Speed run car: OFNA Ultra GTP - Neu 2215

Originally Posted by MTBikerTim

With the eagle tree graph you can click the chart settings button then go to the export tab you can save the chart as a jpeg instead of having to do print screens.

That is amazing how tall the gearing is on that and only 12000 rpm too. I'm also surprised you aren't using foams. Aren't the rubbers ballooning? Nice car though.

Ah, I was wondering how to get the graphs much clearer. Thanks for the tip. I hated when you would take a screen capture it would destroy the detail of the graph.

Ok, about the tires. On my 83 mph run I used foams. On my 81 mph run I used belted rubbers. The foams are 4 inches in diameter and the rubbers are just shy of 4, they are 3.8-3.9 inches. The belted rubbers do not balloon nearly as much as the non belted rubbers. The belted rubbers are a must for speed runs. I did notice much more traction with the rubbers, but they are smaller in diameter than the foams. Also, you HAVE to make sure they are glued to the rim really really well. I just had a friend with a rustler that hit 90mph and he is using the same tires as me. He was going about 70 and part of the tire separated from the rim and the tire exploded. It shot out all the foam that was inside the tire through a hole only about 1 inch long.

Originally Posted by tc3_racer_001

didnt you see the site, with the foams, just destroyed, looks like it would eat them for breakfast and come back for more each run... rubber while it tears may (im not sure) hold up better... and ballooning = more speed :P

The pics that you mention of the foam tires exploding are from my previous car, the "X2". The car that I am running now is the "X3". The X2 was a front wheel drive all custom car. It had the same electronics as I am running now on the X3. The X3 is an off the shelf 1/8 scale 4wd OFNA Ultra GTP. All I did was convert it for brushless. The X2 had major problems with any type of foam tire I would use would explode. I tried just about everything to fix the problem, but no luck. I have not given up on the X2 I am putting it on the back burner for now while I do some more research and design on the tires. The X2 has a much much higher potential for speed than the X3. The X2 is half as wide, half as tall and half the weight of the X3. The X2 is direct drive as there are NO GEARS. The wheels are attached directly to the motor so there are no drive train losses except for the efficiency of the motor and motor bearings.


Previous car, the X2. Project car X2 is on hold for now. Too many blown tires.


Current car, the X3. Testing in progress. Does not eat tires for breakfast...so far. This is what the body looks like after flipping at 75 mph and running into someones leg at 76 mph.

Thanks for the comments.

[TexasSP]

Looking very good. It seems the body mods you have done have paid off well. The front spoiler tabs look very good and the setup is clean.

My goal is to push the car to its limit on the 8s setup. It should be able to hit in the low 90's. Then I will upgrade to 12s.

Originally Posted by TexasSP

Looking very good. It seems the body mods you have done have paid off well. The front spoiler tabs look very good and the setup is clean.

Thanks for the comments. Yes, the front splitter and winglets are absolutely needed with this viper body. The body creates too much lift and can make the car air born at 75 mph for a 12 lb car.

[TexasSP]

Since you are local, I would love to see it run some time.

Originally Posted by TexasSP

Since you are local, I would love to see it run some time.

We usually test in the mornings on Saturdays or Sundays at Houston Motorsport Park.

But since this last test, I am finding out that we are running out of room and will need a bigger area to test. You are welcome to come as well as anyone else who is local. We have the radar and camera setup. We are on schedule to test this weekend.