DeWolf

Hi All,

I was of the opinion through various sources including Porsche Cars Australia that the 85 4.7 cars that Oz got were identical in spec to the Euro cars, power wise. Is this correct?

Cheers

The Forgotten On

They have reduced compression to deal with then's poorer quality gasoline. The make about 280hp vs the euros' 300-310.

Otherwise they are identical.

DeWolf

That's what I was told once but my factory trained 928 mechanic reckons it isn't true. The only reason they produced less HP was because we didn't have a premium octane fuel at the time. I'd like to see actual factory compression numbers if they are about.

ANF

All of the previous Aus versions were listed as the same HP as the euro ones, the 85 the only listed as being lower, 275 hp. The 86 5.0 S3 is the same, with a lower output.... (same as US)

Not sure how trusted or true Wikipedia is...
"Special two-valve 4.7 L engine (9.3:1 c/r) option M151 for Australia. Compression change was done with different shape piston tops. Coupled only with automatic transmission. Engine number is same M28/22 as the high-compression 2-valve engines."

Vilhuer

This is based on PET having different part numbers for pistons and certain factory documents which show piston pictures. If people have found these from engines they haven't made connection about them being special enough to take pictures etc. One way to check without opening engine is to check what pistons look like from spark plug holes. Another is to check compression. There should be visible difference in compression measurement but this would need several comparisons to higher cr engine results.

hwyengr

Not quite. The US 86 5.0 is 10:1 and has 215kw/292PS/288hp. The AUS 86 is 9.3:1 and has 212kw/288PS/284hp.

Mrmerlin

I thought they used thicker head gaskets to change the CR, this is much easier to do than making specific engines with special pistons ,
I have not seen any different piston pictures other than the lower 10.0 to 1 for the 83/84
to the 85 10.4 to 1 16V Euro engines
Does anyone have any pictures?
I had 2 85 Euro engines apart and they both had the same pistons and one was from Swiss market with auto trans.

The HG from that car seemed to be thicker that the new part that went on.
Thus the engine was returned to its full HP potential it was a strong running engine when I was done with it and the same can be said for the 5 speed 85 Euro engine I built it was strong