I simply don't understand using an Automatic.... Sorry Doug... ain't that I
don't love your car... .. When you have limeted Ponies why waste them on the
Auto?
With the in and Out box I understand they can be effiecent.... but with a
Torque converter all that is Lost....
SOOOOOO lets evaluate how to stick a Four speed in your car for a sec....(
bare with me on this even if your not interested ) First the Clutch linkage
is a NON issue with the advent of Hydraulic Throw out bearings.... ( 150 or
so ) and you already have Brakes so sicking another pedal in isn't that much
of an issue.... especially with the Floor Mounted stuff out there....again
about 100- 150 dollars.... Okay now we are up to a Clutch.... Tilton Two and
Three disc Clutches are avalible from Muscle Motorsports Used for about 200
bucks apiece....
Okay now are up to the Bell Housing.... well.... you already have it set up
for something... Ford and they make those for around 200..... Fly wheels are
going to be interesting... but they are sure doable I am sure....
Okay finally we get to the Trans itself.... Again Muscle sells rebuilt
T-10's ( Stage Three.... Nascar Stuff... good to 750 hp ) for around
1500.... and Gear selection is absolutely selectable even down to a 2:43
first 165 second and a 118 Third....
So on the end of the day Doug.... Personally I would go down this Road....
and Not have an Auto..... Besides.... God wants us to Shift Race cars....
Keith.... ( just food for thought Doug )
----- Original Message -----
From: <ARDUNDOUG@aol.com>
To: <land-speed@autox.team.net>
Sent: Saturday, August 26, 2000 10:53 AM
Subject: Ford C-4 Tranny Gear Deliberations
> Group,
> Attached is some correspondence with a new found crew member we met at
> the KOA at Speed Week. Elon is a middle aged drag racer who has taught
high
> school auto shop in the past and is now an engineer at the Lawrence
Livermore
> Labs in Livermore, CA (10 miles from my home). He had flown his Cessna 172
to
> Wendover Intnl. on Sunday and hitchiked to the KOA, lucked out by renting
one
> of their cabins, and was walking through the campground when he saw the
extra
> Ardun/Flatty in the push truck.
> In the ensuing conversation we offered him daily transportation to and
> from the salt, but he would have to get up at 4:30AM to take advantage of
the
> ride since we were in Impound a couple of mornings in a row. He ended up
> "hanging-out" with our motley crew, hopefully getting hooked on salt.
> One of our ongoing deliberations during the meet was the RPM drop we
were
> experiencing on our shifts with the C-4 in the Ardun/Flatty powered
Modified
> Roadster. The stock C-4 ratios of 2.46/1.46 were causing the motor to drop
> about 2600RPM on the 1-2 shift and about 2000RPM on the 2-3 shift. The
nitro
> would pull the revs back up pretty quickly on the long course but on the
> gas-passes (pardon the pun) the motor needed closer gears. My feeling was
> that the car could benefit in general from closer ratios. I did some
research
> and found that alternative ratios of down to 2:1 low gears and 1.33:1
second
> gears are available although pricey ($850-$1300 for the low and second
gear
> sets).
> Any of you using or contemplating the use of the C-4 tranny in an LSR
car
> might find the following interesting.................Ardun Doug King (1313
> XX/FMR)
> <<
> Hi Doug:
>
> Actually, I think the 2-3 shift with the NEW gears is a 23% drop
> (1/1.3 = 0.769) which I am assuming (depending on the cam) is even
> better than the 25% drop you mentioned. That means that if you make
> the 2-3 shift at 6500 RPM the motor will drop to only 5,000 RPM for
> that final, long pull. Mike forwarded me your narrative and you
indicated
> that the
> gas motor had a tough time pulling the taller gear when Brian was
> qualifying. With the 23% drop you just might be able to pull that
> taller gear on gas since the motor will be starting the 2-3 pull much
> higher up on the RPM curve (5,000) and not down around 4,500. It all
> depends on the cam and you have the best feel for that.
> ##############
> It might pull the taller gear on gas with a closer ratio setup in the
> C-4. You're right, the drop 1-2 with the 2.0:1 first gear will be 34.5%
> (1.33/2.00) as opposed to 40.7% (1.46/2.46) as it is now. The drop 2-3
with
> the 1.33:1 second gear should be 24.8% as opposed to the 31.5% as it is
now.
> With the present setup it drops to about 3860RPM 1-2 and to about 4450RPM
2-3
> using the stock 2.46:1 first gear and the 1.46:1 second gear. With the
2.0:1
> low gear and the 1.33:1 second gear I figure that it'll drop to 4320RPM on
> the 1-2 shift (1.33/2.00) and to about 4900RPM on the 2-3 shift
(1.0/1.33).
> Please check my math out and let me know what you think.
> ################
>
> I don't know how hard the top-end pull was on the nitro motor but I
> think you indicated that you pulled off before the 5 mile. So I would
> guess that the closer ratio 2-3 shift, would let the nitro motor pull
> a slightly taller gear also. I really, don't know because it all
> depends on the cam... and you know that better than anyone. The other
> alternative is that the closer ratio may let you experiment with a
> more narrow-band cam.
> ################
> The motor seems happiest from 5000RPM to 6500RPM+. As I recall, John
DeLong
> said that cams power band started somewhere around 3500, but with these
> little engines it feels best to me above 4500RPM. I have several DeLong
cams
> that I'd like to stick with in the short term. When John died all his
> machinery and cam masters went to Rod Furtado, the Flatty machinist in San
> Jose. Jim Stevens (the guy next to us in impound with the 165MPH Flatty
> street roadster) has some ideas for a mushroom lifter cam next year. I'll
> probably try his ideas then.
> #####################
> Another thing to consider (but I don't know much about) is that I have
> heard that nitro builds a lot of heat in a motor. If you start the
> 2-3 pull at a higher 5,000 rpm with a slightly taller gear you will
> have been producing more horsepower over a longer period of time
> ...building a lot more heat. You may need to consider your cooling tank
> capacity.
> ######################
> The aluminum Ardun heads dissipate(sp?) a lot of heat. As it is I run a
195
> deg. thermostat and that does the job pretty well, indicating 200 deg. at
the
> end of the long-course.
> #####################
> Do you think the taller 1st gear will may cause a problem? The higher
> starting gear will put a greater demand on the converter (building
> heat) or loading up the engine?
> ########################
> I have a tranny cooler under the tonneau cover and right aft of the
coolant
> tank. Since the aerodynamic resistance in low gear will be much less than
in
> second and high, plus the fact that it's a fairly tight converter, I feel
> that I'll be OK on tranny temp also.
> #########################
> Another question. What was the final gear you were using on the 208
> mph run? I have been playing with a few numbers and with a 28" dia
> tire at 6,500 rpm and 208 MPH I get a ratio of 2.6 : 1. (assuming NO
> SLIPPAGE or any kind in either the converter or the tires). But I
> thought you were running a 2.48 : 1.
> ##########################
> We had a 2.48:1 gear in the Quickie on the fuel runs and Brians 179 pass
with
> 28.5" Goodyear Funny Car fronts. Ed Weldon did a chart for me with the
> different ratio's RPM's, and percent slippages. The 208-210 at 6500 with
2.5%
> slippage was really close to what we actually did. The final gas pass was
> with a 2.7 gear in the Quickie.
> #########################
>
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