Airbox Strap longevity

[notmytarga]

I have a 1975 S Targa and have gone through 3-4 airbox straps in the 8 years I have worked on this car. I have snapped two while pulling them to attach to the mounting hooks and the most recent was just lying broken in the engine bay. It could have gotten sucked into the fan!

I have bought the $4.25 style in the past and probably have a OEM ($12) one as well sourced from my local wrench in a bind. Not sure which ones are the short life ones - I know the engine compartment is tough on parts, but this seems unacceptable.

I have thought of springing for the $20 Weltmeister version as it would match some of the hardware I painted red during my engine rebuild (crank pulley, heater fan mount strap etc) AND the red accents on my new mountainbike (seatpost binder, pedals, letttering, and Lefty brackets) It's been a while since my baby had anything significant spent on her and her birthday is coming up! I might even pull the engine to do a proper valve adjust, cleaning and headstud check.

Does anyone see short lives on the Polyurethane Weltmeisters, are they fairly easy to pull to the hook?

[schumicat]

there are at least 2 different sizes, one slightly shorter than the other. you are probably using the shorter length and it is getting stretched too much.

[notmytarga]

So I bought the $22 Weltmeister strap. The lettering is raised - but not white. Not an issue for me but it is not as pictured on Pelican.

The real problem is that one of the two straps broke within the first three weeks of installation. The link below shows the airbox straps - the OEM and cheap one say 300mm, Weltmeister gives no figure. Pelican is sending me another. I don't think the strap was defective. There is nothing peculiar about my installation that should cause these failures.....I think.

Porsche 911 & Turbo CIS Fuel Injection - Page 4




I thought it worthwhile to continue this story. Anybody else have a problem with airbox straps breaking? There is something 'meisterish' about this.

[tazzieman]

After 2 1/2 years my Welts have stretched and show signs of fatigue. Heat is clearly not kind to these anymore than it is to rubber. I may well go back to cheaper rubber ones in the future.

[afterburn 549]

I guess my mini bungee cords are not Kool ? LOL

[javadog]

I've never had to replace a Porsche strap. Maybe the aftermarket stuff is just no good....

JR

[b rock]

My strap broke while being installed.

[Tony911Z]

I'm not a big fan of the red color but my Weltmeister straps have last 5+ years whereas the stock rubber versions showed significant cracking in about a year's time.

[hbueno]

My 79 with 160,000 miles still has the originals.

[mca]

I've certainly broken a few in my short 7 years of ownership. They seem like they need more elasticity.

[NOLAsc]

In three years, I've broken one aftermarket/URO black one. Last order I bought 2 just to have a spare. I never noticed an option for different sizes.

[Bob Kontak]

Originally Posted by schumicat

there are at least 2 different sizes, one slightly shorter than the other. you are probably using the shorter length and it is getting stretched too much.

Interesting that this may be the root cause but the post was ignored.

[chrismorse]

Originally Posted by Bob Kontak

Interesting that this may be the root cause but the post was ignored.

I tried installing a weltmeister strap on my 74 and broke the tab off of the housing.

Longer would be better.

chris

[Peter Zimmermann]

I put o.e straps (bought from the P-car dealer) on my SC in 2002. They are still perfect, with no sign of fatigue, cracking, or looseness.

[javadog]

Originally Posted by Bob Kontak

Interesting that this may be the root cause but the post was ignored.

I think the root cause is people are having problems with poor quality straps. It's interesting to note the difference in experience between Porsche straps and aftermarket straps. Even "OEM" straps may be different than what you get through the dealer network, as is the case with a lot of parts.

JR

[notmytarga]

The Weltmeister strap would be easier to install and last longer if it was either 10-20 mm longer or was more elastic. My local Porsche wrench demonstrated the technique he uses to fasten the straps - pulling it to length and pegging the center of the strap against the filter intake cover to maintain the streatch to bring it to the hook. All new straps are a ***** to get on - never the first try.

I plan to rotate my straps. The left one is usually easier to get on despite it is harder to get to the hook - perhaps it is a shorter distance. I'll move the left to the right because it has been stretched for a month and put the new one on the left side.

[notmytarga]

Originally Posted by schumicat

there are at least 2 different sizes, one slightly shorter than the other. you are probably using the shorter length and it is getting stretched too much.

I looked into the length thing ten years ago when I bought my first strap. Pelican only lists straps at 300mm - other vendors also list a 270 mm strap (930-110-365-00) for later cars (77-83?) - about an inch shorter. So the 300mm straps from Pelican are the longer of the two I can find. I've thought about what could make these seem too short. I put a K&N filter in, but that does not change the profile of the filter and its cover from the stock to any discernible degree.

Originally Posted by http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_FULcis_pg4.htm#item13

Ozone decay is the biggest reason for stock rubber airbox strap failure, but now your worries are finally over. These Weltmeister Air Box Straps are made of a special polyurethane blend that will protect from cracking and stretching.

My worries are not over. Eventually I'm going to have one of these rat up my fan or worse. If I were making an aftermarket strap valued at $20 it would not break and be easier to install.

[djb25]

I had a set of Weltmeister straps on my car. They lasted between three and four years and then they just sort of fell apart. They didn't break at first, they cracked all over and split in several places.

I have some elastic ties holding the airbox cover on right now.

[Bob Kontak]

Originally Posted by javadog

I think the root cause is people are having problems with poor quality straps.
JR

This has to be it. I would think longer would be better but there must be differences in the polymers and how they are cooked.

[notmytarga]

The measuring tape may tell us something. I think the straps are initially too short but do stretch with time.

Top Weltmeister strap is the strap which broke after three weeks.
The middle Weltmeister strap has been installed about 5 weeks.
Next is the newly arrived, never installed Weltmeister replacement from Pelican,
The bottom is a 4-10 year old strap - not sure if it is OEM or not.

The unused Weltmeister measures 300 mm from end to end. The black strap measures only a bit less than 300 mm between the holes and gives a reasonable fit when stretched easily to fit. The best measurement I got from peg to hook was about 320 mm.
Perhaps Weltmeister should consider making a longer strap - maybe they applied the 300mm figure to the wrong dimension. It was a workout getting the new strap into place. But looks good for the time being.