jeff jenkins

iTrader: (82)

Remember he drives a poo-mocker cxl so they are prone to traction rolls.

grippgoat

iTrader: (8)

Hrm. So I should probably measure at the rear of the tire where it's widest.

1) Because Brett's doing it, and kicking my ass.
2) Because I've never tried it.

And this.

Didn't think of that.

And this. Although since I've only be saucing half front, not so much. But I've also been having understeer and having to scrub more speed on corner entry, which I think might be what's holding me back a bit.

Lowering the front shocks one hole helped, but made it less responsive, so I tend to be too wide on entry, although it did give me the mid-corner grip to bring it back to a late apex. That change made my runs more consistent, but I still end up using too much track on most laps.

Strangely, I didn't have traction roll issues (maybe just a hair in warmup) at the Can-Am challenge. But this past weekend, with fewer people which should mean less grip, the car seemed a bit tippier, like I couldn't push until about 2 minutes in. I'm wondering if the sauce is the difference. This past weekend, I ran SXT, but the 3-4 races before that I ran Jack the Gripper, and seemed to have really good consistent tire performance. Maybe Jack is just better? Or maybe my tires are getting old. The only setup difference was 1mm spacers against the rear hexes.

I did manage my first 27-lapper in Q1, but it wasn't as good as the two 27-lappers I threw away at the Can-Am challenge. I also managed a new personal best 13.370 lap time in the main, but that was still 4/10 off the fastest lap, which is about how far back I've been for the last few races now. Still better than the 1 second off I was last year, so I must be doing something right.

Here's another question. Right now, my car is pretty rear-heavy. I think the weights are about 310-315 per front tire, and 330-335 per rear tire. I have two ways I can move weight forward. 1) Move the battery to the forward position, which will give me just about exactly 50/50 front/rear. Or 2) move the arms backwards, which will probably be a smaller change, and will mess with the steering geometry. Any thoughts? I feel like it's probably better to leave the steering geometry alone for now.

-Mike

jeff jenkins

iTrader: (82)

You could just shift your entire chassis forward by say moving the same amount of arm spacers from in front of the arms to behind the arm . Doing this to the front and the rear arms the same amount effectively shifts the chassis forward and keeping the same total wheelbase.

jeff jenkins

iTrader: (82)

Also remember that Brett used to be a factory driver in the tc3 days and even if you do the same stuff most likely he will still be kicking your ass! Lol

malkiy

iTrader: (10)

I thought last Saturday had a lot more grip than the can-am. I ended up traction rolling twice in the main.

I was experimenting with tire prep too. Wanted to apply a little of what I learned in 1/12. In 1/12 they tend to sauce full fronts and turn down the dual rate. The reason being is that full steering throw scrubs speed. I tried the same on my touring car, full fronts (normally 3/4) and turned my dual rate from 115 to 80. I had the same amount of steering but had a little more corner speed. The car seemed to handle more consistent too, the front end no longer want to dig in and pivot.

You might want to shift some weight forward. Think it could smooth your steering out.

Have you tried wide front track and narrow rear track? That always helped with my past traction rolls. Space the arms out rather than the wheels.

malkiy

iTrader: (10)

Brett finished just behind Travis when he won the ROAR nationals in California. Brett has also won the Tamiya nationals.

Maybell

iTrader: (2)

I wanted to take a moment to thank everyone for the incredible support of the Tub! You guys are awesome!

Happy Holidays and a Merry Christmas to all!

cementsurfer86

+1.
I was watching most of the Mains and it seemed like traction was insane for everyone.

grippgoat

iTrader: (8)

That's what I meant by #2. But doing that will mess with the steering geometry. With the single-crank steering, I can't just remove ackerman spacers and get the same steering, because it'll change the arc. I don't want to mix changes yet.

Yeah, I'm definitely remembering that. But my fast lap is a pretty good indication of the potential of the car. When I had Korey drive my car for a night, he only had a fast lap of 13.4, compared to my previous 13.6, and was really caning the car to do that. Of course, the setup was out in the weeds at that point.

Since then, I've made some tweaks and have consistently had fast laps in the 13.4s for the last 4-5 races. Mike, Jeff, Brett, Andrew, and Sam are have fast laps that are .2-.4 better, and their consistency is .2-.3 between fast and average, where mine is .4-.5 most of the time. I'm pretty convinced that there's at least half a lap in setup changes. It might come from doing more 13.4's and 13.5's in a run, or having a similar consistency with all my laps a few tenths faster. Either way would be a step forward.

I've been turning dual rate down to about 85% for quite a while. I found that if I used full steering travel, I'd just be inducing push which in lower grip would make it harder to drive consistently, and in higher grip would just make me roll. 85% seems to be the point where I just crank the steering, and if the car doesn't turn, it's because I tried to go in too fast.

I actually experimented a bit with going up to about 90% dual rate with the LTC-R earlier in the evening, and it worked when grip was lower, but by round 2 I felt like using that much throw was just courting traction roll.

That's what I'm thinking. I tried battery forward at the beginning of the year, but it felt funky and I was more consistent with it back, which is why I stuck with that. But I never made a serious attempt to tune the car for the forward weight. My thinking is that balancing the weight front to rear better might help the traction roll, too.

The setup I've been running has a wider front than rear. Kit stock uses 1.5mm spacers at the front hinge pins with wider hexes. The standard (literally everyone uses it) setup has 2.5mm on the front hinge pins with 1mm narrow hexes. That gives ~188mm front width. With the narrower front hex, the distance from kingpin to wheel is the same as Xray T3 knuckles.

The kit rear setting, which I've been running, is 1mm at the hinge pins, which gives a track width that's about 2mm narrower per side at the axle than the front. The Hofer setup (all the team drivers run it) is .5mm spacers at the hinge pins, with a .5mm spacer on the hex, giving the same width with narrow pins than the front. I haven't tried that yet, because I didn't have .5mm wheel hex spacers. This past race I tried the same setup I've been running, with 1mm on the rear hex, and I feel like it gave me a bit more steering overall.

Brett's setup is wildly different, running lots of ackerman spacers, front arm sweep, and much wider rear hinge pins, and 50/50 weight distribution (achieved by putting the battery half way between forward and back positions, and moving the arms back). So that's the direction I was thinking I'd move in. But I don't think I want to try the ackerman and arm sweep just yet.

Another difference that does occur to me when considering moving the battery vs. moving the arms, is that if I move the arms back, it effectively moves the body forward, which will give more front downforce?

-Mike

malkiy

iTrader: (10)

I'm running lots of Ackerman spacers and arm sweep too. I would think it would help with traction rolling. Arm sweep gives less in / more steering mid turn and more Ackerman spacers would smooth the steering out.

grippgoat

iTrader: (8)

Hrm, I didn't realize you're running arm sweep. With my current setup, if anything I want more initial, which is why I haven't tried the sweep yet. I haven't tried a shorter wheel base yet, either. Paul Lemieux actually suggested in his thread that most people who like sweep would be just as happy with shorter wheelbase without the sweep.

There is much to learn.

-Mike

malkiy

iTrader: (10)

I'm running super short wheelbase too. Currently running 256mm. This and a thinner, more flexible, chassis were the biggest improvements to my car.

malkiy

iTrader: (10)

I would copy everything Brett is doing to his car. He is one of the more knowledgable racers at the track. If anyone can get full potential out of that car it would be Brett. Maybe use his setup as a baseline then tweak it.

waswadener

iTrader: (72)

Questions RE Mod Touring:

1. Would a Tekin RS Pro be capable of relaiably powering an un-boosted 3.5t motor?

2. I have a spare Novak Ballistic 17.5t motor. To turn it into a 3.5t motor, all I would need to do is install a 3.5t stator, yes?

I ask because I've been toying with the idea of trying mod touring just for kicks but, to do so, I'd rather use my existing components than buy more stuff.

Bill S.

jeff jenkins

iTrader: (82)

the rs pro has no motor limit and if it does I think its 2.5t so yes it will work even boosted but trust me you don't need a 3.5 t kody only uses a 5.0t I use a soft 4.5t or a 5.5t . But you will only need a stator. Last weekend I was running in the main
Steve currys greedy sonic 4.5t and running at a 8.7 FDR with a Novak gtb esc.