stepan1

Is anyone using the slip-on on their 4.0? How are you happy with it? Heard that the JCR tends to drone but it sounds so much better on vid compared to the Akrapovic!

I can only swap the back for warranty reasons (EU spec).

Thanks for the reply!

IL_Pete

I have the Silenced JCR now with the CG High Flow Filter OAPs, and I like that a lot (Cayman GTS 4.0). I don't think I am done experimenting yet, I plan to try some more things out next year when my 2022 Spyder comes in, and the Akrapovic Exhaust is on my list. I would pair it with the CG OAPs, which provide a lot of the benefits of an upgraded OAP with less drone and slightly less volume, and increased HP/Torque (at least according to my Butt Dyno ). BTW CG does make a monitored version of those OAPs for the EU.

Here are a couple of great videos from @rzspyder :

https://rennlist.com/forums/718-gts-...l#post17299706

I think both the JCR and Akrapovic sound great. I have not heard the Akrapovic in person yet, but based on the videos I would say the JCR is more "Motorsport", more Modern Porsche, versus the Akrapovic makes me think more so of the sounds you hear on classic Water-Cooled 911's, more raspy at high RPMs and less "modern" - like an Air-Cooled Restomodded 911 you would see on Petrolicious. A little less of the high pitched Motorsport wail that you get from the JCR (which is awesome and quite addicting!).

I have it in my head that perhaps for my Spyder, more of an "old school" tone like I hear from the Akrapovic in the videos might be a good fit for that car, versus the JCR tone for my Cayman GTS 4.0 fits the vibe of that car more...

IL_Pete

Also there is a lot of great data in this very large Group Buy thread, including comparisons to JCR, reviews and Videos/Clips.

https://rennlist.com/forums/718-gts-...group-buy.html

I am about 2/3 through it this morning over a few cups of coffee. Seems to be mixed reviews. Mostly posts of just OAPs or Exhaust plus OAPs, but not as many that I have seen with just the Exhaust as you are asking, @stepan1 .

Thanks for posting your question and inspiring me to go through these threads! I was looking for something 718 exhaust-related to do this morning on a cold rainy Sunday here in the Midwest US.

Kgoheen

I had the Akra slip on installed a few months ago on my GT4 and am very happy with it! IMO, the sound is greatly improved at all rpm ranges, no drone whatsoever. There is a significant weight savings as well. And the black tips - beautiful workmanship with an aggressive look. An outstanding aesthetic enhancement to the overall look of the car.

Larry Cable

This! I have the Akra with the Cargraphic flow optimized OAPs and I am very happy with the sound, I replaced my Soul OAPs with the cargraphic because I fiund the straight thru OAP resulted in a SHOUTY sound with some
drone ...

IL_Pete

Larry, I owe you one!! Your report is the reason I ordered the Cargraphics High Flow Filter OAPs (also from Eric at Supreme Power), to get that "Goldilocks" solution between the Stock OAPs and a complete OPF delete OAP. Louder than Stock, not as loud as full OPF delete, and less drone and bassiness than full OPF delete with my JCR Silenced exhaust, only slightly more than with Stock OAPs. And most importantly for what I was looking for, increased HP/Torque (butt dyno measurement only) versus stock, feels like almost just as much as with OPF delete, for increased pull over 5K RPM.

It worked perfectly for exactly what I was looking for and hoping for, thank you!

I might try them with the Akrapovic Exhaust as well, just for the fun of comparing versus the JCR. I need something to keep me busy until my Spyder comes in...

MechEngr1287

I would really love to find someone who has done the Dundon Header setup in conjunction with the Akra exhaust!

Larry Cable

glad to help! BTW I "suspect" that all straight thru OAPs will result in some drone ... I just got tired of the sound level when just cruising along people on freeways were looking at me when I passed them by! -
I do wonder what the difference is between OEM OAP and the CG optimized flow ... I even wonder how the CG OAP w/o the optimized flow would sound like!

Another "thought" I have is by duplicating the OEM design the Akra slipon "side" cans also integrate nicely into the underside of the car and smooth out the airflow ...

MechEngr1287

I 100% agree with this as well. I wonder to what extent the underbody airflow is effected with exhaust designs that now leave a lot of that area as open cavity

Larry Cable

my thoughts exactly!!! - particularly for the Spyder where the diffuser is responsible for the vast majority of downforce vs the "wing"

jmartpr

I did...it sucks!
Any muffler that dumps each bank independently (like Akra) will sound very un-Porsche...you need a muffler that mixes both banks, valves open or closed.

MechEngr1287

Makes sense but damn that sucks.. This was my fear but glad someone else is confirming it. I know Dundon was working on a muffler solution around end of last year but havent seen any updates on the interweb. I hope they come out with one at some point in near future

dnimi123

THIS^. Akra is not an x-pipe set up so the sound you get is just low and more volume. I have Kline inconel and really love it. Kline should be on everyones short list for the GT4/Spyder!

Regul8415

Are you still running this set up? I currently run Dundon headers and debating if I’d wanna add mufflers to the mix but not sure which ones.

998R

JCR for me.

Cheers,
Harry.