your mileage may vary....

my 456mgt runs perfectly. i have recently had it inspected 2 months, and have done a fault free 3000 miles since. but my gas mileage is awful...so i just wanted to check with the rest of you as to what you might be experiencing.

on the highway in france where you cant really push it at all, going at an avg of around 90mph, i got 15.04 mpg.
on the highway in italy, where you can really push it, going at an avg of at least 100mph (with bursts up to 150mph), i got 12.83 mpg
but here is the kicker, around town here on my daily 2 mile commute to work and back, i am getting 6.4 mpg !!!

do i have a fuel leak??? it smells a bit of fuel in the mornings, but there is nothing visible in the engine compartment or on the garage floor.

 

My 456m gta gives me 14 or there abouts mixed driving,with not too much urban mileage.

 

you mention one of two things I never have noticed in my five years of owning a Ferrari: Gas mileage and gas costs....

have never looked

BUT, having said that, I noticed in the 456, that when the gas-needle gets below the 1/4 I had better start looking for a gas pump, which is why I always keep it above the 1/4 mark. can you imaging stranded in a beautiful car because ya' ran out of fuel? not fun.

 

...from mine.

Just checked the highway mpg from my recent trip to Montreal. I was so (pleasantly) surprised to see it...

Konstantinos

 

My 550 is about the same i think.

It's mainly to do with poor ECU that is so out of date for what caliber of cars we have. They are pretty much batch injection, so not necessary fuel is put int at the same time.

if you wanna fix that, you gotta get the Motec M800 or similar that does seq. Injection so only injects 1 at a time.

This resulted in that Saurus's V12 TT car about double the gas mileage, well that's not too bad, I can deal with that.

I have been contemplating to get that done, but mmmm. for nearly 10k dollar job, is it worth it ? hard to justify....

 

is this a new engine management chip you are talking about? surely they can be obtained for less than $10k !

 

I get 8.5 mpg in my 2003 575. Hopefully I can it into the 7's soon. At this point it would mean I am having a bunch of fun with the car.

 

I am surprised to see that your average in France was 90mph, since the local speed limit on highways is 81 mph.
I just made a trip from Holland to the Riviera and back in my 456 MGT, and including stops for fuelling and coffee drinks and the unavoidable traffic jams, my average was 65mph.
I consumed between 17 and 18 mpg depending on how flat the countryside was.
I did not (dare to) measure how much the consumption was with town driving and shopping, but it must be something like 8 to 10 mpg.

 

Sequential injection is a little bit better than "all at the same time", but a factor 2 seems very unlikely.
Take as an example a 12 cyl engine running at an average of 3000rpm, meaning 18000 combustions per minute or 300 per second.
In a sequential system, this means that every 3.3 millisecond another injection cycle is starting
In a batch system the first cylinder receives its injection just in time, but the last cylinder receives it 17 msec to early.
Now how much petrol can evaporate in 17 msec, also implying that it would than be used by other cylinders since it cannot vanish.
If it was a significant amount, it would mean that the some cylinders would receive too much petrol and the last cylinders would always be too lean, sind all receive the same amount injected to start with.
But the effect of this all is only marginal in real life.

 

the speed limit in france is 130kmh (110 if raining). but you can drive up to about 140 without getting a ticket, and you can drive up to 160 kmh and get a ticket but not get your license taken. so i was driving at 160 for as much time as possible, and being slowed by traffic etc, which lowered my average. (and for those of you thinking that you can get away with this infringement easily, forget about it, the new french cop might as well be gestapo - and in a ferrari with foreign plates you are automatically picked up just for the fun of it.)

no such concerns in italy provided you are in the right car

 

In my experience, it's not high speeds that are the mileage killers, but driving around town. Combined (30%city/70% highway), my GTA gets around 14. At a steady 75-80, it'll be around 19-20. I've never done a complete tank just driving around town, but I imagine that the sub-10 mpg you experience would be normal.

 

That's my experience as well, in the 456GT.

 

this is certaily true in my case. because i only do a very short commute, the car never gets a chance to warm up and run leaner before i shut it down. so it runs rich for 10-15 min and then the same again on the way home. this is getting me 6mpg. even my caddy srx gets more like 14mpg in the same scenario. our cross to bear i guess

 

I just read this thread for some reason ... I have put about 10,000 miles on a 456M-GTA over the past year. I have the data for the most recent 8333 miles.

US MPG 14.81 with a Max/Min of 10.21/18.5

This is with more than quite a bit of motorway driving. YMMV

(I return to your previous programming)