heinrich

Please note this discussion is *****NOT***** a manual vs automatic discussion. I am interested in getting clarity on why exactly the GT is said to be so much better than the S4 5-speed. I don't see any real advantages. Remember that shocks/springs; chips; tailpipe are all items that would normally already have been equalised by an attentive owner. And '89 S4 5-speeds have aggressive final drive gearing also. Why do YOU say the GT is more desirable than an S4 5-speed?

SwayBar

For stock-block NA 928's, the GT's have dyno'd the highest, 330+ rwhp, whereas strong S4's are 290+ rwhp. That's a BIG difference in horsepower, clearly in the GT's favor.

atb

Its all in perception. In stock configuration, I think the factory HP spec giving the GT a 10 hp nod attacts a lot of attention. Funny that Porsche doesn't mention the 10ft. lb nod to the S4. I realize that there is a list of improvement items in the GT vs. the S4, but going down the road it comes down to whether you're more into rowing a gear box or torquing through the gears. Personally, I'd prefer the S4 over the GT. Get one with sport suspension, and your home.

fabric

Doesn't the S4 have a 2.54 (or something) vs the GT's 2.72? More aggressive than the earlier S4's, not sure how much of a difference on the road it would make. The low gearing of the earliers S4's has them running lower revs on the highway, but probably not a huge deal in the US, and not sure how much it actually affects MPG.

Do we have a definitive answer on the resonators? A consensus seems to be forming around X, S4 resonators, and RMB. Followed by X, GT resonators and rear muffler. I suppose that's a personal preference, but depending on what you want, and what it has, you'll not have to spend as much $$/time swapping things around.

I prefer flat dishes, so I have to vote for the S4. I know there are a bunch of other little things, but I suspect if I were choosing between 2, color combo would be the actual deciding factor.

Vilhuer

If '88-89 CS and UK only '88 SE are left out in my view there are really four separate manual gearbox models in '87-91 MY's, '87-88 S4, '89 S4, '89 GT and '90-91 GT. In US big deal seem to be about short gearing. I would be much more excited about GT cams, digital dash and LSD. Its true that GT gearbox is stronger but S4 box is strong enough for hp close to stock engine makes. None of the versions are perfect. '89 GT is closest if GTS is not counted in and that shows in price also.

Adam, GT has exact same TQ as S4, 430 Nm in both. Peak is just much higher up, 4100 vs 3000 rpm. Difference isn't really that large as GT has 420 Nm @ 3000 and S4 420 Nm @ 4100 IIRR.

johnf95111

Senior H,

I noticed your response to my post in the thread where this came up. You mention all the upgrades. For collectors or for some one who wants a car that is unique in the 928 family, the '89GT stands out. I have the original sport suspension in my GT. It still handles the road like it's on rails. I don't have a modified brain, just the stock GT version to handle the requirements of the tune and different cams. This along with the different gearing, my relatively stock GT feels very lively. I like my 16" forged Fusch rims, I may bump up to 17" to reduce the side wall flex, but there is a penalty in the un-sprung weight; unless you pay $$$$. The only mods I have to the exhaust is an RMB. Paired with the stock GT resonators, the sound is wonderful. I will be adding one of Louie's X pipes when I redo the complete exhaust with headers. I'll probably have to put my stock GT rear muffler back on due to elevated sound when I romp on the loud pedal.

All in all, the GT as its sporting predecessors did, like the CS, was built to stand apart from the S4. And in its day, it did. Sure, there are bolt-ons that can give an S4 the same or better handling and performance, but the GT is unique and holds a place of it's own in the 928 family tree.

Cheers,

Bill Ball

Ah, heck!

cfc928gt

Heinrich,

If you're refering to the '89 S4 5 spd on ebay...just buy it!

One thing no one has mentioned is the crimped fenders found on GTs that allow the wheels to be moved further out.

As far as gearing goes, I'd personally perfer the slightly lower gearing of the '89 S4 5 spd vs my '89 GT. I don't like driving highway speeds at 3000 rpm.

As others have said, you'll love the digital dash and I prefer the backlit gauges as well.

Ed MD

After '88, both the GT and the S4's have the GT resonators (look below, I have a set that I just took off the 88)), in regards to the difference...check with Carl (Boston) as he elected to get a 5-spd S4 instead of a GT for his driving needs...he consulted DR in regards to it. Ed M

laufenOutLoud

Just for a second I imagined in my mind's eye Porsche rolling out a V8 tourer like the 928 in 1997 instead of 1977. Man, the difference in electrical reliability and computer innards! But would it *feel* the same (with most of the focus on engine mechanics and driveability)? And would we be having these conversations in 2027 instead of 2007?

atb

Erkka wrote:

I haven't found that to be the case with our local cars, it seems that S4's consistently out torque the GTs down low, and then the GTs then open up above 5500K

Here's an example of what I've seen as typical with our group's cars. (maybe all the rain plays a factor? ):
89 S4 (Red/Rose) vs. 91 GT (Violet/Black):

atb

Here's another. Both S4's (here and above) are 5 speeds by the way.
I couldn't get these graphs to overlay using RPM as the horizontal axis, so I had to use MPH. But you still get the idea. Looks like the S4 may have had some flappy issues, but you still see the same pattern, lots of grunt down low in the first peak for the S4, and then the GT taking over in HP in the higher revs.
I don't want to get into dynowars here , I've just noticed this enough to call it a pattern. Anyone else notice similar power delivery differences between the S4/GT? Based on factory info, the first peaks shoud be the same with the GT getting more up top.

S4 blue vs. GT red:

johnf95111

Something is a bit off. My relativly stock '89GT dyno'd at ~290rhp peak last Devek Days.

Cheers,

PorKen

Adam,

So you could, in theory, make a S4 almost a GT by advancing the valve timing? Or vicee versee?

atb

johnf wrote:

Hi John, that was kind of the basis for my "dyno wars" comment. In each graph, both cars were dyno'd on the same dyno on the same day. So I'm looking at the basic shape of the dyno curve, not the exact measured output.

Porken wrote:
Nope. Net #'s will still be the same.