Thomas Wiborg

Hello guys!

How does the turbo get affected by cold weather like here in Norway (bellow zero?)
Does the turbo also get affected if its raining / snowing?

I feel that my Turbo looses its boost now in the winter. Ive only seen 0,9bar, but @ summer it run as high as 1,2bar.

Its a 550hp tuned car with K24 turbos.

"02996ttx50

that's odd. i have a similar car and in summer i lose boost and in winter and fog it spikes higher!

which way does water turn going down the drain there? lol

Carlo_Carrera

The colder the air the colder the pressurised charge and the faster your Turbo should be.

Maybe you have an issue with yours?

Thomas Wiborg

Hmmm maybe.

I talked to the tuner of the Porsche, he said it should be running around 1,1 - 1,2 bar.

I only see max 0,9 when i go full throttle in second gear. Is this normal?
Or is there another way to test the boost?

"02996ttx50

yes, choose a higher gear!

leftlane

My car loves the cold weather. I hate it, but the Porsche definitely loves it.

fly2low

^ +1

rmc1148

As said cooler temps better boost/ damp air helps also.

BioBanker

Wild guess - Maybe the computer is pulling back boost/timing because you're running lean in the cold temps?

What octane?

irie1029

-16f & -17f here last few days and seems to have more boost... now that you mention it.

Macster

Assuming tuned car works the same as a stock car in this regard, the DME attempts to satisfy the torque demand of the driver -- as conveyed by the E-Gas pedal signal -- and the DME will allow or restrict boost as necessary to accomplish this.

Under certain conditions I have managed to see only 0.6 bar from my stock 03 Turbo. At other times I've seen 0.7 bar -- the nominal max. amount of boost -- but at other times have managed to see 0.8 bar, even 0.9 bar boost and for long enough to know it was not some kind of "glitch". The 0.8 and 0.9 bar boost occurred at higher elevations. (Which prompts to ask if the boost differences are occurring not only from different temperatures but at different elevations?)

In your car's case, barring a boost/intake leak (or the boost tests being done at different elevations), I would hazard a guess in the cold temps, with little moisture the engine is producing the torque requested without the need for more boost.

At other times, when you see more boost, the DME is having to up the boost to satisfy the torque request.

Thomas Wiborg

I run 98octane. Hmmm. How do you test the boost? As i said, i only saw 0,9 when going full throttle in second. But the tuner said my car should be running 1, 1 - 1, 2, but am i testing the boost the wrong way?

"02996ttx50

what is it with you and second gear? try wot from 2500 rpm in fourth or even fifth. if you don't hit 1.1 or 1.2 and given a moment or two? something isn't right. but your choice of gear(s) will be.

Melb-Mike

Well cold temps means denser air & that means more oxygen. Most ECU's have inlet temp sensor as well as barometric press sensors to allow changes in injector pulse rates to correct the AFR to maximize power. Since the P1 V1= P2 V2 formular is based on absolute 0 or -273 degrees F (0 Kelvin) your baseline changes only amount to about 10% for a 27 deg F change which can result in 5-8% increase in power IF you're ECU is able to effect the change. Basically, lower temps means more power.

Macster

Second that observation you need to try a higher gear. Even with my stock 03 Turbo the engine gains RPMs so quickly in 2nd that seeing nominal max boost (0.7 bar) is hit or miss.

Drive the car in 4th gear at around 2.5K RPMs then with plenty of road nail the gas pedal to the floor and hold it.

This is at best a poor man's boost test. Really, if you suspect the engine is not making the right amount of boost you should have the intake system tested for pressure leaks under positive and negative pressures.

If no leaks are found and if boost is still sub-par you have to look at other possible causes. With a tuned engine one concern I have is with the plugs. They can go away quicker in a tuned engine than they do in a stock engine and they can go rather quickly in a stock engine.

You report running 98 octane gasoline which is good. I hope it is fresh gasoline. Premium gasoline goes stale. There is also the possibility the engine just doesn't like that blend of gasoline. Trying some tanks of another (98 octane) gasoline might be worth considering.

After you are sure there is no intake system pressure leak.