Not to plug a product but FuelCat apparently is not snake oil I just cannon balled' across the mountains here and got the best milage I've ever had by a wide margin. My average was 15mpg at best. The mythical 20+ mpg in a V12, my car is now within arms reach of my friend's 2017 2.3L ecoboost lincoln suv (same weight) for fuel mpg

Fuel Cat

 

I will only believe a laboratory engine test rig controlled test!

 

If fuel mpg is so important to you, you better drive a 4.0 instead of a V12. Or fill up with high-octane gasoline and bring the ignition forward.

 

Good to know.

But the 20+ MPG was never actually mythical. When I had an XJS I once managed 23mpg (USA measure) and 20mpg was quite doable on road trips. It requires careful (and boring) driving, that's all !

If I drove the way I liked to drive, 17-18mpg on the highway was the norm

Cheers
DD

 

would it not have been better to have broken 150mph, just saying

 

Because when you are coming down the mountain side you are not using any fuel lol. Just messin with ya.

 

Lol given my car's poor mpg history this new record is quite good, Always used 94+ gas but this seems to do the trick.

 

I think there's truth in that, oberved in my 1989 cross-continent road trip with a friend...we got better gas mileage during the Rockie Mountain leg than the Prairie part. Carb'd 1983 Tercel 1.5 5-speed 64 bhp that never seemed too little.

 

The air is thinner so your throttle was probably opened wider, which reduces your pumping losses and improves mileage. Do you usual get 15 through the mountains or at sea level?

 

when travelling thru the mountains i try to get the 85oct. ,seems to run better with slightly more power, so need less gas pedal!

 

15 was best case scenario at any elevation...I was down to 280km/tank in the city which is horrid...normally I was at 400km a tank city/mixed but this is a leap ahead I did not expect

 

my 1978 XJS averages around 17/18 MPG at 65/70 cruise, and it is modified with much more power when needed!

 

Where did you fit the unit... interesting what their site says.... me I am all for using less gas.
I read some drop from 98 to 91 lead free petrol..
Do tell more. Not everyone is laughing I will add!

 

Duke, this system has been tested and proved to be ineffective. The company concerned were legally barred from making claims that it did any such thing as improve power or fuel consumption. A quick 10 mins on google will show you. A v12 HE non-cat Lucas ignition engine in good shape will get 18 to 22 miles per imperial gallon however driven, and about 1716/17 in traffic. That's the best it can do, and interestingly, even modern petrol engines of the same capacity very rarely get any better real-world MPG, as many roadtests showing overall consumption testify.
Where a modern large capacity petrol engine can score MPG-wise is if you drive it at 70/80 MPH steadily, as they are all optimised for that steady state motorway cruise. But start driving the things, and it is a very different story.

 

I can routinely do 24 mpg with my 6.0, all it takes is the usual things: tires at proper pressure ( I use 35 psi), lots of cruise control use, and some anticipation in driving and drive smoothly as possibly. Also keep the speed under 110 km/h.

I used to have a Series III V12, and it would do 22 mpg, but that also had the 3 speed transmission. A faulty dump valve will really bring the mileage down, from 22 to 16-17. The V12 is very sensitive to the ignition advance working correctly.

 

Why have a V12 and worry about economy, really.

All mine use what they use, and the smile, due to performance, and sheer GRUNT, on the open road, is PRICELESS.

The PreHE, OH Dear, that fuel gauge moves quicker than the bloody Tacho when in a hurry, just as well its got 2 tanks.

My HE AVERAGED 25MPG (Aussie miles and gallons) on the 25000km road trip the Manager and I did years ago. That incorporated highway, side roads, HEAPS of dirst roads, some even only tracks. Speed limits mainly 110KPH ish, and one State NO speed limits back then, so the limits of the car and my Bravado were put to the test.

Cruise control, of course for the BORING stints, but otherwise, DRIVE the damn thing.

Around our suburbs 50KPH limits, and it returns 15ish MPG.

Life is short, a PROPERLY set up and running V12, is a RARE beast indeed, so to NOT enjoy one when yours is "ON SONG", is a waste of a car to me.

Bang Juice, there will always be enough for what we want. I will be long gone when the "Golf Buggie" brigade takes over the market.

 

i like that comment,Golf Buggie,, we call them Golf carts! HE-HE!
i own one but it never on a highway!

 

The above is true, why own a V12 if fuel is a concern? This is my daily driver and road-trip car I already pay 1.75/Liter and that is before the injector lubricants, additives, etc and well before I mix up any 100octane "road-trip" gas. Its just a personal milestone for me going from 15mpg at best to nearly 22mpg over some very trying mountain roads. I bought a 3-unit peice and plopped it into the tank, I have made the drive a million times and never got the Mpg's I did nor the slight turbo whistle from the engine except with Xyelene+94oct (DIY race gas). These V12s really do like the expensive gas haha.

 

I use it as an indicator of engine efficiency and state of tune. If I'm getting 15mpg and everyone else is getting 20 I'd want to know why, and assume the engine isn't running as well as it could.

 

If you saw my repair history you'd be as lost as me...what COULD possibly be causing it when damn near everything was redone right down to the injectors themselves!