My 2006 Sport has more power in the cold.

wheel spin all the time when

Cold air is more dense so you get more air into the cylinders and with the right amount of fuel more power. Haven't checked our 2007 but would have thought that in cold weather input air would be taken from that warmed by a manifold.

wheel spin all the time when

Could it be the tires?

snipped-for-privacy@spymac.com wrote in news: snipped-for-privacy@n59g2000hsh.googlegroups.com:

I just bought this car (new) a little over a month ago, so I don't think it's the tires, plus the pavement isn't slippery.

the tires, plus the pavement isn't

Not sure how cold you're referring to but if you're on summer tires and the temperature is getting within a few degrees of freezing then you will have reduced traction.

Also since you're new with the car it could be that you're starting to push it a little harder having gotten more friendly with it :-)

Kind regards Bruno

PS. For the older MX-5 models one can buy cold air intake systems giving the engine extra power by taking air in directly from the front and not just from inside the engine bay. It's a cheap and reliable power upgrade.

Having dealt with a number of Jackson Racing Cold Air intakes, I would never install that unit again on any miata. I still have never seen one that did not start cracking within a few years, and those cracks can start on the bottom where they can not be seen. One that I took apart had obviously been letting air and particles in past the filter for who knows how long.

If I ever go with another normally aspirated miata, I will get the Randall Cowl system that routes the air from the windshield area. It requires cutting a hole in the firewall but it is still a better option, imo.

Of course, if anyone wants the JR CAI from the 1.6 liter that I have torn down, I think that they are fantastic products, cracked air intake box and all. ;-)

Pat

it's the tires, plus the pavement isn't

Yep, that's what I was wondering about. If it's summer tires I would guess they'd break loose sooner in 40 degree weather than 70.

Yes, you do. The incoming air is denser when it's cold, so you can get more air/fuel mix into the cylinders. It's a small effect, though.

That's more likely because the tires don't grip when they're cold.

I've noticed I get wheel spin all the time (even in 5th gear) when driving on snow and ice. That doesn't mean my 2003 has more power when driving on snow/ice.

Of course it's the tires.

The age of the car is irrelevent. At colder temperatures, the tire is going to have less grip. That's the way "rubber" works. That's why race drivers weave back and forth during pace laps: they're trying to keep the tires hot so they grip well.

The tires are.

Absolutely, I have never seen a drag racer above street level who didn't heat up their tires as well before the race for exactly the same reason.

I just drove home in freakishly cold weather for central Texas. My summer tires were slipping a lot easier than they did yesterday.

Pat

We all will pretty much agree that with enough temperature differential, traction can be measurably altered but, I know in both my Miata's (NA and NB) they definitely have more power in the cold weather (the denser air mentioned earlier) so unless the NC somehow negates this, it's probably a combination of the two that he's feeling, eh?

By the by; It's been below 40f most all day here in the Houston area after a couple of the nicest 80+f days of the year!

Chris

Yes.

Unless his engine is knocking badly and being retarded by the engine computer when hot, the difference isn't big. The change in air density from 90F to 40F is a little less than 10%.

I'm betting that the change in grip for typical summer tires for the same temperature drop is far more than 10%. At least it sure feels like a lot more than 10% less grip for most of the non snow-tires I've driven on.

Here in Minneapolis it was in the 70s not long ago. The low last night was 15.

Maybe it's because snow is white!

Doh! I should have thought of that.