Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Does a bafflectomy increase fuel consumption?

I just filled up the first time after taking out the front exhaust baffle and fitting a stealth air cleaner.
Prior to baffle removal the last fill up was 147 miles with 21.5 litres giving 31 mpg.
Filled up this morning at 170 miles with 39 litres giving 19.8 mpg.

Seems a bit of a massive change!
Engine seems to run fine, possibly pops more on overrun than before, but I can't be certain.
Is that a typical figure, or should I start looking at other stuff? Lambda sensors maybe?

Any freer flowing exhaust, including a bafflectomy, should slightly decrease fuel consumption.

It's likely you underfilled the tank last time leading to your 19.8 figure. It's worth noting the tank capacity is 40 litres so you were virtually empty.

When I saw it filled up to 39, I did count my self lucky that I didn't wait a few more miles!
I'm beginning to think that I might have accidently reset the odometer at some stage as the millage of the trips I can recollect comes to more than the odo figure.
Ooops!

Popping on over run indicates a weak idle mixture, if not addressed can cause valve damage on some engine types.

The "normal" fuel consumption of an unmodified M3W is mid 30's mpg (UK gallons). It often improves with some better breathing. I would check your 19.8 mpg figure as that seems very low. If you are changing something on your engine it is a good idea to reset the adaptive maps with Protune 2, the adaptive maps will adapt to your new set up then over a few miles. A baffelectomy should be within the range of a locked standard ECU.

Thanks.
I've downloaded Protune2, read some forum posts and now look forward to loosing 2 small fiddly screws

When I carried out my two baffle bafflectomy with stealth air filter I saw better overall performance with a slight improvement on fuel consumption. Of course measuring fuel consumption is a somewhat inaccurate activity unless you drive the exact same roads in the exact same conditions with the exact same right foot throttle performance In other words with one baffle removed each side you might not see any appreciable benefit in fuel consumption.

I took the cover plate with those two fiddly little screws and carefully made a copy of the plate out of Alu. The drilled a hole in the location of the usb receptacle just barely large enough to slip the usb jack through it. Then I plugged in the cable and gently screwed down the new plate with the cable sticking out and once in place J&B Welded it in place. Once dry I took it off and checked for gaps (i was careful to not push it through to the ECU) so once sealed and dry i put it in place and torques the wee little screws down and coiled up the long cable up under the passenger side cockpit dash. Now i never have to mess with those damn little screws again!

I removed both front and rear baffles plus fitted the G56 air filter housing, MPG went from roughly 30 to 35mpg.
Since then I have had the 569 cams fitted and the eco tuned at Krazyhorse.
At a steady 60-65 on the motorway I have seen 40mpg on a long run and spirited driving on A & B roads 30-35mpg.

When new it would do 27-30.

Even on a track day at Croft I got more than 20mpg.

I once brimmed it and ran it out of fuel just to see how far it would go on a tank and got 297 miles so I now fill up between 200-250 just to be on the safe side.

what I find, on this, and the HD forums as well, is lots of talk about increased power etc etc etc etc... What I do not see is EVIDENCE for any of these claims.