XTM MMT speed runs today on GPS and camera.....
 

Well guys took the truck out today with the Turnigy HV controller this time instead of the HV110. One thing I was concerned about is the truck appears to have dropped 2-4mph from the HV110, BUT the HV110 was never ran in the heat. My high speed runs were done with it in temps below 55 deg. Today the runs were done in 77-80deg weather. Any reason why this would happen, is the HV110 more efficient from input to output??? Anyhow, on 8s...

8S with 17/70 gearing and HPI Phatlines - 70.2mph, backed it up with a 69.9mph run and 69.2mph.

10S with same gearing on same tires - 76.0mph, backed by 75.9 and 74.8mph as well as a host of other runs.

I tried the truck with no body on it and it ran 76.0mph as well, but handling sucked since I have no down force.

Truck weighs 17lbs with this setup.......maybe worlds fastest MT for right now??

http://forcedinductions.com/images/f...pics%20002.jpg

http://forcedinductions.com/images/f...pics%20001.jpg


Video will be downloaded tomm and on youtube...I will link it here. BTW, the truck is only running the 1521....hehe

I just looked it up, Dave Cornell won the fastest MT challenge this past event with a 72.9mph and second place was John Crook ran 70.7mph with an emaxx. So this truck is alot heavier,still has 4wd and runs a true truck body. So I really am loving this MMT truck.... Anybody want to buy some emaxx's...lol

:lol:"only running the 1521":lol:

That is one fast truck.

I want to see video of this. Nice work.

I forgot to post for the guys asking. The temps were hovering at 125 on the ESC and 120 on the motor. Going to try my 18T, 19T and 20T pinions and see what happens. Goal is to break 80mph with this big heavy truck.

Congrats man. What winding is the Neu 1521(Edit: found it, it's the 1.5D)? Now I got to start getting my stuff ready to beat that :lol:.

I hear ya man... I'm working on some stuff now too.. but I don't have any Neu's or Lehners on hand.... :neutral:

Jze... seems like you have perfect gearing right now, judging by ur temps.. I wouldn't change a thing man.. what Lipos are you using?..

Using TrueRc's for the 10S runs and Zippy's for the 8S runs. I think I will try just a touch more gear. I am shooting for 80mph.

ITs the 1.5D......best motor so far I have ran. It did 74+mph on my Emaxx on 8S as well. So its a proven performer time and time again on my setups.

aqwut,

My daughter's uncle lives in Canada and I'm going to ask him to take some spy shots of what you got cooking over there :lol:.

you so are running about 3000 Watts?...

LOL, Lutach... Nothing Special... :mdr:

Hey don't count out my big 1/7th scale XTM XLB buggy. Same size as the MMT, but I'm working on the 100mph setup on it ;)

Im calculating around 3700 watts or more. 37V nominal under load and no less then 100amps from that motor with that kind of weight and speed.

100 MPH is going to be quite hard... the power will be there, but you'd have to modify it some way to get more down force...

I just put some of your gearing in BrianG's calculator and it seems to be off a bit. I hope he comes here and see what changes he can make so it could be a tad bit more accurate. With 8S it shows 66.54mph, but with a 9% loss it is only 60mph and with 10S it shows 83.43mph, but with a 12% loss it comes out to 74mph. He should be able to make some changes to it by comparing your speeds I think :intello:.

Got that covered....its nice to have your own CNC machines....lol

Yeah when I inputted the #'s also I got those spit back at me. Not sure why the 8S is so far off. On the worst run as the batteries start to drain, it was still 69.2mph on 8S.

Sure. You already made me drool over those lipos. I'm still waiting for a Mushroom company to sponsor me so I can stop spending all my money :lol:.

I need to step up to 12S next....just afraid the motor RPM might be to much. Plus it might be a bit much for the ESC.

On 10S my truck with the 1521/1Y was putting out 4760 watts, but I'm using the Schulze 40.160. In the other thread, a couple guys were saying the HV110 can go up to 140A and with the hotter 1.5D you could be looking at close to 5200 watts if the batteries can handle that. Have you thought about 12S2P A123 cells?

No I haven't....whats the advantage to those batteries over the lipos?

I guess I need to keep my HV110 then....I was planning to sell it. Guess I better keep it then...still haven't figured out why I dropped in speed by switching to the Turnigy?

At 12S the HV110 should only be used for half the AMP rating. That's what I've heard, but I'm not 100% sure of that. I'm still waiting to get an answer from Patrick and when he get's back to me I'll ask if he can do the MOSFET changes to the HV110 that I have and if he can I'll have triple the AMP rating. The HV FETs are 12A cont. and the ones I'm looking at are 34A.

I need a controller they will handle 12S easily...with some room left. I won't be running more then 12S for the time being. If I can't get 80mph with 10S then I'm not trying hard enough. With 12S it should break 80 the way it sits.

They pack a tremendous punch and are safer. I abused the heck out of my packs and they are getting better. I accidentally shorted one pack and I got lucky, but the pliers didn't. I heard each one can easily put out 280 watts and I got almost 4000 watts out of my 36V pack. Did I say they are safer :lol:.

Get a Schulze 40.160. It's a beast.

I thought the lipo's put out more punch. I'm not worried about safety though...if it blows and takes the truck down in flames...oh well I'll build another....lol

Yeah, but they are a beast on my wallet also....hehe. I wish somebody would just take 2 Turnigy's and sandwich them together to run one motor.

Yes they do, but the A123 are tough and you can abuse them and still have over 1000 cycles on them. Proof can be found in rcgroups.com.

Man, I wish I had my HV controllers here with me. Too bad the 200A one won't be getting made.

I wish you had them too. I would buy several of them right now..I have been waiting for you to release them.

I almost flew to China to see what was going on. I was flaming after the guy told me he used sample boards and they were not able to handle the AMPs. I'm going to share some ideas with Artur and hopefully he can give us a nice controller.

I'm ready to buy...hehe. I am going to work with what I have now cause I think their is more left. Aerodynamics are playing a major role now,so their is room for improvement there.

I got some cool stuff here that I was planning on making for my truck. When I have some time I will try to get them done. My daughter might spend the summer with her grandma and that should give me around 3 months of "Me, Myself and I" time, hopefully.

Cool deal. Once I get to 80mph with this thing, I'm done with it. I will then focus my attention on the XLB buggy. Its same wheelbase and width, but lighter, so its got some great potential, but the body aerodynamics are ALOT better. To get 100mph out of a large 1/7th scale is definitely not going to be easy. That is why I was hoping your controller was out, cause I'm sure this thing will need some stupid amounts of voltage.

I got my eyes on a SHV so I can got a little insane with 20S lipos. Just have to wait for my chassis to get done. Mike already has the drawings.

Ahh you going custom chassis then?? I wanted to try to use something production and XTM has the best chassis since they are flat pan chassis and that minimizes lift under the chassis like the other big MT's.

I just don't like how the current conversions are and I had an idea stuck in my head for a few years now. I just didn't have the right program to get a drawing done. I found one and I went to work. They came out just right after some input from Mike. BTW my longest chassis will be the same length as you XTM.

Wing
 

On that XTM MMT maybe you could use a front and/or rear wing configuration to give you more down force for better control in the quest for high speeds. It may give you just a couple of mph, but it may be just the thing to help. Something like the Baja 5B wing might fit the bill. I love what your doing though. When that truck first came out I knew it would be good for something. It is a little bigger than the EMaxx, but it is built tough right out of the box. Great work with your project. Anything new????

The XTM MMT is the longest wheelbase 1/8th truck out there. Its even longer then the big CEN GST 7.7 which has a 15.6" wheelbase. The MMT is 16.5". This thing is BIG....and absolutely dwarfs my emaxx.