what is considered the "stock setup" diff fluid to use for racing when using the gear diff?

Setup
 

On a small carpet track with lots of turns and short take offs, whats a good setup for Spur and Pinion. I run an Orion R10 esc and orion mod 7.5t. Also I run another setup with LRP Tc Spec with a x12 8.5.

I am getting alot of heat with the LRP. whats the best way to keep the temp down?

5k is a good place to start. Put green slime on the paper ring to keep the fluid from leaking out so bad.

Too much motor for the esc, you can run a fan.

The ESC has a fan. Its the motor thats heating up quickly.

try a smaller pinion then.

Sock is filled with black grease which is about the same as 3,000wt diff oil.

I run 5k in my truck and going to test a gear diff with 3k in my buggy tomorrow

That sounds about right. I know people were getting diffs in the first couple of batches that had low to almost no oil in them. But that was not diff oil, it was oil to prevent rusting on the hardware.
I have been running 10k and like it. good traction on semi loose dirt and tons on hard packed blue groove. The SC10 has tons of steering so i really didnt notice this affected it. Ran about 30 races on it befor I disinigrated a washer in the diff and the pin fell out. rebuilt it and so far so good.

Battery question
 

My local track is going blinky mode for stock 17.5 SC. We were running open timing. My sc10 FT is setup pretty good just seem to be lacking punch. Im running gens ace 30c 4000. would going to a higher c rating really help with the blinky mode? I was thinking either promatch 60c or trackpower 50c? I have been told c rating doesnt matter for 2wd mod buggy for the most part, but it will make a difference in stock. thanks for any help

C rating could help but not as much as you would think. Running a stock motor will not draw as much amperage as a mod motor will but having as much possible amperage available will help durring long runs. I would look to add some static timing on the motor. Its doesnt cost you any money since its just an adjustment on the motor. What speedo/ motor are you running.

Tekin RS with a Tekin Redline 17.5 in the ft sc10 and an RS with a redline 10.5 in mod b4 buggy. It just seems like I dont have the punch the other drivers do.

try 75/26 with max timing on the can on the 17.5

you should have plenty of punch with the 10.5 in the buggy as long as it's geared right. i forgot how my 10.5 was geared when i had a 10.5 in it.

Also make sure your settings on you ESC are good. Mainly the current limiter. I dont care if you have a 1000C battery, if the current limiter is active, it wont do poop because its limited at the ESC.
Like it was said above, try that gearing and adjust timing as needed.

Yes, make sure you're not running any CL in 17.5 blinky class! Start with Randy Pike's setup sheet for 17.5 SC and go from there. You will have to set the timing profile to "1" if you copy his sheet for blinky.

Thanks everyone I was pretty sure I had the CL off but now im not sure LOL. I will check everything before I head to the track. Yeah the buggy is fine I just cant get the hang of driving it.