Is the 3.2 (Max Moritz) upgrade really worth?

[Leo]

Hi,

I have my US spec 83 911sc's engine out and I'm at the point of choosing either to go with the Mahle 98mm p/c upgrade which is a 9.8 compression or just keep the 3.0 with the 95mm cyl and bump up the compression to 9.8 or 10:1 with new pistons.

I've read you can get 230hp from a 3.0L with the SSIs, 964 cams, larger ports, and complete euro CIS. 230hp is about what I'd get from the 3.2 upgrade.

Is $3k on p/c really worth in this case? Is the HP gain minimum?

ps. I already have the euro CIS and the SSIs.

Thanks Guys,

Leo

[Eagledriver]

Why not save the money and just use your old cylinders. Only you can decide if the upgrade is worth it. Are your old pistons worn out? New pistons to bump compression from 9.3 to 9.8 aren't going to give you a noticable change. Going to 3.2 will give you a proportional increase (around 20 HP). What do you want from your car? Unless you race you'll probably be happy with your engine either way.

[ChrisBennet]

Did you see this dyno thread ? It seems to have mods similar to what you are contemplating (98mm P&C,9.8:1CR).
-Chris

[Bill Verburg]

Displacement on a 911 is expensive hp, cams and compression offer more bang for the buck on the smog motors.

That said torque is really nice on a street motor and displacement is the best way to get it.

I did the upgrade from 3.6 to 3.8 and feel that it was well worth it

For a track car gearing is probably a better way to go.

[Leo]

Noah,

I saw your dyno chart and thats the sort of horsepower I'm looking for it. I guess I can reach that with the 3.0L. I also have a pair of 40 webers that I can put instead of the CIS. By the way, did the Carrera 3.0 come with the same large intake runners/ports as the early SCs?
TIA,
Leo

[rdane]

I have a 3.4 being finished up as I type this. I went from a 3.0 and 182 hp at the rear wheel to a 3.4 with 98s and a 3.2 crank.
I have the larger runners and stayed with CIS.

I dyno'ed my car several times as a 3.0 and will make a direct comparison once the engine is broken in.

I did think it was worth it if the engine needs to come apart. I had a oil consumption problem that I wanted to fix. Turns out it was a set of bent valves.

The dyno link is extremely dissappointing for numbers as they are just a tiny bit above my original engine in HP and not a huge jump in torque. I would like to see that car on a dynojet so we could make a better comparison.