Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Exhaust / Air Cleaner upgrades - conclusions

Be careful with terminology here, as there are quite a few 'sports' exhaust options around the place right now.

Originally, there was a Sports Exhaust system available for special order from the MMC and this was EXACTLY the same size and shape as the OEM stock exhaust, but with absolutely nothing inside it - straight-through, no baffles - so it made power over the stock item, but was VERY VERY LOUD in doing so. For interest, the Part Numbers in chrome finish are U310021 / U310022 and are about £200 each. Some like them, but most think they're too loud I suspect.

Then came the MMC Stage 1 exhaust which is a new item and it is the base for the MMC Stage tuning options. It is still a small profile system but this time has a 'technical' turbulence-inducing baffle in it to reduce the noise without using too much power. A popular design in the US for Harleys I believe. As has been reported though, this is still quite noisy, but it retains a nice 'low profile' that keeps the original look. Not seen one in the flesh but there are a few members on here with them. Stage 1 needs the airfilter mods too, as induction is a little restricted as stock too.

Then there's the Garage-56 kit, about which much has already been written. This is my preferred option as it makes power without noise (in fact only 97dB measured on Monday this week at Goodwood), but the silencer has to be larger to deliver the goods. In my case, with black heat-shields, I think it maintains the original look and the mild increase in size would not be obvious unless parked next to a car on stock pipes. Not a single person at Goodwood noticed on Monday, apart from Mark Reeves, which is kinda understandable! These (with subtly bigger air-cleaner cover) restores power to that advertised at the start, if not a little more perhaps.

Only the MMC Stage 2 and 3 kits include ECU updates, as only they have the key to unlock it. This will undoubtedly add some fine tuning to the setup, but from the tests and measurements that the G56 guys did it appears that the stock ECU mapping was probably done on a well-breathing engine (ie: before they were progressively strangled, for whatever reasons) and therefore continue to work better on a well-breathing G56 setup as well. Remember the pinking and detonation we all suffered in the early days? All down to the inability for the hot exhaust gases to exit the combustion chamber and immediate header area. Massive build up of heat (hence glowing headers, even at idle....) causing pre-ignition. Take away the restriction and we are pink-free forever!