3.0SC 180-188-204 bhp engine differences

911mot · 911mot's Garage

Can someone explain what the differences are between the 3.0sc engines from 79-83. What did they do to gain the extra horses? It went from 180 to 204 hp over the years. Was it just by raising the compression ratio? Thats the only difference I can see in the stats. Any differences in the fuel/ignition sytem. They all look the same!
Thanks as always

2.7RACER · 09-10-2005, 10:53 PM

From what I can tell, for ROW, yes the comp ratio 8.5:1 for '78/'79, 8.6:1 for 1980, and 9.8:1 for '81/'83. '78/'80 same cam and same cam timing, '81/'83 same cam retarded 6 degrees. According to Bruce Anderson the intake ports were larger for the early engines, valve sizes were the same. Interesting the USA and Japan motors for 1980 show a 9.3:1 comp ratio but only 180 HP.
I'm sure someone else knows more about this than me.

speeder · 09-11-2005, 12:18 AM

You are mixing together all of the 911SC motor specs; all U.S. cars were rated 180 HP DIN, (172 SAE), from 1978-1983. The early ('78-'79) cars had more torque, they actually had lower compression but bigger intake ports and intake runners than the later (U.S.) SC motors.

In 1980 the U.S. cars went from 8.5:1 CR to 9.3:1, but the intake ports were smaller. They also got a different version of the K-Jetronic Bosch CIS injection w/ lambda (02) sensor. Cam timing was changed as mentioned previously, but cams never changed.

The most potent SC 3.0 motor was the 1980-83 ROW version, which had 9.8:1 CR and the larger ports of the early motors. Those motors also had Mahle Nikasil P/Cs, which are superior to the KS alusil jugs on the later U.S. cars. The big port cars gain the most from SSI exhaust backdate as well. The later ROW motors are the most desirable all-around, IMO. They are the ones rated @ 204 HP, and w/ SSIs and a mild cam upgrade could be ~220 HP and still dead reliable.

hbkramer · 09-11-2005, 03:25 AM

Dennis , Lurking in the shadows, but appreciate your input. Thank you.
I have SSI' and need to get the oil lines and do the install on the 79SC . After your input I am really looking fwd to the SSI's and a Dansk 2 in 1 out set up.
.
Also noticed your 70 Bonneville ,I have a 8-9/10 2 owner stock bonney that I am looking to sell , whats your market like out there?
Thanks

K9Torro · 09-11-2005, 04:59 AM

Dennis

Are the specs you mention on the 80-83 ROW SC's the same as the 79 ROW SC the reason I ask is I have one and it is in the shop for a rebuild, any suggestions on a power up-grade that is still streetable and using the factory CIS ?

Thanks

Todd

jacko241 · 09-11-2005, 06:02 AM

Unless I am misreading Bruce Anderson's book, and that is highly possible

, the only years that had the big intake ports were 78-79.

andrew15 · 09-11-2005, 08:34 AM

Todd -
I have a set of 9.3:1 pistons (for nikasil cylinders) in great shape available - let me know if interested.

Regards,
Andrew M

K9Torro · 09-11-2005, 08:36 AM

Andrew ,

Sent you an email/pm

Todd

island911 · 09-11-2005, 09:17 AM

Quote:

Originally posted by speeder
You are mixing together all of the 911SC motor specs; all U.S. cars were rated 180 HP DIN, (172 SAE), from 1978-1983. The early ('78-'79) cars had more torque, they actually had lower compression but bigger intake ports and intake runners than the later (U.S.) SC motors.. . .

Now You are mixing things up.

It was the later ('80-'83) SC's which had more torque . . due to better combustion chamber mixing in the mid-range . . .due to smaller (faster) intake runners.

Don't know about the rest.

Noel · 09-11-2005, 12:43 PM

Another correction. The 1980 Euro SCs only had 188 HP it was in 1981 that they jumped to 204HP.