Spec Honda Pipe Cracking Solutions???...

[Ken Schilling]

I race in the S4 class with ProKart Challenge where I've only used the RLV R4 pipe (I have a '99 engine) and SwedeTech o-ringed exhaust manifold. In the 4+ years that I've raced in the S4 class only one pipe has cracked on me. For the first ~1-1/2 years I was using the homemade pipe bracket shown in the picture below and during that time is when the pipe cracked. I believe that my homemade bracket in conjunction with the harder type rubber bushings shown in the photo were too stiff. I also used four Akrapovic springs which were probably too much as well...




I have since switched from my homemade pipe support to a Hegar unit. I also use Hegar silencer & air filter supports:




I am absolutely convinced that if everything is mounted correctly, aligned properly (both vertically & horizontally), with the right amount of "float" and vibration dampening you shouldn't have any issues. The Hegar units are stainless steel and easily bent to help with alignment, a little here/a little there.

Please note in the pictures above the following:

Pipe - I use finger pull springs with an RLV pipe cradle with some automotive gasket material between the pipe & cradle. I use the RLV cradle provided with the pipe because IMO it helps line up the pipe, exhaust manifold and pipe support better. I don't use hose clamps because IMO they don't give the pipe enough float and force vibration into the pipe. I use finger pull springs & the gasket material to help dampen vibration as well.

Silencer - This is the only place where I use hose clamps to mount the silencer to the cradle, though I have considered springs... I use the gasket material here as well and I use the Hegar cradle.

In both the pipe & silencer locations I use soft rubber bushings to help align everything vertically and give much needed vibration dampening and float.

For an experiment, at my most recent race at the Streets of Willow, I purchased and installed a Honda OEM exhaust manifold (I didn't use any sealant). I found that I was getting a lot of blow-by during the Friday practice day causing a loss of power and creating a mess... I suspect that if I used some high temp sealant it would have been much less of an issue but the cleaning and re-sealing needed every time the pipe needed to be removed and replaced would be too much of a hassle. I switched back to the SwedeTech exhaust manifold at the end of the day.

I keep spare Viton -030 o-rings for the exhaust manifold and change them regularly when I start to see blow-by.

I also use two Akrapovic rubber isolated springs to attach the pipe to the exhaust manifold. I only use two springs as IMO three or four work against what we're trying to achieve with this whole mounting "system".



Last but not least, I use just a small squirt of some kind of spray lubricant (WD-40 will do) on the o-rings and/or on the ID of the pipe flange when installing the pipe to help minimize any sticking.
_________________
Ken Schilling
#21x / S4 / ProKart Challenge (PKC)
SKUSA Data Administrator

Good luck is where preparation and opportunity meet!!!

The opinions I express are mine alone and do not reflect those of any organization of which I am a member.

[james jackson]

Swivle joint like the 250 single pipes have is the only way I've seen that will stop pipe cracking

[DANNY SKAGGS]

Whew did u get the finger Pool springs?

[Ken Schilling]

[Ken Schilling]

Please post any other solutions that you have actually tried or even just ideas...
_________________
Ken Schilling
#21x / S4 / ProKart Challenge (PKC)
SKUSA Data Administrator

Good luck is where preparation and opportunity meet!!!

The opinions I express are mine alone and do not reflect those of any organization of which I am a member.

[John Denman]

I've never seen a spring clamped saddle mount system that didn't appear to increase the tendancy to accelerate cracking. Vibration/resonance tends to initiate cracking; maybe something to do with springs, who knows?

For several years we ran RCE T3 pipes; good pipes in their day, but very prone to cracking. They had a welded tab mount and using that configuration they lasted longest between cracking for us. We tried an RLV saddle mount on a few new pipes and they cracked in short order. We also found that by using large hose clamps on the saddle rather then springs they went quite a bit longer between cracking.

In the end we went back to welding tabs on all of our pipes for mounting, and they always seemed to last a long time that way.
_________________
John Denman
Producer for RTMP
http://www.kartweb.com

[jack lachut]

ken, i'm using the rlv r4 pipe with the fastech racing manifold, with the hegar pipe / silencer mount kit. i'm using the kit just as supplied by hegar with the rubber mounts supplied and the hose clamps. i have no problems so far with 23 hours of run time.

i'm using the akrapovic rubber isolated springs from fastech at the manifold.

the fastech manifold used 2 o-rings, it looks like swedetechs uses 3 o-rings??

[Chris Hegar]

Some people crack things and some don't it's just the way it goes. You really can't determine if it's the chicken or the egg because we all run different tracks with different lines at different speeds, over curbs or around curbs, off track lots or never off track, stacked in the truck on top of each other or protected from everything all the time. There is no way to determine what problem needs to be addressed unless back to back testing would be done with exactly the same vibrations and impacts replicated. Will it ever happen... I doubt it. We have no less than 300 units in the field with very minimal complaint. It's a crap shoot, to crack or not to crack that is the question. We do however take every comment into consideration so please feel free let us know what you find.
_________________
www.Hegar4.com

[Tom Barth]

Ever notice that the KZ (ICC) pipe set-ups rarely crack. No cradle? KZ pipes are also thinner to take advantage of 2 stroke pipe design, thinner is better.
_________________
Tom Barth
http://www.greenflagkarting.com/

Power is good...more power is better... too much power is just right!

[jack lachut]

chris, +1 you brought up some very good points. i saw a video of you at a big track in oregon and it looked awesome with the elevation changes.

[Jeff DeMello]

[Chris Reinhardt]

[Ken Schilling]

[Ken Schilling]

Please see John Denman's post directly below:

"I've never seen a spring clamped saddle mount system that didn't appear to increase the tendancy to accelerate cracking. Vibration/resonance tends to initiate cracking; maybe something to do with springs, who knows?

For several years we ran RCE T3 pipes; good pipes in their day, but very prone to cracking. They had a welded tab mount and using that configuration they lasted longest between cracking for us. We tried an RLV saddle mount on a few new pipes and they cracked in short order. We also found that by using large hose clamps on the saddle rather then springs they went quite a bit longer between cracking.

In the end we went back to welding tabs on all of our pipes for mounting, and they always seemed to last a long time that way."


Chris Hegar,

One question I have is the point of using either hose clamps or springs for the pipe to cradle interface. I used to use hose clamps until I broke my first pipe ~1-1/2 yrs ago. I've since changed to springs. I've had no problems since but of course they're too many variables to claim that the springs solved the problem.

Thoughts?
_________________
Ken Schilling
#21x / S4 / ProKart Challenge (PKC)
SKUSA Data Administrator

Good luck is where preparation and opportunity meet!!!

The opinions I express are mine alone and do not reflect those of any organization of which I am a member.

[Ken Schilling]