I recall reading in the archives that stainless steel inserts were available previously. But I don't recall if it was from a sponsor or member. I'll have to see if I can dig up that post.
The inserts need to be about 75mm deep (3 inches) and about 33mm in diameter. Using my advance math skills (πD), that means the other dimension is 33mm x 3.14 = 104 mm or 4 inches. At least for my 83QV, 6 or 7 inches is much too long.
THANKS FOR RESPONDING!!! I did the same arithmetic before asking & couldn't decide if the 3" dimension was intended to be PI x 1". Since quite a few posts had one or the other longer dimensions, I suspect the extra length is to provide a double thickness wrap which would provide higher outward spring tension to improve retaining the insert. If the tube ID is 33mm, then maybe the insert should be wrapped around a larger OD, say 40mm[1.5"] mandrel, it would be compressed when inserted, thus ensuring stronger retention. Hmm on 2nd thought I think some experimenting may be necessary to figure out the correct mandrel diameter as it probably won't stay at the mandrel's OD when released. I've tried following thru on several posts giving sources or links to sources. So far all of the links have been dead & the sources I called don't know what I'm talking about, probably because the posts were all several years old.
I suppose the double wrap might work. I've had my single wrap stainless steel in for 5,000 miles now without them moving at all. Another alternative is to bend out a 1/8" triangular tang on the two interior corners of the insert to grip the interior of the exhaust pipe. For me, the mandrel needed to be smaller as it sprung out a lot. As you note though, experimentation is best. The toughest part is rolling a true circlular tube; the start and finish want to stay flat rather than bend cooperatively into a circle.
I'm so happy I didn't read this thread before I put back the engine after rebuild. :-/ The air injection was removed and plugged with short plugs so of course it whistled. Trying to get my big muscular(fat) arms up over the front header to remove the old plugs and put in new, was interesting.... But now its quiet!
I just fabricated and installed exhaust tip sleeves in my 88.5 328... no more whistling! FWIW, I fabbed mine from 24 ga. stainless steel, wrapped around a 1" dowel, then formed individually around a 15/16" impact socket used as a dolly (O.D. 1.257"), with rubber-jaws in the vice and a rubber mallet and a small body hammer to form the part. My stainless steel blanks were 3.5" x 4.08". (4.08" formed the circumference) ... I formed them to just complete a circle, sprung them open to have about a 1/4" gap at the ends, and had to tap them into place, with a hammer and large diameter impact socket. Pics below. No more whistle! Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
I have a 308 that is whistling from the right side of the exhaust. It is driving me crazy. I just posted a thread about this last night not seeing this. I am going to try this out. Any chance you want to sell me two of these? My tools are limited. LOL!
How did you cut the stainless? I can get a sheet of 24g but not sure how to cut. Tin snips I'm thinking will mess up the edges. I have to do this ASAP. I took my 308 for a nice drive today and can't deal with the whistling one more second.
Caution: I'm not a commercial fabricator. I'm just a longtime automobile restorer, who wrenches on his own Ferrari.... So, these kinds of things for my cars are hand crafted - not machine made - and they are not perfect. That said, they certainly turned out just fine (to my standards of quality), and I wouldn't hesitate to leave them on my car when I show it. I cut the stainless with good quality straight snips. I did dress the cut ends with a grinding wheel, but only to remove burrs and sharp edges. I'd be happy to make a few of these to order, but the challenge will be getting them to exactly fit your pipe I.D.... I'd imagine they vary from car to car... I custom fit each one of mine, and all were just slightly different. I would think that a slight gap might be fine, and they certainly would still silence the chirping.... I'd probably position the gap at 12 o'clock, so it won't be visible. Can those of you who are interested in a set accurately measure the I.D. of your perforated pipes? I measured mine by finding the deep socket that just slip-fit into the pipe, then measuring the O.D. of that socket with a digital caliper. Mine was a loose fit to the O.D. of a 15/16" impact socket, which measured 1.257" O.D., and a 1" socket wouldn't fit, with an O.D. of 1.330"... So, I bet mine was about 1.30" (which led to a circumference of 4.08", which I used as my starting size.) I then ground them to fit after forming, so they would be snug in the pipe. It would also be smart to measure the length, which is easy to do by sticking a tape measure into the pipe and finding the inner end of the perforated tube, to measure the length - Mine was just under 3 1/2". I have a local supplier of the 24 ga 304 stainless steel... which made mine more difficult to form... Others on FChat have commented on using 26 ga. stock, which would be much easier to work, and pretty much anyone could make their own... Anyway, it took me about 3 hours to make a set of four for my car. I'd probably price them at about $15/each or $60/set. Anyone who's interested, please PM me, and we'll see what we can do.
Ferrari dealers used to sell those inserts as a kit -- I know because I bought a set when I still had my stock exhaust. Solved my problem the same way it solved yours. Simple fix.
I never got to bottom of mine. My mechanic thinks small leak in exhaust somewhere. Said they also breakdown over years and can make chirpy/whistly sound. Did yours have a chirpy sound when you let of gas?
Success!! Thanks to ZOOOOMZ for fabricating the inserts for me and sending them packed very securely. I inserted them, went for a test drive and now my car sounds like it should....a Ferrari not a VW Beetle.
Are you guys saying the whistle is coming form the 'tip inserts' with the holes in it? Do I understand -- cut them out, and weld in rolled sheet metal tubes? Any pics of this fab work? Thanks!
You don't even need to cut the perforated liners out or weld, just make the sleeves & drive them into place. See post #31 of this thread.
Very good! Thank you. I posted having not read into page 2 ---sorry. Yes - not a fan of the whistle. Anyone try HJS cats on the 308? Looks like a very nice quality component made in Germany. I've heard good things about them - Flow, and cleaning efficiency.
Here's another exhaust question: Anybody try the Superformance system w dual exhaust made to be used with cats? It says it's for a QV, but wondering if it can mount up on a GTSi without too much aggravation? Mounts look different. Would attach on cantilevered supports coming off tail pipes for GTSi. I like that this is polished stainless and must be a little lighter. Also, hoping it's not too loud. I didn't see one listed for the GTSi specifically. Image Unavailable, Please Login
For the air injector plug whistle, I still have a few sets with the longer tips. I can bring some to post in the US in 3 weeks if anyone needs some. $60/set. I tightened them in with a copper washer in place, marked the protrusion, ground off the marked ends, tightened them back in and just did a little grinding to blend them in (my heads were off and apart.) Using an index mark would work well. You could leave them in for a few hours driving, take them out, grind off the parts discoloured by the hot exhaust gases, and put them back. Image Unavailable, Please Login
