I'm running Michelin Pilot Sport PS2s in 245/40/18 on stock wheels.

The issue I have is, I have the tires filled with Nitrogen, so the pressue stays the same hot or cold.
So, I am trying to figure out what a good hot inflation pressue (with air) or overall Nitrogen inflation pressure would be, as the cold measures don't do me much good.
I used to run about 32 cold in the stock Bridgestone...er.. tires (they barely qualify as that) 36 cold in my BFG KDW2s, and 28 cold in my Pilot Sport Cups.
They all used to end up running about 36-40lbs hot.

Currently I'm running 36lbs all the way around. I hadn't really thought about it much, but, I have a track event this weekend so I'd like to hear if anybody else with PS2s has some "hot" inflation pressures that workd for them on this car.

Thanks.

 

Mazda's factory recommended air pressure is 32 psi in the front and rear. Regrettably there isn't one pressure that is going to be perfect for all track conditions. The best air pressure for the track event can vary depending on track temperature, How many and what type of turns, tire condition. I would recommend starting around 35 psi for the track and adjusting the air pressure to suit the conditions.

On a side note about filling a tire with nitrogen. I would not recommend using nitrogen in tires when you have them installed. The problem is that when you add normal air to the nitrogen you eliminate all the attributes of the nitrogen. Most professional racing groups use nitrogen Because it is so resistant to temperature change. However true professional competition wheels have two valve stems specifically used for nitrogen. one valve stem is for sucking out the plain air and moisture. The other valve stem is for pumping in the nitrogen to ensure that it stays as pure as possible. when the tires are re inflated or adjusted it is done with pure nitrogen.

 

Thanks for the tips Connor. Pretty much what I expected. I'm used to playing with the pressures alot, but hadn't had to worry about mixing the air and nitrogen before.

Honestly, I mostly got the tires done with Nitrogen because the tire-shop just started to offer it, and offered to do mine when I was getting the tires installed. Thought I'd try it for interests sake.
They did offer to have me come back and they'd adjust the pressures as I liked, but, by the time I figure it out with trial and error, well, I'll be done with this.

Also, at the time, I didn't think my 8 would be going on-track any more, so I wasn't as worried about optimum hot pressures. But, I need to take it out one more time, so here I am.

 

You need to shoot for around 42psi when at operating temp. (HOT) Perhaps 1-2psi lower in the rear. I start around 36psi with regular air and I end up around 42psi after lapping.

 

isnt the oem tire size 225/45/18?

 

How do you like the PS2's so far?

just looking for input because i might get some.

thanks

 

we run them at roughly 40F/42R (Hot) at the track. Around town the setting is 32F and 37rear. The do pretty well at the track for a street tire.