718 Gt4 exhaust options

[MannyLon]

Twinfan said:

Dyno run of the JCR system now posted on YouTube:

https://www.youtube.com/watch?v=SQPAxLr4MvY

UK car, all stock except for the rear silencer replacement so the cats and GPFs are present:

OEM - 356.18WHP/275.87WTQ (409.61HP/317.25TQ)
JCR - 369.48WHP/287.06WTQ (424.90HP/330.12TQ)
GAINS vs OEM- +13.30WHP & +11.19WTQ (15.29HP/12.87TQ)

15HP from a silencer swap which is impressive Hopefully similar silencers would give similar gains if the stock silencer is so restrictive.

That is very impressive. Never seen a standard “back box” swap make that much power..

[Twinfan]

MannyLon said:

That is very impressive. Never seen a standard “back box” swap make that much power..

Nope, me neither. It shows how restrictive it is due to what I assume to be the 68dB noise limit, given that Andreas Preuninger stated that the new 4.0 meets all current and future known legislation.

[MannyLon]

Twinfan said:

Nope, me neither. It shows how restrictive it is due to what I assume to be the 68dB noise limit, given that Andreas Preuninger stated that the new 4.0 meets all current and future known legislation.

Well, jcr have proved their exhaust increases power. Was gonna go supersprint but not sure now.

Jcr offer a non silenced version which is apparently 3db louder.

[gtsralph]

One wonders how much would be gained with a more efficient or no GPF. I always understood the GPF was the main new restrictive element.

[SWGT3]

MannyLon said:

Well, jcr have proved their exhaust increases power. Was gonna go supersprint but not sure now.

Jcr offer a non silenced version which is apparently 3db louder.

I have the non silenced version. Will try and get some videos of it this weekend.

[Twinfan]

gtsralph said:

One wonders how much would be gained with a more efficient or no GPF. I always understood the GPF was the main new restrictive element.

Quite a bit I suspect. JCR are working on that too.

[MannyLon]

SWGT3 said:

I have the non silenced version. Will try and get some videos of it this weekend.

Thanks Jon. Hope you’re well. Loving the spider..

[MannyLon]

Twinfan said:

Quite a bit I suspect. JCR are working on that too.

Would it pass MOT?

[Twinfan]

MannyLon said:

Would it pass MOT?

No, it would fail on emissions and I doubt you'd get insurance for road use if you declared it.

[gtsralph]

Twinfan said:

Quite a bit I suspect. JCR are working on that too.

Cargraphics have that now (with / without TUV versions) and a full system with equal length 200 cell cat manifolds.

[Twinfan]

Fabspeed have something similar too I believe.

[TDT]

Not sure if previously mentioned, BC Fabrications have a couple of offerings.. UK based, High quality.
www.bcfabs.com

[RSVP911]

SWGT3 said:

I have the non silenced version. Will try and get some videos of it this weekend.

Thoughts ?

[gtsralph]

For comparison, Static noise test at Castle Combe and Goodwood at 5k revs (ECU limited) for stock exhaust has not been more than 96db.

[woollyjoe]

So Paris is introducing the equivalent of speed cameras for noise and other cities been investigating same including London. So if your car (or in case of Paris, your scooter) is too loud, you get ticketed.

It’s tech that’s been around for while but with new regulations and Covid, wonder when them start on UK roads.

[MannyLon]

woollyjoe said:

So Paris is introducing the equivalent of speed cameras for noise and other cities been investigating same including London. So if your car (or in case of Paris, your scooter) is too loud, you get ticketed.

It’s tech that’s been around for while but with new regulations and Covid, wonder when them start on UK roads.

Oh, please no. Seems a bit unfair on cars that were produced loud from the factory or are old.

[Bedlamater]

More details on the Akrapovic. No doubt the quality will be the very best but the power gains seem low compared to JCR. Hmmm

https://tagmotorsports.com/akrapovic-slip-on-race-...

[Twinfan]

Given that they do the same job, and it's only a silencer, I would think the Akrapovic stats are more realistic. The JCR figures are very strong, maybe too strong?

[MannyLon]

Twinfan said:

Given that they do the same job, and it's only a silencer, I would think the Akrapovic stats are more realistic. The JCR figures are very strong, maybe too strong?

Would be good to do independent testing of the exhausts.

[Taffy66]

The Akrapovic is strictly for track use only and not legal for public road use.