7xl preformace
 

i was woundering what kind of preformance i can expect with the Feigao 540C XL Brushless Motors 7xl in an e-maxx with the warriour 9220

What batteries will you be using with it? How many cells?

ib4200 12 cells

The 7XL is rated at 2382kv so with good cells at say 1.2v per cell (per their website) you would get a no-load speed of 34,300 rpm. That compares to a no-load speed of approximately 19,000 for the stock tritons. The torque difference and "punch" will be astounding as will the top speed. Top speed should be around 48-50mph.

Cool hand or Squee can correct me here if my calculations are off at all.

what gearing would i run and do you have the motor

I'm going to defer that question to "RC-Monster" Mike. He has a way to calculate the preferred gearing. I'd hate to steer you to the wrong pinion. I will tell you that the preferred set-up is to go with the UE/Strobe Slipper which I believe is a 51T spur gear. This slipper handles the power the 7XL will dish out.

Id start with 18/51 with a 7xl on 12 cells.

What diffs are you running?
What kind of tire you running as well?

I agree with Sylvester. 18/51 would be a good start. If it runs real hot, you can always gear it down. And yes, it depends on the diffs.

i run stock diff and bowtie tires

I would seriously consider upgrading the diffs! You'll likely blow them to pieces with the new power especially landing off jumps when "on the throttle".

1) Install FLM or Kippster difff cups w/ robinson racing gears and GA diff cases

or

2) Do the UE 6 or 8 spyder diffs. Expensive but bulletproof.

i have some titanium ones shiping to me

Ti diff cups? Diff housings?

You do have MIP ur UE CVD's right? Anything else will likely "grenade".

housing and mip cvd

Really?????????????
 

Now you've got my attention...............

Where did you find Ti Diff housings and/or diff cups????????????????

Please share!!!!!!

I thought Nova made Ti diffs? Do they not?

All the Nova's I've seen have been aluminum. Can't recall if they are 6061 or 7075 but aluminum. I was surprised b eacuse I've never heard of anyone making Ti diffs. The material is way too expensive. Imagine the cost of 1" Ti bar stock per foot! OUCH! And Ti diff housings would be way out there! The price of 3/4" plate Ti would be absolutely frightening!

A little off topic, but when someone mills out a lot of material, can the excess shavings be sent somewhere to be re-melted down? Seems like a waste of material otherwise...

6AL-4V (Grade 5) is $903.00 for a 1' round x 6' length.
6AL-4V (Grade 5) is $2,057.00 for a 3/4" x 2" x 6' length.

In large quantities price goe down but it gives you an idea how unlikely larger Ti parts are to run across. Ti is also a BEAR to machine compared to aluminum and requires different machine tools, machining lubricants, and machining speeds.

Brian,

Scraps are "recycled" but the value of the scraps or shavings is not great. Around $0.55/lb for aluminum currently.

i had my dad who works at todd ship yard make dulicteof the stock diffs out of ti he shiped them because i wont see him for 2 weeks

Even so, it would be nice to know that it isn't wasted. Although, I was speaking more about Ti recycling, but I imagine the idea is the same...

the reason my dad built these diffs is that he knows how easy it is to bend aluminam

Awesome!
 

I think it's safe to say that few if any have Ti diffs! Very, very Cool.

I am a bit jealous though! Would he be willing to make more? Hint, Hint. Sure would like some Ti diffs!

his boss got mad because he used this tool that compresses water so hard that it cut it out and it took around 4 hours so that would be a no

A Flo-Jet? Oh, BTW, the Nova's are 7075 I believe.

Yea, the novas are 7075, thought there was a Ti diff company though. Maybe i just got confused with 7075 vs Ti.

Yep, cuts like a plasma cutter only with super compressed water that contains abrasive. Leaves the edges of the cut part burr free too!

Back to the original questions...

What type of transmission mods do you have? The 7xl will eat your plastic idlers for lunch! If you don't already have them pick up a set of steel idlers from Mike here at RC-Monster $27/pr or the UE's for $32 if they are in stock.

Procharged, would you please be so kind to use the edit button more frequently?

I was just reading thru this post, and it seemed so hectic. Thanks for your understanding. I can imagine you where getting enthusiastic though :p

Normally a product is payed in the weight of the material that the actual product is. not the weight of the bar it was made from. (at least, this is the case here in Holland at a few places i know)

With titanium the price of the material isn't the thing that makes a thing as a diffcup so expensive. It's the intense machining..

I drive my 7XL on 14 cells with the following upgrades;
rear UE shafts, center MIP's front shafts i kept stock (you want a bit of flexibility with those stock diff gears) I also use the Gmaxx singlespeed, and even with that, i wasted a stock idler (the singlespeed takes the huge play out of the drivetrain a normal 2 speed transmission has)

I prefer the idlers from mike over the UE's, the ones Mike has run smoother. (and logical, more silent too)

The 7XL on 14 cells is a true monster.

I wouldn't use tires, such as mulchers. They are very, very hard on the drivetrain.



it's not the diffcups that are a concern. It are the gears that sit inside the diffs that are.

It's wise to get a handful of shims and mesh the gears as tight as possible without binding. Also; don't use silicone oil in them, it will leak out, and get in your bearings. the last place you want the silicone oil to hang around..

Serum,

1) Not sure what you're referring to with respect to the edit button.

2) The price of Ti barstock ABSOLUTELY plays into the cost of the final product as well as the machining which is no more intense but does require special cutting tools, lubricants, and machining speeds as I previously mentioned. This also drives up the cost since Ti is hard on machine tools.

3) Flex in the diffs (cups and cases) does in fact play into their early demise on high power maxxes. Improving the quality of the diff gears & pinions is always a great upgrade, no question there.

4) The UE gears are very well made but for perfect mesh and silent running you need to lightly de-burr/polish the teeth which have an ever so slight burr from the machining process. A quality lube also makes a difference. I've been working with two major performance oil manufacturer's on a lube for RC transmissions (thru my drag racing & NASCAR affilliations). I may market the product at some point in the near future. It's in beta testing right now.

As to the edit button: after you post, there is a button at the bottom right side of your post that says "edit" right next to the "quote" button. If you wait too long (don't know the exact interval) the button goes away though.

Brian,

Thanks. I'm aware of and do use the edit button. My question to Serum was what it was he thought I was supposed to edit. I fail to see what was so hectic & chaotic about the posts.

I think serum was refering to the 11;35 then the 11;38 post back to back.

Could be.

The posts were addressing different things, but whatever. I'll try and be more mindfull of my posts so no one gets "upset".

:010:

That one Leroy refers to and the 12.04 and 12.05 post. So those two non-edited posts made me say what i wanted to say. If you disagree, you can PM me about it.

I see you think i am nitpicking on you. Which is not the case. I was just sharing it and i didn't want to make a point of it. Perhaps it would had been more appropriate if i PMd you about it. but again, i wasn't nitpicking, i was just saying something to you like i do to all other users that post replies right after each other.. Some users don't like to get a PM about something like this, so it's rather hard to judge a person on a few posts.

What do you think is the price difference with a difficult part to cut like a diffcup? (this is what we are talking about) if made in small quantities, I don't think the price of the material will drastically increase the price of the product. It's the machining and programming that takes the biggest part of it. So from that point of view the material isn't good for the biggest part of the price.

I use a dry PTFE lube inside the tranny and it stays butter-smooth.

about the diffcup, i should had been more clear; i meant that an aluminum diffcup is good enough, (like the FLM you are using, which i read in your signature) no need for a titanium one. (because you where asking him if he could have his dad made you some) a 7075 cup covers the load more than enough. (obviously better than a 6061 cup) And from that point of view, it are the inside gears that are the weak link.

will these cvds handle the force of that 7xl http://www.rc-monster.com/proddetail...=TBTM01&cat=17

I am hearing mixed stories about these shafts. one loves them, while another one keeps braking them.

The thing with MIP or UE shafts is that you can use them in the future with 1/8th diffs. these are too short.

Emaxx Driver,

Invest in the UE 6mm or 8mm CVD's and be done with it. If money is an issue buy the MIP's or perhaps the Tsais T-Bonz Mike sells. Simple as that. I have not used the T-Bonz but I doubt Mike would sell them if they were not up to the task. I would avoid both the RD Logics and the metal splined versions based on personal experiences. I've seen the splined versions spilt in the splined area on a .28 powered T-Maxx.