Dave; I have read your message three times. I can not find one thing in
it I disagree with.
Doug Odom in big ditch
dahlgren wrote:
>
> 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
>
> The Butters Family wrote:
> >
> > Well sort of your Pro stocker would have to be able to leave the line in
> > high gear and you would have to be able to run with the throttle wide open
> > for max. engine efficiency, neither of which are going to happen. Believe
> > Kieths car showed the increased speed because he was able to run with a
> > whole lot less wheel spin. First of all we are talking about speed at a
> > given distance, matching final gear ratio to the cars power will determine
> > ultimate top speed of course. My theory is that speed at distance is
> > determined by the total power available to do the job. With gearing you
> > can change your et, even cut your terminal velocity with two short of gears
> > but have little effect on how fast you are going at any given point. If your
> > street car has a stick shift go out and run it between two points as hard
> > as you can using all the gears, then do it in say second and high, your
> > speed should be nearly identical. The only explanation I have for this
> > is that even though the et was muuuch slower the motor was able to do the
> > same amount of work. While you would think blitzing threw the HP peak
> > several times would gain speed, apparently chugging threw it builds the same
> > speedOriginal Message ----- Well thats my story, my car is a 53 stude
> > running a hemi BB/cc with a 3 speed TF, I'm sure it would be just as fast
> > with direct drive and a push to 60mph, wheel spin is a big problem. Hope
> > theis helps let you know where I am comming from. Best regards, Kvach
> > From: dahlgren <dahlgren@uconect.net>
> > To: The Butters Family <bbutters@dmi.net>
> > Cc: Marge and/or Dave Thomssen <mdthom@radiks.net>; Land-speed Racers
> > <land-speed@autox.team.net>
> > Sent: Monday, August 28, 2000 1:22 PM
> > Subject: Re: Bonneville Transmissions
> >
> > > So if I understand this right then... If I put my pro stock car in 4th
> > > and leave the starting line that that at the end of the quarter mile the
> > > car will go the same speed as if i used all the gears?? When you lose 5
> > > mph at the quarter does your car go the same speed at the 5 as if you
> > > were not 5 mph down?? Why do all the 'big' streamliners keep wanting a
> > > longer course ??? How fast does your car or cars you have messed with go
> > > ??? I am sure that if I start in any gear that my Pontiac i drive on the
> > > street will go exactly the same speed at the 5 no matter what gear I
> > > start in.. but going 125 is not much of a challenge either. How do
> > > explain away the change of shift points in Keith Turks car making 203 at
> > > the 3 instead of 197 at the 5???? Doesn't having the correct gearing and
> > > going as fast as soon as possible make the course appear to be longer
> > > because you are going faster sooner and have more distance left to get
> > > the last MPH out of the car??
> > >
> > > to quote "We got a 225 record with 183cid 3rd gear only??? Nebulous"
> > >
> > > Is this the theory you are using?? Do you think the 225 might of been a
> > > 245 with all gears working??
> > >
> > > well we got a 216 record 219 qualifying with a 91cid gas lakester and
> > > went 213 at the 1/4... used all 5 gears.. which one is more efficient
> > > ??? and that was on the first pass.... Do you think if we left in high
> > > gear that the car would of gone 219 at the 5 on 91 inches ??? What's the
> > > physics behind your theory??
> > >
> > > Oh yeah and the e-mail you quote.. what's that thing doing on the long
> > > course at 179 if you should be going over 175 at the quarter in the
> > > first place???
> > >
> > > Hate to make this sound like a flame but I really can't figure out the
> > > logic behind it all.. Help me be smarter and tell me how this is all
> > > supposed to make sense..
> > > A very confused engineer..
> > > Dave Dahlgren
> > >
> > >
> > > The Butters Family wrote:
> > > >
> > > > This has been my experience with every car I've ever
> > messed
> > > > with, the speed it was able to generate in a given distance hadnothing
> > to
> > > > do with the number of gears you shifted it threw, just the power it had
> > > > available to do the job. Kvach----- Original Message -----
> > > > From: Marge and/or Dave Thomssen <mdthom@radiks.net>
> > > > To: Land-speed Racers <land-speed@autox.team.net>
> > > > Sent: Sunday, August 27, 2000 7:35 PM
> > > > Subject: Bonneville Transmissions
> > > >
> > > > > Well, gang our experience might be interesting. In 1979 we ran the
> > > > Original
> > > > > Goldenrod streamliner (the one from Denver) with my flathead (unblown
> > on
> > > > > gas) and a T-10 4 speed. It ran 179 MPH in the last mile and we
> > thought
> > > > the
> > > > > gear spread was just right for the motor until something malfunctioned
> > in
> > > > > the transmission and it locked in high gear. We pushed it off as fast
> > as
> > > > we
> > > > > could (60Mph) and it chugged off barely able to pull away from the
> > push
> > > > > truck. The quarter time and the 2 and the 3 mile were slow, but it ran
> > > > > 179MPH in the last mile anyway. Anyone have similar experience that
> > might
> > > > > suggest that a long course car doesn't need a transmission at all?
> > > > >
> > > > > Dave the Hayseed
> > > > >
> > > > >
> > > > >
> > > > >
> > >
|