Ride height - factory measurement method

[stlrj]

Originally Posted by GMR911

... but the car handles like it never did before. Probably one the most noticeable improvements I made. Based on my car, I think if one sets the ride heights to those mm specs one can expect those fender height measurements, Jerry

I noticed the same thing too, handling wise. Where I noticed the most profound difference was on the freeway 180 degree onramp. Hardly any front tire squeal like before, tracking like on rails even when I punched it coming out of the turn.

Hard to believe that simply raising to euro factory height would make such a big difference.

[Walt Fricke]

This suggests the factory knew something about suspension settings, doesn't it?

For one thing, you can only correct for bump steer using the simple rack spacer method for a limited amount of lowering. Beyond that, you either accept more bump steer, or you use a more expensive bump steer correction method up front.

Front and rear, the more you lower the car, the more the camber change curve moves, and you get out of the factory's range. You can adjust static camber back to spec (unless way lower), but where you are on the curve you can't change as a practical matter.

Racers can get away with additional lowering if they can deal with the bump steer by using super stiff springs (torsion bars are springs, essentially), because the stiffness minimizes suspension travel, which minimizes camber change. They may feel that the reduced frontal area and reduction of air flow under the car outweigh any suspension deficits unusual lowering may present. Go karts, with no springing other then the chassis, are the epitome of this approach. But you can't do this with a street car.

Me, I never trusted the fender lip method because my '77 got flares welded on in the rear, and is on its second set of fenders up front, and things aren't likely to be all lined up. Even assuming the factory checked fender lip heights before the cars went off to dealers.

[stlrj]

I thought I'd mention an unintended consequence of raising my front end. I had this annoying squeak from my front struts(or t-bars) that would drive me nuts at times....it disappeared.


Joe
87 Carrera

[manbridge 74]

While the 911 front end is easy to raise and lower in minutes, the static toe-in/out changes a lot with even the smallest change. Alignment or simple toe check is needed every time one experiments with ride heights.

And count me with the guys who find their fenders higher than most when using factory ride height measurement.

[gsxrken]

I'm a novice at this and I'm not under my car at the moment, but it seems like determining the center of the wheel and the TB wouldn't be too easy at home. Especially when the car has to be on its own weight at ride height, and millimeters count (literally). Any tips to find centers accurately for the DIY'r without a drive on lift?

"The measurement is defined as the distance between the wheel center and the torsion bar center."

[ClickClickBoom]

Not to be the fly in the ointment, the FSM list very specific methods of measuring ride height. I will say, after fixing the PO's kids lowering method, I put the car on the digital scales. I can and will say, it is possible to have the corner balance completely of of whack, I mean hundreds of pounds off and the ride height measured very close. Messing with ride height without doing a corner balance is not advised and contrary to the FSM.

[manbridge 74]

I like a cheap pair of plastic calipers at the t-bar cap. I drew a line on cap center and put the top jaw of caliper on it and lower the rest. Helps to drive car up on 2X10 boards if you don't have a lift. I'm not a "stance" guy so my car is not hard and requires no boards. Nothing worse than driving a badly lowered car IMO.

[manbridge 74]

Originally Posted by ClickClickBoom

Not to be the fly in the ointment, the FSM list very specific methods of measuring ride height. I will say, after fixing the PO's kids lowering method, I put the car on the digital scales. I can and will say, it is possible to have the corner balance completely of of whack, I mean hundreds of pounds off and the ride height measured very close. Messing with ride height without doing a corner balance is not advised and contrary to the FSM.

Do you mean the PO messed up the weighting or are 911s hundreds of pounds off from the factory when set using t-bar measurement? I find it hard to believe they'd be that off coming from the factory.

Can you explain a bit further about FSM's corner balancing during ride height setting?

[Arne2]

Any time there is a significant change in ride height, the car should be corner-balanced. The factory indicates that very small changes to the front height - done equally - MIGHT not require re-balance, but anything more than a tiny bit, or any change in the rear requires it. 1mm difference can equal many pounds difference in wheel weight.

[ClickClickBoom]

Originally Posted by manbridge 74

Do you mean the PO messed up the weighting or are 911s hundreds of pounds off from the factory when set using t-bar measurement? I find it hard to believe they'd be that off coming from the factory.

Can you explain a bit further about FSM's corner balancing during ride height setting?

Well,
Arne is right. While correcting the POs messed up lowering attempt, I adjusted the ride height, then put the car on my digital scales. The weights were so far off, it was crazy wrong. When I balanced the weights the heights were within 1/8" ride height. There is a plethora of absolutely wrong, and wives tale's information available. These cars are adjustable to allow tuning of the whole enchilada, do it wrong, and it will be like any other poorly handling car out there.
I have close to $1000.00 worth of FSMs on my shop shelf, early, mid and Carerra. I also have on my iPad the same FSMs and the PET, do yourself a huge favor, access the info either through the internet or buy the manuals.
Or just ask any schmoe for their opinion......

[manbridge 74]

For the track or street?

I'm all for CB. Just wondering how it could make such a difference or what the symptoms of an unbalanced car might be. Ie, does it turn easier in left hand turns vs right? Etc.

[manbridge 74]

Originally Posted by ClickClickBoom

Well,
Arne is right. While correcting the POs messed up lowering attempt, I adjusted the ride height, then put the car on my digital scales. The weights were so far off, it was crazy wrong. When I balanced the weights the heights were within 1/8" ride height. There is a plethora of absolutely wrong, and wives tale's information available. These cars are adjustable to allow tuning of the whole enchilada, do it wrong, and it will be like any other poorly handling car out there.
I have close to $1000.00 worth of FSMs on my shop shelf, early, mid and Carerra. I also have on my iPad the same FSMs and the PET, do yourself a huge favor, access the info either through the internet or buy the manuals.
Or just ask any schmoe for their opinion......

Well I have the FSM for my car (74) so I was thinking the later manuals might've went into more detail.

So to understand, you set the RH then the weights and were left with 1/8" of difference side to side?

[ClickClickBoom]

Originally Posted by manbridge 74

Well I have the FSM for my car (74) so I was thinking the later manuals might've went into more detail.

So to understand, you set the RH then the weights and were left with 1/8" of difference side to side?

Just one of the symptoms of an unbalanced car would be one wheel locking under braking, and not under heavy braking, that's what prompted me to correct the idiot lowering attempt. If you have only the mid year supplements, you will need the red early year FSMs to get the additional info. The FSM says any time the TBs are messed with for ride purposes a CB is mandatory. If one doesn't drive more than a few days per year and never get above 45mph unless in a straight line, I guess you can skip the CB, otherwise it's not an option.
Sorry if I am terse, this subject reminds me of another forum where a poster was arguing as how to prevent detonation in a diesel.....do your own home work and decide for yourself, like Bill said.

P.S. Correct, set ride height, then adjust for corner weights, the FSM list tolerances for ride height and CB, my numbers are on the shelf in the shop.

[manbridge 74]

I can certainly agree that driving a poorly set up 911 is terrible and people get confused when so many adjustments are available and they don't do this sort of thing for a living. Heck, it's easy to screw it up if you do it for a living and you aren't meticulous. I like having the adjustability though and might CB my car or use the tripod method some day. So far it has tracked straight and seems to have no handling/braking issues even though I've removed at least a 100# of weight from all over the car. But then again I don't track it though I've pushed her into triple digits numerous times. Maybe I'm just lucking out here.

And no terseness noted by me. Thanks for the explanation.

[GMR911]

When I first p/u my car I was kind of disappointed by the at how high the car sat based on what other's were showing their cars as euro height. But after seeing the results of the ride height, corner balance and driving the car I was completely satisfied. I also looked at old pictures of my 66 911(which sadly I sold 33 years ago) and heights my 77 looked very much like my 66(which I guess back in 66 all 911's were "euro" height. Like Walter says maybe the factory knows where the settings are supposed to be for street 911's. Jerry

[Arne2]

My '84 was too low when I bought it, bottoming easily in front. No idea when it was last corner balanced. I raised the front a touch, knowing full-well that if it had been balanced I was screwing it up. Ride improved significantly from having more travel. Will be time for new tires next Spring, I plan to have it raised another 10-15 mm or so and properly corner balanced then.

[stlrj]

I found the best way to raise the front end without screwing up corner balance is to make sure your rear fender heights remain equal. For example, if you found the RR lower than the LR, it means your LF was adjusted up too high and will need to be let down a bit or have the RF raised up slightly. Whatever you do up front effects the rear height diagonally, so as long as the rear heights remain equal, you're corner balance should be in good shape.

[stlrj]

For some of us who are not used to seeing what true factory European height looks like, here is an example I found on You Tube.

Porsche 911 Carrera 3.2 Targa (1988 commemorative edition) - YouTube