Advancing a Cam

Frederic Breitwieser frederic.breitwieser at xephic.dynip.com
Fri Mar 27 15:48:37 GMT 1998


>Now I know that this will result in loss at high end, probably peak
>torque will move down the rev range please could someone confirm this?

This is true, within reason, and your high-end will suffer.

>The crux of the matter is this:  I am gonna run my engine at 7.5:1 as I
>want to run silly ammounts of boost.  To help eliminate lag, I was

I will be running 10:1 c/r with silly amounts of boost, utilizing
water/alky injection to cool the inside of the cylinders, a fluid-based
intercooler, with freezer coils in the fluid storage tank.  The piston
bottoms will be sprayed with oil jets, as to cool the underside of the
piston as well.  I'm hoping all of the above will result in a really good
system.

If you don't hear from me in about 2 months, that means I blew up with my
engine :)

>thinking of running a whole load of ignition advance, and advancing the
>cam to give me a tractable ammount of low end off boost.  No I know that
>a gain in one area comes with a fall in another... so what pit fall am I
>going to get here?

Running too much advance on the cam does introduce really lousy mileage,
I'm not engine savvy enough to know why, but on a friend's engine we
advanced the cam as far as we could and have it still idle, but we had to
move the idle up to about 850 from 550-600 ish, not exactly sure of the
figures.  After a month, he reset the cam back to the normal position since
idle was horrible, and highway mileage was significantly awful.  This was
on a naturally aspirated 350 which he opted to turbocharge instead.

>Is the engine going to get upset with the cam timing and refuse to rev
>above a certain level? or is there something I just cannot see yet?

His engine, with the cam ahead (again, I don't recall how far ahead), it
wouldn't go above 4500 RPM without sounding like something was going to
explode.  Again, I'm unsure of the figure, but I remember the sound!

He also moved the cam really far, I remember the aggrevation trying to move
it that far ahead.


Frederic Breitwieser
Bridgeport, CT 06606

Homebrew Automotive Website:
http://www.xephic.dynip.com/

1993 Supercharged Lincoln Continental
1989 HMMWV
2000 Buick-Powered Mid-Engined Sports Car




More information about the Diy_efi mailing list