Biggest Car Engines

[Mactech]

ranked-largest-engine-made-every-major-car-company-0

Mercedes is close to top of the league, but surprisingly out 'cubed' by both Renault and Peugeot!
I was surprised to find fellow French manufacturer Citroen, was plumb last...there are a few surprises in the list.

 

[BTB 500]

I guess this is for production road cars only? Many of the early 'specials' had huge engines e.g. the Fiat S76 at 28 litres (1910), Blitzen Benz at 21 litres (1909), etc. Those were both just 4-cyl engines too - pistons like dustbins

 

[BTB 500]

Love this video of the Fiat in the wet at Goodwood, on what look like pram tyres

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[Bellow]

What naturally aspirated road going engine made the most power from its displacement ie, specific power output?
To get the ball rolling. consider the Aprilia RS250 motorcycle. 55hp from 250cc. 440hp/litre. Is there a road going NA engine that beats that?

 

[BTB 500]

55hp from 250cc. 440hp/litre. Is there a road going NA engine that beats that?

55 hp from 250 cc is 220 hp/litre?

 

[Bellow]

55 hp from 250 cc is 220 hp/litre?

Thing is, that engine will have an exhaust port that is half the height of the cylinder so only half the swept volume is available for power production so it is only really a 125cc engine. Unfair? OK, lets return to the convention of counting all piston motion (and thus, swept volume) utilised in one cycle - and we will have to double the capacity of any 4 stroke for the comparison to be fair.

 

[ALFAitalia]

What naturally aspirated road going engine made the most power from its displacement ie, specific power output?
To get the ball rolling. consider the Aprilia RS250 motorcycle. 55hp from 250cc. 440hp/litre. Is there a road going NA engine that beats that?

Thats a two stroke.....so cheating with double the number of power strokes!!

For fairer comparison my girlfriend at the time has a GSXR 250R Suzuki with a tiny 4 pot 16v lump......(the whole bike was tiny TBH!........it could rev to 19500 rpm and made 33.1kW(45PS) at 15000rpm! It really sang! Very hard work to ride quickly....only 112mpg flat out!!

 

[BTB 500]

From a quick Google it looks like 166 hp/litre is about it for NA road cars:

The naturally-aspirated cars with the most power per litre (List) | GRR

Thirteen NA screamers, from the Honda S2000 to the Aston Martin Valkyrie…

www.goodwood.com

T.50

www.gordonmurrayautomotive.com

 

[BTB 500]

Thing is, that engine will have an exhaust port that is half the height of the cylinder so only half the swept volume is available for power production so it is only really a 125cc engine. Unfair? OK, lets return to the convention of counting all piston motion (and thus, swept volume) utilised in one cycle - and we will have to double the capacity of any 4 stroke for the comparison to be fair.

Hmm ... a 2-stroke with a tuned pipe exhaust is arguably not naturally aspirated though?

 

[ALFAitalia]

Hmm ... a 2-stroke with a tuned pipe exhaust is arguably not naturally aspirated though?

No forced induction = naturally aspirated.
But its 250cc.....you have to include the whole swept volume....not just the unported areas!!!

 

[Bellow]

Hmm ... a 2-stroke with a tuned pipe exhaust is arguably not naturally aspirated though?

Mere pipes - no moving parts. Show me a pump with no moving parts.

 

[BTB 500]

No forced induction = naturally aspirated.
But its 250cc.....you have to include the whole swept volume....not just the unported areas!!!

There is forced induction with a tuned pipe. It uses timed negative and positive pressure waves to first lower the pressure as the exhaust port opens to aid the exhaust/induction phase, then increase it just before the exhaust port closes for compression. It basically acts as a supercharger.

 

[Bellow]

No forced induction = naturally aspirated.

Agreed.

But its 250cc.....you have to include the whole swept volume....not just the unported areas!!!

Fair enough - if you include all two revolutions worth of swept volume with the 4-stroke. Won't happen but should. 4-strokes look really really lame if you do - I guess that's why it isn't viewed that way.

 

[BTB 500]

Show me a pump with no moving parts.

Pulser pump - Wikipedia

en.wikipedia.org

Multi-purpose V-Pump - The Water Pump Powered by Water

The V-pump exploits the extraordinary Venturi effect to help you empty water from your pond, pool, bilges, or dinghy, using only pumped water as its

www.baysidemarine.co.uk

etc.

 

[Bellow]

There is forced induction with a tuned pipe. It uses timed negative and positive pressure waves to first lower the pressure as the exhaust port opens to aid the exhaust/induction phase, then increase it just before the exhaust port closes for compression. It basically acts as a supercharger.

Then no 4-stroke is NA as they all (space permitting) deploy favourable lengths and volumes in their induction and exhaust systems to enhance torque production.

 

[Bellow]

Pulser pump - Wikipedia

en.wikipedia.org

Multi-purpose V-Pump - The Water Pump Powered by Water

The V-pump exploits the extraordinary Venturi effect to help you empty water from your pond, pool, bilges, or dinghy, using only pumped water as its

www.baysidemarine.co.uk

etc.

Do you have many engines that run on water? All of mine run on air.
I do concede your point that a tuned 2T exhaust systems acts as a pump - nonetheless, it isn't one. The turbocharger that sledders attach to the end of a tuned 2T exhaust systems is a pump. And with it, that engine moves from NA to forced induction.

 

[ALFAitalia]

Yep.....and a tuned two stoke pipes job is to try and use the pulses to keep the mixture in the bore rather than going straight out of the exhaust....so it stops loses rather than gaining anything......which they don't do a great job at which is why they are high polluting and thirsty and (without any variable porting YPVS type trickery) pretty peaky too as the exhaust pulses only work within a narrow rev range..
On my old RD 250 and 400 air cooled ones a throttle was not really needed....a switch would have done!....no power low down..or..all the power at once ....nothing in between! Worse than a 930 turbo!

 

[BTB 500]

Then no 4-stroke is NA as they all (space permitting) deploy favourable lengths and volumes in their induction and exhaust systems to enhance torque production.

4-strokes only use exhaust scavenging to improve induction. A tuned pipe on a 2-stroke actually forces air/fuel mixture back into the cylinder before the exhaust port closes for compression. That's forced induction

 

[ALFAitalia]

4-strokes only use exhaust scavenging to improve induction. A tuned pipe on a 2-stroke actually forces air/fuel mixture back into the cylinder before the exhaust port closes for compression. That's forced induction

No it isn't.....its forced exhaust gas speed reduction at best.

 

[Bellow]

4-strokes only use exhaust scavenging to improve induction.

That isn't true, Both induction and exhaust systems are very carefully designed to harness pressure waves generated by the gas exchange event. Witness Mazda's 'trombone' inlet tract on its Le Mans winning rotary engine (still a 4T) or the variable length inlet manifold (by flaps) on myriad production engines. It is just that 4T is less amenable to this than 2T (Mazda's rotary give a clue as to why)

A tuned pipe on a 2-stroke actually forces air/fuel mixture back into the cylinder before the exhaust port closes for compression. That's forced induction

It does quite a bit more than that but it is still NA. Not until a pump with moving parts is added can it be called FI.