I've been wondering how to interpret that 25% engine setback in the
rulebook. If the wheelbase is 100", to achieve a 25% setback, is the
motor set back 25" from it's original location, or is the 25% based on
some other measurement, such as length of the motor or something. What
I've been planning is to position my bucket seat where I want it
(probably 1" forward of the rear axle) then move the engine and trans
back until I have just enough room to feel comfortable with my feet and
pedals. I havn't gotten around to actually doing this yet, but it
looks like that will be with the motor set back around 30" from it's
stock location. I'm then going to remove, move, and fabricate cross
members accordingly (I'm using an S-10 frame.) I also have a '49 Ford
truck frame I could use. I picked the S-10 because it has pretty good,
modern, suspension and ride, with disc brakes already installed, and I
was originally going to build a multi-purpose street/race car - but now
I'm building strictly for LSR race. Looking at all the pictures I
could find in old magazines, I've toyed with the idea of using the old
Ford frame instead and building it with the beam front axle and without
any suspension at either end. What guidance can you guys give me on
this?
Thanks,
Dick J
--- "Ferguson, Darrell" <dfergus@bactc.com> wrote:
> Ron Pruett who runs the Pretty Lady AA/GCC - AA/GALT
> T-bird has his motor
> set back 25% and I have been told that there is a
> video of him going through
> the traps at Bonneville, and when he lets off, the
> car goes sideways about
> 20 degrees. I don't know how heavily his car is
> ballasted, or what his
> weight distribution is, but it sounds like he might
> need some more ballast
> up front. Again I think it goes back to last weeks
> discussion, concerning
> weight distribution, polar moment of inertia, center
> of gravity,
> aerodynamics, and how every car is different. Trial
> and error is the only
> way to find out. I've been criticized for not
> setting the engine back enough
> in our car, but we've got lots of ballast ahead of
> the rear axle so we'll
> find out. We made it easy to adjust our weight
> distribution so we can remove
> up to 600 lbs. off the rear and add up to 250 lbs.
> up front, plus we can
> adjust the rear spoiler, and front airdam, so we
> have lots of tunability to
> hopefully get it right. I'd suggest leaving yourself
> the ability to add or
> subtract weight off of both ends.
>
> Darrell Ferguson
> BLACK RADON ENGINEERING
> # 939 BBFALT
> http://my.cybersoup.com/blackradon
>
> > -----Original Message-----
> > From: richard jurkowski [SMTP:lsr_man@yahoo.com]
> > Sent: Tuesday, June 22, 1999 4:11 PM
> > To: John Beckett
> > Cc: land-speed@autox.team.net
> > Subject: Re: Handling & Weight - another question
> >
> >
> > I've been away for four days, and already I'm lost
> and confused. Last
> > week we were talking about my in-progress C/GCC,
> and i was talking
> > about shoving the motor back abour 20 - 30 inches.
> I was then going to
> > mount the battery in the back and the fuel tank
> along side. Now i hear
> > you saying to move the weight forward to stop a
> camaro from wandering.
> > I guess I've been thinking NHRA too long. Should
> i get the motor back
> > as far as I can, or only far enough to meet rules
> and get the car as
> > low as i can? Should the other stuff like fuel
> and battery go in the
> > rear or in front?
> > thanks,
> > Dick J
>
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