flynlo

As always, thanks Pete. Your hard work and expense lead me to purchasing Kline for my Spyder. And your continued curiosity keeps affirming my choice. It really does sound incredible in the Spyder. Also of note so I can add at least something….the exhaust does get “angrier” over time. While the tone and volume pretty much sounds perfect with the Kline, it started out somewhat “smooth” without much of a growl or a bark. Now it has that growl and also has some serious crackles and pops that weren’t as prolific when I first got the exhaust. Anyway, I am rarely just straight up satisfied when it comes to exhaust and always feel the need to improve something. I am here to say, I feel no need in that regard. It is damn near perfect. If I had it to do over again, I would save the money on the valve controller as I never use it. I would just cap off the vacuum lines and leave them open. It is amazing how this exhaust is a Jekyll and Hyde…..as it is perfectly civilized in the lower RPM range and flat out raucous when you get on the throttle. ANd as I type that, it is more of a load issue than an RPM issue.It can be loud in the lower range if your foot is into it….if that makes sense.

And TBH, I am VERY surprised to even think this…..because of this exhaust, I almost wish I had PDK. It gets so loud up top, I have a difficult time keeping my foot in it all the way to redline. It sounds like the damn engine is gonna come apart it is so loud and high pitched. With PDK I would get that perfect shift at the perfect RPM every time. I know. I know. That is the challenge of having a manual transmission. But I very often run with some GT3RS’s with absolutely nasty exhausts and to hear that PDK fire off those shifts is truly something to behold. Anyway, a close friend is getting his Spyder with PDK any day now. I will see if I am really missing anything. Because of what I am saying and nobody ever mentions this…This exhaust does somewhat “cure” the long gearing in this car. It obviously doesn’t change anything mechanically. But shifting well short of the redline is almost every bit as satisfying as shifting at the redline…almost…. So that is something different to think about.

Thanks again! After my salesman took a ride in my Spyder with Kline, he has sold at least 3 Kline exhausts. He was blown away. His words echoed by many others….”It now sounds like a proper GT car”! And it most certainly does!

Westcoast

I don't agree with this, or will say that on my Spyder there is an obvious difference between valves open and closed! I have Akra OAP's and the JCR silenced rear section, the difference in resonance and overall noise intrusion into the cabin is very different between to two settings.

TBH without the valves closed option the JCR silenced system would not be a very good system for those of us that want to be able to tame the exhaust note when the mood calls for it, cruising along, maybe listening to music or talking to your passenger. I find that in the valves closed mode and a light foot I can travel virtually undetected (from the exhaust note viewpoint), open up the valves and that changes profoundly..


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IL_Pete

This is a great post, thanks @flynlow! Some great points.

I agree that both Kline and the JCR are more throttle level sensitive versus RPM sensitive, with regards to volume. So as many have stated on a lot of the exhausts, even with the valves open all the time you can for the most part keep the volume levels decently low by just staying out of the throttle. That is what I do with the JCR when I am trying not to be too loud.

I agree with you that "fixing" the exhaust on the 4 718 4.0's really goes a long way to eliminate the long gearing frustration with these cars. With the stock exhaust and the maddening valve control operation, you really want to chase it up the RPMs all the time to keep it out of the less than 3800 RPM range at all times, and your brain gets focused on that in a negative and frustrated way. With the exhaust fixed, it is still pretty darn glorious to short shift well short of redline. You get a feel for what RPM you will be in in the next gear, to ensure you have enough torque to properly accelerate in that next gear. I have over 20,000 miles in my 2 4.0 Manuals over the past 15 months, so it is pretty much wired into my subconscious at this point, I really feel "one" with these cars in that regard.

I still am thinking about eventually doing the Deman 2-5 gearing change on the B25, not because the long gearing frustrates me - it really doesn't, but more so just because I think it would make the car even more lively and fun at lower (and more legal) speeds.

Thanks also for the comments on the PDK. Please do report your thoughts on comparing the Manual Spyder to the PDK Spyder, when you get a chance to compare.

I don't mind winding my RPMs out to redline. On spirited country road drives, I often do some pretty brisk 1st to 3rd or 4th accelerations from a stop, and run 1st and 2nd (in Mexico) to redline or very near redline, and then 3rd up into the higher RPMs, and then into 4th to settle/quiet down. I don't always have to look at the tach, I can tell by the combination of the sound and feel, and seeing the tach in my downward peripheral vision, I rarely hit the rev limiter (not very hard anyway), except perhaps sometimes in 1st trying to accelerate and navigate/rotate through a turn, trying to concentrate on too many things at once. (I use 1st versus 2nd to go through 90 degree turns, on spirited drives.)

Also sometimes I cruise in 3rd at 6000 plus RPMs for a while, and don't shift to 4th just because I think the wail sounds so amazing, it sounds and feels like the car is comfortable there. (Some of the farmers within a mile of me might not have the same appreciation for that as I do. ) The car just seems to say "is that all you got?" and asks for more punishment...

IL_Pete

Thanks for the post and contrarian view. Honestly I wonder if my valve controller is installed properly on the B25 - I seem to remember a little more difference between valves open all the time and PSE operation in the Cayman last year. I should have my shop take a look at that next week while it is in there.

tdlondon

Pete, thanks for the great time again, as always! We are definitely privileged being able to live so close and compare so many permutations of setups and car builds!

tdlondon

@flynlo I completely agree! My setup now has plugged vacuum lines for the valves. The Kline is able to be very civilized in low RPMs leaving the neighborhood and doesn't get "aggressive" until past ~2500 rpm. I am not adding a valve controller anymore. Maybe if I get tempted to put Kline headers on it... I might need to later.

UncleDude

I would describe the Soul valved exhaust (locked open) in the same terms. These both share an open x-pipe and importantly a muffler. I find it pretty civilized when applying the throttle gently.

IL_Pete

Okay, so before taking to the Dealer this morning, I troubleshot this over the weekend. I got the other remote for the Soul Controller and tried that. I think the battery was dead on the first one, the second one worked to shut the valves and make it quieter with the valves closed. I will have to experiment with that now to check out and experience that again, and how it sounds with the top up and the top down.

The JCR Exhaust didn't come in in time for this Service visit - it is missing in action in the UK and UPS is trying to track it down. So on this visit with regards to exhaust and sound, it will just be the Soul Resonated OAPs, plus the BMC Air Filters. Probably best to experience the changes one at a time anyway, but a PIA as I have to make multiple visits.

Westcoast

Thanks for the update, that sound more like it! I am on the road right now and find real value in being able to close the valves while cruising on the highway (speaking mainly of top up windows up), it doesn't reduce the resonance or volume to stock levels but it is significant when the resonators are in play!

Looking forward to your impressions!

IL_Pete

Yes, I agree. I did play with it some more, it does (as I recall from last year in the Cayman GTS 4.0) help both in low rpm tooling around when you want to turn it down a couple of notches, and for highway cruising in 5th or 6th under 3800 RPM. As you say, significantly louder than stock with valves closed, but still quieter than the JCR+OAP setup with valves open.

So a further update here - I did get the Soul Resonated OAPs installed, and the BMC Air Filters. I have to say, I am SHOCKED by the difference!

To refresh on the history here, I had the Cargraphic High Flow Filter OAPs, which to me were a great compromise / Goldilocks in between solution between the JCR Silenced Valve Exhaust and the Stock OAPs, and the JCR Exhaust with Wide-Open Soul OAPs, with regards to (1) volume, (2) bassiness in the cabin of a Cayman (not as much of an issue with the Boxster this year) and (3) power increase. The JCR with Stock OAPs was too quiet and lost a lot of power versus with Wide-Open OAPs, but had minimal bassiness in the cabin in the Cayman. With the Wide-Open OAPs, it was a little too loud for my tastes, but still not really that loud, if you compare to Headers for instance. I am bit sensitive to volume as (1) I don't want to be too obnoxious out there when driving in a spirited fashion and (2) I have an issue with a bad left ear that gets easily bothered by too much noise. The power was awesome, but with the Cayman there was too much Bassiness in the Cabin, it was too much for me in the daily driving around town where it is tougher to keep it out of the troubled RPM ranges. With the CG HFF OAPs, it was really great in the Cayman, I got a good portion of the power increase back, the volume was good, and the bassiness was livable.

When I got the Boxster and installed the same setup, I felt it was a little quiet for when the top is down, thus the desire to experiment some more. I figured that perhaps the Resonated Soul OAPs would be another good in between solution between JCR and Stock OAPs and JCR with Wide-Open OAPs like the CG HFF, but perhaps a little more towards the JCR with Wide-Open OAPs. But I wasn't sure, I was concerned that maybe it wouldn't be too much of a difference. Now of course I changed two things at once (to Soul Resonated OAPs and the BMC Air Filters), so when you do that you can't be 100% certain how much of the change was due to which one of the items changed.

I wasn't expecting much change from the Air Filters, so I was focused on how the OAPs would change it. The result was a SIGNIFICANT change, in tone, volume and power. Overall, the volume increased at all throttle and RPM levels. The sound under heavier throttle became much more aggressive, throatier, raspier (in a good way) and more Motorsport. The feel of the power increase a lot. Hard pulls were significantly more aggressive - I saw and felt the traction control kicking in a LOT more at high/full throttle in 1st and 2nd gear.

It almost seemed to me to have more power and more aggressive sound than the JCR with the Wide-Open OAPs last year in the Cayman. Tough to tell exactly, that was a long time ago, and also the cars react to the exhaust mods a little differently. That leads me to believe that perhaps the Air Filters do make a difference, maybe particularly when you open everything up with a freer flowing exhaust and OAPs.

The car is beastly now when pushed hard. So much so that you do get a bit of a feeling that you are overwhelming the chassis. More so than I ever felt in the Cayman - perhaps at those high levels of chassis stress I am feeling the difference in body stiffness between a Boxster GTS and a Cayman GTS. It doesn't feel bad, you are just conscious that you are pushing the chassis to the limits, that makes me think that you probably wouldn't want much more HP/Torque without going to a Spyder or a GT4.

The volume level for spirited country road driving is a little high for my sensitive left ear. I may have to wear an earplug for that. But also it does pretty much resolve the issue where the exhaust with the previous setup sounded a little too muffled with both windows up with the top down. It still does get just a slight bit muffled still, but MUCH less so, it is to me much more pleasant with the top down and both windows up.

Overall I am pretty happy with how this turned out. The only caveat to that is the volume and frequencies now being above the threshold where my bad left ear gets bothered. (My ear was doing better, it did get aggravated again separately from the driving by my dog barking right into my ear a couple of weeks ago, so it is tough to tell if it is just from the exhaust, or if it is more sensitive in general now.)

I can't comment on how the bassiness is with the Soul Resonated OAPs with the JCR, as it is not as much present in a Boxster versus the Cayman last year (it was pretty unbearable with the JCR + Wide-Open OAPs in the Cayman). I haven't experimented with the top up in the Boxster yet to see if I can detect a difference in that, I will try that soon. But overall it sounds great, more aggressive, and the butt dyno says a good boost in power with the combination of the Soul Resonated OAPs and the BMC Air Filters.

I do suspect that the Air Filters have a positive impact on tone/sound and power - I would recommend that very highly as a complement to exhaust and OAP mods.

SpydrGuy

Great writeup Pete. I've really enjoyed your exhaust experiments. Very interesting about the power increase. I would not expect air filters alone to be that noticeable.

If I can try to summarize, On a scale between the wide-open and the CG HFF OAPs, the volume and tone with Soul resonated OAPs falls much closer to the wide-open OAPs, but the volume is attenuated enough to make it acceptable as a daily driver, at least in a convertible. Correct? When you get a chance please comment on the 2K RPM bassiness top up/down with valves open/shut. That seems to be the only weak point of the JCR exhaust.

UncleDude

Good review Pete, you just had to change 2 things at once didn’t you lol….. hard to know what the effect is of those resonated OAP. How’s the resonance now with the top up in the dreaded 1800-2500 zone?

IL_Pete

I haven't heard many people raving about how great the Air Filter upgrade is. My theory is that once you free up the airflow with Exhaust + Open OAPs, then it makes a bigger difference. My setup has a more aggressive and throaty tone to it now that I haven't experienced before with any of the many combinations. I would describe it as more Motorsport, more manic.

Yes with regards to the above question. For me it is towards the top of the threshold of how much noise I am comfortable making, but again I don't think it is too loud compared to other systems like with Headers. I will try to get some A/B flybys sometime with @tdlondon with a comparison of the Spyder/Kline setup, with my Son filming. That make take me a while though, all three of us are pretty busy people.

Also I do still have the Non-Silenced JCR Valved Exhaust coming in, I want to try that as well. I am a little afraid, LOL!

Will do re top up with valves closed and open. I seem to be completely incapable of putting the top up when the sun is shining and the temps are nice.

Will report per above!

Yes, I am often doing that re 2 things at once, which does undermine the precision and clarity of these experiments and comparisons. If I were a DIY kind of guy, I would do things one at a time. But I am not, and these dealer/shop trips are so much work...

SpydrGuy

I don't blame you for keeping the top down all the time. If it's not raining, my top is always down on my Spyder.

It sounds like you're OK with the deep bass noise at 2K with the JCR and Soul resonated OAPs, at least with the top down. Did the Soul resonated OAPs make it worse than with the CG HFFs?

Will-i-am718

I’ve been really enjoying reading this whole thread. I have a 2022 Cayman GTS 4.0 MT which as of 6/14 has the SoulP resonated oap & BMC air filters. And on 6/17, the CG valve controller unit & the SS delete were done. I think it sounds a little deeper & throatier now with no additional bothersome drone in all rpm ranges with both VO & VC settings—granted these were all just minor changes but cumulatively, it seems to have made a significant difference. But, I feel like i need a little more volume. I’m considering adding the SoulP valved exhaust muffler which sounds great on Matt M’s YT review. Question: At this juncture, what other back boxes should i even consider? Kline (won’t fit the SoulP due to Kline’s proprietary system), Cargraphics (quality exhausts made in Germany but confusing 4 muffler options & not sure if the sound will be as robust as SoulP & JCR, or JCR (great motorsport sound but worried about fitment & also titanium’s potential for cracking since i plan to track it someday in the future). Or should i just stick with the SoulP back-box add-on? At the end of the warranty period, i will consider street headers & an ECU tune if that helps. Thanks gentlemen! Hope i didn’t go off on a tangent here.