Don '85S3

Thom -

Per 928S4vr <a href="http://www.928s4vr.com/928s4003.htm" target="_blank">http://www.928s4vr.com/928s4003.htm</a> the S3 designates the release of the 32V motor ('85 and '86 models), S4 in '87. Who's correct?

Thom1

Hi Don,

Ah, there’s the rub! Like you, I would rely on Phil’s site more than most. Where does he define the S2 series? Why does he not call the 1986 model an S3? Why is the 1986.5 model omitted? Members of the PCA are not normally Porsche employees. A book written by the PCA is not Porsche official documentation. Phil quotes: “The Porsche Family Tree, published by the PCA. The book may or may not be quoted correctly. Most PCA guys know very little about the water-cooled types. My local Porsche dealership employees are mostly less knowledgeable than me about 928s. Who knows?

My official “Porsche Technical Specifications” publication: “Porsche Models Dimensions Tolerances, 928 S Modell 85, 86, 928 S4 Modell 87, 88, 89, 1st Edition, Stand as of 10/1/1989” omits definition of S2 or S3.

Can somebody call Stuttgart, and get the opinion of the engineers there?
<img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" />

Don '85S3

Thom -

I have heard that the different "S" series were based primarily on engines changes, as follows:

S1 '81, '82 4.5L 219HP
S2 '83, '84 4.7L 234HP
S3 '85, '86 5.0L 288HP
S4 '87 - GT 5.0L 316HP

Anyone have the definitive answer???

SHRKBIT

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by urnotthesameina928:
<strong>...hence the very strong pull after 4k rpm maybe??</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">The increased pull of S4 and later engines above 4k rpm is almost surely due to the intake resonance valve ("flappy" ) changing position and a change in timing. It's not uncommon for an old "flappy" to fail, and it's a very discernable difference between having a functional flappy or not.

Curt

Vilhuer

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Thom:
<strong>
S4 CS 88 EURO 326HP (GT Camshafts, minus 220 lbs. of accessories, adds 675rpms to rev limit)
S4 SE 88 UK (CS with accessories)
GT 89-91 EURO&USA 326HP
</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">To my understanding there is three different cam sets for Club Sport and GT engines
S4 CS and S4 SE EURO officially 326HP but maybe closer to GTS numbers
GT 89 EURO&USA 326HP officially 326HP but maybe little more than later GT's
GT 90-91 EURO&USA 326HP

Regards,

Erkka
Helsinki, Finland
1992 GTS 5sp needing a lot of work
22L MX
C00 139 327 340 650 935 980

Big Dave

Rufus:

I can vouch for the noticeable increase in power using aftermarket chips in an '85. I haven't been on a dyno, but other 928 owners that have been in my car since the chips were installed also say there's a big difference.

With my "x" crossover cat bypass and the chips, I was chirping the tires (AUTO trans) when going from 1st to 2nd gears as well as 2nd to 3rd at the drag strip last month. THAT never happened before, and I've got 255/40/17s on the rear wheels with lots of tread left.

You ought to check with Dozman (about chips. He may have a set he's willing to sell!