Thread: cam timing
View Single Post
Old 01-21-2011, 08:35 PM   #1 (permalink)
arcosine
Master Ecomadman
 
arcosine's Avatar
 
Join Date: Nov 2010
Location: Chicago area
Posts: 1,154

sc1 - '98 saturn sc1
Team Saturn
90 day: 43.17 mpg (US)

Airplane Bike - '11 home built Carp line Tour

rans - '97 rans tailwind

tractor - '66 International Cub cadet 129

2002 Space Odyssey - '02 Honda Odyssey EX-L
90 day: 28.25 mpg (US)

red bug - '00 VW beetle TDI

big tractor - '66 ford 3400

red vw - '00 VW new beetle TDI
90 day: 58.42 mpg (US)

RV - '88 Winnebago LeSharo
90 day: 16.67 mpg (US)
Thanks: 20
Thanked 337 Times in 227 Posts
cam timing

I am sure this topic has been hashed around, but for a single cam engine:

Which would get better mpg, advancing cam timing or retarding cam timing.

Advancing cam timing will make the engine have the lowest brake specific fuel consumption at a lower rpm, so one can drive in a higher gear.

Retarding the cam timing will cause some of the mixture to be pushed back into the intake manifold, thus lowering the pumping losses. The exhaust valve opens later, thus providing some extra force on the piston.

It seems to me that for lugging around town, an advanced setting would be better and for highway a retarded setting would be better.

Anyone have experience?

__________________
- Tony

  Reply With Quote