water spray for I/C

[DeltaT]

I'll disagree with a couple points from above:

Now, if you don't mind, what is the temperature of the air coming out of the turbo at say, 15lbs boost?

-- Compressing air always generates heat. Going to 15psi with an 80% efficient compressor will increase the turbo output temp by about 210 degrees.

What is the temperature of that air coming out of a stock intercooler on an 80 degree day, with no heat soak on the intercooler?

-- Air-to-Air intercoolers also have an efficiency rating. I would estimate the stock Buick, with no heat soak (a real problem based on where it is located) to be 70% efficient in terms of heat shedding. So at 80 degrees, 15psi boost, your IC inlet temp will be about 290 degrees. At 70% efficiency, your IC will shed 147 degrees for a IC outlet temp of 143 degrees (80 ambient plus 63 (210-147)). You probably lose about 2-3psi through that IC as well.

Thoroughly chilling your IC, with CO2 or NOS, right before your run would yield a measurable increase in power, but only if you did it right before your launch, because it would heat up again quickly. Spraying supercooling gas on it during a run is an effective technique that has been used for some land speed records. If you only drag race you could go to a air-to-water IC with a big ice water reservoir that would be so effective that your IC-outlet temps would be lower than ambient, but it's not as good for a street car cuz the water heats up and is harder to cool back to ambient.

Jim

 

[4sfed4]

Originally posted by Razor
Thats why when it gets 40 degrees outside, you have to watch your tune, becuase if the air leaving the IC is 40 degrees, the alcohol will make its way into the motor but not have the same distribution. Best thing to do with alky when its cold outside is to bring the engine to full operating temps, Get the turbo nice and hot, intake nice and hot, etc.. before running it at high boost

Razor -

Just a thought.....

What about spraying the alky pre-IC to avoid any possible distribution issues in cool weather?

I do not think condensation of the alky in the IC will be a problem as that would require the average IC temperature to be below the dewpoint of the air leaving the turbo, which I do not think is possible?

 

[Razor]

Good question.. dunno till somebody tries it.

I'll see when winter comes... to Florida

 

[4sfed4]

In spraying alky pre-IC, one would lose a tad of intercooler capacity(since the temperature difference between the ambient air and the charge air would now be less as the alky will have reduced the charge air temperature entering the IC), but I am not sure if it would really matter in the overall scheme of things.

 

[DeltaT]

In addition to what 4sfed4 said, it is a lot more dangerous to have a nice, fat intercooler full of pressurized fuel/air mixture - no need to talk backfire - you're talking small bomb... also alky is very corrosive for the aluminum IC passages, which have lots of small fins, nooks and crannys - big time rot real quick, then pop.

Jim

 

[Razor]

Yes the chance of liquid collecting within the IC can be an issue if an excessive amount were to be sprayed. But more of a hydrolock scenario. Ive hit my intake piping with a lot of alcohol..I mean a lot.. and the motor feels like its drowning. But just driving around the condition clears up from the extra liquid collecting in the IC. Matter of less than a few minutes. I dont think corrossion would be an issue becuase alcohol, with the heat, pretty much vanishes rather quickly. Kinda like brake parts cleaner. And alcohol is only corrossive to items left sitting in it.

A concern would be time from the point of being sprayed, till the point it makes it into the motor. The further the nozzle is placed, the longer it takes. And it may not appear long.. but in the case of a car with a front mount, its a lot of tubing to travel, before it gets from point a to point b.

Maybe a neat thing to try would be a dual nozzle setup whereby one nozzle pre..one nozzle after. I know that on race cars running methanol, the intakes get iced down from running it.. so is it possible to get a greater temp reduction out of the IC... Dont know.. I would probably be more afraid to constantly be hitting the outside of the IC with -300 degrees freezing it and having the temp stress the metal, vs a once in a while misting internally that vanishes quickly. One thing for sure, none of the aluminum parts inside the motor from TB down have shown any signs of corrossion when using straight methanol. Hence why I suggested a pre IC nozzle. Notice suggest.. which means I havent tried it yet

If the temps drops outside heavily, tires get hard anyways.. not the time to be careless.

 

[kshef]

flash point of pure methanol is 11.112°C

 

[kshef]

facts about methanol
all alcohols are oxygenates(methanol, ethanol, propain, butanol)
the alcohol molecule has one or more oxygen, which contributes to the combustion

alcohols have higher flame speeds and extended flammability limits than gasolines.

alcohols burn with no luminous flame and produce less soot than ethanol,gasoline.

low volatility is indicated by high boiling point and high flash point.

the high latent heat of vaporization of alcohols cools the air entering the combustion chamber of the engine, thereby increasing the air density and mass flow. this leads to increased volumetric efficiency and reduced compression temperatures. together with the low level of combustion temperature, these effects also improve the thermal efficiency by 10%.
why would you not use methanol on forced induction engines...its beautiful

methanol has an octane of 106

 

[jsta6]

OK, I read up at various college and chemical sites on the Internet.

The "generally accepted" flash point of denatured alcohol is 57 degrees farenheit.

I don't think that trying to cool the intercooler down with CO2 or water spray will be counter productive to the flash point of the alcohol.

 

[Razor]

Amazingly what appeared to be a ricey post has turned into a rather informative read..

great going

 

[DeltaT]

Once you go through the numbers, I think you'll see that it's best to leave each task to the system designed to handle it - the IC is a charge cooler and the methanol is a mixture enrichment. You want the IC to strip out as much heat from the incoming stream as possible, then use the evaporative properties of methanol to further cool and enrich the airstream. As far as the corrosive effects of meth, my friend Bill didn't flush his fuel system for the last 3 races of the season, then didn't touch the car for 6 weeks. By then the alcohol had destroyed most of the anodized aluminum Earl's fittings on the car. The inside of most IC cores is raw aluminum. You need those little fins-on-fins to maximize your surface area and heat transfer from metal to air.

One last test of any hot idea is: Do I know any successful racers in any class that are doing this? I've never heard anyone spraying anythig into the inlet side of an intercooler, successful or not, though I agree it's not impossible.

Jim