Welmeister Camber Plates vs slotted factory?

[KSUGreggy]

I'm needing more camber in the front of my 84 factory turbo-look for the track. Car is going to kumho v710s for the track next year (no optimal I know but got a deal I couldn't pass up) and I'm sure I'll want the ability to add more as needed. Currently running Dunlop Star Specs in 205/55-16 on 7" up front, 225/50-16 on 8" in back. Kumhos will be 225/50-16 on 8" front and 265/45-16 on 9" in rear. I

Car has a Cambermeister right now but can only get about 1.5 degrees negative. Have had severe shoulder wear issues at both autox and track with Star Specs this year. Will swapping to a stiffer rear spring help this? The rear has been run at 3.0 negative with great tire wear in the back. Car has RSR coilovers currently with 600 F/400 R, these will be getting swapped 400 F/600 R this winter after discovering this mixup. I will be lowering slightly as well to help but don't want to go too low for fear of bump steer issues/loading on the trailer.

I'm contemplating welmeister camber plates right now, because of the current sale on them.

Has anyone slotted the plates/mount on their car so they can get more camber? How much can be gained without structural issues? Does anyone have photos of this done? I've tried to find but haven't had any luck with search.

Here is the best photo I have on hand. The close shoulder is the outside shoulder with the wear issues:

[175K911]

You can try taking the factory plates out and opening up the slots in the chassis. Then grind off part of the inside edge of the camber plate. I was able to get to -2.25 that way. I then installed the Tarett offset uppers but couldn't get any more neg camber because the inner edge of the part couldn't slide any further inward. But you might be limited by the overall diameter of your coils now.

The better solution is to have your front spindles raised and decambered, but that requires front Bilstein struts. Not sure what coilovers you have, but decambering the spindle will build more negative camber in.

[KSUGreggy]

These are the photos of the front setup...I see yellow so maybe they are bilsteins already?? Do you have any photos of the slotted holes for the factory plates? I'm a little concerned about any potential weakening being that the car is running coilovers vs tbars now.

[dad911]

You could replace lower ball joints with Elephant Racing De-Camber ball joints for another 3/4 degree.

Pelican Parts.com - De-Cambered Ball Joints

[Fast Corners]

+1 on the Elephant Racing ball joints. Not only do they give you extra camber they widen the front track of the car.

[KSUGreggy]

would you do ball joints over camber plates? I assumed camber plates would easier to install if I'll already be taking apart the coilovers to swap springs anyways?

[Fast Corners]

Have you checked your clearance between the inboard side of the strut tower and the coil-over? Using the camber plates and/or slotting the strut tower will move the assembly inboard which can cause clearance issues. You may need a coil over hat and adjust the spring perches to get this to work so you should look at this carefully as the cost may not just be for the camber plates.

As you are competing this car, the additional width in front end track that the aforementioned ball joints provide will be a benefit. 175K911's suggestions are good too but the expense is greater. Alot depends on how far you want to go and subsequently how much money you want to spend.

[Grady Clay]

KSUGreggy,

I would take an overall look at your 911M491’s handling.

Wear on the outside front is typically a ‘push’ (under-steer) issue. This is not uncommon on a 930 from low speed cornering. Keep in mind that the car is designed to handle properly at 150+ mph and gives up some proper performance at low speeds.

As delivered, a 930 is a pretty good compromise. A 911SC/Carrera M491 probably further compromises tire wear for 'look' - not a usual Porsche feature.

If you want best autocross handling, you can adjust or modify the suspension, tires and wheels appropriately. If so, you best not try full speed laps at Talladega. Jay Leno can offer you advice there.


Look at your intended use.
Research the changes that help with that use.
Know the compromises that you must make.
Know the consequences of those compromises.


Everything is a compromise.

Porsche made many compromises building in great overall handling in a powerful and fast 911. I think not loosing control at 140 mph had great influence on the compromise. M491 looks was an influence. Low speed tire wear was probably not high on the list.



There is no shortage of information helping you with your decisions. Pelican Search is your source. Your 911 is probably the most tested, researched and adjustable street car ever built. The final products were the incredibly successful 935s. I can tell you first hand that race-only compromises make for a difficult-to-drive street 911.



There is nothing wrong seeking more grip. Just like more torque and top-end power, this is what a Porsche can be about. You can’t have too much.

Tires make more difference than anything else you can easily do with your 911. That said, adjusting or modifying you suspension for the best use of those tires is critical.

Good luck with your compromises.
With care, they will be successful.

Best,
Grady

[KSUGreggy]

It's always about the money isnt it?! I'm competing but I'm not competitive except for on a local level because I will only run street tires for the autox (SCCA btw). I'm just looking for the best bang for the buck so I can extend tire life, especially now that I'll be getting sticky (Expensive!) tires for the track.

How much will a set of camber plates move it in? I know the ad says a degree or so, how much does that become at the top of the strut? Then I can get a better idea of how close I'll get to the strut tower. I'll get under the car this weekend and check that out.

PS: this car is a track only car for me with the occasional weekend drive. I've already got fairly high spring rates as is, esp compared to comparable torsion bars so it's not exactly the best DD as is!

[911st]

Look into Smart Racing Camber Kings they are excellent and made of SS steel I think so they will not crack. You can get up to about -3 with them if the springs do not interfere w the body and limit travel. The ER is great to. ER offset ball joints can get you about .75 more camber.

-3 up front w a stiff suspension sounds about right per other's I have heard from.

PS, if you are going to 265's in the back, I would look in to 245's in the front on those 8's. 911's seem to respond well to less stager front to back and might make set up a bit easer.

I think of the rear weighting 50% more than the front (40/60). If that is the case I think I need 100% of one front tire for the front to carry its own weight. Then I think I need 100% of one rear tire and 50% of the other rear. That is if the front and rear tires are close to the same width.

If the front is not pulling its weight, then traction has to be shifted from the inside rear tire to the inside front using the spring rates or sway bars. At least this is what I have come up with. This requires a more accurate balance than if we just set it up front stiff and let it run on three wheels.

205/225, 225/245 are more like 245/265.

Not an expert on this, just what I am thinking.

[Fast Corners]

Originally Posted by KSUGreggy

It's always about the money isnt it?! I'm competing but I'm not competitive except for on a local level because I will only run street tires for the autox (SCCA btw). I'm just looking for the best bang for the buck so I can extend tire life, especially now that I'll be getting sticky (Expensive!) tires for the track.

How much will a set of camber plates move it in?

Yes, unfortunatly money seems to always be an issue. Except for the rare prodegy competitiveness mainly comes from seat time. Better tires will help more than you can imagine. The key is learning to use them to their maximum potential..you are on your way though. Grady's advice is always good so I would do as he recommends and do your homework.

If I recall correctly the offset holes on the camber plates are something like 5/8" apart center to center. PM me and I can verify that if you like. Since this is at the top of the strut assembly the amount the coil will shift inboard will be slightly less but close to this value. You can see the offset holes in the picture.

[KTL]

If your front suspension is at full droop right now in that picture, I suspect the tie rod is already angled upward when the car is down on its wheels. Meaning, I suspect you're already experiencing bump steer. And that means you're already experiencing the negative effects of it (toe change during suspension travel), plus the undesirable camber curve behavior- loss of negative camber as the suspension travels upward. So the point is, you can gain more negative camber with the plates, slotting, offset ball joints, or whatever. But if your geometry is compromised, you'll still be losing some of that camber you gained with these parts

You'd be wise to invest in the raising of the spindles (further, since the RSR spindles provide some but more would help) to restore the geometry & dynamics of the tie rod, strut and A-arm system. The nice thing about decambering the struts is that it does not affect the strut top clearance that we are battling. It does however introduce tire clearance issues if you run wide wheels & tires. This is less of a concern on your car with 930 flares, because if you get tire-coil interference, you can easily install a wheel spacer to get more clearance. Non-930 front fenders are always battling fender clearance when you install bigger wheels and tires. Spacers won't work in that case because it just makes the problem worse.

If you want camber plates, i'd choose Wevo, Tarett, or Elephant (Elephant claims the most camber- so does Wevo) over the Weltmeister. Elephant's are really trick in that the camber is adjusted w/out the need to loosen the 3 strut mount bolts- one of Chuck's many smart QuickChange ideas. Wevo's are small and compact with very sturdy, light cast steel plates. The way to avoid all this BS with plates is to install camber boxes.......... But you still should look at the spindle height because that is the root of the cause- lowering of the car.

You should also have a light tender spring on those coils to keep them properly seated on the spring perches. As you can see at full droop, the spring comes away from the perch at the top

[Grady Clay]

Originally Posted by KSUGreggy

It's always about the money isnt it?! I'm competing but I'm not competitive except for on a local level because I will only run street tires for the autox (SCCA btw). I'm just looking for the best bang for the buck so I can extend tire life, especially now that I'll be getting sticky (Expensive!) tires for the track.

How much will a set of camber plates move it in? I know the ad says a degree or so, how much does that become at the top of the strut? Then I can get a better idea of how close I'll get to the strut tower. I'll get under the car this weekend and check that out.

PS: this car is a track only car for me with the occasional weekend drive. I've already got fairly high spring rates as is, esp compared to comparable torsion bars so it's not exactly the best DD as is!

Yes, it is always about money. We can’t get away from that with any car. Money = speed, race success and anything else you can think of.

I think one function of this Forum is to help use wisely the always limited money we each choose to apply to our passion. A lucky few that is (relatively) unlimited. This is not Dubai.


I have spent the past 50 years competing in motorsports and other. If you don’t have (or want to recruit) the money for something you can’t personally afford, the solution is to find your own ‘comfort level’. Never spend more than you can afford.

There is a racing proverb:
“Do you know how to make a small fortune in racing? Start with a big one.”


With good maintenance, extra tires and learning driving; you will find great success with your M491 without many modifications.

Best,
Grady

PS; Consider for autocross track - equal small front & rear tires at some autocrosses. Autocrossing with the throttle is critical.
G.

[Steve W]

The front of a 911 gains 0.1 degrees of camber for every 1.0 mm the top of the strut is brought inboard, or the bottom is moved outboard. Typically with Bilstein shocks/struts, if you were to shave the camber plates on the insides, or use offset camber plates, the strut becomes the limitation as the strut comes against the strut tower. More than about 5mm and the metal dust covers need to be deleted and rubber ones used instead. Normally you can gain about 10mm, maybe 12 if you force it, netting a camber gain of 1.0 to 1.2 degrees. However, with coilovers, you need to check how much clearance you have left between the springs and the strut tower. If insufficient, then decambering the struts, decambered ball joints, or lengthening the A-arm are your other choices.

[175K911]

OK, one thing we're all missing here, though Grady touched on it with his comments in his first reply......

You have the spring weights backwards as you know. With stiffer spring in front than in the rear, you're going to induce a lot of push, especially in low speed turns when on boost. Going from 600/400 to 400/600 will make a significant difference in your push. I might make that change first since it's basically free, other than your time to do it. Of course while the front struts are unbolted from the upper mounts, it's a good time to swap to offset mounts, if for no other reason than to get rid of the rubber bushings that deflect under load. Though as Fast Corners said, your coils could rub on the inside of the chassis if you try to dial in much more negative camber.

But right now you have two things fighting against you with the coils the way they are. First, the fronts are too stiff compared to the rear for proper balance. And second, with the rears as soft as they are, I'm sure your rear end squats big time under boost which further unweights the front and causes push.

I'm no Turbo expert but I'm wondering if you need something stiffer than 600 lb springs in the back as well.

[911st]

It is interesting but on a stock 911 and with most sport torsion bar combinations the combined front spring rate is more than the rear. Front to rear weight distribution dose not seem to be a factor as one would expect. It seems to be that the car is more like a solid plane the ft & rr spring rates should start at a more equal level and then be skewed to fit the handling wished. If more traction is needed in the rear, the fronts are stiffened, if more is needed in the front, the rear is stiffened relative to a 50/50 balance.

Also, there is leverage in the rear of a 911 so the actual spring rate is multiplied. Thus a 400/600 is more like a wheel rate of 400/725 or such. That might work with a stiff chassis, larger rear tire stager, and tight LSD. Might try it. If to rear stiff you will know why.

I think 400/600 is an often used Turbo balance. On a Turbo-Look w a lot less rear weight it might be a bit rear stiff depending on ones driving style, use, and set up. I think BBII is very rear stiff so it should be good.

225 front tires will need a soft front to pull there own with 265's on the back so it may be great.

Sorry for the ramblings. I could be off on this.

[911st]

PS,
I slotted my stock and trimmed the stock tops. With the A arms set w a little drop I got a bit over -2 deg up front. Was not enough as the large diameter top fouls the body. One could open that up to but that is getting into cutting more than I wanted to. I think I opened up the hole in my stock top to get a little more. With the stock strut top one needs the shock top or a large washer on top to keep the shock from going through the hood if there is a failure of the rubber bushing. Not so w the aftermarket tops.

This also leaves one w rubber that reduces camber a little.

http://www.smartracingproducts.com/pdfdocs/452195_camberking.pdf

[wdfifteen]

Can I step in and ask you camber experts a slightly off-topic question? I'm thinking of adding some neg camber to my 88 Carrera for tire clearance and to help autocross/track handling but I do drive the car on the street a lot. What effect does increasing negative camber have on street behavior? Heavier steering or anything? I don't want to make a mistake and take the fun out of 90% of my driving to add a little speed for the other 10%.

[Chuck Moreland]

Where to start?


Firstly, listen to Grady. He forgot more than the rest of us know – and he hasn’t forgotten much!

Now to your situation.

Coilovers
Your coilovers have numerous setup errors.

As someone said, the 600/400 springs are backwards. This will cause profound understeer, exactly what you don’t want in an autocross. Flip the 600 to the rear, 400 front and you'll at least be reasonably balanced.




You need helper springs. Note in this picture at point (A) the gap between spring and perch, at full droop your springs have come off the perches. This will always happen with stiff race springs. Problems happen when your car lifts a wheel(s) and the springs come off the perch. They will certainly make noise upon re-seating, and they may land wrong on the perches – not seating properly and causing the corner height and weight to suddenly change. Not good.

Add spring dividers and helper springs.

Toss those upper perches. Note point (B). The perch fits tightly around the bilstein insert and will bottom against the top of the strut at (C). This metal-to-metal contact will happen before the internal rubber bump stop is in play, and is limiting your suspension compression travel artificially. While this will never happen with your 600lb springs in place, once you fix that spring problem you potentially have metal-to-metal bottoming out.

You need a spring seat bearing kit. As you steer the car, the lower strut rotates (D) but the upper perch (B) remains stationary. Hence the spring is forced to wind up, or slide across the seat – under the fully loaded weight of the corner. Windup actually changes the spring seat tension (corner weight) as you turn the steering wheel, plus this makes steering effort exceeding hard. These are bad things.

Spring windup also happens when the spring compresses, even if you don't turn the wheel (compress a coil spring and you will see the end rotates). Without a bearing to relieve the windup, the spring 'binds' a bit as it attempts to slide on its seat to relieve windup.

You want a setup like this.



The helper springs are very soft and fully compress under normal conditions. But when the main spring is fully extended, and the suspension droops further, the helper extends to keep tension on the seat. The divider keeps it all concentric.

The Extended upper perch has an ID large enough to allow the strut lower housing to enter it. It does not constrain suspension travel and the internal bump stop is able to do its job.

A seat bearing kit is installed to allow the spring to rotate against the upper perch, moving with the lower perch and relieving spring windup and steering effort.

Camber

I’m not a fan of decambered spindles. Adding camber to the spindle increases the scrub radius and lowers the roll center of the car, both undesirable attributes.

You can get more camber using de-cambered ball joints, camber plates, or a combination of both.

With camber plates, you may find you are limited in camber range due to the diameter of the coil spring. The OD of the coil will hit the inside of the shock tower, limiting adjustment range.

If you use our extended upper perches, you solve the spring diameter issue. The perch is much smaller in diameter than the spring and allows much greater camber adjustment without hitting the tower. The perch gets the spring down below the narrow part of the tower.



Decambered ball joints do not have this problem, since they are moving the strut bottom out.

If you go for camber plates, I’m partial to the QuickChange Camber plates because they allow you to adjust camber easily and independently of caster. These are available from pelican.

[KSUGreggy]

Chuck/Grady, thank you both for your thoughts and experience. 911st, thanks for chiming in as well, I know you and I have talked via PMs before.

I must say I'm rather disappointed by all the mistakes that the shop that installed these coilovers did, granted they are out of commission now but nonetheless its disconcerting. I'm also suprised other shops who have worked on the car did not catch these issues either and point them out to at least make us aware.

Chuck, looking at my photo you labeled, I currently have 8x2.25 springs on there, if I put in these helpers as well as divider, bearing kit and upper perch parts, will I need a shorter main spring?

Do you sell these individual parts on your site as well?

I have significantly more work ahead of me than I though.