MPG performance, all P6's and P6B's
- Thread starter ghce
- Start date
Hello Graeme,
My 1974 P6B runs a circa 2002 top hat linered fully cross bolted 4.6 litre Rover V8 fitted with a custom ground high torque camshaft. Heads are 10 bolt, timing set J & P Performance double row true roller set advanced by 2 degrees. Lumenition Ignition running in a brand new (in 2007) Lucas 35D8 distributor regraphed to suit the engine. Timing is 12 degrees @ 600rpm, 28 degrees @ 3000 rpm. Fuelled by twin SU HIF6 carburettors with custom polished BBW needles, K & N air filters sitting in an airbox with 3" inlet. Estimated gross power from rear wheel dyno run 220 HP (160kW), Max Torque 300lbs/ft (400Nm). City running typically 18 to 19mpg, country running 25 to 29mpg at 60 to 75mph.
An interesting point,...with my original 3.5 litre engine, the carburettors were adjusted on the lean side and the needles were BBG. When starting even during warm weather, the choke needed to be out for a good few minutes else it would stall. With my 4.6, the tuning is if anything more to the rich side, the choke is only used for starting and thence immediately pushed fully home. The engine will idle perfectly smoothly and the car can then be driven just like a modern fuel injected car, no hesitation at all. On top of this, the engine delivers better fuel economy than the 3.5 litre engine it replaced, some 2 to 6mpg typically.
Ron.
My 1974 P6B runs a circa 2002 top hat linered fully cross bolted 4.6 litre Rover V8 fitted with a custom ground high torque camshaft. Heads are 10 bolt, timing set J & P Performance double row true roller set advanced by 2 degrees. Lumenition Ignition running in a brand new (in 2007) Lucas 35D8 distributor regraphed to suit the engine. Timing is 12 degrees @ 600rpm, 28 degrees @ 3000 rpm. Fuelled by twin SU HIF6 carburettors with custom polished BBW needles, K & N air filters sitting in an airbox with 3" inlet. Estimated gross power from rear wheel dyno run 220 HP (160kW), Max Torque 300lbs/ft (400Nm). City running typically 18 to 19mpg, country running 25 to 29mpg at 60 to 75mph.
An interesting point,...with my original 3.5 litre engine, the carburettors were adjusted on the lean side and the needles were BBG. When starting even during warm weather, the choke needed to be out for a good few minutes else it would stall. With my 4.6, the tuning is if anything more to the rich side, the choke is only used for starting and thence immediately pushed fully home. The engine will idle perfectly smoothly and the car can then be driven just like a modern fuel injected car, no hesitation at all. On top of this, the engine delivers better fuel economy than the 3.5 litre engine it replaced, some 2 to 6mpg typically.
Ron.
Pilkie
Active Member
CRIKEY!! :shock:
Slightly modernised then!!
Seems a lot of expense and effort for little overall gain to me!
Ive got a normal P6B engine in mine,granted the previous owner fitted SD1 heads,but that isnt a big change!!
Its my daily driver and it does circa 25mpg on a run,if I really take it easy and stick at 55mph,"VERY HARD TO DO :wink: ", I can squeeze a little more out of it,and I get 15-20mpg if I am very lucky around town,work and back,as it doesnt really have a chance to get fully warmed up! :|
As I dont pay car tax and insurance is cheap I can live with it! :wink:
If I was concerned at the running cost I would buy a mini!
Slightly modernised then!!
Seems a lot of expense and effort for little overall gain to me!
Ive got a normal P6B engine in mine,granted the previous owner fitted SD1 heads,but that isnt a big change!!
Its my daily driver and it does circa 25mpg on a run,if I really take it easy and stick at 55mph,"VERY HARD TO DO :wink: ", I can squeeze a little more out of it,and I get 15-20mpg if I am very lucky around town,work and back,as it doesnt really have a chance to get fully warmed up! :|
As I dont pay car tax and insurance is cheap I can live with it! :wink:
If I was concerned at the running cost I would buy a mini!
Shazzbat
New Member
Not enough time to check the performance. As I still wear the British numberplates is illegal for me to drive the car out in the road. I drive it anyway, but only throughout the city, not open roads.
According with my drive between Northampton and Plymouth when I went to take the ferry down to Spain, I think I did near 30 mpg on my 1974 2200 SC at the normal average speed of 70 mph. Even I pushed her near 85 mph twice (no police on sight!) with no complaints. The problem is that I am used to diesel cars (my everyday car is a Nissan Pathfinder) and when I hear the engine revved up I get very scared!
I am looking forward to take the car out without worries. I hope to enjoy the new Spanish plates by the end of January / early February.
Regards
According with my drive between Northampton and Plymouth when I went to take the ferry down to Spain, I think I did near 30 mpg on my 1974 2200 SC at the normal average speed of 70 mph. Even I pushed her near 85 mph twice (no police on sight!) with no complaints. The problem is that I am used to diesel cars (my everyday car is a Nissan Pathfinder) and when I hear the engine revved up I get very scared!
I am looking forward to take the car out without worries. I hope to enjoy the new Spanish plates by the end of January / early February.
Regards
pilkie wrote,..
Hello pilkie,
That is true, but I made a decision based on the options. My original 3.5 litre engine had seen 203,000 miles of use and needed a complete rebuild, so I was up for a lot of money regardless. As it turned out, the 4.6 litre has transformed my Rover into a vastly better car. I have never enjoyed driving it as much as I do now....
The fact that it delivers better fuel economy is just a bonus.
Ron.
Hello pilkie,
That is true, but I made a decision based on the options. My original 3.5 litre engine had seen 203,000 miles of use and needed a complete rebuild, so I was up for a lot of money regardless. As it turned out, the 4.6 litre has transformed my Rover into a vastly better car. I have never enjoyed driving it as much as I do now....
The fact that it delivers better fuel economy is just a bonus.Ron.
NickDunning
Active Member
Shazzbat said:
Like yourself I seem also to get better MPG from my 2200 than Rover ever claimed. My auto did 31mpg on the run up, and back from Shropshire for the RP6C National last year, and an excellent 29mpg overall on long tour up to Scotland for the SAAR in 2008. The auto certainly wouldn't do long spells at 85mph though, that is certain.
I have been away over the past week visiting my brother, and I am very pleased to say that my Rover ran brilliantly... All in all 732 miles (1179km) was covered, and on the return run over a distance of 111 miles (179km) running at 60 to 70mph for the majority of the way, 30.3 mpg (9.3l/100km) was achieved. Needless to say I am very pleased indeed. It was quite a hot day too with ambient temperature in the 35 to 36 degree C range while the in car temperature reached a peak of 49.3 degrees C. People often say to me,...Ron,...why does your car feel like an oven?
Ron.
All in all 732 miles (1179km) was covered, and on the return run over a distance of 111 miles (179km) running at 60 to 70mph for the majority of the way, 30.3 mpg (9.3l/100km) was achieved. Needless to say I am very pleased indeed. It was quite a hot day too with ambient temperature in the 35 to 36 degree C range while the in car temperature reached a peak of 49.3 degrees C. People often say to me,...Ron,...why does your car feel like an oven?Ron.
Tor
Well-Known Member
With Lumenition ignition and a 5-speed 'box, being otherwise stock and high mileage (and non-PAS), my last V8 would return 21mpg (13ish lit/100km) urban, 33mpg (85l/100km) at 55-65 mph. SU settings were fairly lean. The latter figure is exactly the same as with a Volvo 240 2.1l I once owned. Waiting to MOT my current, stock 3500S, so no stats there beyond 28mpg on the transport journey with two mountain ranges crossed.
I'm keen to know what a Weber conversion can do, esp. for urban use...
I'm keen to know what a Weber conversion can do, esp. for urban use...
tolson2000sc
New Member
I get about 31mpg out of my standard 2000sc on a decent run but it spends most of the time pottering around town not doing many miles at a time and frankly i dont want to know what mpg im getting there ignorance is bliss.
ghce
Well-Known Member
Tor said:
Am ordering a pertronix ignitorII and matching II coil in the next few days to fit to my Weber 500 enabled P6B to hopefully elliminate a pesky restart problem (still blaming the Weber at this point). So all things going well I will be able to do some MPG figures with this configuration.
Provided the pertronix unit cures my restart problems I will remove the factory fan blades and install an electric fan which will also provide some interesting MPG (or even litres/100KMs) figures for efficiency comparisons, bearing in mind my motor has 225,000 KMs on the clock and is as far as I am aware other than a cam and rocker change back in 1989 still an untouched engine.
Graeme