pirespreto.com :: HPI RS4 Pro 2

The RS4 Pro 2, the Integra body and the Multiplex Profi Car 403 that must be the best pistol grip radio I've ever seen (with the exception of model 707...)

What can I say? I knew it ! I knew that I would not stop just with the rally car. After going to a track and trying an Associated TC3, a touring car was the obvious next step.
But what car? HPI, Associated, Losi Yokomo etc, etc were the possible choices. However I had lots of spares for the rally car. Tires, wheels, sway bars, ball bearings differentials, which made my life easy in choosing a touring car - The RS4 Pro 2.

As usual perfect assembly guide, and a record time of 3 hours to assemble. Of course you'll need an electric screw driver, a very sharp Xacto knife and a very organized working bench.

The body took 3 to 4 hours to paint and a couple more to apply decals. It was painted with my Badger 150 and Tamiya paints. It is a very simple painting scheme but very effective and it turned some heads.

The Lexus IS200 is now ready for some scratches. At first I thought I had made a terrible mistake by painting it like this, but now I got used to it and I like it. What do you think? Go to the HPI gallery and you can see it there

The Lexus IS200 body was "created" in one night. I just has this idea of painting a body with lots of colors...
After removing the masking I was not very pleased with the results. I thought it was terrible. A result of some sort of brain malfunction. On the weekend I took the body to the track and everybody was saying that the body was awesome. I sent a couple of pictures to Frank McKinney (Web Master of the HPI site) and he too thinks that the body is fabulous. I have it on the HPI Gallery!!!. Talk about misjudging your work...

After assembling the car I could find some very noticeable differences between the Rally version and this chassis. The suspension geometry is quite different and very tunable so that we can get the most of the car.

After getting used to the handling of the car I started to make 3 or 4 perfect laps between crashes. At the end of the day I was doing 14 laps between 29.5 and 31 secs. Not bad, if we consider that the motor was a conservative Orion 12x3 and the car was completely stock, with the exception of the tires that were X Pattern tires from HPI.

The Internet has lot's of advantages, but if you are like me it can be a problem. I went to the HPI site and found springs, options parts and lot's of neat gadgets that can go well on this car. I got the most of them, with the exception of those anodized aluminum stuff.

If you are an aluminum freak, prepare to spend more in alu parts than you spend on the car. Their utility or advantage is in most cases perfectly marginal, if you take out the need to impress your friends (and especially your enemies).

I tried to tune the suspension with stiffer springs and different shock oils, and now the car handles much better. However I changed the spur to a smaller one and the top speed increased dramatically, but the braking is very sudden and uncontrolled.
I should have followed that lesson that says - tune one thing at a time, so that you know were the changes come from...

After my experiences in 1/12 scale two days before, I went to the track with my RS4 Pro 2 fitted with 24 mm HPI belted slicks 20R (4750 - Racing Slick Belted Tire 24mm (20R - Cold Weather)). These tires have an incredible grip and I was lapping really fast. This track is VERY WIDE when compared with the carpet track for 1/12 :-). No mistakes and no crashes!
After two packs one of the front tires was showing the insert... I had to change tires and hope to drive that well again.
I had a set of 26mm Pro Compound Belted slicks (4415 - Pro Belted Slick Tire) that I had put aside because I thought they were inadequate for the track.

You know what? It doesn't matter that much. The theory that the driver is 80% is real. I could lap on the same time with these tires. The guys that were running there had HPI 20R and 23R and they could not catch me. Not even one crash. 1/12 scale is in fact an incredible driving school.

Today the car was PERFECT! I changed the D4 9x2 for an Orion Chrome Touring 11x3. The D4 is not the same as it used to be. I trued the comm and used 4380 brushes but the run times and rpm suffered a lot. Additionally the tabs where the wires are soldered tend to break. I decided to put another motor.

I almost forgot! I changed all my packs from stick to saddle and this also made a huge difference in balancing the car. The rear just doesn't go away as it used to. Am I getting really paranoid with details or is just my driving skills improving. I can't tell. I'm changing too many things at once...

The spur/pinion is now 115/38 (Robinson Racing spur and Robinson Racing purple pinion). I spent a lot of time tuning and adjusting the car and found that the springs I was using were way to hard (Green progressive on the back and Red progressive in the front).

If you want to check what this 115/38 means when compared with your own ratio, use the Gear Calculator below.

Now I'm using Pink linear springs front and rear, with 60 oil. 2 mm spacers on the front and 3 mm spacers on the back. The tires are Pro-Line LP Slick 2 H13 and the grip is awesome. I can lap VERY fast with this combination. So fast that some people take me for a pro. If you read this page you would see lap times of 29 to 31 in the beginning. Well, now my best time is 24.05 seconds. Amazing isn't it? It's not just a fast lap, it's VEERY close to the track record

. I've got skills!!!

A small skirmish with a Kyosho GP WC MkII was decided in my favor several times

. The top speed is incredible and the car is behaving like a train on the curves.

The surprise came at night at home. I installed the aluminum setup wheels to measure all the angles and they were like this:

Strange isn't it? Well it works! LOL. I wrote down this bizarre setup and tuned the car in a logical way. I have to see if the results are the same. If not, I'll twist the car all over again.

Electric (Electronic) components
Motor	Team Orion Chrome Touring 11x3 or Corally 10x2 or Fantom 10x3 or "Corallynity" 9x2 (see Motors to know why and when)
ESC	Novak Cyclone TC
Batteries	Sanyo 2000 or 3000, Panasonic 3000, Corally 2400 saddle
Connectors	Astro Flight and Corally
Receiver	Multiplex Pico 4/5 40Mhz
Steering Servo	Multiplex Profi 3 BB
Transmission
Pinion	38t 64 pitch (Robinson Racing)
Spur	115t 64 pitch (Robinson Racing)
Chassis and suspension
Front camber	-1º
Front toe	0º
Rear camber	-1.5º
Rear toe	2º toe in
Front springs	Yellow progressive
Rear springs	White Progressive
Rear sway bar	red
Tires
Front	Pro-Line LP-Slick 2 H13 Red HPI Molded Inserts or Pit Shimizu Inch UP (D20 and D25)
Rear	Pro-Line LP-Slick 2 H13 Black Jaco Molded Inserts or Pit Shimizu Inch UP (D20 and D25)
Hop Ups
Steering	2 Ball bearings
Graphite front suspension mount	HPI
Graphite rear suspension mount	HPI
Graphite Outdrives	HPI
Aluminum diff pulley	Robinson Racing
Aluminum diff pulley	Robinson Racing
Aluminum center pulleys	Robinson Racing
Upper suspension mount front	Integy
Upper suspension mount rear	Integy
Spur mount	HPI
Motor plate	HPI
Linear Springs	HPI
Front Hubs	Integy
Rear Hubs	Integy (now removed)
Wheel Hex adapters	Hammad Ghuman

That strange setup was not necessary. The present angles (see table above) make the car behave correctly.
I was doing some practice laps and at the track there was one of our top drivers (3rd or 4th national). He was impressed with the top speed and the cornering speed of my car.

I'm not at his level of driving, but he noticed some potential on the car. He drives a very hopped up TC3. He asked me if he could run a complete pack with my car. Of course I let him do it, because good advice is always welcome.

After a lap or two getting used to the radio and car, he opened the throttle. He made a set of incredible laps. Fine driving. When he came down from the driving stand I asked - "So ? What do you think ?". His smile said it all. Perfect! Very fast (really very fast), wonderful corner speed and handling and SILENCE! That car is a very silent bullet. Two days later he went to the shop and bought one HPI RS4 Pro 2...

I saw him practice with the TC3 and I can say that he was lapping as fast with my car. I'll carve this setup in stone, and I'll take care of this motor as if it was a jewel...

He was really amazed with the motor, an Orion Chrome Touring 11x3 that was cold after the run.

The front suspension mount by Integy. You can see the shims I needed to stop the incredible slop. When I first installed it, I was so frustrated that I picked the plastic part again to install it in the car.

I changed the ESC, Tekin G12CIII, for a Novak Cyclone TC. It's smaller, but there are two or three details that make me like the Tekin ESC's (especially the G-10) more and more.

The G-10 doesn't even get warm, and the tuning capabilities are endless. I rest my case.

I also installed three new hopups. The graphite suspension mounts and the center aluminum bulkhead (7027). I'm not sure about the practical results, but the looks (as you may know) are better.

I guess that all of us desired to have a car like no one else in terms of speed and handling. Speed has a limit imposed by the motor and the batteries we can get. Handling ais another matter. I tried to solve the first variable using a brushless motor. And it is now installed on the HPI PRO 2.

This motor can be powered up to 12 cells and it has a rpm limit of 100.000!! This limit is imposed by the motor controller, but I wont need to reach that rpm to blow away any 9 or 10 motor on the track. The power that this motor delivers is above ANY of them (I guess I should include 8 and 7).

There are no brushes to change, commutator to skim, no springs and no dust caused by brush wearing.

It's has an efficiency above 85% with a power curve able to cause envy to a .15 nitro owner.

The only problem can be the tires and the handling of the car. This thing makes the car spin in all four wheels if you apply the throttle too fast on a straight. I guess that I've solved the power problem.

It can be considered a bit pricey, but the cost of running this motor is 0 (yes ZERO). If I take care of him and it'll last all my RC life (kicking all the brushed motors the other racers throw at me).

Keep coming to the site, because I'll post the testing results next week when I race it for the first time. I chose the practice day before the 1st race of the season just to post pictures of the other racers faces

This is the last (12/09/2000) chassis configuration. If you press some areas of the photo, you can see details of the chassis.

I felt at some point in my RC career that this car was somewhat limited. The truth is that I was limited. I went to the Yokomo and after that to the Xray T1. This last car (similar in concept to the Pro 2) had an excellent manual for tuning. And I was able to be really fast with it.

I came back to the Pro 2 and applied what I've learned with the Xray. I found so many mistakes that I could not believe it. Some of the mistakes were my fault and some of them were incorrect tips printed on the manual. The most (and very critical) one is the suggested shock length and no indication of droop setting in spite of the droops screws being there.

I started to tinker with the car and finally I have a suspension that looks like is doing what is supposed to do. Without this achieving the correct ride height and suspension behavior was nearly impossible.

Chassis and suspension

8/20/2001

This car needs some drastic changes if you built it like the manual states.

After setting up the Xray T1 I came back to the Pro 2 and applied what I've learned. This is the current setup.

Now the suspension can have that name. Trying to tune the car with that suggestion of 62mm shocks (like in the manual) will get you nowhere.

This is why experience is so important. I would never do it at the beginning. Now I know how a suspension must look like.

11/22/2001

Every time I run this car I find it more and more tuned to my liking.
This test was done with the new 12x1 from Reedy since next year we have a 12 turn limitation. The track was very slippery, very cold and the car had to be driven with a light and precise hand.
Once more a top driver said that the setup was awesome. He tried it and he liked it very much.

So did I. Excellent handling on a very complocated track.

I would never imagined to be so fond of this car. I can see that more and more at the track. People just don't like the Pro 3. The second hand Pro 2 is becoming an asset.

I had an entry on the Guestbook from Iceland, asking me to put the PN's of the HPI Springs I'm using. Because there was no email address there, I hope that Sigurdur sees this update. BTW I was looking at the URL he pointed and I could not read a SINGLE WORD!!! LOL. I am a complete illiterate in Icelandic!!

The Blue Linear Spring are PN #6847 and the Pink Linear are PN #6849. Sometimes I go up a little and use the Yellow and White Progressive springs and their PN's are #6833 and #6834.

The other new thing is the new Orion Pro Lap Counting System. I received it today (2001/10/09) and it's already in place waiting to be tested. I have this strange idea that a lap counting system may help me go faster (poor me, how wrong I am).

I was right about this car. It is wonderful. I raced with it and I got my best result on electric races. I could have done better if it wasn't for an error or two.

The car behaved wonderfully and after getting the right tires I could pass a lot of cars holding the inside line. It was doing what I wanted. However acceleration due to that slipping diff allowed them to stay in my tail. Otherwise I would just go and catch the next one.

I got rid of the front suspension mount. I had the aluminium Integy mount and the slop I was finding was really bothering me.

Very simple to do. Just two 20mm turnbuckles, 4 captive balls (maybe from HPI or any other brand) and two of them were already there, 4 aluminium washers (the silver ones that you see close to the shock tower are going to be replaced by purple ones because I can't stand that horrible silver in there

), two long 3mm machine screws (around 16mm) two nylon lock nuts and you're done.

When I went to the track and saw everybody using Dodge Stratus or Alfa 156 bodies I wondered why. And I asked...
They all said amazing things about the differences of handling of those two bodies and all the rest (Honda Accord excluded).

Being the skeptic that I am , I just attributed this to the "me too" phenomenon, and decided to make my own testing.

One day (9/9/2000) I took the Lexus and the Alfa bodies to the track and tried them both (the body was the only thing I changed). After running the Alfa body I changed to the Lexus, and I could not hold the rear on the curves, decreasing my lap times from 23-24 seconds to 25-26. I tried to adjust other variables, but even with a slight improvement there was no way I could reach those mythical 23 seconds per lap.

Again, I installed the Alfa. Amazing, the rear was perfect hooking up like glue and the lap times decreased again to 23.9, 24.2 with a best of 23.2 seconds per lap.

It seems it's not a myth. It really changes the behavior of the car. Now I'm glad that I have a Stratus body (HPI painted by Team Orion). I could do even better. Let's wait and see.

Want to save some time painting? You have two choices. Either you buy a painted HPI body from Team Orion (double or triple price of a normal body), or you buy the decals from Thunder Designs. It will look good, no matter what you do.

If I look back (when the Integra body was still in one piece) I guess that the Integra body is far better than the Lexus IS200. The Lexus IS200 will stand on the shelf on display. After all, it was the Lexus body that entered the HPI gallery.

Experience shows that bodies wear more than tires, so I have an Alfa Romeo 156 painted and ready to use, and I got two more bodies from Apex Models in the UK, just in case. When you buy one for £16 you can have another one for £5, and I couldn't pass such a generous offer :-).

A word of warning - If you are starting in RC cars and you are on a limited budget, you probably want a cheaper car. If you are not disciplined in spending, this stuff can really ruin you. Beware! 80% of the stuff is virtually useless if you don't know how to drive really well. Your hands are 80%, and the material is the remainder 20%!

I've seen guys at the track with so much material (one of them had so many matched battery packs in a suitcase that I could buy all my material just with the cost of those batteries), that they probably are paying loans for that material :-).

In the end, they crash a lot on the finals and even allow the packs to dump! The guy that drives better (less crashes) wins.

If I did those perfect 14 laps (between 29.5 and 31) on a final I would probably be 1st or 2nd.

Electric (Electronic) components
Motor	Team Orion Chrome Touring 11x3 or Corally 10x2 or Fantom 10x3 or "Corallynity" 9x2 (see Motors to know why and when)
ESC	Novak Cyclone TC
Batteries	Sanyo 2000 or 3000, Panasonic 3000, Corally 2400 saddle
Connectors	Astro Flight and Corally
Receiver	Multiplex Pico 4/5 40Mhz
Steering Servo	Multiplex Profi 3 BB
Chassis and suspension
Front camber	-1º
Front toe	0º
Rear camber	-1.5º
Rear toe	2º toe in
Front springs	Yellow progressive
Rear springs	White Progressive
Rear sway bar	red
Hop Ups
Steering	2 Ball bearings
Graphite front suspension mount	HPI
Graphite rear suspension mount	HPI
Graphite Outdrives	HPI
Aluminum diff pulley	Robinson Racing
Aluminum diff pulley	Robinson Racing
Aluminum center pulleys	Robinson Racing
Upper suspension mount front	Integy
Upper suspension mount rear	Integy
Spur mount	HPI
Motor plate	HPI
Linear Springs	HPI
Front Hubs	Integy
Wheel Hex adapters	Hammad Ghuman

Here you have 4 pictures of the chassis, that provide a better idea of how the car looks like.
By pressing the picture you'll see a much bigger picture with all the details clearly visible.