Mad4slalom
CCCUK Member
Good evening just wondering what miles per gallon I should expect from my 72 hot 350?, 10 to 1 pistons, street cam , 2.02 heads and 650 double pumper ? I guess fifteen is optomistic ? .
Fuel consumption
- Thread starter Mad4slalom
- Start date
sublimemike
Well-known user
I wouldn't worry too much if I were you and you have a built motor. I have a big block and it's about how you drive it. If you poodle around gently I'm sure 15 is do able. I asked the previous owner of my ride and he said " about 4mpg if you drive it hard otherwise around 13 if you go gently and don't open the secondaries.
Roscobbc
Moderator
Back in the 'day' the hottest factory optioned 327 and 350 small blocks would have similar mpg to 'cooking' 396 or 427 big blocks. My stroker 489 dyno'd at 571 bhp - yet with a 950 cfm carb, 4 speed and 3.08 rear end (as Mike indicates) 15/16 mpg on 'A' road/motorway @ 55/60/70 mph is achievable - 12 mpg or so in urban use.
James Vette
CCCUK Member
Fuel should be free for badass rides.
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Roscobbc
Moderator
Yeah - and especially Shell V Power Super Un-Leaded........
CaptainK
CCCUK Member
My 68 small block varies between "Needs filling up again?" and "only half a tank needed". It just depends on whether I've just moving it out and back in of the garage, or actually take it for a small drive somewhere 
Either way, its all about the SMILES per gallon, and it makes me smile a lot (the only time I checked my MPG was on a long distance sensible drive using a known overfuelling carb at the time and it was about 18mpg). After that, I just don't want to know
Either way, its all about the SMILES per gallon, and it makes me smile a lot
(the only time I checked my MPG was on a long distance sensible drive using a known overfuelling carb at the time and it was about 18mpg). After that, I just don't want to know 
Daytona Vette
Well-known user
It all depends on how Sticky the Tyres are ........if they are very sticky you will not go far ........... but you will use juice
There is an algorithm for working out the exact mpg, but you need to know things that people don't know
There is an algorithm for working out the exact mpg, but you need to know things that people don't know
Daytona Vette
Well-known user
MPG is so subjective dependent on so many variables including tyre pressures and fuel octane, my previous rear mounted Holley race fuel pump was capeable of delivering 110 gallons per hour - the way to make great savings on fuel in a C3 is to go 700R4 or 5 Speed
Roscobbc
Moderator
As Barry indicates the addition of an overdrive gearbox will certainly help fuel consumption at today's typical motorway and cruising speeds. However unless the vehicle is actually running at an optimal rpm (say 1500 to 1800 rpm depending on the engines state of tune) without 'lugging' the benefits will perhaps be limited. C4's and onwards have the best opportunities for better mpg with OEM ECM controlled fuel injection and far better aerodynamics and suitable gearing. In terms of CD figures C3's and earlier car are aerodynamically much like a housebrick............
Chuffer
CCCUK regional rep
On a far more serious note than my previous quip about mpg , I think owners / potential owners of C3`s and any 40 plus year old vehicle should be far more concerned about the detrimental effect of modern petrol and the proposed increase of ethenol content to 10%.
Far more learned scholars than me have written in great length about its effects on rubber fuel lines , fuel tanks and carburetters . It makes for worrying reading for classic cars in the future . Our carbon footprint has long since cancelled itself so the planet won`t get saved on the meagre amount of ethenol in the petrol classic cars use per annum.
Far more learned scholars than me have written in great length about its effects on rubber fuel lines , fuel tanks and carburetters . It makes for worrying reading for classic cars in the future . Our carbon footprint has long since cancelled itself so the planet won`t get saved on the meagre amount of ethenol in the petrol classic cars use per annum.
Daytona Vette
Well-known user
The less Ethanol in the fuel the more MPG you can get, you will not get far on a gallon of Ethanol
Always use Esso if you can to help your Mouse or Rat to get a Tiger in your Tank
People ask
Which petrol does not contain ethanol?
There is currently no requirement for renewable fuel (such as ethanol) to be present in super unleaded (97 grade petrol). Esso super unleaded petrol (Synergy Supreme+ Unleaded 97) is ethanol free (except in Devon, Cornwall, the Teesside area and Scotland).
Always use Esso if you can to help your Mouse or Rat to get a Tiger in your Tank
People ask
Which petrol does not contain ethanol?
There is currently no requirement for renewable fuel (such as ethanol) to be present in super unleaded (97 grade petrol). Esso super unleaded petrol (Synergy Supreme+ Unleaded 97) is ethanol free (except in Devon, Cornwall, the Teesside area and Scotland).
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Roscobbc
Moderator
Shell VPower Nitro Super Unleaded according to Shell's website 'may' have a 5% Ethanol content. It is up to the gas station retailer whether the filling station carries VPower with Ethanol. I can imagine going to one of the local Shell filling stations and asking "does your VPower Super Unleaded have a 5% Ethanol content" even if the person at the till understands your question they just won't have a clue. Even if they answer "no it hasn't" would you believe them? - how would you be able to tell?
I'm hoping that our new advertiser and supporter Anders (from Anglo American Oil Company) who sell racing fuels will be able to tell us the percentage 'mix' required to add his Sunoco 110 Ron super unleaded to 4 star pump gas to perhaps bring octane rating up 100 or 102 octane.
I've seen the effect that petrol with Ethanol has on new rubber fuel piping - it rots out internally and becomes porous. However I'm sure that rubber piping that is Ethanol resistant is available - problem being that you'll probably be sold the cheap crap that rots.
Chuffer
CCCUK regional rep
I am aware of the Esso spec petrol situation and cannot for the life of me understand why zero ethanol content is only available in certain parts of the UK !!
That`s purely accademic anyway because there are no Esso stations for miles around where I live . It is a Shell / BP monopoly around here at rip off prices except for cheap supermarket crap !
That`s purely accademic anyway because there are no Esso stations for miles around where I live . It is a Shell / BP monopoly around here at rip off prices except for cheap supermarket crap !
sublimemike
Well-known user
On my other car I have used tesco 99 octane until recently, now using Esso Supreme 97. I suspect ethanol having a part rotting ;
Accelerator pump diapragms
Fuel pump regulator diapragm - nearly a fire with fuel spraying in the engine bay
Rubber fuel hose saggy and blown.
Enough is enough - no more ethanol - worth paying a bit more for Esso.
No ethanol in Av gas.
Accelerator pump diapragms
Fuel pump regulator diapragm - nearly a fire with fuel spraying in the engine bay
Rubber fuel hose saggy and blown.
Enough is enough - no more ethanol - worth paying a bit more for Esso.
No ethanol in Av gas.
Roscobbc
Moderator
Thing is - items like accelerator and fuel pump diaphragms and hoses will have a limited life irrespective of whether one uses an Ethanol based fuel (or not) and would reasonable have been replaced several times during the life of a 40 or 50 + year old car. I'm sure branded carb parts from Holley etc will have been long upgraded to allow for even a future 10% Ethanol mix. Of more worry would be sub-standard hosing from third world suppliers. Seen it myself on my own car with a stainless steel braided hose inter-connecting the fuel feeds between float inlets on a double pumper Holley - within a year of installation the rubber core became porous - degrading rubber was 'hidden' by stainless steel braiding - really lucky I didn't have a major fire.
I'd also be concerned to about this.........Ethanol (like Methanol) is hygroscopic (i.e it absorbs moisture). So if laying-up a car over winter in a potentially damp or humid environment there is a real risk of water in your fuel. Perhaps with a 5% content (soon to be 10%) not as big a risk as if the car was running on 100% Methanol where race car fuel tanks are drained-off after a meeting and the oil is changed.
But we should be concerned with our choice of filling station. The risk of water contamination in the storage tanks at your local service station will potentially become higher - and perhaps even higher for SuperUnleaded where the pumps will see less use than regular 4 Star. Just saying.......
I'd also be concerned to about this.........Ethanol (like Methanol) is hygroscopic (i.e it absorbs moisture). So if laying-up a car over winter in a potentially damp or humid environment there is a real risk of water in your fuel. Perhaps with a 5% content (soon to be 10%) not as big a risk as if the car was running on 100% Methanol where race car fuel tanks are drained-off after a meeting and the oil is changed.
But we should be concerned with our choice of filling station. The risk of water contamination in the storage tanks at your local service station will potentially become higher - and perhaps even higher for SuperUnleaded where the pumps will see less use than regular 4 Star. Just saying.......