1991 Detroit Losi prototype – tribute car.

[Johanp]

In mid August I stumbled across a Youtube clip called “Losi´91 Detroit Conversion Kit – First Track Test Day” published by Grand Prix 3D.
After watching the clip a couple of times I emailed Andrew at GP3D and placed a pre order for at kit.
I still remember taking the bus to the magazine store every month to buy RCCA back in the day. And still remember reading the article and looking at the pictures
of Kyle Reed´s Losi Detroit worlds prototype car. Unfortunately I don´t have the magazine anymore.

A couple of weeks ago the kit arrived. I ordered the kit including the “hybrid chassis" containing a carbon lower part of the chassis and an upper 3D printed part.
Included in the kit was also templates to use for modifying a molded chassis. I have a well used Junior 2 spare chassis that I can use so I decided to go that route.

It took a couple of deep breaths before I picked up the hacksaw and started to cut into the chassis.

The templates are also a guide for drilling.

The chassis is now left with my brother for machining, I just got this picture from him:

I have been waiting since 1991 to build one of these, so I´m going to enjoy myself and allow this build to take its time.

[mikea96]

I will definitely be watching this thread.

[Charlie don't surf]

Mike, were you the one that got the Worlds prototype front rims from me years ago? This is what they are for!

[mikea96]

Wasn't me but i have always wanted to build this car.

[Johanp]

Quick update.

Chassis machining not finished due to the machine is being moved.
Gearbox housing have been modified by removing the attachment points for truck body mount.
All hardware is being cleaned right now.
I have collected everything I need besides the original "short" ball cups.

Most of the collected parts are used. This combined with that I ordered spare chassis hinges, steering arms and front arms from GP3D means I plan to run the car when it´s finished.

I have a picture of what I think is Joel Johnsons 91 prototype.

Looking at the lower right picture this car has the slider driveshafts. This solves my problem that I do not have any universal driveshafts for the Jrx2 platform.
I do however have a new set of the white plastic sliders that I can combine with the dark grey ones to recreate the driveshaft in the picture.

[TRX-1-3]

Quick update.

Chassis machining not finished due to the machine is being moved.
Gearbox housing have been modified by removing the attachment points for truck body mount.
All hardware is being cleaned right now.
I have collected everything I need besides the original "short" ball cups.

20241128_094433.jpg

Most of the collected parts are used. This combined with that I ordered spare chassis hinges, steering arms and front arms from GP3D means I plan to run the car when it´s finished.

I have a picture of what I think is Joel Johnsons 91 prototype.

JJ_xxproto.JPG

Looking at the lower right picture this car has the slider driveshafts. This solves my problem that I do not have any universal driveshafts for the Jrx2 platform.
I do however have a new set of the white plastic sliders that I can combine with the dark grey ones to recreate the driveshaft in the picture.

This build is gonna be frickin' sweet! Cool to see the milling template conversion option being utilized. Something I've heard or read over the years regarding the slider half-shafts is the white (super sliders?) halves were intended for use with a gray half. Something about reduced friction with dissimilar materials. But, being a Losi afficionado, you probably already know this.

[Johanp]

This build is gonna be frickin' sweet! Cool to see the milling template conversion option being utilized. Something I've heard or read over the years regarding the slider half-shafts is the white (super sliders?) halves were intended for use with a gray half. Something about reduced friction with dissimilar materials. But, being a Losi afficionado, you probably already know this.

Thanks!

You are correct about the driveshafts.
They are supposed to be used one white half together with one grey half.
I don´t know about being a Losi afficionado...but I learned about never having two details made out of the same plastic material touching each other when I used to design mobile phones for Sony Ericsson a long time ago. This will/can create a creaking noise due to friction between the details. Using different plastic materials will decrease the friction. (Sorry about the nerdiness...been working as a mechanical engineer for 25 years... )

[Johanp]

Chassis in now back from machining!

Made a quick testfit of front parts and it fits very nice.
Carbon from Bezerk is perfect!

Also, for us that are in the metric world...a 3.2mm pop rivet drill works great for clearing 1/8" (3.175mm) holes.

[Johanp]

Had a couple of hours free time yesterday.

Reassembled the gearbox with new diff washers and diff balls. Mounted the sliders using new inner halves in white plastic.

Also used the set of alu gearbox screws I had.

Continued assembly of the front end. Some light filing on the arms but that's it.

All new components for the spindles.

[scr8p]

I'm going to assume you've seen these before, but if not.....

https://www.rc10talk.com/viewtopic.php?t=22111&hilit=prototype

http://vintagelosi.com/Worlds_91_Buggies.html

[Johanp]

Thanks for the links!
Andy @ GP3D sent me a lot of pictures when I placed the order.
So I've seen most of them, but there are a couple that I had not seen.
Also reading the thread you linked, gives me even more motivation!
Let's hope I can find more time at the workbench soon.

[Johanp]

I'm in the process of finding the right stuff to put on the car.
I do have a set of the original gold/bronze hard anodized front shocks on my JRX-Pro. But they belong to that car so they will stay there. I chose to use a set of the darker shocks from one of my xxxt:s.

I just had to put some wheels on it to see what it will look like.

[Johanp]

Took the opportunity to paint up a body while I had the workshop heated.
Went for the Joel Johnson pattern but using my current colors.

I put Trinity stickers on. But then realized I don't have a period correct Trinity to use.
Might go for a slightly newer brushed Trinity Ex-tech or one of my Peak Performance motors.

[mikea96]

Very nice! I like that paint job as well. Is that an original pro se body?

[Johanp]

Very nice! I like that paint job as well.

Thanks!
I have a couple of variants using these colors.

My rear motor 22 "1.5" runner, the '91 Worlds and my runner XX (ongoing "cr" update, hence no front spindles and no rear end).

Is that an original pro se body?

It's a Team Bluegroove Pro SE body.
I get most of my bodys from TBG and they fit great.