Dr Jim's Limitless Build

[drjim]

GEEZ.....I just gotta update my build thread more often!

Gotta whole bunch of parts I have to install, along with my motor cooling fan mount that @Mongoose gave me. Thanks, buddy!

And now that I have wire and bullet connectors, I'm going to swap out the BLX185 ESC I have for my MM2. I really don't like the brakes on the BLX185, as you can't set them to more than "50%".

And since I got the Castle Program Card, I should be able to read out what the ESC is doing during a run.

Still waiting for my 6.5mm bullet connectors so I can finish the motor-to-esc cables I'm making for the MM2.

My bearings from "Jim's Bearings" are scheduled to arrive Friday, and I'll use a few of them when I install my super-duper, ultra-cool billet parts from PPS.

Thanks everybody for the help, great advice, and posting your own builds.

You guys are an inspiration to me!

 

[drjim]

Got my Yeah Racing fan mounted to the 3D fan mount @Mongoose sent me.

This thing is so clever it hurts! I was worried about strapping it on, and as I fumbled around with it under my illuminated magnifying lamp, I noted it had a "tunnel" or channel printed in to it to pass the cable ties through!

That's just too cool!

Got it strapped to the motor, and tightened down the cable ties once I had it positioned where I wanted it.

Then I took most of the aero out of the rear wing, and trimmed the fronts a bit, too. Still have some "hand finishing" to do so they're not all cleaned up and purdy in the picture.

I'll probably go down to the last molded-in line on the rear one, and we'll see how it handles with the fronts cut down. I don't want to just leaved them off, as the side plates on them should contribute to straight-line stability, but for now, while I'm learning to drive it, I wanted to keep some of the aero it came with.

And then I drooled over these bits some more:

Thanks @Mongoose for the mount, and thanks to the guys at PPS for making such killer products!

 

[drjim]

Trimmed down the front and rear spoilers last night, and sanded all the edges. They had some pretty rough edges, and I don't like sharp things on my cars.

I know the prevailing wisdom is to trim the rear one flat, and remove the front ones, but since I'm a rank beginner with this high-speed stuff, I'll accept the added drag to get some downforce, and I think the front side plates will give it a touch more staraight line stability.

And I trimmed down the "wall" at the front of the battery packs.

The packs I'm using have the leads coming out of the end, and with the wall at the full "as made" height (I took about half the height out) I had to put a sharp bend in the leads to make the packs sit flat. I just don't like putting a lot of stress on the battery leads, and now I have plenty of clearance.

And I now have enough connectors and wire to make up some new leads, and get my MM2 installed.

More fun to follow!!

 

[jondilly1974]

One bit of caution, the extra rear downforce could make the front lift at speeds of 80mph or higher. It has a lot of leverage way back there. You don’t want air under the nose at 80mph. ??

 

[drjim]

One bit of caution, the extra rear downforce could make the front lift at speeds of 80mph or higher. It has a lot of leverage way back there. You don’t want air under the nose at 80mph. ??

I'm considering taking the rear down one more level.

Does anybody run a real wing on these? By that I mean an inverted airfoil. These are more like spoilers....they kill the lift, but cause a lot of drag.

 

[jondilly1974]

I'm considering taking the rear down one more level.

Does anybody run a real wing on these? By that I mean an inverted airfoil. These are more like spoilers....they kill the lift, but cause a lot of drag.

Not many I’ve seen. Most run a flat carbon fiber wing with a very slight pitch.

 

[drjim]

Not many I’ve seen. Most run a flat carbon fiber wing with a very slight pitch.

Do they generally run end plates or winglets?

Thanks for the guidance and clarifying a lot of things. Backyard Bashing is great fun, but these speed runners have me hooked!

 

[jondilly1974]

Do they generally run end plates or winglets?

Thanks for the guidance and clarifying a lot of things. Backyard Bashing is great fun, but these speed runners have me hooked!

Yes usually end plates that are also the mounting location too.

 

[Porschetech🇬🇪]

Damn. Someone’s been busy modding ?

 

[drjim]

Damn. Someone’s been busy modding ?

I prefer to say "Optimizing".....!

 

[Porschetech🇬🇪]

I prefer to say "Optimizing".....!

I blame it on the lockdown ?

 

[drjim]

I blame it on the lockdown ?

Or the fumes from the solder flux.....

 

[adidas303]

I may have to bother ya, make a trip up north to ya and we do up some speed runs!! ? ?

 

[Mongoose]

Got my Yeah Racing fan mounted to the 3D fan mount @Mongoose sent me.
View attachment 72581

This thing is so clever it hurts! I was worried about strapping it on, and as I fumbled around with it under my illuminated magnifying lamp, I noted it had a "tunnel" or channel printed in to it to pass the cable ties through!

View attachment 72582

That's just too cool!

Got it strapped to the motor, and tightened down the cable ties once I had it positioned where I wanted it.

View attachment 72583

Then I took most of the aero out of the rear wing, and trimmed the fronts a bit, too. Still have some "hand finishing" to do so they're not all cleaned up and purdy in the picture.

View attachment 72584

I'll probably go down to the last molded-in line on the rear one, and we'll see how it handles with the fronts cut down. I don't want to just leaved them off, as the side plates on them should contribute to straight-line stability, but for now, while I'm learning to drive it, I wanted to keep some of the aero it came with.

And then I drooled over these bits some more:

View attachment 72585

Thanks @Mongoose for the mount, and thanks to the guys at PPS for making such killer products!

Lookin good @drjim! The mount looks good on there! I feel privileged that it’s up to standard for this awesome build!

 

[SrC]

I just bench tested my Lim. Installed esc and motor , calibrated the Radio etc. with a 4S lipo .I ran it on the bench,the rear diff was bricked. Did you have any issues with your diffs? Its locked with no chatter or noise. Lost alot of diff fluidJust when I thought I could get a few maiden runs in it now needs a diff rebuild. Mine was an early production, just took out the box new recently.

 

[drjim]

I just bench tested my Lim. Installed esc and motor , calibrated the Radio etc. with a 4S lipo .I ran it on the bench,the rear diff was bricked. Did you have any issues with your diffs? Its locked with no chatter or noise. Lost alot of diff fluidJust when I thought I could get a few maiden runs in it now needs a diff rebuild. Mine was an early production, just took out the box new recently.

No, mine appeared to be fine when I ran it on the stand. They're pretty noisy, but then this is the first rig I've ever owned that operates at this power level.

The only thing that's happened so far was a screw backed out of one of the front A arms, and I noticed some play in it. Figured out which screws to check, tightened all back up, and the play was gone.

Had a bunch of "Home Owner" stuff to do today, then I made a big batch of cornbread. I'm going to seriously get into it Sunday, as all my chores for the week are finished.....!

Lookin good @drjim! The mount looks good on there! I feel privileged that it’s up to standard for this awesome build!

HAH! You flatter me! I'm just trying to break 100MPH without breaking the bank. One of these days I'll total it up, but I know it's under a grand. I've only got about $650 in my little VTA car. I'm not doing anything else with my Senton because it's a 550 Mega, and I'd rather just get another Arrma for bashing than dump money into it.

 

[Joelk]

I just bench tested my Lim. Installed esc and motor , calibrated the Radio etc. with a 4S lipo .I ran it on the bench,the rear diff was bricked. Did you have any issues with your diffs? Its locked with no chatter or noise. Lost alot of diff fluidJust when I thought I could get a few maiden runs in it now needs a diff rebuild. Mine was an early production, just took out the box new recently.

I had a diff come from Arrma locked. The problem was that the cut on one of the cross pins was off center. Replaced that cross pin and it was good to go.

 

[SrC]

I had a diff come from Arrma locked. The problem was that the cut on one of the cross pins was off center. Replaced that cross pin and it was good to go.

Thanks for the heads up. I have not taken the diff out yet. But that confirms my guess also. That would explain the diff being locked as well as all the diff fluid leaking out with o-ring not seated (oil leak) and the sungear jammed (Diff locked).
I will cut some new 2.2 mm HSS drill bit shanks later to replace these stock pins.. Bought a batch of drill bits for all my pins.

 

[drjim]

Release The Hounds!

I'll be busy for a few hours..........

 

[drjim]

Got the center spool shimmed. I used an "MS" washer on one side (the left here), and a .5mm diff shim on the other.

And bolted in a few new things....

Shiny!

I'll put the pinon back on the motor after I drop the spool back in. I'm really lovin' the way PPS uses the long screw thread to adjust the gear lash.

Brilliant!