Bosscat gone XLS

[19RC80KS]

Hi,

I've started a build project that is aiming to bring the Bosscat into the format of the legendary XLS. Basically, I love the original C.A.T. (as a jr I bought a kit from the first batch of SWB's that reached Sweden back in '86, I should have kept the car and the box...), and now I want a "future proof" XLS with as much Bosscat gear I can through into it.

Very much inspired by the fantastic works of Kaszal, Bormac, Jeroen, and others in this Schumacher forum, I had to get started.

The first problem I had to overcome was the missmatch between the width of the Bosscat chassi and the much narrower XLS body. I designed and cut a new chassi aiming at accomodating saddle-cells or LIPO saddles in a minimised polar inertia style (tight together). The upper chassi deck is a Bosscat hole pattern but with the contouring of the classic Corally chassi (just because it looks the part).

I wanted to get the transmission bullet proof so there will be a full works Bosscat drivetrain installed (unfortunately minus those unobtainable roller driveshafts). The inner alloy transmission housing, the upper shock bracket, the layshaft bearing housings and the sideplates are DIY-milled/turned by hand as I struggled to find these parts.

When I was racing back in the early 90's I had the excellent steel suspension balls and steel drive shaft crosses from Brittish SRM (they lasted for ever and made the plasic parts live longer too). Does anyone know if SRM still exists in some way or form? I miss the classic scene back then when there were a load of aftermarket tune up part suppliers for the Schumacher cars. What happened to Nodis, MMS, SRM, WASP, RCP, etc.?

Just like other great design classics, time has certainly proven and further manifested the greatness of the original C.A.T. design, I'm a fan of Cecil's designwork. Thinking back, it's amazing what a massive breakthrough this design really was. In my eyes a revolution that forced the rest to up their game substantially. Far from easy listening, a first hard core machine for those seeking a non-compromising racing system. As a bi-effect it also created a new product sign founded in minimalism and functionality. Very cool.

/ RM

[19RC80KS]

A few more pictures. The other kittens are my SWB and a Corally XLS as references + some period gear just because.

What kind of shocks would be suitable for this Bosscat XLS thing? Pro shocks would be an obvious choice, the Associated ones at the front will soon end up on a Dogfighter. Maybe some modern Schumacher shocks of today, the question is length of stroke. Would be nice to have silk smooth shocks.

Also, any tips on how to build the works transmission to the best possible standard would be appreciated. I've got ceramic balls for the diffs and the thrusts, 7mm HD belts at the rear, that wide orange belt of Kaszals pioneering seems like a must have. Are there any parts one can use from the Havoc etc. (I'm thinking drive shaft components, chassi parts etc.)? It'd be great to be able to define the ultimate formula for a Brushless optimised drivetrain in terms of parts and tricks/mods.

/ RM

[illshou]

Looking awesome. Where did you get the white spoke rims?

[isobarik]

Still avaliable at

http://www.jcracingproducts.co.uk/

nice build looking awsome ...

mvh isobarik

[Bormac]

Hi RM.
Great project you have undertaken. The Bosscat certainly makes for a very reliable runner/racer and will serve your purposes well.
Will be glad to watch as you make it evolve.
Cheers- Jason

[CAT3K]

Very cool build. Are you going to run the belt under the chassis like the XLS or over like the Bosscat? If it's under i'd be tempted to run a shorty lipo along the centre line of the chassis under the topdeck. It's something i've been thinking about with mine.

Paul.

[19RC80KS]

Still avaliable at

http://www.jcracingproducts.co.uk/

nice build looking awsome ...

mvh isobarik

Isobarik is right (tack!=thanks!), you can still buy them! I wish more of the (in this case mainly Brittish) RC tuning parts companies of the past would re-live to supply us with gems of the 80's-90's. Also, wouldn't it be nice if Schumacher could re-make some of the most hard-to find/consumable parts like (obviously) the alu roller drive shafts, the black CAT wheels and the equally difficult to come by; wide white sponge wheels (T671).

/ RM

[19RC80KS]

Very cool build. Are you going to run the belt under the chassis like the XLS or over like the Bosscat? If it's under i'd be tempted to run a shorty lipo along the centre line of the chassis under the topdeck. It's something i've been thinking about with mine.

Paul.

Hi Paul and thanks,

I will definetly run the belt over the chassi in order to make use of the full Bosscat drivetrain with the modern diffs both front and rear. For sure a shorty LIPO would have been a nice fit on a XLS chassi. I suppose I could still do that with a bit of a (ouch..) spacing to clear the belt on a Bosscat chassi.

/ RM

[19RC80KS]

Hi RM.
Great project you have undertaken. The Bosscat certainly makes for a very reliable runner/racer and will serve your purposes well.
Will be glad to watch as you make it evolve.
Cheers- Jason

Hi Jason and thank you.

I will try my best to make this a decent car, and will certainly post the progress here.

/ RM

[Groomi]

Some nice machining there. Looking good.

[isobarik]

aha det var du som köpte pk caten på tradera ...för länge sedan ....


mvh Isobarik

[kaszal]

RM your Bosscat is looking great!

I've experimented with a few different materials for the long belt. In the end I found a 6mm Kevlar reinforced Polyurethane belt, which is grey NOT orange. It has a higher modulus and you can feel it is less stretchy than the orange belt (polyester reinforced polyurethane)

I used 320T for my Procat but check your Bosscat, it might be different.

The SDPi part number is A 6B16M320060

https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=30647&GroupID=342

Hope that helps.

[19RC80KS]

aha det var du som köpte pk caten på tradera ...för länge sedan ....


mvh Isobarik

Yes, that's probably the same one. I had one full PK chassied XLS around '89-'90, with loads of custom parts. I sold it on eventually. The one you see in the picture here is missing the Ackerman bar, the upper wishbone crossmember at the rear, and the Shock stay is badly damaged, so it's only really the main chassi plates that remain PK.

/ RM

[19RC80KS]

RM your Bosscat is looking great!

I've experimented with a few different materials for the long belt. In the end I found a 6mm Kevlar reinforced Polyurethane belt, which is grey NOT orange. It has a higher modulus and you can feel it is less stretchy than the orange belt (polyester reinforced polyurethane)

I used 320T for my Procat but check your Bosscat, it might be different.

The SDPi part number is A 6B16M320060

https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=30647&GroupID=342

Hope that helps.

Hi Kaszal, thank you and thanks for the info!

I did some meassuring on the Bosscat Pro Diff pullies to see how much width there is available after fitting the 7mm rear belts. If I would keep the belt fences (and I should, shouldn't I?), there isn't much more space for anything wider than the 4mm standard width belt. I assume that the Procat Diff is providing more width for a wider long-belt or that the 7mm wide belts I use are creating the difference.

However, I can still use a modern Polyurethane belt of your recommendation from SDPi as long as it stays 4mm wide.

Another learning from comparing Bosscat anatomy with Procat anatomy; the long-belt length is seemingly different. I read 323 on my old Bosscat belt and you are using a 320 belt in your Procat. I take it they are not eaqually long then. That's good to know.

I had an idea after studying the exploded view of Schumacher Riot; it would seem like it has very similar but updated drive shafts/yokes. However, it also seems like they are beefed up and that makes me wonder if it would be possible to mix in some of these parts in our Retro Schumachers? The Riot wheel axle seems to be beefed to 10mm diameter, which rules out the use on Works Bosscat rear hubs which only have 8x12mm bearings. At the Diff side of things it would seem like the alu yoke could fit, at least it appears to have the length of cougar 2 Gear box yokes. What is really confusing is the cross interface at the end of the axles; is it larger diameter and if so; will it fit the old standard wheels?

A lot of questions here, but it would be great to have readily available, and uprated axle components for brushless use of old Cats. Have you tried anything like this on your Procat??

/ RM

[kaszal]

There's a photo of the belts on my Procat on my thread here...

http://www.oople.com/forums/showpost.php?p=625969&postcount=448

As you can see, I also run the Bosscat diff. The 5mm "high torque" Schumacher belts are fine for brushless if they're tensioned correctly. It's the long belt which is the weak point I think. If you swap out the 7mm belts you can use a 6mm long belt with no modifications.

SDPi do a 323T one in neoprene and a 324T in kevlar/polyurethane but I'm not sure if that would be too long.

btw the reason I only use 320T is because I use a smaller front overdrive pulley.

Watching your thread with interest, keep it up.