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BitHed
05-16-2005, 01:18 AM
...I have lightened my H8 considerably...I am running at 650 grams...This is my set up...

...3Racing carbon front plate, titanium torque rods, turnbuckles and shafts throughtout...KYOSHO titanium slipper shaft, PanicToys Titty Screws throughout, the only NON-titty screws are the size 2 self-tapping screws in the bottom and the gear boxes etc...

...Mamba 25 esc fueling an AON 4900 with a 12t on a 3Racing alloy mount, PanicToys bearings in the center gear box, fixed slipper ie locked...cut rear wing for lower profile and angled up...CAW towers front and rear, FiveStars carbon hinge plates front and rear, stock rims...

...KYOSHO H8 dampers with soft RED springs...front oil is 400 and rear is 300...pistons are 3 hole front and rear i think...

...previous heat issues are now GONE...I am using a funky red 300 size GWS sink from time to time...

...The problem NOW is that I can see and feel that I am losing traction at high speed....I am almost hydro-planing...It looks and feels like I am skimming across the surface of the road, only on-road so far with the AON...

...I set up my shocks when i was wearing the 1:10 HPI rims which were 26 mm...I will switch back to them tonight to see if i cant keep them on the ground a little more...

...What do i have to do to keep my traaction? Its not like i can 'soften ' the suspension much more...I COULD go a lower oil, that would be 300 in the front and 200 in the rear...Harder springs would defeat the purpose...I might take the spacers out of the shox when i redo the oils...hmm...Maybe i have made it TOO light?

...If you can read through ALL of this and have an opinon then please let me know...BitHed Thanks You...

TNB
05-16-2005, 02:42 AM
...Maybe i have made it TOO light?
Some people I know actually add weight to the rear end of Kyosho Mini-Zs to help maintain traction when running hot motors. Sometimes I think a little weight is also better to help prevent too much bouncing off-road. However, I've been running on an 1/8th scale track. For several photos of the track, visit the "Local Off-Road Track" album in Gallery TNB at MiniZRacer. It was also 100F when I got home today, so I know it was even hotter at the track today.

http://www2.mini-zracer.com/gallery/album667

rstnboy
05-16-2005, 03:24 AM
650 grams?!?! Very nice! I agree with TNB...you may have too much of a good thing in the weight loss department. You could try adding a couple of lead wheel weights somewhere on the chassis and take it for a spin to see of the handling changes for the better.

Where did you find the softer springs? I would like the chassis to sit lower without having to use the ride height adjusting screws to force it lower. Softer springs would definitely help in this area.

BitHed
05-16-2005, 04:02 AM
...halfeight option spring set...34 USD shipped...one going on ebay this afternoon unless someones beats me up for it before hand ;)

BitHed
05-16-2005, 04:17 AM
...i have the C rear shaft plate in and droop screws getting me down lower too...maybe I should pop it back UP again? And if i lower the oil weight, take out the spacers, it should sit a little lower, therefore have more 'stick' ?

WhoMe
05-16-2005, 04:43 AM
Make sure your arms are level..that should be low enough. Also make sure your treads are good to go. But if you are running on the road only..throw some tenth scale foam tires on the sucker; put some traction compound on them and she will handle like a touring car. lol

Trax
05-16-2005, 06:49 AM
I was wondering if you would ever go brushless Bithead :) .How is the AON 4900 working out? I have read a good review of the 3500 at trextuning but haven't heard anything about the 4900. Time to switch over to li-po's next..... :)

BitHed
05-16-2005, 06:55 AM
...yes i took the plunge and went brushless...I was given an opportunity to participate in the AON program that the owner Steve Chao presented to us...I am a very PROUD owner of an AON 4900...

...it is JUST 4900 but i can now believe all these people who are selling their Mamba 6800's LOL...These brushless things are pretty quick eh...

...my NEXT brushless will ALSO be by AON ;)

OneTimeCRX
05-16-2005, 10:20 PM
Bit, reducing the mass won't reduce your cornering abilities on the road - the downward force on the tyres is reduced (which reduces the max friction of the tyres), but also the rotational inertia of the car is reduced an equal amount which exactly cancels out the effect of less friction.

Actually what you're probably seeing are one or two effects:

1. A lighter car will drive at higher speeds for a given amount of motor power, and at higher speeds the car will drift more.

2. The lighter a car is, the more dependent it is on aerodynamics. Especially with such a large wing in the rear, such cars tend to have an imbalance in downforce front-to-rear for on-road use.

Adding weight to the car will mitigate both these effects, but you'll end up with a slower accelerating car (and most likely slightl slower too). What I suggest is that you work on the aerodynamics. I've tested my 1/10 touring car in our wind tunnel, and found that there was a large downforce in the rear and a slightly smaller lift force in the front. This explained to me immediately the constant understeer problems I was having at high speeds. After removing the rear wing and adding a splitter in the front the car is now much better at high speed.

For on-road use, the center of gravity (CoG) height also plays a huge role in handling. By using the droop screws to lower the car you'll get higher cornering abilities.

By "hydro-planing" I interpret this to mean that you're getting too much understeer. This can be reduced by adding a sway bar to the rear suspension. What a sway bar does is increase the weight transfer between the left and right wheels. The quicker the weight is transferred to the outer wheel, the sooner it'll reach its max friction abilities. Once past this point, the wheel will start to slide out. Therefore adding a rear sway bar will cause the rear to loose traction more easily, which will counteract understeer.

Also think about the friction circle (it's shaped more like an egg actually) - a wheel can only provide a certain amount of frictional force in any direction. For example the more a wheel is used for acceleration, the less it can be used for cornering. Therefore if you're on the throttle hard you'll reduce the car's ability to corner. By easing off the throttle you should see the car corner much better.

jatetu
05-17-2005, 11:02 PM
onetime, it's a pleasure to hear an expert. You would be a great teacher. I have understood everything you told (i think).

great!! :)

OneTimeCRX
05-18-2005, 09:48 AM
Thanks Jatetu! BTW, I do teach courses for the automotive engineering masters programme at a university in Sweden. :)

halfEIGHT
05-21-2005, 03:52 PM
:eek: Ah! That explains a lot! Cool! :)