Sunday, January 30, 2011

Foam tire F104 revisited

I had the chance to make a run after racing this Sunday with the F104 in TCS foam tire trim. Previously, I had a traction roll problem due to improper rear ride height. With the car's axle height properly set, it was extremely good. Plenty of steering and it carved around the corners, and I was able to stay close to the barriers-very linear feel to the steering. I may be able to do a bit more by mid week, so stay tuned.

Exotek 104

Challenge Formula One

I just wanted to briefly mention the Challenge Formula One site. Todd Marshall started the site, and has a bunch of good stuff on there. I have contributed, along with Greg Sharpe, a TCS F1 Regional Champ. Todd was on a bit of a hiatus, but he's back now, so more good stuff should be coming in the future.

F103 Overview

One thing I forgot to mention in the video, I use a 1mm hex spacer for a touring car to add a bit of caster to the front end. The spacer goes under the front suspension on the forward screw to add a bit of kick. This helps calm the car off center.

Monday, January 24, 2011

F1 Arbors and the long long wait.........

I have 3 setups for F1 tire truing. You might ask "What is your problem?", since it might be right to ask why I have 3 sets of arbors. The real deal is that arbors are hard to find, and usually kind of crappy. I have done stuff like using a left side hub to true tires, or a 1/12 arbor, which is actually not bad for 103 fronts. Here's some of the actual tools...

The one on the far right is from D Drive in Japan, if I remember right. I think it might be an Eagle. It pretty much sucked from the get go. It would never correctly grip the motor shaft on my truer, to the point that I drilled and tapped a set screw. Half the time it seemed to wobble anyway.

The middle set is made by the same guy who used to build the MaxMod truers. They're bar stock aluminum. They also are a bit different. The arbor threads onto the shaft and is secured by a set screw/threaded shaft for the thumbscrew that holds the wheel on to the arbor. Not a bad idea, but the set screw is just a black oxide coarse thread grub screw. Sometimes it gets a bit off kilter and is less than true. This is a problem for the fronts more than the rears. The other thing is that there are separate arbors for front and rear, and an extra plate to do 104 fronts. Not horrible problems, just less than ideal. Also a problem if your truer's motor does not have a threaded shaft. I was glad to have them after dealing with the Eagle Annoy-O-Matic arbor.

Finally, we have the arbor I've been waiting for all my life...the Exotek. One piece to work on all your different tires, clamps like a vise, and very true. It's made like any other well done pan car or sedan arbor. Yay. Also, easy to get in the USA from Exotek or stores who deal with him. I'm seriously impressed.

A day at the races

I took a ride out of town to race a regional series race in Wisconsin. I was really there to race sedans, but they were saying they would have F1 as well as an extra class. I wound up with 3 classes to run, so I didn't do a ton of fooling with the car. I was also racing 8 minute heats since they combined F1 with 1/12..the class was more of a fun thing than anything else.

The point of all this is that I took the chance to run my Exotek with the 103 front end and tires, and my F103. At my home track, which remains fairly high traction most of the time, these cars produce almost identical lap times. The F103 is actually a fiberglass chassis car that started as a 15th anniversary. The fiberglass chassis seems to be hooked up in most situations however.

I ran the Exotek a few times, as I really like the car. I think since it's a bit longer than a standard F103, it is easier to drive most of the time. The track was still throwing off a lot of fuzz, and didn't have a ton of traction built up yet. It also was in a building that was about 100 years old, having a board floor vs. plywood. The floor was not in bad shape, but it was not perfectly smooth, so the pan cars chattered around a bit. The problem I was having was that the car would want to slide or wash out on 2 left hand turns. I wasn't sure if it was tweak or the floor. It also would sort of bind up if you used too much wheel input in the right hand sweeper at the end of the straight. It felt like it was either lifting a front wheel or rolling the chassis over too far. Kind of weird. This was probably from being too light on the side shock and center shock dampening. I was using CRC red side springs as well, which may have been too heavy. I changed dampening to 50 wt for both side and main shocks.

It got better and cut down on the chattering. It still wanted to slide a bit on the lefts. I also went to the medium gold front spring as well so the car let thr front end roll a bit more. Overall, the car wasn't bad, but it was a bit blah and not really fast.

I also ran the F103, which wound up being very good. This did surprise me a bit, but I have had a similar situation last year where the fiberglass chassis/long fiberglass upper deck was the hot ticket. It just seems that the extra flex seals the deal in lower traction. I actually used the same set of tires on the F103 as the Exotek. I actually did not change anything from my home track except to loosen the t bar a bit. One difference with the F103 is that it's fairly heavily dampened, so i could have possibly gone even higher on the Exotek car. The 103 car did slide a bit in the same corners as the Exotek, but it was better. In the main, the 103 ran about 3/4 of a lap off of the 1/12 17.5 open speedo car's time. I could also see he did have a h.p. advantage over the silvercan, so that actually was a pretty good result.

As far as the Exotek, what could I have done to get it working? I think a lighter side spring would have been better. Stiffer side to side dampening as well. I think it was skipping around as bit due to the floor. I would have wanted to go heavier dampening just to slow the roll in the sweeper and other corners as well. Maybe even o rings under the upper deck screws that attach to the servo mount. I wish I had more time, but I was running 3 classes, so I just put the car on the track that worked the best. That is the beauty part of a basic 103, you don't really even need all the optional parts. A motor mount, a shock, and a long upper deck and you should be good at most tracks.

Speaking of which, here's how the 103 upper decks play out-
Long carbon upper deck- definitely has most response/steering, but may be too stiff if there is not enough traction.

Long fiberglass upper deck - probably the best balance between chassis stiffness and steering response. Good for the majority of situations, even high bite.

Short fiberglass upper deck - steering feel is dead, not very good response. I think the front of the car flexes too much. Might be good for very low traction, or if you are trying to kill response.

Basically, the car steers more as it gets stiffer, but it also becomes more nervous. One way to reduce this is to run a o ring under the 2 screws that attach the upper deck to the servo mount. I do this a majority of the time, even with the fiberglass setup.

I did a back to back last year with all these parts.

Monday, January 17, 2011

Foam Tire Week 2

I'll probably have a video later, but for now I'll detail what happened at the track.  I cut some new tires, both A & B compound for the day to see what was what.  The layout was new, so the track was somewhat green.  I left the car basically as it was from the last practice day.

B compound tires worked very well on the green track.  I ran them several times until the car wanted to traction roll a bit.  I thought maybe the tires were a bit much as the traction was coming up, so I switched to A tires.  The A tires still wanted to traction roll as well.  This is where I save some time by telling you that I forgot to change the axle cams when I went from 55.5mm rears to 59mm rears.  I was probably at about 5-5.5mm ride height in the back, wondering why my car was traction rolling.  The front was 4mm, but the rear was just too high, not to mention the rake was not helping.  Anyway, while not paying attention to this, I did have a chance to try a bunch of stuff on the front end to tame it.

I kept the lowered position of the front camber plate.  However, I began to raise the ballstud to take away a bit of the active caster.  I also moved the ride height shims around on the outer part of the arm to change the camber gain as well.  Just dropping the plate gives a steeply angled front arm that gives a lot of camber change, and excess static camber as well. Moving ride height spacers from between the top of the sterring knuckle and the bottom of the upper arm, to the top of the upper arm changes the angle of the upper arm.  You can put the spacers on top of the arm to kill some of the camber and maintain a similar active caster angle.  This was helpful in reducing the traction roll.  You could see it was excessive front bite by the way the chassis would overpower the t bar/damper plate, and make it lift a front tire before the inside rear followed. 

I wound up trying a "soft" t bar vs. the "flex" t bar with the u cut out, just to keep the twisting down.  This did help, but it killed the rotation as I figured it would.  Not that the car didn't turn, but it was very flat, and slid the rears vs. letting the chassis roll and rotate the car.  This felt a bit bound up mid corner.

Around that time I remembered I had never changed the axle cam, and once I got my rear ride height to 4mm, the car had not the slightest tendency to traction roll.  What did happen was the front end of the car did feel a bit dead.  It actually turned fairly well, and was very nice off center, but didn't have quite enough steering.  By this point I had spaced the ballstud on the camber plate up 3mm, I reduced this to 2mm, and got back some steering.  I didn't change the ride height spacers at all. 

I had a chance to run most of the day with my buddy Jimmy's 21.5/no timing esc equipped 104, which had the front end set up normally, but was pretty dialed in.  It was nice to see what lap times he had as a baseline.  I either matched or was off his hotlap by .1, but he had more hotlaps and a better average.  He did have more rip out of the hole, so that was to be expected a bit.  I gave the radio to my friend Kevin for some laps, and he could hang with Jimmy no problem as well, and with a car he never drove before.  That does seem like a good thing.  The car is definitely good, but I need to re evaluate the front end again, since I wasted a bunch of time with the traction roll problem that probably is not a problem.  I think that I will be able to go back to a more aggressive front end setting and have additional steering without lifting tires.  The nice part is that I know what to do to keep the car feeling very neutral and easy to drive and still have steering.  It should not be hard to balance that with the amount of steering needed on a small carpet track.

Sunday, January 9, 2011

Foam tire extras

Stuff I forgot to mention on video:
Black front spring (stiffest), 100K diff oil in kingpins, all spacers on top of steering arm

7g lead in front of servo, 14g behind servo, 28g on RX, 14g each on left and right sides of battery, 7g each on left and right of diffuser.  Some of this weight may not be necessary for foam.  91g total.

#1 ride height adjuster, axle in low position--tire size ~55.5mm

3.5mm of thread showing on damper post

25/93--46.87mm rollout--may need a bigger spur for this track, turns are tight

Tire mounting

A way to mount foams.....

Foam tire F104

Here's a couple quick thoughts on F104 foam tire setup...will have some more details coming up

Friday, January 7, 2011

Servo mounting

Here's a couple pics of the way the servo was mounted in the car. 

Tuesday, January 4, 2011

Now it can be told! The TCS Nats Story Part 4

Sunday came and it was basically make or break in the last qualifier. The one advantage I had was that I would be up front in the B for this race, and I wouldn't have to contend with the usual last round banzai moves that happen at most races in the A qualifier.

As luck would have it, the sun was out for my qualifier, and the track temperature seemed to favor whatever I was doing with tires. The car was driveable, fairly fast even. I got into the lead on the clock, and had a good run, up until the last few seconds. I was trying to get around a backmarker who may not have known I was leading. I managed to get tangled up for a couple seconds, but nothing really bad. I won my race, and had fast time for the round until the A group came up. The A heat came out, and luckily, my time wound up being good for 4th or 5th in the round, which was enough in combination with Saturday's runs to put me 8th in the A main. Not too bad after all...

I didn't have too much strategy for the mains. Realistically, I had no shot coming out of an 8 spot. I knew my car wasn't really fast enough to compete with the top cars. I was a couple tenths off on hot lap, and they were doing more of the fast laps than I was. I just figured I would see if could get a few spots better than I qualified.

I switched to the 3200 battery for the mains as well, not knowing if the 1800 would make an 8 minute race. Based on what I was putting back into the battery for the heat races, I was leery of trying to push it.

The first race went off pretty well. The start was a bit chaotic, and I was able to take advantage and pick up a couple spots while everybody shuffled around. The problem was just that my car couldn't hold my position. I went backwards toward the middle of the race, and wound up finishing 8th, where I started.

After the first race, I wound up putting some lead near the back of the chassis just because the larger battery biased a little more weight on the nose. I didn't really change anything else. I felt like if the track came to me I could maybe get a couple places off the start and try to hold on. It just depended on the car.

The second A was a good start for me. I was able to get up to 5th on the first lap, and fell back to 6th. One of the top five cars got spun off the start and wound up getting behind me and then passed me. At some point, another car caught a curb or something, and I wound up finishing fifth. That was my best race of the mains, and it was also the best my car worked beside the qualifier in the morning. The tires actually seemed to get better as the race went on (???). I was still a lap off of the pace, but finishing 3 spots higher than my start was nice.

For the final A, I figured I would just go for broke. I put the 1800 back in, as if I didn't finish, it wouldn't matter anyway. I also decided to try a newer set of tires with the same insert, thinking maybe they might be a little better.

The third A was basically a washout for me. The tires were definitely not as good as the original set. The way things turned out, I could have brought one set of tires for the whole weekend. The first set I had done a ton of running on at home were the only ones that seemed to work. At one point in the chicane going on the straight, I got blasted pretty hard. I'm not even sure what happened (probably my fault anyway), but I rolled it around the track in 10th place for the rest of the race and tried to stay out of the way. The one good thing was that the 1800 made 8 minutes with no problem.

What can you take away from all this long winded baloney?  Well, I would say for F1 at the Tamiya track, tires are the #1 tuning area far and away.  It's very critical, and the insert is a big part of it.  I was told stock inserts are what work, so I guess that's the place to start.  If you plan to go out there, I'd recommend trying to practice on a sealed parking lot or maybe even a tennis court with no traction enhancement, just blow the dust off.  The other part of the equation would be to just get the rear end of your car as planted as possible.  Being able to use the throttle is key, and if your car is loose, you're done.  A safe car you can bang the wheel back and forth on is what you're trying to achieve.  As they say, "You can't fire a cannon from a canoe..."

I'll be back to try again in 2011...

Videos of mains:

Now it can be told! The TCS Nats Story Part 3

Friday we returned to the track in the morning for day 2 of practice. To some extent I was worried since track time was going to become more scare as the track got more crowded, and they would be going to controlled practice at some point as well.

I settled on sticking with the 1800 mAh micro car pack that had shown a huge lap time advantage at my home track. At home, on the higher bite surface, the 95g pack saving close to 100g over a normal sized 3200 lipo pack, made the car much faster in a straight line. Not only that, it was also much more nimble and quicker reacting. That was actually a minus at this point. I should have went with the heavier pack, hopefully getting some stability back. Anytime there is good bite, the small pack is a great advantage. Even when the traction is only average, you can still add lead exactly where you want it, and be on par with normal sized packs in terms of overall weight.

Tires where also a tough part of the equation. I went with what I at least knew worked ok at home, which was kit front tires and the optional soft rear, with "low bounce", memory foam type inserts. I didn't like the stock insert only because there was no air gap at all. For sedan tires, some air gap is usually a positive, since the tires can be easy to overheat if they don't have any gap at all. I did try a couple other setups as well, but the old reliable seemed to be the best of what I had. I was also using my tire warmer routine. The other thing was newer tires I built up using the low bounce inserts didn't seem to be as good as my old worn out set. At the same time, what I could gather from the other racers was that newer tires with stock inserts was the way to go. No tire prep other than cleaning. I tried this as well, but I don't know if I was cleaning the same way they were.

Racing around during practice, I could see may car was ok, and on certain runs, good. My car seemed to be better around noon time. I could tell there were 3 or 4 cars that were faster than mine for sure. At the same time, there were some fast cars that had a front end hop. Mine had this hop as well. I was fairly sure it was from running the stiff black springs with fairly light grease on the front kingpins. At the same time, it seemed like you might have to live with it to get the car around. I left practice feeling a bit confused.

Saturday came, and I was probably less than confident. I had run into JB Catricala on Friday. He was with the Tamiya Canada crew. I knew JB from big carpet races in the Midwest. He was asking about what I was trying for setup, as the Canadian F1 guys were trying to get their bearings. Saturday, I was in the Canadian pits, and Tom from Tamiya Canada offered some of his advice on what they found worked for them. Tom was super cool about offering up what they knew, which was a much different tire setup than what I had, as well as some different chassis settings.

The problem was there really wasn't time to practice much with this new stuff. I wound up trying the tire deal in my first qualifier. This new info I hoped would get my car where it needed to be. At the same time, I had a feeling that it just might not be right for me. After a while, you get a feel for what works for you in terms of setup, but I had been trying a lot of stuff that didn't do a ton for me. So I decided to gamble, and I went with it. The car wound up being ok, but not really what I was looking for. I did not have all the details of the setup ready for the first qualifier, so I got the rest squared away for the second race. Unfortunately, the results were similar. I crapped out on my bet. I'm not really sure the way I had the car setup originally was any better, but I was at least familiar with how it drove. I also would have been able to make some improvement to what I had between rounds. It was totally my decision to change my car, though probably a bad one.

Todd Marshall, of "Challenge F1" fame, was pitting right across the way from me. Being more of a carpet guy himself, we commiserated over our plights during the course of the weekend. He wound up trying rear tires with no insert at all, and also scuffing the tire on a tire truer. I watched his car, and it looked pretty good. For the last qualifier, I figured it couldn't hurt to try what he had, so I made up some tires like his. I ran those tires in the last qualifier of the day, and again, it was not any better than what I had before. In the end, I wound up 11th overall with one qualifier left on Sunday.

At that time, I was mad at myself, but I only had myself to blame. My friend Chris Goetz (known as Seaball on rctech), had told me one time that you just have to live with your car at some point during a big event, that you stop changing it and just drive it. I broke this rule pretty badly. I didn't have confidence in my abilities to get the car right, and I wound up flailing. If I had just run what I had, I felt I could have at least been in the main on Saturday. This is probably the biggest lesson for racing at the Tamiya facility or any other big race. At some point you have to have confidence in your knowledge and just make a decision to drive the car.

Saturday night, I decided to rebuild the car based on what I thought it should be. I knew if I had a good run Sunday morning, I could at least put it in the show. Over the course of a couple hours, I got the car into the shape I wanted it, and put the one set of tires I knew worked reliably on it. Sunday morning would show if I had any chance to salvage the weekend.


Now it can be told! The TCS Nats Story Part 2

The Tamiya track on arrival is really impressive, but one thing to note is that it's not as large as it looks like in the magazines.  It's not like some giant gas car track.  It's actually very suited for 1/10 electric cars.  It definitely would be an awesome facility to be able to run on a weekly basis.

The problem that I had first off was that my case full of equipment didn't fly out on my plane, so all I had was my car, radio, battery and the tires on the car.  Luckily, Marty and the Passehls were able to loan me a charger and tools.   The first day of practice just wound up being getting to know the track and trying different ways of saucing the tires without warmers.  The tires I had on the car were correct,  but  they had cut down sedan inserts in all 4 tires.  This proved to be very hard to drive on the Tamiya track.  I guess a change of tires, a charger and a couple wrenches are going in the carry on next time...

I was watching the F1 cars going around the track, just to see what the cars looked like.  The one car that stood out to me was Craig "F'n Cuda" Hammond's car.  It looked just easy to drive, not doing anything fancy, but getting around the track well.  If anything, I thought he could have gotten some of the push out of it, but it would turn out I should have copied his car and started from there.

Most races I have been to start where the cars are sort of ok, and then people start dialing their stuff in.  I watched Craig's car, and thought it looked "safe" and easy to drive, but I expected there to be someone who would roll a car out that was just sick, and had wicked steering, and a ton of bite.  Really, the biggest challenge for the Tamiya track is to get positive forward bite and have the car stable.  My car required tip toeing around a lot of the track. It was really a handful in any chicane areas on the track, since the car didn't have enough rear bite to go fast in the back and forth transitions.  As the weekend went on, it became obvious that a stable car was going to be better.

Eventually, my luggage arrived late in the afternoon.  I was at least able to change a few things around, like using some different tires and changing to 3.5mm offset front blocks to try to get a handle on things.  Things were a little better, as tires with a softer insert helped to get the car where it could get around the track without feeling too loose.  I still had that feeling that there was "more out there" as far as overall performance, which in retrospect really wasn't true.  That's a lesson in separating what perception and reality are.

Monday, January 3, 2011

Now it can be told! The TCS Nats Story Part 1

I guess that this is the sort of thing that ends with the lesson, "It's hard to beat a guy on his own pool table."

Last year I ran a couple TCS regionals in F103 and F104.  I won F103 in Omaha, and F103 and F104 at Trackside in Wisconsin.  These were foam tire carpet races, but I felt good about going out to the TCS Nats.  I had the whole summer to test on the 3 outdoor tracks near Chicago, 2 parking lots and Leisure Hours, a tremendous purpose built track with curbs and even a dogleg kind of like the Tamiya track kink.  Dialed.

The thing about all these tracks is that they are all prepared with sugar water or grape soda or something similar.  This is a key point: If you go out there, practice someplace with NO SUGAR.  LOL.  That was my greatest problem.  My car was up on rails on these high bite tracks.  Tamiya is kinda like a tennis court.  The asphalt has bite, but they did not spray with any pop or soda.  They blew it off every morning, and you could actually see that rubber was on the track from all the cars. 

The other thing was tire preparation.  These sprayed tracks respond very well to typical sedan tire tricks. I had a good routine going with tire warmers, and a combination of Paragon FX (white can) and SXT 1.0 and 3.0.  This was not very effective overall at the Tamiya facility.  I did see one other guy with warmers on his car in F1, but I don't know what he was doing otherwise.  He did have a pretty dialed in car, however and came in in the top of the main.  Most driver seemed to be just cleaning their tires, and that was it.  I also found that my car was best on  very old tires with the tire prep I was doing.  This was in contrast to what I found at home, where a new set made the car much faster.  Strangely enough, it did appear that a lot of the faster guys were running new tires, or a combination of new and scuffed tires. 

I was warned by long time Tamiya Nats attendee Marty Hageman that it was going to be different out there.  He had been out in the spring, and said F1 could be hard to hook up.  I had confidence, however, since my car had been getting better all summer, and I would be getting there nice and early for the first day of practice.  There would be no reason why I would not get a ton of runs in and be able to dial my self in properly.....