Exhuast flap permanent open

[rjn21]

I have a UK Supra with B58. Due to EU regulations we have a monitored GPF/OPF, post cat, pre muffler. The sound of the exhaust in the UK is, frankly, absolute crap. It sounds like any bland basic car. There are very limited pops and bangs in sport, and no real exhaust noise – any noise is all generated by the sound faker through the speakers.

As the GPF is monitored by a pressure sensor, removing the GPF will trigger a fault code, possibly a CEL, possibly a limp mode.

If the cats are removed with a freeflow downpipe, that definitely will cause a CEL as the O2 sensors will not see the correct readings, possibly a limp mode, and the car will fail our inspection (MOT).

According to Milltek, the use of a 200 cell sport cat downpipe may (i) also cause a CEL/limp mode (presumably the target O2 readings are very near to a 600 cell stock cat) and (ii) lead to damage to the GPF (new one on me - I don’t know either way if that’s correct).

The ECU can be flashed to remove the CEL, obviously voiding the engine/drivetrain warranty and giving an excuse for total warranty denial.

In the meantime I have fixed the exhaust valve open permanently. Its very slightly louder, nothing exciting.
Again according to Milltek unplugging the exhaust valve may result in an error. To avoid any errors and permanently fix the valve open, use BMW part 18302411427 exhaust flap simulator.

Start the car.
Put in sport mode.
Verify exhaust flap is open (easily visible through pipe).
Stop car.
Disconnect exhaust valve actuator from wiring cable (press clip to unlock).
Connect BMW part 18302411427 to wiring cable in place of actuator.
Tuck cable behind heat shield out of the way and secure so it doesn’t rattle.
Cover actuator port (use contact grease or something to stop the contacts rusting).
Done. 10 minutes. Lift not needed but easier with one.

My next step, as I don’t want to lose warranty, is to completely remove the muffler from the exhaust. I suspect it will still be crap due to the GPF.

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[Bosstee]

I suspect you won’t get any additional pops an bangs by installing an axle back system. Sound might get a bit louder and depending on what you go with you’ll either get a deeper or higher pitch. Check out Milltek and Remus sound files on their webpage and/or YouTube. The ECE approved versions are highly disappointing.

 

[Paolo]

Interesting to read this.

Seems like the Aussies and UK have same tune which removes the burbles exhaust sounds unlike the USA/Canadian supra.

I learned this quickly with the AMG A45s which has the GPF and sounds pathetic (well cmpared to the older model).
Must be to do with new Euro CO2 emissions.

 

[MA617M]

No, us Aussies have the burble and crackle. We have the US exhaust system, not the GPF one that EU got.

Whether it's as loud in terms of volume as the US cars, I have NFI. Maybe the crackles aren't quite as loud, but when it's cold ambient temperature- they sound exactly like US ones.

Also - unless cold start - the exhaust flap is permanently open on the Au models.

 

[MA617M]

 

[Paolo]

https://www.supramkv.com/threads/me...-track-at-summit-point.1759/page-4#post-41285


https://www.supramkv.com/threads/me...-track-at-summit-point.1759/page-5#post-41312


Looking at rear photos of Aussie Supras, you guys get the 45 degrees exhaust tip like schmee which is uk.

Enjoy.

 

[MA617M]

Hmmm, good pick up. I never noticed the rear muffler being different.

I really only looked at the centre section (resonator and cat) as well as the dump pipe (slip join (US), not V band (EU)) plus no GPF

Perhaps we have the US dump and mid section, with the EU rear?

That said, in this video, the tips are angled cut, like the rest of the world?



interesting though, might have to do a P/N cross reference

 

[absaifan]

Hmmm, good pick up. I never noticed the rear muffler being different.

I really only looked at the centre section (resonator and cat) as well as the dump pipe (slip join (US), not V band (EU)) plus no GPF

Perhaps we have the US dump and mid section, with the EU rear?

That said, in this video, the tips are angled cut, like the rest of the world?



interesting though, might have to do a P/N cross reference

Well, my car has the exact same 45 degree angled tips, same downpipe / exhaust system as the US model got it from the dealer here in Dubai.

Sounds like Europe and UK have the restricted Exhausts.

 

[J_Orr]

My UK model has the rear exhaust valve constantly open.

I am looking at options of making it louder

 

[MA617M]

Would you guys mind getting a photo of the part number on the rear muffler, for cross-reference?

 

[Bosstee]

Perhaps we have the US dump and mid section, with the EU rear?

I remember @Guff saying there should be 3 versions. US(loudest,) Japan (loud,) and EU (quiet AF)

My guess is you guys got the Japanese version.

 

[geert.bieseman]

For our EU-spec cars, we can make the pops and bang louder with a modification in the ECU.
Mine is now loud as f*ck on downshifts with still the GPF and standard exhaust.

But during normal driving in sport, it is still too quiet indeed.
In normal mode as well, but I don't mind that as daily.

 

[rjn21]

Would you guys mind getting a photo of the part number on the rear muffler, for cross-reference?

This is the UK / EU one for reference:

So same part no as Australia

 

[MA617M]

Great, thank you!

Now, USA, your turn!

 

[CarGuy11]

Does the flap close at all in SPORT mode? It doesn't seem like it.

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