simplechamp's Jammin X2 carbon on-road GT
 

Finally putting to use the Moos Racing CF chassis I've had for awhile now. Been collecting pieces for awhile now and finally starting to put it all together

Tonight I built up the diffs, alloy cups all around and hardened steel internals. 50k front, 100k center, 30k rear. For the center I have the Slipperential and built up a standard center diff also.

Rebuilt the shocks. There will be Hyper 9 17mm front big bores and all 4 corners, internally limited, 60W oil and firm springs. Stock pistons to start out. Using X2 CF front tower, and modified X2 CF rear tower. Trying to lay the shocks down quite a bit.

Bought a new steering rack on Ebay and put it together with a Kingheadz ackerman plate. Trying to put some red accents with the concave washers and red bearing seals (don't see much of those though).

Only pics I took so far are kind of a mockup of the layout, still need to make an ESC rack to mount on the back of the center diff. Also still waiting on NEXX8 lipo trays and Kyosho IGT body mounts and front bumper.

More to come soon! (Mods if you think this should go in the buggy section feel free!)

http://i47.photobucket.com/albums/f1...3/P1030180.jpg

http://i47.photobucket.com/albums/f1...3/P1030181.jpg

On road is good, that thing already looks too good to drive in the dirt!!!

You didn't mention a specific body, any plans there?

looks awesome :D

got a target speed in mind? or is it a racer rather than a drag car?

I have been looking at MANY bodies. IGT Hobbies just started bringing in those Deltaplastik bodies from Italy, so I think I'm going to pick out one of those, I like the Mercedes. Otherwise IGT1 bodies are the correct wheelbase, and I like the Subaru or Calsonic Nissan.

Speed will probably be 40mph like I usually start out at. This is just a parking lot basher, no tracks near me unfortunately, and not really looking to set any speed records. I'm a little suspect of the Vector 8 motor, it's more of an experiment until I can afford a Tekin. Once I get a Tekin I'll probably ramp up to 45-50mph.

If I have time I'm going to modify the rear tower this evening. Grinding it down so its similar profile to the front tower, and drill new shock mounting positions.

You can still get a few motors on the castle site for a song and a dance, cant realy go wrong there, unless you're looking for a sensored motor?

Not familiar with the Deltaplastik bodies I'll have to check them out.

I thought about a 1512 2650kv or 1800kv but I really do want to try sensored, it will be my first chance to play around with the dynamic timing advance. The only other motor I might consider that isn't sensored is the Castle 1415 2400kv that they are releasing with the new MMP short course combos.

The Deltaplastik bodies look really great, they have a ton of selections to choose from. They are still a bit pricey at $90, and I might end up buying a pre-painted, pre-finished IGT1 body for the same price.

http://www.igthobbies.com/category_s/41.htm

Here's the diffs. Innovative RC alloy cups, HotBodies hardened steel internals, Ofna hard-coated alloy bevel shafts, and Sportwerks TiNi ring gears.

The Slipperential needs a rebuild and I might rebuild it with one of the Delrin spurs. As of right now the regular center diff is going in.

Second pic is the shock towers. Stock X2 CF front is on the left, and the modified X2 CF rear is on the right. The rear is now about the same profile as the front with same shock mounting positions.

http://i47.photobucket.com/albums/f1...3/P1030185.jpg

http://i47.photobucket.com/albums/f1...3/P1030187.jpg

Nice work, I like it alot!

Thanks! I am a carbon-fiber junky, so this is like my dream come true!

I got the NEXX8 lipo trays today, and they look like they'll fit great. I just need to get the rear end assembled so I can mock it up and position the trays properly. Looks like there should be plenty of clearance.

Nice Work Indeed.
 

These are great pictures simplechamp.

Thank you for posting your latest project up. Looks outstanding. Keep up the great work :)

PS. I'm looking forward to following this project as it progresses. Please continue to post many detailed pictures of your carbon fiber 1/8th scale buggy- as you continue to build your system :)

Wow Wow Wow. Nice work SimpleDude. Looks like the motor will survive with that setup. Keep the startup low(peak amp down) and all should be good.

Got everything built for the most part. Just need to drill and countersink the mounting holes for the NEXX8 lipo trays, and wait for the bumper and body mounts to show up.

Unfortunately it's going to be awhile before I can drive it because I live in the Arctic circle, but that's plenty of time to save some cash and pick out a nice body.

http://i47.photobucket.com/albums/f1...3/P1030189.jpg

http://i47.photobucket.com/albums/f1...3/P1030188.jpg

I'm jealous mang. Really liking your bling build.

Thanks!

I consider this my first "real" build. All my other vehicles have been rollers, or already converted, etc. This is the first one where I started with a pile of parts and picked out everything I wanted. Using lots of brand new parts and taking the time to shim up EVERYTHING properly was really an eye-opener to me. Never realized just how much slop and wear there was in my buggy until I rebuilt it and saw how it's supposed to feel!

What do you guys think will look better, the red accent washers, or I also have gold? I really like the gold, but my plan is to get a Tekin motor (maybe RX8 too?) eventually, so the red will match better.

EDIT: One more thing I've been considering. I plan to definitely use a DE Racing rear skid, and maybe one in the front (unless the IGT bumper mount comes back far enough). What about putting like 2 thin rails of plastic/Delrin running along the bottom length of the chassis to help protect from road rash? I'm not too worried about the ground clearance or having to raise the ride height a few mm. I thought about that chassis protector film also, but not sure about it.

A plastic rub strip on the chassis is a good idea. I thought about doing that myself, as the parking lots I bash in are a bit uneven, and not really very clean.

Any idea of what I should use? Or source for some thin strips of Delrin?

Or maybe just use some thin strips of aluminum? Those are easy to find at any hardware store, but I feel like the plastic/Delrin would be "slicker" and less likely to catch on something. I'd bevel the edges like the DE Racing skids.

I have been following your on-road build too, looking good!

Are those gold coloured bevel gears on your front/rear diffs lightweight solid titanium alloy units or just titanium nitride coated steel for ware resistance like drill bits? I may have to investigate whether they will fit my hot bodies diffs or if anyone else makes ones that do if they are solid titanium and offer a decent weight saving.

Thats a good idea with the rub strips, my buggy is much stiffer since my on-road conversion so even with the reduced ride hight im not planning on grounding out much, but like yours my surface isn't the best (thats why we convert buggies rather than just run serpents right) and I'm sure it will get the occasional scratch, I'm now thinking of gluing 2mm titanium welding rods that can be found fairly cheaply on Ebay to the underside, one down the middle and one down each side which should give good protection to the bottom for very little weight gain and also give a cool firework show like the F1 cars do if it grounds out.

I'm digging all the carbon, you should consider making carbon battery trays too, very lightweight and lower CoG too as they sit directly on the chassis.
http://i22.photobucket.com/albums/b3...ethydro010.jpg

The diff gears are just TiNi coated, the material is steel as far as I know. The were made by Sportwerks, which discontinued it's RC vehicles and parts, but Losi has the same exact gears too. Part # LOSB3535. They should fit your HotBodies diffs fine, the alloy diff cups I'm using are actually Lightning Stadium cups, they are the same as Jammin cups.

I think I'm going to stick with the NEXX8 battery trays for now. They might be a little higher COG with standing the lipos on edge, but they fit perfectly with the chassis layout. I might try a single pack setup eventually, wouldn't be difficult to switch at all.

P.S. I've always really liked your CF rallygame car, it's one of the things that inspired me to do mine!

Thanks, blew up my esc in the testing phase so I will have to rob one off another vehicle.

Maybe abs plastic would work? That is pretty cheap and available everywhere.

Ordered a piece of Delrin and a piece of PTFE (Teflon) on Ebay.

Anyone know if you can dye PTFE? The Delrin is already black, but the PTFE only came in white.

Hey, I just ordered RCM mod 1 28T and 30T pinions for the GTP's. Had to mention it for those days you feel like doing a speed run with your carbon chassis.

I didn't realize RCM had pinions that large now. Good to know. Size DOES matter :wink:

I am currently running a 24t in my GTP with my Castle 2200 combo. On 6s I should be able to hit 100. on 4 and 5s it is somewhat controllable but all the way fun.

You are going to need to look into some foams or some more tires. You are sure to rip the rubber right off the wheels with minimal throttle application.

I've always really liked your rides Big House. You and nativepaul are really where I got the ideas to do my own CF on-road project.

Received the Kyosho IGT bumper and body mounts today. Both fit great. Just a matter of drilling a few holes in the CF shock towers for the body mounts, and I'll do that when I'm drilling the holes in the chassis for the battery trays.

The bumper holes lined right up in front, so no mods needed there. It doesn't come quite as far back as I had hoped, but it should work. I may look at adding a small piece of the Delrin behind it.

Those are the last few things needed, along with making some rub strips and getting a body. It's really all finally coming together!

Sent out a stock alloy ackerman plate to Damon @ Diggity Designs to have him make a few for me out of CF. I thought about having him do the FF and RF hingepin holders, but I think I'm going to keep them alloy for now. Besides those I think I'll have just about as much CF on this baby as I can!

I think that was a good choice, I did make a set of CF hinge-pin carriers but carbon has wears poorly and I decided that I would have to glue the hinge-pins to the carriers to make sure the arms turn on the pins and get good life out of them before slop developed, but as arms and pins are the only thing I have had to replace on my buggy so far I thought that making a new set of carriers each time I change an arm or pin was a bit much for the weight I would save, especially as the big 5mm thick front and rear ones which I assumed weighed a ton turned out to be mainly hollow with thin stiffening webs.

Yeah, that's what I figured, probably wouldn't work out the best. You could maybe improve the design by using plastic inserts like some newer vehicles use, but the alloy are fine as they are.

I think it's needless to say I have more than enough CF as it stands now! I know there are a lot of people out there who wouldn't put a single piece of CF on their RC's, and I understand some of the arguments against it. But for me I just love the stuff, not only for it's properties, but also because I love the look. In the end it's my RC so I'll make it how I like!

Received a 50T Delrin Slipperential spur today and rebuilt my Slipperential with it. Needed to go with the 50T because I'm using the high kv Vector 8 motor, and my gearing options were too limited with the 46T. Going to start out with 15/50, right about 42mph. This will be my first time using a plastic spur, so I look forward to trying it.

The spur was a bit too large to clear the chassis so I added in some black nylon spacers to a big order I was placing at Bolt Depot already.

I also decided to can the idea of using 1/8 buggy front shocks, and I'm now going to be using Revo shocks all around. Main reason being the cost and availability of proper rate springs. I was looking at both Jato and Revo springs, and it looks like the Jato springs should be good for what I need. Probably pick up the variable damping kit to play around with too. I used to have all this stuff when I had my E-Revo. Sucks when you sell stuff and then end up having to buy it again!

I was originally planning to run DM-1 shock towers in my Jammin conversion since they both use the same bulkhead, but then decided to use modified X2 towers. After kicking that around for awhile and also changing my shock choice (from 1/8 buggy fronts to Revo shocks) I finally found the perfect towers, which are from the IGT.

The IGT towers bolt right up to the Jammin bulkheads, since they are almost identical. There are only two small mods that had to be done. One was adding a tiny amount of clearance on both the front and rear towers, and was about 30 seconds of filing, VERY tiny amount of material removed (see pic 1, highlighted in yellow)

The second change was that the hingepin holes in the IGT front tower didn't line up quite right with the Jammin upper hingepin holder. I just decided to get rid of the front upper arms and hingepins altogether, and use a turnbuckle setup instead. Already had the parts in my spares bin. (see pic 2)

So now the towers are all set, and seem just about perfect for the Revo shocks with all mounting holes usable for plenty of adjustment. And the body mounts can be placed on the stock IGT tower locations rather than me guessing with the modded X2 towers, so I know the bodies will go on right. I'm going to run the plastic towers for now, but I'll definitely be saving up for a set of CF IGT towers.

http://i47.photobucket.com/albums/f1...3/P1030200.jpg

http://i47.photobucket.com/albums/f1...3/P1030199.jpg

I like how you built up those diffs with a bunch of different brand parts, sounds like they are bomb proof. Any issues at all with fitment, anything not lining up/clearance issues and needing machining?

Awesome build though man, I'm not really a fan of onroad cars but this is top shelf, great work. I missed it somewhere in this thread, but what chassis are you using?

I am using a Moos Racing chassis, there is a thread about them in the "Product Reviews" section: http://www.rc-monster.com/forum/showthread.php?t=27360

The diffs all came together perfectly believe it or not, I call them Frankenstein diffs LOL! The only part I was unsure of was the Sportwerks TiNi ring gears, but they bolted up just fine. I had to shim them a bit inside the diff bulks, but you'd need to do that even with the stock diffs.

I am waiting on some CF ackerman plates to show up, and now also need to save up for CF IGT towers. Another thing is finding the right spring rate for the Revo shocks. For Jato and Revo springs there is anywhere between like 5 lb/in all the way to 30 lb/in. I emailed Nitrohouse to see if they know what the Ultra GTP and DM-1 use, just to give me an idea of where to start. Still waiting to hear back.

I don't mind it going a bit slow, I want to take my time and do everything perfectly to how I want it. No compromises! Plus I still have quite awhile left until the snow melts and I can actually drive it.

Very nice build, definitely interesting with a the mix of parts. FYI the manuals and parts listing for the GTP and DM-1 are availible on nitrohouse. E-GTP2 uses 1.8 springs all around, DM-1 didn't have a litsting for just the springs, but I might have missed it.

I did notice the GTP2e springs. The problem is that they are giving the spring in wire diameter and # of coils, and I need to find lb/in or N/mm. The good news is I found a few charts listing 1/8 on-road spring rates, and also a formula to convert wire diameter and # of turns (plus a few other values) into lb/in. So I should be good to go on the springs, at least a good starting point.

I have just about enough cash saved up for a body. Would love to hear opinions from you guys. I know in the end it comes down to what I like best, but always like to hear suggestions.

Here are the bodies I am choosing from: http://www.igthobbies.com/category_s/41.htm

EDIT: For anyone else looking for a good starting point for 1/8 on-road spring rate, here is the chart someone gave me. Seems like 20-60 lb/in is the average range.

I knew about the turns, didn't know they were giving the diameter instead of the rate though. Good to know. I like the 80's 911 body alot, it's different and looks proportional too.

It's nice that Bill from IGT Hobbies started bringing in the Deltaplastik bodies. They aren't cheap, but shipping is free. And you would pay the same or more ordering from Italy with the ridiculous shipping cost, and then you have to worry about it getting lost, delayed, etc. Bill said right now he gets the bodies on an order-by-order basis, and it's about 2 week wait. He said once he gets an idea of demand, popularity, etc. he might start having some in stock.

Got my CF ackerman plates in yesterday and mounted one up. Along with them I got a few small pieces of 3mm CF just to have on hand for any custom parts I might want to make. Mainly I am going to make a center diff top plate that extends out as a rack to mount the ESC.

Should have some more pics soon of the whole thing actually assembled.

http://i47.photobucket.com/albums/f1...3/P1030218.jpg

http://i47.photobucket.com/albums/f1...3/P1030219.jpg

Would you mind posting the formula and where you got it? I'd like to add it to the calc pages, but want to give proper credit for the original location, if applicable.

Good idea Brian, I would really like if it was available on your site. It was posted on RC Tech a few different places, not exactly sure the original poster, or where they got it from. I added a few changes/notes also.

The formula for calculating the spring rate of a compression spring is the following:

K = (G*d^4)/(8*D^3*n) (remember your order of operations guys! :wink:)

where:

K = Constant (spring rate), pounds per inch of deflection, (lb/in)

G = Modulus of rigidity (shear modulus, approx. 11 million psi for steel)

d = wire diameter (in inches)

D = mean coil diameter: outer diameter of spring minus wire diameter (in inches)

n = number of active coils (the very last top and bottom parts where the spring is closed and ground are not considered as active coils)

Here is a calc at Engineer's Edge: http://www.engineersedge.com/calcula...ring_k_pop.htm

I tested out the formula and calc using a Revo spring of known rate, and it came out just about perfect using 11 million psi for modulus of rigidity. You can convert lb/in to N/mm (common metric unit for spring rate, used by Traxxas for Revo/Jato springs) by dividing by 5.7, and then of course N/mm to lb/in by multiplying by 5.7. Studying the formula you can see how a "progressive rate" springs are made, by either changing the spacing between coils at various parts of the spring, or the mean spring diameter at various points. It could also be accomplished by having a wire diameter that varied in thickness, but that's not very practical compared to the former 2 methods.

Believe me, in the search for the right springs for my 1/8 on-road conversion I learned more about springs than I ever thought I'd want to know!

When I still planned on using the 1/8 buggy fronts (Hyper 17mm Big Bores) I learned I would need to order springs from a spring manufacturer, since none of the available stock springs were firm enough. I found quite a few options, but they ranged anywhere from $10-30 a piece (most places required an order of 100+ to get anywhere near a reasonable price per spring.) That was one of the main deciding factors that made me switch to Revo shocks, which I'm glad of now as they seem perfect for the job.