High speed G-maxx for ISC event, 100mph or bust - RC-Monster Forums

Rivermaxx · 09:51 PM

Some of you guys have seen my other thread on me wanting to compete in a ISC event with my G2 gorrilamaxx. After lots of research and help from various guys in this and the UE forum the project is on its way to become reality. My idea is to lengthen it for stability and keep it as low,narrow, lite, aerodynamic as possible, I am going to be using a mixture of stock plastic parts and some other exotic material parts and not normal parts to achieve this. Here are some pics and various stages of the build.

This is my Silverback build that I used the chassis from. I drove this truck quite few times and all I have to say is that chassis is awesome too bad they don't make it anymore.

This G4 is replacing the G2 chassis for a little different setup.More on that in the Silverback build in the near future. I like it a little better than the G2 because I am thinking it might be a little more stronger then the G-2 x brace setup. Not to mention parts are still available. So the G2 is getting sacraficed to the speed demon god.

One of the biggest issues with high speed is the foam donut filled tires will not handle high speed. There are a couple of options : HPI phaltlines on a tremor wheel or foam tires on a buggy wheels. The phaltlines are good for about 70mph if they are taped but after that they will most likely fail. The fix is to glue carbon fiber 20# test fishing line around the outside of the tire like this.

I really dont want to do this so I am going to try a different option.

The buggy foam tires on buggy wheels would work good for the speed but the problem is they are too small in diameter. My final gear ratio is to low and I will never get close to my goal. So the only thing I could do was get some custom made tires made. I found a company BSR racing tires who makes tires for on road cars willing to stretch some foams on wheels of my choice. The tires can only be maximum .300 thick though otherwise they will not last. So basically I have to find some big wheels. I originally was going to use the new 4" pro-line vtr wheels but that will only give me ~5" total tire diameter which is still a little short and my gear ratio will suffer. Eventually a guy on UE led me to some 23mm hex wheels made by CEN for their big 1/8 scale truck that are real big, ~5" to be exact. These will be ~5.5" with them trued & ready to go. Check it pics below:

Did I say they are BIG!!!!

I had to cut them down to 2 inches wide on a buddies lathe for better airflow and less weight and rotational mass. I could of gone thinner but traction might suffer.

These wheels are 23mm hex which is perfect because I have been reading the traxxas 17 mm hexes are sloppy and we all know 14mm wont last. My dace 23mm adaptors will work perfect for this build. I allready sent them to bsr and waiting to get them back. I am going to take a break now I hate typing. Next: I will have pics of some of the new special parts I have acquired because I took a little different route with this build. Feel free to comment and offer any ideas you might have as I could use any help I can get.

suicideneil · 09.11.2009, 09:48 PM

0.030" thick? Thats only.. umm... really thin.

I had an idea along those lines though, something like stretching and gluing a rubber tube over a modified rim, to get the same effect.

Ya know its interesting though, all these 90mph+ machines and not one of them has succesfully travelled back in time, or to the future either....

Rivermaxx · 09:58 PM

OPPS! I meant .300 thick . I even spell checked and I still screwed up. As far as traveling back in time and in the future. My build will do both you will know what I mean when I post up the rest of the build. Possibly might even surprise you neil on some of the out of the ordinary stuff I am doing.

_paralyzed_ · 09.11.2009, 11:21 PM

I plugged in the info on the speed calc. for my truck (http://rc-monster.com/forum/showthre...ight=cybermaxx) and had good numbers.

At 3.0v/cell on 6s with a 2200kv motor and 5.5" tires and a 25t pinion it came out to 108mph.

I'm willing to let you use my truck in a collaborative RCM effort to have the fastest MT.

I know your stuff is better, but your gear reduction screws you. I'd just borrow you the center diff, but you'd have to cut your chassis' to get it to fit. If you'd like either let me know.

If nothing else, good luck.

Rivermaxx · 09.12.2009, 06:11 AM

Thanks harold for the offer but I did a lot of research and searching for just the right parts and have got the gear ratio figured out. My stuff is not nescessarly better but maybe a little lighter youll be surprised when you see the pics. Biggest issue was the size of the tires killling my final ratio. That why I needed to not run buggy size tires. I also didnt want skeptics saying my truck is no longer a monster truck with the small tires. My actual final speed is alot higher with my set up than yours with a 2200kv motor. When putting in those numbers you need to use 3.00 volts per cell also. I picked up a real Neu 1515 1.5d 2700 kv motor which helps also. I am also running a 40 tooth spur and 30 tooth pinion. My truck now is ~7#s without electronics body and wheels and tires I am pushing for sub 9#'s complete. Most mt's are in the 11- 12 #s complete.

_paralyzed_ · 09.12.2009, 06:56 AM

I used 3.0v/cell.

I just want to see you accomplish your goal. jzemaxx 88mph run was done with a big and heavy truck, I see no reason why you can't beat that with a purpose built rig. Too bad his run wasn't "official"

I hope to see you on the pages of RCCA after november, and can't wait to see what you've come up with.

Best of luck!

Rivermaxx · 12:40 PM

What was that truck again? I think I seen the video on it but there was some descrepencys with it. They showed the radar gun and you couldnt tell what it said. I am not saying it wasnt done though, its just the video was not very good proof. Realize harold, even though I am doing what I can too make it work better it is not really a pupose built vehicle. MT's are not made to go even close to 100mph and most on road cars are not either. Its hard enough to make a aerodynamically sound car go that fast let alone a MT with the suspension and wheels sticking out. I must say OverrevO buddies 91.2 mph revo was one of my inspirations for doing this. One thing he says is they never got too that speed again only to 88mph. Maybe 88mph is the majic number just like back too the future LOL. My plans first are too break the current official record of like ~72mph held by a hpi wheely king on buggy tires.

suicideneil · 09.13.2009, 09:56 AM

I think it was an XTM Mammoth, or XTM something at anyrate- hefty 'gert MT it was...

MetalMan · 09.13.2009, 11:17 AM

XTM MMT

It is one huge truck!

Rivermaxx · 09.13.2009, 12:52 PM

I found it! http://www.youtube.com/watch?gl=JP&h...M&feature=user Theres a few thing that make me wonder. One of them is I didnt see them reset the gps, I couldnt tell what the gps said after the run. There was a guy holding a radar gun how come we didnt see that. I dont think those big tires wouldnt of held at those speeds either. Can a neu 1521 spin 95000 rpm with out breaking? It looks like it was going 60 mph too me. I am not saying it wasnt done but it just makes me wonder.

Rivermaxx · 09.13.2009, 01:43 PM

Here is some more pics:

Thats not the body I plan on running but it sure look nice too me.
See if you guys can recognize some of the different parts I am using. The aluminum wheel are what I used to do the alignment so they wont be used. I also still need to make a top plate out of 3mm carbon fiber. I was thinking of cutting the front skid to reduce a little more weight. and straightening out the rear for a wheely bar. So far it weighs 7.6 pounds with the aluminum wheels and batts, no front servo and electronics. I really think its going to be sub 9# when its done.
Some of the parts you probably wont notice or see are 7075 aluminum pillow balls all the way around, way lighter than steel. Titanium turnbuckles which I might switch to aluminum. The ue diffs have 6 spider gears, I have 8 spider but I figure the 6's will hold fine and are a little lighter. RPM big bearing axle carriers also.

I am going to cut this mount and re-clock it so the motor sits lower.

NEU 1515 1.5d 2700kv I picked up on the bay. I Hope it works

Add about 1.250" to the ride height.

_paralyzed_ · 09.13.2009, 01:47 PM

jzemaxx is legit. he posted here during the entire process. IIRC he's a turbo guru by day.

Rivermaxx · 10:56 AM

I build blown 572ci 1000+ hp engines on pump gas for fun, but that dont mean nothing. Here a vid of 2 1100 hp engines I built. It certainly doesnt qualify me anymore than anybody else.

I have been 140mph on gps in that boat and it will go faster ~160mph but not with me in it.
All I am saying is the video basically sucks and really doesn't prove he did it. Harold can you see the speed on the gps I know I cant. 95000rpm 1521 1.5d is awfully fast I thought 60000 was the limit.

suicideneil · 09.13.2009, 05:16 PM

This was the 78.6mph run, you can see the speed on the gps very clearly. I can just about make out the 80.4mph too, but its on its side, so you really have to squint..

Rivermaxx · 05:41 PM

Yes, that thing hauls a$$ but they still didnt reset it in front of the camara. I can save 100mph in my gps for fastest top speed in my 1:1 car. Would you believe it if I pulled the body off and it showed 100mph on video. All I am saying its very easy too fool people. If you going to do it, reset the gps on video so there are no skeptics. Besides that record was beaten by OverrevO's 91.2 mph run on only 6s not 12s with alot smaller 1515 motor. Its basically an 1/8 scale also.