Xray T4 LCG conversion and more...
 

Inspired from the new T4'18 and its short shock absorbers I thought about a conversion for my T4'17 (originally T4'15) to keep it on pace with other LCG cars like the A800. The upcoming indoor season should favour a lower CG with its high grip surfaces.
As we have already seen, Xray reduced the length of some parts of the absorber, but not of the shock shaft, which causes issues if the absorber is fully compressed. Also the chance that the "old" longer shock will have a comeback for the upcoming 2018 outdoor season by the pro drivers is quite high.
So why not save a little money, use the absorber we have and install them lower... How about 6mm lower (to be better than the T4'18 :lol: ) :smile:

https://abload.de/img/img_78637zstm.jpg

https://abload.de/img/img_78688lszo.jpg

https://abload.de/img/img_78679qsyk.jpg

I have already tested this conversion outdoor and indoor. And it works very nice. Even though the lower shock mounts are 6mm lower they don't make contact with curbs or make any other issues.

https://abload.de/img/img_786908sfk.jpg

https://abload.de/img/img_7873t0sgz.jpg

For the front I recommend buying two servo posts, drill holes in the suspension arms and istall them like that:

https://abload.de/img/img_787251suh.jpg

I really tried to make this a low budget conversion, but of course it will need some material, tools and a little skill...

What I built:
- one front shock tower
- one rear shock tower
- two rear lower shock mounts

Material:
- 2.2mm-3mm thick carbon fiber (depending on what I had/you have laying around) preferably an old chassis plate

Tools:
- a rotary speed tool with different inserts and self centering drills

What to do:
1. Draw the geometry of the graphite parts on the carbon/old chassis plate. Make sure all measurements are as accurate as possible!
2. Put on protective clothes, respiratory protection, safety goggles and gloves. I also use an old hairdryer.
3. Prepare your working space outside. Place the hairdryer in a way that it is between you and the rotary tool and /or arrange everything that the wind blows the dust away from you.
4. Now take a self centering 3mm drill and start to dill all holes first. Make sure you drill slow and with little pressure. You have to be very precise at this stage!
5. Put on the sanding tip and break the edges of the drill holes.
6. Install the diamond disc on the rotary tool and cut out the shape.
7. Sand away excessive material and correct the shape.
8. Clean the part, fit it on the car, if needed optimize the geometry.

Unfortunately there is one downside to this conversion:
The suspension arms have to loose quite a lot material where the spring plate is located to prevent rubbing and to to install them properly. This will not effect the handling or durability in a negative way.

That's it for the moment. Later pictures with part dimensions will follow.

Nice effort wtcc, and it will perform good...
The Awesomatix cg is very low, but my tc4 with low shocktowers and tc7.1 short shocks performed decent enough not to need another set of shorter shocks... I think there is a point where the benefits of lower cg are negligible...Most racers still have to glue the front tires on the Awesomatix the same as the xray t4 17 or tc4(short shocks) to stop traction rolling, and the corner speeds are pretty close....
The only thing I had to do on my tc4 on crc carpet is to put the thickest gold swaybar on with a 60gram ultra lightweight body....

Here now a view of the mentioned parts in their second version:

http://abload.de/img/bildschirmfoto2017-10ugj63.png

There probably is a good reason why nobody does this on 1/10th electeic cars, but why not mount the shock further out on the wishbone. This of course changes the damping but surely this can still be worked out with different springs, oil and piston?

Great work again.

If I can add my opinion in order to have better shock progressiveness do it like 1/8th on-road cars do.

https://cimg8.ibsrv.net/gimg/www.rct...66171f1575.jpg

This is on a 1/10th Serpent nitro car

Red RC ? RC Car News » Serpent Natrix 748 200mm nitro on-road kit

Nice hook that can stick into the carpet or the edge of a curb.....

And is the difference noticeable?

I am not sure if a change of the damper angle would make sense on a proven car like the T4. My conversion just loweres the shocks. Otherwise the geometry stays the same.

The lower mounts will not hook in the carpet, because they are mounted on the arms. So if the arm moves up, the mount will move up, too. I have tested it two full days and one race on an oldschool outdoor track with high curbs, low curbs, bumpy curbs; these "hooks" never even touched the ground once or got stuck. I had the same experience indoor, too. And there I often ran over the curbs and the wooden strips that seperated the lanes, because visited the track for the first time ever.

Indoor it is clearly recognizeable that the car stays flatter and is stressing the front outside tire less. So this mod is save to drive on regular tracks and will not violate the ground clearance rule of 5mm which is mandatory on most tracks ;)


Now for those who want to give it a try, the dimensions of the parts (units are in mm):

https://abload.de/img/bildschirmfoto2017-10e5rtu.png

https://abload.de/img/bildschirmfoto2017-10ocqzu.png

https://abload.de/img/bildschirmfoto2017-10e1p5k.png

Not so fast my good friend. You changed the angle of the shock relative to it's lower mounting point once it is in motion. Picture this please, with the shock lowered it will rotate with the arm more than converting that motion to shock travel. That's why the nitro sedans and Proto have the shocks mounted that way, to still retain the shock travel to wheel travel part right.

*edit* Here we see what happens when you skip a step in the thinking process, the entire shock was moved down so there isn't a progression change.

The arm doesn't move up or down for that matter. Not in relation to the ground, anyway, at least as long as the wheels are on the ground. It is the car that moves up and down on the springs. If anything, the inboard end of the arm does move up and down as the car rolls.


My opinion is that sooner or later something will hook into the lowest hanging part of the car, whichever that is. Why tempt fate?

I would look into shorter shocks if there are any.

lol everyone telling him he's wrong but he's putting along and enjoying what he built. Props to WTCC for tinkering and actually enjoying the track instead of being a keyboard racer.

Props to WTCC!! This is cool!! Don't see enough home workshop mods around here :) Good on you for trying bud!
How are the lap times? Doesn't massively matter if they're not as good but awesome if they are better!

This is sort of what Schumacher are sort of doing with their gullwing arms on the Mi6 and the drop-mounts on the Mi5. In the world of short shocks, Schuey continues to use "standard" length shocks by dropping the lower pivot ball mounting point on the suspension arm. Of all the cars I have, my Schuey is my favourite at the moment :)

Experimenting is good but my question is not answered yet. The lowered links close to the ground will be an issue....

But my opinion is that this is the result of the commercial bullsh*t talk from Xray as if thos few grams lower positioned shocks is making a difference.

Thanks for all the critical and positive feedback guys!

Of course the pivot point is now different. But the amount of angle change is so little that it feels the same. I can feel every angle change on the shocktower very good. And feelingwise this stayed the same.

Now again for everyone who thinks with this conversion the car constantly rips holes in the carpet or hits the curbs or something else:
Today I was on the third different track. And guess what, again the lower mounts weren't hitting anything :weird: Also who thinks I am an idiot who doesn't know what he is doing, is wrong. I am not an outstanding driver, but won several races on regional level and train with some fast guys (today for example with Dominik Greiner). Some of them have the new T4'18 and I showed them my conversion, we made race simulations together... I don't need to embarrass myself in public with something that doesn't work.

@Roelof: Your question was answered three times already. The only issue of this conversion is that the car stays flatter and carries more corner speed. But hey, you don't believe me, that is ok, too ;) It is not like you could build this for little money yourself...

Now to something positive: The training was awesome today. Together with Florian Botzenhart (german national vize champion in the stock class) I worked on the cars setup. His T4'18 reacted pretty similar to setup changes as my car. So we constantly improved. He watched how my car behaved while cornering and was stunned how little it leaned to the outside of a corner. In the end split blocks for the front rear arm mounts and two millimeter shims under the inner camber links made a huge difference (nearly two tenth per lap). The car cuts through the corners very well and creates a lot of traction even with Volante tires. What I like the most is that I can drive over the curbs without rolling the car. Most of the times the car doesn't get unsettled at all.

Later in the week I introduce some more little mods.

It's cool what you have done. The top Xray team drivers here in the UK actually ran the T3 shocks with the Reflex towers on some of our really bumpy outdoor tracks on the 17 car, this also helps with riding the kerbs.

How many shims you had under the inner camber link before?

Does that raise the upper shock mounting? Not versed on Xray on road stuff.

I believe you and am already planning to fabricate the parts needed for this mod. Thanks for sharing!

@30tooth: Before I shimmed the inner camber links 1mm front and rear.
@BD1541: PM me for the digital drawing if needed ;)

I'm not sure, I don't own any T3 shocks or Reflex towers myself

The shock are longer than the T4 so maybe the shock and shock towers are higher. Thanks anyway :)

Many of you will have recognized on the above posted photos, that I not only used a shorty lipo, but switched the position of servo and belts. These mods are a little special and will not give any speed advantage, but may be useful for weight balance and strategical weight placement (when using a shorty lipo):

https://abload.de/img/img_7871zmsi6.jpg

Switching the servo to the right side is very easy on the first sight. The inner servomount bulkhead is in the center line, so it can stay where it is. The servo mount graphite plate can be flipped over and mounted with button head screws, at least in theory. Depending on the thickness of the shims used between bulkheads and topdeck, the graphite plate with buttonhead screws won't fit under the topdeck anymore. I use 0.5mm shims under the topdeck and had to mill a mirrored version of the graphite plate. I used this opportunity to reduce the width between the servomounts to 48mm. The distance of most servoears is more narrow than what Xray delivered with the original graphite plate.


http://abload.de/img/170c8e45-2374-41a8-aqju57.jpeg

https://abload.de/img/593b1314-fcc2-40cd-b7su7j.jpeg

Now, with the servo on the right side it will be in the way of the long front belt. So this will have to change sides, too. Turning the spool and diff this done very fast. Of course no gain without pain (= collision :( ). Unfortunately the frontbelt rubbs on the motormount (from above). I built a small belt tensioner to lift the belt right above the motormount (made from two flanged bearings and a part I had laying around from my TT-02).


https://abload.de/img/img_78666ys8i.jpg

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Another change is neccessary depending on your front suspension mount setup. The one piece FR mount will be in the way :cry: So split blocks are the answer here. But how to gain back the rigidity of the one piece block if needed? Of course (!) use the ARS suspension mounts in front and connect them with a graphite plate. Like this it is also much easier to change the flex characteristics in front. Right now I prefer the split blocks for making the car feel like on rails.

I can imagine many of you thinking: "What a pain the ***. So much work for what?!" I guess shorty lipos will sooner or later become popular or maybe replace full size packs. If that happens you have an alternative on what to do instead of just placing weights where the fullsize lipo was.
Lets also hope that the weight limit of 1350gr. will drop to 1300gr. soon ;)

Have a nice weekend!

Once again you come up with an amazing idea and execute it. To be completely sincere your TC6 mods were more over the top than this but nevertheless you are a gifted individual.

Thank you! The good old TC6 days... This chassis needed a lot of attention and also gave a lot of opportunities to tune it. The T4 is much more complete and easier to drive fast. Also the hierarchy of my interests shifted a little bit :blush:

Nevertheless the old fever is still strong and received new heat today. I was again at my "hometrack" in Senden today. The training started weird, with my actual setup beeing slow and the car not giving much feedback. Fortunately I could improve step by step and finally found an awesome setup which really suits the lcg conversion and the track. Today I improved my fastest lap by 2,5 tenth. Still laptimes are not consistent as I want them to be. The car is a little to agile in the last third of the corner. Which is no real surprise, because I have just 1.5 degree of toe in at the rear :sweat: Yeah, that is one of my peculiarities, setup wise.

https://abload.de/img/de5af255-5c90-465a-877kgg.jpeg

https://abload.de/img/42139045-35f1-4cd2-8msj1c.jpeg

https://abload.de/img/68382330-dfe2-4d45-bc7ja5.jpeg

Next week the chassis will receive new bearings and maintenance. I will post the setup sheet then, too. This setup should work very well on small tight indoor circuits.

Now my setup from yesterday:

https://abload.de/img/bildschirmfoto2017-10e5kfn.png

I am still excited about how this car performed with this setup :smile:
Just be careful. The car is very agile which suits small tracks with a lot tight corners. For larger flowing tracks use the lower graphite plate and more screws at the motormount.

If you are open to it I can give some setup advice/things for you to try based on your feedback and that setup.

Where the rear bracket bolts to the rear arm is now the lower shock position. Even thought the shock is Angled and bolted up in standard position

It's like standing shock waaaaay up. Imo

Subscribed :)

Think TA03, shocks mounted low as well

Of course! I am always open for advice. I will try and see if it suits my driving and the track next time :nod:

Thanks!

Going by your setup:
1. narrower front end using bushings but increase width back to maximum by using wider wheel hexes, middle height bushings(try centred dot and inmost, see which one you like more);
2. now use the same rear bushing configuration as you have in the setup but raise them to top position.

Both changes increase roll stiffness (not bad by itself) but most importantly keep the roll centres a bit higher (they are bellow ground stock, that is a crutch).

3. now that you've increase roll stiffness you have two options, 1 if the car is too stiff and the wheels get off ground at every tiny bump them the springs are too stiff and you need softer ones. 2 the car is too responsive during cornering, increase camber link inner shims by 1mm front and rear and use thinner roll bars.
4. I think your front bushing configuration is the culprit together with the flex. See the Ford GT arm sweep configuration.

https://cimg6.ibsrv.net/gimg/www.rct...5fe0c64fce.png

Now that is not what I had imagined :weird: But is crazy enough to try it :lol:
On what track do you use this configuration?

Trick question! Everywhere, because if that's what the tires like they work almost everywhere with small alignment changes.

If the pivot points are the same relative TO EACH OTHER than the arch is the same regardless of where the mount's attachment points are...

It's other way - with lowered pivot, it's like whole arm was lower, just without effects on rollcenter. So theoretically, dampers should be more vertical, than stock. It's all about angle between damper and line between lower damper pivot and arm's inner mount.

Two examples:
TA03 - it had low shock pivot in arm, lower than inner arm's mount, but also nearly vertical shocks. I believe it was only way to do proper geometry, because gearboxes were in way for laydown shocks.

IC cars - even in this thread was picture showing car with nearly horisontal shocks. But you can notice, that it also had lower shock mount way above arm mount

with this type of configuración the car should have less chassis roll correct ? It should behave more like a 1/10 ic car and generate more grip through the corners ? Overall flatter

Now that you mention ic TC yes, their suspension is similar to that one I shared and has less roll than normal electric TC. The main points are the upper arm angle and upper arm length compared to the lower arms. If that generates more grip depends on many tire parameters like sensitivity to load, construction and chemical composition.

yeah for sure, I’ve done some testing myself but in gt 1/8, I basically tried convencional stand up shocks and then I DIY some extensión like those found on 1/8 IC Lola and I found that the car improve in many area it would carry much more speed through through the corners , chassis roll decrease quite a bit, it was less likely to lose the rear end mid corner, better steering and it was overall better, now I’m looking to get into 1/10 EC but I find the suspension to be quite Rollie and not nimble enough, could you further eloborate in the suspension ideas ? That i could potentially use? Right know I’m wanting to do something very similar to a 1/10 IC suspension geometry

Cant compare both cars, the ic ones have the centre of gravity far higher than electric TC. If you've made extensions then you positioned the lower shock point closer to the wheel, therefore increased wheel rate (stiffer spring at the wheel).

I'm testing today some changes to a standard TC suspension to address the high amount of roll these cars have, will update here soon.

yes that’s correct , what changes will you be trying ? I’ve tried just laying down the upper part of the shock without any mods and I didn’t really like it still felt like it had a lot of roll

Lower arms level and compensate the upper arm angle so the roll centre remains at ground level or slightly above, that cut roll tremendously. The way you are doing it's softening the spring at the wheel, it will roll and bottom out more. To lower the CG and lessen roll you have to do like xray ulp shocks, shorten them and mount them lower.