Hot 2 liter engines

[raspy2point2]

So anybody know the difference between a 2 liter 911S engine and the Carrera 6 race engine ? Chris

[rower]

My guess is similar to 911r engine with Dual ignition, titanium connecting rods and triple carburettors, had a power output of 210 hp at 8,000 rpm. Vs 180hp.

So basically the 2 liter S comes on at 4,000 while the 906 must come on at 6,000 rpm.

[66S]

About $100,000

[sithot]

My guess is similar to 911r engine with Dual ignition, titanium connecting rods and triple carburettors, had a power output of 210 hp at 8,000 rpm. Vs 180hp.

So basically the 2 liter S comes on at 4,000 while the 906 must come on at 6,000 rpm.

From my lone experience in a 911R: "Yes". Not much of a street engine unless riding around in 2nd gear all the time is your thing.

[beh911]

Decent chart, has a couple errors if I recall. I believe this is from Anderson's 911 Performance Handbook

[Schläfer]

A 2 litre production S engine makes 160hp, if you’re interested in what a modern 2 litre 911 will put out, you should take a look at the European 2 litre cup series. It’s really pushed the engine development along. The rules have been through a couple of stages because many of the cars came from different series, so to get them all in the grid together, there had to be some flex. For the first year this allowed the use of large S valves, although now they have to be small valve and they’re never been allowed twin plug and have to use Solex carbs, but the outputs are impressive. There’s some in car footage on YouTube, they sound amazing.

[rower]

Yes, you are correct. I spaced.

The carb versions 160hp. The 1969 mfi 2 liter 170hp. And there was a higher output 180hp in 1969 too but wasn’t the standard S motor.

[Bullethead]

A 2 litre production S engine makes 160hp, if you’re interested in what a modern 2 litre 911 will put out, you should take a look at the European 2 litre cup series. It’s really pushed the engine development along. The rules have been through a couple of stages because many of the cars came from different series, so to get them all in the grid together, there had to be some flex. For the first year this allowed the use of large S valves, although now they have to be small valve and they’re never been allowed twin plug and have to use Solex carbs, but the outputs are impressive. There’s some in car footage on YouTube, they sound amazing.

Is that the Peter Auto series?

[TargaFlorio]

As others have mentioned before, lots of differences. Here are the main ones:

- Carrera 6 had a different case from 2.0 911S
- Solid valve gear (the rockers didn't have the adjusting nut at the end) which used shimmed tappets to adjust for valve clearance. With solid rockers engine was good to 8000RPM (incidentally, Porsche used the same solid rockers on all their race engines, all the way up to the 962)
- Larger valves, larger ports
- Different pistons and barrels (CR over 10)
- Center lubed cams and different cam profile (more top end horsepower)
- Twin plug ignition
- Taller intake manifolds
- 46 instead of 40 Weber carburetors

Later on C6 engine used fuel injection which was good for another 10 hp or so.

To my mind the biggest difference is the solid valve gear, without it all naturally aspirated aircooled 911 engines are done at 7300 RPM.
As with any naturally aspirated engine, revs are your friend!

In terms of being tractable, I think most people exaggerate how peaky the S or R or C6 engines were. Having driven all of them (on track and on street) they're just great fun. Yes, you shift a bit more (compared to a torque engine) but so what, to me that's what makes it interesting.

My 68T Sports Purpose is a blast to drive on the street. It's a 2L alu case with S pistons & barrels, S valves, T ports (which lowers the torque curve), T crank (spins up quicker), 40 Webers with large 34 mm venturis (jetted accordingly), 68S ignition (Bosch distributor with points etc.), free-flow intake and open rallye exhaust. It's perfectly fine in traffic and once you get to 5K RPM it wants to go again and pulls to 7300.

If you want to ruin your street car, just put a lightweight flywheel in it - but revs never hurt anyone

Ciao,
n.

[Schläfer]

To my mind the biggest difference is the solid valve gear, without it all naturally aspirated aircooled 911 engines are done at 7300 RPM.

I can't fully agree with that, the 2 litre cup cars all rev to 8k, they're not using solid rockers.