warmer weather= better efficency/performance?

[syed123]

Forgive me if this is a stupid question.

From prior belief I have heard diesel engines perform better in the cold.

However I have noticed especially today a massive increase in smoothness and power delivery of my car. I know the weather is warm so my car obv doesn't need to really warm up compared to the cold but does anyone else feel their car performs better in the cold or warm weather?

Syed

 

[desertstorm]

Your prior belief is incorrect on certain points.
From the point of view of mpg and smooth running having run a diesel for the last 10 years I can say that they are much better when the ambient gets above 10-12 degrees. From my experience I would say optimum would be 15-20 degrees.
Over 20 then you start to get a reduction in performance.
All those threads that appear in November about my diesel cars fuel economy has dropped will now be replaced with those people amazed by how many mpg there car is doing.
Winterised diesel should all be through the system now so everybody is back on summer fuel which has a higher cetane content so better running.

Karl.

 

[Gazwould]

Appart from the higher Cetane number , what additives / differences are there between the 2 mixes Karl ?

 

[Leo-RS]

Better efficiency, Yes
Better performance, No

The 2 are polar opposites, you cannot have one without disrupting the other.

The opposite is true when the winter months appear.

 

[cuke2u]

Colder air is better for petrol engines, not sure about diesels...

 

[steeve]

Colder air is more dense so better for internal combustion engines. Better performance and more efficient too.

That's why there are intercoolers on the intake to cool the air, fuel is more dense when its cold too.

 

[mfl]

Yes, try driving any turbo in 30 deg plus Summer temperatures, in heavy traffic, you notice the difference, in both petrol and diesels, although my son's 1.2 Punto diesel would be a bad example, it never had any performance to begin with !

The performance drops off noticeably, one of the reasons why inter-cooler upgrades are popular here among the VAG crowd.
------- even on Golf Rs.

 

[Nikon]

I had three diesel company cars over nine years, VW Bora Sport 130 bhp, 118d 140bhp BMW 1 Series and lastly and the worst a Vauxhall Insigna 160bhp. Combined mileage over 250k yes I can say economy and performance were better better during the warmer months. The VW being the best averaging over 60mpg.