IOCC - Las Vegas

Tekno has just released their brand new EB410, 1/10th Electric 4wd buggy to the market, and we took it to Vegas to put it through the paces against some world caliber competition. Joe and I set off last Saturday, where we arrived a little late, and unfortunately missing out on the drivers briefing and included buffet dinner! The location was the WestGate Resort and Casino in Ballroom A where we would be duking it out over the coming week. This would be only my 2nd time running the buggy (last time was maybe 5 packs worth a few months ago on clay) and my first time ever running offroad on carpet. The car is new, our knowledge of the surface was sparse, and we learned quickly it was going to be a team effort to try to compete against the stiff competition.

When we awoke the next morning it was time to get our feet wet and see what we could do. I was first to give it a try and while there is video evidence of the occasion I can't recommend you watch it. I was all over the place and crashing everywhere! Talk about feeling like I just started again. So over the course of the first day I tried lots and lots of set-up changes but nothing really fixing my issues. You see I figured out this weekend I am a "Macro" guy while Joe and Mason are more able to feel the "Micro" changes. So while they can change one thing or two and say it did this or that better, oftentimes I can't feel that. I more or less have an overarching issue that I want corrected (i.e. lifting inside rear, or dumping on the front) and if it can't correct one of those main themes then I can't feel what it actually changed.

As we ended day one Joe and Mason were working together and starting to get closer. I was still a little on my own trying some random and crazy things just seeing if I could get it to work. The Macro themes I was trying to solve were the rear inside lifting, the car dumping hard on the front when cornering, and all in all transferring a lot of weight around on acceleration and braking. At one point I tried smaller holed pistons to try to slow down the roll speed but ran way to heavy oil in them and it was nearly undriveable. At least that answered some things for me. At the end of practice we were getting closer and we headed up to our hotel room to brainstorm over what changes we could make.

We went and looked online at some AE carpet set-up sheets and all of them were saying they were adding 50g behind their motor and their overall weight was around 1800g. Now in the last couple practice sessions I actually put in a smaller 3600 ProTek LiHV and had my car down around 1,640g if I remember correctly. So this made me decide that I should go back to the heavier 4900 ProTek LiHV battery. I also opted to put in a full size Futaba S9373SV servo and we added 50g of weight to the rear of the chassis. Another thing we were trying to fix was the rear bouncing on landing. We were running 1.7x2 pistons front and rear. In looking at those AE set-ups we saw they were running 1.6x2 front and 1.9x2 rear. To me it didn't make sense why we had the same piston front and rear. We did some slow mo drop tests and sure enough we were pack bouncing in the rear. So I figured we should run 1.7x2 front and 2.0x2 rear. So we made some up and they were better for sure. I even decided to run 2.1x2 rear personally to try to get a little more rear roll.

So we got some morning practice before quals started and I believe we all felt we made progress on the rear shocks and adding the weight. The car felt more balanced. Now for Q1 I went out and it was the best it had been but I still felt it was diving on the front a bit to much and lifting the inside rear. I decided to do another change that it looked like most 4wd guys were running and that was to have the same diff oil front and rear. Joe and Mason were running 10-60-4 in theirs and they were happy but for some reason I wasn't. Well when I took my diffs out I saw a mistake I had made. I had put the 5K in the front and 10K in the rear. But instead of just correcting that issue I decided to try the 'square' diff set-up. I went 12-60-12 for my next run along with a few other changes including laying my front shocks all the way in from being one hole higher. For this run my steering got super aggressive and the car was hooking and had a traction roll feel still.

So for Q3 I went to almost the same diffs that Joe and Mason were running which was 10-60-5 (they had 4 in the rear). I also went to -3 camber all the way around and kind of copied Joe and Mason's set-up. It was the best my car had been but still felt to much roll for me. There was some practice after this first day of qualifying and I kept adding front toe out to mellow out the front and it was working. I probably ended up around +3 or +4 degrees of front toe out and it really helped smooth out the steering. I also move the front shock back up one hole on the tower to support it a bit better and my car was the best it had been.

Day 2 of qualifying saw a bit more practice in the morning thankfully. I say that because the night before was an included all you can eat Taco bar for all the participants. Many of the other drivers came over to check out our cars in that time and Maifield gave us a lot of feedback on things he noticed and what he personally does for such high traction carpet. There was some things that we simply couldn't change for this past weekend. He said our body was way to heavy and possibly to high as well. (For sure something we will look into for the future). Also he gave us lots of comments on roll centers and what he likes on his cars. On top of it all said how important it is to have the car flex as much as possible. (Basically he could take his cars and make the shock tower touch if he wanted to it's so flexible. Now we couldn't go so extreme at this race as our parts supply was limited if something were to happen, but it just goes to show you what lengths the pro's go to, to get an edge on the track.) So when we went back to the room Mason and I took his feedback and totally changed the roll centers of the car. We raised the rear roll center a lot, we took out all the anti-squat and rear toe that we were running and lowered the front roll center a bit more. The next morning in practice and in Q4 the car was the best it had been for us. Joe was still running the set-up we came from and he was happy with that, and it's what he would stick with the rest of the weekend. Now it was Mason and I developing this new direction we were heading.

For Q5 I tried a shorter rear link and I liked how it changed directions quicker but my macro theme was it was still dumping to hard on the front corner when steering, but I did get my best qualifying result in 4th. We tried a few more things for Q6 but it just wasn't any better, but I did get another solid run in 5th. We got lucky as they allowed some more open practice after qualifying was over and we kept at it with the changes. The one that helped the most was doing max sweep back of the front A and B block (A out and B in). This is the first thing that really seemed to help support the front end a bit better in these high speed corners.

Now throughout the event we also learned to cut two rows off the outside and one row off the inside of the rear tires to help it to catch less. We also started to glue the sidewall of the front tires to make it less aggressive on the steering. All of this and we started to put in some mid 17 second laps and we were getting close to on pace as main day approached.
Joe, Mason, and I all made it into the A-main with me qualifying 5th while Joe and Mason were 7th and 8th respectively. In A1 my car was feeling great! I absolutely got the jump on Cav in 4th on the start and was right on his bumper. Over the first double section he and Broc collided and I snuck by into 3rd. I wasn't able to keep pace with Maifield and Rivkin, but I held my own in the position and came home in 3rd! In A2 I quickly moved into 4th and had a great race with Cav. I got by him in the middle of the race and held 3rd for a lap but I got nervous being in that position and I pushed out in a few corners allowing him to get back by and Broc as well at the end. I had to settle for a 5th in A2. To end the day we had A3 and again Cav and I were tight battling for 3rd as Broc made a mistake early again. Suddenly a few laps in Cav's car locked up in the corner before the double and I snuck under into 3rd. I wasn't driving as good in this one as the realization that I could actually podium was becoming possible. Wernimont started to catch me and got within a second for the last 2 minutes or so. But I was able to hold him off and cross the line in 3rd to take the overall 3rd place on the podium!

This was such a huge result for Tekno on their first big event with the new buggy. We struggled at the start but I would say that is to be expected on such a tough surface to set-up for and our limited or non existent practice on a similar surface. We worked awesome together as a team to develop the set-up and while we ended with 3 different set-ups at the end (Mason and I were pretty close, and we were hoping to each try each others cars at the end to compare but there wasn't time.) we were all able to get the same lap times and feel confident with the set-ups we had.

There was for sure things we didn't have access to that could have helped us at this event and could have been used to drastically change our set-up. For instance we really were wanting more support for the front end and felt we could use a stiffer front spring. But we were already using the stiffest they have at this time and so our set-up had to get tailored around that. Also a lighter body and perhaps lower profile body would have also helped to lower the CG. It seems based on this event that for such high grip Carpet you want a bit heavier of a car with as much flex as you can put into it and the lowest CG of weight as you can get. Perhaps if we had a stiffer front spring we wouldn't have needed to add weight to the rear? It's hard to say right now an only more track time is going to allow us to answer such questions. But for this one event we worked together great and came away with great results for our first big event with the Tekno EB410!

Lutzinator

Addition/ Notes:

• To gain more flex in the car we loosened all the chassis screws except the motor mount and bulkheads. We didn't run the rear chassis braces. We loosened all non-critical upper screws as well. (Please only do this at your own discretion. It can cause more car damage on hard hits)

• We felt it beneficial to 're-bleed' the shocks between every run. Basically we would just prop up the car, remove bleeder screw, push arm up slowly and reinsert bleeder screw. No
  oil should come out but it keeps the shocks at the same pressurization for each run. (1/10th is just a little more sensitive ya know!)

• Ran a Tekin RSX with Redline Gen 3 5.5 motor. I had stock timing on the motor but 5 boost and 20 turbo in the speedo for this larger 1/10th track. Also ran around 45 drag brake!

• Please note that many of the set-up changes we did with adding rear weight and such aren't going to be necessary for stock and 13.5 classes. Matt Wolter's car was pretty dialed in the 13.5 class and he wasn't running the weight. But at the speeds us Mod guys are running and trying to compete against the top guys who are just ballistic, it's just what we needed to do this weekend!

R. Lutz

Source: R. Lutz