WRXNFXKC

So, I have a kartboy dog bone. It is illegal in Auto X.

So I decided to modify my stock dog bone.

Supplies:

Wax paper
5 minute Epoxy
Masking tape


Here is the Epoxy I used


Put a circle of wax paper covering one side of the big end of the dog bone. Masking tape it on well


Mix up the epoxy, I used probably 2/3rds of the tube.

Start putting it down the holes, also fill accross the lower parts of the top.


This is the wax paper side after it is removed.


Any over run can be removed with a utility blade.

Here is the epoxied stocker next to the Kartboy.


Before I epoxied it I put a large Phillips head in it and wiggled it, I could get at least 25 degrees each way.

Now it is rigid like the Kart boy.

Remember to tighten the dog boy down well or it will clunk, badly.

 

zique

I'm no expert, but I think the Kartboy dogbone is beefed up in the middle to accomodate the extra stress by having less give in the bushings. Maybe I'm wrong, but I'd be interested to see how this works out for you. Keep us updated!

DustinTarditi

I admire your clever approach, but think the epoxy will not hold up to the forces applied once it's on the car and in use.

Is the dogbone illegal due to SCCA autoX regs or local class regulations?

I ask because I've got my car modded for street and rallyX use, but the mods put me in a ridiculous class in autoX competition-wise.

WRXNFXKC

I think the epoxy will not be the fail point. It is pretty hard and stabe and really one big piece. The weak point is definitly the bone it's self.

About Auto X other places I posted this I got the same question, I should have explained.

I am in E Street Prepared in Street prepared you can have any motor mounts you want, but they can not contain any more metal than stock.

Since the middle of the Kartboy is metal, FAIL.

As for it breaking by transmitting more force, that is possible.

I have Race gearbox mounts and STi motor mounts so my hope is there are less forces to deal with, also the front bushing (small one) is still stock and pretty soft rubber.

If I break it it will be a NVH thing not a break down.

Oh and if it breaks I will get the STi one and swap it with the Kart boy for the off season.

goixiz

hers one that broke and where it broke
broken pitch stop

BAMBO

http://www.groupa.ca/pr_pitchmounts.html

Check this out, a buddy of mine fabs these for a lot of rally teams. They are about $90CAD to buy and are tried tested and true on the Canadian Rally Championship by at least 4 different teams in all classes.

If you do order, let Derek know that Bambo gave you the info and you should be able to get a bit of a discount!

sparspecker

Speaking from experience, I find the upgraded dog bone to be a bad idea. The mount is designed to shear when the car is involved in a head on collision. By shearing it helps the engine to drop under the car and not into the the drivers compartment.

wesly

Niceeeee

Mr BadWrench

Devcon, Flexane 94 or Flexane 60(softer) would be better choices for your project, its costs a bit more but is less likely to fail.. your epoxy will crack and shatter suddenly...

If you insist on using epoxy the 5min kind(fastest setting) is the weakest of the line... look for 60minute epoxy because the longer the curing time the more durable the product is.

seanathan

what he has is actually devcon epoxy

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Mr BadWrench

he is using devcon 5min epoxy which is the weakest epoxy of their product line. flexane 94 is about the best suited to what he is trying to achieve.

kc0034a

wow thats a pretty interesting idea to epoxy it

senortighto

looks good

vincent-h

have your tried epoxing along the bone where there is that indentation to fill it out? I would think that would help in make it more rigid and beefier in teh middle much like the Kartboy one.

Mr BadWrench

vincent-h Even the flexane 94 at 2800psi would be hard pressed to hold onto that surface. The 5min stuff thats only rated to 900psi would not have a chance.

The reason the current mod should work is that the epoxy is encapsulated inside the bone.. possibly if you punched a few self tapping screws to give the epoxy more bite it would not weaken the part too much.... I think stopping at stifening the bushings is the way to go in this case though.

ronin_hungary

I have the Beatrush unit and it is excellent, if you car is not a daily driver.

As for strengthening the OEM pitch stop, you can either get the STI with uprated bushings or get e.g. PowerFlex or Whiteline bushings to fit inside the OEM plastic "frame".

Cheers,

R.

c0mpl3x

just grab a chunk of solid delrin or nylon and make your own

jsnm

3m windo-weld works great as well.