ErnestSw

The difference is subtle and only comes into play when the cars are driven hard. The GT builds right up to the redline at a fairly constant rate and the S4 starts to fall off around 5500 RPM IIRC. In a drag race, ALL things being equal, I imagine that the GT might reach the top end first. In my humble opinion the main diference is in rarity, bragging rights, and perception.
*********************************************************PUT MARK ANDERSON IN A STOCK OB AND MOST OF US IN A GT AND MARK WOULD BLOW US ALL AWAY!
*********************************************************

Vilhuer

As interesting as dyno charts are they rarely show exact same curve as nice and clean factory documentation curves. Factory says GT should have 430 Nm (316.9 lbft) @ 4100 rpm. If they didn't when they left from factory Porsche commited fraud by saying they did.

I believe almost all '90 MY and newer models got slightly larger GT intake. Some still got smaller earlier version but when old stock ran out only GT style was cast and used. Factory didn't order new casting mould just to make GT version side by side with S4 version.

Late S4 heads seem to have small machining done to small area in channel next to intake mounting point. Can't remember this being in earlier heads. Maybe it has something to do with slightly larger intake channels.

All '90-95 928 have this.

heinrich

I watched Jim Bailey do this very thing as I followed his very brown ob up a hill in Shane's power-monster 86.5 Helmut.

Gretch

Eaaaaaaasy Cheeta.............. Just tweaking you a bit...... seems I hit a nerve.

Ispeed

I think a well sorted car will be the better of the two, regardless of being GT or S4. After driving back 900 miles from SITM alternating between my S4 and Ernest's '91 GT, my car felt stronger. Mine has been gone all through and it feels very good. My friend Chris has a low mile '90 GT that also doesn't feel as strong as my S4, but that car has not had much maintenance yet...low miles.

The GT is rarer and much more collectable, but I wouldn't want to do much highway cruising with the 2.73 box.

ErnestSw

Perception is a strange thing. I doubt your S4 could put down 310HP at the rear wheels. I'm sure it feels smoother and takes less effort to go fast.

ew928

Feel is nice. RMB makes a 928 feel so much faster.
So anyone got 30-80mph pulls, 60-100mph pulls in S4 5-speed vs GT?

Mark A. in a Ford Fiesta might be hard to catch in my slowly driven S4.

No ossifer. I didn't mean to be speeding. But I had to make a point for the crowd on Rennlist . . .

Ernest (NYC)

heinrich

<chuckle>

Marine Blue

Some good facts and a few interesting opinions!

The reality is that H is asking the exact differences and it appears there are some differences in the engine tolerances, shocks, gearing, wheels, shifter length and the digital dash. The biggest difference is the quantity of cars produced.

I think I would agree with Carl on this one. Consider that these cars are all nearly 20 years old and all will need some maintenance to get the back to factory spec. So if you take an S4 and add some sport shocks such as Bilstien or Koni's and go through the engine and vacuum system, some new wheels and a short shift kit you're essentially 15 - 20Hp shy of the GT and no digital dash. The difference in price for the modified S4 5spd vs the GT similar mileage is huge.

So it really comes down to this, if you want the car that will hold it's value because of limited quantities then go for the GT. If you want 95% of the package and some extra money to spend on updgrades and updating you get an S4 5spd.

I'm very happy with my shark, great car, reliable and fun. If I had some extra $$ I don't think I would upgrade to a GT or GTS, I would rather buy a second Porsche instead.

heinrich

Thank you Afshin. Gretch I know you were yanking my chain ... but it disappoints me that you didn't just add your own actual view on the value-add of a GT. That's what I'm after.

worf928

Didn't we figure out a while ago that the '89 S4 5-speed is actually a rarer car than the '89 GT? Or was I dreaming.

[obnoxious announcer voice]

Ladies. Gentleman. Kiddies. It time for the biggest baddest show this side of a hurricane. It's the Showdown at the OK Dynojet Corral. S4s versus GTs.

Get your tickets NOOOOOOOOOOOOOWWWWWWWWW.

[/obnoxious announcer voice]

UKKid35

S4 is 2.64 in Europe (or RoW)

Also, Manual S4's (and Auto's of the same vintage) have the weaker heads that are prone to cracking

worf928

What the Hell. I'll throw $0.928 cents in too.

Carl's S4 is one of the strongest stock 928s I've driven. But, everything under the hood is new. It's very easy for a 928 to be down 5% - 15% on power. Aging MAS/ Old plugs. Dirty injectors. Carbon buildup. Ratty plug wires. Shredded coil ground wires. Intake leaks. Cam timing off a tooth thanks to the previous technician's t-belt job. If you haven't gone through the motor in the last 5+ years chances are you're missing some power.

A healthy stock GT should put down 290+ rwhp in fourth gear on a Dynojet. My bone stock 91 ran 294 in 1999 and 286 in 2002. The 2002 run was in 3rd gear, not 4th. And 30k+ miles later. I figure the 3rd gear run ate a few horsepower and general deterioration of 5 more years of driving ate the rest. My '91's now due for new rubber and electrical bits under the hood. I expect to be closer to 300 rwhp when the next dyno day comes around.

S4s feel a bit slow compared to GTs around town. But, you do notice the little bit of extra low-end torque when you're stuck in stop-and-go traffic. The S4s are less of a chore to drive slow. The GT requires more concentration on left-foot right-foot coordination when in stop-and-go situations.

GTs feel quicker because of the gearing. You're usually turning more revs in a GT at any speed and it feels like the car's ready to pounce on anything. In the S4 you feel like you need to down-shift. Because you're rowing the GT's box more and because the revs are higher, the GT feels more involving than the S4. The GT also feels a bit more willing, able, and happy to turn at 5k or 6k rpm than the S4s.

The GT cams when coupled with an RMB have a fabulous sound. The S4 with small resonators and RMB is close, but the GT's better.

One other thing: As of '91 the shifter **** is shorter and fatter than in previous 5-speeds (S4s or GTs.) This very simple and seemingly surface-only change really improves the overall impression of the 'sportiness' of rowing the box. When I got my '89 GT with the 'old' style 'stalk' shifter my first thought was 'yuck!' Add an after-market short-stalk with the 'fat' shifter and shifts become an almost push-button affair rather than the mile-long-throw affair with the S4's (and 89-90 GT's) 'stalk' shifter.

I've convinved a few folks to pony-up for a fat shifter (either the pricey Porsche part or a knock-off by AGLA www.aglausa.com) and they have all given me a big

mark kibort

flappy looks like it is not working on the GT here.

as was said, most of the difference is in the higher redlinie and the different cam

mk

Stan.Shaw@Excell.Net

I have never driven a GT and only drove my 89 S4 5 speed about 3 miles, but if anyone wants to trade an 89 GT for an 89 S4 5 speed (under going maintenance), please let me know