old_dude

iTrader: (1)

I have now added the FWD version to my collection. Interesting change as it is the 6/4 setup with a different motor mounting system, the servo on the other side and built for a shorty. I could see someone using a combo if the chassis and servo mount as a AWD car easily. I believe that the 5/5 would work also. Aluminum chassis is in the works.
Very interesting possibilities.

old_dude

iTrader: (1)

I am quoting my self on this one. The FWD chassis as a AWD will not work. The front belt and hence the motor mount position are unique. I overlayed the AWD chassis and that became apparent. Now using the right side servo mount (requires three holes to be drilled) on a AWD chassis and then using a shorty might be in the cards. But with the FWD I needed 30g of weight on the motor side to balance the car with that config in the FWD.
Just a engineer thinking about improving the starting point.

spring71

iTrader: (3)

We started to carry Cero Ultra / FWD kit and parts.

https://www.tqrcracing.com/shop/prod...?s_maker_id=56

FYI, Thank you.

old_dude

iTrader: (1)

Finally getting some serious track time with my Ceros. Our racing surface is brand new CRC black carpet and the groove is building. Last Saturday a fast lap of 10.3 with the Ultra and 10.5 with the FWD. Last night a rare practice day and I have the Ultra down to 9.8 and the FWD to 10.1. Dialing in the setup.
The FWD car had serious oversteer the first time on the track 2 weeks ago, to the point that it was hard to drive. I followed the Hudy fault tree setup guide to induce understeer and got it. I then started working things back out to get the car neutral. Leaving it last night it still has a little understeer so more things to do today.
The Ultra was kind of the same with too much oversteer but not as much. I made just a rear roll center and shock position change (learned from the FWD) and the car was much better. I don't know if the class will race today but if so I will tweak on that some more.
I race these cars under the accepted USGT rule set. That is a spec Gravity tire and 21.5 motor.

old_dude

iTrader: (1)

Good and bad on day two.
The ultra was a dream to drive and it was fast compared to the competition. I didn't make changes from Friday but just worked on driving the car. The great thing is it is a parts in the box setup. Springs, sway bars and shock oil. The rear diff is 10k. I have made changes only to the roll center shims and shock shims. Once I check everything I will list those settings.
The end result was a TQ and easy main win. Final best lap was 9.7 with a top 15 of 10.000. That is huge consistency.
The FWD was a mixed bag. The handling was good but I suffered a ESC failure. Qual 1 went well and the car was very good. Round 2 the car had a event when exiting a corner it just kept turning and recovery cost me a good run. Round three the esc failed. Those issues kept me from adjusting the chassis for the building grip as I had to replace the ESC. In the main the lack of those changes showed as traction rolling was now a issue and hurt mu run. I was still able to run 10.0's occasionally but consistency was lacking. Overall I qualified 2nd. based on qual 1. In the main I ran a my fastest lap of the week and my best top 15 at 10.23 avg but a couple of traction rolls negated that effort. That is where some adjustments would have helped. This car is setup quite a bit different than the kit build. Because of the end of day setup being off I won't post it but will wait until after it is refined some more.
I have a Wednesday test coming up to work on that.
The worst thing of the race day was a issue I have with myself and it does impact the racing. I suffer from leg issues where pain sets in during the run. Some days are no issue and others are big issues. Yesterday was a big issue. It actually hurt the runs. I am also working on solving that issue as well.

Chozwoz

Quick couple of questions if you have time and don't mind: What is the length of the Cero dog bones (SAK-C148D, SAK-C147B), the ones with the ball bearings on the pins? Not total length with the drive axle and joint, just the dog bone or swing shaft. I have found a website who also stocks a plastic bushing (SAK-C147E) instead of a bearing, material unknown (Delrin would be the bomb). What are your feelings on this? Do you think a swap to the plastic bushing would really affect rotating mass or are the parts too small to worry about that?

Thanks For Your Time and Patience

old_dude

iTrader: (1)

I have shattered the bearings in the front shafts on both the Ultra and FWD. I ordered that part number at Jackie's suggestion. He just said that those were a stronger bearing. I hope. Our current layout has only one straight and the car is in a turn most of the lap. I feel that with our grip level and a spool that those bearings are just overloaded. This is their first round with bearings there as far as I can tell. I have some the previous cars plastic shoes on order and a set of stafts that use them. They may fit the existing one, fingers crossed on that.

old_dude

iTrader: (1)

I am going to comment on my own post on this one. As a correction, the bearings on the Ultra weren't shattered but badly worn on the outer race. That one is confusing. Both cars use the USGT motor per class rules here. The FWD though is putting it all through the front wheels and running a spool makes it very highly stressed. I am also a mechanical engineer and called a company that makes polymer bearings for help. They are sending me test samples to test on this problem. I have let Jackie know about this possible solution. Crossing my fingers.

old_dude

iTrader: (1)

Test day yesterday with the C-147-E polymer bushings instead of the ball bearing on the front output shafts. I ran 5 packs and no failures (I didn't really expect any). I will disassemble and inspect for wear today. Crossing my fingers as this looks like a very good solution.

old_dude

iTrader: (1)

Now I get to correct my self again. The C-147-E is a steel bushing and not a polymer. I am sure this one won't fracture on the FWD with a spool. For those of you that are having issues with the front drive shaft bearings this is a good choice.
This weekend I will be testing a polymer bushing. Not a 3Racing part.
After that I will test a blade setup. This will be all 3Racing parts.

old_dude

iTrader: (1)

Yesterday's test of the Non 3Racing polymer drive shaft bearings was a successful test, sort of. They failed on the first run. I will talk to the manufacturer Monday and see if a different compound is more appropriate. They have quite a few different ones. It may be that the first ones were just to brittle.

Chozwoz

Very good info as I'm doing a slight conversion on my S64 with Cero parts: namely swapping the S64 rear outer diff joint, front outer joint and spool to utilize those bearing/bushing type dog bones. Actively following! Would Delrin be a good choice for the bushings?

old_dude

iTrader: (1)

The company I am working with has many compounds to try for a polymer bearing. I went with their choice the first time around and for sure it was too brittle. A more resilient material is going to be better. I have to balance durability and wear which in this spot is the engineering problem. Luckily the company I work with will engage.
My suggestion is to use the C-147-E steel bushing for now. The other is another 3Racing part bin with blades.
The Cero series has a new outer bearing and hex drive system so be aware of that difference. It requires different bore in the knuckle bearings.

Chozwoz

I am aware of the new outer drive and hex system, they say it's similar to Awesomatix. What I was hoping to do up front was take the Cero SSK and incorporate the stub axles from SAK-X27 that way it should fit the existing hubs up front. Cero front spool and inner drive joints are already installed perfectly. I had to hog out the center hole in the pulley with a round file to fit it over the bearing lands on the spool and then shim each side 1.5mm behind the bearings to kick them out enough to properly sit in the bulkhead, again fits perfectly. Waiting on my next shipment of parts from TQRCRACING this week. I'll let you know how fitment goes.

amp3d

I realize it's like apples and oranges since they are different platforms, but for people that have used both; how do the laptimes on the Cero ultra compare to the s64?

Is tuning on one easier than another from a noobie standpoint?

I'm working on some builds to introduce some friends to the sport. Was just curious!