Bob Tom <tigers@bserv.com> wrote:
: At 01:29 PM 2/7/05, you wrote:
:>--SNIP--
:>Anyhoo, my brain went "does not compute" on me; there's probably a
:>simple explanation, but I had to check. I'm assuming the numbers
:>weren't a typo, so are the DragTruk times out of date perhaps? I
:>would have expected 13.70s out of a 4300-4400lb truck at that power
:>level. -Jon-
: I've been a little puzzled myself after seeing lots of very impressive peak
: numbers on all the Dakota forums with higher than expected ETs.
: I know that the shape of the power/torque curves and where the peaks occur
: are more important in projecting likely ETs than the actual peak numbers alone.
: "Area under the curve" to ex-Math teachers :-)
Good point. Now that I think about it, that "engine master challenge"
they have in Popular Hot Rodding (I think?) uses power under the curve to
calculate the winner. Probably a "peaky" motor without a nice broad
torque curve underneath it won't be able to achieve the same ETs.
Plus, there is probably more technique involved in driving a vehicle
like that, to be sure you time the shifts just right and don't fall off
the power curve - freight train torque may act something like a safety
net. :-)
[...]
: Going to drag radials many, many years ago from my all-season Dunlops
: gave me a 3/10th drop.
Yep, IIRC, Bill Tierney had about the same results with the DOT tires
on his Dak. I might have been able to go to the low 14s instead of mid
14s with a line lock (so that I could heat the tires properly) but after
tearing the spider gears out once, I resigned myself to stickng with the
street tires. Fortunately my 60' times were pretty decent, I think, for
a street tire. My best time was 2.08 using 235/70R15 Firestone Firehawks
at about 20-25psi. The one time I borrowed Bill's DOTs, the short time
was 2.05, but I wasn't able to spin them enough to make them effective;
you're supposed to do a burnout until you see just a whisp of smoke
coming off them, but when I tried that with my non-line-locked 5 speed,
it would just launch the truck instead of spinning the tires. :-)
: Where I've found to be invaluable about dynos. is that it's a pretty good guide
: in seeing/confirming where improvements are needed so that you have
: a pretty accurate idea what mod is needed next for improvement and
: whether it will complement your existing mods. That's just been my
: experiences.
Sounds right to me. Since there is so much possible variance, probably
also a good idea to use the same dyno, same dyno operator, attach it
the same way each time, etc. if at all possible.
: The best mod for our trucks which have the aerodynamics of a shopping mall
: is a huge tailwind :-P
Heh! :-)
--
-Jon-
.-- Jon Steiger ---- jon@dakota-truck.net or jon@jonsteiger.com --.
| 1970 Barracuda - 1990 Dakota 'vert - 1992 Ram 4x4 - 1996 Dakota |
| 1996 Intruder 1400 - 1996 Kolb FireFly - 2001 Ram QC 3500 CTD |
`------------------------------------ http://www.jonsteiger.com --'
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