View Single Post
Old 09-12-2012, 04:57 AM   #21 (permalink)
oil pan 4
Corporate imperialist
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,266

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
Quote:
Originally Posted by Diesel_Dave View Post
Diesels typically aren't as optimized for reduced pumping losses (high VE) as you might think. In typical spark-ignited naturally aspirated gassers, high VE is pretty much the only way to get more torque at any given speed. So if you want to get more torque you pretty much have to increase the VE. On a diesel however, you can just add a little more fuel and/or a little more boost and you'll get the torque. Sure the FE will be sub-optimal, but it's just so much easier than redesigning heads and intakes.
It just goes to show you how well the efficiency concept of a combined cycle intercooled turbodiesel engine works.
They started off real efficient and cranked out amazing power levels with out much added complexity or engineering.
Fuel economy didn't matter much as diesels could beat their gas fuelled counterparts with ease in head to head tests and on top of that diesel fuel was quite a bit cheaper than gas until about 10 years ago.
But times are changing and with diesel fuel prices projected to soon rocket past $4/gal in the U.S., adaptations need to be made.

__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote