Wednesday, July 4, 2007

A little car tech talk

Still the usual nothing going on today. We worked until lunch and then took the day off, I slept most of the afternoon. So some playing with the VW was again the highlight of the day.

A brief background. I am no longer running on the original motor for my car. I instead have the motor from a '91 GTI 8v. The GTI motor runs high compression, 10:1 compression, and that requires premium fuel. Back in Michigan most stations stocked 92 and Shell was even nice enough to carry 93. The higher the octane number the more resistant the fuel is to combustion, the higher compression the motor the more prone it is to combusting the fuel before the spark plug fires, a VERY bad thing. So the higher the octane fuel the better up to the point where detonation is no longer occuring. Down here in TX premium fuel is 91 octane. Another factor to detonation is air temp. Warmer fuel burns with less compression. In english what this means is the warmer Texas air combined with the lower octane Texas fuel has ment my motor is running at less than optimal power output.

I went out in search of a good octane booster today, actually I was at Wal*Mart already and decided to check out their selection. Found some stuff by STP that boasted "the highest amount of MMT" and "barely street legal". None of that really means anything to me so I grabbed the product from Prestone. Their label says each bottle when added to a full tank of gas will increase you octane number one point. So starting at 91 octane one bottle would take me to 92 octane and so on. The icing on the cake letting me know this was a good choice was that it required photo ID to purchase. Of course I did not have a full tank of gas and had no intention of paying just to get to where premium gas is in Michigan. I had just less than a half of a tank of fuel and bought two bottles. I don't know how high a grade octane my motor will benifit from but I have run 94 through it before and felt an improvement over 92 so I was eager to try this out. By the time I pulled out of the parking lot I could feel a difference. I'm not sure how much faster it makes the car but the need to downshift to accelerate on the highway was diminished and that's good real world results.

Odds are good if you keep reading this blog you're likely to learn alot more about the internal combustion engine, it's just kinda what I do.


MOM JONES! said...

Whew! That car tech talk went right by me! Sorry ... I'm glad you know what it means, Jes! It sounds like you are on top of the situation!

Missing all of you this 4th of July!