Us spec 80 3.0 questions
 

Thanks in advance for all of your time and knowledge. First of all I feel fortunate just to be have the pleasure of 911 ownership. I have a few questions in regard to which avenue to take on my 80sc with 114k on the clock. I have spent many a hour reading about various methods for increasing HP, its frustrating to have one of the only motors that was detuned, the Eruo had more juice, the carrera 3.0 , 74 carrera ect.
So far I have installed SSI and a Dansk 2 in one out, adjusted the valves , cam timing she runs strong and feels much better.

I don't have the finances at the moment to do a complete rebuild and punch it out to a 3.2 or 3.5. I don't have smog to deal with, not so sure I want carburetors, Whats the opinion on looking for used Euro pistons or some larger port fresh heads maybe twin plugged if I increased compression ratiochanged p/c. How about 3.2 induction?

Ideally I would like a 3.6 but that seems like 15 to do it right, turbo breaks, beefing up the 915 and the tub ect.

Anyone have any ideas

Regards

Js

Put a 3.2 in it, sell the 3.0 and youre part way there.
The Carrera 3.0 is an 8.5 cr engine, basically a 78/79 SC.
Bruce

the 80SC may have the 9.3 CR. It should if it is a US model. Also it should have the small port cylinder heads and small CIS runners (2R). If it does, changing to say 964 cams or changing p&c to 3.2 liter to make a short stroke is not the best solution without getting bigger runners and change the heads. Doing all would be expensive and you might be better off by getting a 3.2 Carrerra engine.

I have the 80 year 9.3CR SC engine and small 2R runners and same exhaust as you, but I also installed EFI which gives it much crisper throttle response which makes it feel like a bigger engine. I also lightened it some by removing AC, stereo and small bits I don't need for my usage. The combined effect of the modifications I have done is the car has 20Hp more than stock and it feels decent quick. And I got to keep my beautiful 3.0 engine !

I would go the same route again.

Dont bother with the euro pistons. They are hard to find and very expensive for little gain.

Look at Al's efi thread (http://forums.pelicanparts.com/porsche-911-technical-forum/573869-my-triumph-speed-triple-project-update.html) if you are really serious about using the 3.0. Otherwise, save your pennies, go to DEs, and buy 3.6 conversion parts when they come up in the FS pages. Then if you still want more power in the same car buy that 3.6 and make the swap. :)

-Michael

I have a different idea: Look for some used '78 or '79 heads, JE 10.5 : 1 pistons assuming your cylinders are Mahle, 46 mm Webers with GE 60 cams. You'll have to twin plug it either with distributor or crank fire. I can tell you first hand this motor kicks ass. All up you could do this for about $6,000 if you do the assembly work.

Here's what one looks like:http://forums.pelicanparts.com/uploa...1307490858.jpg

Subd

Thanks Lindy

Lindy's motor is sweet ;) The Dist. is a big chunk of the cost so there are some less expensive alternatives you could also apply if you were cost conscience... but nothing looks as sexy as a twin plug distributor!

Regarding cost, there have been a couple of crank fire twin plug set-ups for sale in the classifieds here that were very reasonable. The way to make a 3.0 talk back is to add compression and cam overlap but to do it you have to twin plug. A lot of people here told me GE60 cams would not be happy on the street but it turns out they are great. The motor acts near stock until you get to about 4500 rpm. You need to make sure it's pointed where you want to go because when it comes on the pipe it really flies. It's 0-100 as fast as you can grab the gears.

Lindy