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Maximum negative camber -1°13' on right front

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Old Aug 24, 2021 | 03:34 PM
  #1  
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Maximum negative camber -1°13' on right front

Hi guys,

I encountered a problem with my 94 FD during the last suspension allignment on a 3D allignment hoist.

On the right front, the front excenter is at its most outward position, the rear one is a little bit less outward:

front:


rear:


I had expected, that in this position I get nearly the most possible negative camber. But the reading was only -1°13'. On the left side the positions of the excenter are a good bit less outward, but there is already -1°30'.

The subframe looks perfectly straight to me, no hints for any crash damage or something like that.

Any ideas, how I could tackle this problem?


Last edited by Namxi; Aug 25, 2021 at 01:02 AM.
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Old Aug 24, 2021 | 09:16 PM
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Photos arent showing up for me.
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Old Aug 25, 2021 | 01:06 AM
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Fixed it, or have I?

Thanks for the info!
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Old Aug 25, 2021 | 08:05 AM
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Yep, pictures are showing now.

I'm trying to figure out what you are trying to accomplish. First, the adjustment bolt is possibly damaged. I think there were 2 versions of that bolt, one was easier for the locking mechanism to strip. That could be a factor in why the front and rear of the bolt are funny.

Second is are you trying to get more negative camber, like setting up for a track car? Or just trying to get a proper alignment?

Dale
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Old Aug 25, 2021 | 08:47 AM
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Yes, I'm trying to set up a track car, a minimum of -2° camber would be nice. I believe I already saw this number on the left side when they where trying to allign this side.

The pictures show the bolt-side of the front "camber" bolt and the bolt-side of the rear "caster" bolt. So two different bolts.

I'm planning on taking everything apart and look for damage, but I would like to have a plan b, if everything looks fine.
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Old Aug 25, 2021 | 09:58 AM
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FYI, here is Pettit Racing's recommended alignments -

https://www.rx7club.com/3rd-gen-arch...-specs-182680/

That's a LOT of negative camber you are going for, I don't know if the chassis is engineered to do that much. Also with some of those settings a tiny bit in one spot make a big difference in another spot.

May need to get some of the track junkies in here to chime in. Maybe @Fritz Flynn ?

Dale
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Old Aug 25, 2021 | 10:15 AM
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If going for a track only alignment my memory is a 2.2 front 1.8 rear

neutral toe front and a 1/8 total toe in rear

That said there are lots of different ways to set your car up depending upon tire size, grip, spring weight, your driving style, the track etc...etc...

The pettit info is more for street/track cars.
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Old Aug 25, 2021 | 11:54 AM
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Yeah I think I'm at 2.4 front, 2.2 rear, 1/16 total toe front, zero rear, 5.5 caster.

You could go down to 2.0/1.8 or less if its street tires/application, but per Fritz the Pettit specs are super conservative

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Old Aug 25, 2021 | 11:58 AM
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This is what I'm running on my FD for autocross. Our tracks are very small and super tight (think small grocery store parking lot) and you can do 90% of the courses in first gear.

265/35/18 square on 18x9.5 +38 rims.

Front:
-2.5* Camber
+7* caster
2mm toe out

Rear:
-2* camber
2mm toe in
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Old Aug 25, 2021 | 03:04 PM
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It'll be a track car mostly for german GP tracks, so 100-125+ mph on the straightaways and 60-90mph through the corners.

So with that settled, any ideas why I can't dial it in at the right side of the car? Are there any cheaper ways to get "more" camber expect for the camber kits from hardrace and co.? Maybe some camber adjusting poly bushings?
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Old Aug 25, 2021 | 06:27 PM
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Have them come in on the forward one in the front a bit (less caster) and see if that buys you some camber. There shouldn't be any issue getting 2 degrees but all of the settings affect each other so you may need to have them finagle it a bit.
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Old Aug 25, 2021 | 06:34 PM
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Autocross I’m corner balanced with these settings. I have 9.5 in front with 255/35 and 10s in the rear with 285/30. National competitor wanted me to do -2.0 and I reigned him back a bit. This setup feels extremely good!




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Old Aug 26, 2021 | 03:30 AM
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Originally Posted by ptrhahn
Have them come in on the forward one in the front a bit (less caster) and see if that buys you some camber.
I thought the front bolt is primarily for camber, because it is on axis with the hub. This was also visible on the allignment hoist, less outward on the front bolt meant less negative camber.

But I also just found this:

(SuperPro SPF4623-80XK)
But I'm not sure wether they work with the OEM excenters, because the hole looks fairly small. But as mentioned before, I have to take the excenters apart to understand, how they work. Will do so on saturday.
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Old Aug 26, 2021 | 07:27 AM
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I may have that backwards (haven't had my car in a while) but the point is, the settings are inter-related so they may need to futz with it. You should absolutely not need special bushings to get the camber you're looking for so if it can't be solved I would look for potential damage.

P
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Old Aug 26, 2021 | 06:13 PM
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What's your ride height? That will play a large part in your camber curve. Usual issue is in trying to get the desired camber, you lose castor. Fronts here run mid 3s, but that's with a modded subframe.

Superpro eccentics, they used to (still?) offer upper wishbone ones, which will probably have less chance of slippage with less load imposed. No experience with them on FDs, but have heard on other cars if you're aggressive in attacking ripple strips, eccentric bushes generally, can slip.
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Old Aug 27, 2021 | 03:38 AM
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Ride height I would say normal to low:



But I just went up 4mm in the front and 10mm in the back, because the tyres rubed on the last trackday. But since ride height is even on both sides, this shouldn't be the root for my problem.

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Old Aug 27, 2021 | 11:34 AM
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Some comments and input based on your posts and feedback from others in an attempt to help....


1. The eccentric bolts and washers do wear out. The symptom for worn eccentric bolts and washers is that the bolts loosen and also that the teeth in the washer part wear and don't allow the eccentric bolt to hold a position. I don't think you are experiencing either problem in your case but eventually you might want to replace the eccentric bolt and washers.

2. Generally, you will want to max out the eccentric primarily used for camber (front). You can literally see the control arm move in and out as you twist that eccentric bolt. Double check that it is rotated in the correct direction next time you are on the rack but I suspect that it might be correct already.

3 The rear eccentric will affect both camber and caster. Adding caster generally adds camber iirc... You can use that to add a little more camber if needed while adjusting caster to where you want it. It probably will not provide you with the missing 1 degree of camber though.

4. You don't need a lot of caster. I think I run 5.5 - 6 degrees. I found 7 degrees (which is about the maximum the components will provide) didn't feel good in the steering wheel - steering required too much effort. Of course that is driver preference.

5. It could also be that the bushings have some wear. They look centered in your pics but hard to tell what it looks like under load with the car's weight on the tires. For track use, some stiffer than stock LCA bushings are an improvement IME / IMO. Especially since the rear bushing is liquid filled for better NVH in street use.

6. A slightly bent upright can impact camber readings. I experienced that with my Miata race car once when an off track excursion resulted in a broken wheel, tweaked upright and bent ball joint...

7. I vaguely remember somebody else on the forum once having a similar camber problem. I think one of his troubleshooting steps was to loosen the subframe bolts and attempt to align it centered in the holes. I think it had an impact but was not the root cause. Try searching for his thread. His troubleshooting may help you.

Good luck.
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Old Aug 27, 2021 | 02:50 PM
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I finally got the car jacked up on both sides today. The bolts look good, no obvious problems:



On the left side, the front bolt is near the middle setting, resulting in -1°31':



On the right side as stated above maxed out resulting in -1°13' (Also see picture below).

Center the subframe is a good keyword. I tried to meassure the position of the subframe left and right, but there is no good reference point besides a bent piece of sheet metal, see the arrows:



Its really hard to meassure but I think on the left side was a slightly bigger gap than on the right side, maybe 1-2mm. Is it even possible for the subframe to be out of line?

Bent ball joint is also a good keyword, I thought about that when looking at the left and right lower ball joint of the wheel carrier. It looks a little bit of on the right side, like its slightly bend upwards. What exactly do you mean by "A slightly bent upright"? I a have a hard time translating this. Do you mean the upper wishbone?

I will search for the old thread, maybe I'm lucky and there is a solution.


Thank you guys so much for the help to this point, this forum is just so unbelievable good!
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Old Aug 27, 2021 | 03:20 PM
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The upright is the part that includes the stub axle and the wheel hub is attached to.
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Old Aug 27, 2021 | 05:02 PM
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From: https://www2.mazda.com/en/100th/
Originally Posted by Namxi
What exactly do you mean by "A slightly bent upright"? I a have a hard time translating this. Do you mean the upper wishbone?



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Old Aug 27, 2021 | 06:25 PM
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Detailed on here in the past I think, we had an instance of installing a bent lower wishbone and couldn't get alignment for love or money. Wasn't visible to casual observation, short of using plumb bobs, put the old one back on, voila, camber and castor numbers good again.
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Old Aug 27, 2021 | 08:05 PM
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Old Aug 27, 2021 | 08:26 PM
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Originally Posted by Namxi
Ride height I would say normal to low:



But I just went up 4mm in the front and 10mm in the back, because the tyres rubed on the last trackday. But since ride height is even on both sides, this shouldn't be the root for my problem.
Pete's numbers are a bit more accurate than mine for a 285 30 18 tire size with r7s and say 700 to 900 pound springs.

I run 275 40 17 tires which have a 1 inch taller diameter.

The higher the car the harder it is to get negative camber.

The more grip you have and the higher the spring rate the more camber you will need. Actually the more grip you have the less camber you may need LOL?

Last edited by Fritz Flynn; Aug 27, 2021 at 08:28 PM.
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