Just got my 1990 348TS gets hairy over 100mph!

Totally normal actually, you may want to add the front air splitter, it really helps stabilize the front end at high speed.
Also, congrats!! And welcome to the Brotherhood!!

 

Don't forget to keep the original boot weight:

- ToolKit
- Spare Wheel
- Carcover
- Document wallets

 

Yup what Steve said, and welcome Bro

 

I have to take your world for it... on the early 348's that is...

They were all updated over here by the dealership network.

Nevertheless, my 125mph run just felt rock solid. I even jerked the steering a bit to tease, and nothing...

I guess the GTS mods really do make a diference...

 

Isn't that why spacers were recommended and later factory installed on the SS? Also, my SS was a bit loose near 125 until I had a pro look at the suspension. Turned out the setup was wrong.

 

What specific tires are you using and what are your tire pressures, front and rear?

 

Do you know if the suspension bushes were ever changed/refreshed? I once read on here (can't remember which thread) that handling issues described in a particular 348 turned out to be that it was running on suspension bushes that were about 18 years old. Once these were changed for new bushes, the handling issues disappeared.

Sorry, I know that's very vague... hopefully it's enough to jog someone's memory and find the original thread.

All the best,
Andrew.

 

I can say that putting 25mm spacers on the rear of my 1989 helped higher speed stability. I wuld guess the splitter would also help, but try adjusting the tire pressures first, that made the biggest difference for me. I ran about 32 psi in the rear and 34 in the front on Pirelli P Zeros. If the tires are over 6 years old I would change them out to some Yokohamas or maybe Michelins if you have the budget for it. My Pirellis were terrible about tramlining and made the car feel skittish at speedalthough I only felt threatened above about 120 or so.

BT

 

Proper alignment and suspension settings + quality tires should fix your problem. I have a 1990 TS that is rock solid to 135 MPH, which is as fast as I have driven it. The car was very difficult to drive when purchased... tires were worn out and settings all wrong. This isn't an easy job so be sure to trust your work to a shop with experience in setting up 348's. My shop took 4 hours to get things right.

I also have 25mm rear spacers, however they were on the car so cannot say if they make any difference or not.

348's are more demanding to drive at all speeds. Compared to a 308/328, they are a completely different ride.

 

Congrats on your purchase, and welcome to the forum!

I've had my 348 spider above 100 mph several times; once at -or just slightly above- 120, and it did not feel squirrely at that speed. That particular straight stretch just wasn't long enough. The suspension setup (to my knowledge) and wheels are stock.

 

I am surprised that anyone said it was 'normal' to feel light in the front at only 100 mph. I say only, because relative to what this car is capable of, 100 mph is not much. I would check what kind of tires you have (high performance -vs- cheapos and that they are the proper size), air pressure when cold, alignment settings, suspension (look for worn shocks or other parts that may be worn), and if all aero parts are in place and secure. The reason I say that is that the 348 should be very stable at that speed. I remember having our 348ts up to about 170 mph on a drive home and it was very stable even at that speed. Also, what kind of road surface are you on? That car should feel very stable at 100 mph on the highway.

 

Yes, it helps! Needs to stick out about 1.5" to move enough air over the car.

 

+1

I recently drove a 997 and had new stat-of-the-art Yokohamas on the rear.

The car was just undrivable between 100 and 125mph, and far from trying to go above that!!!

With OEM tires, it feels rock solid up to 170mph.

Incredible!!!!

 

With my GTS, I just drove it a few miles before putting it on the lift for the big one.

Nevertheless I pushed it thru traffic, went up to 125mph, braked hard, jerked the steering... and I must confess that even with standard setup (even 16 year old Expedias) I did not feel any odd reaction... everything was spot on...

But we also have knowledge thar early 89's and 90's were called back by dealers to change the complete front end, under some brand notice.

 

alignment....

most of these cars have never had one since the day they were new..

 

nothing worn out or broken
chassis rake
alignment...go to a race shop...you will be glad you did...forget everyone else
tire pressure

When I raced my 91 348ts I spent most of my time over 120 and it was rock steady. There are many tricks to getting it right. Getting it wrong pays big penalties because the 348 chassis is very tunable like a real racecar. That is it's blessing if you like to drive fast and it's curse if you are mostly a waxer/polisher depending on the expertise (or lack thereof) of others.

 

This is from my 355...super stable. The one at 180 is too blurry. My 348 was always stable as well. Frequently did well over 150 with her!
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Sorry for the blur, it was taken on a i-phone video. Speedo at 180 tach at 8500, GPS registered 176 mph.
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Jeff.

No evidence

Hope your well.

Craig

 

Great 'closed course track' pics Jeff !!! In my experience the 355 is very stable at high speeds!

 

All pics are from a "track" of course