Horsepower?

[draab29]

how much horsepower can be squeezed out of a 3.2? Assuming NA, no forced induction, all other options on the table.

[jcge]

What level of reliability are you looking for, application, duration between rebuilds etc ?
Think in terms of Hp/liter of displacement - between 90 and 130 per liter, depending on what you're trying to achieve.

[Geronimo '74]

Originally Posted by jcge

What level of reliability are you looking for, application, duration between rebuilds etc ?
Think in terms of Hp/liter of displacement - between 90 and 130 per liter, depending on what you're trying to achieve.

Wow, 130HP per liter (NA ), that is really really high.
I believe a Honda S2000 has 120 per liter and I thought that was almost a record for a street car (production car)

[jluetjen]

Yes, but the S2000 can be driven cleanly on the street. A 911 motor making 130 HP/liter will be an all-out race engine without the driveability of the S2000 motor. The $/HP/liter for the S2000 will also be a lot lower then the 911 motor. The S2000 motor just starts out as a more efficient motor because it's got a 4-valve, penta-roof combustion chamber, variable valve timing and water cooling which combine to result in an engine with a higher CR, better breathing across the rev range, better combustion quality and lower emissions.

In it's day in the late '60's, the 2 liter 911S motor compared very well with F1 engines of just 10 years earlier, even more so when you compared the 906 variant with F1 motors from the 50's. At the power densities of the time, the air-cooled 911 was often better off since it wasn't consuming HP driving a water pump for the cooling system. As power densities went up in the 70's, air-cooled engines fell off the leading edge of performance. Excepting the variable valve timing and advanced coating technologies, the S2000 engine really isn't a lot different from an F2 engine of the '70's, which was half of a Cosworth DFV grown by .5 liters.

[jcge]

Geronimo

"Assuming NA, no forced induction, and all other options on the table"

90hp per liter would be considered a very hot street motor (unlikely to meet emissions, at least in my local area) and 130 is track only, limited life..

Consider the 1970 912 engine (in terms of air path and combustion chamber design.....MFI, slide valve, 2 valve, comparable ports, twin plug, and stroke/rod ratio)

5.0L @ 630DIN hp = 126HP/litre @ 8500 rpm

That was the early 70's.....there have been developments in control systems, cams, materials since.

130/liter "Assuming NA, no forced induction, and all other options on the table" is achievable.


(C) IME 1972

[longhornchris04]

Street or track? Emissions? Fuel options?

You can get a hell of a lot of power if you have:

1 - High/Very High compression + twin plugging --- race gas required
2 - Hot cam w/ associated high-rpm valvetrain
3 - High strength engine components to handle the high RPMs
4 - Lots and lots of cooling
5 - Spark management or full engine management (TEC3 for example)
-- bonus with full engine management- opens up options for less restrictive intake manifold
6 - Race exhaust... headers to "muffler"
7 - Lots of Dyno time tuning the crap out of the engine.

Of course, if you do all this your engine will need race gas to not self destruct, have a really high idle, and probably be a dog at low RPMs, but would likely haul at high RPMs.

Good luck...

[Steve@Rennsport]

Originally Posted by longhornchris04

You can get a hell of a lot of power if you have,....

1) A great deal of money,....

[longhornchris04]

Originally Posted by Steve@Rennsport

1) A great deal of money,....

Yeah, that too.

"Money can't buy happiness... but it can buy you really fast car, and that might do the job.