Tuesday, March 10, 2009

Consumption - feeding the beast





First off I want to apologize for taking so long since my last blog update. My new job has been keeping me really busy but that's a good thing.

I wanted to talk a little about the amount of fuel and oil that the car consumes at a race. Above is a picture of the empty fuel and oil containers after unloading them from the trailer from the last race. As you can see we have to carry a lot of fuel and oil. We made 4 full runs with the car and did four warm ups in the pits. We used 35 gallons of nitromethane, 8 gallons of methanol and about 24 gallons of 70 weight oil. Keep in mind that we often warm the car up on methanol to cut down on our use of nitromethane which is much more expensive. We put 2.5 gallons of oil in the engine for a warm up and then drain it and put 3.5 gallons of fresh oil in for the run. Nitromethane dilutes oil in an engine very rapidly and turns 70 wt oil into yellow soup in a matter of seconds. That is why we have to change the oil so often.
For your consideration, the air to fuel ratio of a gasoline racing engine is about 12:1 meaning 12 parts air to 1 part gasoline. In a methanol/alcohol burning engine the ratio is about 6:1 so there is twice as much alcohol per part air as in a gasoline engine. Nitromethane is an oxygen carrying fuel so much less air is needed per part fuel. The ratio for nitromethane is around 3:1 - twice as much fuel per part air as an alcohol engine and 4 times as much as a gasoline engine. That gives you an explanation as to why the car needs so much fuel.

Another very quick fact for you gearheads is that the pistons in our engine at 9000 rpm go from 0 (TDC/BDC) to a top speed 307 mph (mid stroke) and back down to 0 again (TDC/BDC) twice per crankshaft revolution. Cool huh!

The other two pictures are of the car in its current state and loading it in the trailer to take it to get the chassis inspected and tagged for 2009. This is a safety precaution and is required to be done every year. As you can see in the pictures the short block is in the car. I should be receiving the heads in a couple of weeks. It will take me about 3 days to get the heads clearanced (valve guides and spring installed heights)and finish assembling the engine and clutch. I hope to be able to fire the engine a couple of weeks before our April 18th test session. Since we have changed some things and had everything completely apart over the winter it is a good idea to start the engine and check for leaks or any problems so they can be remedied before we load the car and head to the track.

As always thanks for viewing my blog!

Brad

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