56 replies to this topic

[retro]

Not sure what you want for documentation but I cut a .401 light and ran 119MPH and got beat by Beuf a couple years ago. The motor was getting a little soft after too many runs without a re-cut com. I think the faster guys that day were in the mid to high 120's and most of us were in the mid to high .4's if my memory is correct. This wasn't close to the national record.

The funny thing is it would probably be easy to make more power but trying to get it to hook up would be the hard part.

Thanks -
What I was looking for was voltage applied and source amperage and if possible the amp draw of motor under load.
The "why?" is to try and establish how much amperage is actually being drawn by the super blast type motors - I know what the little 1/32/ womp etc., and some old non winged cars pulled but the power and rpm figures some mention -just appear out of touch with what is possible
If you look at the amp capacity of braid and of the wires to braids etc., you will see what I mean.
I am loking at a solid 12.5 volts as being the power used on these motors
a really good power supply whch will hold 12 volts under 50 amps would deliver , 12x50 which is 600 watts
a ddep cycle marine battery under a 25 amp load looses up to a volt under load
anyway -I would like to know what the input was on the really fast 12 volt stuff -

[idare2bdul]

I saw the 200 amp figure and did kind of wonder but given the fact the car only runs 55 feet under power it's so hot at the end you don't want to touch it for quite awhile. It must be close to pulling what a dead short would be on the track. The 200 amp figure may also be for both lanes. Buena Park has each lane isolated for power as far as I know.

[68Caddy]

Mike that's insane if you ask me, the wiring must be thick as a coat hanger, dead short yes I would agree to that.

Nesta

[Vannerlee]

The faster drag slot tracks are using some big wire, main feeds (both the positive and neg sides) vary fron #4 to #0 multi-strand welding cable. The brade on each lane is tapped into the main feeds with #10 or so wire at 10/12 places. Each lane has it's own 90 amp power supply with 1 or 2 F capacitors. Voltage is well regulated at 16.2 with the power supplys. The guys at Pro Slot told me years ago that the open drag motors would pull close to 250 starting amps from their measurements. Power supplys with caps are up to the challenge. There are still people that think batteries with a charger kicker to get them to 16 volts are the best way but many, if not most, track owners use the powers supplys with no reduction in performance. Battery power is a pain in the butt on long term service.
Lee

[retro]

Thanks - that is the kind of info Iwas after - the wiring sizes and use of caps etc..
The idea of trying to up the output of a 12 volt batt with a 16 v charger is simply - goofy.

the newer power supplies with switching type regs are terrific at constant stable outputs.
itested my Radio Shack 15 amp 13.8 v output powersupply and saw it hold 13.8 volts at a 10 am load -old powersupplies were prone to loose output as they heated.
lead acid batteries are 2 volts per cell -period
with no load a 12v is about 12.5 - on a charger they read up to 14 volts
(cars typically charge at aprox 14 volts BUT under loads you won't see much over the mid 12v.
BIG capacitors will stabilize output for a instant.
In the latest RC crazes of electric powered airplanes and cars , the motors and battery seups exchange huge amounts of power-imagine, a 12 KW motor on a large model
. the instant burst power looked for on drag tracks isn't there but I have personally melted 13ga wires, during in a split second short using a 18volt A123 battery setup -
this is why I really suspect the actual power claims on some drag cars are simply SWAGS.
Last saturday at the local womp race - one car shorted the track for an instant
ALL other 4 cars slowed instantly- yet there was no damage to any equipment or the track.
The reason being that the actual power consumed by these cars is very very small.
I would bet I could power a 4 minute womp race with one 4 cell 2300ma ,A123 battery pack

[don.siegel]

This thread seems to have taken a slightly different twist, but to get back to the original topic...

The other evening, I hooked up a couple 66-67 era motors to my power supply and tached them, using an unidentified tachometer I picked up on ebay UK... you just have to attach a sort of cap with magnet to the shaft and the tach reads that.

Anyway, Cobra 16D with silver wire (about 29 I'd say), on 10 volts and 2 amps max (it didn't like that at first, but finally started running ok, so more would be better):

50,000 to 55,000 rpm

Rx 26D, probably similar wire:
Seemed happier on the 2A max from my power supply. It was also going over the
50,000 rpm mark on about 12 volts, when..

the battery on my tachometer died...

I know these RPM readings don't mean that much for car speed, but you did want to know what the "fastest" motor was...

Don

[CruzinBob]

Ok good stuff..... I remember back in the mid 90's being somewhere where they had a speed gun set-up in the bank and the cars then were hitting 90 actual MPH in the bank....

Gary Cleverley borrowed a gun from someone and used it at various tracks around '93. I believe he had it at the '93 Western States, FlashTrax, Oxnard, CA. I remember Mel Forrest being fastest, hitting just over 90 mph going into the bank. Probably a PK arm in a Camen setup.