Car feels slower in this 100 degree Texas heat

[AustinTrkJunkie]

Yes, it's hot here in Texas, but I still feel like I can discern a more significant loss in power than just the 102 temps here in Austin are exacting from the turbos. Case in point, a stock - well seemingly anyway - Subaru Legacy gave me a run for my money today on the tollway. Usually would have been lengths ahead, but today, not so much.

Yes, this is whiny, so spare me "buy another car if you hate it so much". Love the M3, the car just feels down on power overall, outside of 100+ temps...

thoughts?

[neilum]

Wouldn't the suby also be affected by the heat (even moreso)?

And you had to simply be traction limited and spinning your wheels otherwise there is no way in hell it would be close caused solely by the heat

[AustinTrkJunkie]

Originally Posted by neilum

Wouldn't the suby also be affected by the heat (even moreso)?

And you had to simply be traction limited and spinning your wheels otherwise there is no way in hell it would be close caused solely by the heat

This was a roll pushing 80ish to start...so wheelspin was not an issue.

But yes, top mounts are always more impacted by heat (am an Ex-STi owner)

[M4Now!]

Have been doing some testing after the SW update, and mine doesn't feel any different than any other time that the AC is running :

Cheers

[CanAutM3]

I find my M4 rather unaffected by ambient temperature. I was able to hit the highest top speed at my local track on a relatively hot day.

Maybe that Subaru was modded. Or maybe something is off on your car. When is the last time you had your spark plugs replaced? Just before they were due to be changed, my top speed was down by ~5mph on the back straight.

[damnitBobby]

if a subaru out accelerated you then there's something wrong with your car

[AustinTrkJunkie]

Originally Posted by CanAutM3

I find my M4 rather unaffected by ambient temperature. I was able to hit the highest top speed at my local track on a relatively hot day.

Maybe that Subaru was modded. Or maybe something is off on your car. When is the last time you had your spark plugs replaced? Just before they were due to be changed, my top speed was down by ~5mph on the back straight.

My oil minder just dropped from saying 5K until next service to 3K today, think it's time for a dealer visit. For the record, I just popped 5.5K miles...

Thanks all for the replies, def want to get this looked at...

[Nikolas]

Originally Posted by damnitBobby

if a subaru out accelerated you then there's something wrong with your car

Unless of course, it was modded. My old STI would do 0-60 in less than 4 seconds and 1/4 in a 11.2. Some do the same to the Legacy.

[G35POPPEDMYCHERRY]

subby was def modded lol

[HPIA4v2]

Maybe bad gas.
I feel Costco gas octane rating maybe lower than premium brand, not scientific maybe just seat of the pants.

[gatorfast]

Originally Posted by HPIA4v2

Maybe bad gas.
I feel Costco gas octane rating maybe lower than premium brand, not scientific maybe just seat of the pants.

Costco is top tier gas, thus it is a "premium" brand.

[Mikecom32]

Originally Posted by damnitBobby

if a subaru out accelerated you then there's something wrong with your car

Or the Subaru was modded, which is far more likely.

[Venere]

It feels slower because it probably is slower. I'm sure somebody will have a differing point of view, but I doubt that BMWs engineers, wonderful as they are, have managed to rewrite the laws of physics and thermodynamics. An internal combustion engine will have less power when the intake air is warmer and less dense. Intercoolers and charge-air coolers can mitigate that effect, but it's highly unlikely that when the ambient temperature is 100+ degrees that your engine is making as much power as when the ambient is 50 degrees. How much difference and whether you can feel it are open to debate/speculation. But there's gotta be a difference.

[skyline408]

We had a thread like this recently. I'm in the camp of 'my car runs better when it's hot'

Just put it in sport plus, and all the fans kick in.

[AustinTrkJunkie]

Originally Posted by skyline408

We had a thread like this recently. I'm in the camp of 'my car runs better when it's hot'

Just put it in sport plus, and all the fans kick in.

Hah, still scheduling time with my SA, but I run S+ and no DSC all the time(my start up is start, hit M2, DSC off, steering sport, EDC sport+

Some say that's idiotic, me...it keeps me better ready for track days....and my throttle modulation is 4x better

[CanAutM3]

Originally Posted by Venere

It feels slower because it probably is slower. I'm sure somebody will have a differing point of view, but I doubt that BMWs engineers, wonderful as they are, have managed to rewrite the laws of physics and thermodynamics. An internal combustion engine will have less power when the intake air is warmer and less dense. Intercoolers and charge-air coolers can mitigate that effect, but it's highly unlikely that when the ambient temperature is 100+ degrees that your engine is making as much power as when the ambient is 50 degrees. How much difference and whether you can feel it are open to debate/speculation. But there's gotta be a difference.

That statement might be true for "the good ol' days", but it no longer is true with modern FI engines. These engines systems have a fair bit of thermodynamic margin and the ECU will limit boost in good conditions and will compensate with more boost to maintain inlet plenum pressure in poorer conditions and therefore will lose little power.

[rosenbergendo]

It was a heat index of 106 in South Florida and I can guarantee you on a dyno the car is making 5-8% less power compared to a crisp 60 degree day. Its physics.

[Venere]

Originally Posted by CanAutM3

That statement might be true for "the good ol' days", but it no longer is true with modern FI engines. These engines systems have a fair bit of thermodynamic margin and the ECU will limit boost in good conditions and will compensate with more boost to maintain inlet plenum pressure in poorer conditions and therefore will lose little power.

Hmmm, interesting. I hadn't really thought about the ECU adjusting the boost pressure to maintain full power. I was thinking more of my experience with normally aspirated engines ALWAYS feeling more powerful in cooler weather. I still feel like once the ambient gets up to 100 degrees, as it often does here in Texas, the car does feel slower, but who knows if that's really true. Would be very difficult to test on a dyno and keep all the other variables the same. Either way, I sure do like winter in Houston a whole lot better than summer, and so does my car.

[YasM3]

I can see the complaint at the dealer already

"Customer states got beat by a tree hugger Subaru Legacy Lesbo, something must be wrong with vehicle"

[neilum]

Originally Posted by AustinTrkJunkie

This was a roll pushing 80ish to start...so wheelspin was not an issue.

But yes, top mounts are always more impacted by heat (am an Ex-STi owner)

Generally true, but comparing a Subaru "anything" to this car's cooling system and air/water intercooler's efficiency is literally night and day.

If he beat you he is pushing 450+ WHP and has big a big aftermarket turbo, plus fuel mods etc. Or your car is very broken if he is stock or even close to it.

[rakusak]

Originally Posted by neilum

Generally true, but comparing a Subaru "anything" to this car's cooling system and air/water intercooler's efficiency is literally night and day.

If he beat you he is pushing 450+ WHP and has big a big aftermarket turbo, plus fuel mods etc. Or your car is very broken if he is stock or even close to it.

hmm, maybe try a test with another F80? That should narrow the possibilities...

[Jim B]

I haven't noticed that in this 100 degree California heat. It must be the Texas humidity.