make a difference in speed?

I changed them last week at 40k miles and then in the area that I use for a quick sprint, the car hit 135 instead of the 127 which it had hit many previous times.

The only other difference was a 10 degree (F) temperature drop, from 72 down to 62. I'm under the impression that turbo cars are not as temp sensitive as s/c'd cars or even NA cars.

They definitely smoothed acceleration on the low side of the band.

 

TC cars are extremely sensitive to temp changes. The more air a car takes in, the more sensitive it is to the density and moisture content of that air.

 

No, it wasn't the DVs unless the stock ones were leaking under boost (and that is doubtful). It was the cold air. Turbocharged vehicles (as well as s/c ones) benefit more from colder ambient temps than n/a cars.

 

If he had 40k on the stock diverter valves, I would be that he was leaking boost (if he went from the stock to aftermarket).

Mine started leaking at 10k, so when I put in my Baileys, I immediately noticed a difference as I was back to holding stock boost.

 

100% correct. Colder air is more dense and packed with more oxygen. A boosted car (turbo or supercharged) reacts better to colded air. Not to mention that intercoolers (if your car has them) become more efficient at cooling the air charge before it enters your throttle body.

 

Well the combination of new Baileys and 49 degree air helped me to glimpse .9 last night on an otherwise stock engine.

One of the few benefits of winter.

 

Oddly enough, I find that I boost LOWER in the winter as the charge is already so cold and compressed, I do not need to boost as high in order to obtain the proper air/fuel ratio.

 

I wonder if the added boost in my case is due to the gas mix in DFW during ther winter?
We have a special summer blend using MBTE that's supposed to benefit air pollution (less) - it actually works against air quality and the law has been changed to eliminate it sometime in the next 2 or 3 years. (Private imdustry tries to correct mistakes immediately, the government ... depends on how powerful the special interests are.)

 

You wouldn't get higher boost unless the octane rating of the gas increased for the most part. Higher octane advances the timing and also the boost a small bit until knock is sensed (I am guessing that the Porsche ECU has a learning curve like this...)

 

DFW911T - I took my car out and briefly hit 0.8 bar in 6th gear today (from perhaps 2900-3100pm or so). It was about 46' outside when I did this.