Schuey

what would be the benefits of going with a Mahle 3.2 piston/cyl set (93010398910) on the my 3.0 case? with 10.3:1 compression...

what else would I need to do?

I have a chance at a deal on a like new set (NOS) for $1500 is this a good deal?


from what I understand this is a complete high compression (10.3:1) setup with pistons and cylinders...in my ever search for more power and good deals I thought I may just buy these...it's from the local (3hrs away) porsche dealer...I thought I'd add my PMO's, swap out my pistons/cyl with these and bam...power

cobalt

I had a set of these on my 1979 911SC widebody. Still to this day the best Porsche I have ever driven. Power was comparable to an early turbo with amazing torque. Easily broke the 255s free. Faster off the line than the turbo but not as fast once moving. The car only weighed a little over 2300 pounds so this might have had something to do with it.

I would highly recommend it if you have the money to spend. I bought the car in Zug Switzerland already built so I cannot tell you what also you would need to do. Other than a set of SSI's and a nice free flow muffler. I don't know about you but the SC cams have the nicest power curve and in my opinion a 3.0 with the 3.2 upgrade is far superior to any 3.2 Carrera engine (sorry guys).

JonM..

Schuey,


ErHmm, Cobalt the SC and Carrera had the same cams. The SC has inferior injection and smaller valves and ports. So how on earth would a SC with the euro pistons be superior to a Euro spec Carrera 3.2? I think the weight of your old car is scewing your perspective.

Steve Weiner-Rennsport Systems

Shuey:

Thats a very nice upgrade and will make a very big difference.

A few things,.....

1) This kind of displacement and compression changes will require more fuel delivery into the engine to prevent excessive cylinder head and exhaust temperatures. Your PMO's will need a jetting change.


2) Compression ratios over 9.8:1 require either twin-ignition or unleaded race gas. Without either one, you'll face broken rings and trashed pistons from detonation. BTDT,.....SOOO many times. 93 octane fuel is not sufficient.

3) I'd use either Solex, "S", or GE-40 cams.

Don't despair; done properly this is a really really good setup,....

cobalt

JonM'

I never said the Carrera cams were different. The Carrera used the SC cams with a 3 degree advance. Yes the Carrera had slightly larger valves and ports along with electronic management. Yes this made the Carerra an all around more reliable car. IMO it is this reliability that Porsche achieved that took something away from the character of the car. Once again IMO. The CIS is a great injection system just not as reliable. It is not inferior.

It is very hard to explain the feeling this modified engine gave without having the car to let you drive. I have owned many Pcars and driven both stock and modified SC's and Carrera's. For pure driving pleasure the modified SC wins hands down IMO.

The larger 3.2 L(98mm) 10.3 to 1 compression ratio, redesigned piston allowed for the makings of a very powerful engine. The euro CIS distributor with the 3.2 pistons and cylinders pumped out over 230 hp add the SSI, B&B 4.5 inch dual exhaust, permatune ignition bumped it up to over 250 hp. The design of the heads were different than the Carrera's. This engine generated more torque than that of the Carerra about 230 ft pounds.

This combined with a car weighing in at just over 2300 pounds made for a car that accelerated from 0 to 60 in under 5.0 seconds and would lead an early turbo up to 90 mph when the turbo would gain about a car and half length up to the cars top speed of about 160 mph. I had the opportunity to drive against a very nice euro 73 RS on the Autobahn for about an hour or so and easily out accelerated and out powered him.

Maybe it was the valve advance that I felt made the difference in how the power came on maybe the added torque. But side by side my opinion was I would take the modified SC with the 3.2 P/C over a Carrera engine. Sometimes acceleration numbers and performance don't reflect pure driving pleasure. Sorry it is just my opinion based on my experiences. You may feel differently.

Anthony

cobalt

Yes I agree my engine had the euro fuel distributor which flows quite abit more fuel. I did not have dual ignition but did need to use the highest octain fuel and used a (cheep aproach) octain additive along with hotter plugs and ignition. I had installled a cylinder head temp gage and monitored my temps never had a problem. I did have a modified front end with twenty tube racing oil cooler.

emcon5

Just to clarify, these are 95mm or 98mm?

Tom

cobalt

I believe the 95mm were the 3.0 liter the 98mm are the 3.2 liter. I am going off of memory, most of which is twenty years old now. One other thing I forgot, to keep temps down The Stock SC fan housing (smaller Dia) was replaced with the larger housing and different pulley ratio. It's been so long I don't remember the specifics. I do remember running 100 degree track days at LRP and never seeing oil temps over 200 degrees or cylinder head temps above 250.

Although everyone will tell you this upgrade should only be done with carbs. The euro CIS did a very nice job. There may have been more work done than mentioned but in nineteen years of owning the car the CIS was flawless. Always started instantly, never gave me problems and was great in traffic. One side note I got about 6 mpg city and upwards of 30 mpg highway.

Schuey

Steve, thanks for chiming in, I hoped you would...so in your opinion...could I...

take my 3.0 stock engine:

1) add these
2) rejet my 46 PMO's
3) run 94+ octane

and have a really good setup?

or should I twin-ignition it?

emcon5

If we are talking about stock piston/cylinder sets, they are both 95mm, the 3.2 having a longer stroke. A stock 1984-1989 95mm 3.2 set will not work in a 78-83 3.0 L engine without changing the crank and rods. The wrist pin sizes are different, and I believe the wristpin offset is not the same.

From the looks of things, people are assuming that he is talking about a 98mm set. I don't think that is the case, based on the price, (a new 98mm Mahle set is ~$3400) and the part number. I can't find the number in the factory parts list, but Vertex shows it as for "PISTON & CYLINDER SET 3.2 EURO" fitting 84-89 911s.

This was also covered in the pelican thread on the same subject.
http://forums.pelicanparts.com/showt...hreadid=146989

Schuey, again, this is a stock euro set for a 84-89 Carrera? If the answer is "yes" it will not work. It can be made to work, but not drop in like you seem to want to do.

Tom
(Short stroke twin plug 964 cam CIS 3.2)

cobalt

I agree,

I was assuming he was talking about the 98mm set made for the 3.0L engine. That was the set used on my engine. The work was done in 1983 prior to the Carrera even being released. $3400 is quite abit of money before you have even removed the engine.

Steve Weiner-Rennsport Systems

Shuey:

LOL,..Bottom line:

If you use a CR over 9.8:1 on these big bore engine, you MUST run twin-ignition with any pump gas.

Failure to do so has very expensive consequences. I see many engines with broken rings and hammered pistons,.......all detonation-triggered damage.

cobalt

Steve,

What else might have done to my engine that would have allowed me to drive it all these years without problems. I did not drive the car that much maybe 45,000 miles over 19 years. When i sold the car it had good leak down and compression. I used a boroscope to look around and the insides looked new. I alwys ran the car hard. Redline every shift. I always used the best gas I could buy. When i bought the car in europe they recommended 101 octane which was readily available. Here it was 93 or 94 octane. with the additive (if that actually does anything) Any comments why my engine ran so well.

Thanks

Steve Weiner-Rennsport Systems

Hi:

From here,...(Portland, OR) I could not speculate on why your motor did well.

There are so many variables at work that any guesses would simply be speculation.

USA Gasolines are not consistent nor can they support engine configurations like this without assuming a great deal of risk. If someone is willing to take the chance, that's their call of course,...

I do know what I've seen over the past 30 years builing 911-based engines and IMHO, its just foolhardy to rely on one's ears as the defacto "knock sensors" for detonation detection. I'll tell you that this methodology doesn't work,....

cobalt

I understand. That is why I always kept an eye on things using a borascope to look around.

The engine was built buy an x factory Werks mechanic. I guess now they call it the Exclusive department. He apparently had something to do with the RS/RSR projects. (so i was told)

I was just wondering if the factory new some tricks back then. I vaguely recall the original owner saying something like modifying the heads to make the CIS work with this set of P/C's. It's been too long to remember the details.

thanks anyhow