It really can't amount to more than a 1 atmosphere change. I would suspect what
happens is the oiling system has problems to be honest. First you have negative
g loadings and the oil goes to the front of the pan and then there is none for
the bearings or anything else yet you are still at high rpm. The rod small end
is usually lubed with splash if there is no splash then there is a problem the
big ends also have a problem too. I think when you close the throttle slowly you
eliminate the negative G loading and the problem goes away but not for the
reason you think. yes closing them slow with a wet sump pan might be a good idea
but the failure and cure have nothing to do with the real problem that caused
the failure. Every time I have a failure of any part the first thing I try to do
is find out the forces on the whole car and not start by focusing on the
individual part that failed. As a case in point there have been many failures i
have seen in con rods in short track stock cars. Would always break a rod when
really going for it and braking deeper into the corners. This was in the days of
wet sump oiling, now that they are all dry sump this has become a pretty rare
thing in comparison. It was all g loading related nothing to do with throttle
position. You really have to look at the big picture to start.
Dave Dahlgren
"Thomas E. Bryant" wrote:
>
> Dave,
>
> Give it some thought.. every engine cycle there is exhaust stroke with no real
> pressure above the piston so you are still in the unsafe condition you
>describe
> for 50% or the time.
> I believe it would be more accurate to say reduced pressure 50% of the
> time, moving the exhaust out requires some engergy. Closed throttle
> creates a vacuum which, in my opinion, changes the pressures above the
> piston drastically. Just a thought!
>
> Tom, Redding CA - #216 D/GCC
>
> Dave Dahlgren wrote:
>
> > Your theory or Surtee's theory would be valid if there were no exhaust
>stroke..
> > Give it some thought.. every engine cycle there is exhaust stroke with no
>real
> > pressure above the piston so you are still in the unsafe condition you
>describe
> > for 50% or the time. As far as making it easier to drive with high gear
>only..
> > My answer is get another driver that will deal with it, the car will go much
> > faster with a transmission in it. The funny thing about being the best is
>that
> > you are the best relative to everyone else at the time, and your methods
>are the
> > best at the time you used them. That does not mean that better ways to do
>things
> > will not come along or better drivers and engines. It is all relative to the
> > date the records is set. It makes it all fun to see things evolve and you
>need
> > to grow with the new information. This does not ever discount what someone
>has
> > done in the past but does allow for growth and new thinking. Oh and you dare
> > wrong on the over rev in a sporty car.. they bang those things off the
>limiter
> > endlessly..and we do get errors on occasion that they have exceeded the
>limiter
> > by 8 or 9 hundred rpm in a set of tight corners with lots of downshifts..
>Some
> > of these are engines with the limiter set at 9000 or more rpm also.
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