Has anyone just bolted Webers onto a 2.7 CIS engine?

[keitho64]

Rich - Do you need me to bring the gtech or do you have one?

Ryan - If you car is running so good, I would be tempted to say leave it for now. Research all you can on the 2.7 and when time comes for the rebuild you can address the pistons and cylinders. However, one important note to remember, if you cannot get the fuel in and out fast enough everything else is pointeless. On my 2.2T motor the PO ported the heads to S specs which I think is the reason it runs so good. When you do plan a rebuild, start with the best heads possible as that is where the power comes from.

I remember seeing pictures of you car on other posts and it is very clean, I say drive it an enjoy it. My car has a little 2.2 and I cannot drive it to its' limits. I can get in a lot of trouble fast enough as it is now.

[Rich911E]

Ryan:

Ditto to what Keith said -- drive it and enjoy it. Having the car torn apart for months to gain 20 HP would be a waste of good driving time. Spend the money on doing some driving schools and that car will be a lot faster than it would ever be with 220HP.

If you are going to do the engine project, I would buy a late model 2.7 liter engine (they are so cheap it is not funny) and plan on rebuilding it while you are driving the car. Then it is just a weekend swap. Personally, I would stay with the 2.7 for the simple reason of weight -- the aluminum case engines are much more durable but they are significantly heavier. More weight out over the rear end is not where the 911 needs it. Contrary to popular opinion, the Webers are not really problematic once you get a good tuning procedure. My car starts right up and idles fine. I would definitely get with the larger port heads. You could probably find a used 2.7S spec motor for less than $1000 as a core and start from there. The 32 mm ports have a cross sectional area of 804 mm2 where the 35 mm ports have a cross sectional area of 962 mm2 -- an increase of about 15% which is going to make more of a difference the more cam you use and more RPM you use.

Also, make it is as light as you can. Light is always better.

Hal: Thanks for the kind words -- it is a better combination than I thought it would be. Loads more torque than that 2.0 liter. I didn't change the pistons because I didn't change the cams. The compression ratio is about the same with the CIS and RS pistons (8.5:1) and the CIS pistons actually have a slight swirl effect to them which might help a bit in the lower RPM (pure speculation). The RS pistons are necessary if you change the camshafts because the CIS pistons do not have enough room to accomodate the increased valve lift.

When I change to the E/S cams, I will put in the wedge dome JE pistons. The wedge dome pistons are like the Max Moritz pistons and improve the shape of the combustion chamber near the spark plug and provides improved flame travel and you don't get all the shrouding of the backside of the pistons that necessitates (or at least favors) the dual plug ignition. If I stay under 10:1 (crummy 91 octane!) and use the wedge dome pistons, I can avoid the twin plugging and mega-expensive ignition system.

Keith: I have the G-Tech still in the box. The car is up on ramps and waiting for the master cylinder. I will try to put it in Wednesday or Thursday night, so the car is ready when you are here.

Rich

[bigchillcar]

DD74,
Go to the link at the bottom of my signature to see my Pelican gallery.

Keith,
Yep, I'll keep researching the idea...lloks like I'll have plenty of time if she keeps runnin' sweet! I'll bet that 2.2 sounds great!
Ryan