RoketRdr

iTrader: (2)

That's actually normal wear and yours looks better than mine do after 12-15 tanks. The discoloration comes from riding on the inner bearing race but if you put a mic or caliper on it you will find that it hasn't lost any of its surface area. From the looks of yours I would say your temps are running lower than what I'm seeing. But I'm also convinced that the big discoloration on my pinion shafts is happening when my inner bearing gets wasted and the shaft pushes up against the outer bearing at an angle since that's all it has to ride on. Its 2am here and I've got to be up at 5am so I'm going to bed. But I will snap some pics so you can see the difference between the two and what mine have looked like after a diff failure.

rptech1

Hi Guys,

We have run in an event that had a 5 min qualifies and a 20min final the temp was around 34C for the day, we check all running gear and no sign of diff problems. We pack all bearings with grease. Do you guys fuel your cars from the front hole in the windscreen or side window??

RoketRdr

iTrader: (2)

Better start checking your rear diff temp coming off the track. That will tell you if there is a problem. If you're not checking the temp then you will get no warning and it will suddenly crater shoving the outer bearing out of the diff housing and drive shaft forward.

MantisWorx

iTrader: (28)

There are lots of variables, a 20min race should not be an issue but 30-45 min is where the problem happens most of the time but not all of the time. if you run 7min at a time and then cool off they will last forever. Since its heat related as long as you dont get to the point where it starts to distort you will not have an issue.

I use a fuel gun normally.

British Menace

Hey all....

On this rear diff' overheating issue.
Are we still thinking the heat is coming from the engine/ header or the helical gears (rpm related)? ......... or a little (alot) of both?

BM

RoketRdr

iTrader: (2)

From the engine heat and header. On the last one I blew up the front of the diff was over 200* and the chassis directly under the diff was almost 120*. Marcus was seeing high temps as well and once he installed the heat shield on his car the diff temp dropped to 110* right off the track.

MantisWorx

iTrader: (28)

Its a little bit of both. Helical gears by nature are much stronger than straight cut gears but less efficient, the extra drag does put off slightly more heat but not really enough to melt plastic. The header is very hot and about an inch away from the rear gearbox. I think that the combination is the issue, my 43/13 gears came today as well as my new machine so I have lots to do over the next week!!

Something else I am running into with the gearing is this: In homestead Paolo was running FDR's of 11:1 in first gear and 7.8:1 in second gear, he was able to hit 58mph on the speed trap but keep in mind that the trap was not at the end of the straight but a little past mid way. My car geared at 8.6:1 second gear was able to pass most cars at the very end of the straight. but if i went to a 40t second gear it just felt sluggish which blows my mind because 8.6 to 7.8 is a huge difference. In the 1/4 final i was running a Bonito which is a long stroke 7pt. Sunday morning in practice i tried a 41t and it had better midrange but when i went to a 40t it just seems to have lost power all the way around and the MPH was the same with both gears, i was clearly slower on top speed but monstrous in the infield???? Drivetrain efficiency loss is exponential ie you may only lose 1% at 5mph but the faster you go the higher the drivetrain loss is. It is my hunch that the helical gears just will not allow me to run higher ratios without creating excessive heat and drag. We will see soon

RoketRdr

iTrader: (2)

You're just too slow is all the problem is. You need to learn how to drive faster.

Joe Kimble

iTrader: (19)

Lol of the year...

THE FRIDGE

iTrader: (7)

Hey Marcus
Stupid question: do the team c one piece engine mount have more adjectment then the standard engine mounts? I was stripping gears yesterday. I could get a good mesh when I changed to the 17/21 pinion and 45/41 spur. Did 2 sets of gear and finish the fainl with only 1 gear. Before the final I put on a 46/41 which worked well but lost the 41 in the end.
Cheers mate

THE FRIDGE

iTrader: (7)

Hey guys
Have you seen the new blitz GT body's. They look great

MantisWorx

iTrader: (28)

Its the same dimensions, best bet is to grind the chassis holes about 2mm towards the centerline. My billet gears are bigger in diameter and can be used without the grind work. and the new gears i will be making for the optional gearset will be even bigger. Also the sotck gears are abrasive and eat up the pinions quickly.


Its just the Alpha body and may or may not be thicker, same mold at least it looks that way!

san.

iTrader: (61)

Any news?

MantisWorx

iTrader: (28)

Not sure when i can place an order from the factory, shipping on a chassis is about 40.00 alone and the only way for me to get free shipping is to order around 3k worth of product!! I will ask Roy if he can have HRP bring a few chassis into their warehouse.

san.

iTrader: (61)

That will be great, thx.