How to make your engine faster. Part 2

It’s time for part 2 of “How to make your engine faster”. Let’s take a look at tires. This is another one of those subjects that we tend to keep close to the vest. We try to make the tires stick as much as possible to lessen the tendency of the kart to slide off the track. This is good, if your driver is learning. We are moving ahead and our driver is now in contention to win a race. The tendency is still there to keep the kart from sliding of the track. Therefore, the air pressure is lowered and the kart goes slower. There is a very fine window of approx. 1 psi high or low. How do I know if the tires have the correct air pressure within 1 psi?

#1 The driver will tell you. #2 The tires will tell you. #3 The lap times will tell you.

The driver is the most varied barometer of how the tires are working. Because he/she is dealing with the feeling at the seat and steering wheel. You, the crew chiefs are trying to focus on just the tires at this time. So, we look at the tires. The surface of the tires should look very close to the same at all four corners. The texture of the tires should have a slight grain to it similar to medium sandpaper. Last, the lap times will indicate if you’re too loose or hooked up.

The closer to the optimum air pressure, to give you that ultimate speed vs. grip. The more your driver is going to have to be careful, not to over drive the kart. That is one example why our air pressure may be different from yours. The other reasons are the chassis setup and driving styles.

Now your kart is in the lead, the engine begins to loose power in the later laps of the race and begins to give up places. It may not be your engine! Air expands as the tires heat up and that means the psi goes up. I have a fix for that. Nitrogen! Nitrogen has larger molecules than CO2. Nitrogen will not expand nearly as much when the temp goes up. And nitrogen doesn’t leak out as quickly as CO2.

You can, use the expanding air pressure to your advantage. By having the tires stick in the early stages of the race, then build up psi in the later. This is where you have to make a decision. Nitrogen or CO2. More psi or less. Keep good notes.



I know that I am not covering these subjects so completely that no one has anything to add. Come on. Tell me what you think. One driver came up to me at last weekends Dixon race and told me that he enjoyed reading Part 1. Thanks for that. I'm not going to take all the credit for his first win. lol

Good stuff, Neil, keep it coming! I would also add a infrared temp gun can be handy for checking tire temps right after the kart comes off the track, but like Neil, I alwys look for the grain pattern on the tires.