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I am not using a stock muffler. I have a SS GHL muffler that has a nice sound for normal driving.
I'm very satisfied with that side of the "sound" equation here.
This whole thread has been about the sound coming out of the wastegate side,... when on boost.
Thanks for continuing to help me come up with ideas
This whole thread has been about the sound coming out of the wastegate side,... when on boost.
When you solve that one you let me know
With my twin wastegates, my car sounds like a kazoo on boost. Not that it sounded great with the single either.
a couple months have passed, and I have an update to this thread...
I was able to find another LH wastegate side exhaust tip,... one that I am willing to modify (gut the baffle out). I will keep the other 1991 datecode stamped tip for Concours & Originality (along with the rest of my original full exhaust setup). I'll probably end up swapping back & forth depending on how/why/where I'm driving it.
So the answer is YES, it definitely makes a difference in the sound. I am BACK to having that throaty exhaust note during open wastegate / WOT. Psyched about that!!
It was very simple to take the baffle out of the LH tip. AND I was able to preserve the "look" of the tip from the rear (ie, you can still see the smaller hole plate just inside the outer oval)
When taking the baffle out, I also cut the inner small tube down, so that the gasses do not tumble around inside the tip. It is more of a straight out exit.
Paul, I hope this helps you get a feel for what I did. But I doubt it is comparable, since your setup is completely different.
Pics below to show you how it came out. Compare to my pics in post #1 (for what it looked like before I started)
When installed, you cannot even tell the baffle has been removed....
Just the tip. And it was a NON date coded Tip from 1991 too.
It was important to me NOT to modify my original exhaust tip that has the date code from 1991. That is sitting up on my garage shelf with all my other original exhaust parts.
And since my goal was to get back the sound that I had with the GHL round straight-thru tip (or hopefully even better sound),... let me also report-out on the affect that it had..... = not much. I was a bit disappointed that it still did not give me that loud growl I wanted to get back. I think it has to do with that WG side tip, since it has that extra plate just on the inside (shown in 1st pic above), that has another smaller hole that the exhaust comes out. It must force the exhaust to tumble inside the tip before it flows to the outside, and stifles the sound.
Sooooo,... my next step was attempt to find another Cat that I could gut. But no luck there. I looked for about a year. It did not surprise me though, that I could not find one,.. since, according to Gabriel / Franz, there were only 580 sold in the US in 1991 (plus 33 in Canada), and in 1992 only 233 in US + 15 in Canada. So between the two years, only (613 + 248) 861 total that might be a source for an original Cat. no go there.
So it is ironic that you are asking me this question right now,... because just a week ago, I installed a replacement pipe for that WG cat. Although with such crappy weather & busy schedule, I have not yet taken it out to see how it sounds WOT.
What's your plan & why? Going for HP? or Sound?.... or both?
=Steve
Well since a judge probably cannot tell that the WG cat is gutted - couldn't you still gut the one you have - enjoy the sound without getting penalized? Easy for me to say because I run a gutted one but have an original one on the shelf....
heliolps2 can do whatever he pleases. I was just explaining the thought & execution process that unfolded for me. I'm happy with the choices I made, and that I've kept original date coded parts intact.
I hope with this nice weather that I get a chance to test out my new pipe, and get the sound I'm looking for.
... and yes, all changes I've made really cannot be detected by judging, nor did it have anything to do with that.
My choices had more to do with returning the car to exact originality,.. if I ever chose to do so.
My choices had more to do with returning the car to exact originality,.. if I ever chose to do so.
A wise man told me years ago that the Corvette world was divided into two camps; those who wanted every fastener to be stock and those who modded every inch for the car for improved performance.
Apparently the Porsche world is no different.
heliolps2 can do whatever he pleases. I was just explaining the thought & execution process that unfolded for me. I'm happy with the choices I made, and that I've kept original date coded parts intact.
I hope with this nice weather that I get a chance to test out my new pipe, and get the sound I'm looking for.
... and yes, all changes I've made really cannot be detected by judging, nor did it have anything to do with that.
My choices had more to do with returning the car to exact originality,.. if I ever chose to do so.
=Steve
What's the reason for a cat on the WG anyway ? even if I gut WG cat and I move back to California the smog sniffer would not be used on that side. and it would pass a visual inspection.
I would gut it for the sound, but if I ever go to sell it, It would be hard to find a stock replacement WG cat. And that's what's holding me back from gutting it.
Originally Posted by Metal Guru
A wise man told me years ago that the Corvette world was divided into two camps; those who wanted every fastener to be stock and those who modded every inch for the car for improved performance.
Apparently the Porsche world is no different.
I had a highly modified Turbo 23 years, and that was cool, Now I like the stock look with light mod's that can be hidden and easily changed back to stock. partly because of its value.
Would someone see this mod as something that would devalue the 965 ?
Here is my take on this. I was one of the odd ones who believed back in 2003 that these cars would be worth more than MSRP someday. Although everyone thought I was out of my mind. I decided back then that despite my desire to modify my car I always felt keeping all the original parts and making only bolt on mods was the right path. I have nearly every original part right down to the orange side markers. These parts are always available and interchangeable but something to me about retaining the parts that came on the car from the factory was most important.
I never purchased the car as an investment. It was more about lust over what I thought was one of the nicest looking Porsche's and sexiest cars ever made to date. Not to mention the unique driving experience.
There was a time you could pick up these cats for pennies and I wish I purchased others. I actually picked up a 94 complete exhaust and sold it for 10 times as much as I paid. Everyone thought I was nuts for spending the $$$ to begin with. Wish I purchased more along with the numerous 3.3 and 3.6 EZ69 units I saw sell for less than $500 each.
How many sets of speedlines did I buy and sell and wish I kept all of these parts as they have increased in value almost more than the cars themselves.
In your case it is unclear. You have done a masterful job returning the car to stock. The one big ? is what will a non matching numbers car bring in the future? I have no doubt it will still bring strong money but it may or may not impact value to some degree. I wouldn't worry about having a gutted WG cat. Although if it is that important keep your eyes open for a used fabspeed or FVD bypass. They put a cat on the WG for both noise and EPA regulations. The earlier 930's had a dump pipe so I can't see this impacting the value all that much although it doesn't hurt to have an original part on hand. AFAIK the cat along with the tip are not date coded. In fact my car came from the factory with polished tips vs black. Here are pics of my tip and unless there is a code I am not aware of this should fit any 964 turbo. I have the tech art turbo S style tips on my car and I have never tried the car with the factory tip and gutted cat so I can't say if it makes much of a difference in sound. In either case you can always try it and if it isn't loud enough go and gut the tip as well.
I am curious if anyone knows? I believe the 2 Q 92 means second quarter of the year 92 but I am not sure. I do know the heater boxes and main cat have date codes on them and would be dated 1992 or 1993 for the 94 turbo.
BTW the tip and cat are still available from Porsche only $437 and $1700 or so each. I think I paid $150 or so at one time for the cat used. Times have changed.
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I am curious if anyone knows? I believe the 2 Q 92 means second quarter of the year 92 but I am not sure. I do know the heater boxes and main cat have date codes on them and would be dated 1992 or 1993 for the 94 turbo.
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Yes that is the date code. My Tips are Q1 of 1991.
I agree with everything else Cobalt. Plus I agree that for a few bucks, why not "play" with a aftermarket cat-bypass & stick the original Cat on the shelf. As you say they are HARD to find any more,...
well that's good news,..... but damn I still have not even had time to take mine out & listen to the improvements!! And it was a beautiful weekend too.
too many house maintenance projects before it starts getting cold.
09-16-2015, 12:51 PM
