BigDogRacing

iTrader: (12)

Thanks Martin, I'm really enjoying your book. My partner and I got it together and I knew quite a bit of it already, but it has really helped me put the pieces of the jigsaw puzzle together if you know what I mean.

Remember the things I was going to try on my Yok SP? Well I did, and they helped. They also did what we expected. I raised the ride height first, which basically reduced the amount of uptravel. I went from 5 to 5.5 which felt a little better and the car was dragging so it needed it anyway.

Next I reduced the shock length of the rear shocks .6mm which probably gave it about 1mm less downtravel. This helped reduce the amount that the rear end is kicking out on corner exit, but didn't stop it totally.

I didn't get my 3 degree front caster blocks yet, so I don't know if they work.

I've been thinking about the problem and I have a few more things I want to try. One is moving the rear camber link to try and get a little more contact patch on the rear tires while the chasis is rolled over, and the other is possibly reducing the front shock oil to let the front rise quicker as I apply throttle mid corner.

One thing I noticed that threw me off a little was that at first, boith cars were still setup the EXACT same as they were the race before with the same tires and everything, but the Mission wanted to push a little more and the Yok wanted to kick the rear around on corner exit a little more. I guess it was an example where a slight reduction in traction amplified the areas that both cars needed work in the traction.

I think a simple move of the rear shock one or two positions out will fix the Mission. It was the fastest car on the track anyway, even with the slight push. And sooo easy to drive, especially the race prior to Sunday.

mcrisp

Hi BigDogRacing,

Glad to hear you are getting good results with the changes. You might want to try more uptravel in the front to reduce the oversteer at corner exit.

By the way, if you want to talk live about your setup, send me an email.

cya,

TRF-Powered

Hi Martin,

I went to your website, and I checked out your 414M set up. I just wonder what are those taps doing on top of the slots where the batter goes? Is it just to prevent the battery shrink wrap being scratched off by the carbon chassis?

Also, do you CA your chassis? If you do, what kinda CA do you use? I used Tamiya CA on my TB EVOII's and 414M chassis, and it eneded up kinda foggy on some part of the chassis. Also, do you only CA the lower deck of the chassis or did you CA all the carbon parts?

One last question is that do you use Aluminum center oneway and pulley? also, do you change the ball diff to aluminum ball diff??

Thanks

mcrisp

Hi TRF-Powered

yeah, I used the tape sometimes on the chassis to prevent a short between the battery and the chassis.

I use the ZAP CA to do the lower deck only.
The ZAP CA is very thin, and flows well. I put it on a Q-TIP first and then run the Q-TIP along the edge of the chassis.

Yes I do use the Aluminum center oneway and pulley. Although it adds weight over the plastic ones, they last a lot longer. I have tried the Aluminum ball diff in the rear, but went back tot he plastic one to save weight.

Hope that helps.

cya,

Alvin

Martin,
Hiya, yet a few more roll axis questions

a. How do you raise the rear roll centre on your 414m? Do you actually attach the camber link onto the shock tower? Or do you add/remove spacers?

b. Tried a roll axis tilted towards the back. Very agressive entry (dual one ways) but tended to understeer out of corner. I.e. I need to take certain lines in order to maximize the agressive turn in. Reduced exit push by using harder shock oil. Any further way to improve the corner exit steering?

Thanks!

~Alvin

mcrisp

Hi Alvin,

a) I raise the roll center both by rasing the lower "A" arm and by lowering the inner pivot point of the upper link. I currently run between 2mm to 3mm of spacers under the hinge pin blocks to raise the lower "A" arm. By the way, I don't know if you have looked at the pictures of Surikan's car from the worlds, but he "appears" to have about 6mm to 8mm of spacers under these hinge pin blocks.

I am also experimenting with using the shock tower versus the bulk heads for the upper link inner pivot point. I can achieve similar roll centers with both the shock tower and bulk head upper link inner pivot points, but when I use the shock tower the link is shorter and thus creates more of a camber change, which can be good depending on what you need. Try both and see what you like. For a long time I used the shock tower, but I just changed back to the bulk heads this week just to experiment.

b) Since I don't know how you have the rest of the adjustments on your car setup, it is difficult to say what you might try. Having said that, if you go with a more horizontal roll axis, this should reduce the push on corner exit as the rear will roll less relative to the front. The agressive corner entry migh actually get worse depending on how the rest of your car is setup. You could consider a stiffer front end or more caster to reduce the agressive initial turn in. Also if you are using a lot of toe-out in the front this could be contributing to the agressive turn-in and potentially understeer on corner exit.

Hope that helps.

cya,

Jack

A) Add or removing the spacers to raise or lower the roll center on the bulkhead
u can attach the link to th shock tower but doing so u actually shorter the link which will result in more camber change
This might or might not be good. depending on what u like
B) i have no idea.

TRF-Powered

Hi Martin,

Thanks for the tips.

By the way, have you tried to put the front sway bar on the upper deck of the chassis? Does it imporve the performance of the car that much?

Thanks in advance for any info!

mcrisp

Hi TRF-Powered,

I have not tried it yet, but another driver at my local track has been trying this setup for a couple of months. He seems to like if for high speed corners.

I think the main reason why Surikan put the sway bar on the upper deck, is that he raised the hinge pin blocks so high that he could not use the plastic holders that normally hold the sway bar in place.

TRF-Powered

Hey, Martin,

Are you coming to Reedy Race this weekend? I heard all the pro driver are coming. Are you?

mcrisp

Hi TRF-Powered

I had made plans to go, but I had to cancel due to some other commitments.

I really wanted to be there.

Are you going?

TRF-Powered

Hi Martin,

Yeah, I will be there, but not to race, just to watch. I was late to register, plus, I don't think I'm good enough to race with the pros/semi-pros. I picked up this hobby since last summer. I haven't had whole lot of time to practice or race due to busy college year.

Hopefully after this summer I can get my skill to a certain level, so I can race more competitively.

By the way, are you coming for this years TCS final? I am going to race in TCS in August for the first time. Hopfully I can finish decent so I can get into the TCS final.

mcrisp

I would like to go to the TCS final and participate in the "past champions" race for fun. Depends on the cost!

ZER01

mcrisp, what about the angles of the front hinge pins in relation to the chassis when viewed from the top of the chassis. In other words like toe-in/out for your hinge pins. Does this make a differance in handling? Losi says "it's just better"(the front are toed out and the rear are toed in on the XXXS touring car)? Man, I sure would like to hear the answer to this one. Thank you for replying to my wheel question.

mcrisp

I asked Todd Hodge who does R&D for Losi this very question at the ROAR carpet nats this year. If I remember correctly he said that this gave the car more corner speed and steering.