924Board.org

[SSen100]

How much vibration and general NVH is normal in a 924S?

The engine seems fine: smooth, performance great.
Tyres/Tracking/Suspension seem fine: just had them checked out (not at a Porsche specialist, admittedly). Recently had new shock aborbers at the front, rear ones 'OK, not great'

What I notice is this:
Car vibrates at idle, but give it gentle revs and it's fine, really smooth.
At speed (50 mph+), car feels OK and I'm comfortable, but the vehicle must be vibrating a lot because the view in the mirrors is really distorted - can't read the number plate of a following car unless it is really close.
Also, rear suspension feels fine except it suddenly thuds on minor road imperfections (of which there are many around here).

Does this sound normal to anyone or is there a problem? I can't tell because I'm new to Porsches and have been spoiled with modern cars!

(What got me thinking was an article in a classic car mag about Merc SLs. This warned you to stay away from an SL that vibrated in a similar way to I've described my 924S above - vibration in an SL was a sign it had a large bump to its chassis)

[garthfan]

Even after replacing the front struts and having the front-end aligned, I notice the exact same thing. Harsh handling over bumpy roads and excessive vibration as seen in the mirrors. I haven't replaced the rear shocks yet, and some folks do indicate that might be a big part of the problem.

But what you describe is exactly what I'm going through with mine.

Anybody???
_________________
1987 924S - Was a daily driver...now it's GONE! *sniff*
1986 944 N/A Guards Red
1996 VW Jetta Grocery-Getter
1995 Saab 900S Winter-Driving-Feeling-of-Security-Vehicle

[welder]

That sounds like motor mounts. I've installed new ones and the engine is silky smooth at all speeds. That mysterous banging in the rear might be rear control arm bushings. From what you describe it happend when the suspension moves up and down. Check those and any rear stabilizer bushings. It might just be a broken bolt. Any issues with the steering while at a stop and moving the front wheels side to side? Have your tires become unbalanced, possibly losing a wheel weight. I still vote for the motor mounts as it happens while moving and at a stop. Grab the valve cover with engine off and try to shake the motor side to side, if you can get plenty of movement it's the dreaded motor mounts. Good luck.
_________________
I have a 78 n\a currently under restoration.

[gohim]

Probably the engine mounts.

Vibration at idle that smooths out as engine speed increases signals bad engine mounts.

The genuine mounts are more expensive, but will work better, and last longer than the generic/aftermarket mounts that are being sold.

Check the exhaust system for interference at extreme suspension movement (over the left cv axle is a possible contact point). Since the rear shocks are not in the best condition, they could be allowing more travel than necessary, and as a result, the cv axle could be making contact with the exhaust on large bumps. The rear muffler could also be sagging down (the joints between the contacting pipes and the rear mufflers often rust off) especially when the muffler has been replaced with an aftermarket part.

[Sleykin]

Hmmm? I guess all things are relative. Mine vibrates more than my 02 exlpoder but less than my 83 Bronco. (Bronco has a bilt 429 and the cam is lumpy) I adjusted the idle (jumpered the plug and adjusted the bypass screw) and that helped kill most of the idle vibration. I don't get any sharp thumps on the road. My tires flatspot overnight and I get a bit of shimmy/vibration for the first 2 miles but that goes away.
An interesting question ... I wish there was some way to quantify the vibration. Sort of like my wife telling me she didn't like the gas stove cause it popped when she lit the oven (long time ago). So I lit it ... it went pop and the flame cam on and I closed the door and it went BOOM and blew the door open ... she sez "see it pops"
_________________
Glenn Neff
Medford, OR
87' 924S

[Lizard]

Worn engine mounts may give a vibration as stated, however when was the timing belt done last and was the balance shafts belt done at the same time? as they do smooth out the idle very slightly.

I would recommend that you install new shocks for the rear with what you are describing, as far as the mirrors shaking at speeds cant really answer that as my stereo normally caused that effect, or a broken exhaust system
_________________
3 928s,

[edh]

o/s engine mount & rear shocks sound like the favourites

if the vibration disappears above 1100-1200 rpm when stationary, then that's most likely the culprit.

I have 2 924S's
- the '86 has worn rear shocks - crashes over bumps, & is a bit loose at the back. I had the motor mount done in that one about 6 months ago
- the '88 is much firmer (better shocks & rear arb, but doesn't crash so much.

Replacement rear shocks are pretty cheap (german swedish & french do them for about £30 + VAT I think)

Is it just the rearview mirror that vibrates? (not door mirrors) - does it just need fixing a bit tighter? I can't say I've noticed that problem in either of mine.
_________________
current - '90 944S2, '00 986S,
ex - '90 944 turbo '86 924S, '88 924S

[garthfan]

I know this is SSen100's post, but since we're keeping the conversation going....This might help him, anyway.

I know I have to put some new shocks on the rear, so I shouldn't be too quick to judge. But, as much as I love my 924S -and I really do- the one thing that I am very, very unhappy with is the rough ride. And before anyone says, "Hey, it's a sports-car...." No. I've been driving sports-cars all my life. Just not Porsches. My three Mustangs, two Camaros, one Eclipse and one Celica all had substantially better suspension feel than this car does and they run the full gamut of suspension set-ups between them. The Mustangs were heavy cars -big-block '68, '70 and a '78 Mustang II with IFS and a 351ci put in by me. The Camaros were from the same era as the 924S and the Eclipse and Celica were substantially newer. All had very good rough-road feel.

Will I ever be able to get this car to smooth out the bumps??? The handling is great. Cornering is excellent -except on wet roads at high speed . It just rides too damn rough.
_________________
1987 924S - Was a daily driver...now it's GONE! *sniff*
1986 944 N/A Guards Red
1996 VW Jetta Grocery-Getter
1995 Saab 900S Winter-Driving-Feeling-of-Security-Vehicle

[gohim]

Observation Garthfan...

Mustangs, and Camaros are not sportscars... They are muscle cars.

A cushy ride is not the measure of a sports car, driving performance is.

If you want a cushy ride, buy a Cadillac, or a Lincoln, or a Mercedes sedan.

[edh]

one more thing - at speed (80-100 mph) - the car should still feel solid & smooth. I'm amazed how "modern" the car feels when on the motorway
_________________
current - '90 944S2, '00 986S,
ex - '90 944 turbo '86 924S, '88 924S

[SSen100]

First of all thanks everyone for their input – this is site is excellent in the support you can get from fellow 924 owners. Some further comments if anyone wants to come back:

MOTOR MOUNTS
For the symptoms described, motor mounts certainly seem to a possible cause. I tried shaking the engine by the valve cover as advised – not much movement. Will get this looked at. Anyone in the UK got an idea how much this might cost?

REAR SUSPENSION
Will get rear control arm bushings and rear stabilizer bushings checked out.

STEERING
I thought the steering was fine (except the PAS unit groans near full lock, not a factor here I would have thought) but one thing I noticed recently is that if I steered and braked firmly (not really hard) the car pulled quite badly.

WHEELS
Had a wheel rebalanced recently – no discernable difference.

EXHAUST
Has a new, aftermarket rear exhaust section (UK drivers will know Kwik-Fit) – maybe there is interference at extreme suspension movement.

REAR SHOCK ABSORBERS
I will get these replaced – will probably have to come MoT-time in September

BELTS
Belts were changed on 98,500 miles (less than a year ago), current mileage 102,000. Engine seems very smooth although I haven’t compared it with anyone else’s.

IDLE
Vibration is bad at idle. Just touch the pedal for some moderate revs and vibration stops – more evidence that it is the motor mounts?

MIRRORS
It is the driver’s side door mirror that has the shakiest view – will re-check its fitment.
View from the (newly re-fitted) internal one is not great, though.

REFINEMENT
I haven’t got the background with Porsches or other sports cars to comment too far – hence my question in the first place. What I would say is that the engine is very smooth most of the time and the ride is OK-ish most of the time also. Long motorway journeys at 80 mph+ are great, you sit comfortably and in control, without slouching.

I have another, (more modern) car – Seat Leon Cupra. (For those of you in the USA who might not have seen it, that’s a 180 bhp VW Golf clone from Spain.) It is not much more refined (although it has A/C). At least it doesn’t vibrate. Ride is not great but handles nicely enough. It has fantastic looking, leather electric seats but for the life of me I cannot get a seating position anywhere as good as the Porsche’s! I always get cramp in my left leg after a long journey in it.

The vibration under certain conditions and the sudden crashiness of the suspension lead me believe there was a problem with my car and that this was not a general problem with the 924.

[garthfan]

gohim...do me a favor: Don't reply to any of my posts. You're obviously an absolute idiot who loves being high and mighty and lording over everyone else...and I can't believe I'm actually going to bring myself down to your level.

I do believe I mentioned a couple other cars that I've owned besides the Mustangs...although I did NOT mention the scores of sports cars I've had the pleasure to drive without actually owning.

I did NOT say I didn't like my 924S. Nor did I say I wanted a "cushy ride." Those were YOUR assumptions. I simply pointed out that the car rides very, very roughly. Don't propogate antagonism when none is needed. You only come out looking like a jerk in everyone else's eyes.

My Porsche is a fantastic little car with a good, strong engine that gives plenty of driving satisfaction.
_________________
1987 924S - Was a daily driver...now it's GONE! *sniff*
1986 944 N/A Guards Red
1996 VW Jetta Grocery-Getter
1995 Saab 900S Winter-Driving-Feeling-of-Security-Vehicle

[gohim]

garthfan,

If you don't want comments to your ignorant statements, don't post.

The Rustang and Crapmaro still aren't sportcars. Never have been, never will be. I have no idea why people that were born after those cars were built consider them to be such great cars. Most of those cars never came with the big engines that make them go so well now, the Rustangs were mostly the inline sixes, and the overweight Crapmaros rattled like tincans with the weakly sixes, and four bangers. They may be considered classics now, but the ergonomics and the build quality were poor even when they were new.

I didn't mention the other two cars you listed (Celica, and Eclipse) because they could be consider sporty type cars by some people.

[garthfan]

That was the single most pathetic attempt at a comeback that I have ever read. Come on, man...if you're gonna' get in the ring base your arguments on fact, not emotion.

Since I stated that my Camaros were both from the same era as the 924S, that certainly means I was born long AFTER the cars were made. Pay attention to what you're reading from now on. Bad little 'him. And at least one of my 'Stangs was also made AFTER I was born. But is that really relevant??? Next you're going to tell me that the F-14 Tomcat is NOT that good of a plane despite it's tremendous success record since being deployed for the first time in December 1970!!!! How the hell does age matter???

And I did quite clearly state that the cars I had were big-blocks and very, very sporty. I would put them up against my Porsche any day of the week and twice on Sunday. It's absolutely irrelevant what any other version of Mustang and Camaro might be out there when I was specifically discussing MINE. So who's the one being ignorant???

And another thing...Ignorance. Not once since I joined this board have I made a comment that was blatantly ignorant about anything. I CHALLENGE you to review my posts and find one. In any case where I may have been incorrect, I have posted to that effect. Find a spelling or grammatical error in any of my posts. Find a patently ignorant statement. Believe me, you do NOT want to compare brain-pans with me. That's the one area where my ego really gets loose. I haven't been in middle-management since the age of 24 because I'm ignorant. Companies don't pay me good money to consult problems in my chosen field because I'm ignorant. Twenty-seven guys who are twice my age do not report to this 27-year-old because I'm ignorant.

Unfortunately, I may be hurting my own argument here because going through this crap with the likes of you is certainly pretty ignorant. (Not really, considering the literal definition of the word, but you get my point.)

I know you don't like to be beat, gohim...few people do. But, shake it off and get over it. You're not the only one with a brain and an opinion.

***My apologies to everyone else. I haven't gotten fired up like this since I joined the board and I hadn't intended to this time. But, like so many of you, I'm sick to death of having this guy put down everyone he comes in contact with. ***

gohim...I'm gonna' let you have the last word on this one. Whatever it is you may write in reply I will not answer. So say whatever you like. The rest of the board members already know your history and I'm pretty confident of where their views of you stand.
_________________
1987 924S - Was a daily driver...now it's GONE! *sniff*
1986 944 N/A Guards Red
1996 VW Jetta Grocery-Getter
1995 Saab 900S Winter-Driving-Feeling-of-Security-Vehicle

[Lizard]

Garthfan and Gohim, we need no flaming wars here, I thought you learned that when you had the last one with another member Gohim,

if you dont like his comments Garthfan, do as the rest of us do IGNORE THEM, or settle these disagreements OFF the board.

Moderators if this continues please lock this thread.
_________________
3 928s,