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3/08/2011 8:18 am  #1

gearing for a ps-101 big block

I have been playing with my first Big Block 20 for about 2 months of weekly racing and the only thing I have learned seem to be no two are the same,one racer gears his at 8-60 another at 12-56 same tires same track both quicker than mine, I started at 12-58 then 12-60 still no better than 1.1 Sec.next dropped the pinion to a 10th which at 10-60 has the lexan funny car body a consistant .999-.990 ,I know it will be quicker with either a 62th spur or trying a 8 or 9 th pinion ,but what a .990 index car so try a 10-60 if that does not work drop to a 8 or 9th pinon then you have the option of 8-58 or 8-60 wich will allow the timing to kick in a diffrent points down track,seems to make little diffrance for some reason on 60Ft. times , good luck,have fun       These are runs on a 1/4 mile,16.1 track Volts, 10-60 gearing, WRP side winder with .082 stainless tubing, long Funny Car wheel base, 1 3/16th x.500 JDS tires,Koford drag glue regular.

Last edited by davidRevans (3/09/2011 7:02 am)


6/04/2011 4:47 pm  #2

Re: gearing for a ps-101 big block

Hope you found the right gearing for your Big Block 20 , I just went to a 9th pinon 60 th spur from a 10 th 60 spur and the car/motor fell on it's face ,hard to belive one tooth on the pinion could make such a diffrence...going to have Ken W. freshen it up with a Comm. turn and zap the magnets , new brushes and see if that helps me out


6/04/2011 7:48 pm  #3

Re: gearing for a ps-101 big block

You are right about them all being a little different. I start at 12/58 on mine and adjust from there. by the way, I ran to different rails last night with BB-550. One ran in the .850 range (12/58) and the other in the 8.60 range(12/56). These are 1/4 mile times. Seems like the older they get the more gear you have to through at them.


6/07/2011 4:39 pm  #4

Re: gearing for a ps-101 big block

Ask Vito who loves these motors will tell you the best gearing to start with is 11/56-58.  I have one in a slip joint and I geared it with what I had at the time which was 12/62 and the thing runs consistent .900 in the 1/4 and have made several passes on the juice at .887!


6/07/2011 5:41 pm  #5

Re: gearing for a ps-101 big block

Marty I think its mostly in the mags.


6/07/2011 8:38 pm  #6

Re: gearing for a ps-101 big block

Slip-joint Dragsters LOVE the BIG BLOCK 20  Could very well be the Magnets from motor to motor... I got a slow one

Up date 7-3-11 Had Ken W. freshen up the Big Block 20 Comm. turned -Magnets Zapped - new brushes and shunt wires, made it's first outing at Down river , Still geared 9 - 60 1 3/16 X 500 ,back into lexan funny car at 110 grams ,track was running on an old road course power supply since the drag strips was stolen so it only had 14Volts and 50 Amps to work with ,managed to run it's best times ever at .962 and .967 at 61 Mph ,new power supply to arrive middle of week  can't wait to run it on 16 Volts and some serious amps..

Last edited by davidRevans (7/06/2011 3:45 am)


6/08/2011 4:36 pm  #7

Re: gearing for a ps-101 big block

Most come mistake is gearing these motors to make big 60 foot times.  They like to wind up on the top end and if you gear it to launch fast they are over reving the motor.  I have seen arms delaminate from over doing it.


6/08/2011 4:38 pm  #8

Re: gearing for a ps-101 big block

Meant to say common mistake.


6/08/2011 5:33 pm  #9

Re: gearing for a ps-101 big block

I think most people are not using these for what they are intended. They are not made to leave hard. If you want better 60' buy a 20. Or better yet build a neo.  Most that i have had are in dragsters and run in the mid .8 range geared between 12-54 to 58.


7/12/2011 4:01 am  #10

Re: gearing for a ps-101 big block

Magnets on the Big Block 20 ,Get them Zapped ...mine was struggling to stay around 10 flat got feed up took it and had Ken W. Zapp the magnets, true the comm. put it back in the car .967 first pass .969 the next , hoping to have it settle into .990's.

Geared at 9-60 now 60Ft times 1560-80 but hang on from 660 to finnish!

Last edited by davidRevans (7/12/2011 4:05 am)


7/15/2011 7:39 am  #11

Re: gearing for a ps-101 big block

The Pro slot Big Block 20 is a diffrent animal from most , essentually a hybrid ; D can with a larger diameter arm but wound with 20 wire , with the 1 3/16 tires quickest  0-60ft is .15's but where their wild is from 660 to the finish , if there is no glue down track, be prepard to spin the tires,you can over glue and bog them down off the line easily ,just to have them spin rest of the way down the track , once you figure out what your set up likes ,nobody will run you down the secound half of the track..problem is I have yet to find racers using them have the same gear ratios these motors are individual...and if you try to gear for a quick 60Ft they will go up in pieces after a few rounds Glad for the experiance it has given me as it is the first motor that has gotten me faster than .990 showed a lot on aero effect and in-line and angle winder chassis . had this motor first geared 12 - 56 lot of Mph no E.t. then 12-58 same results them 10-58 helped E.T. but still in 1.0's and the car became unstable .switched to Funny car body and angle winder Chassis car still unsettled added 1/4 inch rear spoiler,then car ran smooth , dropped 10 -60 better E.T still a lot of Mph (74) so went to 9 - 60 E.T. now setteled to .970 - .990 range and 64 -67 Mph . not the fastest out there of the Big Blocks but when the rest of your cars run 12 to 2 it is quick enough


7/15/2011 4:31 pm  #12

Re: gearing for a ps-101 big block

These big blocks should not go lower than an 11 pinion.  Everyone has these motors screaming at the top end and wonder why it flew apart?  I have a rail geared 12/60 and runs 890's at 75 mph on a track that is ok.  If I get that rail on a smooth great powered track it might go 860's!!!!  Give up on trying to hit low 60'  and gear it for the top end!  They will be much more consistent and faster.


7/16/2011 5:58 am  #13

Re: gearing for a ps-101 big block

Weastcocoakid ,funny car weighs in at 115 grams ,and I run 1 3/16 X .500 wide JDS rear wheels WRP angle winder tall tire chassis ,no ball bearings., .082 rails, WRP Dodge Avenger F/C lexan body 1/4" high spoiler.


1/30/2012 6:30 pm  #14

Re: gearing for a ps-101 big block

Ok I am new here I drag raced slot cars about twenty years ago,and our local track closed down. There is a new local track that I just started running at, my question is how would you gear a ps101 for 1/8 mile track? I have a older drs chassis wedge dragster @ 96 grams 1.0625x300 pro track tires. This past weekend I had several passes mid 56s three runs were over 60mph my gearing was 14/50. could I lower my et by possibly going to a 11 or 12/50? Without over revving the motor?


1/30/2012 6:45 pm  #15

Re: gearing for a ps-101 big block

I gear em at 11/56 for the 1/4 so for the 1/8th I would go 10/56?  Not to familiar with running 1/8th


2/21/2012 3:54 pm  #16

Re: gearing for a ps-101 big block

I've been .90's with a big block that had the arm rebalanced, com trued and mags zapped in a 115 gram hardbody 2002 Vette with a 10/58 gear. Same car with a 66 Nova body at 123 grams is now going .96's consistently with a best of .943


2/21/2012 4:30 pm  #17

Re: gearing for a ps-101 big block

In pro outlaw those guys have these bigblocks running in a hardbody 125 gram car in the mid to low .8's!


2/21/2012 4:37 pm  #18

Re: gearing for a ps-101 big block

For the 1/8th mile I would start at 9 /58, I run the 1/4 mile with mine geared there and get a good 60 ft. time  breking the tires loose if there is no down track glue at about the 1000ft sensor ,using 1 3/16th tires so might want 9/56 with the smaller tires..have not found a big block 20 geared the same for any two racers , have to keep changing gears till you find what works for ,tires ,chassis , and body it is setting in..


2/21/2012 4:55 pm  #19

Re: gearing for a ps-101 big block

To run that gearing they glue the whole track for pro outlaw just to get the 60 ft numbers.


2/21/2012 6:25 pm  #20

Re: gearing for a ps-101 big block

Well over the last Sunday my big block slowed down alot. The weekend before I posted a .588 1/8 mile ET which was low ET of the meet xtra bonus points for our points we run. This sunday it could only get it to run .650s at best . So I decided to revamp the car, the wedge body was getting ragged pin holes ripping etc. so it tore the car apart cut the body down and installed it on a chassis that is alot shorter. It now weighs 63grams with the big block added some more gear final ratio with tires figured in is a 3.91 it was 3.33. bought a new Booth wedge dragster body very thin and have it on the chassis ready for another ps4021 bb neo motor  .
Ill have to wait til sunday to play with it, its our monthly $100 to win race.


2/24/2012 6:01 am  #21

Re: gearing for a ps-101 big block

might just be full of glue spray and gunk ,have you tried holding it over some paper towels and sqiurting the insides with lighter fluid giving it a good rinse out , try it off and run it on a power supply low voltage to dry it out further, if you get to heavy on the endbell bushing oil it can also gum up the brushse an comm. , flush the axle bearings the get cummed up also..just something to try...


8/24/2012 4:57 pm  #22

Re: gearing for a ps-101 big block

I have a big block in a 125g hard body 1x1/16x500
geared it 10/58 and it ran 1.00 @51 first pass
ran it again .987 again @51 let it cool off
and just for the hell of it kept the 10 pinion
and went down to a 48 gear and it ran a .975 @58.95
so the next time out I will run a 11/56-58 and see
where that goes I think I am close with that set up
thanks for all the help.



8/26/2012 10:42 pm  #23

Re: gearing for a ps-101 big block


Step the gear up....  For me, they run best geared 11/60,62....  Rotate the endbell counterclockwise (looking at the endbell straight on)....  It takes a touch of glue to hook, but it really comes on hard from mid track!



4/04/2013 7:04 pm  #24

Re: gearing for a ps-101 big block

I am just guessing but with that weight ,and a 1/8th mile ,I would run a 10 th pinion and start with a 56Th crown if using 1 1/16th tires , big blocks launch soft and their is less space to get it's rpms..Your weight is a Killer , can you remove some plastic from inside the body or remove any added weight to the chassis ?


11/06/2015 7:11 am  #25

Re: gearing for a ps-101 big block

Good info here on the 550 Big Block. Saved me a good bit of trial and error by finding this post.


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