Reduced to clear FF-03 CR-Z

[alvinlwh 6866]

1 hour ago, Pylon80 said:

You could experiment with that if you have the fancy suspension mounts for it!

Nothing fancy, just going to use M3 spacers under the suspension holders. The proper spacers are sold out everywhere. 

[alvinlwh 6866]

@Pylon80feel free to correct me if I am barking up the wrong tree...will raising the suspension block raise the pivot point allowing the arms to drop further?

A terrible drawing of what I was thinking. 

Apologies in advance for the poor handwriting. 

[Pylon80 3316]

Let me put on my monocle... 🧐... Here. I see what you mean. It depends what is currently limiting your ride height. If it's the amount of droop left and you know you want at least some droop (you do indeed!) then you have to lower the down stops as much as possible. Then to do that you have to check if you are limited by the droop screws or by the shock lengths themselves. If it's the screws then you can remove them altogether. Then, if you are still limited (I think you are modding the FF03 for rallying) you should attempt to increase your shock length. Either unscrew the bottoms or build them with longer rods. If all of that still won't do, then you are correct that raising the suspension pins with a shim will indeed lower your down stops! Just bear in mind that raising the suspension pins will raise the roll center, which will make the car roll more aggressively (not a bad trait on a rally car actually).

Let us know how it drives 😀 I really wanted to do the same with the Civic type R but by the time I was ready it was thoroughly unavailable 🙄

[Verskis 345]

Actually, raising the roll center makes the car less prone to body roll.

[Pylon80 3316]

35 minutes ago, Verskis said:

Actually, raising the roll center makes the car less prone to body roll.

Absolutely correct 👍 sorry about that.

[alvinlwh 6866]

@Pylon80 finally got the time to put on my bifocals 🥸 and properly reply to you.

1. Down stops? I don't think there is down stops on this chassis or am I mistaken again? 

2. Droop screws are currently set at 2mm, as per the stock instructions. So there is room there and it can probably gain me an extra 4mm ride height if I removed them. 

3. Shocks, I already have plans to replace the stock ones with 62 or even 65mm ones. I had seen somewhere 65mm is the correct one but I will leave the measurements till I got to that point in the build. 

Now waiting for a delivery of better suspension pin balls before ordering more bits (had made the mistake of making multiple orders of same item before). They should be delivered tomorrow and I can order more bits to experiment with raising the ride height. 

Yesterday I had swapped the rear spacer around to give the rear anti-squat, which may or may not do anything like you said. 

[Pylon80 3316]

3 hours ago, alvinlwh said:

@Pylon80 finally got the time to put on my bifocals 🥸 and properly reply to you.

1. Down stops? I don't think there is down stops on this chassis or am I mistaken again? 

2. Droop screws are currently set at 2mm, as per the stock instructions. So there is room there and it can probably gain me an extra 4mm ride height if I removed them. 

3. Shocks, I already have plans to replace the stock ones with 62 or even 65mm ones. I had seen somewhere 65mm is the correct one but I will leave the measurements till I got to that point in the build. 

Now waiting for a delivery of better suspension pin balls before ordering more bits (had made the mistake of making multiple orders of same item before). They should be delivered tomorrow and I can order more bits to experiment with raising the ride height. 

Yesterday I had swapped the rear spacer around to give the rear anti-squat, which may or may not do anything like you said. 

Haha I like these bifocals!

1- sorry, "downstop" is Hudy's jargon for the lowest point the arms can go. He makes a distinction with droop as droop is sort of measured relative to the ride height once the setup is all done while the downstops are the absolute distance that the arms will drop to... But it doesn't matter, I simply meant "lowest point".

2- the instructions value is to help to builder get a starting point but the whole point of droop screws is to set things ultra precisely especially left vs right when the screws would be fine tuned. So in your case (rally mod) you will most likely want to unscrew them a lot more or even remove them and let the shocks dictate droop. This is how modern buggies or even the XV-02 works actually (no droop screws!) so nothing wrong with that

3- you'll figure it out later indeed, per my earlier post you can set the car on blocks and measure the ideal eye to eye distance. The limiting factor is going to be either some binding in the C hubs or knuckles or arms (you can trim off some plastic) then the universals. At that point if you remove the pinion you can rotate the whole transmission by hand and gradually set the car higher until you feel a clicking or binding in the universals; that's when you will have reached the limit.

[alvinlwh 6866]

Got quite a delivery today of gearbox related parts. So I had to remove all the stock parts I had fitted to mark the body posts in order to properly get on with the build. 

A lot had been done today and I will probably break this in to 2 or 3 posts. 

First up, the diff again. I got these reinforced gears and balls after I had built the diff last week. As @Alexei said, the diff has to come apart to go into the gearbox, it is not a problem. 

The stock gearbox is removed from the chassis and weighted. 

And this is the carbon gearbox that the gears are going into. 

I also got the 3R gear set which comes with a light weight shaft. Here are the stock bits that will be replaced. 

To be replaced by the reinforced gear with a lightweight shaft. 

The stock counter gear and shaft will be replaced by 3R stuff too. 

Now this is a very significant weight reduction. An additional advantage of the 3R shaft is the plastic K2 spacer is no longer required. 

The gears are greased with MST black grease. One last view before sealing up. 

Unfortunately, the aluminium replacement for this M6 is no longer possible to find. So with kit part it is then. This is one part that will really benefit from a metal upgrade as it does 2 important jobs, holding the gearbox together and also holding the front upper arms. 

 

And that is the gearbox complete. 

Moving onto the gearbox support frame. I will be using this replacement carbon fiber part from 3R. I decided on CF over aluminium one as I believe the metal  one will be heavier? 

The kit plastic bit. 

CF replacement. 

OK got to sleep now. I am typing gibnish. 

[alvinlwh 6866]

Continuing with the update the next day... 

All the bits assembled together to form the power system. 

I did not weight the motor plate as I already got the heat sink bars thread locked on and do not want to unglue them just to weight the part. 

Next, jumping ahead to the K17 gear holder, I actually did the suspension blocks at this point but that needs a post of it own. So the kit K17 part is known to be a serious weak point of the FF-03. The aluminum upgrade part is impossible to find anywhere as I guess anyone with a FF-03 had bought them all up. 

However the 3R SAK-D332 is said to be a direct replacement except the pin hole needs to be opened up for 2mm dowel pin. The is a little more to this, will be explained later on. 

I have a backup plan of using the kit part if the 3R part will not work by using a metal spur gear reinforcement from YR. 

The theory is the metal will help stabilise the plastic kit part. 

Well, in any event, the kit part is not needed after all as the 3R part works after opening up the pin holes. 

However new spur gears are needed. For some reason, Tamiya's spur screw holes are not exactly the same as most after market ones and attempting to fit them on will damage something or everything. Their screw holes are slightly (0.5mm?) further away to the centre than the rest. Luckily, I have a bag of 3R 48dp gears to play with. Seen here is me checking the fit of a 65T spur with a 26T pinion. It will not work BTW due to the distance. 

After trying out a few more, I settled on 80T/31T for a FDR of 6.71. As I plan to be running rally tyres, I made an allowance for the larger tyres. The 80T spur was the stock gear of the MG Evos I built BTW. 

However due to the slight difference in hole distance as mentioned above, the YR spur plate (sized for Tamiya) cannot be used with the 3R spur holder. With both being metal, something will be damaged if forced. 

[alvinlwh 6866]

Suspension, kick up and ride height. 

Right, trying to tune the suspension system to make it more rally than road car. @Pylon80, get your glasses on, you may want to see this.

First I tried FF +5 and RR +2.

Brilliant, nice amount of kickup. Things feel a little tight due to the shafts going straight into the holder on the stock front setup. Metal suspension blocks with balls definitely needed for this kind of setup. 

This "jack up" of the pivot gave a good droop/down stop which should translate to a healthy ride height. 

However, there will be problems when trying to install the gearbox. The FF will hit the motor plate. 

After a lot of trying with various spacers height, the above is the max possible to jack up FF, +1.5mm. Any more and the gearbox will not fit. 

More concerning, the arms will hit the drive cups with relatively little travel. 

Not really happy with this, I am thinking maybe I will jack up the whole gearbox instead. However that will involve a lot of messing around with spacers, I will leave it until the metal suspension blocks arrive and do them all at once. 

Now the front end is looking a lot nicer and heavier. 

I test fitted the bumper upper bumper plate but it will not work with the fan. Since the carbon fibre plates cannot be found anymore, I may need to cut the kit ones but after I had checked if jacking up the gearbox works or not. 

[alvinlwh 6866]

Finished stickering the body. 

And added the most ridiculous wing from #22015 set to complete that chavvy look. 

Windows tinted all round, including the front! 🤣 

[alvinlwh 6866]

The 1060 arrived and I got it installed for a quick electronics test. 

[Grumpy pants 5170]

Great build, really enjoying it 👍

[alvinlwh 6866]

Received some more bits from AT and this is going to be a long night. To start off easy, I will be changing the rear shock tower with this carbon bit from 3R. 

Doing my usual weigh in... 

Fitted and the rear bulkhead dry fitted to the chassis showing the arms position. I had removed the 1mm spacer to raise them a little BTW. 

Then I inserted 2mm spacers at the screw positions. 

And the result is the arms drop more giving me more ground clearance. 

I fitted the wheels to see what it will look like. 

While the clearance is decent, the camber will need adjusting. 

[alvinlwh 6866]

Next up, the front, and it is a bit of a disaster there. Earlier on I said the arms will hit the drive cups, and the right one did when I tested the motor. There was a burning smell and this is the result. 

I am tempted to order another set of the YR diff since they cost just USD5 but RCM wants twice that for postage and then VAT. I am tempted to get the Tamiya item from elsewhere instead but I wanted to see if the damaged part will still work.  The undamaged left side shows how little room there is. 

Removing the gearbox allows me to see clearly what is the damage. 

I will be using these universals from 3R, talk about excessive packaging! 3 items for one pair! 

And I will be using carbon parts for the C-hubs and steering knuckles. 

Starting with the usual weigh in. 

Wow! Take a guess which is kit and which is hopup! The hopup part is actually the heavier one! 🤔

They are not exactly the same as the hopup actually offers no adjustment to the steering (not that I ever used them before). They are otherwise dimensionally the same. 

C-hubs next. 

The hopup is heavier again? However this time the parts are exactly the same down to the moulded numbers. 

In an effort to prevent the alarms from hitting the drive cups, I used wider suspension holders to push them out. 

First I swapped the FT blocks to give me 1D instead of 1XD. Then I got the widest kit part to replace the FF from 1XD to 1B.

This resulted in a lot more upwards movement. (sorry about the focus) 

I am still deciding which length of aluminium replacement to get for the front. I also will be raising them up by 2mm like I did in the rear and this will mean the whole gearbox will have to be jacked up and I need spacers for that. And I ran out of spacers! 

[alvinlwh 6866]

Ii had fitted the wheels so that I can check what the movements are really like. I do have concerns that if I moved things up too much, the damaged drive cup will not hold the universal. It seems to be OK at the moment. 

The wheels I maybe using on this are aluminium wheels from Aliexpress with semi rally tyres. They are quite cool liking and rather  cheap. As can be seen, they are a little bigger than the kit ones. 

Bigger tyres and pushed up arms meant I have to check if the body(s) will still work. 

The cheap Focus body fits even better. 

OK got to sleep not, I am starting to type gibbish now... 

[alvinlwh 6866]

Planned to do up the suspension to see how much I can get out of them, especially the fronts.

Managed to find shocks of suitable length in my spares so it should just be the simple task of doing up the drop links for the Ifs right? Well, those turnbuckles are painful! 

Starting off easy with the rear first, I found some HPI shocks that can be done to 60mm. So I got them on to see the fit. 

That is quite good, looks like raising the rear bulkhead gave good results. 

Now the fronts. Because of the drop arms, I can actually use 50mm suspension here. Just need to length the arms to suit. After playing it by eye, I adjusted them to 15mm instead of the stock 12.5mm.

Still is not impressive. In fact the car sits very nose down. 

Other points of note is the front is so heavy that I had to put the stiffest spring in with a massive amount of preload. If not it will be dragging it's nose on the ground. Plan is to raise the suspension holders like the rear, but I am awaiting the delivery of spacers, and had ordered another 1D suspension holder today. 

So here is how it is at the moment until the next delivery.

Easy morning? It was not! 

While I can put in the steering arm and take it for a test drive, I decided not to as I have the aluminium steering set coming in. 

[guggles 221]

Looks like the biggest obstacle to over come is traction for a fwd rally car. I think once it get moving it should be quite interesting and fun to drive. 

[alvinlwh 6866]

19 hours ago, guggles said:

Looks like the biggest obstacle to over come is traction for a fwd rally car. I think once it get moving it should be quite interesting and fun to drive. 

Which is why, at this moment, I am avoiding any cuts or irreversible modifications, so that I can revert it to a road only car if I don't like it.