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**DONOTDELETE**
02-27-2002, 03:08 PM
Hi Adam. It is the duration that makes an engine run "lumpy". The lift you are describing is a trade off. I know you want the lift to let the head breathe but the valves have to return to their seats. Half an inch is GIGANTIC lift. I think it may not be such a concern when running a midrange engine with moderate duration,but high rpm engines have to have heavier springs to hold the valves to the cam profile. If you are running a ported head and bigger valves, you may want a cam with more duration ie. 272 is plenty , and slightly less lift .425 or something. Just my opinion. Often the full race cams have less lift than a street cam, but they have 300 degree duration and idle at about 2000rpm.hahaha.
What RPM are you trying to run at??
Rob

**DONOTDELETE**
02-27-2002, 03:20 PM
Originally posted by ADAM H:
i am getting a custom turbo cam ground and need some input....
looking for lots of lift so ..450-500 lift...
duration...short...maybe 270?<font size="2" face="Verdana, Arial[/img]Are you looking for a cam to work in conjunction with a turbo? Big cams are not good for turbo applications. I think the term is "blowby" or something. When the intake is pressurized, some of your air and fuel will go right out the exhaust valves before combusting. This results in poor fuel economy as well as loss of power.

**DONOTDELETE**
02-27-2002, 05:24 PM
isnt that overlap that your talking bout? I thought it was good only for some NA cars, like this snooty little GSR in the driveway =(

ADAM HUTCHINSON
02-28-2002, 12:45 AM
i am getting a custom turbo cam ground and need some input....
looking for lots of lift so ..450-500 lift...
duration...short...maybe 270?

any input?

anyone?

so i am looking for....top end power.....no LUMPY cam..i have been there done that....is it the lift or duration that makes the cam lumpy?

reason..sohc head is not flowing well (enough)at high rpm..so this cam is going to be working in conjunction with
1mm oversize stainless valves..and a big hogged out port job on the sohc head...

ADAM HUTCHINSON
02-28-2002, 05:30 AM
hi rob,

yeah i plan to run new springs...rpm i want to run at is 6800-7000, my last cam (took it out..its in a box now) was a .500 lift and 300 duration cam....very very lumpy.....

i am looking for more top end power...that last cam i had..pulled right to 6800 rpm....