Can I Win!!
 

Ok first off do you guys think i can hit 50 with 4s lipo, 7XL, 125B, slipperential, 36 revo spur, 15 pinion, hb diffs, and a carbon,ti,and alu. maxx. Next a question for you guys i will be running the above set up and my friend is running 2 novack 6.5 gtb bl combos and 2s lipo on each esc also he is pretty much going all rpm exept for stock chassis and misc. alu (like bulk and other alu necessities). In you opinion what speeds do you think he will be getting. also do you guys think i can out handle him and or be faster. both trucks are going to be set pretty much the same on shock rate and ride hight. what do you guys think any advice. :028: ,:030: ,

Well, assuming you are using 5.6" tires, I figure top speed will be ~23mph. The spur/pinion, HP Pro diffs, and slipperential create a 22.704:1 ratio...

why is it so slow what can i do to hit 50 with that bl combo

what is it that makes it slow is it the gearing or what because that motor is fast and i am running 4s lipo so why so slow and how can i get to 50

What hb diffs are you running? The 3.31 or 4.3 to 1 ratio. I think brian is figuring
a 4.3 ratio.

It looks like the thing that's killing you is the high total reduction ratio. The HP diffs are 4.3:1. The slipperential is 2.2:1. And the spur/pinion is 2.4:1.

To get that speed, with all the values you listed, you'd have to use a 32T pinion. :eek:

Basically, you need to reduce the total reduction ratio. If you went with a direct center diff drive (removes the slipper though) and went with a typical 46T spur, and went with 5s (will run close to a hot 40k rpm though), you could use a 15T pinion and hit a theoretical 50.1mph (excluding tire ballooning).

Yeah, I'm figuring 4.3:1...

http://www.rc-monster.com/proddetail...d=HPI_PRO_DIFF i am talking about these hb diffs i would like to realistically hit betweenm 40-45 and i will commit to doing that any way i can with out changing electronics so if you could tell me what spur to use and all that stuff to hit 50 that would be good plus i am taping my tires so there should not be much balooning.

X-Maxx Project

1.) GorillaMaxx G2 graphite x-brace chassis $200
2.) GorillaMaxx G2 graphite chassis extension $45
3.) GorillaMaxx G3 XL battery straps $15
4.) GorillaMaxx G3 titanium hinge pin set $25
5.) GorillaMaxx G3 fasteners set $15
6.) GorillaMaxx G3 spaces set $10
7.) Ultimate Engineering servo saver generation 4 $85
8.) Flextek titanium suspension arms $200
9.) Integy MSR5 piggy back shock set (Blue) $129
10.) Integy light weight steering blocks (Silver) $60
11.) RD Logics front skid plate (Titanium) $25
12.) RD Logics front and rear bumpers with mounts (Titanium) $60
13.) RC Monster custom slipperential with spur gear $160
14.) RC Monster cnc machine speed control heat sink $30
15.) RC Monster mod 1 pinion 15T $25
16.) RC Monster ubec $40
17.) RC Screwz titanium T-Maxx screw kit $28
18.) Proline 17mm Standard wabash wheels (White) $35
19.) Proline standard size badland tires $65
20.) Proline team medium CA glue $7
21.) Traxxas revo slipper pressure plate $7
22.) Traxxas revo slipper clutch rebuild kit $7
23.) Traxxas revo spur gear 36T $3
24.) Fast Lane Machine front and rear hybrid bulkheads $140
25.) DUH Engineering Hybrid titanium front and rear shock tower set $40
26.) Hot Bodies front and rear lighting pro differential and pinions set $130
27.) T-Bonz Steel CVDs with dust boots $70
28.) Punisher Titanium 1/8 Maxx turnbuckles $50
29.) Atomic Racing Ford F-350 body with new school flames $35
30.) Ofna 17mm wheel hub set (Gun metal black) $30
31.) Hitec 5955TG titanium gear servo $115
32.) Quark Monster Pro 125B sensorless brushless speed control $280
33.) Feigao 540c7XL brushless motor $90
34.) Spectrum DX3.0 radio, receiver, and two servos $250
35.) Team Orion platinum 4800 liy-poly Batteries $300
36.) E-Cleck-Teck 40mm 5v fan $3
this is what i am using i do not minde changing the pinions, spur gear to get the result of 40 or more. but if there is absoulutly no way to hit in the mid 40s just by changing the spur gear i could possably change the motor (must be under $150) and or change the diffs to maxamizer if this helpes with speed(only if you think they will hold up) i would prefer to get the speed i want buy changing pinions and gears so lets see if we can hit that speed with that in minde and if all else fails maby i could change some of the others

you want these

http://www.rc-monster.com/proddetail...HPI_BUGGY_DIFF

the ratio of the ones above are 3.31:1 as opposed to the ones you listed, which are 4.3:1. just to let you know the stock maxx diffs are 2.85:1

Yeah, that's the diff that's 4.3:1.

Like I said, the total reduction is what's killing you. And since the Revo spurs don't come any smaller than 36T, you're kinda stuck. Even if you could get a pinion over 22T, would the motor still fit in the slipperential adjustment slots??

So even if i get the 3.31 hb diff because i am getting a slipperential i cannot reach as high speeds as with the regular trans g1 i mean

what if i get the maxamizer diffs less ratio than both hb diffs could i still hit those speeds with the electronics or will i need to drop the slipperential to reach those speeds.

yes, because the slipperential is geared toward the racer within the low to mid 30's for speed...if you all all out drag racing then you need to go a differ route, but when racing on a track it is not all about speed, yes that is nice....but you need to be able to handle it on the track as well...this is some of the things i learned at the bash

so i will be bashing but racing too it will acutally be on a parking lot racing at hobby town. so you are saying i probably will not get over 35 on the track anyway and if i do it will be to uncontrolable to mess with.

With the 3.31 diffs you can get more speed than the 4.3 models.
Would need a fairly large pinion though.

so i basically have to decide if i want speed or if i want to race there is no way to get both is there maby having a car do like 50 and changing the pinion to make it race worthy (slow it down) or something like that.

what is the higest pinion i can get to fit the 7XL without killing the esc (i am getting heatsink and 1 fan with esc)

pretty much ...yes

so i guess there is no way for me to have both speed in the mid 40s and then just be able to change the pinion and make it race ready is there. Maby stick with the slipperential get maximized diffs. and then get a high pinion to get me into the mid 40s and a low pinion for recing in the low thirties. does this sound possable with my setup.

brian it seems that when i make the balooning go up/more my speed goes up so does this mean if i dont tape my tires on the inside that they will baloon more giving me more speed.

what is the highest pinion i can get to fit the 7XL

Alright i think i have the solution to my problem tell me if it sounds good I will go with the maximizer diff cups(standard gear ratio 2.84), slipperential, feigao 540c 7XL, quark 125B, heatsink and, (2) 2 cell orion 4800(7.4v) batteries, a 20t carbon steel 5mm bore pinion, a revo 36t slipper. With this i can speeds of the mid to upper 40s for bashing and by the swap of a pinion get speeds in the lower to mid thirties for racing. and in the end i get the lower cg of the slipperential, the improvement of racing ability form the slipperential, but yet by changing the pinion i can get the speed i want for bashing. I also can get maximizer diffs which should hold up to anything. Is all of this true and should it work if so it sounds like a solution dont you think.

I guess I'll start with your first unanswered question:

There is no set max pinion size for any motor. The spur/pinion is just part of the gear ratio. If you ONLY had the spur/pinion as the means to reduce the motor speed, you'd need a really small pinion to gear it down enough. To get the total reduction, you simply multiply the diff ratio by the tranny (or slipperential in this case) ratio by the spur/pinion ratio. So, if the reduction ratio is high enough, you can use a large pinion.

Yes, ballooning will make a large difference in speed! And no, you really don't want ballooning because it's hard on the tires and traction suffers. Sure, it's cool to watch, but not healthy. :dft012:

The highest pinion will be whatever you can find that's a 5mm bore Mod1 pitch. The highest Mike has listed in his store is 20T. The problem is if the pinion is too big, the motor physically won't be able to be bolted to the mount because of the diameters of the spur and pinion together.

If you use a standard maxx diff ratio of 2.84:1, the slipperential, 36T spur, 4s lipo, and 7XL, you'll be right at 47mph with a 20T pinion.

Personally, I still think a direct pinion to differential drive would be easier, especially since you're looking for a speedy truck. I know there's no slipper, so that's a downside. However, you'd have lots more gearing options without having to use such a large pinion. And it would allow you to use a slower motor, which will have more torque resulting in more gearing options. For instance, an 8XL, HB Pro diff (3.31:1 version), 4s lipo, and 46T spur on the center diff would give you right around 49mph using a much more manageable 16T pinion. And it would still leave a little room to go up/down a tooth or two on the pinion for fine-tuning.

I don't know, maybe someone else will chime in with another suggestion. I know a slipper would be ideal, and the slipperential is a very nice product, but it may not be the ideal part for this application.

so you dont think the slipper should not be recommended even though i am racing. but anyway wat is this way to get a direct pinion to gear or is there some modification to be done can you show me and explain what you mean. this way you explained seems more logical. but if for some reason if i dont do this and i go with what i told you earlier with the maximizers acording to you calculations i can go down to 14t to get speeds as low as 34 mph for racing and 47 mph for bashing which is plenty enough speed for me. But i like this new idea could you explain with elaboration and or pictures. thanks

What I would do is e-mail Mike. I know for a fact he can get you a 24T pinion. I think a 22T as well....He should know if it will work with the slipperential or not as well.

when you say hb pro diff do mean for the direct middle diff or for the use of the diffs that go to the wheels.

The one at the wheels. For the center diff, you can use whatever one you want that'll fit the 46T Kyosho spur.

Before you take my recommendation and buy stuff, I'd wait to see what others say on the subject in case I overlooked something...

EDIT Sorry Squee, I didn't see your response.

gorillamax;

did you ever ran a model at 50 mph?

Not bashing you, but 50 mph for bashing? that's plain redicilous.. for bashing you can do with a slower truck than for racing.

If you run the 7XL on 4S at 50mph it will heat up very quick. (not good)

im not saying anything but have u driven a truck with a center diff?????? because i personally hate them lol i like to drift in the corners with the back end all out but thats just me, so i think figure out how u like to drive and then figure out gearing because the slipperential isnt cheap....

Just try a center torsen one. You'll be impressed.

Ciao,
Daniele

ok guys your right 50mph is to much for bashing with this now realized(i should have realized it sooner) i will just go with the sliperential for racing and if i do want more speed for speed runs i can put i higher pinion on the motor(i will email mike and see what size slipperential pinion goes up to) this sounds the most reasonable because it gives me the performance of the slipperential and i realized i do not need that speed after all -but fo SOME reason i do think i might want to do like 46mph i will just use the 20t pinion and i should get there. THis sounds like a plan what do you guys think. thanks for helping me realize -it seemed last night all i was thinking about was speed.

You could see if mike would make you a big pinion for it. If you go 3.31 diffs.
2.2 slipperntial and 24 40 pinion. It should run in the 40s. If you go with the
stock diffs. You will run in the 40s on 20 38 pinion spur. Just a few calculations
to go by.

Btw. I was going for mid 40s.

I ran a dual hvmaxx set up on a truck. I think the 7xl was more powerful than that. Just to let you know.