Raced my mid today

So finally there is a EP offroad race in MYMTRG track. Unfortunately there wasn't enough entrants so all the EP 1/10 rc vehicles had to be raced together. In the field were 2 Durango DEX 410s, 2 Losi 22s, and one 2WD SCT. On Saturday, the track was mildly muddy, so I decided to use OT-66 tyres. It wasn't a really good race as I did not have any practice these last two weeks. The car kept overturning easily in the ruts as it seemed like the spikes were digging in too much in the bumps. However I finished the race without damage to the car, except the gear cover. I managed 5 laps in 5.08 which netted me in 3rd place for the first heat. Suddenly my boss called me and ask me to haul my butt to work. So I had no choice but to leave the 2nd and 3rd heat. Sure enough some one else beat my time and I slid down to 5th.

On Sunday, I used Lazer ZX-R tyres, figuring that the track was still damp and the hard spikes will dig in well. In the first final I did not do so well, but better than Saturday. I still made 5 laps , and cut down my time to 5.02 which netted me a 3rd place behind a TLR22. Still not happy with the car overturning, I increased negative camber on all 4 wheels, I surmise this would help prevent the car from overturning in the ruts. I also tightened up the slipper clutch to gain more speed and changed my driving style to go easy on throttle coming out of the corners, then gradually increasing speed. It paid off in spades and I cut down my best lap time down by 6s. I also finished 6 laps this time. In the 3rd heat I manage to repeat my performance. 2 finals were tallied and I won 2nd place behind a DEX410 driven by a young guy name dragon. I was really happy with my Optima Mids performance , and the new arms and PEEK c hubs I made were really strong and did not fail even though I took some pretty nasty hits. The Optima Mid has gained the respect from the newer generation after this race. The young guys were surprised with its performance and silence. 

 

 

 

Gear Diffs Yet Again

My rear ball diff failed on me last sunday while batting a Durango DEX410, embarrassingly. I really believed I could have at least  kept up with the DEX410 if my diffs were working. I am now installing gear diffs in my MID. I used Xray TC 300,000 gear diff oil filled only half. I did this to make sure the diff wont unload too easily and also the pressure in the casing will not be too high and cause the oil to leak out. I tried this and the diff is quite hard but still movable. The silicone oil should ensure that the setting remains constant and wont loosen up. For the front gear diff I used RIDE TC putty, to make the front diff almost like a spool, just the way I like the car to handle, very stable.
I will let you know how it goes. I hope the large bevel gear will not separate out from the shaft, or I would have to take the car apart yet again...

Latest updates and changes-Back to Lazer ?

I just recently got a new batch of layshafts , and I haven't been running my optima mid since last year, when I sold my layshaft to Daniel Rowlands. My car has been running for some time now with the optima mid suspension, with the back arms flipped so that I can place the shocks behind the wheel in order to clear the layshafts.
Last night while I was looking my car over I noticed that the rear CVDs were exiting the diffs at an angle, it was swept forward. That means the wheelbase was also reduced about 5mm. There was also noticeably a huge amount of rear toe in, which isn't really a bad thing.
However, the forward swept CVDs could pose a problem.
Forward swept CVDs will pull the rear suspension down under acceleration, and rearward swept will push the rear up, both conditions are not good for optimum handling. I did find my rear end washing out every now then. I then tried placing back the Lazer rear arms, and sure enough, they exited straight as an arrow. If you remember , I had problems with snapping my Lazer front C hubs, so in order for me to use back the Lazer arms, I had to find stronger alloy c hubs. An idea just came to me, why not find drift car alloy c hubs, since touring and drift cars uses smaller components similar to the lazer and optima, I am bound to be able to find one that fits, then I would have to use the knuckles  that fits that c hub.
The MPP arms seem to be tougher than Kyosho arms, simply because MPP arms are more flexible. I don't know how that will affect handling, but for sure my car will be more trouble free. I have been hearing from other people in the know, like terry sc who swears the Lazers suspension is much better than the Optimas on rough tracks, so that's one of the reasons I want to switch back.
However, I did find a peculiar thing comparing lazer and optima arms. The shock mounting holes on the lazer arms are much further outwards. I believe they did this to get back the same wheel rate as the optima since Lazer arms are much longer and will give more leverage. Still I wonder if the wheel rate on the lazer arms is enough for rough tracks, as I believe the optimas shock positioning should give a softer suspension which will handle bouncing better. well, time for testing then.

Another thing I found out about kyosho big bores is the kyosho rod ends seem to be rather weak. I used X ray T2 touring car rod ends with their balls and they are much tougher, but they cannot go into the lazers capped arm because they are 5.5mm wide, compared to the kyoshos which are just 5mm. Anyway, I will try using back the kyosho pieces but this time I wont be removing them so often, and will put threadlock on them.
I will keep you guys updated on my front c hub findings.

Back to the Optima (suspension)

Ok, i love back to the future, since it was so 80's. So thats how i came up with this title. I was supposed to race my Mid in a race last week but i broke one lazer ZX front c hub while casing a big jump. I got so fed up and went back to the original Optima Mids suspension. One of the biggest reasons was i had  a pair of A & L alumimiun C hubs with bearings and i think i could practically bulletproof the suspension with these c hubs.

The A & L C hub, with 4x8x9x3 flanged bearings.
Thats a ZX-5 plastic knuckle. i ground off 2mm from the top of the knuckle to be 20mm then only it could enter the c hub.

another view.

Rear Optim Mid Suspension with the arms flipped so that i can place the shocks at the rear like the lazer. Thi is done so that i can clear the new layshaft .

Position of shock on shock tower.

I tried the car today on the terrible offroad track and it was much better than before, simply because i removed the durango shock boots that was interfering with smooth suspension movement. the Mid could clear the big jumps most of the time and landings were good. It also handled the bumpy sections rather well. Of course the tree roots still posed a problem, but the car was definitely better. Also since i was using modified kawada touring car knuckles, the mounting for the kingpins was too short causing the kingpins to dislodge itself and ending my testing. i went home and then decide to grind off the ZX-5 knuckle by 2mm at the tops so that i can slide it into the c hub.The zx-5 kunckles felt a lot more secure, and the kingpins felt secure in them too. i think i pretty much nailed this problem with this solution. will test again the next week.

Big Bores, Such a boar??

I finally tested the big bores on my Optima, and at first i had 20wt oil in them , and they were too soft. it was bottoming out too easily. i took the advice of some drivers at the track, and put 50wt oil in the front, and 30wt in the rears. The car is now much easier to drive and i am finally clearing the jumps, small and big most of the time ! Before it was only some of the time. I also tried to place the front shocks to give it more ride height and droop, and i found that the car goes over the small bumps much better instead of nose diving, so it goes through the whoop de does much quicker. I also learnt a technique to clear the big jump, go up the hill quickly build momentum to the jump and at the end of the jump brake, the car will land nicely on the backside of the landing jump. However i still find the car under powered with a 10.5T, so the next step is to get a 9.5T or 8.5T. Also it seems my 5 year old Speed Passion GT1.1 ESC is finally giving way. after a few hard bumps, the calibration of the ESC went off. I had to recalibrate a few times. Now i have to buy a new BL sensored ESC and motor for my buggy, more expense needed, becuase of the coming race on the 25th. I managed to break a front right lazer arm and bend the RCPS titanium hingepin from hitting the backside of the jump squarely. So now i place ZX-5 arms and uprights on the front end of my Mid. I will also drill a few more holes on the rear of the James Instone shock towers to give the rear a little more ride height and droop becuase it seems to snag at the cement hill bank while going up, losing some speed build up for the big jump. will report back in 2 weeks. In the meantime i will be driving my Kawada SV-10 Alcyon II this weekend and giving my Optima Mid a rest. Dont worry it will come back with a vengeance !

Some Old Pics

Here are some old pics of my cars, many of  them of the optima mid

New Videos Slipper Clutch and OT-66