cbp27's HPI Nitro RS4 3 Evo+ Rally Conversion
 

Well after having two of these nitro cars in the past and having an electric car everytime in between, I've decided to get back into nitro again.

My last car was a HPI RS4 Rally, which was electric, so this time I'm going to convert my nitro car into a rally car. I found some help from an old HPI forum thread and another person who has done this conversion before.

My ultimate goal is to have something like this: http://www.youtube.com/watch?v=hEK7POxpVeE

The old Group B Audi Sport Quattro S1! :mrgreen: Tamiya made the body a long time ago, but it's virtually extinct now. Luckily I found a link to someone who makes a reproduction version.

If you're new to the HPI Nitro RS4 platform and/or rallying, hopefully this will keep you mildly interested.

Here's my last nitro RS4. Pretty much stock except it had a Tsais rear exhaust. It literally had about 1/8" of ground clearance. (Would get stuck on a single blade of grass lol)
http://i767.photobucket.com/albums/x...y/IMG_2212.jpg
http://i767.photobucket.com/albums/x...y/IMG_2214.jpg


Here's my new RS4. I just got it on Friday and worked on it today. I replaced the shock towers with larger ones from the HPI Super Nitro Rally and used the front HPI MT2 shocks all around. That added about 3/4" more clearance. I know it might effect the center of gravity, but I'm excited to try it anyway.

http://i767.photobucket.com/albums/x...y/IMG_3395.jpg
http://i767.photobucket.com/albums/x...y/IMG_3396.jpg
http://i767.photobucket.com/albums/x...y/IMG_3399.jpg
http://i767.photobucket.com/albums/x...y/IMG_3400.jpg

I replaced the stock Roto-Start system with a pullstarter for simplicity.
http://i767.photobucket.com/albums/x...y/IMG_3402.jpg

Got this fancy spur gear cover from the HPI MT2 as well. Hopefully the flames will get rubbed off soon.
http://i767.photobucket.com/albums/x...y/IMG_3410.jpg

Leftovers...
http://i767.photobucket.com/albums/x...y/IMG_3415.jpg

I'm worried about the dogbones falling out since they are at such severe angles, so I'm replacing them with MIP CVDs. I'm also planning on ditching the huge shocks for smaller ones. You'll notice the front shock tower is very high...so high it would prevent me from placing a body on the car. I can mount the smaller shocks lower and trim the top of the tower, leaving enough clearance for a body to fit.

My last RS4 (pictured at the very top) used a FM radio system. I learned the hard way why they suck. I'm using my Spektrum DX3E this time.
I was driving it in the parking lot with Chris (Gimp) and lost ALL radio control, while it was at FULL throttle! It magically went towards the only large object in the parking lot and....PING!!! lol We were both in disbelief but couldn't stop laughing

http://i767.photobucket.com/albums/x...y/IMG_0545.jpg
http://i767.photobucket.com/albums/x...y/IMG_0549.jpg

Gimp got me out.
http://i767.photobucket.com/albums/x...y/IMG_0560.jpg
http://i767.photobucket.com/albums/x...y/IMG_0563.jpg

Surprisingly these little cars are incredibly durable and it started right up and I drove it off with the front half gone lol
And after replacing some parts up front you couldn't tell this even happened. The body was salvageable too. The shots at the very top here were taken after this crash.
Like this:
http://i767.photobucket.com/albums/x...y/IMG_2204.jpg


Anyway, hopefully I'll be getting a body soon and then I can post some real progress.
Thanks for looking!"thumbsup"

OUCH!!!

something similar happened to one of my Tamiya TT-01's last year, i was playing in a huge parking lot and lost control (fm radio) it went in the street and was run over......the front half was totally trashed......


so now i run all 2.4 radios and play on the other side on the parking lot


What are you gonna run for rally tires?

Yeah losing radio control isn't fun. Never going to use am/fm radios again! "thumbsup"

Here's a list of upgrades I hope to eventually get:

MIP CVDs for front/rear
Longer differential cups front/rear
Slightly shorter shocks (allows front shock tower to be trimmed for body to fit)
HPI MT slipper clutch (replaces 2nd gear)
HPI Pirelli rally tires
HPI 5 spoke white wheels
Audi Sport Quattro S1 body (hopefully)
Tsais Nitro Devil rear exhaust

Not sure how soon I'll be able to get these parts so the next update might be a while.

Subscribed..I will be watching this closely, as I am trying to do the same...I REALLY want to build a nitro version of the Tamiya Lancia Delta Integrale, but I'd have to shorten the wheelbase of the RS4 chassis, and I can't figure out how to do it without compromising strength...

BTW: all your pics are now red x's...

Have you thought about using CC-01 shocks? At 80mm they might be the perfect length...

I'm glad this is helping someone haha. Tamiya's 51501 Lancia Delta body has a 257mm wheelbase, which is the same as the RS4 chassis so you should be able to use that body withouth modification to the chassis.
http://www3.towerhobbies.com/cgi-bin...?&I=LXYNH4&P=7

I got the longer diff cups, CVD's, tires, 2 wheels, and integy 78mm shocks (as a test). They're all installed but I have no pictures to post yet. My other two wheels, shocks, and body should arrive within the next week or so. I haven't even had a chance to drive this car at all so I can't wait to have it running soon. :mrgreen:

Thanks for the headsup. Photobucket's site is under maintenance right now so that's why my pictures aren't showing up. I hope that's fixed soon. Stay tuned for updates!

Cool I'm doing a similar conversion at the moment. with the difference being mine will be Electric. I have lots of super rally parts too and your front shock tower idea seems like a good one. What did you end up using as a rear tower? Also let me know what shocks you will end up using. I'm stuck at that right now, as well as how to mount the body without using that giant bumper that usually holds the bodypost for the front. Cant wait for Photobucket to come back up.

I just found some shocks that may work for us. HPI 1/18 scale brahma front and or rear shocks. Rear is 63mm long and front is 57mm long. I'll measure tonight.

Are you turning a Nitro RS4 into electric or are you starting with an electric RS4 platform? I got HPI A373 parts tree, and I used both shock towers and front bumper for mine. You can still use the original front bumper and only do the front shock tower. I'm trying Integy MSR11 78mm shocks. I know Integy isn't the greatest, but they were cheaper so hopefully they will hold up. I was originally going to use these: http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_498wt_1002 But I was afraid of them being a little too short. Let me know if you need any help.

Converting from Nitro to electric. I'm using CKRC's HPI MT2 SC conversion parts. Motor mount is like $45 or so. then you just have to figure out a battery holder and mount the steering servo to the chassis and rn a brace acrosss the top. See I don want to use the original RS4 front bumper. That thing is like a giant snowplow. Cant rally with that

Nitro to electric will be interesting. The bumper that comes with the Nitro RS4 is pretty low. I acutally did what HPI recommended (8 years ago lol). They cut the front end of the chassis off to mount the Super Nitro Rally front bumper, which curves up giving more clearance. However, with the springs mounted lower, you can't properly use the bumper brace because it gets in the way of the shocks. This link should help show the bumper: http://www.hpiracing.com/rcforum2/sh...threadid=62303
I'll try to get some new photos up this weekend to explain more if you need it. I wish Photobucket was working.

That's a cool Idea. I think I'l try the SNR front skid mod or use the MT2 skid whick is the same and that shock tower and other stuff from the SNR. I think I'll figure something out as far as the brace that holds the body mount to the shock tower. Great Ideas dude. Yeah I wish Photobucket was working that way i could get a few more Ideas. I;ll post some pics of mine tonight on Scale and then transfer them over here.

Thanks! Good luck on your build. Let me know if you need any help "thumbsup"


Well since my Photobucket account still isn't working I started uploading pictures on here. I've made some progress but I can't drive it until my second set of wheels shows up.

Installed:
HPI MIP CVD's front and rear
HPI Diff Cups
Integy MSR11 Shocks front and rear (I know it's a crappy brand, but they fit so I hope they hold)
HPI 5 Spoke White Wheels
HPI Pirelli Tires
HPI MT Slipper Clutch (18T pinion and 47T spur gears)

http://www.rccrawler.com/forum/pictu...ictureid=20812

Shocks are the perfect length. You can see the new silver diff cups and CVD's also.
http://www.rccrawler.com/forum/pictu...ictureid=20807

I had to use these spacers on the front shocks to keep them from rubbing the tower.
http://www.rccrawler.com/forum/pictu...ictureid=20808

Had to cut the front of the bumper brace to clear the shocks. Hope it doesn't let the bumper snap off in a crash!
http://www.rccrawler.com/forum/pictu...ictureid=20809

CVD's up front.
http://www.rccrawler.com/forum/pictu...ictureid=20810

These wheels were the closest match to the Audi S1's.
http://www.rccrawler.com/forum/pictu...ictureid=20811


Hopefully I'll get the other wheels soon so I can start driving it. The Audi S1 body was supposedly shipped on the 13th but has an estimated delivery of May 2nd through 13th. I might have to use the stock Nissan body for now lol

I can't seem to find anyone that still has hpi a374 in stock. Everybody shows it as disco'ed. Also it looks like you have very little suspension travel. I may just buy some super short dubro body mounts and flip the plates that they mount to if I can't find that a374 part. Need some more of those anyways.

Why are you looking for A374? Do you mean A373? That's the parts tree with the shock towers and bumper.

I needed shorter shocks in the front for the body to fit. I still need to test them out though.

Naw I have plenty of the A373's. I'm in need of the body mounts/posts or whatever you want to call them. they are part of the A374 batch. I have 2 Super nitro Rallies and have just recently bought some WRX corolla hatch bodies that I need long body posts for. I used exactly those parts that that link you posted had in it. my rear will sit 1/4 inch higher than the front but that's ok with me. http://www.gravesrc.com/v/vspfiles/photos/HPIA374-2.jpg them long body posts is what i'm in need of.


My build thread: http://www.rccrawler.com/forum/non-crawler-rcs/312857-my-rs4-nitro-road-electric-rally-drift-conversion.html

You should be able to use this: HPI 85032


Great news! My wheels finally arrived and even the body! :mrgreen: The body wasn't supposed to arrive until some time in May lol

http://www.rccrawler.com/forum/pictu...ictureid=20940
http://www.rccrawler.com/forum/pictu...ictureid=20941

The wheelbase is a perfect match, but I might have to enlarge the wheel arches for some clearance. Also the front body posts are extremely far forward, but it will look like hood pins so maybe it won't be so bad. And another surprise is that the body has plently of clearance above the front shock tower (almost 1.0"!). So when the Integy shocks crap out I can replace them with the HPI shocks. I might not have enough time to work on the body this weekend and next week is study time for finals so it might not be until May when I post an update.

Only had enough spare time to trim the body and mount it. I'm still unsure of what paint/sponsorship theme I want to go for. I'm still searching for the original decals but they're almost impossible to find. If anyone has the Tamiya/Carson/Chevron Audi Quattro S1 (Pikes Peak too) decals, whether original, reproduction, or even just a good picture, please let me know "thumbsup"
Otherwise, if I can't find any decals I might try doing a modern day interpretation with a new livery.
Here are some quick shots with the body mounted.
Still need to do some final trimming.

http://www.rccrawler.com/forum/pictu...ictureid=21498

At first I thought the body posts weren't going to look nice up front, but then I realized they look like the real hood pins!
http://www.rccrawler.com/forum/pictu...ictureid=21497

http://www.rccrawler.com/forum/pictu...ictureid=21496

Lookin gewd "thumbsup"

lookin good, i say paint it like a replica and beat it like the real 1:1 haha

That body Looks killer