Nerobro

iTrader: (2)

Of course. The springs that came with the car, peg the suspension at it's lower limits. limit screws or not.

It'll be ok, I have sets of tamiya springs, I can put reasonable rate springs on there.

Now.. my goal for this car, is to run USGT, in the FWD, no weight limit rules hole. I'm considering bonding some of the ABS parts, so i can lose a few screws. By gluing the rear bulkhead to the bulkhead brace, and shock mount, I could knock off 18 screws. That's 15 grams... There's not much to lose up front though. So I'm going to need to actually invest in aluminum turnbuckles and screws.

fyrstormer

iTrader: (1)

That's strange. The suspension on mine isn't pegged even with the limit screws loosened. Possibly a dumb question: Have you checked the suspension movement with a full-size battery installed?

Don't forget you can adjust the leverage of the front shocks by changing the spacers under the pivot-balls, similar to how you can adjust the leverage of the rear shocks by leaning them over more.

It occurs to me my experience may have been different because I got the FF-03R instead of the normal FF-03.

Nerobro

iTrader: (2)

Everything I've done so far, is with a full sized hard case LiPo installed.

There's a good chance you're looking at FF-03r versus FF-03 differences.

and I just discovered that Tamiya makes carbon injected ~everything For the chassis... and they claim it's lighter.

4roller

Yup, I just placed an order for a crZ bodied ff03. It's coming probably this week.

Yet another chassis to add to the mix.

Fyrstormer, nice to see you.

I too have aspirations to get this car as light as possible. But more so to get a feel for how a fwd car works. I really enjoy my stock ta05. I would like to see how good the stock ff03 will be. I already have thoughts on getting the gear diff, but then again if built and maintained right, the ball diff should be good.

fyrstormer

iTrader: (1)

Lightening the car in the front will hit a point of diminishing returns as the tires lose traction more easily. Remember the front wheels have to do *all* the work on a FWD vehicle.

Nerobro

iTrader: (2)

Oh, some "real numbers" for you. The car, without body, with everything installed, is 970g. Bare chassis, built to spec, no motor, no wheels, is 550g.

I've got a Carbon injected Chassis, Carbon injected front suspension mount parts, carbon injected rear assembly, and an aluminum input shaft coming. Tamiya claims the carbon injected stuff is lighter.

I'm going to pursue my "glue the rear end together" path. That can eliminate 15 grams of screws. And if you've got a fixed length you're going to run the car at, you can drill out, or remove a lot of supporting material that will only work with the shorter wheelbase setups.

Saving weight up front, is possible too. If you're using the forward body mounts, you can trim off the back end of the non drive side motor pod brace, and there's some of the motor mount plate that can be removed. If you're indoors, running without the motor cover is kosher. The front bumper support can be trimmed back a lot. The carbon replacement bits don't even cross the middle, so that whole center section could go.

Other places to save weight: Small steering servo, smaller battery, decase the reciever, ESC, trim off the unused ball heads in the swingarms.

The model comes with steel turnbuckles. Those can be replaced with aluminum.

Each screw you replace with aluminum, saves around half a gram.

If you're serious about low weight, you should also consider the body, there are lightweight bodies out there, and that's "high" weight. For the very light stuff, also consider putting in bumper and side supports so they flap less...

The stock springs are silly stiff. I ended up with yellow and red springs through "bench testing" The stock silver springs are hilariously stiff.

Oh yeah, while we're at it: http://site.petitrc.com/reglages/tam...amiyaFF03.html If you compare the stock setup, to what's listed there, the "factory" shock setup, is waaaay stiff. Those people all seem to be running 3hole pistons, and the manual says 1 hole.

4roller

Thanks for these observations. I always thought trimming plastic pieces that served no structural support to be okay.

As for removing the ability to disassemble the rear end I might just keep it the way it is. Though I don't have the model yet, but I have read it is unnecessary complicated due to the adjustable wheelbase.

These numbers are really low considering my xv-01 comes in close to 200g heavier than my tb03. So these FwD chassis will be extremely light. I guess you loose a little bit of the corner exiting rip compared to a 4wd, but you gain it back in terms of weight savings. We shall see.

With respect to the wheelbase adjustability, 257mm is the standard Touring Car size, but what are the other sizes? Any specific bodies?

You mentioned red and yellows, which are the front and rear? Yellows up front?

wtcc

iTrader: (2)

That is a stunning number
And I thought my FF03 conversion was lightweight. But RTR in comes at 1080g.
Respect! Do you have a picture of your chassis. I want to see where I can improve.

fyrstormer

iTrader: (1)

Now that you mention it, I don't actually remember if I have the stock springs on my FF-03R. I have blue-stripe springs on the front and yellow-stripe springs on the rear.

Nerobro

iTrader: (2)

Ok, here we go:





971.2 grams. That should answer "where I put the springs" too.

So.... the tamiya hard plastic, is not ABS. So acetone won't bond the rear suspension bits together. I think that may need to be an epoxy job, and that's gonna need some good surface prep. Still, eliminating a lot of screws is going to make that happen.


Just to be clear, I'm not going to glue the suspension mounts or the "complete rear end" to the chassis, so I will still be able to use the different toe blocks.

Oh yes, if you were wondering what the stock wheels and tires weigh:



So right about 110g. I don't know what the USGT wheels weigh, so if you do... we could do a little math and get closer to race weight.

wtcc

iTrader: (2)

Thanks Nerobro for this detailed answer!



The Volante Indoor tires are about 110g also.
I am really glad your car is not lighter than mine I thought you were measuring with battery and was excited how you managed to shave off that much weight. The change from the original tub to the cfk chassis saved almost 200g of weight.
Maybe if you use of 1/12 scale 2s shorty Lipos you can put your electronics in-line, maybe also remove material from the tub sides...

Nerobro

iTrader: (2)

We'll see how far I can go. That's with the gear cover and all the screws in place. And without the hard chassis bits. The only weight savings I have there are a lack of battery strap, and no radio or servo tray.

We'll see what happens then.

Speaking of which, what should I use to glue the new, hard, bits together? I'm thinking epoxy with some fiber filler.

What battery do you run? I was thinking about a shorty pack, or a super shorty. The 2650mah pack I run in my buggy pushes a 17.5 motor with ease. I wonder if it would hold up to a 8 minute main...

At nearly $40 a tub, i'm not so fond of the idea of cutting off the sides of my new fancy carbon reinforced tub. We'll see how light the car gets before I get to that point. I can also remove a few grams of material from inside the rear suspension tower. This car will never be converted to a short wheelbase car, so that means I can get rid of some screw mounting bosses, and the associated support material.

wtcc

iTrader: (2)

I am using a 1/12 size 2s shorty from Muchmore with 3300mAh. That is enough to go flat out with a 10.5t for five minutes. The new generation has 4000mAh:
https://www.tonisport.de/marken/much...rd-case?c=5244

That should be more than enough.

Nerobro

iTrader: (2)

I think i'm going to give the 2650 a run, because I have it in stock. If that's not enough, I'll go the 4000-4400mah size.

Sadly, we're looking at another 2 weeks or so before this thing gets completed. Due to shipping from china and all that. In the meantime, I plan on participating in my first race or two :-)

fyrstormer

iTrader: (1)

I'm pretty sure Tamiya's TRF-grade plastic is nylon. Thank goodness they didn't use ABS on this car. ABS always cracks eventually, no matter how gentle you are with it. That was one of the biggest problems with their older cars.

If you're going to use epoxy, you might as well use aluminum screws instead. You probably won't be able to apply the epoxy in a small-enough quantity to save more weight than aluminum screws will save.