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Old 12-29-2007, 09:55 PM   #5 (permalink)
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FarFarfrumpumpen - '03 Volkswagen Jetta Wagon GLS Premium

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Originally Posted by MetroMPG View Post
And I have read (maybe you can confirm or correct me) that diesel powered vehicles are even better suited to aero mods than gas SI engines. As you decrease load on a gas motor by helping it move through the air more cleanly, it needs less "throttle". Unfortunately closing the throttle probably also has the effect of shifting the operating range further away from the ideal BSFC zone.

My understanding is that because diesels don't have throttle plate restrictions and the associated pumping losses of SI engines, reducing engine load through streamlining will give a diesel car a larger relative return in efficiency.
I have no Idea about aeromodding Diesel vs Aero modding gassers Interesting I hope someone knows more about this topic.

I'd also like any info about pulse and glide with a diesel, I'm having difficulty trying to find an optimal throttle to pulse at. To much and I spool the turbo (lots of fuel), to little and I end up with similar -> worse mpg than the cruise.

Originally Posted by MetroMPG View Post

What about gearing - do you know if you have any options there? (I put a taller final drive in my car, which helps most at cruise on the highway).
We do have a few gear options available to us I can't remember the ratios at the moment, but there are 3 "upgraded" 5th gears for my trans, or swap in a 6 speed (but that's a pricey option)

I am not "dead Set" on driving 70, my reason for driving 70 is that I get within 2mpg any speed for 58~71 mph (turbo starts working at 58ish) and under 58 is just to slow for me on the interstate, If I could do 62~65mph @ 50mpg I'd do it. For reference I get 65~70mpg at 55mph. and 100~120mpg @ 40mph

I don't do a lot of highway driving, but when I do it is usually in a bit of a rush; Typically have to pick up a sick 2 year old 75 miles away from me.

If anyone can't understand my post just speak up and I'll try and clarify.
2012 Tesla Model S P85
2013 Nissan LEAF SV totaled by now deceased intoxacated driver.
2012 Nissan LEAF SV
6 speed ALH TDI Swapped in to a 2003 Jetta Wagon
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