How do you ID a GT vs S4 5 spd?
 

What do you need to look at or check to be sure a 928 is a GT and not a S4 5 spd?

Tranny code.

From what I understand, first year GT's in 1989 had option code 639, in 1990 most 5 speeds and ALL 1991 5 speeds are GT's. It is the 1990 MY that can be confusing.

Here is a good explanation:

http://www.928s4vr.com/928s4005.htm

Three things:

1. Engine type code M28/47 on the block just below the cooling bridge (my 5-spd S4 is M28/41 )
2. Transmission type code G28/55 (5spd S4 is G28/12 on my car, I think US cars had G28/13 with the 2.2 final drive?)
3. Option code 639 on the sticker (M639 is for GT).

Also, GT's were only produced from Feb '89, so the manuf. date on the door jam will help identify an S4 relatively quickly.

Lastly, some 5-spd S4's have limited slip dif - option code 220, or 6th digit of "2" on the transaxle number. e.g. on mine "G28/12 1K" - the 1 indicates no LSD.

89 is the only year where both a S4 and GT can ncome with a 5spd. All S4 models after 89 are auotomatics. Wouldn't the engine code be different in addition to the tranny code? A 89 S4 has a 2.64 ratio and a GT has 2.72.

all you have to do is look at the registry http://www.928registry.org/
I've notated all the GTs by serial #

Thanks, looks like in person the engine ID is the quick way, if all I get is the VIN there is no magic digit to check, just check the registry.

First of all, kudos goes out to the Rixter for putting together such a precise and definitive list of all '89 GT's, plus other years as well.

Now I don't know if this has ever been mentioned before or not, but all '89 GT's also have option code 046 in addition to 639. I've owned enough '89 GT's to know this is indeed the case with all '89 GT's. For whatever reason, Porsche technically gave two definitive option codes to the '89 GT. I can find no website or otherwise to give me any different description of option code 046, so I'll just have to assume it also denotes "GT". And you'll only find option code 046 on '89 GT's. Never on any year before, never on any after.......

Porsche AG; those crazy guys! ;)

Todd SmileWavy

If you've ever been to a (German car) factory...you'd know how literally true this is.


--Russ

It is always worth considering that a genuine GT could have a replacement motor or tranny.

My 89 ''GT'' was authenticated by a Porsche dealer. It was an S4. I found out by running the numbers with David Lloyd.

The good side to there being a split in the '89 model year is the occassional mis-informed seller selling his/her '89 GT as just an S4. How do I know this? I've been the lucky recipient of such ignorance 5 times now! Suweeeeet! :D

Low Miler SmileWavy

No, All 1990 and 1991 5 speeds were GT. 1989 is the split year.

^^^^That's absolutely correct. But that doesn't dismiss the occassional seller of a '90 GT being just as mis-informed as an owner of an '89 GT selling his/her car as just an S4. Such is the case with my most recent aquisition last week. A '90 GT with 70K being sold by it's original owner (though the car was purchased for him as a gift from his wife), as just a 1990 928 S4 5 speed. Hey, at $12K, I really felt no need to bore him with the actual facts behind the cars true credentials. Instead, I choose to just pay him in full, quickly, and to then get the H out of there! SmileWavy :D

Todd :)

Owners are often confused.

Especially when buying sight unseen. Worth the trip before handing out the cash.