Don't know if this proves Dave's point or not. Based on the data I have
collected over the years I did some math, well a lot of math and this is
what I come up with:
Trying to keep everything constant: Drag, HP, Rear Gear, Tire size, Optimum
Gear Ratios, No Overdrives, Shift Points, Polar Moments of Inertia, etc.,
this is what I found.
6-speed transmission gave me the fastest speed at the end of 5 Miles.
5-speed was .1 MPH slower.
4-speed was .2 MPH slower.
3-speed was .7 MPH slower - try getting optimum ratios for a 3-speed.
2-speed was 1.2 MPH slower.
Powerglide w/ no torque converter was 2.4 MPH slower.
T-400 w/ no torque converter was 4.7 MPH slower.
T-400 with torque converter was 11.7 MPH slower.
Don't have any info on a Lenco, but suspect it's similar to the T-400.
Probably not the big numbers some were looking for but given different
vehicles, HP, Traction, the fact that I was keeping many things constant,
and this is math only, I think the results may actually be greater. Also the
difference in MPH between the 6-speed and the 4-speed may not have you
rushing out to plop down the extra three, four or five grand for one either.
But if you want the ultimate!
John Beckett, LSR #79, E/FCC
----- Original Message -----
From: "dahlgren" <dahlgren@uconect.net>
To: "The Butters Family" <bbutters@dmi.net>
Cc: <Land-speed@autox.team.net>
Sent: Wednesday, August 30, 2000 8:43 AM
Subject: Re: Bonneville Transmissions
> I don't mean to flame or harass on this issue but I find it very
> interesting and a core subject to the sport of land speed racing. So
> please don't take any of it the wrong way hopefully...This is long and
> may beg for the 'delete' key so be warned..
>
> if a theory is correct it works no matter what the variables are.. So i
> did go out and put my car in second ..drove 100 feet a valid distance in
> my mind .. with the engine floored it was much slower than using 1'st
> and second....car weighs 2500 lbs has about 150 hp and 170 ft lbs
> torque..traction was not a problem in either case
> I think your theory if it is going to work has to have unlimited
> distance.. Acceleration does matter because if you are going faster
> sooner then you have more distance left to achieve the peak velocity. By
> the way the long course in my mind is only 4 miles long in the first
> place because the only way to reach the highest AVERAGE speed over a
> mile is to have the entry and exit speeds be as fast as the car will go.
> A good example would be a car that enters the final mile at 250 and
> exits at 275.. if I put more gear in the car it will accelerate to a
> greater speed at the entrance because you have the is gearing advantage
> for the whole 4 mile previous and will only go slightly slower at the
> exit speed..I have been doing this since 1991 at bonneville and it works
> every time.. the downside is 1 it is harder on the engine(more rpm) to a
> small degree and 2 the driver hates the zero G input to the car and
> complains about it seeming to float.. The downside to not using a
> transmission are 1 it wastes valuable real estate waiting for the car to
> get up to speed. 2 if there is any problem with the run there is not
> enough distance to ever recover 3 it is very very hard on the bearings
> to lug the engine down to a very low rpm and apply full load. it is also
> very hard on the pistons for several reasons the most being if you have
> a carb the main jets have no picked up yet and the engine will be very
> lean and the high egts will hurt the engine (burned piston)..If you have
> mechanical injection the engine will surely be fat and take a while to
> clear out if it does not wash the rings out..If you have EFI and it is
> tuned right the air fuel ratio will be good but now you are making even
> more power on the slow turning crank and beating the bearings to death..
> I really hate to blow my own horn.. but i have been racing
> professionally since around 1975 24 hrs daytona Nascar winston cup
> nascar Modified Bush cars..Drag races.. fastest car shootouts..won
> zillions of races / championships / manufacturer titles / pole
> positions..etc To be real candid if you went to every event held at
> bonneville and set a record at every one i suspect you have still not
> won enough....I am semi retired now as the pressure of all that every
> day was too much for me but did learn so many tough lessons that they
> are not forgotten.. I still consult, manufacture some parts that always
> seem to end up on winning cars and travel around doing tune up work and
> new product design for other companies. Do yourself a favor just for
> laughs. Try it my way and see if you car is faster...what is to hurt by
> running a different gear ratio for one pass or running the engine up in
> rpm and keeping it in the power peak for a full pass???? If it is so
> fragile that it can't stand the rpm then fix it...
> At what RPM does your car make peak power?? peak torque??? In all my
> years i have never seen a car that did not go faster with more torque at
> the rear wheels, though i have seen many cars with suspension that was
> incapable of transmitting the power(fixable) and have seen drivers that
> would not drive and apply the torque sensibly(replaceable) and have seen
> tires that would not hook up(selected wrong) and have seen cars that
> were hopelessly constructed wrong(disposable).
>
> If you know the HP and torque #'s for your engine and the appropriate
> rpm,very valuable info, and your car is still accelerating beyond the
> last measured mile I am willing to bet you that if you work on the
> gearing and shift points the car will go faster than it does now. will
> the peak speed be greater?? maybe , maybe not.. is there a record for
> exit speed?? not that i am aware of.. to attain peak speed in most cases
> the car has to run about 5 to 8% beyond the rpm for peak power through
> the entire timed distance and not be able to go very much faster at the
> 5 than it does at the 4 for the highest average speed. you should be
> right at the wall when you have no more power left to overcome the aero
> drag and rolling resistance with the engine is up to speed... If the car
> is not getting light then adding weight is worse than adding more tire
> to get the bite to this this because the rolling penalties are less than
> the inertia problems associated with the weight. You should be racing
> the lightest car that does not want to fly.. I would think that anything
> in the /CC classes can have any suspension they want. There are many
> designs that will apply torque very softly to the tires and allow them
> to hook up with small g loadings and do not rely on a great deal of
> weight transfer. If spinning the tires is a problem i would look at the
> suspension and tires way before taking power out of the car by running
> the engine in high gear only.......
>
> my opinion for what it is worth or not...but a real good topic to kick
> around..
> Dahlgren
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