I have the Bonez Hi-Flow cat, and to use the OEM air pump, it came with a 16" long piece of metal pipe, and 2 4" rubber hoses with hose clamps, one that attaches at the top end to the air pump, and one that attaches from the pipe to the Cat. These parts have only been on my car for about 15K, and I have gone through 2 of these extension kits.

The problem is with the hose that attaches the extension pipe to the Cat. The hose keeps melting
through, and then the extension pipe drops down, and eventually comes loose at the top.

My question is, is there a better way to install this? I can't remove my air pump, since I am running a Cat for emission testing purposes. Is there a hose material better suited for this application than rubber? Any help is appreciated.

Thanks,

David

 

I bought a section of silicone heater hose at NAPA.

 

Mine had no problem with the heat. It didn't even dimple it at all.

 

How far is the end of the hose to the cat itself? My Random Tech provided a pipe that came off the cat and the end of my rubber hose is at least a few inches away from the cat body.

If its right up at the cat body, maybe you can fashion a longer piece of pipe coming off the cat to relocate the end of the rubber hose further away. Or silicon hose might do the trick, if you can find the size.

 

There is a pipe coming off the cat body, approx. 4" that the hose connects to, so the rubber hose is not touching the cat, but it is apparently putting off enough heat to melt the rubber hose.

I'm going to stop by Rotary Performance at lunch today and show them my problem, and see what they suggest. Thanks for the help!

 

Chris at Rotary Performance gave me a reinforced, silicone hose for the cat end of the install, so all should be good after tonight. Thanks for the suggestions!

By the way, I asked Chris about the 20B motor for their drag car, and he said it was just about ready to go. Twin ball bearing turbo'd 3 rotor. SWEET! They have been testing it in the chassis of the 2nd FD they are building for Chris to drive, so the RX-7.com team will be supporting 2 FD's, one 20B with Ari driving, and one 13B with Chris behind the wheel.

 

I searched all over town for that special cat air tube high heat hose and couldn't find a shop that sold it. So I went to a muffler shop that charged me 35 bucks to weld a tube on for me that didn't conduct the heat that would melt the hose.

 

Garfinkle used copper tubing on Cam car to attache to the cat ,worked good cost penneys.

 

Just burnt mine through at the weekend.

Nasty burning smell, and lots of noise.

I thought silicone hose couldn't stand the sort of temperatures near the cat, anyone had any success with silicone?

Oh, does anyone know the inside diameter of the hose, so I can order some before crawling under the car?

Thanks,

Richard

1994 Efini RX-7

 

As I mentioned before, I've used silicone heater hose as sold by local autoparts stores with no problem within 2" of the cat. I have had one of these on a car for 5 years without any problem. The parts stores keep it behind the counter so I have had to ask for it specifically. I don't remember the size but can check tonight.
You can also order it from http://www.mcmaster.com