Difficult HP?

say you had a 6 liter V12 rev limit 9500 how difficult would it be to get 1200 HP on pump gas? say 93 octane..

I see that the Chrysler ME 4-12 has a 9:1 compression ratio and up to 20 PSI of boost on pump gas .... i would think that you would get lots of detonation.

If you have a good engine design there are no problem to reach that.

WRC engines are using compression ratios over 10:1 with boost pressures of over 2 bar running a fuel which is only RON 102.

thats cool, but what are the technical aspects involved with getting and engine to run at those specifications?

Dished pistons and shallow valve angels to improve the quench area? Probley involves making the combustion surfaces smooth and flowing..

Piston probley has a hemisphearical dish with a flat surface around the outside in contact with the cylinder wall.

ahh still groggy.

Can you be a bit more specific as to where your question applies?
Race cars have a lot of tradeoffs for high HP that make them very impractical for a street car, etc. etc.

You mentioned pump gas with 93 Octane, this assumes you would be running on the street? (1200 hp implies drag racing, as it seems impractical on anything other than a diesel locomotive)

It takes a lot of good parts to make an engine (especially the valve train) run reliably at 9500 rpm. The detonation part is tunable, the 9500 rpm is not.

"Guessing" a high rpm peak torque at 9000 rpm, you would be making ~700 ft.lbs. of torque. Assuming you are talking about a street car, I would think this is would overpower your entire chassis and drivetrain. So, major mods (major work) here too.

Also, 102 octane racing fuel is not comparable to 93 octane pump gas.

Well, we have the Bugatti W16 engine that is making 1000 hp from 8 litres of displacement, I assume that it runs on 93 pump octane. A 1200 hp version is said to come.

The valvetrain isn't a problem, 9500 rpm isn't that high revs. And there's always the desmodromic system if conventional springs or airsprings wouldn't be enough.

To make the engine resistant against knock the pentroof chamber will get you a long way. Slanted squish can also be added which increase power and reduce the risk of knock. Pistons in turbocharged engines usually use an inverted dome design with cut outs for the valves if needed.

With higher compression ratios like in NA racing engines the piston design usually looks like this
http://hem.bredband.net/b132378/annat/ferrari.f1-2000/engine07.jpg
http://hem.bredband.net/b132378/annat/ferrari.f1-2000/engine10.jpg

Well seeing as how supercars now have ever increasing Hp and reduced weight i'm shure 1200 HP isn't that impractical. We all want street cars with that much i think :)

Id prefer to make most HP high in the RPM range so you could use gearing to place the torque where you want it.

with 1200 HP at 9500 RPM you would be making 200 hp/liter which is quite high i think.

I would think it would be best to have a dished piston, although i'm not shure how this effects combustion if the quench area gets compressed closer and closer to the center of the piston... do you want a large flat quench area or a gradual sloped quench like i described?

is it better to have combustion takes place in the cylinder head or in a dished piston?

does the desmodromic valve system cost more or less HP than the spring return type? I don't think it would effect the basic use of DOHC and Variable cam overlap. Umm Elimination of valve float :iceslolan.

Desmodromic should take less power than steel springs, airsprings also takes less power due to decreased friction.

The pistons on the pictures above, which are from Ferraris F1 engine use slanted squish. The squish zones are slanted to match the combustion chamber in the cylinder head. This increase turbulence and don't mask the valves.

200 hp/liter is high for a NA engine at these speeds, I would guess that around 1100 hp is max for that configuration. Then with an engine which is almost dead until it reaches higher speeds and also will be damaged by even the slightest overreving.
With a turbocharged or supercharged engine it's no problem to get the 1200 hp.

yeah it's a huge ask to get get an N/A engine to do 1200hp even with 9500 revs and 6 litres...

i doubt the bugatti engine would put out that power on 93 octane fuel... or it'd have to inject a heap of it just to avoid detonation etc. i think i have this round the right way... i always get knocking and pinging mixed up... oh well

i think a street car with that much power would be plain scary... i prefer the light weight option with around 600hp.. ala McLaren F1...

The Bugatti W16:
Volkswagon engineers needed 4 separate turbochargers, 64 valves, 4 continuously variable Cams, and 2 computers per cylinder bank to control it all. And one heck of a cooling system, i"ll bet. This is most impressive, but far from an easy thing to do.

What is the redline for this motor? (Peak power is around 6000 rpm's?)

yeah it's a huge ask to get get an N/A engine to do 1200hp even with 9500 revs and 6 litres...

i doubt the bugatti engine would put out that power on 93 octane fuel... or it'd have to inject a heap of it just to avoid detonation etc. i think i have this round the right way... i always get knocking and pinging mixed up... oh well

i think a street car with that much power would be plain scary... i prefer the light weight option with around 600hp.. ala McLaren F1...
The Bugatti is a road car, it shouldn't need anything more than normal fuel.

Knocking is mainly a problem at low engine speed with highly boosted high compression engines running lean with a high spark advance.

Knocking and pinging is the same thing. Pre-ignition is however a different issue. Knocking always occur after ignition.

I suppose engines operating at underboost and high rmp probley have a large conrod:stroke ratio, as i have read larger is better at least for supercharged engines.

Anyways limited to current working technologies, what would you use in your V12?

Valve trains, Cams(phasing), cylinderheads, combustion chamber, thermal coating, design...Alloys(Vanadium,beryllium-Magnesium,aluminum-lithium)

I had not heard of Desmo, untill SaabJohan mentioned it... anything else that seems cool?

Mabey a Titanuim-nickel/cobal tungsten ceramic turbocharger turbines something like that could withstand temps up to 3000 C+. :iceslolan

We always like to think about our own dream car that hold some awesome figures but its the technology that gets you there... i wanna know more automotive tech stuff.

yeah but 93 RON isn't even good pump fuel...

obviously it has to run on regular fuel but i'd say premium... like 96 or probably 98...

I suppose engines operating at underboost and high rmp probley have a large conrod:stroke ratio, as i have read larger is better at least for supercharged engines.

Anyways limited to current working technologies, what would you use in your V12?

Valve trains, Cams(phasing), cylinderheads, combustion chamber, thermal coating, design...Alloys(Vanadium,beryllium-Magnesium,aluminum-lithium)

I had not heard of Desmo, untill SaabJohan mentioned it... anything else that seems cool?

Mabey a Titanuim-nickel/cobal tungsten ceramic turbocharger turbines something like that could withstand temps up to 3000 C+. :iceslolan

We always like to think about our own dream car that hold some awesome figures but its the technology that gets you there... i wanna know more automotive tech stuff.
A larger rod to stroke ratio is better for high speed and supercharged engines (turbo is a way of supercharging) since they have their peak cylinder pressures later. A larger ratio does also decrease maximum acceleration.

Just use the same basic design that any high performance engine is using and it will be ok.

Thermal coatings should not be used in the cylinders, but they can be used on exhaust valves and in the exhaust manifold.

Typically aluminium is good as a head/block material, but a block could also be made in thin wall ultra high strenght steel. Aluminium-beryllium is mostly for pistons and so on but it can also be used in blocks and heads at a huge cost.

Turbocharger can be made with a magnesium compressour house, thin wall stainless steel turbine house, Mar-M 247 or TiAl intermetallic turbine, impeller of aluminum or titanium or possibly TiAl if it's a high pressure ratio compressor. A superalloy single crystal turbine should be possible to make but at what cost? TiAl are mostly used with lower temperatures while the directionally solified alloy Mar-M 247 is used with inlet temperatures of up to 1050 degC.

Besides using them coating on the cylinder walls their application can be used on non-friction surfaces... valves, cylinderhead, Piston face, ect...

Its said that an engine with a larger displacement per cylinder has a higher thermal efficiency but with them coating you could have a smaller displacement cylinder as or more efficient than the larger.

http://www.hotrod.com/techarticles/51120/

Sry, my bad yea you can't really have TBC's on cylinderwalls :P if metals wears the coating would be gone fast.