How can I tell how much the rear susp is sagging ?

I was wondering if there is a way to tell if (or how much) the rear end of the car is sagging. Since I had the front end rebuilt, I need to do the rear sometime.

Is there a way to measure, say, the difference in fender height (front vs. rear) , or some other way.

The front is way higher, or appears higher, than the rear. Here is a good example of the car stationary at a race.

My goal is to lower the entire thing for racing. In the back of my mind I was just going to cheat and put in lowering front springs to bring them back to somewhat level height. If the rear was sagging 2" I could use 2" lowering springs to at least get it somewhat level. I'll worry about doing it 'right' later. Only so much cash on hand. Got to save some for a roll bar too, since the new race tires have wonderful grip, that increases the chance of a rollover.

I just have no idea how to tell if/how much it is sagging. Can only tackle one thing at a time.

Paul

Just measured the car. From the floor to the fender was 27" front and 23 3/4 rear (~3 1/4 difference)

Paul

Paul:

I've been looking for a "spec" for that also. I am sure that my GT is low front and back and just looks OK because it is evenly sagged. I think that 14 1/2 to 15 inches from the wheel center to (the bottom of?) the chrome trim strip is what I have heard so far. Measuring to the wheel center will eliminate the variable of rim nd tire sizes from the equation so you may want to measure there for reference.

Manning

How about putting a level along the bottom of the sill (underneath door... underneath car ? ). A longer level like a framer's level would be best, but a two foot level will do. I would expect the chassis between the front and rear wheels to be relatively level... course I could be wrong. Its all theory since I am at work and can't actually check this right now.

>>Measuring to the wheel center will eliminate the variable of rim nd tire sizes >>

thought of that after I posted the message..oh well..but you get the idea, the car looks (to me) far too high in the front (or far too low in the rear).

To me, in the photo of your car, it looks perfectly level. Are you sure you aren't seeing an optical iillusion? The front wheel arch is much closer to the chrome strip than the rear.

It very well could be OK. This is the reason for my question. How do I check. This also applies to after I lower it, how do I check to see if it is still at the right level.

Should the wheel center be the same distance from the chrome strip?

Just looks off to me. Working under the car, the leaf spring looks almost flat compared to my truck which is arched. This is my first B, I have no idea what is normal on this car. Give me a 92 Accord, I can tell you if anything is over a 1/16" off from spec. But I have no clue on my B.

It could be dead on b@lls accurate...or off a lot... I have no idea.

I am interested in doing things right ...after decades of hacking... be nice to get it right for a change.

Paul

Your car looks pretty level to me. Look at the distance from the sill to the ground - it looks from front to back to me. Could be that you're "feeling" that the rear is lower while driving. Maybe the springs and bushings are a little soft after all these years. Not enough to matter when sitting still, but enough to squat a little more under hard acceleration/cornering than when new...

I have a 78, and as far as I know the suspension is original. It measures 15" from the wheel center to the bottom of the chrome strip at the front and 15 1/2" at the rear. Does this help?

Mine is 15 ¾� in front and 17 ½ � in back. The front and rear suspension is all new with about 10 miles on them right now. The back of mine looks high, I need to get some miles on it before I will know where it�s going to settle at.

Sure, that helps. Is this really the way this is to be measured though? Not to scientific. Can't believe that they would use a trim piece to check for ride height. That also assumes that the PO installed the trim correctly and the body work is correct. At least it is a start though.

My front end was rebuilt using poly and V8 bushings, I have no idea of that affects the height or not. I'll remeasure when I get home to check the front/rear height against the strip.

I just keep thinking if I lower the car about 2", you will barely be able to see the top of the tire on the rear.

Paul

Either put your equivalent weight in the driver's seat, or put yourself in and get a friend to measure ground to bottom of sill just behind the front wheels and just ahead of the rears. Ideal is the same number four times. Better yet, find a good race mechanic to do that and also to check the corner weights (each corner weighed seperately). Again, ideal is all four the same. Reason you want a race mechanic is once you have these numbers he will have the knowlege to tell you what to do to the car to get closer to the ideal, and the skill to do it or help you to do it.

>>Mine is 15 3/4� in front and 17 1/2 � in back. The front and rear suspension is all new with about 10 miles on them right now. The back of mine looks high, I need to get some miles on it before I will know where it�s going to settle at.>>

Did you rebuild it, more or less, back to stock? Did you use lowering springs, or anything else (non-lever shocks, etc)?

Paul

>>Either put your equivalent weight in the driver's seat, or put yourself in and get a friend to measure ground to bottom of sill just behind the front wheels and just ahead of the rears. Ideal is the same number four times. <<

Should the tire pressure be the SAME in all 4 wheels, or factory settings (27/32)? Don't know if that would affect the measurement.

Paul

One more thought (which you may already have done): If you are running SCCA Solo II, buy and read carefully the specs for Street Prepared. I haven't run DSP in 11 years so I have no idea what the rules say about lowering and what the limits might be. It would be very dissappointing to spend a bunch setting this all nice and then find out you had modded yourself into Prepared or Modified.
For those who don't know, the cars are seperated approximately into the groups Stock, Street Prepared, Street Modified, Prepared, and Modified. IMHO, SP and SM are by far the most fun classes to be in, with SP being just a little past stock, and SM being street legal race cars.

I used all stock parts and springs with the exception of converting to tube shocks.

for street prepared, here are the rules for suspension:

Ride height may only be altered by suspension adjustments, the use of spacing blocks, leaf spring shackles, torsion bar levers, or change or modification of springs or coil spring perches. This does not allow the use of spacers which alter suspension geometry, such as those between the hub carrier and lower suspension arm. Springs must be of the same type as the original (coil, leaf, torsion bar, etc.) and except as noted herein, must use the original spring attachment points. Coil spring perches originally attached to struts or shock absorber bodies may be changed or altered, and their position may be adjustable. Spacers are allowed above or below the spring. These allowances permit multiple coil springs, as long as they use the original mount locations. (7/2002).

Don't know how often it is updated..but here are all the rules:
Street prepared

Changing springs is legal, the way I read it. You can also change out the lever shocks for regular shocks (probably won't do for a while, if at all). Wheels and tires are unrestricted for the most part

Think I am safe. I can't believe anyone would challenge me. I don't race in any national or regional events. Just local SCCA clubs (NER and NESCC)

Paul

Racing pressure. Straining my poor memory, I think I ran 35 on all corners in 205/60-13 Comp T/A R1 in DSP in the Pinto (apprx 2800 lbs). 'Twere me, I'd start at 30 lbs next event, then make the 2nd run at 32 or 33, then 35 for the third, unless the second run is a lot worse feeling, in which case try 28 on the third. Tire pressure for Solo II is much higher than for road racing (or hiway driving) because the tires don't have time to heat up.

was running 27/32 on the kumho victoracer tires (195/55/14). Didn't roll over the sides (makred the sidewall). Still need to tweek the pressures though. Was understeering a bit, got to try a bit higher in the front next time. By contrast, I was running 44/38 in my Accord.

Paul

Okay, here's the info:

1st, you measure from the center of the hub to the bottom of the chrome strip.

&, the measurement is entirely dependent upon the vehicle weight and weight distribution. But, specs with 50/50 weight distribution is:


Chrome Roadster: Left Side: 13-9/16"; Right Side: 13-3/4"
Chrome GT: Left Side: 14-1/8"; Right Side: 14-1/4"
Rubber Roadster: Left Side: 14-7/8"; Right Side: 15"

" ...or change or modification of springs..." Yup, you can change springs.
I guess I'm a little spoiled having a professional race car mechanic for a next door neighbor, but I'd still say ask around at the next event to see if there's a good shop who can make those measurements for you, and reccommend possible changes.
One other possibility might be lower profile tires (unless you're already using xx/40 or something). A ten or fifteen drop, specially if you are on xx/70 or xx/75 tires, may get you down to where you want to be on the track and still allow clearance on the street.

>>One other possibility might be lower profile tires <<

Just used my Kumho race tires for the first time this past Sunday (195/55 - 14). The car had on it 175/70/14 street tires. A rough measurement was about 1 1/8" lower than the street tire. Don't have pictures, but the car looks so silly. The gap looks even worse on the front fender.

Made a world of difference. Like 15 seconds on a 70 second course. Went from last...way last...to first..by a few seconds. I was quite pleased...Problem is now the next few seconds will cost a lot more I suspect. Still got to tune the nut behind the wheel first. But still got to get the car out of the dark ages too, as funding permits.

Favorite quote: "Speed costs. How fast can you afford to go?"
Sounds like the wheel nut is in fair shape. At least you know where you want to go and have some idea how to get there. It's frightening how many people think "fast" = "power" and totally forget about getting that power to the ground in a smooth and even manner.

Got a clue..not a pro by any means. Don't want to spend $ foolishly. Just see so many other drivers showing off their bolt on air intakes, 18" wheels on their civics, cool yellow wires and hoses...yup..that puppy will rock. Keep it simple, imo. do what is known to work first.

Look at the results:
NESCC event 5 results I finished 75th (of 103) pax (adjusted) time. Not bad for a car with 50 hp at the wheels (or whatever it is) on a tired engine

I beat out 2 S2000, 350Z, new Mini, etc. power<>speed all the time. The driver has more effect, IMO than the equipment. A good driver in a crappy car should/will beat a lousy driver in a good car most of the time

Paul

Check this guy's rollbars out. They seem more substantial than most and are pretty reasonably priced also
<http://oldecabinspecialties.com/oldecabinspecialties/index.html>

For roll bars, you can't beat Kirk Racing

<http://www.kirkracing.com>

Thanks for the info on the bars..I'll give them a call...

Here are the measurements from my car

Front left 16.0" right 16.25"
Rear left 15.5" right 15.5"

Certainly looks like there is a larger difference visually..

Paul

Paul, I can't stress it enough... for what the lowering springs will run you, you can probably get a CB crossmember, and it's a whale of a better way to do it.
For that matter, if you no somebody who's good with such things, they MIGHT be able to cut the spacing blocks off your RB crossmember. I just don't think dropping lower springs in it is going to get you where you want in the most time and cost effective manner possible. Dropped spindles MAY be better, I don't know. Seems to me that the x-member is the problem, and that should be the first thing attacked. Then you can always go lower later, should you want to.

I would also strongly recommend AGAINST tube shock conversions, especially at the front... the only ones any good (the coilover conversions) will definitely bump your class. The regular tube shock conversions (for the front, at least) are junk.

replacing the xmember just is not going to happen in the near future. It may happen sometime, but changing the springs will be quick, easy and cheap. My first concern is safety. When I have corner workers tell me I look cool raising tires off the ground..I worry...Roll bar is first in the budget....can't race dead.

Still my question was how do I determine if the rear is sagging. We had a discussion a while back about lowering it. Still in the back of my mind..but unless there is a mechanic willing to do the labor for free...ain't gonna happen any time soon. Most complicated thing I have done is replace brakes..once..not a chance I could do it.

for FSP, shocks conversions are legal. Changing the xmember is not. I would be put in a mod class..probably sm2. Coilovers might be legal. not sure, not going to do that..soon..anyway..again..no cash of that level. Just want to do things slowly, as my budget will allow. Keeping the lever shocks for a bit.

I autox just for fun. I don't make a living doing it.

2" lowering springs have got to be better than original RB ones. Just using the race tires lowered it over an inch - big difference...cost nothing (since I already owned them)...

This is a work in progress..I have no plan on doing it overnight...Still got to fix me first...have a safe car...and have fun..


Paul

Well, if you can find one it's not a difficult job. We could walk you through it. You have to take the suspension apart to put springs in, so it's really only a few more bolts. Reading the rules you posted above it looks like it'd be perfectly legal, too. It's a stock piece. I know I keep pushing you on this, but the lowering springs are going to hose your geometry, I think. You'll definitely lose travel with them.

Lemme see if I can find any other help here.... On my 77, I tended to run pressures as high as 32F/36R. Running the rear higher seemed to work better for me, but then, that was a lowered car.

Sway bars... I don't know for sure, but you may want to look at junkyard RX-7s.... seems like I heard their bars can be pulled over pretty easy.
And the cheap (and good) answer on leaf springs is to have them re-arched. Good spring shops usually work more on large equipment, but they'll have no trouble with the B, and they can set them to any height and spring rate you want, within reason.

If it looks goofy it's sagging. If it looks good it's right. Scecs schmecs, who cares as long as it looks right?

Jees Paul! There is only one way to install the trim and that is in the original holes! Why are you making things so difficult?!

>>There is only one way to install the trim and that is in the original holes! <<

How do I know that the replacement fenders that are on the car:

* have holes from the factory
* and they are at the correct height
* the installer didn't have drill them in and make them too high or low??

People make mistakes, as well as aftermarket parts mfrs.

Look at my car, there were no holes for the side marker lights and were never installed by the PO (good...IMO) , WHY would I expect there to be holes for the trim???? I would expect NO holes, and they would have to be body shop drilled out to match the rest of the car. If the body shop/installer had to drill the holes, how would I know if they were dead on B@lls accurate? I don't. I don't think the trim on my car lines up anyway.

The few aftermarket fenders I have seen (a friends accord and my mother's Ford) didn't line up correctly, and the trim holes for the side fender trim didn't line up with the door..off about an .75 inch. Took a lot of fabrication to get them to fit, and the ins. co ended up buying an original ford fender for my mother because the fit was terrible. I do not know what the PO or his body shop did to my MG, if it is correct or not.

so forgive me if I question the logic of using removable trim pieces to tell if the car is sitting correctly.

Again, I have zero experience with MGs and MG body work. Which is the reason for my question. I would have thought there would be a more scientific way of telling if it is sagging, thats all. If you measure the trim to the wheel center, so be it. Just asking. I have hacked all my cars my entire life, for once I would like to learn the correct way of doing something.

Paul

Gonna to that measurement this weekend. Mine was lower on driver side than passenger. Put in new rear springs and looked fine for a while but looking at it this morning before I drove in it looks like the left side is lower than the right again by inch with no one in the car.

It's (the removable trim pieces) about as accurate and repeatable as the rest of the car. I'm afraid that your Audi past may have conditioned you to think that there is a set of engineered drawings somewhere that can be analyzed and reworked. Ain't so with the B. The factory was slapping them together in those last desperate years. Even the axle locations were approximate. As JDW said "Scecs schmecs, who cares...". I admire your tenacity but you're chasing a .... (insert Weimerism here). Trust your own judgement and sensory feedback and just go with it.

Paul, I personally like a B to have the trim strip as straight as possible, or maybe a slight rise to the rear. Looking at yours, yes, to my eyes it looks slightly low to the back. This is good for you.... leave the rear alone and lower the front, and all will be well.

Paul: If you need to measure the ride height and are not comfortable with the chrome strip you can try this: Establish a parallel line from the ground and the center of your wheel hubs. Next establish a parallel line, with respect with the ground, along the body, just above the fenders. Measure the distance between the two lines at the front and back of the car. It they are the same then your car is level.
Good Luck