718 Gt4 exhaust options
Discussion
Agreed Rojibo - doesn't sound that different to me and just seems to be a tweaked version of the standard exhaust and similar to the Supersprint offering:
https://www.supersprint.com/ww-en/porsche-cayman-g...
There certainly doesn't seem to be a clear winner on the market, each offering has pros and cons.
https://www.supersprint.com/ww-en/porsche-cayman-g...
There certainly doesn't seem to be a clear winner on the market, each offering has pros and cons.
Twinfan said:
Agreed Rojibo - doesn't sound that different to me and just seems to be a tweaked version of the standard exhaust and similar to the Supersprint offering:
https://www.supersprint.com/ww-en/porsche-cayman-g...
There certainly doesn't seem to be a clear winner on the market, each offering has pros and cons.
Well, define clear winner https://www.supersprint.com/ww-en/porsche-cayman-g...
There certainly doesn't seem to be a clear winner on the market, each offering has pros and cons.
It does a good job, slightly louder sounding but not silly loud. Anyway, all subjective..
A clear winner for me would be something with large power gains, superb weight saving, a sound more fitting of a GT-car with minimal harsh frequencies and drone all coming in at a price that was value for money.
It's all subjective and I think there's an element of compromise with all of them, so you choose the one that best fits your own personal wants and needs
It's all subjective and I think there's an element of compromise with all of them, so you choose the one that best fits your own personal wants and needs
Twinfan said:
A clear winner for me would be something with large power gains, superb weight saving, a sound more fitting of a GT-car with minimal harsh frequencies and drone all coming in at a price that was value for money.
It's all subjective and I think there's an element of compromise with all of them, so you choose the one that best fits your own personal wants and needs
So, improved sound, power gains, low weight and relatively well priced. This may be a pick any three scenario It's all subjective and I think there's an element of compromise with all of them, so you choose the one that best fits your own personal wants and needs
I’m still undecided on mine, I need to do the valve mod, but I’m lazy and it’s cold outside. I just don’t think the exhaust comes across well over video/audio, so it’s quite hard to pick. Also, I would hate to spend £3k plus on an exhaust then find myself getting black flagged for noise!
Need to check Rennlist and see if JCR have revealed the secret of their OPF delete not requiring an ECU flash. Out of curiosity, not something I intend on doing, despite my disdain for those regs..
Rojibo said:
So, improved sound, power gains, low weight and relatively well priced. This may be a pick any three scenario
I’m still undecided on mine, I need to do the valve mod, but I’m lazy and it’s cold outside. I just don’t think the exhaust comes across well over video/audio, so it’s quite hard to pick. Also, I would hate to spend £3k plus on an exhaust then find myself getting black flagged for noise!
Need to check Rennlist and see if JCR have revealed the secret of their OPF delete not requiring an ECU flash. Out of curiosity, not something I intend on doing, despite my disdain for those regs..
Think its does need a remap as I contacted JZM and they quoted me for it..I’m still undecided on mine, I need to do the valve mod, but I’m lazy and it’s cold outside. I just don’t think the exhaust comes across well over video/audio, so it’s quite hard to pick. Also, I would hate to spend £3k plus on an exhaust then find myself getting black flagged for noise!
Need to check Rennlist and see if JCR have revealed the secret of their OPF delete not requiring an ECU flash. Out of curiosity, not something I intend on doing, despite my disdain for those regs..
Twinfan said:
Agreed Rojibo - doesn't sound that different to me and just seems to be a tweaked version of the standard exhaust and similar to the Supersprint offering:
https://www.supersprint.com/ww-en/porsche-cayman-g...
There certainly doesn't seem to be a clear winner on the market, each offering has pros and cons.
The version they fitted on the car in the video is not like the supersprint...https://www.supersprint.com/ww-en/porsche-cayman-g...
There certainly doesn't seem to be a clear winner on the market, each offering has pros and cons.
From the website it seems like the one pictured here and the 'center-muffler' one were in the final run off test at Castle Combe, and the 'centre-muffler' one is what they have at the bottom of the webpage - so a little confusing as to which is the actually offering.
IMO, based on the design, the 'non-centre-muffler' would be better to be due to the Holtz resonance tubes if they are tuned correctly - but thats just my guess.
Based on what they have said on the website they tested 4 different configurations including one that looks like the supersprint version(Center-Muffler), and another which seems to be totally unique, and would have effectively delivered something like a 'exhaust blown diffuser' - with additional centre exits. LOL.
As has been said - there are plenty of options available now for different tastes and budgets, which can only be a good thing. Choice is your friend.
At least 3 vendors say they have mechanical solutions for OPF delete Over Axles Pipes and CEL that do not require software.
Apart from what Manny has said... I've not heard anyone else actually refute the claim or prove otherwise. I guess more will come to light in time.
Edited by TDT on Wednesday 16th December 01:03
Rojibo said:
So, improved sound, power gains, low weight and relatively well priced. This may be a pick any three scenario
Exactly the point I was making 
TDT said:
The version they fitted on the car in the video is not like the supersprint...
Well their product page shows the centre muffler version so I assume it's the one for sale: https://www.litchfieldmotors.com/porsche/718-gt4-g...
So I'm no exhaust expert, but on a few of these I don't see where the gases from each bank of cylinders will mix when the valves are open. Surely they will just take the path of least resistance and go straight out the tailpipe, whereas for some reason I thought it was important that they mixed somewhere?
Rojibo said:
So I'm no exhaust expert, but on a few of these I don't see where the gases from each bank of cylinders will mix when the valves are open. Surely they will just take the path of least resistance and go straight out the tailpipe, whereas for some reason I thought it was important that they mixed somewhere?
On the Litchfield one for example, there's a valve on the lower short straight through pipe that closes and it blocks that route. It opens at ~5k revs if the exhaust button is not pressed or ~4k revs if it is.Below those revs, the gases can only route through the upper pipe which enters the large silencer which mixes gases from both banks. Above those limits the gases can exit both ways although one assumes they mostly go through the unsilenced exit. So they don't mix entirely all the time but there are elements of mixing at all revs.
I think the difference with the standard exhaust for the Litchfield solution is the mixing of banks (standard doesn't mix I don't think) and reduced silencing.
Twinfan said:
On the Litchfield one for example, there's a valve on the lower short straight through pipe that closes and it blocks that route. It opens at ~5k revs if the exhaust button is not pressed or ~4k revs if it is.
Below those revs, the gases can only route through the upper pipe which enters the large silencer which mixes gases from both banks. Above those limits the gases can exit both ways although one assumes they mostly go through the unsilenced exit. So they don't mix entirely all the time but there are elements of mixing at all revs.
I think the difference with the standard exhaust for the Litchfield solution is the mixing of banks (standard doesn't mix I don't think) and reduced silencing.
Ah I see a bit better now thanks, the reduced silencing will have a greater effect given the restrictive way the valves behave, I do think the standard exhaust mixes but they all just end up inside that huge silencer. Not fancy unplugging the vacuum lines to your valves and seeing what the difference is like on your 9m exhaust? Below those revs, the gases can only route through the upper pipe which enters the large silencer which mixes gases from both banks. Above those limits the gases can exit both ways although one assumes they mostly go through the unsilenced exit. So they don't mix entirely all the time but there are elements of mixing at all revs.
I think the difference with the standard exhaust for the Litchfield solution is the mixing of banks (standard doesn't mix I don't think) and reduced silencing.
MannyLon said:
So with regards to sound, it's the OPFs and valves that are most restrictive, right?
From experience it's the OPFs that have muffled the sound, killed the pops and bangs you'd usually get on the overrun, from driving two 718's back to back one with an OPF and one without, funny thing is they were still there, just sounded like they were trapped behind the OPFs. MannyLon said:
So with regards to sound, it's the OPFs and valves that are most restrictive, right?
It's a combination of everything - cats, OPFs and the silencer. All three are restrictive. Even with the valves open some of the exhaust gases still go through the silenced section, the unsilenced part can't handle all the gas flow by itself.Rojibo said:
From experience it's the OPFs that have muffled the sound, killed the pops and bangs you'd usually get on the overrun, from driving two 718's back to back one with an OPF and one without, funny thing is they were still there, just sounded like they were trapped behind the OPFs.
I think the engine mapping wil have affected that too. Meeting the lower particulate restrictions means not pumping petrol into the exhaust...Rojibo said:
Ah I see a bit better now thanks, the reduced silencing will have a greater effect given the restrictive way the valves behave, I do think the standard exhaust mixes but they all just end up inside that huge silencer. Not fancy unplugging the vacuum lines to your valves and seeing what the difference is like on your 9m exhaust?
Nope, I'm not bothered about increasing sound below 4k revs. If anything, I'd make it a bit quieter than it is now for pottering about.Twinfan said:
I think the engine mapping wil have affected that too. Meeting the lower particulate restrictions means not pumping petrol into the exhaust...
I agree with you, but the 718C courtesy car I had a while back, when I still had my 718C behaved in the exact same way in terms of provoking the noises out of the exhaust, it's just that they were rather muffled. They couldn't be so lazy as to just stick some GPF's on it and not change anything... could they? MannyLon said:
So really OPF is the enemy
I've reached out to JCR and asked about their kit, albeit expensive that has headers and opf delete and passes MOT.
Not just the OPF IMHO.I've reached out to JCR and asked about their kit, albeit expensive that has headers and opf delete and passes MOT.
I'd be interested to know if JCR have tried to get their car to pass an MOT and how it got on. I'd also like to know what their insurers said about it...
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