US to Euro engine specs

[carrera73rs]

I have an 81SC, the US version puts out 180 HP, and the Euro version puts out 204 HP. Can anyone tell me what the differences on the engine are to give it the added power, and is it relatively easy to do if emissions testing is not a factor?
Thank you for any suggestions

[911st]

Some feel Porsche may have managed the numbers given for HP at bit so they may not be a great compairison.

Most of the differance is a bit higher compression, less restrictive exaust w not cat, and I think the later Euros have the biger port heads and intake like our 78/79's. There are some other small differances with the injection with the WUR I think.

I am not totaly sure on this.

[175mph951]

i believe the cam timing is a bit more advanced also

[SpeedracerIndy]

911st pretty much covered it as far as what I know.

Higher compression (9.8:1), larger intake ports (I think), larger fuel distributor, larger fuel lines, premuffler instead of a cat, more advanced cam timing. Also, the CIS system is very similar to the 78/79 us CIS. There is no O2 sensor.

I would think there are many things you could do to a US spec 81 that could get it to the euro HP levels that are much cheaper than trying to adopt all of the euro bits. SSIs for example would get you most of the way there.

Also 930/10 euro motors require 93 octane fuel, whereas the US spec don't. That means if you are in an area where you cannot find 93, you are still safe to run 87 and don't have to worry about your engine grenading, whereas I'd be screwed!

[Bill Verburg]

Originally Posted by carrera73rs

I have an 81SC, the US version puts out 180 HP, and the Euro version puts out 204 HP. Can anyone tell me what the differences on the engine are to give it the added power, and is it relatively easy to do if emissions testing is not a factor?
Thank you for any suggestions

For MY81 USA use 930/16, RoW use 930/10
first and biggest mechanical difference
/16 has 9.3cr and probably KS p/c
/10 has 9.8cr Mahle

second fuel pump cut off is electronically governed
/16 6500+200
/10 6800+/-200

third
/16 has a cat and uses 91 unleaded
/10 has no cat(premuffler) and uses 98 leaded

4thwhile the cams are the same cam timing on /10 is retarded 6* from that used by /16
/16 IO 7*BTDC
/10 IO 1* BTDC

5th the fuel and ignition are tuned to different specs.

[carrera73rs]

Thank you to all that answered my question

[SpeedracerIndy]

Originally Posted by Bill Verburg

For MY81 USA use 930/16, RoW use 930/10
...

second fuel pump cut off is electronically governed
/16 6500+200
/10 6800+/-200

...

I realize this doesn't really pertain to the original post, but I feel this could be important to anyone who has a euro SC and might be reading this.

One thing I have to disagree with is this part about the electronically governed rev limiter. My 930/10 has a rev limiting rotor. Everything I have been able to find out about the euro SC's is that they all had a rev limiting rotor and were not electronically limited by a relay or the CD box that cut fuel. When I replaced my rev limiting rotor with a normal one it happily revved, to my surprise, above 7,000 rpms. I promptly replaced it with a rev limiting rotor from a 930 (7,000 rpm as the original 6,800 rpm rotors are hard to find here in the US for reasonable $).

[Bill Verburg]

Originally Posted by SpeedracerIndy

I realize this doesn't really pertain to the original post, but I feel this could be important to anyone who has a euro SC and might be reading this.

One thing I have to disagree with is this part about the electronically governed rev limiter. My 930/10 has a rev limiting rotor. Everything I have been able to find out about the euro SC's is that they all had a rev limiting rotor and were not electronically limited by a relay or the CD box that cut fuel. When I replaced my rev limiting rotor with a normal one it happily revved, to my surprise, above 7,000 rpms. I promptly replaced it with a rev limiting rotor from a 930 (7,000 rpm as the original 6,800 rpm rotors are hard to find here in the US for reasonable $).

the specific mechanism for rev limiting is certainly different on the non cat engines but both are electronic in nature. The cat equipped cars use a fuel pump strategy, the non cat cars use the distributor rotor mentioned here. Notice the different specs for +/- between the 2 different engines?

the fuel pump cut off is thought to protect the cats better than the rotor interrupt which allows raw gas to be be dumped into the very hot cat. There were lots of problems w/ cat meltdowns back in '75 when cats first became widely used in the automotive world.

[arrivederci]

Originally Posted by SpeedracerIndy

I realize this doesn't really pertain to the original post, but I feel this could be important to anyone who has a euro SC and might be reading this.

One thing I have to disagree with is this part about the electronically governed rev limiter. My 930/10 has a rev limiting rotor. Everything I have been able to find out about the euro SC's is that they all had a rev limiting rotor and were not electronically limited by a relay or the CD box that cut fuel. When I replaced my rev limiting rotor with a normal one it happily revved, to my surprise, above 7,000 rpms. I promptly replaced it with a rev limiting rotor from a 930 (7,000 rpm as the original 6,800 rpm rotors are hard to find here in the US for reasonable $).

Similar experience here...had my Euro SC out at the track yesterday and was easily revving above 7000 rpm. Datalogger shows 7200. Previous owner must have put a non-rev limiting rotor on it. Which 930 one did you use? I'm assuming the '76-85 was the rev limiting one...

'76-'85 930-602-901-01-M14
'86-'89 930-602-902-00-M14

[SpeedracerIndy]

Originally Posted by jpinkert

Similar experience here...had my Euro SC out at the track yesterday and was easily revving above 7000 rpm. Datalogger shows 7200. Previous owner must have put a non-rev limiting rotor on it. Which 930 one did you use? I'm assuming the '76-85 was the rev limiting one...

'76-'85 930-602-901-01-M14
'86-'89 930-602-902-00-M14

930-602-901-01 is for the turbo through 85, and it works fine. That is the one I have in my engine currently. The only issue with it, is the cut out is at 7,000 rpm, which is 200 rpm higher than the correct rotor. Euro SCs were limited to 6800 rpm as already stated by Bill above.

930-602-901-02 is the correct rotor for the 930/10 motor and you can order it on Pelican, but it's a special order part and is quite a bit more expensive (like double the price).