JB911

The video of the Soul valved deletes with center delete was on the 991 forums but id say would sound the same on the 997 cars-
With the valves closed there is a notable difference in sound, but i guess the only way to find out is to get them and hear for yourself -maybe if someone made a valved side delete with small mufflers on the upper pipes, it would be an option to use with center delete.
Agency Power has a design with small muffler:
https://www.agencypower.com/agency-p...151444148.html

tasman

Dundon has a return if you don't like it policy

Mr. Adair

In regard to Dundon I had a very informative conversation with Jamie today. He couldn’t have been more friendly, helpful and knowledgeable in regard to all things Porsche exhaust systems. We talked 45 minutes, he answered every question and would have talked as long as I wanted. Impressive. I’ll try to summarize tomorrow 🏁

bweSteve

that is VERY impressive MA. 45 minutes can be forever when running a business. And for him to also spend all that time posting + Q&A about the harmonics. I love hearing things like that. Makes me feel as though our car industry is a small world, even though I know it is not.
Looking forward to hearing about it.
Dundon business is coming from my little garage soon, that's for sure. I'm also SmokiesGT so I'll be talking to them about that too.

JB911

The valved side delete + center delete, for those who already have one, is relatively inexpensive. There are quite a few choices for those who want a complete system designed to make power of course.
FVD/M&M catalog is so extensive with so many variants you could go crazy trying to decide on which one to get.
Whatever these rallye cars use sounds fantastic. I've tried to find out what they use and read over the years-some had M&M systems, but it seems like it's not readily available info. Some rallye cars are quieter and probably use Cup exhaust. This one looks like long tubes+wide open:

tasman

Jamie and Dundon are great

JB911

I started looking more into the valved deletes and noticed most are compatible between 997 and 991 with a few exceptions. I put a WTB listing in the marketplace, missed out on a few listings but hopefully someone has a set in good condition. Many have moved on to full systems or went back to stock to sell their cars. The main worry about a used set would be corrosion-recently I saw a stock exhaust up on a lift that had a lot of corrosion, car saw snow and salt up north-I also noticed some manufacturers switched to the bellows/flexible upper pipe design-easier to install I suppose, but I imagine they could corrode or crack easier(?)

Mr. Adair

Quick Update: I am pretty convinced the boys at Dundon (Jamie) will get my business. Based on engineering, lifetime warranty, knowledge and customer service. Their complete exhaust solutions are pretty enticing. If money wasn't an issue on this project I would probably would opt for their complete long tube, side delete and rear muffler set up. That is an 11K proposition however as their rear center muffler (two choices of loudness) is an additional 4K. I have gotten enough sketchy feedback on my Fabspeed headers and Center muffler that I believe I'm going to put my stock headers back on use Dundon's valved side deletes and my stock RS Ti center muffler and 100MM tips to start. According to Jamie (although I didn't understand his explanation) their side deletes valves do not have that on/off trait at 4,000 RPM that the stock side mufflers have, the exhaust loudness should seamlessly increase as the RPM's increase. He is confident that I can use OEM Ti center muffler without cracking based on results so far. I may down the road opt for their center bypass. Here is the link to the side deletes:

https://www.dundonmotorsports.com/pe...-only?carid=39

Any feedback chime in!

Modena 1

Curious to hear your feedback because I would also be into this.

So this would in theory reduce weight and heat and add maybe a little hp but no tune is required and will be a little louder but not as loud as a sharks bypass as an example.

Mr. Adair

Definitely no tune required. The 90lb weight reduction will be nice. Yes, in theory you need an OEM rear Center muffler ( Ti or Steel ) to add in more muffling to compensate for the removal of the side mufflers (which do a large percentage of the noise reduction) when you add the side deletes. Yes, kind of reverse of adding a Sharky bypass to get louder when using stock side mufflers. Jamie says it’s a really nice rich quality no drone sound that works at cruising speeds. Their side deletes evidently (not sure how or why) don’t throw as much heat and should not burn out the OEM center mufflers. For those of you that want to use their lifetime rear center muffler he recommends their “loud” version as the “quiet” version is really oriented to low decibel track requirements. Probably won’t be able to give feedback for at least a few months. I guess there is a car in town that is using this set up but I’m guessing his car is stored as it’s winter.

CT944

Why not leave the FabSpeed headers on? If they aren’t throwing a CEL, then I’d leave them alone and only replace with stock if they fail.

Mr. Adair

I am being told it’s a matter of time before they crack and that they are not really adding anything over stock? Been told that twice now. Again, not sure of this claim as these are often opinions based on preferences. And it’s probably the right time as the car will be at Chris Cervelli’s shop in CO getting other work done.

osu s2k

Has anyone tried a simple valved side delete like dundon or soul, And then use a Gt3 titanium muffler for the center, I’d like to know what the difference is in sound quality/volume With The above set up versus a center delete and stock side mufflers. The obvious weight advantage is very attractive to me but would it be too loud?

to update i read through the whole soul bypass pipe thread. Some Critical points are if you lose low rpm torque I’m less interested, are there any real world Dyno data out there other than like complete systems like Akrapović

Mr. Adair

That’s the set up I’m going to try. Dundon has quite a bit of real life data and claims some pretty good HP increase and flow increases by percentage on their site over stock. They certainly quantify their power numbers in house from what I can tell. They also have 2” and 3” rear center mufflers to work with stock exhaust size or their proprietary larger 3” on their long tube headers. But I agree with you I’d like to see what type of power it is. When messing around with Porsche Motorsports stuff it’s easy to go backwards if you don’t know what’s what. I would to see Jamie jump in and comment on this topic and thread but I know he’s a little salty still from a Rennlist debate a while back 😉

Mr. Adair

Small update: Just had a conversation with Paul at SOUL. Their valved side deletes are about $1100 less than Dundon. He is also willing to take the product back with a 10% re-stock if I can't find a combination I like. Nice price and offer. Has anybody used a SOUL product yet? Quality level? Any feedback welcome. Still trying suss these two out..