StormRune

Another note. My son and I just did a test where he left me at the side of the road and he took off at WOT, then another at a normal level of acceleration. This was the first time I heard the exhaust from outside the car on the road.

Dang! I certainly won't be doing any WOT driving around any residential areas!!! (Of course, I typically didn't do that before either). The video just doesn't communicate the power and sound that comes through with this when it is set to Loud. It is very nice though. Loud is okay at more conservative throttle levels though, but even then the more conservative side of me probably won't do a lot of that when actually in the neighborhoods. The improvement in the "normal" exhaust sound is just fine for that.

falco1098

Sounds really awesome

That new BRAP in the upshift is bitchin!

Congrats.

Soul Performance

Shawn, I sent you a PM

Words cannot express our gratitude for all of the kind regards and support Rennlist has shown to our company!

On behalf of the entire team, we all look forward to being a part of and assisting the Rennlist community in the future.

jwerley

I truly after a couple months now cannot say enough how much I love this exhaust setup. My favorite picture of their exhaust on my car is this one...I might drive around with the PSE turned on all the time.

StormRune

Okay, I have one more interesting comparison and I'm done. (I'm between contracts so I clearly have too much free time!)

Overview
Last week I also picked up a Waylens, a dash cam specifically targeted to performance driving. I used its Performance Mode to do some tests before and after the exhaust change.

So here's the interesting part. I'm actually seeing a repeatable/measurable performance gain, which to be honest, is something I didn't really expect to happen.

I was too cheap to pay for a before/after dyno and I figured the real proof of a performance change would show up in real-world performance tests. And amazingly it did!

First, let me say that overall I'm a bit disappointed in the 0-60 numbers I'm getting from my car according to the Waylens... I'm hoping it is pessimistic or it is partially due to the high temperatures and high humidity current here in Texas. The pavement of the safe/untraveled section of road I was using wasn't the best either, but it was the safest and flattest place in the area I could think of to do this. The car actually seems to hook up okay. All of the runs were in the same location in the same direction. The temperare was a little different, 95 degrees for the PSE and 83 for the Soul, but that would only explain a tiny part of the difference, a few hundredths by my calculations of air density changes and estimating the possible effects of that.

The Waylens uses a 10hz high-resolution GPS and a 10-hz OBD-II dongle along with onboard acceleration sensors to come up with its results so I think it is about as reliable as you can get short of much more expensive equipment. If anything, it is consistent within itself.

Results
In the before runs, the 3 best runs all were within 0.10 seconds of each other and resulted in a best 0-30 of 1.77 seconds and a best 0-60 of 4.54 seconds (4.54, 4.60, 4.64).
In the after runs, the 3 best runs all were within 0.02 seconds of each other and resulted in a best 0-30 of 1.72 seconds and a best 0-60 of 4.31 seconds (4.31, 4.32, 4.33).

The videos also include the audio from its mike and the windows are down in the tests, so you can get a good idea of the in-cockpit sound change if you play them back-to-back. The mike still doesn't do the sounds justice in either case, but you can certainly hear the difference.

Videos
Stock PSE: Soul Performance:
And for those wondering why I'm doing this (as per a PM'ed question): If you've seen my posts on the 997 and 991 forums over the years here you'll see that I like real data, I like nicely done products (Porsche!), and I like to be analytical in answering questions. Its related to my nature, my job until recently was the Technical Director for a company doing crazy research stuff for DARPA and others. Now I do those things under contract. Yes I had to purchase this system just like everyone else, but I did take advantage of the Rennlist member discount offer they posted on the forums a few weeks ago. And No, I have no relationship with Soul or the people that work there.

Soul Performance

Wow StormRune! Really great and incredibly valubale data. Can you comment on how that set up worked compared to say a V-Box? I am not sure if you have used a V-box but I am learning that if I want to hear a review on something, you're the right guy to go to!

We were also greeted with a great surprise yesterday when jwerley stopped by with the 991. Always a pleasure to hear from clients and we jumped on the opportunity to shoot some more video. Take a look and let us know what you think!

StormRune

Thanks Evan. I've just gotten a high-frequency/high-accuracy GPS unit (SkyPro XGPS160) and I've had a ObdLink MX high frequency ODB-II unit for a while, both are preferred with Harry's Lap Timer and should allow for some quality data capture. The Waylens is also made with just that in mind along with better quality integrated video. I'm probably autocrossing this Sunday and I'll do some tests with both that and the Waylens while there to see how they do. I'll post something about them after that. I considered the VBox units but thought that these might work as well or even better for me at a lower cost.

Wow, your video capture is much better than mine... beyond even the really clever icons at the bottom! I thoroughly recognize those sounds. Nicely done!!!

jwerley, thank you for sharing and helping better document these great sounds. Beautiful car too!

sechsgang

Focus on the cat back 100 percent. Headers make such a small, SMALL difference on an NA car like the 991.1 it's ridiculous. The 991.2 however being turbo is a little bit different of a story if you're willing to go through he development costs. Granted it's REALLY hard to beat porsche's from the factory on that one...and tell Spock I heart him lots.

TSOS

thats interesting about the headers on the 991.1. I was truly torn on if I should get them. I ended up not getting the catless headers since I was really looking for performance since the Soul exhaust already sounded great. My exhaust is going on in the next few weeks and I'll post my findings.

Johnny5Alive

I don't think so. I have a boss 302 that picked up measurable significant gains from headers and tune to optimize them. Kooks headers, and I went with shorties to keep the factory cats. Long tubes would have resulted in even more gains. The car didn't pick up hardly anything from changes made after the cats. That car is NA. The kooks resulted in somewhere around 18 rwhp gains.

If I had to guess, I would guess that headers will result in more gains than changing the mufflers. My experience with headers is they don't really increase exhaust sounds, and the sound is mostly tuned by the end pipes of the system, mufflers and corresponding plumbing at the end. The headers change the tone so to speak, but every time I've changed headers on a car, the performance gains are real.

Overall, on my Boss 302, not a porsche, but still an NA platform, I changed the axle back of the system to corsa mufflers and opened up the side pipes first. There was next to no gain but the sound improvement was amazing. Later, when changing the headers, there was little sound difference, perhaps more bark. But the responsiveness and performance gain was real.

I don't think we have enough data, save for what claims we've seen from companies selling their headers about real gains on this car. Of course independent tests would be better, but it all depends on how well the headers flow from the factory. Not all NA exhaust systems are the same.

StormRune

I finally edited and pushed the installation video up to YouTube. In all honesty the printed instructions Soul provides are very nice and should get you there, but hopefully this will help people understand what they are getting into beforehand. This is a very DIY thing, especially if you don't end up with stuck hardware on the OEM exhaust like I had to deal with in the removal video. You don't have to remove the bumper and heat shield since everything is accessible from below without too much trouble.

Let me know if anything isn't clear or if you have any suggestions or comments.

Removal (posted yesterday in another thread for those that already saw that)

Installation

StormRune

One other note: I dropped by the local Lexus dealer this morning to discuss something with a guy I know there. I mentioned the new exhaust and asked me to go out to show it to him; then he had me rev it up some.

This brought out some guys from the shop when they heard the siren song of the exhaust note. They had a bunch of big smiles on their faces and asked for a few more. It was nice to share it with some car nerds! I also got some big compliments on the HRE P101s too. It's a good life

Soul Performance

StormRune, thank you again for the wealth of information and content you are providing all of us. It's a true pleasure to have you in the family. We're glad you're enjoying your system and all that attention!
-Mike

sechsgang

It's more about the quality porsche puts in their headers vs what ford does OEM. Porsche literally makes some of the best headers in the business quality wise and they are really built to last. I'm not saying you can't get another MAYBE 4 hp out by doing them but thats a lot of expense for not too much return. The sound does change a LITTLE but really that stuff comes from less restrictive cats (or none) and changing the muffler or a combo of the two. You also mentioned a tune...which for a ford V8 really is where most of the real HP is picked up and often simpler than doing the same to a flat 6 Porsche motor. Id wager even with a tune and headers back, you're talking MAYBE 20-27 hp on a NA Porsche when all is said and done. And that's about 10k worth of work and junk to get there and your warranty pretty much out the door should something happen due to the tune (granted it does matter what dealer you have but if something bad happens, it's not terribly hard for Porsche to find out something has been changed).

Johnny5Alive

Do we know this for sure? I don't see very many threads where 991s have had headers swapped and dynoed to test for results.

On many other cars, headers have real documented results.

The only documented tests, Magicrat on this very board saw significant gains with Fabspeed headers and has documented Dyno tested results to show it.

I don't believe that Porsche has left nothing to be improved with headers. They build to cost, sound, and environmental standards for the average consumer. Otherwise magicrat wouldn't have found such an improvement and his/her car is a GTS powerkitted car.