Engine efficiency, now and then

[SeijaKessen]

Funny sportscar season that 1973, while the 12-cylinders where nowhere in F1, they ruled sportscars with Ferrari and Matra, while that Ford-sponsored Weslake V12 was a dog in John Wyer's Gulf Mirages.

Back on topic, where do we begin, how much fuel did a Cosworth kit-car carry at the time, 240 liters comes to mind?

I don't have any books on me right now --given that Chapman was notorious for trying to run his cars with less fuel than the mechanics wanted-- so whatever the capacity was for the Lotus 49, there was a good chance it was never filled to capacity unless the mechanics could sneak one past Colin.

[strad]

I can't find the efficency numbers but this PDF has a ton of info that I have never sorted completely thru.
http://grandprixengines.co.uk/cosworthstory.pdf

[SeijaKessen]

Thank you for posting that PDF...holy crap it is great. =D>

[strad]

Had it for a while along with other stuff, but much of it is beyond me so I've never read it all, but it does have some stuff...For some reason I thought you could extrapolate effiecency from the figures we have.

[SeijaKessen]

What else do you have like that PDF?

It looks like the Lotus 49 was running two 15 gallon tanks, plus a 10 gallon tank, which translates to about 151 litres.

151 seemed too little at first, but the Ferrari 312 F1-67 had a 160 litre capacity, so 151 sounds correct given Chapman's obsession with saving weight. Plus it wouldn't have needed the extra fuel the Ferrari V12 would have needed.

[SeijaKessen]

xpensive-

I apologize if this video is too far off-topic, but I just wanted to post it so people could see the first time the Cosworth DFV was run at Zandvoort in 1967. The footage is fantastic.

[youtube]http://www.youtube.com/watch?v=V6cm3eWEHM0[/youtube]

[strad]

You know, I'm having a heck of a time finding the fuel capacity.
However I did find this about the Weslake which may have been what you were talking about earlier...I wonder if they burned their valves because the mixture got contaminated with excess oil.

If anything, the least favorite aspect of the engine was the oil scavenging system which meant that it was less efficient than it should have been and therefore at the beginning of a race it would have really good power for one to three laps then would lose a portion as the engine sort of 'drowned' in its own oil. It did not stop the engine, but often took the edge off it.

[xpensive]

Ok...

It looks like the Lotus 49 was running two 15 gallon tanks, plus a 10 gallon tank, which translates to about 151 litres.

151 seemed too little at first, but the Ferrari 312 F1-67 had a 160 litre capacity, so 151 sounds correct given Chapman's obsession with saving weight. Plus it wouldn't have needed the extra fuel the Ferrari V12 would have needed.

That sounds far more reasonable, while I have a vague memory that the new rules for 1973 stipulated three separate rubber-bellow tanks, each holding 80 litres, but that doesn't mean they were all filled of course.

[Tommy Cookers]

Thank you for posting that PDF...holy crap it is great. =D>

Agreed !!

that website truly is a GOLDMINE (if you mine it)

it contains answers to my historical question
it agrees with my view on the false god of piston speed limits (and how we got to that)
engages strongly with another hobbyhorse of mine, (writers missing) oversized valves in the recent and distant past
shows that often design moved through fashions

shows us that the 1967 Lotus 49 had insufficient tankage for Monza
but no actual BSFC figures


try it ...... grandprixengines.co.uk

[Tommy Cookers]

Harry Weslake was an old fart already back then, he couldn't get much right, not even the 1973 iteration with Ford-money was good enough for sportscars as I can recall?

in the late 50s Weslake (also a farmer in Rye) was developing the Austin Westminster for saloon/touring car racing
a friends father was also a farmer in Rye and owned an Austin Westminster, Harry W offered to convert it to race spec at cost (the offer was declined)
when Dan Gurney won the 67 race of champions his Weslake engine used Castrols agricultural oil (I knew the Castrol man who chose it)

the Weslake was basically 12 cylinders of the BRM 2+ litre V8, so was almost the same stroke as the DFV anyway
(John Surtees said the BRM V12 had undersized oilways until the year after he left)

[xpensive]

From what I can understand, Carlo Chiti's Alfa Romeo flat-12s used by MrE's Brabham team in the 70's had a terrible thirst for petroleum distillate, any numbers there?

[strad]

try it ...... grandprixengines.co.uk

Great site Tommy,,,,thanks a ton....would have sworn I posted that but I dont see it...thank you again.

[SeijaKessen]

From what I can understand, Carlo Chiti's Alfa Romeo flat-12s used by MrE's Brabham team in the 70's had a terrible thirst for petroleum distillate, any numbers there?

One thing I can tell you is that all of the Brabham cars powered by the Alfa Romeo's flat 12 had a fuel capacity of 45 gallons which translates to 170 litres, or 170.344 litres to be precise.

The last year the Brabam's were powered by the Cosworth DFV V8, the fuel capacity for the cars were 41 gallons or 155 litres.

They required 4 gallons/15 litres more in fuel capacity in the switch from the DFV to the Alfa flat 12.

[riff_raff]

Here's a link to a tech paper on Honda's RA168E turbo F1 engine from the mid/late 80's.

http://www.scribd.com/doc/70831636/Hond ... 8-e-Engine

It gives engine BSFC curves and heat values for the fuel used. From that information you can calculate BTE numbers. The BTE numbers from this engine were actually quite good, but I'd speculate that modern F1 engines are probably better. Fuel/ignition systems are light years ahead of what Honda used two decades ago, as are the engineering simulation capabilities.

[Tommy Cookers]

IMO the paper shows that there is nothing unique about Toluene except its density (crucial when fuel-limited by volume)
it reminds us that n-Heptane is a specially bad fuel (it literally is the standard for poor detonation resistance)

the RON test used then for F1 fuel definition is a 600 rpm test (ie unrelated to real eg F1 engine conditions)
detonation is driven by temperature/pressure and time (temp is fixed, pressure ie compression varied in Octane tests)

at 600 rpm n-Heptane has all the time it needs to detonate, so detonation occurs at low CR (this gives 0 Octane)
at 600 rpm a pump fuel eg 92 Octane hasn't had enough time to detonate (at the CR above), so can use a much higher CR

turbo F1 wanted the highest CR (fixed boost) with 102 Octane (RON) fuel (of high density as fuel limit was in litres, not kg)

Toluene was outstanding for density, but tested maybe 120 RON
they chose 84% Toluene/16% Heptane as the densest possible 102 RON blend and set the CR around this
the lower Toluene/lower Heptane blends (102 RON but having less detonation resistance in F1 use) could not take this CR (except by retarding ign timing, which gives a skewed assessment)
(the MON data give similar but lower Octane numbers, MON or mean of (MON+RON) are used today)

this blending of high detonation resistance fuel (Toluene) with some very low detonation resistance fuel (Heptane) works because the Heptane has already made its contribution to detonation in the RON (or MON) test
the tables show that the Heptane content is the dominant factor, and suggest that other fuels with a RON as high as Toluene's (eg alcohols) could be blended with Heptane to similar advantage
this blending could be seen to be against the intent of the rules on fuel type via Octane limits

(RON etc use lean mixture, so ignores eg the natural gain in detonation resistance due to mixture richening, some petrol/gasoline (alkylate) fuels have this greatly enhanced, and could also be used blended with Heptane)
such fuels were surely in use before turbocharging, in a similar position relative to the fuel rules

IMO Toluene blend was first used by turbo F1 when power grew (pre-4 bar 1100 race bhp was intended) so the fuel quantity required became too bulky and heavy with existing fuel (as above?), alcohol blends would be disastrous in this regard)
presumably a lower Toluene blend would have been used in F1 (and in endurance?) after the banning of turbos if it was better than existing pre-Toluene fuel (was any Toluene used post-turbo ??)
now low alcohol blends are in favour/compulsory in F1, and (high/any?) Toluene blends banned

in BSFC terms actual pump fuel can be slightly better (in some engines) than Toluene blends, with alcohol blends inherently worse
(EU road fuel in now 5% min alcohol so has increased consumption/worse BSFC and effectively greater tax)