Refreshing rear end and more - Advice required

[MatRacer]

Hi all,


Part 1:

Just about to refresh my rear end. My car is a summer DD fun / track car. No serious racing for now, just fun on track, may 2 to a max of 4-5 events per summer.

Here is my preliminary part selection:

Subframe bushing: AKG 95A poly bushing (SF309)
Trailling arm bushing: AKG 75D poly bushing (RTAB30D)
Weld-on camber/toe plates: AKG kit (RTTC30F)

Was also looking on Esc Tuning the powerflex bushing... They have adjustable sleeved bushing like this:



Does Powerflex ones provide enough adjustment? Should I stick with AKG? Any other suggestions?

Part 2:

My car is lowered on GC sleeve. Running 350# front and 500# rear. I know its soft. Will get it stiffer at a later stage but for now its OK. Got it alligned and here are the number:

Front:
Camber --> Left -2.03 right -2.24
Toe --> Left 0.18 right 0.18

Rear:
Camber --> Left -2.06 right -2.47
Toe --> Left 0.19 right 0.18

Camber plates are not part of my winter tuning plan now... because $$...

How should I get my rear end adjusted considering my front specs? Is rear camber/toe adjustment a real benifit considering my actual specs? (Since I had the ability to weld the adjuster kit myself, thought I would do it now since the subframe will be out of the car...)


Thanks for your advices!

Cheers,

[lcoleman]

I'd go for the Ireland adjusters with the locking ridges instead of the eccentric style like AKG and Powerflex. They hold their adjustment a lot better, but are harder to set.

I would zero the toe at all corners, maybe leave a hair of toe in up front if you want. Camber plates would help handling the most (3deg up front or so), but you have an OK amount of camber as it is. I'd set the rear to 1.5-2*.

[MatRacer]

IS it a real and frequent issue that the eccentric style un adjusts itself?

But yeah, I can figure that the locking ridges are bullet proof...

[richard.bratton]

The Ireland ridged locking adjusters are far from bullet proof. I've seen them strip, bolts back out, and people tighten them with the teeth not properly aligned. I use the eccentric style adjusters in my Spec E30. Aside from a collision with another car or wall, they rarely move, yet are simple enough to adjust at the track. The secret is getting them very tight after adjusting.

[SkiFree]

Richard, this is Andrew.

Conversely, a real problem with the eccentric adjusters are those whose tabs are BENT and not machined. This means the washers either don't sit flush (because of the inner bend radius) or they don't fit snug with the shoulders. IE makes both the posi-lock and the eccentric style adjusters (machined from cold-rolled steel).

I have seen enough of either setup work great or have issues (even with some of the self-brewed fixes mentioned on r3v if you search) to know that much of it is really getting full torque on them as Richard mentions. However, in a straight comparison I have seen you are more likely to loose adjustment with the eccentric style over the serrated style (but this does not make them stupid proof). Lastly, I've learned that if an experienced shop like Richard's has confidence in one style, it is much more likely to be successful.

[MatRacer]

AKG eccentric adjusters are bent... Should go with IE then...

[3vilE30]

IMO just leave it, don't bother with the adjustable camber/toe kit. Each design has its flaws. The eccentrics go out of spec way to often, the serrated IE ones are supposedly difficult to adjust and has locking issues. I would just refresh all the bushings and see if everything aligns evenly within stock specs. If something doesn't align right then either it's bent or somethings up with the chassis.

If you really want something that'll work look into DTM Uniball setup.

If you don't want to run much negative camber in the back look at the akg riser bushings.

[SkiFree]

If something doesn't align right then either it's bent or somethings up with the chassis.

mmm ... or you've lowered your car? OP, if you want a real response from people who actually do this for a living (ie they're not perusing r3v) then definitely call some good race-prep/fab shops.

Here's a couple to start with that have actual experience .......
WotTech (FL)
Midnight Motorsports (Seattle)
Midnight Oil (San Diego)
German Motorwerks (GA)
BTM Motorworks (Bay Area)
Advanced Auto Fab (WA)
Ronin Autoworks (Fullerton, CA)
Sports Car Restoration (CT)
VSR (NH)
Terry Sayther Auto (TX)
T-Zero Racing (WA)
Munich Motorsports (WA)

[MatRacer]

Thanks! I'm located in Québec province, Canada... Don't about any speed shop that actually race E30s in Qc.

Also, subframe riser raise for like 1/2 inch...coresponding to 1/2'' less low... which I don't think has a big influence on camber.

[Northern]

I don't really want to get involved in "Part 2" but for my car, which is a summer DD/autoX toy, I didn't want to add anything that causes me to significantly shorten my maintenance intervals. In other words, I did not add rear camber/toe adjusters to the rear because I don't want to frequently check my rear alignment (even if only because of paranoia.) Eccentric RTABs have the worst reputation out of the lot...

For me, subframe risers seem to be more manageable than any item that could potentially "come loose"


For "Part 1", I don't really understand your choice of solid RTABs, with 75A poly subframe (and I assume diff) mounts. If I were going to run solid anything, it would be the subframe/diff with softer RTABs.

I'm currently thinking about running Condor Speedshop Subframe riser bushings with the AKG 75D diff bushing I have now, with OEM RTABs, but that's just me.

[the imitator]

that's how mine are installed too, Solid raised condor subframe bushings, and akg 75D rtabs. I went for the condor diff bushing as well.

I don't really want to get involved in "Part 2" but for my car, which is a summer DD/autoX toy, I didn't want to add anything that causes me to significantly shorten my maintenance intervals. In other words, I did not add rear camber/toe adjusters to the rear because I don't want to frequently check my rear alignment (even if only because of paranoia.) Eccentric RTABs have the worst reputation out of the lot...

For me, subframe risers seem to be more manageable than any item that could potentially "come loose"


For "Part 1", I don't really understand your choice of solid RTABs, with 75A poly subframe (and I assume diff) mounts. If I were going to run solid anything, it would be the subframe/diff with softer RTABs.

I'm currently thinking about running Condor Speedshop Subframe riser bushings with the AKG 75D diff bushing I have now, with OEM RTABs, but that's just me.

[SkiFree]

Riser bushings are fine by themselves, but...

I know it's generally understood that they aren't a replacement for an adjustable setup (if you have a question about this, call akg, condor, or revshift and ask) ....

to underscore what Richard said about the absolute necessity to get a full amount of torque. An unfortunate consequence of using a riser bushing is that by pulling the subframe closer to the chassis there is considerably less clearance. Clearance that is essential to reach a wrench in there and torque down the adjuster. More than one time this leads to the inevitable loosening on the adjuster .... then it, the adjuster, gets blamed when it's loosening is a symptom of the greater issue of not enough torque.

In short, there have been a number of racers I know of who have switched from a riser mount BACK to a standard mount (from AKG, Condor, Ireland, Revshift, Walmart, etc) and thus being able to more easily get proper torque no longer have adjuster issues. I know multiple national championship winning cars running various adjusters and no riser bushings.

Now, that isn't to say that is the sole potential issue with adjusters but it is certainly one of the more prominent. (again, by calling some of those experienced race shops listed above, you mitigate the magnitude of misinformation rampant among message boards).

[Northern]

why would you even run subframe risers if you have adjustability?

[MatRacer]

Called IE today and talked with Andrew.

He told me that both serrated and eccentric could loosen if not properly tighten, but properly tighten, it was normally not an issue. Also, some teams lock wire them. He also mentioned that the serrated bolt was long enough to put a second nut to lock it up.

Its a pain to get access to it and great care must be deployed to properly tight it up.


A lot of valuable opinion here! Will push my thought further. Thanks!

[BraveUlysses]

How much do the riser bushings change the rear camber? i don't want to deal with adjustable rear suspension stuff