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#1
21-07-2016
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SV2 diff advice
Hi all,
I am racing a SV2 on very high grip carpet. Overall it goes well considering it was not specifically designed to race on this type of surface unlike a KF. Its major weakness seems to be the ball diff, they don't seem to have the longevity, and once they slip, the balls are wrecked.... For example, I checked my diff before the last race I had Tuesday, absolutely fine, slipper clutch moving not diff. After the race, click click click, crunch crunch crunch   I am in two minds whether to throw in the towel and get a KF with a gear diff or spend some ££ on a Schumacher pro diff which I would hope would be stronger and better able to take the punishment over a sustained period of time.... I am torn on which way to go to be honest, so if anyone can confirm that a properly setup pro diff can take the punishment on the highest of grips levels I would appreciate it. PS - thank goodness for gear diffs - I absolutely hate ball diffs I am sorry to say to the purists....  Thanks Adrian 
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#2
21-07-2016
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new diff screw (and bolt) needed maybe??
__________________
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#4
21-07-2016
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I raced the SV2 for 2/3 seasons and never had any problems with the diffs, rebuilding them every 4/5 race meetings. Do you run the diff tight enough, using the locking grub screw to ensure it doesn't come loose? From memory, I used to back it off 1/8th of a turn once assembled.
Also, are you running the diff with the main diff screw on the left hand side of the car? (left hand being the non drive side) I always found them very reliable, and only ever ran ball diffs in my KF2. In my opinion they just feel nicer to dive, and offer more consistent grip.
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#5
21-07-2016
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Quote:
 I think I'm going to rebuild it pro diff spec, but rather than back it off 90 degrees once I feel the springs compress, I am going leave it like this. I think as soon as they start slipping, they're doomed, and in a race full of other cars you cannot hear it - just find it knackered at the end of the race...  I race on extremely grippy carpet, and with these modern torque-y motors, its really struggling to take the punishment.. :-s at least the standard diff.. 4-5 race meetings between rebuilds - probably why I hate the things 
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#6
21-07-2016
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I'd still back it off just a touch if possible, if not 1/8 of a turn, maybe 1/16th? I think if you left it compressed, you'd just ruin the plates and the balls from the diff being too tight. Most of the time I only rebuild the diff for the sake of it, they can go longer without rebuilds, especially indoors with no sand or dust!
I'd make sure the slipper is set properly also, to prevent the car from wheelie-ing using full throttle from a stand standing start. A newly built diff will also 'break in' during the first 3 or 4 runs, so I always double check the tightness after each run to make sure it isn't working loose. Hopefully these pointers will give you a little more luck with them and you'll be good to go
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#7
22-07-2016
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Quote:
I think the issues I am having with this diff, just highlights the mega torque & power these new brushless motors put out, as back in the 90s I don't actually remember servicing any of my Schumacher diffs once built!
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#8
22-07-2016
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Hi Adrian,
I completely understand your frustration with running, wrecking and rebuilding ball diffs. At silverstone with plenty of grip you don't need a ball diff, you can be very competitive with a gear diff which will require much less maintenance. You mentioned that you were considering changing to a KF and I would say that is exactly the right thing to do for silverstone. You will go quicker and have an easier life without constant diff rebuilds. And you could probably pick up a used KF for not much more than the cost of a couple of new pro ball diffs. The SV2 is not a bad car, and I can help you to build and set your ball diff if you want to persevere, but the KF was designed for high grip surfaces, and you will have seen for yourself how many people run them successfully at silverstone.
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#9
22-07-2016
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Quote:
I like the SV2, it goes well, and was very cheap to buy new If only Schumacher had of made the KR diff compatible with the SV2, this post would not even exist! But unfortunately it is too wide for the gearbox housing even though the teeth diameter is the same from what I understand Tempted to buy a KF or KF2 but, it will require quite a big investment of time and money given everything. Also have some tough stuff at home currently which means I'll likely take the easier option of keep fixing the SV2 diff when its unhappy, due to lack of time to get stuck into a new car. Thank you
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#10
23-07-2016
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Your mistake seems to be when you are rebuilding the Diff doing the 90 degree bit, this only. Applied for new builds with new spring bevel washers once the washers are used they loose a little springiness.never leave it tight but don't slack it off as much to set it
__________________
MBModels - Schumacher Racing - Vapextech.co.uk - MRT - Savox - SMD
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Schumacher
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