of carbon and hydrogen atoms per pound, it's weight-based.

The O2 sensor and ECU don't care if the atoms came from more or less dense (colder or warmer) fuel, they just call for the right number of atoms to combine correctly with the oxygen in the air.

marcucci

Am I the only person that remembers this as an old drag racer's trick?

AFAIK the only gain is what comes from cooling the intake charge from. I would think that cooler fuel would be more likely to condense and less likely to atomize, but I honestly am not sure.

I do agree that it would have limited benefits on this motor. If you are going to go through that much trouble, I'd do the Hondata manifold insulator and the coolant bypass; would probably give you much greater gains.

ultimate lurker

Bingo.

Fluids are generally incompressible. That means their density doesn't go up or down as temps change. However, one of the operating requirements of a gasoline engine is that you properly vaporize the fuel charge to ensure complete mixing and burning. The fuel injector does a decent job of doing this, but the fuel is also vaporized by hitting the hot parts in the intake tract and combustion chamber (intake valve being a big one). Vaporization requires heat. The colder the fluid starts, the more heat it takes to vaporize. That heat has to come from somewhere and it comes from the intake charge, cylinder head, etc. Cooling that stuff off is generally beneficial for power.

That said, like Marcucci, I think its not worth it for anything but a dedicated drag car.

UL

[QUOTE]Originally posted by marcucci
[B]
AFAIK the only gain is what comes from cooling the intake charge from. I would think that cooler fuel would be more likely to condense and less likely to atomize, but I honestly am not sure.