question about performance..

[Gr8ful]

Does an engine that has been running for a long period of time lose any performance without cooling down a little?

The reason I ask is because I commute to work which is about 50 miles one way. By the time I get back home and my car has been in stop and go traffic and my engine has been running for a little over an hour and a half it seems like it isn't as peppy as it was when I first started in the morning or drive on the weekend. When I stop at a light or something and try to get a little sporty it just feels 'weaker'. The temperature guage reads in the middle so it's not like its overheated or anything and it's actually pretty cold out.

Is it just me or does the fact that the engine was running for a while have an impact on its performance? Thanks!

 

[sly]

Temperature has a definite affect on turbo charged engines, but normally aspirated engines that aren't overheating shouldn't experience any performance degradation with extended use. The cooler the air, the better the performance, but a heated engine shouldn't lose enough power for you to notice it.

The only thing I can think of and this is a reach, is that your temperature gauge isn't working properly, and maybe your engine is running hot. I doubt that's the case, but if the performance drop is enough to have you concerned, you should have a mechanic check it out next time you are in for service.

 

[jonnyz16]

I would think it'd run alittle better with the engine up to operating temp.It could just be your imagination? If it bugs you enough take it to the dealer Gr8ful..

 

[epj3]

I can tell you exactly what happens, and I noticed it with our minivan. If you would drive on a highway at 75 mph for 20 minutes and got off on an exit, it would feel like it has a lot of power, versus driving in traffic for 20 minutes, flooring it and having it not feel too powerful.

What happens is your ECU (Car's engine control unit) improves the fuel air mixture to make the engine run as economic and smooth as possible on highways. Then in stop and go, you really need low end torque, not higher RPM torque since you rarely hit higher rpm's.

Hope it made a little bit of sense.

I actually dont notice this with my 325is.

 

[donmbmw]

After 50 miles of stop and go traffic I would want out of the car so bad that unless it was a nitro burning dragster it couldn't get me home fast enough.

 

[MrElussive]

Yeah, I think the ECU just adjusts the engine's timing to improve fuel economy since you were just sitting in traffic. But once you get back to normal driving, the performance should come back...perhaps try putting it in Sport Mode once you want the power back. The ECU should then immediately make the engine work harder.

 

[Ghost]

I agree the ECU, plus the carbon build up that needs to be burned during the time you were stuck in traffic. Which is why driving on the expressway is good for the car. The fun doesn’t start ‘till you break the 3500rpm mark.