Monday, July 29, 2013

SP-1 diff item

One quick addition to the Sped Passion SP-1, regarding the diff.  The washer between the conical pressure washers and the diff nut should be replaced with a Tamiya RC Diff Spacer: 58431.  It makes the pressure on the conical washers even and improves the diff action....

Sunday, July 21, 2013

Speed Passion SP-1 ..Caster is faster

I ran the SP-1 again today to try to get a comparison with my other cars, and it was again very close to my other car.  In fact, the qualifier I used it for was virtually identical to my best time with the other car.  To be honest, I didn't even think it had as much motor as the other car but it had a ton of corner speed. 

So, I was thinking about this and it occurred to me that at 10* of caster, the SP-1 probably has one of the highest caster settings of any car out there out of the box.  My local track is a really large track originally built for gas cars, so it's very high speed.  I can really stay on power with the SpeedPassion car. I had to assume that this was one of the major factors, so I added more caster to my other car and that car picked up the pace as well.  Interesting.

Tuesday, July 16, 2013

SpeedPassion SP-1 setup

SpeedPassion SP-1 asphalt setup

Most of what I did to the car was to try to get maximum traction on both ends of the car.  The link toe in was something that I wanted to try and it seemed to be pretty good for the car.  When the traction was up on the track in the main I was able to drive most of the track on power. 

I also added to the steering rack spacers for a total of 3mm to add some angle to the steering rods.  This made the steering a little more aggressive, but the car was making enough traction to handle it.  I did also mount the shock as far forward as possible, which added to the steering.  That may need to be backed off for lower traction tracks, so it might be a good idea to start in the middle hole depending on your track.

Rear droop was pretty minimal, about 1.5mm.  This usually helps keep the car a little more stable off power.

I did also try CRC White side springs and about 2* camber, which was very good when traction was up, but as traction went down after the mains, this was a bit too much. 

Overall, I was very happy with the car right off of the bench.  While I was testing some changes out on my usual car, and the track changes during the day,  ultimately the SP car was .2 second per lap faster on this day.  That is a pretty good result.  If nothing else, the car is at least as fast what I have been running.

SpeedPassion SP-1

I am now in the possession of the new SpeedPassion car, the SP-1.  Like most of the new cars out there it is  a link style car.  The front end is a little different than most, using an upper pivot ball similar to a 1/12 car like the CRC line. It also utilizes a steering rack as well, instead of the traditional direct steering set up.
The build up is a little different than most to get an 190mm legal car with Pit Shimizu tires, so we'll dive in with some photos.

I decided to add another hole for the links in between the two available.  I have noticed some of the cars out there have some angle to the links.  I had Howard Lo of Speed Passion do this to his car and I wanted to be able to try different settings as well.  I drove Howard's car before I built this and I felt like it had a lot of rear grip compared to the typical straight link.  The photo shows a line scribed in the CF with the point of my calipers.  I used the calipers to find the difference of the holes on center, and then I scribed the line by centering the point of the calipers on the edge of the existing holes. I did the same with the pod plate.

Once drilled I finished the holes with a dremel stone bit that happens to be just about perfect as a countersink.

Now I can select multiple angles for the links to get the amount of "link toe" that I want.  The link toe seems to help the car be more planted. UF1 MIDWEST inaugural champion Rick Vessel says this is due to controlling the roll steer inherent in link cars.  Remember that changing the link positions will probably require resetting the "football" pivot.

Note difference in angle in the links !!  Also Tamiya F104V2/RM01 links fit perfectly if you need them in a pinch, or if you want to try their hard carbon version.

While we're at it, you may also want to address the 3mm nuts used on the football pivot.  I am a Dremelin' fool, so I knocked the flanges off 2 serrated 3mm nuts and used those to secure the pivot without rounding out the plastic on the pivot.  Another suggestion is to use a 3mm tap on the nyloc nuts that come with the car so they will hold your setting but not round out the pivot when you need to make adjustments.

Another nice adjustment is the ability to move the shock forward and back on the top deck.  There are 3 holes, though one seems to be designated for the antenna tube.  I don't use an antenna tube, so it's open for shock attachment.  Moving the shock forward will put more weight on the nose end of the car for more steering.  I did have to use a Tamiya long shock end to reach the longest setting however

As far as the front end, you should look at Howard Lo's RCTECH post on the 190mm front end modification.  It has all the changes you need to make to get the front end where it should be on Pit tires. Be aware that the screws should be through the INSIDE holes on the graphite plate, and the OUTSIDE holes on the aluminum cams on the arms!

There are a couple other things as well:
I drilled out the front half of the tension adjustment hole for the lower suspension ball.  This allows a little finer adjustment on the tension by having one side of the arm free. The lower suspension ball is plastic and it is my one gripe with the car.  I had to do some hand finishing and sanding to get the ball free in the arm, and I still was not really pleased with the result.  A little teflon powder helped to free it up but the ball either needs to be metal or the plastic needs to be improved.  An aluminum ball would be perfect here.

.Here you can see I dremeled a slot in the ball retainer to make it easier to thread in and adjust with a flat blade screwdriver.

In lieu of using shims under the steering knuckle, I used a 3mm screw as a droop screw for on the fly adjustment at the track.  Note that you should set the length of the lower kingpins the same on both sides before setting the droop screws.  The easiest way to do this is with a caliper measuring the length of the kingpin past the lower ball.  Mine is at 5.5mm between ball and the lip of the kingpin.

That's most of the car.  I'll elaborate on inital setup in my next post on performance.  Please do note that the spur gear that comes with the car is actually really important.  It has 18 balls, and I think helps contribute to a very smooth but slip free diff.  The extra balls help with a good lock up without too much tension, which is huge on rubber tires.....

Monday, July 1, 2013

Fred Medel of Tamiya USA on the TRF101

Fred posted on Rctech on the new TRF101 and what it does differently on the track:

"Hello All,

I decided to take the TRF101 for a spin. I built one off the shelf to see how I can best share the differences between both platforms.

As most of you may know I have A LOT of time on the V2. About 6 weeks ago I was in Japan talking to the designer of the car. In case anyone wondered it's Kiyo Suzuki. He's the same fellow that travels the world with Marc Rheinard developing the TRF touring cars. The man knows his stuff when designing cars in case you wondered.

In short Kiyo and Satoshi Maezumi told me the new front end changes the way the front end responds to your steering input. Basically, you'll notice it feels more neutral compared to the standard front end. Having driven a million laps with my V2 around the Tamiya track I can confirm that is indeed the case. The V2 is a stable car. However, the 180 hairpin turn after the sweeper has always frustrated me as the V2 wants to continue to turn. You have to be careful after the 180 to keep the car straight to make the inner sweeper. In the past I've tried to fix this with dual rate on the radio and with tire choice and sauce application tricks. With the TRF101 the car enters the turn with immense stability and there is no sign of the car wanting to continue to turn after applying throttle after the 180. It's just that stable. I believe this is the case because you now have a solid front end like the F103 on top of having the side links further apart. With the F104 link front end you have more movement going on with the front end, which makes for some unwanted movement. I didn't think this was an issue before, but it seems like the solid front end cures sensitivity and over-steering. Also, loosening the front screws on the carbon mellows the car out even more. If you think the front carbon piece doesn't move if you loosen it think again. There's a ton of movement. It's a great tuning option. I would suggest making sure the whole is big enough so the screw moves freely with the carbon top piece. Also, Kiyo informed me that I should experiment with using O-rings instead of the steel washers in the middle of the front end. This will make for a softer and dampened front end.

In short...I put two packs throw the car with my V2 starting point set up. It can only get better once I begin to play with more things. For one, the stock instructions have the TRF shock built with too much droop. Surprisingly, the car remained stable at the Tamiya "Kink" even with that much pod droop. Typically, you have to set the V2 with little pod droop to keep the car stable though the kink. Not so with the 101 so it seems, but more testing is needed.

Anyway, I hope everyone is enjoying their new toy. I am. I'll post some pics soon to show how easy it was to get to 4.2mm ride height on the front without having to use shims on the upper arm. At the Tamiya Track lowering the car below 4.2 is not recommended.

Stay tuned..."