Losi XX4

[Basher67]

I'm strangely drawn toward this XX4 I picked up. I've decided to build it as a runner and see how these old 4x4's hold up. The design and engineering of these cars is really cool and there seems to be no end to the praise these things receive from bitd, so I've decided to see for myself what these cars are all about. I'm definitely an AE guy and not a Losi guy, but I'm going to give my honest opinion, for what it's worth, on build design, ease of maintenance and tuning, and so on. For power, I have a Novak Hammer Pro esc and an assortment of modified brushed motors as well as a couple brushless setups to try. I was lucky enough to find a buddy of mine selling this Venom 4600 mah lipo saddle pack at our local swap meet and picked it up for $20 still new and sealed. I'm going to set this up for my local track which is indoor offroad turf.

The car I'm starting with that I picked up in a recent collection is a little rough. It appeared to be fairly clean, but as I tear into it, I've found some things in need of replacement. The belts were completely disintegrated, One of the pulleys is shot and another is worn enough to make me frown about it. All of the bearings need a thorough cleaning and possible replacement depending on how the cleaning goes. On the upside, the car seems to be complete and I couldn't find anything broken. I ordered a new belt set from tough racing, a new body from TBG and a new set of pulleys. As soon as the pulleys arrive I'll get started. The car came with 2 front yellow wheels and 2 white rears. I was going to dye them all black, but a track buddy of mine has been looking for a set of rear whites, so I'm trading him for a set of yellows.

Also as a side note, for those of you wondering about the cheaper brushless esc's, I will be testing one in this car. I have a few different brushless esc's these days, but I wanted to see how cheap I could go. I ordered the cheapest sensored brushless esc I could find on ebay. It was $16.79 and free shipping. It claims to have 120a continuous and 760a burst rating and uses a Hobbywing program card. My first reaction at these numbers is "cough cough" bull$#@t but I have some nice sensored motors ranging from 17.5-8.5t so we'll see what it will do. I prefer hobbywing esc's and already have their progammer so that was a plus.

[matt1ptkn]

XX4s are fantastic, there's no question about that. On our indoor, off road, carpet track, however, I'm unable to tune it to keep up with the modern 4WDs. (But that may be mostly due to my driving skills.) Maintenance on these can be a pain. Get the belts right the first time so that you don't have to tear the entire car apart for belt maintenance. The long center/rear belt cover can be cut into two parts, which will provide easier belt maintenance, but doing so can add another location for potential dirt infiltration. I'll be looking forward to your progress and thoughts!

[NomadRacer]

Interested to see your testing with the "cheap" ESC.

[Basher67]

Interested to see your testing with the "cheap" ESC.

Me too. I have been using the hobbywing justock in my B6 for a few months now. It gets 4-5 packs run through it 1-2 times a week. It has been flawless. I'm curious to see how similar the cheap esc's are physically, performance wise, and durability wise. After using quite a few brushless setups over the past year that range from high end race equipment, to cheap chinese ebay stuff, I'm coming around to the belief that in many instances we're being duped into paying more for a "big name" sticker. I'm going to post the results of the tests in the Modern Electronics area when I get that far.

[Basher67]

The esc showed up in the mail today. They didn't waste any money in packaging, instructions or anything else Not sure about the TSKY "enjoy myself" sticker on the fan. I think something was lost in the translation. It does come with a dual capacitor already soldered in, which was nice, but the tall on/off switch feels cheap and easily broken. I know many racers who eliminate the switch from their esc's so this crappy looking switch is not necessarily a deal breaker. Still waiting on the pulleys to start reassembling the car.

[Basher67]

The new pulleys arrived today so I finally was able to reassemble the car. I really like the design and construction of this car. I can see why it was such a big deal in its day. The design and engineering that went into the layout and construction is impressive. I couldn't find anything during the build that looked like an afterthought or compromise. I don't think there is anything better than a shaft drive for a 4WD RC, but this is the best belt drive car I think I've ever seen. Have I finally found a Losi that I love?! Ok. let's not get carried away, but it is a really cool car. The original wing isn't perfect but it's got that vintage flavor----I just couldn't throw it out. A little modification to the hold down straps and the lipo saddle packs are a perfect fit. After a little trading with a buddy, I was able to come up with a complete set of wheels in really nice condition, but I don't want to destroy them on the track. I have some wheel adapters that let me use the rear dish wheels off my B6 with perfect backspacing and I just ordered a set of front dished wheels from Sabula Tech. Tomorrow is race day so I'm done for tonight. I'll post any new progress tomorrow if I get anything more done.

[Basher67]

Just waiting on the body and dish wheels now before it goes to the track. I decided to skip any testing with the brushed motors and start it out with the $17 esc and a Reedy M3 17.5T motor. It will probably end with a proper esc and motor for it's age, but for testing, I thought I would jump right into the brushless cheapo esc and see what breaks first.

[Basher67]

Body came in the mail today. I threw some paint at it, sort of "box artish" style. I don't have any Losi decals, but I plan on running it hard at the track so it's good enough as is. As soon as the front dish wheels arrive, we're off to the track for some test runs. One thing I noticed while fitting the body is that there is no extra room at all inside. It could not fit any tighter. I will be taping up some of the inside of the body to help prevent premature wear of the paint from the inside. It is definitely a good looking buggy. The body came with a new wing, but the old one has plenty of life left in it and I like the old school decals.

[Basher67]

Here she is, track ready. Ran a few laps yesterday before the race with it. Once I got some expo dialed into my steering and took a couple laps to get used to the car, it actually ran quite well for a 20 year old 4x4. It needs to be lowered in the rear and while the 17.5 reedy motor was adequate to clear all the jumps, I think a 13.5 motor with the right gearing would really be the ticket to make this a real rocket on a modern turf track. The weak link appears to be the steering link that looks like a servo arm that is mounted to the steering rack. Plastic parts with no servo saver on a high grip track is a recipe that guarantees broken parts. The design is sound, but an upgrade is needed here. Aluminum bellcranks and servo horn linkage would be the ticket, but I don't know what's available.

[Basher67]

Well, it's decision time for the XX4. Keep it or sell it time. I have to say, I really like design and engineering that went behind this car. Nothing seems like an afterthought. I didn't see any obvious weak links while building it. Appearance wise, it's a sexy buggy. Definitely a head turner that got plenty of attention at the track. As far as keeping it for a track runner--- there are a couple issues. I run on an offroad turf track which is very hard on the cars. The steering components are not designed to take the kind of beating that is regularly seen on these tracks. The answer would be to upgrade the components to aluminum or titanium, but no parts are easy to find for these, let alone aluminum upgrades like the rare high-dollar trinity pieces. The other big obstacle is the rear ball diff. Ball diffs can be marginally effective on turf, but a gear diff is really a better way to go. On dirt, I can see this buggy still being competitive on the club level, but turf really needs a gear diff and parts availability if you want to race it. It doesn't really fit in my collection and racing it might turn into a neverending parts search, so this one is going up for sale I'm afraid. On a good note, the el cheapo 2.1 esc clone is still working flawlessly and will be transplanted into another truck soon. You can follow along as I continue to flog this esc over in the modern electrics section.