Xray T4 LCG conversion and more...
#16
Joined: Sep 2010
Posts: 3,569
From: My house.
Thanks for all the critical and positive feedback guys!
(...)
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.
(...)
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.
Does that raise the upper shock mounting? Not versed on Xray on road stuff.
#17
Tech Adept
Joined: Mar 2015
Posts: 163
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
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.
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
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.
#21
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):

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.


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).


Another change is neccessary depending on your front suspension mount setup. The one piece FR mount will be in the way
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!

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.


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).

Another change is neccessary depending on your front suspension mount setup. The one piece FR mount will be in the way
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!
#23
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 
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
Yeah, that is one of my peculiarities, setup wise.



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.

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
Yeah, that is one of my peculiarities, setup wise.


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.
#24
#28
#29
#30
Joined: Sep 2010
Posts: 3,569
From: My house.
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.



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