hey racing is all one big hill LOL.. See there is nothing new and most pieces of
common sense apply..
Dave
William T Smith wrote:
>
> Aaaahhh as a glimmer goes on in the almost empty head
> cavity..
> A Shift Chart--- we do those all the time when spec.
> trucks to graph what you said about staying on the high
> side of peak touque-- as you fall back up the torque
> curve we call that Torque Rise.
>
> This is very helpful because this determines a
> vechicles ability to acclerate in that gear or to
> maintain speed on a hill. wmts
>
> Quoting Dave Dahlgren <ddahlgren@snet.net>:
>
> > Well in the copy you sent back in your reply the
> letters after 8500 seem to
> > be
> > goofy. They did have the new rpm if you made the
> shift at 8500 rpm. The
> > torque
> > will come out close to what you have as the rpm goes
> down the torque goes
> > up. It
> > is all full throttle stuff. I use Ft/lbs at the rear
> wheel to do the gear
> > splits.. HP is a calculated # torque is what the
> parts really see.
> > Dave
> >
> > William T Smith wrote:
> > >
> > > Dave,
> > > I don't understand Point 2
> > > How can the wheel power be close to the same as you
> go
> > > up the gear shifts when your mechanical advantage
> drops
> > > so much with each shift. Is it because you dont
> have to
> > > use full throtle to get the RPMs?
> > > Also what were you giving an example of when your
> put
> > > the trans ratios. what were the .625 .7 .785 was
> this
> > > the percentage of total torque reflect by the part
> > > throttle?
> > >
> > > Quoting Dave Dahlgren <ddahlgren@snet.net>:
> > >
> > > > Wide or close ratio has a lot to due with the
> power
> > > curve of your engine.
> > > > there
> > > > have to be a bunch of e-mails about this in the
> past
> > > too as i remember the
> > > > discussion well. i was the guy with no clue about
> > > what really works(at
> > > > least the
> > > > was the opinion of the old salts as i remember it
> > > anyway). When i work on
> > > > gear
> > > > splits what i try to do is this.
> > > > Launch the car as quickly as possible so as to not
> > > waste any track length
> > > > at the
> > > > start.
> > > > each gear change should result in 3 things
> happening
> > > if possible and less
> > > > important in the lower gears.
> > > > The first and most important is that the new gear
> > > selected is still above
> > > > the
> > > > torque peak of the engine. This is so if you have
> > > trouble making the gear
> > > > change
> > > > or have to peddle the car and lose some RPM you
> are
> > > falling back into the
> > > > peak
> > > > and not away from it. This will insure that you
> will
> > > hopefully have the
> > > > power to
> > > > pull the next gear if there is a problem.
> > > >
> > > > The second is to have the new gear selected to
> have
> > > the same amount of
> > > > ft/lbs on
> > > > the rear tires as the previous one. You can do
> this
> > > if you have a dyno
> > > > sheet for
> > > > the engine. This will ensure 2 things happening.
> > > first you will not have
> > > > any
> > > > problem pulling the next gear up as the power at
> the
> > > wheels is the same as
> > > > it
> > > > was. second you will not shock the tires and lose
> > > traction.
> > > >
> > > > To do this right depends on the torque curve of
> the
> > > engine and whether it
> > > > has
> > > > nitrous or not and when you turn the nitrous on
> if it
> > > has it.
> > > >
> > > > For a typical N/A car with 300 inches i would
> shoot
> > > for 5 or 6 gears.
> > > > something like
> > > > assuming peak power at 8000 rpm
> > > > 1 3.2
> > > > 2 2.0 .625 X 8500S13
> > > > 3 1.4 .7 X 8500Y50
> > > > 4 1.1 .785 X 8500f73
> > > > 5 1.0 .91 X 8500w35
> > > > with this you should be in 5 'th about 1/4 mile
> > > before the mile of interest
> > > > and exit that mile at 8500 to 8800 rpm..
> > > >
> > > > My opinion and your mileage may vary.
> > > >
> > > >
> > > > Bill & Dee Bennett wrote:
> > > > >
> > > > > Ok somebody explain to me why with having a
> longer
> > > distance to run at
> > > > > Bonneville using a close ratio transmission is
> > > better. I realize that
> > > > you
> > > > > might experience to low a drop in rpm in the
> gear
> > > changes using a wide
> > > > > ratio. Is this the reason why or is it something
> > > else. I would have
> > > > thought
> > > > > the 6 speed would be a good choice for the salt
> > > given the ability to
> > > > space
> > > > > the ratios over 5 speeds and using 6th for
> > > overdrive. If close ratios are
> > > > > what are needed why not the something similar to
> > > the old style Doug Nash
> > > > > tranny with 5th being 1:1 and no overdrive. If
> > > horsepower lose is the
> > > > deal,
> > > > > I don't think that matters to a few as already
> > > stated over the past few
> > > > > weeks. It seems to be no problem building the
> power
> > > it is getting the
> > > > > traction to use it.
> > > > >
> > > > > Bill
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