The International Cessna^® 170 Association

When I bought my 170B it had chrome exhaust stack extensions that had been fabricated and installed by the previous owner. (I know, I know -- FAA. PMA. STC. 337. Blah blah blah! )

Anyway, they kept the cowling clean -- and looked great! (I can scan and send a picture if you want.) Unfortunately, one of them developed a small hole in it and they had to go. I want to replace them, preferably with approved parts. Is there such an animal -- an STC'd exhaust stack extension?

In the MX Library there is a thread entitled:
"Form 337's and STC copies Available from TIC170A Hqtr's." Have a look at this. There is a listing for "EXHAUST PIPE EXTENSIONS (170A-B)", but it doesn't say if it's an STC or 337. Contact Velvet at HQ (you ARE a TIC170A member, right? ) and she should be able to get you the paperwork.

WagAero sells Cessna tailpipe extensions--fits 150,170 and early 172,bolt on,2" longer than stock,2" OD stainless steel: p/n E-420-000....$136.75 for the pair.
They label them as "code 4",which is explained as "FAA/PMA'd,TSO'd,and/or STC'd..........."etc.
I've seen a set of these,they look like they're nicely enough made. They actually replace (not extend) the tailpipes on the Hanlon-Wilson system.

Eric

Tail pipe extensions for the 170 are available from Wag-Aero, however these are not STCed or PMA, so technically you would have to go with a 337. These are 2" extended and cost $137 for the pair.
Wag-Aero 1-800-558-6868 or http://www.store.wagaero.com

Part No. E-420-000 These are NOT chromed.

Tailpipe extensions are not legal without a basis of approval, and are guilty of contributing to exhaust system cracking and failed exhaust studs, due to length of moment inertia/vibration.

I agree with George. If you are going to spend any money, just go for the Bartone pipes that exit at the rear of the cowling and seal up those original holes to reduce cowling pressurization. A side benefit to the Bartone pipes is the nice mellow sound they give the O-300!