If UNDERdrive pulleys are so great, why aren't they factory/OEM?

[Bob Ayers]

My background is in Off-highway applications, which do require testing at WOT, and don't really apply here. ).

Why would the EPA require WOT emission testing for Off-highway, but no WOT emission testing for On-highway?

 

[krugford]

Well, when you're running a combine through the field, you're spending a lot of time at full load rated speed. (15-20 hrs/day). The standard 8-mode test was a way to apply the same standard across multiple engine applications such as tractors, combines, 4 wheel loaders, excavators, etc. New emissions testing is requiring a transient analysis in addition to the standard steady state testing. As for light duty on highway, I don't know why it wouldn't be required....

 

[red2003xlt]

As for my original statement that sparked the comment on emissions in the first place, I find it to be true. Emissions is the biggest loser when it comes to the aftermarket power/fuel economy tradeoff. IMO, it's also one of the biggest reasons that cars are getting more sophisticated while gas mileage is staying the same or dropping. Tighter emissions controls require more fuel because in the long run, all you're doing is trading the more harmful emissions (PM, NOx) for the less harmful ones (CO2).

I gotta disagree on one point. Every time engines guys up the horsepower and efficiency. The design guys up the fat (curb weight).

My 2003 LWB is a porker at nearly 4000lbs. My buddies 1986 LWB was right at 3200 lbs.

Not limited to the Ranger, my 1971 F-100 hits the scales at 4400 (it's pure steel) The 2008 F-150 is closer to 6000lbs.

I'd lay money down my F-100 could out pull it.