12 replies to this topic

[merther]

I have SD drop gears fitted to my car, they are the minispares ones. They seem to be a lot louder than any others I have heard. From the outside of the car you can hear it from a long distance away and it's very high pitched. Others I have heard aren't so loud.
I have adjusted the ratio using different number of teeth on the primary and input.
Does the noise vary depending on the ratio / teeth on the gears does anyone know?

[nicklouse]

The noise has more to do with the tooth profile and the fit between them. Mainly between the primary and idler.

 

the different ratios is more to do with adjusting your final drive ratio to suit the event.

[imack]

I've got minispares sc drops, originally bought as 1:1 ratio (23 tooth) setup. Have swapped primary for 22 tooth, definitely louder now.
Would be interesting to know if 24 tooth 1:1 setup is quieter than a 23 tooth 1:1 setup.

[Spider]

Misalignment between the Transfer Housing and Gearcase will also have an effect on how noisy they are.

 

All that I have closely looked at for this over the past couple of years have had misalignment, some worse than others.

[mini13]

I think the non 1-1 ratios may compromise the mesh slightly to get the ratio change, your loosing a tooth on somthing but still keeping the same distance beween the shafts. Also youve not done anything like line boring the block have you? or changing the Block-Gearbox gasket type ( thickness)

[Rorf]

I fail to see the point of installing noisy SC transfer gears on road cars.

[luismx123]

I fail to see the point of installing noisy SC transfer gears on road cars.

i heard less power lost?? not sure about this...and SC, cus cool 

[merther]

Thanks all.

I fail to see the point of installing noisy SC transfer gears on road cars.

It's not a road car :)

[MiniMadRacer]

Assuming a race car straight cuts cut side thrust, and therefore give you out and out power with minimum "friction waste"... on a road car, pretty pointless, but does reduce side thrust wear if you shim them properly in the first place, but the cost of straight cuts usually outweighs that benefit.. helical gears generally "push" away" from each other causing "side" forces.... straight cuts "properly" shimmed stop that waste prob saving 2 /3  HP... which matters on a race car.. where cost is pretty much secondary / irrelevant to gaining a few tenths here and there

[Spider]

 but does reduce side thrust wear

 

Here's how I got around that 

 

 

[Rorf]

Moke, never mind your exceptional engineering skills, all those parts are immaculately clean - I love it

 

Looks like someone did the screw driver trick on that gearbox/transfer case interface

[mini13]

Nice! there was talk of minispares introducing a helical Timkin set of drops a while back, I gues it got shelfed, would go really well with their new helical gear kit though

[Dusky]

Assuming a race car straight cuts cut side thrust, and therefore give you out and out power with minimum "friction waste"... on a road car, pretty pointless, but does reduce side thrust wear if you shim them properly in the first place, but the cost of straight cuts usually outweighs that benefit.. helical gears generally "push" away" from each other causing "side" forces.... straight cuts "properly" shimmed stop that waste prob saving 2 /3 HP... which matters on a race car.. where cost is pretty much secondary / irrelevant to gaining a few tenths here and there

More like 0.2 hp