Yeah, that's why I have the hardest swaybar on the front and the softest one on the rear. The rear doesn't need a swaybar to make it behave, but I wanted significantly less body-roll despite using soft long-travel shocks, and the only way to reduce body-roll as much as I wanted without massive understeer was to have swaybars on both ends of the car instead of just the front.

You are very right. It started happening. I started seeing some binding in some suspension arms. My streets are hella dirty. Black soot can be blown off the car ever time I drive it. I guess super tight is for carpet and indoor tracks. Or someone with a meticulous cleaning regime.

Taking apart the suspension on this car is a pain. So maybe I live with .2mm of play 😄

I'll take out those shims when my diff fluid arrives. Or Maybe I buy myself an air compressor?

So I got my diff fluid and rebuilt the front end with 60k. It is now plenty sticky up front, and slows down the diff by ~70%. It's to the point where if you spin the diff, it spins freely, but sometimes rotates the motor into the next magnet pole.

Driving with this ultra dense diff fluid is different. It definitely pulls the car where you point the tires, but sometimes (with my dusty streets) a little too much fish tailing. I learned to tone down my turns so that I'd keep all 4 wheels under traction. The front mount motor and 4wd really like turns under smooth power. I guess you could say that with all 4wd cars really. 😄


Instead up pulling out shims, I just put a drop of 3-in-1 oil on the hinge pivot points. It works like magic. This is what I usually do with my bicycle parts. Yeah it attracts dirt, but only on the surface and can be easily wiped clean. The suspension moves freely, and should remain so even when a little dirty.

I had been toying with the idea of buying a compressor to clean my workbench and car after every run. I even went to the Home Depot and had the thing in hand. Lucky my wife was there with me and said to reconsider, or get a smaller one. I came home a little disappointed, but then remembered that my friend said I could use the shop vacum output blower. Man, does it blow. It's a little loud yeah, but it gets the job done quite well. My car has never been so clean. I'd vacum, but sometimes I have little screws everywhere. Anyway, it works well. No more buying those throw away air canisters.

Suspension, now I don't know if you all agree, but this car drives pretty well on road with the suspension jacked up to rally height. I put the street tires on (24mm USGT Ride radials) with the CVA dampers with the long ends. It's great! I might just keep this car riding high. It pulls turns just as well as when the suspension is dropped.

The tires and wheels I am trying now are $25-30 from TQ Racing. I would say they aren't as nice as HPIs D-compound x-patterns but they are less expensive. I will see how long they last.

Does anyone else drive with 24mm wide tires? I have yet to find an amazing set of tarmac/rally tires that will last. The quest continues.

I am still loving this chassis.

Driving with the tail swinging out is great fun, though. Just like a real rally car showing off for the spectators. The oversteer is very controllable on this car.

If you keep oiling the suspension shims on a regular basis, the oil working its way out from between the shims should keep the shims clean. You have to wipe the excess oil away after pretty much every run though. I'm too lazy to do that, so I live with a little slop instead.

The long dampers have the same ride height as the stock dampers with the long lower eyelets attached. You have to buy different shock towers to use the long dampers, but the car handles cracks and bumps SO well because the wheels have the full range of travel instead of having the shocks bottom-out while the chassis is still well above the ground.

I like HPI V-Groove Pro Compound tires for on-road use. I have them on multiple cars now. HPI Super Radials are also pretty good, but not as soft and grippy as the V-Grooves; the Super Radials don't really start to grip well until you wear the shine off them and get them warm, whereas the V-Grooves are good to go immediately. And for rally use I love HPI's Pirelli rally tires in S-compound. I use D-compound on my RS4 rally car because it's so much heavier, but even with the harder rubber, the Pirelli tread has so much mechanical grip that they still work well as long as the pavement isn't super-smooth. Those are all 26mm though.

Wow. I finally found an empty parking lot (all be it across town) that has perfectly smooth black tarmac. The security guard kicked me out after 10 mins but.... During that time it was ear to ear grins. This cars handling is awesome. I was power sliding perfect 90 degrees turns with no spinning out. Dust was getting kicked up like dukes of hazard style. I am running a 12 degree turbo, which isn't peak, but i am balancing heat vs top speed, it was pretty fast. Plenty fun. 4wd handling is great, I am ready to race Forget tire sauce, getting sideways is very realistic and entertaining.

I also picked up a 190mm HPI BMW M3 GT body for $25 (way cheaper than online with shipping) at a local hobby shop which has hundreds of bodies! I think the owner just bought in bulk and doesn't sell them fast enough. Looks like some of them have been there since the late 90s. One minor thing, I found out though, that the real M3 GT touring cars are actually only RWD, but whatever.

GT touring car and rally car all in one chassis. Yes!

Oh yeah, I was on eBay, and saw a bunch of China sellers selling HPI pirelli knock offs for 12$ with shipping. Rims, foams and tires. 4 pieces. They are of unknown compound but whatevers. I might try. All this stuff comes from China anyway. The ride tires/rims I have are pretty good. But look kind of small. I wonder what 31mm tires all around would be like?

I'm just testing one of these Pirelli knock-offs made by Austar, together with couple other tires made by the same brand (there's a spanish site listing them, but I can't post links). As far as I can tell, they are not bad. The "Pirelli" tire is in fact very decent on wet tarmac, plus my source has red and blue tires as well (which looks kind of cool, especially red ones combined with GT86 Gazoo body).

I also have [Austar ATTACK + ELEGANCE G, which seem to work well on dry tarmac (better than "Pirelli"). I'm going to buy couple more Austars to see what they can do (my price is $14 per 4 complete wheels). I will report back what I will find.

I can compare them to HPI X-Patterns, Fastrax Rally Blocks, and Ripmax Rally Blocks. I'm thinking about buying one set of HPI Pirelli S compound for reference, but people who race XV-01s around me say that it doesn't worth the money. Unfortunately I can't buy HPI V-Groove Pro or Super Radials at the moment, as the local HPI distributor is not selling them.

Does anyone know what tires are in the very first picture of this thread? Page 1. First post? They look like some sort of realistic radial.

Bodies:
Today I masked off my new HPI BMW M3 GT body. I messed up making holes, 10mm off, and had to redo 4 holes. Ugh. Compared to the Tamiya body, this one is a little wider, and those 24mm wide wheels i have, are looking pretty inset. Color scheme, I am thinking a 2 tone metallic blue with white hood, roof and trunk panels with black stripes that follow the hood,roof, and trunk contours. I don't know what it will turn out like, but will probably start painting tomorrow. More to come.

I don't know what those exact tires are, but HPI Super Radials are comparable.

When making body-post holes, I find it helpful to balance the body on the posts, figure out how much to cut off the posts to get the body to sit level (not at final height, just level), make the necessary cuts on the body posts, and THEN center the body on the chassis and mark the hole locations. I screwed up a couple bodies thinking that the hole locations would be "close enough" if the body wasn't sitting level above the chassis; I was wrong.

Yes, level is the key. The Tamiya hatchback body came with dimples, the HPI sedan body was a guessing game. I realized after what I should have done was set the body beside the car with the tires in the wheel wells, then draw square sight lines onto the lexan. Fore/aft holes would have been dead on.

Side to side is much easier after that, and can pretty much be eye balled by setting the body directly on top of the posts using the fore aft lines as guides. X marks the spot.

My masking job was pretty bad in some places. I got some spray through. always burnish edges after taking off you layers of masking!!! Since this body already has 'extra' holes, and a less than perfect, albeit satisfactory paint job, it will be deemed the beater. Decals go on tonight.

Even the dimples are never exactly right. The body posts are never perfectly vertical, and the chassis is never perfectly square, so the dimples are at best a close approximation of the correct spot to cut the body post holes.

I don't do complicated paint schemes, but occasionally I've gotten a bit of overspray onto a window surface. I figured out I could use a Q-Tip soaked with Goof Off to remove the overspray, but I have exactly one swipe to remove as much as possible, because a second swipe will smear the Lexan.

HPI BMW M3 GT, once removed the overstay film, it look a lot better. Decals help cover up some of the mistakes.

Shiny! Needs wider-offset wheels in the back, though. Looks like it might need +6mm in the rear, and maybe +3mm in the front.

Hey folks. I have a NIB minus the outer wrapping XV01T (all parts are still wrapped). Everything included, looking for $150. PM me if you're interested.

Definitely. Wider offset with this body is needed. I'd probably go with 6mm all around so I can get hella flush or poke happening. Because race car.

Poke adds drag though.