MarinS4

Should read "retro fit cam gears". Early style cam gears allow for more precise cam timing.

trophy

As MarinS4 has mentioned, A compression bump and some happier cams goes along way in waking up these engines. As Steve W will attest to, the stock compression on these engines is never much over 10.8:1 a long way shy of the advertised 11.3:1.

Gaining that 'loss' back and some cams that open her up makes a significant difference and the spend is substantially less that a full displacement build (which should also include cams etc).

I am personally a fan of happier cams that the RS, however that does bring about a need for solid lifters and could make it a challenge with any smog testing requirements.

As for turbo's etc, it really comes down to cooling design and execution, heat is a killer for turbos and doubly so for air cooled engines, substantial oil cooling and intercooling is a must, many guys on the 993tt forum know the right formula, MarinS4 included.

I love turbo Porsches, however on the track there really is something special about a camed NA engine running to redline...

Silver Surfer

How do you get a compression bump without installing new pistons and/or cylinders?

trophy

The old school method of decking can be done to an extent, however there is a limitation to ensure the deck height is still within spec. Steve W would have better knowledge here on how much can be achieved (if any) here.

Compression is driven by piston and heads, and their relationship, you could put new pistons in exiting cylinders, that would be the best/cheapest way to go.

Silver Surfer

It seems surprising to me that a .5 increase in compression (10.8 to 11.3) would make a substantial difference in performance.

IainM

Magen you multiply by 3 cylinder per rotation and 6800 rpm it all adds up😀

Cemoto

Fixed that a little to meet my sentiments!

:-)

Steve Weiner-Rennsport Systems

There is, but an accompanied increase in octane requirements.

The latter is problematic in most parts of this country.

JPS

And Steve, isn’t compression the result of a whole bunch of upgrades? You don’t just swap pistons, correct?

Silver Surfer

im in Seattle, isn't 92 octane ok?

Steve Weiner-Rennsport Systems

Compression changes mainly come from using different pistons since deck height isn't adjustable on the 3.6.

Steve Weiner-Rennsport Systems

92 is OK for a stock compression engine.

Super90

Getting my motor back soon. 1990 model. New Mahle P&C's and over-milled the heads slightly. Reportedly 11.05 to 1 on compression now. Stock cams. Running 93 octane and getting Steve Wong to do his magic.

Any issues with this that you see Steve Weiner ?

Tremelune

Am I naïve to think this can be accomplished by bolting on a Varioram intake and associated bits to a '95 motor? Maybe a computer change?