words by pablo deferrari

the US-spec 1983-1984 928S...3 years too late.
three years...it took one of the richest countries in the world to enjoy a beast of a 928 Europeans have been thrashing around since 1980...what the hell am I on about?

the 928S.
I won't bore our international readers with a "how dare Porsche not give us the best first," and "why should we, a privileged country every manufacturer aspires to sell their tastiest bits to," speech on how we got cheated...that would mean getting into politics, regulations, and all of that rubbish; and I hate that.

what I will do, however, is educate you on what we missed out on, what we got instead, and maybe...just maybe, explain why things went down that way.

let's start with the differences in the non-S models. in 1980, the Euro/ROW engine numbers were M28.09 for the manual gearbox and the M28.10 for the automatic. displacement was 4474cc (4.5) with 10:1 compression ratio putting out 240bhp (DIN) @ 5250RPM and 271 ft-lbs of torque @ 3600RPM. these lumps still used the mighty CIS K-Jetronic fuel system found on the '78-'79 models.

the US engines were M28.15 for the manual, and M28.16 for the automatic with the same displacement but with a lower compression ratio of 9.0:1 squeezing out 231bhp (DIN) @ 5500RPM and 265 ft-lbs of torque @ 4000RPM. but the fuel system was changed to the AFC (air flow controlled) L-Jetronic, a more flexible and economical set-up.

for the sake of argument, the Japanese values are the same save for the engine numbers; M28.17 for the manual and M28.18 for the slushbox...but we're not concerned with that version here.

based on the left-brain sleep inducing figures above, there was a difference of 9HP...big deal, right? well, no, not to the right side of your brain. you see, that difference was mainly attributed to the emissions set-up of US versions that featured 3-way catalytic converters, O2 sensors, and secondary air injection. the one-two punch came with a lower compression ratio, ignition timing set at 23° before TDC at 3000RPM without vacuum (Euro/ROW was set at 28° TDC, same RPM, no vacuum).
the 930's arch rival, the 300hp 1980 928S
you could also factor in the spark plug differences tailored to both versions, the Euro/ROW used Bosch W8D while the US mill used Bosch WR8DS. the interesting thing about the plugs was that the US version had a suppression resistor (the "R" in the equation) and a silver electrode (the "S") used for a high performance applications by igniting the air/fuel more easily for optimal power output. 

this might explain why the US version needed this fine silver wire due to our fuel quality and lower compression...we needed all the help we could get. the heat value was the same at 8; the "W" and the "D" denotes the thread (14mm diameter) and thread reach (3/4" extended tip) respectively. 

I've digressed the hell out of things with the plugs, but the differences are interesting and you may have just learned something new.

right, now that we've gotten the non-S versions out of the way..let's talk about the S we didn't get in 1980.
'83-'84 US-spec 928S from the rear.
the bumperettes and absence of a rear fog lamp are give-aways of a 928 with a US passport.
the 1980 inter-cooled 3.3 liter 930 put out the same horsepower as the '80 928S, but had a 318 ft-lbs of torque (35 more than the 928), weighed in at 2866 lbs (1210 lbs lighter), and had a top speed of 161 mph (6 mph faster)
any Porsche enthusiast worth his or her salt knows that the “S” in any of Zuffenhausen’s models mean “Super.” and that’s exactly what they did with 928.

what they, our Birkenstock and black sock wearing comrades, got was an engine (M28.11 manual and M28.12 automatic) bumped up in size from 4,474cc to 4,664cc by increasing the bores from 95 to 97mm, hotter camshafts, a unique distributor, a freer flowing exhaust system with a continuous twin pipe design to the rear muffler, new Mahle pistons for a 10.0:1 compression ratio and K-Jetronic fuel system running on premium grade gas. the result? a healthy 300bhp (DIN) @ 5900RPM and 283.4 ft-lbs of torque @ 4500RPM.

Dr. Fuhrmann must have been tickled pink since the new 928S had the same horsepower as the 1980 911 Turbo, even though it yielded the same results with 1,400ccs less at 3.3 liters and more torque coupled with lighter weight…the 930, for the sake of politics, would not and could not play second fiddle to the 928.

we, as far as 928s were concerned, were left drooling...don't worry, so were the 930 enthusiasts. wanna know why? Dr. Fuhrmann got it so in his head that the 928 would replace the noisy, aging 6-cylinder air sucker, that he cut back spending money on re-regulating the 930 for the US/Japan market in 1980...that's why the Turbo was never to be seen again on our shores after 1979.

the bright side of the equation was that the 928 was the most powerful Porsche available in the US from that moment on...the unblown 911SC's horsepower was no match for the high revving V8, and even when they did bring the Turbo back in '86, the 928 remained King...Dr. Fuhrmann got his way in the end..sort of.

so you see, the whole problem revolved around emissions, and that’s why we got screwed.

when we look at the CO levels in percentages of what was acceptable to our government, we can see why; .6%+/- .2% was what the US 928 was putting out…the Euro and ROW version's CO content hovered between 1.5-2.5%, a bit too rich for our noses. 

take a moment to consider these figures and you can see why it would’ve been pointless and expensive for Porsche to choke the 1980 S in order to comply with our stringent standards...this is also precisely why the grey-market thrived.
the heart of the US-spec S...the fuel damper to the left of the distributor tells us that this one has the L-Jetronic.
view of the cockpit...
and of the rear seats.
finally, as 1983 rolled in, we saw the introduction of the S in the US with the proper 4.7 liter 16V V8. 

interestingly, Porsche offered a “Competition Group” package for the US from MY1981 through MY1982 to whet our appetite until the S was officially launched on our shores in 1982. What we got in with this package were the S front/rear spoilers, Recaro seats, sport springs, Bilstein shocks, limited slip differential (you read that one right), and the 16” Flat Disc wheels…essentially all the goodies of the Euro S but with the old 4.5 liter lump. 

how is all of this relevant? well, because the 1983 S marks a significant evolution for 928s destined for the USA that gave us not only a larger engine and all of the goods from the “Competition Group,” but also a new standard 4-speed automatic transmission (US/Japan only, manual was an option), hydraulic motor mounts, and hydraulically dampened belt tensioner with the front and rear spoilers becoming standard. The 4.7 liter M28.19 (manual) and M28.20 (auto) engine produced 242bhp (DIN), that’s 11 more horsepower than its predecessor while doing it at a lower 5250RPM but packing slightly less torque at 263 ft-lbs at 4000RPM. 

compression was bumped to 9.3:1, and like the Euro S, the bore was increased to 97mm while the stroke remained at 78.9mm. the same L-Jetronic AFC(Air Flow Controlled) fuel injection system offered since MY1980 in the US was used providing a bit more flexibility and economy than the K-Jetronic CIS (Continuous Injection System) unit used up until MY1979 in the US. not only was this engine more powerful, but also more flexible.
so what more have we got? how about better highway gas mileage at 27mpg thanks to revised gearing and a final drive ratio dropped from 2.75:1 to 2.27:1(manual trans), larger brakes stopping it from 70 to naught in an impressive 188 feet, lower drag coefficient from an embarrassing 0.41 to a respectable 0.38 with the help of front and rear spoilers…all part of the S package. 

the icing on the proverbial cake is a top speed of 146 mph, 0-60 in 6.2 seconds, and a quarter-mile in 14.7 seconds @ 94 mph. Porsche boldly claimed it "the fastest street legal production car sold in the US.”

I'll end it here, with a little more salt in the wound, because quite frankly...my head is beginning to ache.


the 1983 Euro/ROW version 928S had the same engine since 1980...the M28.11 for the manual and M28.12 for the automatic...but in 1984, Porsche upped the ante for the Euro/ROW version...the S got a newly revised engine, the M28.21 (manual) and M28.22 (automatic) boasting 10.4:1 compression, and 310hp (DIN), the LH-Jetronic fuel system with overrun cut-off, and electronic ignition...oh, and it got an impressive 27mpg at a steady 75mph.

what did the US get in 1984? the same 928S we were offered in 1983...but wait until 1985; all would be forgiven with 32 valves.



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