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Building my first D3 Hardbody Group C car


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#1 DeanJ

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Posted 24 March 2026 - 12:57 AM

I'm jumping into the deep end... I started the build of my first brass chassis car to race in the D3 Hardbody GroupC / GTP class about 10 days ago.
It's a Tamiya Sauber Mercedes C9 kit that I'll use the body from. I haven't decided if I'll even paint it, I might just add some decals.

 

This pic I posted in another thread... the start of a concept, in my head.

IMG_7887b.jpg

 

Here's the progress... I used the lathe to make a custom aluminum spacer to go between the guide and the tongue, and I turned down a brass bushing to make a spacer on the axle.

 

IMG_7907b.jpg

IMG_7908.JPG

IMG_7912b.jpg

IMG_7931b.jpg

IMG_7944b.jpg

 

 


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#2 DeanJ

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Posted 24 March 2026 - 01:05 AM

I cut the side pods and I'm at a point where I need to decide how to continue... here's the question: do I put them with the square on the inside or the outside?

 

IMG_7956.JPG

 

and I think I need them to move a tiny bit, not be soldered to the main center part of the chassis, is that correct? I want the weight to be towards the outside of the chassis...

 

 

Also, do I make the rear wing and its support an integral part of the chassis or the body?


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Dean John

#3 Cap Henry

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Posted 24 March 2026 - 01:22 PM

Hey Dean, you might want to use a different guide tongue, that is really many to go on top of a coined tongue to be a stiffener, not to be used by itself, those are fairly soft.
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#4 team burrito

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Posted 24 March 2026 - 02:13 PM

Look me up if you're at Electric Dreams on April 25. I can give you some pointers on building your own chassis.


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#5 DeanJ

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Posted 24 March 2026 - 05:27 PM

No offense nor disrespect, guys.
 
But combined you both have been building cars longer than I've been alive, and can't for the life of you provide any input or answer my questions.

Thanks for the welcome.
And most wonder why the hobby has nearly evaporated.
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#6 olescratch

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Posted 24 March 2026 - 06:46 PM

Ouch!!
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#7 DeanJ

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Posted 24 March 2026 - 06:56 PM

A couple of the best builders the hobby has ever seen have told me about this forum. I come to absorb and learn, post my work and progress, and don't remotely get positive reinforcement on what I've done. Nor do I get constructive criticism at least.

Ouch, indeed.


Dean John

#8 Jay Guard

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Posted 24 March 2026 - 07:21 PM

Dean:

 

There are quite a few good ways to mount your side pans to allow a bit of motion. And to describe them properly would take quite a long detailed description. As we all know a picture is worth thousand words so your best bet to understand how to mount your side pans would be to check out this thread, Scratchbuilt chassis gallery right here on Slotblog.  There's a huge number of chassis' (126 pages to be exact) to view the various side pan mounting types.

 

As for answering your second question, 99% of the builders, and I would think especially with a hardbody car, you would want to make the rear wing part of the body. 

 

For your first scratchbuilt chassis I would say you've done pretty good with decent soldering skills, and it's obvious that you have some good machining skills as well, all a big help when building this kind of chassis.

 

Oh and BTW... Welcome to Slotblog!


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#9 DeanJ

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Posted 24 March 2026 - 08:27 PM

Thank you Jay for the insight!

 

Before I joined I lurked and looked through roughly 50 pages of the thread you mention - and it's a wealth of info.

 

The one take-away from all that's been posted in that thread, and what I read is... as a reader you don't know whether the car runs good or not - whether the setup and design is a good running chassis. It's just pictures of all kinds of builds.

 

As a beginner, how do I tell if something translates into a competitive car?


Dean John

#10 Cap Henry

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Posted 24 March 2026 - 08:33 PM

No offense nor disrespect, guys.
 
But combined you both have been building cars longer than I've been alive, and can't for the life of you provide any input or answer my questions.

Thanks for the welcome.
And most wonder why the hobby has nearly evaporated.


Hey Dean, Ive never built a chassis for any kind of hardbody other than drag cars, so thats why I didnt give any kind of answer, because I dont know whats right for that application. I also didnt say anything negative, I tried to advise you on something that could be an issue. Good luck.
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#11 Jay Guard

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Posted 24 March 2026 - 09:16 PM

Dean::

I would say that scratch built chassis' have evolved quite a bit since that thread was started.  Therefore I would suggest you check out some of the more recent chassis' in that thread as well as looking at some of the most recent race results threads, especially ones with hard bodies.  Although most of the info here will be for cars with thin vacuum formed Lexan bodies, I would think that many of the basic concepts would be the same.  Specifically, and especially true with hard body cars, I would say the lowest possible Center of Gravity should be one of the most important aspects of your design.


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#12 grooverunner

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Posted 24 March 2026 - 10:30 PM

Hi Dean,
Here is a direct link below to the latest D3 race. It has picture of the latest chassis that they are racing in group C class. Hopefully this helps,and welcome to the Blog. Ken

https://socald3.smug...CAR-Oct-18-2025
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#13 DeanJ

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Posted 25 March 2026 - 12:58 AM

Wow Ken, that's really helpful! It seems the chassis for the cars look mostly the same, with some minor differences.

 

I have a clear path forward after seeing all those! Thanks a million!


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#14 grooverunner

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Posted 25 March 2026 - 01:55 PM

Dean,
Did you notice on the chassis that are pan chassis there not a full pan chassis. They have a motor pod built-in that floats like a 1/32 slot.it car.and also they have a guide pod that floats for the guide flag.
That's been the combination for a few years now.
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#15 DeanJ

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Posted 25 March 2026 - 05:03 PM

Yes Ken thanks, those features you point out are nearly impossible to miss!
How did you all come to that being the standard?
Dean John

#16 grooverunner

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Posted 25 March 2026 - 05:45 PM

Dean,
You would have to ask Keith Tanaka about how the chassis evolved to what they are now. He has raced them from the beginning and does the D3 race reports. You can contact here by Pm.
Ken
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#17 DeanJ

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Posted 25 March 2026 - 07:17 PM

Dean,
You would have to ask Keith Tanaka about how the chassis evolved to what they are now. He has raced them from the beginning and does the D3 race reports. You can contact here by Pm.
Ken

Thanks! I'll pick his brain next time I see him at ED.

 

With the new found intel, I think I'm going to cut the motor pod off and make it float, as well as the guide plate.


Dean John

#18 grooverunner

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Posted 26 March 2026 - 12:13 AM

That's Great Dean.
Keep us updated on the build progress as it goes along.
Ken
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#19 Keith Tanaka

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Posted 26 March 2026 - 12:55 AM

Dean, I will be at Electric Dreams this Saturday (March 28th) to test some new Nascar loaner cars for the Enduro (April 25th). If you have any questions or would like to run in the enduro, let me know on Saturday.

 

Keith


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#20 vfr750

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Posted 26 March 2026 - 05:56 AM

Hi Dean, 

 

Have you seen these videos?

 

https://www.youtube....tonOdHJHM&t=87s

 

https://www.youtube....CLwMxwFU4&t=73s

 

Cheers,

 

John


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#21 DeanJ

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Posted 26 March 2026 - 09:24 PM

Dean, I will be at Electric Dreams this Saturday (March 28th) to test some new Nascar loaner cars for the Enduro (April 25th). If you have any questions or would like to run in the enduro, let me know on Saturday.

 

Keith

Thank you Keith, I'll be there Sunday for the event only. I'll catch up with you soon enough!


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#22 DeanJ

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Posted 26 March 2026 - 09:30 PM

Hi Dean, 

 

Have you seen these videos?

 

https://www.youtube....tonOdHJHM&t=87s

 

https://www.youtube....CLwMxwFU4&t=73s

 

Cheers,

 

John

Thanks John, yes I've seen them both. Originally I didn't want to copy anyone's work and wanted to make something that I come up with, using the basic principles. I was then reminded that in order to be competitive I'd likely have to build something that's already proven at being competitive!


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#23 DeanJ

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Posted 28 March 2026 - 11:58 PM

Update... I added the side pods that are structurally part of the center of the chassis. I also added a rear frame that I'll add some thin sheet to, as well as to the motor pod, and add a spring to it at the back. I'll then cut it free and hinge it to the center of the chassis. Then I'll work on making the front have some movement.

IMG_7977.JPG

IMG_7978.JPG

IMG_7979.JPG


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#24 grooverunner

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Posted 30 March 2026 - 01:23 PM

Dean,
Where do you buy the rear spur gear?
Thanks,Ken
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#25 DeanJ

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Posted 30 March 2026 - 01:45 PM

From Electric Dreams in LA
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