F350 Super Duty vs 3500 Denali vs The Ike Pulling 30k lbs

4x4ord wrote:

ShinerBock wrote:
I think the Ram will be slightly worse than GM's time at around 12:00 minutes. Although I would like to see this test ran in 80F because I have a feeling it would significantly change the time of the Ford while not changing the GM and Ram times too much.

So you're thinking a poor performing turbo was the reason for the Duramax's terrible performance on this run and now you think the Cummins is going to do even worse? Does the Cummins have a turbo issue as well?

It is not so much that I think the Duramax did poor or that it has a turbo issue. It preformed as I would have expected. It is more of a factor that the Ford did better than expected and I have a feeling that it was related to how cool the outside temps. I would like to see how it would perform in warmer weather. This is just a hunch and I could be wrong.

Are you calculating your times based on factory advertised power numbers? If so, then they are way too high. You will need to take off 12-15% for drivetrain lose and more for altitude. The old saying was that turbo chargers loose about 1.5% for every 1,000 ft increase in elevation(gassers loose 3%). However, turbos technology has advanced since this standard and some turbos may loose less of a percentage in power than others depending on their size, blade profile, a/r ratio, and so on. Some turbos may even be able to spin faster than others without reducing reliability like ball bearing turbos over journal bearing turbo bearing. While having a 360 degree thrust bearing does not help in spooling or performance, it does help in longevity of the turbo at high speeds allowing the manufacturer to spin the turbo much faster than they used to without decreasing life expectancy.