Comments on: Engine Issues at Talladega: Vapor Lock, Gas Cans and Oil Coolers

By: bob emmons

bob emmons — Wed, 09 May 2012 17:42:22 +0000

Enjoy your explanations. Have referred your site to every racer I know. After a couple of years you will have enough to do another book.
PS: we’ve won the first two out of three.

By: Andy90

Andy90 — Tue, 08 May 2012 07:39:42 +0000

I wish that the TV “tech” commentators would spend their air time on things like this rather than telling me that a race tire is sticky and a shock absorber goes up and down.

By: Ella

Ella — Tue, 08 May 2012 00:44:35 +0000

I was puzzled during the race by the comment on TV about vapor lock. Thank yoiu for all of the information. I like knowing the “whys and where-fors”. I had been wondering if there was something basically wrong with either the new fuel or system.

By: diandra

diandra — Mon, 07 May 2012 21:02:22 +0000

Barry: Thanks for catching that. The key (as I’ve corrected it) is that the fundamental unit of energy in combustion is the number of molecules. Since that’s a hefty number (on the order of Avogadro’s number), you use more macroscopic variables. The next best thing to use would be mass because each molecule weighs the same regardless of whether it is part of a solid, liquid or gas. As soon as you go to volume, you’ve made an assumption about the density that may or may not be correct. Mass would be a more fundamental (and less confusing) quantity!

By: Barry

Barry — Mon, 07 May 2012 19:56:00 +0000

Diandra, you make a statement that I find confusing: “The second issue is that the density of fuel depends on temperature. Fuel becomes less dense at higher temperatures, so putting in the same weight would mean less volume. I’m checking to see whether teams take this into consideration.” You make it sound like the energy content of the fuel is a function of volume rather than mass. Can you clarify what you’re trying to say here?

By: diandra

diandra — Mon, 07 May 2012 18:19:54 +0000

Hi Dennis: Nope, I never get tired of being told I’m doing something useful!

I have a huge advantage over television in that I get to talk to the people who know after they’ve gotten to analyze their data. There’s no way of knowing these things in real time. The more subtle an effect is, the longer its going to take to understand it. Thanks!
DLP

By: Dennis

Dennis — Mon, 07 May 2012 18:14:32 +0000

I know you’re probably tired of comments like mine but I’m really appreciative of the analysis and giving us some specific numbers such as the temperature spread between the water and oil. It’s great to have someone on the “inside” with access to the engine builders. No idea why this info isn’t part of the TV broadcasts but even if it were, we’d still not get analysis like this. Great stuff Diandra!