I got a HPI RS4 2 the other day. One of the AA batteries came loose while I was driving it. Lol...when I was at WOT.

Luckily, we have curbs that are sloped up. The car was running probably about 30mph when it jumped a curb and landed up side down. I don't want this to happen again, because I may not be so lucky next time.

What can I do to keep the servo from staying at WOT if I lose power?

Set up a throttle return spring that will pull the carb closed when radio control is lost.

Also wise to use a reciever pack instead of the current holder with 4 AA cells

I'm sure I can mock one up, but do you have any pictures of that setup that I can work off of?

Any one in particular?

One time I decided to take easy on battery matters. I didn't recycle the battery thoroughly on the night before race. Instead I simply discharge it, charge it and forget it. I thought 1000mAH peaked is enough.

On heat number 3, the car went straight to the wall . Lucky the main chassis was not damage, except rear suspension arms, rear upright, lower suspension mount, they were toast.

this happened to me in my RS4 3 SS, my battery pack fell out, and at full throttle heading staright for a parking curb, neddless to say that was the end of that car, the body was broken at the wheel wells, the whole front suspension broke and the shaft drive pussed back in my tranny and strippedthe screws, needless to say its now my brothers parts car, frame bent, they rated the .18ss at about 50mph+ and i dont know how fast it was going but had about 100 feet to get max speed... so ever since got a return spring and man it works great there only $7-8 froma hobby shop, and well worth it, cause that accident cost me a $1000(only cause i went and bought a brand new R40HE with Picco Red dot engine ) which is much more fun ...

some servo's go to heavy for this, so you can not do this on every servo there is....
A too strong spring will heavily decrease battery runtime, thus actually initiate the problem! or even kill your servo....

thats why i dont have one on my R40 cause it wont pull back my servo, so what do you do in this case, besides grab your hat and say to your self F^&k not again??

cut the fat part of an end of a ballon for a return,use around the carb

Wouldn't the heat from the engine melt it?

heat wont melt it, you can also put the baloon around the reciever so moisture doesnt get in, or use elastic bands around the throttle.

Many tracks require a throttle return mechanism. How would you feel if a runaway wrecked your vehicle.

Vehicles are an investment, why leave a non closing throttle to chance?

Use something like this

http://www.amainhobbies.com/product_...-Return-Spring

or buy some ponytail rubber bands at the market and hook them around the carb throat and carb slide.

Protect yourself (and me) against runaway damage.

But if you do this on only one side, the carb will bind.

you could also use an electronic failsafe. it has saved my car a few times.

electronic failsafe won't work if yr rx battery goes flat.
electronic failsafe is to safeguard from signal loss from yr tx.