Sunday, July 31, 2011

F104X1 First day on asphalt

I got a chance to run my car on asphalt for the first time today.  My initial thought was that it actually understeered a bit.  This may have been due to the tire treatment.  I was trying to actually use an oil type  additive, but after the warmers came off, I re cleaned the tire with buggy grip.  This seemed to clear up a lot of the issue with the tires feeling "greasy".  The car actually was fairly locked down.

I was also using 28g of weight on and around the servo.  This is an idea based on the new 1/12 layouts using the battery lengthwise in the car to get more weight in the nose area to promote more on power steering and a bit less twitchyness.  It's like putting a case of water in the front of a shopping cart.  It doesn't change directions so fast, but it goes once you are committed.

Anyway, I started to increase the angle of the upper arm by lowering it at the inside by 1mm, and on subsequent runs, raising it at the kingpin by .5mm.  I also went to 2.0 camber.    This made a lot of off power steering, but it didn't turn that hard on the throttle  To help this, I went the yellow spring, from the red. Again, it was helpful, but not a huge difference.  Lowering the shock ballstud by 1mm did get the car steering a little more as well. 

Adding 1mm to the reactive caster (placing the shims under the rear upper arm ballstud) again got the car turning more off power, but didn't help the on power much at all. 

Raising the front ride height 1mm did actually seem to help a bit.  I sort of think the car could roll a bit faster with the nose up.  I'm not sure about this, so I'm going to have to try it a little more.  It did seem promising.

One other thing I did have a chance to try was changing the damper tube.  I started with 5000 diff lube, and went down to 2000.  The car had quite a bit less dampening, and it also had more response.  It was a bit hard to get a really good handle on this, as I had a set of tires starting to go off when I did this, and I went to a newer set on the next run.  I'm tending to think it may be better off to actually run a little stiffer lube when there is less bite to the car is calmer.  Obviously, this only holds true to a point, but 5K to 10K should be ok.  I would say start with 5000 and go from there.

Overall, the car was a little on the push side, but I could drive it fairly hard and not have to worry about it spinning out or acting funny otherwise.  I did identify an on power push, but this car may require a harder spring and or shock oil setup, since the damper disc acted in all directions, vs. the tube which only affects side to side movement.

It was a bit hard to play around with too much more, as the race was a local series race that had around 70 entries.  Track times was a bit of a premium, but I'm going to try to get more practice this week and work through some of the issues.


  1. Hey Rob,

    Nice write-up/review on the X1. I've been pondering with setup ideas since I built mine. I agree the thicker grease on the roll damper helps settle the car down. I haven’t tried the reactive caster yet that’s next. My big question is how do you think the “soft T-plate” would work? My thought is since the car gets better with thicker grease on the roll damper, couldn’t you change to a stiffer T-plate and softer roll damper grease? What you do you think?

    Thanks for your time,

  2. Vyger first off I would say you will lose some rotation by going to the "soft" t plate over the "hi traction". The car doesn't twist as much with the "soft" plate.

    That being said, if you are on a track that is more sweeping turns than 180's (think Tamiya USA), that might be a plan. The RtypeC video looked like he wound up with a bit of understeer at the end of the day, so that might be a way to cure it, as long as the rear is still hooked up.

  3. what body set are you using on this X1?

  4. Sorry for my english..
    I'm from Brazil and i'm just bought one F104x1. Now I need a Lipo and I've a question, what's the size of lipo that you use in the F104x1?
    Thanks for helping, people here used to run F103 but nowadays thei onli race with GP touring cars..

  5. Hi
    The best lipo to use are the ones with the rounded cases, like the Orion Rocket packs for example. You can fit the rectangle case pack, but you may need to grind the radio trays.

    Also, you can use a pretty low capacity pack. A 3200 mAh pack is more than enough. I have used 1800 mAh packs in 8 minute races with success.