Uh...Ya got me...If I were you, I would personally choose a Neu 1515, but for me, a Basic XXL would probably be the choice depending on price. I can't really spend $75 more on a motor that won't perform much better than the one thats cheaper. I originally bought a XL3100 and regret that to no end...I fried it..$150 bucks down the drain...If I had just gotten an XL I would probably still have it and would have came out $60 better...(rant over). Besides, I would probably have to use a cheaper ESC like one of the Warriors I have, so a Neu would be out of the picture and a LMT is just plain to expensive.

I really like the 1512 I have in my buggy. I'm sure a 1515 would run great but I don't know if you need it or if it's a good thing, esp if you want a lighter setup.

My car runs 8.0lbs fully rtr with the 4s 6000 packs. I've run it geared from rather slow 15:1 (10/46) all the way to 50mph-range 8.4:1 (18/46) in the street. On the track I've been running about 11:1 (14/46) which hits 30mph or so. My motor is the 1900kv. I think you can go up just a little in kv and still have a good range of gearing options. I would grab the 2000kv one if I did it over again. The 2600 is too high for me... for racing anyway.

Lower kv means lower currents... at the same voltage, and should be more efficient than the hotter winds. I don't know what happens when you gear the different winds for the same speed... that's the $64,000 question and I assume that's what you mean about the runtime going down.

I got rained out again from doing some playing around (errr... I mean testing ;) ) tonight... but I've been meaning to experiment with gearing some more. And get some video. Maybe tomorrow.

The 1512 motor is pretty nice. The 2.5d is 2000kv. I get about 45 mins on 6000 mah maxxamps lipo. The 1930 10t may be an option for you as well. It has good power to.

In another Hyper8 thread, I was asking about possibly using a plastic/Delrin spur and was informed that the Kyosho 46T plastic spur will fit (with possibly a little shimming). Well, I was looking at the assembly diagrams and noticed that the steel spur has a little "collar" on it that supports the diff bearing. The plastic spur does not have this, so how will this work? Do I just get a different bearing that has the same OD, but smaller ID so it fits snugly directly on the output yoke shaft?

I've attached an excerpt from the manual with an arrow pointing to what I'm talking about.

The Kyosho plastic spur does have the collar for the bearing....

Yep, no problems there.

If shimming was needed were would you shim it at?

Thanks GD and MM.

Cartwheels: If there is a difference in thickness of the gear, the mesh inside the diff cup may need shims to set it right. As to "how", I'd imagine you just add them on the shaft wherever needed...

Yeah, like Brian said. The way I do it (not saying it's the right way) is to put a buch of shims in the diff so it binds, and then remove shims until the binding is gone.

I'm trying to figure out where/how I am going to fit two packs of 2s 8Ah Lipos on the chassis without any part of the battery touching/laying on the dirt guards, while not hitting the center diff or servo.

So, I thought I'd get/make a spacer bar that would make the battery trays sit high enough to clear the dirt guard "nibs". I figure a bar that's 9mm high X ~100mm long X 20mm wide should provide enough support for the battery tray. Now I'm looking for the right material to use for the bar. If metal, I'd have to tap some threads (umm, rather not). If plastic (preferred), I'd have to pick a type that will hold threads, so it would have to be on the soft side. What type of plastic should I use? At http://www.mcmaster.com, I have ABS, Garolite, and Nylon to choose from for the size I need.

Below is a rough picture of the spacer idea, which is shown from the rear end looking forwards. Basically, you are looking at the end of the lipo pack.

I would go for ABS.

Is ABS the type of plastic used by Traxxas and other brands? Those types of plastics hold threads pretty well. Or, whatever RPM uses for their plastics...

If I can't find a plastic that I think will work well, I may just use aluminum. Like I said, I'd have to tap threads though and I've never done that. I heard 7075 is difficult to tap, but what about 6061? Any recommended tapping tools, or will any suffice?

Either way, I'll probably use standard 3mm countersunk screws.

This project is gonna be costly. It doesn't have to be I guess, but I'd like it to look like it was designed to be a BL truck from the maker. One thing I have to do is talk to Mike about making a combo motor/center diff mount to replace the stock diff mount. The battery trays will be ~1/16" aluminum plate that I want to have cut and bent to order. I may also incorporate slots in the batt trays so I can adjust the total length to suit the exact lipo packs I end up getting. I'll probably get a 1515 Neu motor - after careful measuring, I think it will fir. By the time the rest of the buggy is done, maybe Castle will have released their Monster Max ESC. The more I think about this, the more I can hear my credit card whining!

Brain, 6061 aluminum would be a good choice. It shouldn't be to bad to drill and tap. Sears should have a good set of taps you can get . RPM uses a type of nylon I believe. Pretty sure its not ABS.

Cool. I might stop by Sears tomorrow to see what they have. I've checked Lowe's and the like and I can't seem to find a decent set for smaller scale stuff. My LHS had part of a set - had the actual tap but no handle. :rolleyes:

Something for you to think about, you could go with a rectangular tube instead of a solid block to reduce weight. Something like this might work:
http://www.industrialmetalsales.com/1972.html
It's 12.75mm tall instead of 9mm, and 25.4mm wide instead of 20mm. I think 6063 is just a more corrosion-resistant version of 6061, and it should definitely be strong enough (the walls are 1/8" [3.17mm] thick).