Team C 1/8 GT car
01-21-2014, 08:03 PM
#1007
Thing is, the helical ones feel lot smoother. As you know I did a lot of gearing testing last summer 
I ended up with 17/44- 20/40 with the stock helical ring/pinion. I didn't like the feel of the optional gears, they didn't feel as smooth as the helical ones. 17/44- 21/41 is good too when straight is over 200ft and if the engine can handle the split.
Anyway, if you can make some of those bullet proof spurs in 50/46 or 49/45 I think that would be the ticket with the optional gears and the stock 16/20 pinions. That combined with a powerful motor and you have a bullet out of the corners...
By the way, it's just ridiculous how long those spurs you make lasted me before even showing signs of wear.
I ended up with 17/44- 20/40 with the stock helical ring/pinion. I didn't like the feel of the optional gears, they didn't feel as smooth as the helical ones. 17/44- 21/41 is good too when straight is over 200ft and if the engine can handle the split.Anyway, if you can make some of those bullet proof spurs in 50/46 or 49/45 I think that would be the ticket with the optional gears and the stock 16/20 pinions. That combined with a powerful motor and you have a bullet out of the corners...
By the way, it's just ridiculous how long those spurs you make lasted me before even showing signs of wear.
Last edited by Joe Kimble; 01-22-2014 at 05:50 AM.
01-22-2014, 05:20 AM
#1008
Yeah its a very weird thing because Tony drove his car forever before a diff blew out. I've gone through 5 and Marcus has gone through several as well. I took some measurements and the shaft has 0.5mm play in it. I started with a 1mm gap then a 2mm gap and both gave the same end result. I was blowing a rear diff every 12-15 tanks. A couple of weeks ago Marcus and I were at the track and when I come off he checked my rear diff temp and it was 185*. This past weekend I blew another diff and when I checked the temp it was over 200*. The chassis directly under the diff was at 110*. My R5 generates 250-275* of heat off the cooling head and exhaust. This is when the idea hit him that the exhaust header and engine heat were causing the problem because there's no airflow over the diff. So he fabricated a heat shield and as he stated the rear diff didn't get over 105* this weekend. Think the problem may be solved now.
I thing hit the nail on the head with the air flow over the diff. Look I'm still pretty new to gt8 and what I did to my body cut two 10mm x 80mm hole low in the front widescreen of the car cut a flap half the size of the widow just behind the engine head and folded it down to let out the heat and no diff melting touch wood.
Cheers
01-22-2014, 06:45 AM
#1009
I don't own a Team C car but have built many diffs for my Kyosho GTs and have never blown a diff since I have been running GT. Maybe it is not the heat coming off the engine more so the build and/or heat generated in the diff itself. Or, it could be an issue with the quality of some of the gears (material) that is causing the failure (a theory). When you guys build your diffs, are you overfilling or underfilling the diff before putting it together? When you build your diffs, are you sealing them properly (using more than just the diff gasket)? If you don't seal them properly, a leaking diff eventually turns into a diff running on metal to metal which will crash and burn on you. Are you guys lubing the ring/pinion gear in the diff case? Most people forget that metal on metal generate a bunch of heat (friction) and many racers don't think about coating either gear with a layer of grease to ease the friction issue. One more thing, are you using the right diff oil for your diff? I state this because of the types of engines now being used generate a lot of power through your drivetrain. Using too lite of a diff oil with a very powerful engine (especially with a ton of low-end torque) could be something else to look at as far as causing diff failure.
Again, I am not trying to step on any toes but throwing some things out that might help you guys to alleviate some diff issues.
Again, I am not trying to step on any toes but throwing some things out that might help you guys to alleviate some diff issues.
01-22-2014, 07:03 AM
#1010
I don't own a Team C car but have built many diffs for my Kyosho GTs and have never blown a diff since I have been running GT. Maybe it is not the heat coming off the engine more so the build and/or heat generated in the diff itself. Or, it could be an issue with the quality of some of the gears (material) that is causing the failure (a theory). When you guys build your diffs, are you overfilling or underfilling the diff before putting it together? When you build your diffs, are you sealing them properly (using more than just the diff gasket)? If you don't seal them properly, a leaking diff eventually turns into a diff running on metal to metal which will crash and burn on you. Are you guys lubing the ring/pinion gear in the diff case? Most people forget that metal on metal generate a bunch of heat (friction) and many racers don't think about coating either gear with a layer of grease to ease the friction issue. One more thing, are you using the right diff oil for your diff? I state this because of the types of engines now being used generate a lot of power through your drivetrain. Using too lite of a diff oil with a very powerful engine (especially with a ton of low-end torque) could be something else to look at as far as causing diff failure.
Again, I am not trying to step on any toes but throwing some things out that might help you guys to alleviate some diff issues.
Again, I am not trying to step on any toes but throwing some things out that might help you guys to alleviate some diff issues.
No worries and thanx for the advice!
As most of you know i have been working with this car for over a year now. It is most definitely the heat coming off of the engine heat soaking the gear case. I have been from 1k to 100k in rear dif fluids and it still happened. the factory changed materials a few months ago and it got better but still there. It is not a dif failure it is the external dif case that fails and anyone that has had it happen will tell you that the inside bearing gets destroyed once the case gets hot and distorts. This past weekend in HK they had a 3hour endurance race and 99% of the cars were team C , every car that had the helical stock r/p failed within and hour and every car that had the optional straight cut gearset finished the race! So two things come from this IMO one is that helical gears create heat this is a known fact , it is also a known fact that helical gears must be precisely shimmed or else the create excessive drag. this past weekend in homestead I had a shield and had no failures Tony had no shield and his rear case failed. Another thing to think about is that helical gears will "pull" fwd and back on accell and decell, straight cut gears do not, the more i talk about the more sense it is starting to make
Jlock, everything you state though is very much true!
01-22-2014, 07:24 AM
#1012
01-22-2014, 07:35 AM
#1013
When I had my diff failure, the bulkhead had melted. I put a .5 gap and finished the rest of the summer with no issues. Course was only running 20-30min mains. I think a heat shield will do the trick.
01-22-2014, 08:38 AM
#1015
Hey mate
I thing hit the nail on the head with the air flow over the diff. Look I'm still pretty new to gt8 and what I did to my body cut two 10mm x 80mm hole low in the front widescreen of the car cut a flap half the size of the widow just behind the engine head and folded it down to let out the heat and no diff melting touch wood.
Cheers
I thing hit the nail on the head with the air flow over the diff. Look I'm still pretty new to gt8 and what I did to my body cut two 10mm x 80mm hole low in the front widescreen of the car cut a flap half the size of the widow just behind the engine head and folded it down to let out the heat and no diff melting touch wood.
Cheers
01-22-2014, 08:50 AM
#1016
HRP should have most parts in stock, did you already check?
The shield is really the only thing needed, with it the rear cvd was actually cooler than the front. It is also important to use the 84mm front center CVD, stock is 87mm but it can bind on the transmission shaft and cause front gear case issues. its actually cheaper than the replacement part anyway.
01-22-2014, 08:57 AM
#1017
HRP should have most parts in stock, did you already check?
The shield is really the only thing needed, with it the rear cvd was actually cooler than the front. It is also important to use the 84mm front center CVD, stock is 87mm but it can bind on the transmission shaft and cause front gear case issues. its actually cheaper than the replacement part anyway.
The shield is really the only thing needed, with it the rear cvd was actually cooler than the front. It is also important to use the 84mm front center CVD, stock is 87mm but it can bind on the transmission shaft and cause front gear case issues. its actually cheaper than the replacement part anyway.
01-22-2014, 09:01 AM
#1018
worst case i can order from the factory for you but shipping is high! if its is a small order its not too bad and it gets here within 4 days normally which is about the same time it takes to order within the US anyway.
I know for sure HRP has the gear holders, 2spd shoes, gears, outdrives etc etc only thing I am not sure of is the actual shaft. Tony just ordered all of that stuff before we left for homestead.
01-22-2014, 09:23 AM
#1019
LOL, i havent actually looked myself. I typically order direct from the factory but because of shipping cost the order has to be really big. Are you entering part numbers? And yes welcome to the "old as hell, impatient" club
worst case i can order from the factory for you but shipping is high! if its is a small order its not too bad and it gets here within 4 days normally which is about the same time it takes to order within the US anyway.
I know for sure HRP has the gear holders, 2spd shoes, gears, outdrives etc etc only thing I am not sure of is the actual shaft. Tony just ordered all of that stuff before we left for homestead.
worst case i can order from the factory for you but shipping is high! if its is a small order its not too bad and it gets here within 4 days normally which is about the same time it takes to order within the US anyway.
I know for sure HRP has the gear holders, 2spd shoes, gears, outdrives etc etc only thing I am not sure of is the actual shaft. Tony just ordered all of that stuff before we left for homestead.
01-22-2014, 03:44 PM
#1020
Marcus, on your next order please pick up a few replacement chassis's. I need a short wheelbase chassis. Thx