Exactly, Tesla is also made in USA, and their quality...

 

Unfortunately, we are not what we once were in terms of manufacturing. I live in an area that was once a great manufacturing hotbed. SC Johnson, Dremel, Modine, Case (Now Case New Holland), Twin Disc, Insinkerator, etc. just to name a few all started here. Malted Milk was invented here, as was the garbage disposal. One of the first automobiles was also assembled here. The point is, manufacturing used to be a great part of this country and especially in the area I come from. It's a shell of itself. Every year, we lose more and more companies. We have some tool manufacturers left, but they have a foot in the grave. It's sad to see honestly.

Rant over.

 

Thanks for your post. I bought the wires since I had the car but never used them as I did not like the sub 4k sport exhaust drone, and I find the sound above 4k loud enough. Sorry if I am asking a daft question in my ignorance, from what I
understand in your description the clamp keeps the valve 30% open when it is supposed to be closed under 4k. Above 4k with sport exhaust on does it also keep the valve 30% open only?

 

The clamps can keep the valves open to whatever percentage you would like them to be under 4k rpm. OP just likes them around that level, due to noise and drone. After 4k rpm, PSE kicks in and fully opens the valves.

 

That's correct! With PSE ON, the Valves are OPEN until about 1800 rpm, then they close until about 3800 rpm when they open again. The Collar prevents the valve from fully closing in the 1800 ~ 3800 rpm range. By moving the Collar on the Vacuum Solenoid Shaft, you set the amount the Exhaust Valve stays open. Thus, it's adjustable to your desire sound level.

I'm still playing with it, as it's really easy to adjust once the collars are installed. I've opened them up a little more and started measuring their position. Currently 3/8" from bottom of collar to the step diameter in the shaft...... maybe I'm getting used to the higher volume

 

Thanks for the clarifications. Another daft question, would wiring one of the two valves , without collar, half the drone? Equiv to wiring both sides and setting both collars to 50%?

 

A few weeks ago I ordered several sets of split collars from Amazon, with the same idea to control the exhaust valves as @981KMAN . I received two of the split collar sets pretty quickly (the AZSSMUK and Sinoblu versions), but the 3rd was delayed so I hadn't permanently installed any of them yet...just a quick test fitting. Needless to say, the quality of the parts received from Amazon were lacking (especially the ones from AZSSMUK), with some of the split collars not coming close to lining up. Easily caught if there was any visual QA on the parts.

Then I read the response above suggesting McMaster-Carr (thanks @unclemat ), so I proceeded to order two sets of those for comparison: a pricier 316 Stainless Steel version with 6 mm shaft diameter, 16 mm outer diameter, 9 mm thickness (p/n 9652T14); and a much more reasonably-priced version made out of 303 Stainless Steel, 1/4" (6.35mm) shaft diameter, 11/16" (17.5mm) outer diameter, 5/16" (8mm) thickness (p/n 6436K32). I'm afraid that the outer diameter might be too large on the second one to clear the studs that extend down from the valve body, but once the weather warms up here in eastern PA I can do some test fittings to find out (probably this weekend).

It's worth mentioning that the quality of the parts from McMaster-Carr is FAR superior to the parts I received from Amazon. So if you are going to use the split collars to limit the exhaust valve closure, it's absolutely worth getting the parts from McMaster, imho! And they delivered the next day for the $8 shipping charge! One final note for people attempting this: if you order a metric split collar (like the first P/N I listed), you will need a 2.5mm hex key to tighten them. If you order an English/SAE split collar (like the second P/N), you will need a 3/32 hex key to tighten them.

Here's what I've ordered so far; will post back once I do a test-fitting with the McMaster units. Currently my exhaust valves are wired open, which is great for hooning around but a bit too loud for my tastes for day-to-day driving. Curse Porsche for not giving us simple On/Off control over those exhaust valves!

 

I wouldn't recommend risking it since it doesn't provide a clear advantage but may have a significant disadvantage.
It is unlikely that the ECU would properly handle the different back pressures on the left vs right cylinder banks. It would likely get different readings from the O2 sensors on each side and could throw a code - although I'm not at all sure if that would happen.

 

you also might get some weird vibrations…. I know the soul unit on my car definitely translates more vibrations into my seat and hands

 

following, might be a future mod

 

Following in the footsteps of @981KMAN , @unclemat and @slilley above, I went ahead and "splurged" to get the McMaster's 316 stainless steel 2 piece clamp and switched out the wiring solution I did earlier. I worried a little about other clamps possibly getting some corrosion on the threads eventually and make them hard to remove or adjust.

Thanks for the recommendations! Cost shipped was $75 and they arrived quickly. Here's a couple of photos.

I like this approach much better than the wire. I've also followed the recommendation of allowing the valves to close just a tad. Surprisingly it does seem to reduce the drone with even just the little bit of closure but still keeps a better sound overall. Additionally, back in my early 911 days I was also aware that disabling the valve movement completely could eventually result in them getting sticky when someone would try to reactivate that... so I guess a little movement should help prevent that.

 

StormRune , Great Job. Looks Perfect!

I have been playing with the amount of valve closure and after a few adjustments, have it set just right for my liking. I no longer have the very noticeable drop in volume between ~1800 - 3800rpm, and the exhaust volume is perfect for driving around town & leisurely county roads.

I'm really glad to see others having success with this easy and adjustable "cheap exhaust valve mod"

 

I should probably pick up a set before there is national split colar shortage

<--- hoping to get the car in summer

 

I just did the split-collar installation this afternoon, but I wasn't happy with the results. When the valves close, I could clearly hear the "cloink" of the metal-on-metal contact when the valve plunger closed. That exhaust valve opens and closes often when you are in Sport Mode and lumbering around town. Seems like I'd have to add a layer of felt to either the collar or the valve mechanism in order to soften that metal thud. And at that point, it's no longer a permanent fix.

@981KMAN and @StormRune do you hear this happening, or is it just my overly-sensitive ears?

After I removed the collars, I thought that maybe I was over-thinking this problem - looking for things that aren't a problem, except in my twisted mind - and that maybe the stock valves weren't that bad after all. I had been driving around for about the last 3 weeks (including one track day) with the exhaust valves wired open, so I had forgotten how incredibly ANNOYING the stock valve behavior is! That transition from quiet to loud at about 4K is just horrible. And yet, that's where you spend a lot of time when you are hustling around on back roads and taking empty exit ramps at 3x the posted speed limit.

So, I'm back to wiring open the exhaust valves full-time, and considering a Softronic tune just to get the exhaust valve programming the way it should have been from the factory. I don't even want a different tune than what the stock Porsche tune is (i.e. no 200rpm change in redline, as Softronic offers as an option). I just want the ability to decide how the exhaust valves should act, plus it'll be nice not to have to manually disable Cylinder Deactivation and Auto Start/Stop.

Install tips for anyone who's going to do the collar install: In order to guarantee that the collars are in the same location on both sides of the exhaust, I used a spare split-collar-half that I slid in between the bottom of the plunger and the collar I was installing (that allowed the valve to close about 50% of the way). Also, don't bother raising the car more than 3-5" inches when doing this work. I had the rear of my car up on 10" Race Ramps, and that put everything just far enough away from me that I was struggling to see with my aging eyes (even with good LED lighting from all sides). Lastly, when I removed the collars, and was surprised about how easy they unscrewed after just a short ride. I had tightened them down enough that I was worried about damaging the plunger with my twisting force. So maybe some Locktite Blue might be a good addition.

I'm back to picture-frame wire to keep mine open all the time.

 

From what I can see, you could just use this collar to prevent the valves closing at all instead of disconnecting the vacuum lines or inserting a grub screw.

Edit: Meant closing not opening