Yokomo MR-4 TC Thread
02-20-2002, 07:18 PM
#1246
Sorry Josh, my bad.
The first batch of "Silent" belts was rumoured to be slightly different from the ones later included in the SP kits.
Part of my mistake was that I bought a whole pile of goodies to put on the car when I did the upgrade.
I find that the torque rod pulls the tail of the chassis up, thus loosening the front belt(It moves the entire rear gearbox slightly up/forward).
If you look at the tiny gap between the motor plate and rear bulkhead, you'll see that the gap at the bottom is greater than the one on the top, basically the rear of the chassis is flexed upwards/forwards slightly.
You will also need to file the rear of the topdeck slightly so that the lug machined into the gearbox housing(for the extra motor plate screw on the PRO and WORLDS car)won't stop you adjusting the torque rod past a set point.
Just have to check tweak to make sure everything is hunky-dory and you're off.
The first batch of "Silent" belts was rumoured to be slightly different from the ones later included in the SP kits.
Part of my mistake was that I bought a whole pile of goodies to put on the car when I did the upgrade.
I find that the torque rod pulls the tail of the chassis up, thus loosening the front belt(It moves the entire rear gearbox slightly up/forward).
If you look at the tiny gap between the motor plate and rear bulkhead, you'll see that the gap at the bottom is greater than the one on the top, basically the rear of the chassis is flexed upwards/forwards slightly.
You will also need to file the rear of the topdeck slightly so that the lug machined into the gearbox housing(for the extra motor plate screw on the PRO and WORLDS car)won't stop you adjusting the torque rod past a set point.
Just have to check tweak to make sure everything is hunky-dory and you're off.
02-20-2002, 08:02 PM
#1247
Different as in better, or wear out faster?
So with the torque rod you get more antisquat, do you like it that way?
Speedo
So with the torque rod you get more antisquat, do you like it that way?
Speedo
02-21-2002, 05:21 PM
#1248
Since it's the very tail of the car flexing, if there was any anti squat there before, it'd be gone now. Seems OK, I just pedal it around as fast as possible.
The "different belt" thing is just gossip at the moment, I know that batch variations exist in many things, just as likely to be the belts too. Rumour was that the belts were slightly too tight in the first batch.
Anyone see the new diff bearings on the Yokomo JP site yet? Each bearing now has 13 balls in the race, old ones had 9.
Part number BB-1510P
The "different belt" thing is just gossip at the moment, I know that batch variations exist in many things, just as likely to be the belts too. Rumour was that the belts were slightly too tight in the first batch.
Anyone see the new diff bearings on the Yokomo JP site yet? Each bearing now has 13 balls in the race, old ones had 9.
Part number BB-1510P
Last edited by Simon K; 02-21-2002 at 05:23 PM.
02-21-2002, 06:39 PM
#1249
So do you make the rod longer, or shorter?
02-21-2002, 07:33 PM
#1250
Tech Adept
Well, I was making the rod longer - tightening the front belt - d'oh!
I just assumed ("assumption is the mother of all foul ups") that when people said they were using the torque rod (aka "belt tensioner") it was to tighten the belt. I was trying to get more throttle punch. Results were minimal: noticed an improvement for the first couple of battery packs then the belts were stretching.
Gotta' adjust for the chassis tweak, too.
I've only tried this on the Pro where you need to remove the screw that attaches the rear bulkhead to the motor mount and loosen the screws that attach the upper deck to the rear bulkhead. Otherwise, you've got opposite forces on the upper deck.
Pretty sure there was no effect on the tension of the rear belt; the layshaft and rear diff are enclosed in the rear bulkhead.
Optimizing belt performance and wear is pretty tricky for the assuming.
YJ
I just assumed ("assumption is the mother of all foul ups") that when people said they were using the torque rod (aka "belt tensioner") it was to tighten the belt. I was trying to get more throttle punch. Results were minimal: noticed an improvement for the first couple of battery packs then the belts were stretching.
Gotta' adjust for the chassis tweak, too.
I've only tried this on the Pro where you need to remove the screw that attaches the rear bulkhead to the motor mount and loosen the screws that attach the upper deck to the rear bulkhead. Otherwise, you've got opposite forces on the upper deck.
Pretty sure there was no effect on the tension of the rear belt; the layshaft and rear diff are enclosed in the rear bulkhead.
Optimizing belt performance and wear is pretty tricky for the assuming.
YJ
02-22-2002, 05:01 AM
#1251
Originally posted by yokomojo
Here's my calcs:
lbs/inch Grams/3mm
Yok-Black 9.69 519.00
Yok-White10.47 561.00
Yok-Blue 11.03 591.00
AE-Green 12.00 642.89
Yok-Yellow12.88 690.00
Yok-Pink 13.12 703.00
Yok-Green13.78 738.00
AE-Silver 14.50 776.82
AE-Blue 17.00 910.76
Yok-Orange17.71 949.00
AE-Gold 19.50 1044.69
AE-Red 22.00 1178.63
AE-Copper25.00 1339.35
Here's my calcs:
lbs/inch Grams/3mm
Yok-Black 9.69 519.00
Yok-White10.47 561.00
Yok-Blue 11.03 591.00
AE-Green 12.00 642.89
Yok-Yellow12.88 690.00
Yok-Pink 13.12 703.00
Yok-Green13.78 738.00
AE-Silver 14.50 776.82
AE-Blue 17.00 910.76
Yok-Orange17.71 949.00
AE-Gold 19.50 1044.69
AE-Red 22.00 1178.63
AE-Copper25.00 1339.35
02-22-2002, 07:43 AM
#1252
They must be GT4 springs, because for one the MR-4 springs don't come with lb rates, and I have measured the MR-4 springs, the green springs are 19lb, not 40. The MR-4 springs are flouescant, the GT4 ones are a bit dull, and I'm guessing that's what you have.
Speedo
Speedo
02-22-2002, 10:10 AM
#1255
Mo- have you tried the new thin Yok firm inserts? I ran Pit 30-27 with the thin firm at the Snowbirds race and they were awesome. Now that was with the suspension mods and a little tuning help from Chris. He was nice enough to stop by my pit and hang out a little to help me fine tune the car. I really wanted to try the thin mediums but they didn't have any. One note- I ended up lengthening the front shocks to like 61.3 because they were "sprung" to use Chris' words. Preloaded is what he meant. Anyway, that took away the slight "loose" feeling in the rear and my car was planted! I think the sorex' might have had a tad more side bite, but the pits/yok combo made the car soooo easy to drive.
Have you tried the long shock ends in the front with that set up yet? It seems they might work better because right now there looks to be too many threads showing on the shaft. I was thinking maybe try cutting that lip off the top of the long shock end to make sure there is enough up travel. I'll try it on our local p/l race Sunday....
If any rich people are reading this, PLEASE come to Memphis and open an indoor carpet track!!!! I love carpet!! Either that or send me the capital to open one....
Have you tried the long shock ends in the front with that set up yet? It seems they might work better because right now there looks to be too many threads showing on the shaft. I was thinking maybe try cutting that lip off the top of the long shock end to make sure there is enough up travel. I'll try it on our local p/l race Sunday....
If any rich people are reading this, PLEASE come to Memphis and open an indoor carpet track!!!! I love carpet!! Either that or send me the capital to open one....
02-22-2002, 10:23 AM
#1256
I haven't tried the new inserts yet. The only tire/insert I will be running untill after the Carpet nats is the TO 27's, and then there will be no more carpet around until next winter. I don't use the long shock ends because I think the shortest you can get the shocks is about 64mm with them.
02-22-2002, 10:26 AM
#1257
Oh OK- I didn't realize that was the shortest you could get them... I don't think I've ever tried them. Oh well. I just worry about not having enough threads in the shock end and popping the shaft out. You know us "not so perfect" drivers have to think about durability!! LOL 
02-22-2002, 03:04 PM
#1258
Chassis comparison & setup
I'm running the MR4TC with the worlds chassis?? (its the one before the special conversion) What I'm curious about is how do the 2 chassis compare.... the Special vs Worlds?
I forget the oil weight but right now I have orange springs, shocks are 59mm, ride height 5mm. BAll diff front & rear. The car is a blast to drive and does have a hint of push, but it's managable.
If I convert to the special, what is the setup for it... on Parking lot tracks like Castle, Sheldons.... I also race at Delta when I can.
Thanks
Rich
I forget the oil weight but right now I have orange springs, shocks are 59mm, ride height 5mm. BAll diff front & rear. The car is a blast to drive and does have a hint of push, but it's managable.
If I convert to the special, what is the setup for it... on Parking lot tracks like Castle, Sheldons.... I also race at Delta when I can.
Thanks
Rich
02-22-2002, 03:22 PM
#1259
To get rid of that push, lengthen your front shocks to, say, 60mm. This should give you a bit more, you could go out to 61 also.
Ths special is quite a bit lighter and the slightly different drivetrain runs the belts right down the center. It also centers the weight more so the car can react faster.
Speedo
Ths special is quite a bit lighter and the slightly different drivetrain runs the belts right down the center. It also centers the weight more so the car can react faster.
Speedo