best 3.6 engine improvements

[philippeF]

Hello
May you tell me the best improvements over stock for the 1990 3.6 engine ?
regards
Philippe

[widebody911]

How much are you willing to spend? Are you willing to open up the engine? Daily driver? Track car?

Seeing as you're in France, maybe on-board fire suppression?

[philippeF]

without opening the engine....track only

[CBRacerX]

Change the exhaust to 993 HE and your choice of custom muffler setups. Or, if heat is a non-issue headers are a great option.

[Steve@Rennsport]

Phillipe:

For a 964 3.6:

1) Software

2) Headers and a good muffler

3) MAFS (requires matching software)

4) Cams (RS ones since you cannot go bigger with your single-throttle intake) Cup cams require the MAFS.

5) 102mm P/C's

6) 993 RS intake valves

Be sure to upgrade the valve springs & retainers for track usage.

[philippeF]

thanks, do you mean the 993 valves have a different profile/shape ?

philippe

[KobaltBlau]

I think the 993 RS intake valves are just lighter, but of course Steve knows better.

[Steve@Rennsport]

993 RS intake valves are larger and well worthwhile when different cams are installed.

[philippeF]

larger diameter ?, big job to change valve seats.....

[KobaltBlau]

you can do steps 1-4 without taking the heads off, of course.

Once you are taking the heads off for 5 and 6 having the seats changed while you're having your heads re-done is not such a huge leap.

[Steve@Rennsport]

Originally posted by philippeF
larger diameter ?, big job to change valve seats.....

Nossir, the seats are the same; you'd need to have someone experienced at this that will machine them to fit.

We do these all the time,.........

[KobaltBlau]

Clearly I know nothing about the big motors. thanks for the straight dope, Steve.

[JonT]

Steve--can you give more info on the 964 upgrades? What does this get you over the stock 247hp 3.6 and what is approx cost of these upgrades?

[Steve@Rennsport]

Originally posted by JonT
Steve--can you give more info on the 964 upgrades? What does this get you over the stock 247hp 3.6 and what is approx cost of these upgrades?

Hi Jon:

As you probably know, the 964's were not blessed with Porsche's best exhaust system design and the 993's clearly showed the potential with their separated, dual system.

We've seen power increases in the 25-30 HP range with a properly designed set of header/heat exchangers and a good muffler.

Software changes do not result in massive HP bumps; its a modest increase, but does sharpen throttle response and it becomes an integral part of the whole suite as long as a chip is properly programmed and good gas is used. Chips are like people; some are better than others,.....

Cams and big valves enhance the mid to upper end and usually add somewhere around 10-12 HP. There are variables here based on accuracy of the valve job and valve timing.

Not long ago, we did an '89 C4 with a custom chip, MAFS, a header/heat exchanger system with dual-in muffler, RS cams and valves that made 292 HP. Not bad for an otherwise stock 3.6.

Please e-mail me directly for further information.

Hope this helps,

[Bill Verburg]

I agree exhaust comes first
use 993, B&B or other 41mm - 45mm primary header

The 993RS valves are good, both intake and exhaust are Na filled, and nicely sized they are expensive and have stems which are ~1mm smaller than the 964. So all the guides will need to be changed as well, might not be a bad idea to do that any way

another option for valves at a much more reasonable price and w/ a bigger selection, is some nice undercut ss valves, they will be ~ 1/2 the price ofthe 993RS valves, or you could go crazy w/ Ti versions for 100% greater cost.

the cam selection will be limited by the intake setup, for stock barndoor or 993 style hot wire, a hyd RS or mechanical SS cam is near the edge of what can be used. If you use one of Steve's spiffy intakes or TWMs there is much more that you can do.

lastly there ain't no replacement for displacement some nice 102mm p/c will be felt everywhere in the rev range.

Once all of the other stuff is taken care of a chip burned for the package as it sits in the car is the icing on the cake.

Of course mopstof the above means opeing up the engine.

[philippeF]

that's really helpfull, thanks for sharing...
Philippe

[Marv's3.2six]

A simple but overlooked mod is to have your fuel injectors match flowed. This will check and adjust the spray pattern, flow rate and electrical characteristics of your injectors. I had mine done and the before flow rate varriance was 12% from worst to best plus the spray patterns were quite varried before match flowing! Now everything is within .005% of each other.

[drsimonwong]

PhilippeF,

Try this UK site.

http://www.porschetuning.co.uk/html/modules.php?op=modload&name=NinemeisterContent&file=index&req=viewarticle&articleid=20&topic=4&articlename=Tuning%20Guide:%20964%20Carrera2/4

Simon

[stevepaa]

I am just finishing my engine rebuild after a year and will drive my 92 C2 for a while before I fiddle with it again, but where do I find pariculars on exhaust changeout? thanks