52 replies to this topic

[Ali_G]

I know at the moment that engines have their engines mounted in a V shape with an angle of 72 degrees. Why not make this angle greater. This would lower the centre of gravity and make the car better aerodynamically.

Ali_G

[desmo]

Ferrari have done exactly that. I believe their v-angle is 90 degrees presently. The problem is the wider angle makes the engine physically larger and, as well, the exhaust routing becomes problematic at larger angles. You begin to run into aero package compromises as the v-angle opens up.[p][Edited by desmo on 08-29-2000]

[Ursus]

I heard/read somwhere that Renaults new engine will have 110deg V angle. I can't remember where I heard it but I reacted on the angle, it seems very wide.

[McBain]

I could be wrong on this, but I think that I have read somewhere that the natural angle for an engine in determined by the number of power strokes per cycle. For a v10 this is 5, divide that by 360 degrees and you get 72. So the v angle for a v10 should be 72 degrees to get a natural balance. As you deviate from this angle, balancing becomes more of a problem!

I believe that renault is bringing their 110 degree engine in for next year. This should be very interesting.

McBain

[Ali_G]

I also read tha t Renault have been testing heat resistant materials since they left F1. I believe that they left F1 with intentions of a quick return. These in the engine would reduce the need of a cooling system as they would not over heat as easily as normal materials. That would make the car lighter. THe sidepods could also be lower which would help with the aerodynamics.

Ali_G

[Ray Bell]

There's no doubt that taking 5kg of coolant out of the block and heads would make for easier balancing of the package.

[Vitek]

You're right McBain. I read an online article that compares the balance of differently configured engines ie: inline 6 to V6.
Visit: http://www.fortuneci...ine/smooth1.htm
To maximise the average torque output during two cycles of the crankshaft, the pistons should be staggered in the same way that you suggested.

[Billy Gunn]

Hi Guys - It's good to be back after such a long time away!

I heard that Renault will use a 144 deg vee angle and will use a silicone based coolant system to run the engine at 150 deg C +. This will allow minute radiators and cut aero drag, as the higher coolant input to the rad results in more efficient cooling per square inch of rad core.

Ceramic based MMC pistons and valves will stand these higher temperatures. Watch out for similar materials for the head. Upper / lower C/cases could also be steel (0.040"-0.060" wall) within a few years!

Oh! and watch out for the EAV - this could be one reason for the initially wide vee angle, maybe not next year, maybe a couple seasons on. I reckon on it being a race between BMW and Renault to the EAV!

Billy G

Where's my ole' matey boy Art got to??

Hangyerganzyontneckiesneck.

[desmo]

BG,

Great to have you back! I think Art was taken aback at the response to his reports of his own death turning out to have been rather exagerrated.

144 Degrees? Where did you hear that? That's getting the exhaust plumbing about as close to the ground as is feasable, given the miniscule clutch diameters.

I was going to be the t*rd in the punchbowl and report that composite pistons are illegal, but I went back and re-read the regs and lo and behold:

5.5.2 ) Pistons, cylinder heads and cylinder blocks may not be composite structures which use carbon or aramid fibre
reinforcing materials.

As long as one doesn't use CF or Kevlar, it appears to be OK to use composite pistons.

AS for steel cases, why not? Center to center piston distances could probably be reduced making the engine more compact. Also, shorter cranks and cams can run in smaller more efficient bearings as well as, being smaller, producing less internal friction which has become a major issue at the crankshaft speeds of today. Do you think that it would be feasable to cast a case in steel with thin enough wall thicknesses to fully take advantage of steel's much higher modulus of elasticity and yield strength? Or would we be looking, possibly, at a return to the fabrication, such as those by M-B, of the past? Likely a combination of the two I'd think.

EAV? I'm off to do some digging.

Again, welcome back,
Kurt

[desmo]

EAV= Eletromechanical Valve Actuation? God, I hope Renault are still pushing that envelope. All the published literature I have read are really skeptical about it's present suitability for high RPM operation. If Renault can make the concept work in F1, it will be the largest leap in engine tech since Herr Otto. Perhaps Piezo-actuator stacks, as opposed to conventional solenoid-type actuators?

How would these influence the V-angle?

[Ray Bell]

Billy Gunn! How nice to hear from you again! desmo, what was that question we had for him?
I've sent you a personal message, Billy, so check it at the bottom of the forum display page, some personal stuff for you that doesn't belong on the thread.
I really can't see EAV being a real go, myself, the weight must be a killer, surely?
And where do you get all this info? Got links within Regie Renault itself?
Art still contacts me privately.

[desmo]

BG,

By silicone-based coolant, may I assume you are referring to PG? It's high boiling point (187C) is attractive as a coolant as it isn't subject to the formation of local vapor pockets which cannot efficiently dissipate heat, but it is only about 2/3rds as thermally conductive as water. Might you lose some of the advantage gained by the higher boiling point by virtue of this property? Perhaps I should start a thread devoted to issues raised by going in the direction of an adiabatic engine.

desmo[p][Edited by desmo on 09-08-2000]

[Billy Gunn]

Desmo,
Well if a silicone based coolant (be it PG, or similar) could be enhanced to increase its thermal conductivity you would have the ideal medium!
I think steel c/cases could be used as there now exists some pretty wacky stuff, almost impossible to form, except by 'exploform', and a whizz to weld. Wall gages as low as 0.040" would have similar to greater strength than aluminum castings at 0.100" wall thickness. And as you rightly point out cylinder centers could be reduced.

BTW - like a good journalist, I could never reveal my sources!!!!!

Ray,
Where's that personal message??? I'm not that computer literate - [probably on a par with Arty!]

Cantthinkofnoclosinline!

Billy G

[Billy Gunn]

Ray,
OK found it!!

'Donotcrossmeridian'
Billy G

[desmo]

I wonder if F1 teams are presently using a fairly conventional water/EG blend as a coolant. I posted a pic of the MP4/13 and you could see the coolant was a very blue color in a sight glass by the water radiator.

Steel is overlooked as a high tech engineering material nowadays. Where space is at a premium and a high modulus of elasticity is critical, there is still nothing better as a material. A French company named Excel produced some tubesets for racing bicycles made of a very exotic steel with a yield strength exceeding 200,000psi(!) in the eighties. The unbutted central portions of the tubes used wall thicknesses as little as 0.4mm. I'm not sure if they're still in business, it's been a while since I've heard anything about them. I've heard that casting these high-strength steels without any voids is really a tricky business. I wonder if it would be feasible to cast a c/case out of exotic steel[p][Edited by desmo on 09-16-2000]

[davo]

One of Cosworth's strengths has been its foundry and cutting edge tech on steel and steel casting.

In F1 the success rate of casting is probably irrelevant and with Xray inspection the one good casting among many flawed ones can be found.

One of the things now being done with high tech castings is vacuum. Exposing the molten steel to vacuum prior to the pour tends to pull any disolved gases out of it, and the mould itself is under vacuum.

As always it will be interesting to watch the technology

[ehiwario]

in 1991 the sauber mecerdes sportscar had an engine at 180 degrees. this reduced center of g but had several lubrication problems. due to inertia they could not get all the oil around

[Powersteer]

Widening the angle of the vee will make the engine heavier because you get a less compact block. The lowering of the vee in f1 is fine tuning the package.

[Halfwitt]

Powersteer,

Widening the block and making it slightly heavier as a consequence isn't too bad. The cars are very underweight anyway......Look at the amount of ballast run. Also, the cylinder heads would be much lower and I would think these wouldbe quite heavy, especially when full of cooling fluid. If the centre of gravity is lowered to give an advantage, the teams would go for it every time. 72 degrees is best for a V10, but Ferrari run 90, and the new Renault is alleged to be 110, this will be to gain some advantage from lower C of G and possibly some aerodynamic advantage also.

[Powersteer]

Don't worry half wit, i was just mensioning bout one dissadvantage. Firing order timing too has to be changed calling for more weight through the crank unless they dont mind the uneven firing order. Just rememeber that uneven firing order means a stronger crank shaft which is heavier, ciao.



I can't argue against widening of the vee, why? Because F1 teams are applying it!






[p][Edited by Powersteer on 09-26-2000]

[DangerMouse]

Coolent in all racing cars/bikes in restricted to water and water alone (most antifreezes etc are too slippery and do not evaporate.)
The only reason I can think of for Renault to run such a wide V angle would be to cool the cylinders - yes a return of aircooled engines! they'd loose about 100BHP but the aerodynamic advantages would make up for that, the engine would be heavier but the loss of the cooling system would save the differance. Wide V angles (ie almost flat engines) actually increase centre of gravity as the casings have to be stronger to support the two banks of completely seperated cylinders, Renault must be up to something revolutionalry.

With the current rules banning ceramics a true adiabatic engine is not possible in F1 - air cooling makes sense!

With currenr CNC machining sticking to the old rule of thumb for cylinder angles to naturally balance engins is no longer necessary, the required firing order and balancing weight to counteract vibration can be machined into the crankshafts these days, meaning that we no longer have to stick to 90,180 or 270 etc degree crank angles.

[koenda]

Hmmm... aircooled engine....

don't think so.

The area that is required to cool the engine would be far too high for a formula one engine. "Rule of thumb" for the cooling power of an engine: about the same as the Output power.

You can derive the power that is produced by the burning of the fuel by the amount of fuel and fuel lower heat value. About 1/3 of it is actually used, about 1/3 goes in the cooling system and 1/3 exits through the exhaust.

So for a Formula one engine the cooling power is (probably larger as) 600 kW.
Aircooled engines also cannot be kept at a stable temperature, liquid cooled a little better...

[Billy Gunn]

Hi Koenda,

That's an interesting heat balance! 1/3rds all the way thro.
What about radiated heat? And isn't exhaust heat balance higher than 1/3rd, like closer to 1/2??

The art of getting heat dissipation into a coolant medium other than (but also including) water, is to control the flow rate. Now engine coolant pumps have for a long time been mech driven from the crank at a fixed ratio. Electric water pump(s) would allow better energy management, by only running the pump(s) to their best flow vs. heat pickup characteristic. Staged pumps are more efficient than one single pump sized for max speed/flow. These electric pumps can be run by the control system which will be monitoring the coolant system, and working off 'heat maps' generated in the empirical data of the controller.

The coolant may well only run in the cylinder heads, the blocks could be air and transfer cooled (the lube oil can take care of all the heat generated from the piston). 144deg bank angles give even fire, a low profile, good separation for air cooling of the block, and leads to a drastically different intake regime! This later point may be one reason why Renault has bought a team - getting a team to buy into a drastically different intake geometry could be difficult - when you own the team - its no big problem!
I think we may be seeing the demise of the air intake over the drivers head and the whale back engine cover could also disappear with a wide angle engine - this may result in a flat backed with higher outer fins engine cover which could have big influences on the rear wing efficiency. This also helps package the EAV system.

[DangerMouse]

Liquid cooling is conveniant. it's ability to cope with heat soak and the ability to have the devices that radiate the heat away from the engine positioned remotely, plus the surface area of the cooling system can (tranditionally) be far greater than that of the cylinder block and cylinders themselves is all great.

However given that the F1 car nearly always has a decent airflow over it, heat soak shouldn't be such a problem, and if it is, with a liquid cooled solution water boils causing pockets of steam in the coolant leading to hot spots and resultant gasket or engine failure anyway - for a liquid cooling system to be effective it's capacity has to exceed normal cooling requirements significantly - which isn't efficient.

With modern manufacturing processes air cooled block/cylinders/heads could be made with massivly greater surface area than was possible 10 or 20 years ago - definately worth trying.

[desmo]

Good stuff here. I hit the road for a couple of days and the place is blowing up with interesting posts!

DangerMouse, it makes some sense to mandate water only as a coolant as puked EG or PG would surely make the track more dangerous than simple water. But then why is the coolant clearly visible in the sight glass beside the catch tank in the image below bright blue? Anticorrosives with dye to make it easier to tell if it has been added?



Well I just checked the tech regs for F1, and there are no coolant restrictions. You can run any coolant. Hmmmm...

[koenda]

I haven't that much experience with Otto-engines but with a turbocharged dieselengine, we computed that the output power was about 33%, exhaust "power" about 36% and the coolant "power" was about 30%.

I have looked it up in Heywood, and he says:

SI engines at maximum power
Brake power: 25-28%
coolant power: 17-26%
Misc. : 3-10% (heat rejected to the oil, convection and radiation)
Incomplete combustion: 2-5%
power in exhaust: 34-35%

so my "rule of thumb" isn't that bad at all ;)
But this is for normal SI engines. I don't know if it can be used for Formula One engines, but I guess it isn't that different.
How do you plan on cooling the oil? A larger quantity of oil is required if you want to cool the pistons with it, otherwise the temperature would be too high. (This combination is formerly used on Suzuki-motorcycles, but they converted to liquid cooling.)
Specific heat of water: 4.18 kJ/kgK
specific heat of air: 1 kJ/kgK
therefore should the cooling area with air be 4 times as big as with liquid cooling. (that's why you have those big radiators, with a very large coolingarea ;)) the convection in water is also 30 times as big as in air, so with air only the air direct in contac with the cooling area is heated, while in water the water that is not in direct contact heats up quicker.
If you use pressurised liquid cooling, you can run it at higher temperatures (because of the higher pressure the cooling liquid doesn't boil at 100°C) this increases efficiency because of the higher temperature difference in the radiator.[p][Edited by koenda on 09-28-2000]

[DangerMouse]

desmo, maybe it's just dye to make sure mistakes are not made with levels? I can't find any particulars in the regs except the maximum pressure allowed in the system (3.75 bar) however I believe normal race rules come into play here that is only water can be used.


RE the cooling thing, if you could produce an engine that doesn't require as much cooling (ie it runs much much hotter.) then air cooling might be sufficient - water cooling wouldn't as F1 cooling systems are restricted to a certain system pressure to avoid "super-cooling" solutions, inorder to cope with a much hotter running engine without the water boiling at it's current pressure would require a lot more water capacity. (and weight.) and even more drag to cool it.

The oil already does a large amount of the cooling in any engine, the Suzuki "oil-cooled" engines are nothing more than air cooled units with a bigger oil reserve and oil cooler! Which is basically what I am expecting from Renault except the Renault will (hopefully!) be a half way house between the Suzuki SACS units and an adiabatic engine - which is all we'll ever manage given the material restictions in F1.

All speculative of course - but I wouldn't expect anything less from Renault! - what we do know however is that it'll be 10 cylinders boring FIA.

[Billy Gunn]

Koenda,

Ok, but my Symonds chart shows differences between CI and SI engines. I'd agree with the 27%-28% usable power, but the split for radiated is close to 8%, oil and water 25%, exhaust 36%, and unaccounted 4%. There will be some closed loop heat accounted for in fuel vapourization, etc,.

The pistons already use oil squirt jets underside to keep temperatures manageable (if they don't they sure oughta!). So there would appear to be little heat input into the 'block' over the ring travel area. The '97 Judd had no coolant other than in the head (but then the ring travel area was in the head!) - it's only a small step to delete coolant from this area and use air cooling, then concentrate on the coolant in the head.

BTW I don't think these engines carry agreat deal of coolant, my bet would be system capacity as low as 4-5Lts on current engines.

[koenda]

Dangermouse>
I don't know if the oil-coolers are liquidcooled or aircooled. But you have to get rid of the extra energy that has been put in the oil by using it to cool the piston etc.

But running the engine at higher temp is not a valid explanation for converting to aircooling. The liquid could have a higher velocity, a higher massflow and therefor still run at the same temperature. But effectively, the same amount of energy has to be given to the environment to keep the engine at the same temperature (or even less because the convection, radiaton etc. terms are getting larger).

That's why I mentioned the SACS, I wonder why they converted to liquid cooling when they increased the specific power ;). But the energy that should be absorbed by the cooling substance is the same. I haven't studied heat-tranfer, but I know that the cooling power depends on the cooling area and the massflow of cooling substance (and specific heat and turbulence in the boundary layer)

BG>
As I have worked more with CI engines, I use that "law of thumb". But as you can see, the amount of cooling power is about the same as the output power (28%/25%). This is at full load. In part-load, the coolant/brake power is about 2-3, but then you don't have that much brakepower.
The oil also has to be cooled, so you need radiators or liquid/liquid cooling. radiators increase drag, and liquid/liquid cooling needs liquid cooling ;)

In stationary diesel engines they use a shaker-piston design to cool the piston. An amout of oil is situated in the piston and is accelerated, at the TDC the oil splashes against the piston-bottom and cools it. Then it is replaced. This has a larger efficiency than squirting. (j.f.y.i)

[DangerMouse]

koenda, The main reason I should image for Suzuki to drop the SACS eninges (well from sport bikes anyway) was more to do with weight and size, as the SACS lumps are basically aircooled engines with enhanced oil cooling, they have to have a lot of metal in them to A. rediate hear and B. deal with heat-soak without warping, weight is a major factor with bike engines. (BTW Suzuki SACS engines fire oil under the piston crown too!)

Modern F1 cars are so underweight you could afford to give away 20KG on the engine if it was going to save you significant amounts of drag.

if your heat output is beyond the capibility for the liquid cooling system to soak up the heat you can circulate it as much as you like it won't make any difference! Volume of course does the more water there is the more area there is to soak the heat away but liquid cooled systems are not good at radiating heat away, you need radiaters that need air forced through them - this costs drag and increases the frontal area of the car - if the engine could radiate most of it's heat away (being ait cooled) and the heat is taken away by incidental airflow around the engine you'd have a huge aerodynamic advantage.

You'd need to make siginicantly denser and physically thicker blockes heads etc. if you wanted to run the engine at much higher temperature (just to deal with the extra expansion and to avoid hot spots by conducting heat avay quicker) that means a heavy engine - if you've gone that far why not make it a bit heavier still and make it air cooled?

[koenda]

Dangermouse>

You have to have the airflow over the engine. You have to direct the airflow to the center of the engine to have the aircooling you want. This also increases drag and disturbs the airflow at the back, which may increase drag also.
I don't know if this option decreases drag. You need the liquid-cooling for the heads, and probably the oil-cooling as well, so you have to have radiators. You could decrease the area if you use aircooling for the liners, but then you have to have another airflow under the body to direct the air to the cilinderliners.
My guess is that you could better have a little more radiator-area and a little more water than another disturbing airflow. (which interferes with your airboxdesign...)

[DangerMouse]

koenda, as long as you get the materials right you shouldn't need to cool the cylinders at all, only the cylinder heads and even then, if you could get rid of the horrible poppet valves (which don't have contact with the cylinder head long enough to dissipate heat very effectively, then I should imagine you wouldn't need to cool the heads either.
Direct Injection would enable the hotter engines to run with out pre-ignition/detonation problems which would otherwise occur being that the engines must run on petrol.

[koenda]

okay, then you don't have an aircooled engine, but a liquid-cooled. So no return of an aircooled engine.

[DangerMouse]

No, I reckon what I already said a hot running air cooled engine (As I don't personally believe an uncooled engine would be possible with the current regs, but that is of course debatable.) with perhaps no cylinder cooling, the wide angle would be to run the heads inline with where the sidepods are now.

[desmo]

This from Flavio Briatore at the Friday press conference in Japan on 2001:

"we will have a completely new engine, which will be quite difficult to fit in the car."

[Billy Gunn]

Desmo,

Looks like my source on this one was spot on!
As I said, 144deg V10 with the air intake drastically rearranged, to form a low back just behind the driver. This should entrain more air for the rear wing.

[Powersteer]

144° is 36° off being a fully horizontal engine which is at 180°, devide 36° and you'll get 18°, thats 18° off the groud. I know it'll support the firing order as 72° plus 72° but i think 144° is over the top. It is officially stated at 110° by Renault(i think). A very wide vee won't help chassis designers to keep weight down especially when weight will always be up. Ciao




[p][Edited by Powersteer on 10-06-2000]

[desmo]

BG,

Reading the bodywork regs gives me a headache, but the not inconsiderable upside of the airbox arrangement you describe as far as allowing less impeded airflow to the rear wing may be tempered by them. I'll go back and re-read them and try to visualise how they would affect an arrangement such as that.

I sent you a PM about the email you sent.

"Rocky Rococo, at your cervix."-Rocky Rococo

Regards,
K

[desmo]

Mike Gascoyne, Jordan's former technical director who is still on 'gardening
leave'
before he takes the reigns at Benetton/Renault, applauded the theory
behind
AMT's new powerplant. He also warned other teams and manufacturers
that they
may have to follow AMT's lead.

"You have to run to stand still in Formula 1," he said. "And if this [AMT's]
engine
works, then everyone will have to follow the same path."

Anyone know anything about this "theory"? I believe he is referring to an evolution of the engine slated to appear in '02. The Renault may not be the only "new" concept engine being sprung in the next couple years.

[david_martin]

This is a bit off topic, but what the heck.

Mike Gascoyne was on leave. It was just announced that Jordan have released him to Benetton effective immediately. It seems that, for once, Flavio Briatore and Eddie Jordan have manage to come to an agreement without a judge being involved!! (Remember the Micheal Schumacher and Giancarlo Fisichella sagas).

So the 2001 Benetton or Renault or whatever it will be called may have a bit (or more than that) of Gascoyne's input. How he and Pat Symonds will get along is yet to be seen. But the new Renault works engine, and Gascoyne's input (particular on the aerodynamic front) might make for a new challange to Williams BMW for the "most likely next programme to climb to the top of the slippery pole" award as the Ferrari/Maclaren programmes get to the end of the omnipresent five or six year cycle of F1 dominance.

[Halfwitt]

Originally posted by desmo
"You have to run to stand still in Formula 1," he said. "And if this [AMT's]
engine
works, then everyone will have to follow the same path."

Anyone know anything about this "theory"? I believe he is referring to an evolution of the engine slated to appear in '02. The Renault may not be the only "new" concept engine being sprung in the next couple years.

From what little I have read, the only revolutionary thing about the AMT engine is that it will have no service life after a race, i.e. no practice mileage left, no parts servicable at all. If it remains anything to do with the recently dire Peugeot effort, then it might well be doomed.

I have no feeling for what is conventionally done with F1 engines. I assume that for some engine suppliers, some parts such as some castings, and maybe something like crankshafts may be used for extra mileage over and above the race distance itself. I bet some of the big budget teams are already operating on these grounds, i.e. scrapping most stuff. But I would be interested to know what (if anything) is re-used (even if for practice sessions) in an F1 engine. i.e. would a crankshaft run for 2 races??

[PeterK]

just a fun thought - why not a 288 degree v? i.e upside down. You could use as much coolant and h(eav)y stuff as you want, because its only 1 inch off the floor and very wide. Cast Iron cylinder heads etc
Maybe intake air comes from the ground and helps ground-effect (with a bit of inertia/vortex cleaning like my vacuum cleaner).
A lightweight crank would be nice.

[koenda]

you don't want the air to be sucked from underneeth the car. This way the engine can't get enough air, so the power wil rapidly decrease. You will also need a very good airfilter with all the dirt on the track.

(btw. the V-angle is defned as the smallest angle between the cilinder-banks, it's just called an inverted V. The Germans had inverted V-engines on their Messerschmidts)

[Apollo4]

First off, let me say this is a great forum. I've purposely been putting off registering knowing how much time will be taken up between this forum and the Nostalgia Forum. Oh well, who needs good grades anyway?

I digress...

First off, the somewhat famous internet gasoline FAQ that's been around almost as long as the internet has always quoted the Honda F1 Turbo engine from 89 as the most efficient ICE ever made with a brake power efficiency of 32%.

http://www.cs.ruu.nl...-faq/part4.html

Secondly, as far as cooling needs go, wouldn't it be logical to assume that as ceramic coatings get better, more heat will be rejected into the exhaust instead of the engine coolant? If you coat the piston, valves, ports, etc.. theoretically the heat stays in the air, and is then rejected from the exhaust heat. As a result you can run smaller cooling passages, and not need to reject as much heat through the radiators. right?

On the other hand, it was once again Honda during the turbo years that actually increased the charge temp to increase efficiency and to help atomize the dense toluene fuel. What was the more primary concern here? Atomizing the fuel, or increasing efficiency?

Finally, ignoring all the above on ceramics, wouldn't higher engine temps lead to a less dense intake charge because it is hotter, thus less power? Or does the air not stay in the intake long enough to absorb any significant amount of heat from the engine at high rpms? I remember reading in Race tech an interview with Judd about F1 engines, and he commented that detonation was not a problem at the rpms these engines run even with the less than ideal combustion chambers..

[Ray Bell]

Any problem would be a problem, methinks... and 'less than ideal' combustion chambers would not win races.
At 17000 rpm, the time the charge is left standing in the inlet tract is not very long.. it's all happening at 283 revolutions per second, so think in terms of less than 100th of a second...

[desmo]

The combustion chambers that win F1 races could well be characterised as abominations as far as their shape. The surface to area ratios are terrible, the flame paths are laughable, it is a tribute to the upsides of these tortured shapes that they are the best compromise available. The ideal combustion chamber shape would be a perfect sphere.

[Ray Bell]

Theoretically, yes, but with compressions ratios of today, that thinking has long been left behind. More important, I would reckon, are things like swirl and complete combustion.

[MrAerodynamicist]

I'm not to hot on engines design, so Q: whats the "rule" for the way the angle effects power? Whats the best theoretical angle?

[csilva]

It is very interesting what was said here about increasing the V angle in F1 engines but nobody said anything about lubrification problems. The discussion has been all around Thermodynamics related problems, but what about the problems you get when trying to make your lubrification work well in an engine with a very big V angle ? I remember very well the problems BMW had in the turbo era when they inclined their
4 cylinder engine to fit it into the "revolutionary" low center of gravity Brabham (in 1986). I heard they had all type of problems and never managed to get the lubrification system to work well. I know the turbo engines worked at higher temperatures then the actual V10, but in the present F1 engines the oil system seems to be more complicated since in works at much higher pression levels than before.

I would like to have some comment on this. Specially from you guys that work with or study internal combustion engines.

[desmo]

I think the problem with the BMW turbo was laying down a design that was originally meant to be upright. If it's a clean sheet design, there are no real problems with either power or lubrication from a wide angle-V. The boxer 12 Ferrari designs were both fast and reliable.