Hey Promod! Nice to hear from you. The speed King himself.
What do you think about the dual 7XL setup with two 5s LiPos for speed runs?
What would you put in there for a dual setup if cost were no object?
Thanks.

A pair of 1950 6t would be about same kv but with more torque so could gear it up a little more maybe see 65 or so.

650 dollars for a pair of 1950. Pretty much for speed runs.

Will the 7XL's still work with my 9920's?

They should still work

JOHNNYMAXXIMA, you may kind it most cost effective (and possibly more fun) just to strap some fireworks to the back of your truck. Speeds would be similar....

that probably would be cheaper but i dont think you would have to much control over it.
we actually launched a few fireworks off my neighbors pede and then my mom :028: came out and yelled at me because we were doing it to close to our neighbors house

Hmmm. Kinda like the idea of that firework thing.
Anyone else know if the 9920 and 7XL are compatible. I'd kinda like more than a "they should still work" before I make the plunge.;)

Lots of people have ran the 7XL on a 9920. There shouldn't be any reason why it wouldn't work for you as a dual setup.

The 7XL/9918 was the hot ticket for quite some time before people started experimenting with huge cell counts, 8XLs, 9XLs, etc... and the bigger Lehner motors. A 7XL is pretty ideal on 12-14 cells.

I currently run 2 trucks with XL motors,an 8XL with a 9918 and 4 lipo cells and a 9XL with a 9920 and 6 lipo cells,with no problems.Tons of torque and major topend.

I have ran a 7xl on a 18.97 schulze and a 9920. It will work johnny. Especially on your truck cause the motor will have less weight to pull by it self. !5lb maxx with 18 cells and a hi gearing. I think yours will be fine.

You run those XLs in TXT-1s?? Sweet!!!

Got any pics?

johnny, do you worry about runtimes over speed? if you dont plan on going over 14 or 16 cells you might want to think about a 6xl. on 5s lipo you would probably get somewhere close to 65 to 70ish if your lucky....

i would say a twin 6xl would reach 65 or 70mph but getting tires to stand that speed and weight would be challenge

what weight? lol he would be using lipos so i wouldnt be worried about weight to much although some duct taped tires would be a good investment...

even with the lipos it would be close to 12 lbs i would think the 6xls would be nice and fast though

See, now that's what I'm talkin about! Keep talking about something long enough and sombody's bound to come up with something better.:004:
My main concerne is top speed, I don't care about run time at all, so if 6XL is the way to go, then I'm all for it.
My brother has an 18MT that does almost 55mph and he says my truck would never beat his, so if I could embarress him with my Maxx that would be great!
My truck is weighing in on the higher part of 14lbs. as it sits, so I'm guessing that LiPo's will take off about 2lbs. roughly? Might have to put her on a diet to get the weight down a little more.
So is there anything faster than the dual 6XL's and 5s' that would still work with the 9920, or am I tapped out as far as speed goes with the 6XL?
Thanks.

There is johnny but not for the dual. A single big motor on the 2x5s lipo would kick some serious booty. If you want to try the 5s lipo on the 9l s you could. I have seen a 8l on 18cells. There has got to be a faster set up. YOu could lose the tranny for a center slipper for the higher gear ratio. and a little weight as well. Why only 5s lipo? 7 xl on 6s lipo would push you faster than the 5s. For nothing but speed why not.

edit: I ran some numbers. with the stock diffs, 6xl , 5s lipo, 20 51 gearing with the strobe, tranny in second gear, with a 140 mm tire.
top speed estimated at 67 mph. I don't know if the 9920 will take a 6xl with that kind of gearing. 7xl on 6s lipo would put you in 66 mph bracket with a 22 51 gearing. Let me see what other combos you may want.

Wow, that's pretty cool Leroy. Thanks for doing that. As long as I can get at least 60mph that would be cool. Should the 7XL and 5s be capable of that?

It would have to be geared higher like a 23 51 gearing. with 7xl and 5s lipo

7xls are doable, Johnny. I wouldn't try the 6xls, though. With gearing, the dual 7xls on dual 5s Lipo will be quite a rocket.

5s lipo aint' gonna get you to 60mph. Sorry, no can do. You need over 2000 watts to get to 60 mph in a maxx. 5s lipo - if you use the Kokam 3200's... won't do it - at least not w/o major voltage drop or battery damage.

You need 8s, 9s, 10s lipos to get into the 2000 watt+ range comfortably. I never hit 60 mph until I went to 8s lipo. I went 8s 3500 mah packs. Even then, I had to pull like 80 amps continuous to do it! My next project is going to be 10s 4400 packs that are 12C continuous nad 16C for 10 seconds. That would be pretty sweet.... 37 volts at 70 amps is about oh.. probably gonna get close to Promod's 70 mph. (evil grin)

BTW, the 60 mph run was with those STOCK TIRES AND RIMS. The ballooning actually helped increase the top speed due to taller "variable" gearing. But those things got major rolling resistance problems. I've noticed that the louder the road noise, the slower the vehicle - I guess that makes sense. Energy is wasted producing sound.

Sorry, re-read the thread... 5s on each motor will be enough power. If you truly go 5s2p, you'll be capable of 70 mph if you gear properly. :) good luck!

At those kinds of speeds and weight, you can do some serious damage so be careful!!!

But you know... a single big motor and controller will be lighter and more efficient than dual motors, dual controllers, etc... Why not 10s Lipo and a bigger Lehner motor? 22 series? Wait a minute... starting to sound like Promod's setup now. Heck, go 12S lipo - 6 on each side and get a 40.160 controller. Nobody can touch you then. You'll go 60 w/o even getting warm. You can probably even do 80 with 12S lipo.

wow. How fast do you think two 3s2p packs on a 9xl will do?

there you go Johnny you heard it from the man

Thank you all for your help!

Lipomax-
You totally took the wind out of my sail with your first post!:026: Thanks for clearing it up on your second post.
I'm going to stick with dual BL on this Maxx and just may take your advice on the Lehner 22 series on my other single BL Maxx in the furture. That sounds like it would be a fun setup. Especially because of the fact that my single BL Maxx weighs almost half of the weight of the dual setup.

Just ordered my batts. I went with two Maxamps 5s packs. Bought my power supply today also. Just waiting for the 7xl's to get back in stock along with the new 989 Super Brain chargers and I'll be ready to rock! Gonna get me a new video cammera as well so you guys can watch me crash the thing again.

Anyway, will my RC-Monster heatsinks that I have on the 9L's fit on the 7XL's?
Thanks.

to get the heat sinks to fit the xl you will need longer screws.

yea, no mods just longer screws in the rear, Johnny, what mAh of lipo did you order? 3200's?

Thanks guys.
No Sylvester, I actually got the 4000mah. :027: A little more run time with those, yes?

johnny, if im not mistaken they wont fit without some REALLY long screws unless you have the L length heatsinks although if im not mistaken its the S length. if your not sure on which ones you have just see if its the same length as the can or shorter. if its shorter its the S.

i'll be interested to see how your gonna fit that in a gmaxx. The gp3300 already barley fit (they got in the way of the servo, at least for me it did).

Yeah squee, I do have the smaller one. I guess I will have to get some longer screws then.
Supermaxx, you will be interested to see how I will fit what in a g-maxx? The LiPo's? And yes you are right, the 28cells that I have in there now barely fit.

It would seem pretty hard, but those maxamp lipos are only 130mm long.

My packs now are 160mm long so shouldn't be too hard for 130mm to fit in there.