78-80SC Underpowered from factory.why?

[AUS911SC3]

Can anyone please tell me why the 78-80SC was down on power from factory compared to the later 81-83SC when supposabily the earlier SC ran better heads and CIS system?

[Oh Haha]

Are you referring to ROW 911s or USA bound?

What do you mean"down on power"?

[Kevin Stewart]

believe me an 82 sucks really bad to, my asnwer was a 3.6, Kevin

[sc_rufctr]

I think it's because Porsche like so many manufacturers want existing customers to trade up to the new models.

So when they release the new car it's down on power and as the years pass they up the compression a bit and with some other tweaks...
They magically come up with another 15 to 20 hp. Then the motoring journalists start writing about the new car and how "transformed" it is with the additional HP.

They are still doing it today with the water cooled cars... They all get progressively more powerful with each new model year.

The thing is modern cars are getting heavier and heavier. So in reality any increase in power makes little difference. Just ask any Subaru WRX owner... They early cars were light and agile. A real drivers car. The current model weighs nearly 300kgs more than the original. And as such has suffered dynamically. The engines have been "upped" in power but the earlier cars are lot more fun to drive. Does this sound familiar?

(By the way... if I had to drive Japanese car it would be an early WRX but I don't so my daily is a VW Golf VR6)

So in a word.. Marketing.

[WIL84911]

Buyer's guide states changes were implemented starting with 78 model due to Porsche's anticipation of worldwide emission concerns. Though hp was down it was still a 6-7 second car (0-60) unless I guess it's a CA model. The culprits -> air pumps, catalytic, EGR systems.

[Hladun]

8.5 CR doesn't help and CIS doesn't have accelerator pump. All to meet emissions.

[Kevin Stewart]

like i said the the cis 3.0 is way under powered, Kevin

[Gunter]

Originally Posted by AUS911SC3

Can anyone please tell me why the 78-80SC was down on power from factory compared to the later 81-83SC when supposabily the earlier SC ran better heads and CIS system?

US? RoW?

A US '80 SC is not the same as US '78-'79.

US '78-'79 = 8.5 CR
US '80 = 9.3 CR

The Euros had 9.8 CR, I believe.

We are talking about things as they were 30 years ago and wondering how or why it was then leads nowhere. The real question is: What do you want to do to get more power now with what you have?

I see by your previous threads that you have a Sportomatic? That doesn't help.
You also asked about building a SS 3.2.
Decide what mods you want to do to your 3.0 but be prepared that it'll cost lots of $$.
And changing the Sporto to a 915 is involved and costly as well.

So, what are your plans?

[Bill Verburg]

You have to put it in perspective and remember what the late 70's were like automotively. Emission regs were coming online in a big way and the technology just wasn't good enough. The manufacturers were scrambling to keep up and most were doing a miserable job of it. For it's day the early SCs were quite fast and good running cars.

[Forza]

Originally Posted by AUS911SC3

Can anyone please tell me why the 78-80SC was down on power from factory compared to the later 81-83SC when supposabily the earlier SC ran better heads and CIS system?

First, all US-spec SCs (1978-1983) were rated by Porsche to develop 172 HP (SAE J 245) at 5500 rpm, did they not? (see '72-'83 Factory Service Manual). Torque was likewise held constant at 175 ft/lbs @ 4200 rpm. Second, all SCs were equipped with Bosch K-Jetronic Continuous Injection System (CIS), although these systems were developed during the SCs lifetime to run without air pumps ('80-'83) and to provide better startup and drivability characteristics ('81-'83) thanks to an array of changes (e.g., increased compression ratios, K-lambda, different intake runners, temperature switches, acceleration enrichment, etc.).

As a rule, Porsche--like those manufacturers who actually race their product--designed engines that would permit further development. The SC's 3.0 was hardly unique in this regard, as the engine itself essentially combined aspects of the S and Carrera engines that preceded it to create a virtually bulletproof powerplant, with its 180 HP (DIN; US-spec) representing 15 more than the '77 S but 20 fewer than the '77 Carrera.

As for the SC being "underpowered", it was hardly labeled as such by reviewers at the time. On the contrary, the SC was universally praised for delivering no-fuss high performance while conforming to stringent emissions requirements.

[jsveb]

Hi

I've been wondering about SC power levels back when I was researching prior to buying. Today I own a Carrera 3.0 (1976), great engine. The 1978/9 SC engine is virtually identical when talking power potential, the only immidiate difference is cam timing (and some other stuff: bearings etc.). The compression is 8.5 (ROW) as the 930/02 (Carrera 3.0).

There has been speculation as to why the SC was down rated from 200 (Carrera 3.0) to 180 in 78 and 79. Some think is was due to the fact that back in the day the CO of Porsche put his "money" on the 928, and that he didn't want the 911 to be able to out perform the newcomer, since the 911 was supposed to go out of production anyway -NOT, customer demand saved it. The CO got sacked.

I have driven both an SC and my Carrera 3.0. I don't think it is (in this case) about HP, but responsiveness.

Just my story... Thanks for listening.

Jesper

[Steve W]

How would Porsche continue upselling new cars if they gave everyone that 4.0 back then?

[ARCSinAK]

Are there any clear threads on how to bring a US 3.0 up to a EURO SPEC motor? Is there a difference between a Euro sc and 3.0 carrera or was it the same engine?

Seems like there is a bit of grey area in the 1st steps to upgrading a stock 3.0....... Step up to a 3.2 SS...964 cams ,SSI and Exhaust....increase CR ... no CIS.....Just wondering what is the single most cost effective ways to increase HP on a stock 1980sc.

Your thoughts are welcome..

JS

[flat6pilot]

Headers ($ your choice)
Exhaust ($ your choice)
Bitz EFI kit ($2000)

[Forza]

In Chapter 11 of Streather's Porsche 911SC: The Essential Companion, he discusses how the quest for big gains in output from US-spec SC engines is a very expensive proposition. Sure, there are common stage 1 modifications such as air filters, exhaust headers, and mufflers, but anything more than these will start getting pretty expensive, with somewhat limited returns. Ultimately, one would be better off picking another 911 model (a grey market Euro SC or 3.2 Carrera, perhaps) or transplanted engine to use as a base for modding.

A US-spec SC is the Hermann & Attwood of the 911 line: The 4.9s may be faster, but the 4.5s can go the distance!

[Tsunamiboy]

Under powered or not, I seem to get in a lot of trouble with my 79SC. Got pulled over for the third time in 12 months this Saturday (got a warning). It gets up to 90mph damned fast and without much effort. I'd be screwed if I had a 3.6L

[snbush67]

Originally Posted by Tsunamiboy

Under powered or not, I seem to get in a lot of trouble with my 79SC. Got pulled over for the third time in 12 months this Saturday (got a warning). It gets up to 90mph damned fast and without much effort. I'd be screwed if I had a 3.6L

Me too! Seriously, how much more power do you need in a street car? Underpowered?

But, to add to the topic, the factory seemed to always low ball the numbers. And if the SC didn't have to spin a smog pump and an AC, and haul around all the other Al Gore BS, then it would have made progressively better numbers.

[Gunter]

Originally Posted by snbush67

Me too! Seriously, how much more power do you need in a street car? Underpowered?

And if the SC didn't have to spin a smog pump and an AC, and haul around all the other Al Gore BS, then it would have made progressively better numbers.

Sounds real progressive, duh........

Nothing like stuck in rush-hour traffic sucking in the fumes from the polluter in front of you thru the A/C or otherwise. Without the Al Gore BS, or any emission control whatsoever, gaging and burning eyes would be so much more enjoyable.

SoCal, especially L.A., is a paradise for exhaust-fume-lovers.

We need more Intellectual Giants par example making decisions about air quality.

[Superman]

I didn't read through all the replies, but by now someone should have brought you up to speed. All SC's were specified with the same hp rating (180). Early SC's had fatter intake ports and fatter intake runners. But later SC's had higher compression pistons (9.3:1 compared to 8.6:1). As far as your expectation that early SC motors will make more power, I'll have you know my late-SC motor made the most power of several 911's one day at the chassis dyno, including a Carrera. My motor has 20/21 cams and SSI's.

[Superman]

One more thing. Ignition timing is retarded from the factory. My ignition timing is somewhere near five to seven degrees more advanced than factory spec. Some engines will handle 35 degrees full advance and some will ping/knock. The ones that can handle the advanced timing will be noticeably stronger.