Red Flash

So, here is maybe a funny question for some of you. But here goes:

We know that the 928 has a very durable motor and even the manual transmission (not to mention the automatic) is very durable, if driven by not the most spirited drivers like me. But, what about the chassis? How many miles do they remain tight?

I explain the background behind my question. I bought my 9-3 convertible in 2003. Its had all its life a stock suspension and been treated rather nicely. It is evident after 150.000 miles that the body is just not as tight as it used to be. This is really an understatement. So much so that although the car looks new still, I'm getting tired of its general softness. And even though the compression is within 5% on all cylinders, I'm thinking on getting rid of it.

My 928 now has Eibach springs and Bilsteins. I am not even sure, if I need this much suspension... What will be the consequences of this sportier suspension on the chassis anyway? What parts on the 928 chassis actually fatigue notably? I guess the people racing 928s might have the best input.

Speedtoys

Seam welding.


Spots get weak..in the older RX7 racers..you raced them until the rear glass panels blew out..then enough spot welds were buttery enough..that it was a lost chassis.

hacker-pschorr

Possibly your SAAB is a wreck repair?

Our 99 9-5 with 150k+ is still solid as a rock, so is my friends 9-3 with over 200k.
My local shop has a customer with 350K on a 900 - original owner.

There is an expression about SAAB's, you never appreciate how solid they are until you crash one.

jcorenman

I think the key word here is "convertible". Metal fatigue is related to metal flexing, and convertibles have a lot less stiffness in general than coupes.

Try this: take a shoe box, tape the lid in place securely, and then try to flex it by twisting the ends in opposite directions. Not much flex, right? Now cut the lid off and repeat the experiment. That's the difference between a coupe and a convertible. (Actually, to be fair, take the lid and tape it to the bottom, that will help a little. They do reinforce the bottom pan for convertibles, which helps a little).

Charley B

Trying to compare a ragtop to a stock 928 for chassis stiffness is utterly worthless.

jon928se

Fixed it for ya.

And to be fair the 9-3 convertible isn't noted for it's chassis stiffness even when compared to other convertibles based on standard saloon cars.

I doubt you'll have any issues with the 928 even with slightly stiffer suspension. The only area I have heard of issues with on aggressively tracked 928s is cracking to the front "chassis" rails.

jpitman2

Some models of SAAB convertibles, where the floor pan was based on an Astra, are well known in UK for the steering loads cracking the firewall/bulkhead, because the loads were not well enough distributed into the body. There is stiffening kit available in UK for this. Not sure if yours fits the year/type, but its worth checking. There was an episode of something about buying cars cheap and doing them up (English show on cable here - Wheeler-Dealers) that covered this in some detail.

Tracked 928s have been known to damage the roll bar fixings when aggressive bars are fitted.

jp 83 Euro S AT 54k

jon928se

SAAB 9000 - based on the MkIII Vauxhall Cavalier body shell, but IIRC the problem wasn't restricted to the convertibles.

NordicSaab

I figured I had no choice but to chime in here

I had a 2001 Saab 9-3 coupe that was modified to 320whp. One thing for sure is that platform is not very rigid (and I had the firmest model, the coupe). There are numerous braces for that car to tie the frame and subframe together because of that problem. NordicSaab(big Saab tuner in SE) has been known to seam weld cars even for modest performance applications. A convertible top would only exacerbate this issue...

I don't think all makes and models are as prone to this issue as the Saab would be. The 6 pt subframe brace from genuinesaab.com makes a world of difference if you would like to firm it back up.

Warning, Saab content:

Red Flash

So, thanks for all the responses. And, Charley, I was not comparing a convertible to a 928. My only intention was to share that from experience, I know that some cars exhibit metal fatigue and to find out what the implications for a 928 are. It sounds like metal fatigue issues are restricted to only tracked cars, or?

Coming back to SAABs, since so many commented. The 9-3 convertible from 2004 on is amazingly rigid! Now, the one I have based on the Astra (mentioned above and pictured by Nordic SAAB) is really a disaster. And no, I bought the car new and it has never been in a wreck!! Only 2 small dings in the body after 150.000 miles that's it!! The 86 900 "classic" on the other hand is built like an anvil. :-)

dr bob

I finally sold my 1980 900 turbo, with 300k on it, for space and tax advantage reasons. It was still solid as a rock even with the massaged engine and suspension, and more than a few serious high-speed trips on it. Amazingly durable chassis. When GM took them and started building them on lesser chassis pieces, Saab moved off my candidate list.

worf928

Mark Anderson might have the best empirical data.

IMO, the progressive Eibachs with Bilsteins (or Koni's) is less jarring that the factory GT suspension.

Speedtoys

How many miles...Im at 254,000..like a rock.

Jim Devine

Just a guess, but if it's a rust free car that hasn't had repaired collision damage, the body will probably last until we go to the nursing home or we run out of money for mechanical parts.

IcemanG17

the 928 body is extremely stiff..... a simple test...jack up one wheel and see how high off the ground it gets before the other side also comes off the ground....

When most street cars become race cars the cage has lots of extra braces to strengthen the chassis....very typical in Mustangs and BMW's....

A street 928 body will outlast just about everything else in the car.....rust is nearly a non issue... in fact I don't think I have ever seen one that was "loose"