3LikesTamiya TRF415
08-16-2007, 09:07 PM
Tech Rookie
08-16-2007, 11:11 PM
Tech Adept
08-17-2007, 01:25 AM
My parts for the mod are on the way, I'll be intrigued as too how much difference it will make. Since I've used ceramic balls and the sanded rings, I've had very smooth diffs (then again, the TRF's are good anyway
).I'll be building the 16ball with ceramics and JAAD racing blue alloy diff halves (leaves the option of using the old diff if needed)... here's hoping I won't have to touch it anytime soon!
Regards
Ed
08-17-2007, 01:56 AM
Tech Adept
Now it`s time to go again. We have race weekend and tonight is free training session and tomorrow race day. I`ll test that new diff and 18t pulley in my MRE, so we`ll see how it goes
Hopefully the weather is mercy in this time
See you guys later...
Hopefully the weather is mercy in this time
See you guys later...
08-17-2007, 03:28 AM
Actually contradiction is a part of engineering
It is something in the lines of "if you want more traction on the front then lower the traction on the rear" kind of deal Sounds like I need more kicking to do
There are so many things that affect the efficiency of our touring cars drive train. Here are just the key ones:
Required Preload (to handle drive train load)
Pulley diameters (belt wrap & tooth count)
Tooth profile (mesh and un-mesh of the teeth)
Material (Aramid or glass fiber and Rubber compounds)
Required Preload (to handle drive train load)
Pulley diameters (belt wrap & tooth count)
Tooth profile (mesh and un-mesh of the teeth)
Material (Aramid or glass fiber and Rubber compounds)
, but if all else is equal then a faulty bearing would have the most affect on the drive train efficiency if all else is equal. so this is irrelevant...well not sure about this one.... yes I agree that I lower the preload on stock a little but not too much. as my stock motors pump out quite alot of low end torque I always need a fair amount of preload even for stock.
actually "in general" part is not necessary. more tension or pressure more resistance or drag...
The main reason we are swithcing from 16 to 18 is first of all changing the IR so we can change the FDR.
Second is more physical reason. As you mentioned earlier materials play a great role in the belts efficiency and its minimum turning radius or wrap. So by increasing the pulley you increase wrap or the truning radius of the belt .
the 18T pulley has more loading capacity by default as it has 1 more teeth to come in contact with the belt wrap. hence if the applied force is the same, the distributed force over the pulley force side is divided in to 9 parts versus 8. now this is for the if force is the same. and it will not be as the IR is changed so the gear ratio will to comapnsate. there fore the forces will change...
Or you can maintain the same preload and increase your load capability. Either way, you get an increase. Think of it like stage diving. You don’t want to stage dive into a crowd of only a couple people. The more people you have to catch you, the less force is applied to each person. This is actually a similar reason the TRF guys make the modifications to the diffs. More on that later.
reason 1: you need the extra teeth so you gane transfer power more reliably
reason 2: larger pulley you can fit more balls to reduce the pressure load on teh balls themselves.
reason 3: the driver can live with the increase surface friction of the larger pulley when compared to the durability of the system.
The material is very important because of the flexing the belt must do. Aramid fiber (aka Kevlar) is a great material but it has good and bad tendencies. It is stronger than glass fiber and heat resistant but it can expand slightly depending on humidity. Glass fiber is not as strong but is very stable. Then there is the rubber compound, softer compound will have less resistance to flex compared to harder compounds. How important is this? It’s why Tamiya Low Friction option belts are low friction, because of the fiber material and softer belt compound. It’s not because it has less surface area (they are all the same width). The softer rubber compounds of course don’t last as long and break down much quicker. The also are a little less efficient at high speed because they begin to flutter more.
so harder and/or stronger the material the larger your pullys have to be. you can lower numbers but you have a life penalty on the belt.
thats why on my fist post I said we need tensioners on the chassis. to reduce flutter
Back to the TRF diff mod, using the 501 diff rings and the outer diff holes puts the diff balls in a better position of leverage over the load they must sustain. This allows a big reduction in diff tension in itself for the same holding force as it would compared to stock. So, less tension, less wear. Adding more diff balls is similar to adding more teeth to the center pulley. The additional balls distribute/share the load which further allow less diff tension for the same holding force (like stage diving). This is why your diff will last much longer and stay more consistent with this diff set-up. Again, this is also why going from a 16 tooth center pulley to an 18 tooth will do one of two things, REDUCE friction/increase efficiency (less preload requirement) or increase load capability if you maintain the same preload.
I am sure we will start seeing direct rear drives or gear diffs soon...
08-17-2007, 08:09 AM
Tech Rookie
So then... Schuey lube for the ring to outdrive (grips more), and AE for the balls? or are you better off just using the same lube throughout, to avoid contamination....
My parts for the mod are on the way, I'll be intrigued as too how much difference it will make. Since I've used ceramic balls and the sanded rings, I've had very smooth diffs (then again, the TRF's are good anyway ).
I'll be building the 16ball with ceramics and JAAD racing blue alloy diff halves (leaves the option of using the old diff if needed)... here's hoping I won't have to touch it anytime soon!
Regards
Ed
My parts for the mod are on the way, I'll be intrigued as too how much difference it will make. Since I've used ceramic balls and the sanded rings, I've had very smooth diffs (then again, the TRF's are good anyway
).I'll be building the 16ball with ceramics and JAAD racing blue alloy diff halves (leaves the option of using the old diff if needed)... here's hoping I won't have to touch it anytime soon!
Regards
Ed
You're going to love the 16 ball diff. If I run mod, I'm lucky to get 5 runs out of my standard diff with carbide balls. The 16 ball diff can go at least 3-4 times longer for me.
Last edited by jinsc; 08-17-2007 at 08:33 AM.
08-17-2007, 08:18 AM
Tech Rookie
BTW, if I'm lacking traction in the front.......I'll increase traction in the front instead of removing rear traction. I think your way of thinking is......uh...unique.
08-17-2007, 04:31 PM
08-17-2007, 04:59 PM
08-17-2007, 07:23 PM
08-18-2007, 08:39 AM
Uh...no it's not. Contradiction is not part of engineering (well at least good engineering). However, compromise is.
BTW, if I'm lacking traction in the front.......I'll increase traction in the front instead of removing rear traction. I think your way of thinking is......uh...unique.
BTW, if I'm lacking traction in the front.......I'll increase traction in the front instead of removing rear traction. I think your way of thinking is......uh...unique.
Everyone has their own way of doing things...
Uniqueness differs us form the rest... If we are not unique then we are just common.....
08-18-2007, 06:20 PM
With this conversion set, stick-type 7.2V battery packs can be installed in the previously released high-performance 2-belt 4WD TRF415MSXX chassis. Set includes 2.5mm carbon fiber lower deck, 2mm carbon fiber upper deck, and carbon fiber battery plate. Specially redesigned lightweight blue anodized aluminum rear bulkhead, rear upper brace, and center post are also included.
*Compatible Chassis: TRF415MSXX
looking at the chassis, looks like it's designed for 4-cell, 6-cell, stick type battery. will the 4800's lipo fit? the bulkhead has been redesigned so that the 6-cells and stick type won't be under the old bulkhead design.
what do you guys think?
08-18-2007, 08:39 PM
I am surprised we dont have at least 1 manufacturer running sealed gear diffs yet. It made a huge difference in onroad nitro. and weigh is unlikely the issue, a compact gear diff could be created.
08-18-2007, 11:07 PM
Weight WAS a big disadvantage then!
08-19-2007, 12:51 AM
1/10 gas cars used to have ball diffs... they are all running gear diffs now.
but weight penatlty as u said would be a problem...
but I can see a future in direct rear and oneway fronts