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Old 03-22-2012, 09:22 PM   #1
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Default RJ Speed Funny Car gear ratios ???

Had a 3.5 BL motor sitting on the workbench....and it needed a better home, so I put together, a RJ Speed Funny Car.

Have not run it yet.....I'll update when I do.

Currently, I have it set up with an 18T pinion, 81T Spur (48 Pitch) for a final drive ratio of 4.5:1 on the 3.5 Brushless.

(Overall tire height, is about the same as standard touring car tires....but wider)

Anyone else have experience with this car? What gear ratio/motor combos have you tried?

Thanks!

P.S. Post some pics!
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Old 03-23-2012, 04:02 PM   #2
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The surplus workbench guts:
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Old 03-23-2012, 04:29 PM   #3
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I run my RJ Speed Funny car with a FDR of 3.4ish with a 5T motor. Pretty much, as long as it is not hot after 3 seconds its under geared, but also, you want to make sure you are making max rpm before the end of the track, even somewhere about 1/2 track would be better.
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Old 03-23-2012, 09:31 PM   #4
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The stock RJ tires are very hard so you are limited on how much power you can put down.

A solid set up would look like this

Spur: 98
Pinion: 16-18
Motor timing: full
ESC timing: 20 degrees
RPM range: 15,000 - 25,000 rpm

You also would be better to move the batteries as far forward as possible.

Good Luck and let me know if I can help.
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Old 03-23-2012, 09:43 PM   #5
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You also would be better to move the batteries as far forward as possible.

Good Luck and let me know if I can help.
Yeah, this is good advice, i use 800mha lipos and have then sitting on the front wheels. Remember, that a pass is only a couple of seconds, so, you do not need to take an hours worth of power with you, but just enough to get the job done, those little lipo are good for 4 or 5 passes then i change packs.
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Old 03-23-2012, 09:48 PM   #6
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I myself wouldn't run anything under 3000 mah in a 2-3 cell car but if you are only running in a parking lot or street that is not prepared (sprayed with VHT or sugar water)then the lack of traction will relieve the huge load the cells would have to endure so I imagine you can get away with it.

I do like the idea of a smaller mah cell to soften the launch something a funny car needs badly.
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Old 04-14-2012, 07:12 PM   #7
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Default RJ Speed Pro Mod Nitro

Have more spare parts on the workbench....so this NovaRossi Race .12 is going to see some action in a Pro Mod dragster.

More pics as it gets completed.
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Old 05-19-2012, 04:29 PM   #8
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Default RJ Speed Pro Mod and Funny Car

Took both cars for a short run....(no pun intended)
Here are some pictures:
A few handling problems I still have to sort out......
Both cars pull hard donuts when I get on the power.
I set up a straight edge along the rear wheels to check the front axles, and I think the main reason they pull hard to the side, was my front toe was off.
I'm hoping I got them set up right, as tomorrow is the speed run jam.
We will see.
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RJ Speed Funny Car gear ratios ???-promod-body-.jpg   RJ Speed Funny Car gear ratios ???-promod-3-4th-rear.jpg   RJ Speed Funny Car gear ratios ???-promod-body-off.jpg   RJ Speed Funny Car gear ratios ???-funny-1.jpg  
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Old 05-19-2012, 04:36 PM   #9
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Kept blowing one O-ring tire off the same side on the promod, and had to feather in some steering wheel input on the funny car when under speed.....
Those signs are telling me, front toe is very sensitive to set up (especially since they are spooled)
Glued the O-rings on too.
Anyone that has had bugs, and worked them out, please chime in!
And post your pictures too!
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Old 06-26-2012, 10:06 AM   #10
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I have been wanting one of these for a while. Any more updates or photos?
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Old 06-26-2012, 11:51 AM   #11
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Originally Posted by y2kgtp View Post
I have been wanting one of these for a while. Any more updates or photos?
Can't put the power down, without it spinning donuts.
Hit about 30mph on the radar gun, but that's at 25% throttle, open the throttle, and same thing happens....
As I only built this for my local hobby shop's annual parking lot jam, My car is now for sale
My nitro ProMod is also for sale.


Don't have time to figure out the do-nut thing.....probably just a set up issue.??
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Old 06-26-2012, 12:45 PM   #12
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Quote:
Originally Posted by red7fifty View Post
Can't put the power down, without it spinning donuts.
Hit about 30mph on the radar gun, but that's at 25% throttle, open the throttle, and same thing happens....
As I only built this for my local hobby shop's annual parking lot jam, My car is now for sale
My nitro ProMod is also for sale.


Don't have time to figure out the do-nut thing.....probably just a set up issue.??
I think most tracks spray sugar water or VHT to get the foams to hook up. Otherwise it will just spin around.
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Old 07-09-2012, 07:34 AM   #13
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Quote:
Originally Posted by red7fifty View Post
Can't put the power down, without it spinning donuts.
Hit about 30mph on the radar gun, but that's at 25% throttle, open the throttle, and same thing happens....
As I only built this for my local hobby shop's annual parking lot jam, My car is now for sale
My nitro ProMod is also for sale.


Don't have time to figure out the do-nut thing.....probably just a set up issue.??
I got one of these in the mail the other day. After looking at how the rear hubs go on the shaft......did you grind some flat spots for the set screws to grab onto?

I can't see how you can put any real power into this and expect to get a plastic hub held in place with setscrews on a smooth shaft not to slip.
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Old 07-09-2012, 04:54 PM   #14
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Quote:
Originally Posted by y2kgtp View Post
I got one of these in the mail the other day. After looking at how the rear hubs go on the shaft......did you grind some flat spots for the set screws to grab onto?

I can't see how you can put any real power into this and expect to get a plastic hub held in place with setscrews on a smooth shaft not to slip.
Yep, ground 4 flat spots.
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Old 03-13-2016, 06:42 AM   #15
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Default 55 Chevy

Quote:
Originally Posted by red7fifty View Post
Can't put the power down, without it spinning donuts.
Hit about 30mph on the radar gun, but that's at 25% throttle, open the throttle, and same thing happens....
As I only built this for my local hobby shop's annual parking lot jam, My car is now for sale
My nitro ProMod is also for sale.


Don't have time to figure out the do-nut thing.....probably just a set up issue.??
Hi , is the 55 still for sale ? I'd like to buy it ? Thanks john
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