Create a Porsche 934 replica in 4 steps

For all things R/C, post '90s to today.

Moderators: scr8p, klavy69

User avatar
XLR8
Approved Member
Posts: 2967
Joined: Sun Feb 19, 2017 3:46 am
Location: north/central Alabama
Has thanked: 1188 times
Been thanked: 866 times

Re: Create a Porsche 934 replica in 4 steps

Post by XLR8 »

The new motor is very heavy and changed the car's balance (understeer on corner exit) but I was able to bring it back a little closer to neutral by decreasing rear toe angle from 2 to 1 degree. I like the handling with the new motor but now I'm searching for a bit more speed. After 30 minutes, the motor was only slightly warm so I'm gearing up from 7.28:1 to 6.15:1 FDR.

I also noticed a wear pattern on the rear tires that suggests that it needs more camber angle so I've fitted 1 shim (a washer, actually) to each lower radius rod. The lengthened rod kicks the bottom of the tire out by about 1-1/2 degrees.

I'm back to the tennis courts in the morning. The weather here is shaping up nicely so hopefully I can run the car each day this week.

Big smiles from me; the car responds well to tuning and is tons of fun to drive. :D
Doug

User avatar
MarkyDents
Approved Member
Posts: 1021
Joined: Sun Jan 10, 2021 11:52 am
Location: Staten Island, N.Y.
Has thanked: 1347 times
Been thanked: 509 times

Re: Create a Porsche 934 replica in 4 steps

Post by MarkyDents »

Wow what a sharp looking piece you’ve put together here, very very nicely done 8)
Who do you race for ?
Me……. I race for me.
That’s impossible, I was told you need a sponsor to race.
Hey Cru ! Go balls out 8)

User avatar
juicedcoupe
Super Member
Posts: 2976
Joined: Sun Aug 16, 2020 4:05 pm
Location: Pascagoula, MS
Has thanked: 229 times
Been thanked: 1742 times

Re: Create a Porsche 934 replica in 4 steps

Post by juicedcoupe »

If you like the extra torque and weight of a 550, I have one of these in my Torment.

https://www.integy.com/st_prod.html?p_prodid=39764&p_catid=518&gclid=Cj0KCQjw6cKiBhD5ARIsAKXUdyaVLcm8dBJ6zBlbcY2XA2To2U_ZYrq2iWr5-2KKN6nGwWBwtO3h0fQaApXCEALw_wcB

It has no problem putting a heavy SC truck on it's bumper (or roof).

I bought mine on Amazon but availability is hit and miss.
Always looking for new and interesting ways to waste money.

User avatar
XLR8
Approved Member
Posts: 2967
Joined: Sun Feb 19, 2017 3:46 am
Location: north/central Alabama
Has thanked: 1188 times
Been thanked: 866 times

Re: Create a Porsche 934 replica in 4 steps

Post by XLR8 »

I’m using 4000mah batteries and after a 30 - 35 minute run, the motor is still only slightly warm. The taller pinion gear installed yesterday has yielded an increase in speed but I think there’s more left in that motor - maybe much more. It just needs more gear.

I’ve been running the largest 32dp pinion I have (22t) with a 52t spur for a 6.15:1 FDR. After rummaging through some boxes, I found a 38t 48dp pinion so I’ve paired that with a 78t spur for a 5.34:1 FDR.
P1010101.JPG

FWIW, that is the largest motor pinion I've ever held in my hands. :shock:
Anyway, I’ll run the car again in the morning. Fortunately, the tennis courts are empty on weekday mornings.
It’s very windy again today and that makes it difficult to tune the car. Tomorrow’s forecast is for sunny skies and calm.
Doug

User avatar
XLR8
Approved Member
Posts: 2967
Joined: Sun Feb 19, 2017 3:46 am
Location: north/central Alabama
Has thanked: 1188 times
Been thanked: 866 times

Re: Create a Porsche 934 replica in 4 steps

Post by XLR8 »

The tennis courts were very dusty and slippy - probably a result of the high winds over the past several days. Anyway, the car was faster but much harder to drive on that dusty surface.

It handled the curves fine but the tires would suddenly break loose in a straight section -- the tire spin was completely random.
I had been lucky so far -- not hitting anything -- but eventually the car spun and I was unable to stop before it backed into one of the support posts for the nets.
A wheel is broken, the motor plate is bent and even the chassis plate is bent. :( I’ll order another set of wheels and straighten the bent plates.
P1010102.JPG
P1010105.JPG
P1010108.JPG
Fortunately, the printed trailing arm has survived the impact. MFJ nylon is very tough.

The bunnies are okay as well. :wink:
im okay.jpg
Doug

User avatar
Frankentruck
Super Member
Posts: 2566
Joined: Fri Feb 19, 2021 9:59 am
Location: Texas, USA
Has thanked: 1574 times
Been thanked: 1739 times

Re: Create a Porsche 934 replica in 4 steps

Post by Frankentruck »

Sounds like it drives like a vintage 911 should, on the hairy edge of out of control!
Frankensteined RC10T3 / Franky Jr RC10GT-e (x2) / A+ stamp / Toy Story RC / Graphite replica / B1.5 BFG 5LTi / Clonewald / Hyper Hornet

"I love the effort, but it sure looks like you took the long way around to a tub again"

User avatar
XLR8
Approved Member
Posts: 2967
Joined: Sun Feb 19, 2017 3:46 am
Location: north/central Alabama
Has thanked: 1188 times
Been thanked: 866 times

Re: Create a Porsche 934 replica in 4 steps

Post by XLR8 »

Frankentruck wrote: Sat May 06, 2023 5:14 pm Sounds like it drives like a vintage 911 should, on the hairy edge of out of control!
Haha… I had the same thought. Although I’ve never driven an actual Porsche, I can imagine how much fun that would be.

I live about an hour from Barber Motorsports Park near Birmingham Alabama. By the way, if you’re ever in the area, you owe it to yourself to visit the park with its world class museum -- you won’t be disappointed. Anyway, Barber hosts the Porsche Track Experience driving school. It’s not cheap (a 2-day class starts at $3,900) but the experience of driving a fast Porsche around that epic track is something I’d never forget. :D

https://www.porschedriving.com/track-experience
Porsche Driving Experience.JPG
Doug

User avatar
XLR8
Approved Member
Posts: 2967
Joined: Sun Feb 19, 2017 3:46 am
Location: north/central Alabama
Has thanked: 1188 times
Been thanked: 866 times

Re: Create a Porsche 934 replica in 4 steps

Post by XLR8 »

The bent plates have been straightened, the wheels re-aligned and it's ready to go again.

I can run those heavy aluminum wheels until the replacement plastic Tamiya wheels arrive.
P1010113.JPG
P1010115.JPG
Bugs is happy. :D
P1010117.JPG
Doug

Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

  • Similar Topics
    Replies
    Views
    Last post

Return to “21st Century Modern”

Who is online

Users browsing this forum: No registered users and 6 guests