ROW vs. US CIS

[carl74344]

I have a 1982 911sc. i was thinking if the ROW 911 has a simpler CIS system why can i not change to the ROW system? what would be the good and bad about that?..............thanks carl.........................

[timmy2]

I don't know if it is compatible as I believe the ROW cars continued to have larger porting than the US versions. May make adjusting it a real bear.

[carl74344]

is the only difference the pollution? if it has less stuff it might be better to tune.
thanks carl

[Josh D]

'80-'83 US are small intake port heads
'78-'83 RoW are large intake port heads
'78-'79 US are large intake port heads

You would have to open up the ports on your heads or switch to early US or any RoW head to use RoW CIS

[carl74344]

what would be the gain? would it be worth it? carl

[Nickshu]

In 80-83 ROW cars also had higher compression pistons. One reason for the larger intake and different fuel distributors.

[DanielDudley]

I had an 81 euro, and I currently own a 78 with Euro pistons and cylinders and a euro fuel distributor. They go together. I am certainly no expert, but you will get good results from converting to SSI heat exchangers and a free flow exhaust. If you ever change over the rest of the engine, you will need those anyway.

[Josh D]

In 80-83 ROW cars also had higher compression pistons. One reason for the larger intake and different fuel distributors.

So did US cars.
'80-'83 US 9.3:1
'80 RoW 8.6:1
'81-'83 RoW 9.8:1

If you were building a 3.0 CIS motor, you'd want to mimic the 204 hp 930/10 RoW (big port heads, 9.8:1 CR, RoW CIS and ignition distributor)

[Nickshu]

Originally Posted by Josh D

So did US cars.

Still don't understand your statement...

An 82ROW has higher compression pistons than a 82US. 9.8 vs 9.3

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[Reiver]

Think he meant that the earlier US SC's had a lower comp ratio than the later SC's that went to 9.3.
You could prob use the ROW CIS, I don't think it is 'simpler' it just delivers more fuel due to the comp ratio need and will make you run richer as lean and HC don't mix. Bang.

[BayPawn]

I am in the process of doing this right now. I started with a 82SC US. I have added 9.5cr Mahle 98mm P/C, I had the heads ported to the larger intakes with dual plugged heads, a Webbs stainless airbox, and the rest of the intake from a 79SC large port. I have taken forever to do this because of the "while you're in there" issues such as rebuilding the fuel distributor and warm up regulator(making it adjustable of course). I'm going to have the wiring harness rebuilt because A. It looks like crap B. I am planning on using an Electromotive dual plug ignition system and I need to find out which wires from the harness that I can safely eliminate. If anyone can tell me this, Iam open to suggestions. Phil

[Josh D]

Originally Posted by Nickshu

Still don't understand your statement...

An 82ROW has higher compression pistons than a 82US. 9.8 vs 9.3

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In 1980, much like 1975 and every succesive year after, the CAFE and emission standards where rising quickly in US. In order to meet those standards for MY 1980 and avoid gas gussler tax in US, Porsche raised compression ratio and increased port velocity at lower engine speeds by making the intake ports and runners smaller. There was also the change in ignition curve and the addition of the O2 sensor with a lean fuel curve. All of this was done to improve fuel economy and lower emission while maintaining performance at the lower speed limits in the US. The changes effectively created higher cylinder pressure at lower engine speeds creating a very responsive engine with a nice flat torque curve at lower engine speeds. This was a common formula for a lot of manufacturers selling cars in the US (ever heard of BMW's ETA engines?).
In Europe (and everywhere else) the standards were different as well has speed limits in some areas so they had more free reign to build and tune to those conditions.
Even with lower compression than the US version, the '80 RoW engine with bigger ports, advanced cam timing, richer fuel curve, and more ignition timing still generates more torque than the '80 US. It's also a livelier engine at higher revs that will respond better to mods (ie SSI's). The downside is that it gets noticeably worse fuel economy and pollutes.
Back to the OP, a US 9.3:1 CR engine with a RoW CIS and distrubuter (or recurved stock dizzy) would make for a great engine, much like the 930/10 204 hp engine. However, to make it work, you have to modify the stock heads or use heads that already have the big ports.

[carl74344]

so i guess the best thing to do is to make it all like new. keep my 1982 911sc the best by keeping it factory. make sure everything is set right. enjoy driving it. keep it clean, and have fun ....... thanks everyone.....carl