Reyes30

Hey guys new to RC game. I just bought the Rs4 Sport 3 about 3 weeks ago. So far I've just about done it all. I slapped some drift tires on it, took it through some dirt, smacked into fences etc. It Has taken quite a beating. It is my first RC car so i don't have much to compare to, but its freaking awesome. No dogbone issues whatsoever.
However I would like to try doing a Rally conversion. Any one have any Experience in this? Thinking longer shocks? wheels and tires? Help pls. LOL

Mr P!nk

iTrader: (1)

That is actually the exact reason I bought the Sport 3 was to make it a rally car, so I have a little insight for you.
I started with some shocks and springs from the old HPI RS4 Rally (part # A721) they are kind of difficult to find though, and most people on ebay try to sell them for unbelievable prices. Hpi has a plastic shock of the same size but I'm not sure what that part number is. The shocks are 50-66mm so if you can find something near that range in length then you could probably make them work.
I would maybe take a look at what Tamiya has for shocks, they have a few purpose built rally cars that might have slightly longer shocks for rallying.

I put the HPI shocks on without any modifications to anything else at first:


You'll get about 13mm of ride height with those shocks:


The only problem is you don't have much if any droop left in the front (maybe 1-2mm if you're lucky), that's about the max down travel that the front suspension allows in stock form. The rear is fine however, plenty more down travel.
This may be sufficient for most people and I guess my suggestion would be to try it out and see if it works for you before you start modifying stuff.


I decided I wanted to try and get more travel out of the front though, so step one was to remove the A-arms:


I know this is kind of a bad picture but the idea is to dremel out the inner corners where the C-hub would hit the A-arm. I know my picture shows some dremel marks on the middle section, those aren't necessary, that was more me getting careless with my dremel.
If you leave the C-hubs attached via the hinge pin while you are grinding away material on the A-arm then you can just swing the C-hub back into place and keep checking the fit until you get it sitting deeper into the A-arm.
I will say it doesn't take much to get the C-hub sitting in there lower, a little does go a long ways.


Both sides done, again, it didn't take much. Unfortunately I didn't take a side by side comparison picture to show just how much it actually moved the C-hub.


You will also need to remove some material off of the chassis for the A-arms to drop lower:


I got it all back together and ride height and droop were much improved, unfortunately I noticed that the steering links were now catching on the edge of the chassis at full droop, so more material needed to be removed from the chassis on both sides:


My ride height is sitting at 16mm currently:


And now the front and rear reach full down travel at about 22mm.
Whereas the stock front could only reach about 14-15mm, so I'd say it's a good improvement.


I did measure the rally tires I'm planning to run and they are a few mm's taller than these tires I currently have on here, so that should give me a bit more ride height as well.

Hope this helps a little. The only difficult part is going to be finding some shocks to use.

Reyes30

Thanks man this is exactly what i was looking for. Your car is looking great! Good work.
Im gonna hit the hobby shop tomorrow to look for some shocks.
Just a couple questions first. Do you have a part number for those adjustable upper arms/Tie rod ends? or universal? and what tires do you plan on using? I wanted to go with a bigger set but im afraid it wont clear the front bumper when i turn? Im really new to this so I really appreciate the help!! Thanks

Mr P!nk

iTrader: (1)

I just made the upper links from HPI #93317 (4-40 x 34mm), and the steering links from HPI #93312 (4-40 x 24mm). you can add whatever rod ends you want to those tierods. I used RPM 4-40 rod ends, but I had to swap out all the ball studs on the chassis for smaller ones. I had a bunch laying around, but if you don't then you would need those buy those as well. I'm sure there are some rod ends that will work with the stock ballstuds, but I just used what I had.

I will be using either HPI Pirelli T Rally tires, or Tamiya Rally Blocks. They are both for 26mm wheels. You could go with something a little larger but then you run the risk of what you already stated, plus anything that's not for a 1/10 touring car just looks a bit strange and out of proportion.

Good luck with your build, share pictures as you make changes.

SagadSetup

iTrader: (38)

http://s15.postimg.org/iugk5k8gr/G_05.jpg

Mr. P!nk, how about relocating the ball connector on the top of the knuckle? It's just a thought...

Maybe, just maybe that will help so that the steering links will not catch.

My only worry is it might mess with the steering geometry.


Looking good so far. Please post pics of the whole chassis. I am curious to see how it looks from afar.

Regards!

Mr P!nk

iTrader: (1)

That is a possibility, you could mount the steering link to the top side of the knuckle, if you could shim up the the ballstud on the steering rack the same amount then the geometry would remain the same.

I might have to look into this more, thanks for the tip. Even though I already took the dremel to my chassis, lol.

SagadSetup

iTrader: (38)

Thank you for sharing your mods Mr. P!nk.

Now in terms of ride height. Would it increase if you add 1mm or 2mm spacers under the suspension blocks? Is that a feasible solution if increase in ride height is desired?

Again, roll center will be altered if that is done.

CarlosRS4

I just purchased mine Friday and after running it for 5 min the dog bone came out. Same issue here. Not enough o rings in the cups to keep it from popping out. Also had to trim the body before I could even use it. I see the link you guys posted about the upgraded longer dog bones. How are they holding up? Thanks.

ghostgr

My car will be back from hpi tuesday. I shall let yall know what if anything has been done. I went to my local hobby shop I got the car from and all the flux models have the dog bone issue. Some were hit or miss with the body issue. I did look at the regular sport 3 and the drift version. Neither had the problems we are. So it appears that this version really just fell on it's face. My hobby store informed me that all the option parts for this should be out by mid august.

SagadSetup

iTrader: (38)

This is what I was thinking Mr. Pink. Add maybe 1mm to 2mm spacers to get more droop.

Do you think that'll work?

CarlosRS4

I called HPI customer service department this morning and mentioned to them the issues I'm having with the Porsche. They are sending me 8 o-rings and a new axle because when the dog bone came out it damaged the cup that holds it in place. Took about 30 min on hold BUT it was worth the wait

I asked about the upgraded options but they wont be available until August 31st

SagadSetup

iTrader: (38)

With all the complaints coming in, HPI will resolve these issues.

Goodluck!

Cudacharger

iTrader: (4)

Thanks for the update CarlosRS4 I'm sure these dogbone issues are going to hold up the second batch release of cars to coincide with the optional upgrades released August 31st. I'm going to upgrade everything on the car that hpi offers when mine arrives this week so I guess it's going on the shelf until the factory parts become available since I want to keep the car all HPI for personal reasons.

With that said I might pickup a Sprint 2 Falken Porsche to tide me over.

Anyone own the (#108220 Falken Porsche Sprint 2) have any dogbone issues out of the box like the new RS4 Sport 3 Falken?

racinmason

iTrader: (9)

I hope everyone with the dog bone issues get resolved. I thought hpi was supposed to be better quality. I'm anxious to see how they fix the problem.

I did receive my spec r universals today and they fit perfectly. No binding and it feels pretty smooth.

ghostgr

Got my car back. They didn't fix the axles. All the did was trim the body properly. Rather disappointed.