UltimaX MRB - another mid convertion

[Alex H]

Hello racers!

There are some homemade kits out there and I wanted to do one myself. Inspired by Fabs and Mr Pink.
First things first. NO 4 GEAR TRANNY:blush:. Wanted to make one myself and I am going to eventually, but just to evaluate. Have seen MR Pinks creation in real life and he is doing really well with it. It accelerates strait on slippery surfaces and turns like nothing else. And on turf, don't need to say more.

I did my transmission differently than him tough. I simply made a hole on the opposite side and reversed the axel. Put in some shims here and there and Volà. The bearing sticks out a 0.5mm. I solved that by making a 6.1mm thick CF fixture with a 10mm alutube inside that holds the bearing in place. Everything is then attached to the motorplate. The bushing are made out of 3*5mm brasstube. The whole motor/motorplate is shifted towards the right to create perfect balance L/R. Seen from behind that is. About 2.1mm shift.
The screws from the lower suspension holder (will be blue alloy soon) are longer and screwed into the brass bulk and from top as well. The lower part of the shocktower (CF of course) will be attached into it as well. Some sort of brace will also be made to support the higher end of the tower. The CF on the gearbox is for supporting the plastic and strengthen it.
Just waiting for the CF sheets to arrive so I can start on the chassi and tower. There will be no top-deck and side by side liposaddles only. http://rsb.se/gallery/files/2/6/4/6/img_1333.jpg
More to follow soon:D.
http://rsb.se/gallery/files/2/6/4/6/img_1334.jpg

[OldTimer]

Looks good so far :thumbsup:

[Alex H]

Thanks:D.

I forgot. I am going to steal your CR2 chassis solution with CF screwed together Jonathan:thumbsup:.

[RogerM]

Is there a webcam in my workshop??? Rear end looks similar to the car I am looking at right now but with the motor plate on the other side and a 4th gear (similar to the CR2 idler gear mod).

Question is do I take it to Petit or not?

[Fabs]

Alex,

Looks good mate, but I have a question: where does the shock tower go??

Roger:

Of COURSE you bring it !

[Alex H]

Alex,

Looks good mate, but I have a question: where does the shock tower go??



Thanks Mr Mid Ultima Custom special!

If you look closely, you can see the brass bulk between the upper suspension holder and the rear arm mount. Going to drill 4 holes in that. Going to use 3mm Cf for the tower and mill 1mm off where the upper shock holes are to 2mm. This straitens up the shocks and they clear the turnbukles better. Then I have a solution for another 2 holes a little higher up on the tower for greater support so the transmission does not break easily. The 4 holes in the bulk is not enough I think.

What's great with this tranny mod is the fact that there is very little preparation on the gearing house ones you figured out what spacers to use and what holes to make. Only had to reem up the new opening to 10mm and shims it correctly. If the transmission case breaks it will only take a few moments to make a new one:thumbsup:.

Have another idea too. The Durango Dex410 front shocks are not that much shorter than the Kyosho rears. Perhaps 10-12 mm. Have not messured yet. This could mean lower CG and improved airflow over the wing. Got enough Cf for an optional shocktower....

[Alex H]

Transmission finally done!!!:woot:. Some blue option parts to top everything.


Chassis next..
http://rsb.se/gallery/files/2/6/4/6/img_1336.jpg

http://rsb.se/gallery/files/2/6/4/6/img_1337.jpg

[Alex H]

The result so far. Next up is the fixture part that will hold the lipos and give some more stiffness to the chassis. No topdeck.
There will be 3 of those brass bulks. For adding weight (54grams) and hold the motorcables. The brace from the tranny will be fitted on to that as well for extra support. On top of them I will have a CF for support and looks.
http://rsb.se/gallery/files/2/6/4/6/img_1341.jpg
http://rsb.se/gallery/files/2/6/4/6/img_1340.jpg

[GRIFF55]

Looking GOOD!!!

[Garry Driffill]

Im likeing the whole hiding of wires bit, thats one thing that annoys me on these mid motor cars the wires over the cells like that, but hidden away like that is really clever..

When i had my Atomic Carbon S2, the pre-tub chassis i hid all my wires between the cells once and it was soo much more easy than having them up top and i feel "Messy-like"

Good job man! :wub

[Alex H]

Happy you like it:D.

I am very allergic to messy wiring. Absolutely hate it and just looks so terrible inside mid-motor cars. Had to sacrifice 8mm of the chassis for it, but it is worth it.
Have some cool ideas for keeping it clean inside later;). New thinking and good looking too.

[GRIFF55]

don't forget the sensor lead!!

[Alex H]

Yeah, I know. That little sucker could not fit In those small holes. Do not worry. It will be solved.

Almost finished here. Fitted an extra 2mm cf to stiffen everything up and it does also serve as a lipo retainer. The whole thing is very stable and I believe it will hold together.
Still to be made.
*Batteryposts
*Fine tune the CF with sandpaper and CA.
*a new motorplate that excepts the gearcover without having to cut into it.
*A body and undertray
*Fitting electronics
*Testing the living daylight out of it!!!

Here some pics. Let me know what you think. :D
http://rsb.se/gallery/files/2/6/4/6/img_1343.jpghttp://rsb.se/gallery/files/2/6/4/6/img_1347.jpghttp://rsb.se/gallery/files/2/6/4/6/img_1346.jpghttp://rsb.se/gallery/files/2/6/4/6/img_1345.jpghttp://rsb.se/gallery/files/2/6/4/6/img_1344.jpg

[GRIFF55]

looking very nice indeed. How about slotting the brass blocks at the bottom so the sensor lead can run under there before bolting them down?

[Alex H]

Spasiba!

Not really sure how you mean Griff. Please explain further.

[erkan]

just cut the middle part out between the holes so you get one long hole instead of 3 round ones.. then you can slide the sensorcable/plug through and then place the cables.

how hard can it be alex? ;)

[hottuna]

Alex, he means like this. Make a slot in the bottom of the block
Gå och lägg dig nu Peter ;)
Promillevarning på ritningen :thumbsup:

[Alex H]

Have been over those solutions a couple of times already and there is no space left. First up I did a "tunnel" with 2 CF plates attached on each side of two 4mm*6mm brass U-profile that worked as top/bottom.
The problem was that there were not much material to make the threaded holes. Too week. If I only had a 4*4mm brass. It would be just perfect and a lot more space inside. Could not find that thin. Only 10*10mm:(. Perhaps I will make them myself at a friends house to solve this issue.
My workshop is my kitchen. Only tools available is a Dremel and a hand held drilling machine.

If I want to replace the motor or something else I only have to loosen the two screws on the back bulk underneath. The front only has one screw so it can be turned;)

This is how it looks. Probably going to use thinner cables. This has A LOT of isolation!
http://rsb.se/gallery/files/2/6/4/6/img_1351.jpg

[Dyna]

I have to say ive been watching all the RB5 mid conversions very closely, and considering your workshop is your kitchen with very basic handtools, this is a superb effort - over the years ive seen supposedly professional conversions & parts a lot rougher than yours. Very, very impressive.

Looking forward to seeing how it runs now ;)

[GRIFF55]

I meant like hot tuna has drawn, but looking now it would leave no fixing points.:(.

[Alex H]

I will solve this by opening the bottom two holes so they become one larger oval shaped one and then I found some more regular sized wire that does fit in there better. The one on the pic are way yo FAT!
Have a 150mm sensor wire from LRP. Super flex and super thin:thumbsup:. Perfect length.

[OldTimer]

Run a sensorless speedo :p

Coming on really well alex, btw the lipo straps will also reduce flex if they are a tight fit onto the posts, but you might want to look at some bracing towards the front end, if your running 4mm cf you might be ok.

[Alex H]

Yes, I am actually running 5mm in front of the lipos and to the front 3+2mm. Solid CF, except where I have cut out around the servo. The post that supports the front end, next to the servo is at the moment 6mm brass but tonight I am going to a friends place and they will be replaced with 8mm Alloy ones that are milled down to 6mm in top to fit in the slot. Think this will give really god support to the front end also. The whole thing is really stable.
Regarding the battery posts I have a One nut solution instead. show you later this evening;)

Thank you guys for all your input. Really nice to get advice from people who has got the knowledge.
http://www.qtl.co.il/img/copy.pnghttp://www.google.com/favicon.ico (http://www.google.com/search?q=One%20nut)http://www.babylon.com/favicon.ico

[OldTimer]

I used 5mm on the prototype S4 and works fine :thumbsup: so on a lighter 2wd will not cause you any problems.

[Alex H]

Heres some more pics.

Very happy with the result so far. Only the front posts to be made still.
The som fine tuning and hit the track:D.
I made the sensorcable fit inside as well and I could not find my 150mm so it had to be a long one instead:(.

And the Lipos wont fall out. It is a very, very tight fit and the brace is 5mm thick so they stay in place.

Now I have to wait until Sunday so The premier can take place.
http://www.oople.com/forums/picture.php?albumid=469&pictureid=2767
http://www.oople.com/forums/picture.php?albumid=469&pictureid=2764
http://www.oople.com/forums/picture.php?albumid=469&pictureid=2765

[ace028]

That looks awesome man, can't wait for a report on how she handles, I love inginuity! Great work, great work.

[Alex H]

Thanks!
Had to try it out on a big factory floor that was really dusty and slippery and I have to say I am surprised how straight it went during acceleration and how easy it was to control! Could throw the rear out and make it drift a little:D. Everything seems to hold together and I am hopeful for the upcoming race the 29th this month.

[GRIFF55]

Did you run it with those front tyres on???? put some 2wd fronts on it :thumbsup:

[Alex H]

I did not run those tyres!
Those are for our indoor series and we run them like slicks with additives on them. I tested with holeshots and wide 4 ribbed losi tyres.

I am currently designing a new transmission. It will be in aluminium and it will be reversible. Not mid or rear, but left or right hand. The guys who run the X-6 indoors here have put in the old 3 gear transmission and it works out great for them. So Mine will have both options in the same case. Expensive, I know but this is fun:thumbsup:

[Alex H]

Very happy today. Made it t A-main in the first real test with the car. Took the seventh spot. The car ran great even tough there is room for a lot of improvement in setups. Did not dare to change anything ones I made it to A main. Many nice remarks from people on the build and handling of the car.

Now version 2 is on its way and it will feature a 4gear transmission and the shocks placed like on the cougar. In front of the drive shafts. Much because I want to move the wing more forward and place it more directly over the rear. Then there will be three layers of Cf where the top layer are shaped after Azarashis Vaykal shell.
I post a new thread about it when the whole build is done and ready.http://www.qtl.co.il/img/copy.pnghttp://www.google.com/favicon.ico (http://www.google.com/search?q=two)http://www.babylon.com/favicon.ico

[Lowie]

nice work, dude, and i love the very simple but effective gearbox-conversion.
Nice!

[mr. ed]

...
I post a new thread about it when the whole build is done and ready.http://www.qtl.co.il/img/copy.pnghttp://www.google.com/favicon.ico (http://www.google.com/search?q=two)http://www.babylon.com/favicon.ico

Drop a note in this thread when the new one is up please.
I really like your work.

[Lowie]

Say Alex.
i noticed you used some type of rubber mud-caps over your rear outdrives.
Can you give me some information on brand, type, partn° of those mudcaps?

[Mr. Pink]

Say Alex.
i noticed you used some type of rubber mud-caps over your rear outdrives.
Can you give me some information on brand, type, partn° of those mudcaps?

http://www.oople.com/forums/showthread.php?t=37088

Team durango...:D