Akrapovic Slip-on (rear section) exhaust - 718 GT4 - Page 2 - Boxster/Cayman - PistonHeads UK

I'm considering fitting an Akrapovic slip-on exhaust to my 718 GT4 and was wondering whether anyone on here has done this or knows of anyone in the UK who has done this? Ideally I would love to hear the tone of the exhaust in person hence the ask. I've had Akrapovic exhausts on two of my previous cars and have been very impressed with the sound and build quality.

Out of interest, how much are they quoting for that?

Looks like it could be nearly £6k including end tips https://www.design911shop.com/Akrapovic-Slip-On-Ra...

MPorsche said: Out of interest, how much are they quoting for that? As Twinfan mentions it retails around £5800 including the tips. I'm hoping I would be able to get a little off that and free fitting as I did with my previous Akra exhausts. Just need to hear one in person really and then make a decision.

Using their discount code brings it down to the bargain price of £5,098!

RichieRichie said: Using their discount code brings it down to the bargain price of £5,098! That's good to know. An expensive bit of kit but a good chunk is recouped when you sell it on.

I’ve not taken delivery of mine yet but have been watching countless videos on YouTube as have had Covid so been house bound and I watched one last night where they had fitted the car graphic valve controller and I thought for approx £500 it was a great improvement and worth a try and a tenth of the price of the exhaust upgrade. Thoughts anyone?

RichieRichie said: I’ve not taken delivery of mine yet but have been watching countless videos on YouTube as have had Covid so been house bound and I watched one last night where they had fitted the car graphic valve controller and I thought for approx £500 it was a great improvement and worth a try and a tenth of the price of the exhaust upgrade. Thoughts anyone? People say that’s the first thing you should do, it’s allows you to open the valves all the time. I have just gone straight into a JCR, update to follow..

RichieRichie said: I’ve not taken delivery of mine yet but have been watching countless videos on YouTube as have had Covid so been house bound and I watched one last night where they had fitted the car graphic valve controller and I thought for approx £500 it was a great improvement and worth a try and a tenth of the price of the exhaust upgrade. Thoughts anyone? I have the Sportec valve controller fitted (will be similar to the Car Graphic one) and it definitely makes a big difference. I leave the valves open all the time and I find it fine at all revs (I'm used to much louder cars). As you drive the car, the GPF loses some of its sound deadening, so the car does sound better with miles. I'd fit a valve controller first, and see how you feel with the car after 5k miles. If it's still too subdued, put another exhaust on it.

Valve controllers don't solve the "issue" of the exhaust banks not mixing on exit - the stock exhaust basically gives you two 3-cylinder engines not a single six. All you get is a louder version of the stock exhaust which isn't exactly laden with tone. You need an x-pipe aftermarket exhaust for the classic flat six sound.

I have the cargraphic controller, brilliant little cheat for £400, I only switch it off when on the motorway to stop the drone. Without a valve controller any back box will close it valves under under about 3500 revs. The Akrapovic is very nice but not worth the money in my book, and relatively speaking all the quality brands will be worth a good proportion of their value if you came to sell it. JCR or Cargraphic would be my choice.

MPorsche said: People say that’s the first thing you should do, it’s allows you to open the valves all the time. I have just gone straight into a JCR, update to follow.. Look forward to the update, is the JCR option c6k?

Bedlamater said: I have the cargraphic controller, brilliant little cheat for £400, I only switch it off when on the motorway to stop the drone. Without a valve controller any back box will close it valves under under about 3500 revs. The Akrapovic is very nice but not worth the money in my book, and relatively speaking all the quality brands will be worth a good proportion of their value if you came to sell it. JCR or Cargraphic would be my choice. Did you manage to fit it yourself or did you get a specialist to install. Would have thought an electrical engineer could fix?

I actually had PARR install it, I have a tendency to break stuff.

MPorsche said: People say that’s the first thing you should do, it’s allows you to open the valves all the time. I have just gone straight into a JCR, update to follow.. Have you seen this? Quite long winded but basically he praises the sound and weight saving but actually loses power and has drone. On the install video he did he mentioned the quality of fitment wasn't where he expected it to be given the price. It's put me off JCR a little. https://www.youtube.com/watch?v=fgX-XTOMaqI&t=...

Not watched the video but I have spoke to the guy. He did the dyno 2 weeks apart. Not a fair test, humidity etc

https://rennlist.com/forums/718-gts-4-0-gt4-spyder... Much more on here. Not sure his tests are totally valid tbh.

anonymous said: [redacted] I think he means a cross pipe design.

ScottyM4CP said: MPorsche said: People say that’s the first thing you should do, it’s allows you to open the valves all the time. I have just gone straight into a JCR, update to follow.. Have you seen this? Quite long winded but basically he praises the sound and weight saving but actually loses power and has drone. On the install video he did he mentioned the quality of fitment wasn't where he expected it to be given the price. It's put me off JCR a little. https://www.youtube.com/watch?v=fgX-XTOMaqI&t=... MPorsche said: https://rennlist.com/forums/718-gts-4-0-gt4-spyder... Much more on here. Not sure his tests are totally valid tbh. Reality is that, rear box swap should not be considered a power upgrade, it is a sound modification. And as has been mentioned, the runs by that RennLister are pretty questionable, and really show a lack of understanding. Personally, beyond a valve controller to open up the low revs on demand at the touch of a button… I’m not sure i would bother with anything else, from a value for money POV, unless I was changing out the system for a full system in search of power, and then you do want to ensure the system has characteristics like, long tube, x-pipe, etc, etc. Edited by TDT on Thursday 7th October 09:44

To get the flat six sound… gasses from both banks should be merged… one way to do this is via merge/x-pipe design, example highlighted

^ what TDT said Lots of variations out there, do your research before buying. Unlike TDT's thoughts, I've found changing the sound via an x-pipe design is worth doing for the aural benefit alone rather than doing it for power gains.

TDT said: Having an x-pipe design on the open path give you back your flat six sound. Not all replacement exhausts do this, and not all do it on the closed side too. Some good info in these two videos:

Here is a pretty good video, where John Gaydos representing Soul performance puts a scope into the stock 718 4.0 rear box to show what’s inside. Valves closed gasses from both sides do actually come together, but they are not flowed together like an x-pipe design. They just diffuse together in the big chamber through some internal grating. This clip though shows valves open it’s pretty much straight out either side. Having an x-pipe design on the open path give you back your flat six sound. Edited by TDT on Thursday 7th October 10:49