Saturday, February 26, 2011
Monday, February 21, 2011
TCS HobbyPlex Omaha 2011
Just some notes from the first Tamiya race of the year:
I got a chance to run on the HobbyPlex Omaha track for their TCS race. The bite was very high, as they had used the same layout for a recent enduro race. Luckily, my home track is pretty high bite too, but this was even more so.
The biggest thing was being able to dial in the front end adjustments in actual competition. Some of the stuff I was doing was ok for practice or screwing around, but the need to put in consistent laps/runs more clearly defines your setup.
I found out I needed to keep the spacers under the ball studs for the upper arm in the 2-3mm range. .5mm is an adjustment step that can be felt on the track. I started with 2mm, went down to 1.5mm, and up to 2.5mm. 1.5mm was too much front grip with the amount of traction out there. 2mm was ok, but 2.5 had the best feel for a neutral, linear steering car. It started out with the same feel as it ended.
Similarly, I did try more height on the kingpin on the upper arm. I default to to the largest ride height spacer on top of the arm. I tried the medium spacer, so the upper arm has a bit more inclination/camber gain. This produced a bit more of a twitchy feeling, and I went back to the large spacer on top of the arm-less height at the kingpin.
To put it in a nutshell, the lower and flatter the upper arm, the more the car will have a linear steering feel, and will be easier to drive in higher traction conditions. This is important as you can then start varying the tire traction to gain the amount of steering you want without making the car hard to drive. I coated 1/3 of the front, but I may have been able to do more. I didn't want to experiment too much in the mains. I think that 3mm under the ball stud on the camber plate would let me run 1/2 or even more dope on the front tire. This is important as I could go faster if the car had more steering. I was able to go .1 sec faster on hot lap and also have more fast laps with my car in the second round of qualifying. However, the car was difficult to drive (this was with 1.5mm spacers on the camber plate ball stud). My average lap was better with the more neutral car, but i could feel that it was a tick slower. More steering would deliver better lap times.
The picture below will show the black groove condition of the track-->
Track Photo
I got a chance to run on the HobbyPlex Omaha track for their TCS race. The bite was very high, as they had used the same layout for a recent enduro race. Luckily, my home track is pretty high bite too, but this was even more so.
The biggest thing was being able to dial in the front end adjustments in actual competition. Some of the stuff I was doing was ok for practice or screwing around, but the need to put in consistent laps/runs more clearly defines your setup.
I found out I needed to keep the spacers under the ball studs for the upper arm in the 2-3mm range. .5mm is an adjustment step that can be felt on the track. I started with 2mm, went down to 1.5mm, and up to 2.5mm. 1.5mm was too much front grip with the amount of traction out there. 2mm was ok, but 2.5 had the best feel for a neutral, linear steering car. It started out with the same feel as it ended.
Similarly, I did try more height on the kingpin on the upper arm. I default to to the largest ride height spacer on top of the arm. I tried the medium spacer, so the upper arm has a bit more inclination/camber gain. This produced a bit more of a twitchy feeling, and I went back to the large spacer on top of the arm-less height at the kingpin.
To put it in a nutshell, the lower and flatter the upper arm, the more the car will have a linear steering feel, and will be easier to drive in higher traction conditions. This is important as you can then start varying the tire traction to gain the amount of steering you want without making the car hard to drive. I coated 1/3 of the front, but I may have been able to do more. I didn't want to experiment too much in the mains. I think that 3mm under the ball stud on the camber plate would let me run 1/2 or even more dope on the front tire. This is important as I could go faster if the car had more steering. I was able to go .1 sec faster on hot lap and also have more fast laps with my car in the second round of qualifying. However, the car was difficult to drive (this was with 1.5mm spacers on the camber plate ball stud). My average lap was better with the more neutral car, but i could feel that it was a tick slower. More steering would deliver better lap times.
The picture below will show the black groove condition of the track-->
Track Photo
Wednesday, February 9, 2011
More fun with the F104 front end
I got back to the track tonight and had a chance to play around a little with the 104 front end. I had retained the camber plate dropped down onto the lower arms, no spacer. The upper arm was spaced up 2mm at the camber plate, and the largest spacer was on top of the arm at the king pin. The track was a bit green, low to medium traction. Turn in was good with this setup but the car did wash out a bit mid corner, a symptom of the low grip.
For the second qualifier, I removed the spacer under the upper arm at the camber plate, and moved the large spacer under the upper arm at the king pin. I also doped more of the front tire to try to add a bit more steering as well. This was overkill, as the car now was great in the 180* type corners, but was too twitchy off center, and would roll the chassis too hard in the sweeper unless very little steering travel was used. This made the car look as if it was about to hike a wheel in the air, and killed corner speed.
I went back to the original dope strategy, a little less than 1/2 the front and moved the middle spacer to the top of the kingpin. I would up again with a mid corner push, but the twitchy-ness and chassis roll was much improved.
To dial into this type of track, I would have changed a few things if I had some more time. First off, I would have tried the B foam. That may have saved me from having to change anything. If that was not effective, I think that the original front end settings with more dope on the front tire would have worked a bit better. The lowered camber plate is nice due to the multiple options for setting up the upper arm. I think the most effective use is to lower the front arm and keep it relatively flat by positioning the kingpin spacers properly. That seems to produce a fairly calm and linear steering feel. Too much angle gets the car nervous and has too much mid corner bite at high speed (read:sweepers). The only other way to work with this may have been a stiffer t plate, but it may reduce the rotation too much.
So far, the lowered plate has given me a better steering feel compared to the plate with the spacers underneath. I think it is more nervous with the upper arm/camber plate raised, while not producing as much front end grip.
Overall it was not a bad night, as I was able to stay withing .3 seconds of an F103 on hot lap and average. Anytime you are within .5 of a good F103, you're close to the right pace.
For the second qualifier, I removed the spacer under the upper arm at the camber plate, and moved the large spacer under the upper arm at the king pin. I also doped more of the front tire to try to add a bit more steering as well. This was overkill, as the car now was great in the 180* type corners, but was too twitchy off center, and would roll the chassis too hard in the sweeper unless very little steering travel was used. This made the car look as if it was about to hike a wheel in the air, and killed corner speed.
I went back to the original dope strategy, a little less than 1/2 the front and moved the middle spacer to the top of the kingpin. I would up again with a mid corner push, but the twitchy-ness and chassis roll was much improved.
To dial into this type of track, I would have changed a few things if I had some more time. First off, I would have tried the B foam. That may have saved me from having to change anything. If that was not effective, I think that the original front end settings with more dope on the front tire would have worked a bit better. The lowered camber plate is nice due to the multiple options for setting up the upper arm. I think the most effective use is to lower the front arm and keep it relatively flat by positioning the kingpin spacers properly. That seems to produce a fairly calm and linear steering feel. Too much angle gets the car nervous and has too much mid corner bite at high speed (read:sweepers). The only other way to work with this may have been a stiffer t plate, but it may reduce the rotation too much.
So far, the lowered plate has given me a better steering feel compared to the plate with the spacers underneath. I think it is more nervous with the upper arm/camber plate raised, while not producing as much front end grip.
Overall it was not a bad night, as I was able to stay withing .3 seconds of an F103 on hot lap and average. Anytime you are within .5 of a good F103, you're close to the right pace.
Wednesday, February 2, 2011
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.
Challenge Formula One
http://challengeformulaone.yolasite.com/
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.
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.
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.
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