[BMR Tech]

Fortunately, yet unfortunately we have been so swamped here at BMR - I have had a hard time keeping up with some things. One of those "things" happens to be providing you 6th Gen owners with good data.



I often get asked "what arms do I need for this" - or "If I do your toe rods, do I need trailing arms and upper arms or?"

The good news is - GM didn't just hit a homerun on this IRS System, they hit a Grand Slam!



First let's look at GM's recommended alignment specs for the SS-FE3:

STREET:
Front Camber
-.75 Degrees (+/-.8 Degrees)

Front Toe
.2 Degrees (+/- .2 Degrees)

Rear Camber
-.9 Degrees (+/- .8 Degrees)

Rear Toe
.2 Degrees (+/- .2 Degrees)

TRACK:
Front Camber
-1.5 Degrees (+/-.15 Degrees)

Front Toe
.1 Degrees (+/- .05 Degrees)

Rear Camber
-1.25 Degrees (+/- .15 Degrees)

Rear Toe
.1 Degrees (+/- .05 Degrees)



So now that we know what GM calls for, let's have a look at a 2016 SS and it's OEM Rear IRS Camber, and curve when dropping it down lower than stock height with a coilover kit or lowering spring, etc.

The graph/bars start at stock ride height, which is set to -.8 Camber.



As you will notice, dropping the rear of the car approximately 1.00" in the rear without touching camber adjustment, puts the car right on the upper spec of "TRACK" camber settings. Of course, every car and set of results can differ...but for us, this holds true.

The good news is:

-we did not see any realistic drop amount cause an issue with the OEM Adjustment offerings. (lower arm and Toe Link)

-the OEM adjustment will support approximately a 2.75" rear drop...which we do NOT recommend for geometry purposes

-we do not see a "need" in terms of alignment spec, to acquire an aftermarket kit or components for the rear IRS.

-GM improved the geometry over the previous 5th Gen IRS system, as the "need" to acquire supporting adjustable pieces is simply not the case.

Now with that said, we do agree here at BMR that when lowering the car, the BMR Toe Links make precise and proper adjustment MUCH MUCH easier and simplified. The person performing the alignment will definitely prefer our adjustment method/style over the OEM. Getting it "just right" is rather tedious.

We also prefer the lock out plates with our Toe Link kit. This allows you to solely rely on the adjustment of the Toe Link Bar....and not have an issue with toe slip and the need to re-align the car after putting it through it's paces.

I will be adding to this thread as time goes. If you have any questions for me, please do not hesitate to ask!

[Tr6]

Thank YOU for the FANTASTIC info!

[BradfordCamaro]

Awsome.
....errr...Did you just tell us we don't have to buy your products. Hahaha

Honest and open. What a Great Company.

[SS 1LE]

Great information.

[crankaholic]

Originally Posted by BradfordCamaro

Awsome.
....errr...Did you just tell us we don't have to buy your products. Hahaha

Honest and open. What a Great Company.

Not for alignment purposes. Upgraded suspension components will greatly decrease deflection and improve feel. I do agree it's awesome that BMR are being honest and open about things

[PolynesianPowerhouse]

Have you any pics of the lockout plates?

[nbryant]

Excellent data, thanks!

[BMR Tech]

Originally Posted by PolynesianPowerhouse

Have you any pics of the lockout plates?

[diirk]

This is great information. Thanks.
I was just looking at the specs and determining what I want to accomplish with my alignment.

I tend to lean towards the performance end of the street settings. I'm considering the following:

Front Camber
-1.25 Degrees
Front Toe
.05 Degrees
Rear Camber
-1.0 Degrees
Rear Toe
.1 Degrees

I tend to think the steering in this car is slow and heavy so want to lighten that up a bit. My usual recreation is the occasional canyon run, hence the higher end of the neg. camber.

am I on the right track with these numbers?

[diirk]

Well, here's what I ended up with for an alignment.

Front Camber: -1.25
Front Toe: 0.0
Rear Camber: -0.50
Rear Toe-In: .12 / side

Turn-in is improved. Handling is good. Haven't had a chance to run it through the canyons yet.

[Mountain]

Originally Posted by diirk

Well, here's what I ended up with for an alignment.

Front Camber: -1.25
Front Toe: 0.0
Rear Camber: -0.50
Rear Toe-In: .12 / side

Turn-in is improved. Handling is good. Haven't had a chance to run it through the canyons yet.

I'm curious where your car was from the factory.

I'm going to get a performance (autcross FS) directed alignment here pretty soon. This is what I was going to shoot for:

Front
Camber: -2.0 to -1.5 (hoping to get as close to -2.0 as possible, but max negative and equal L/R is the main goal)
Toe: 0.0
Caster: 7.2-ish (anything more than 6 is fine in my experience with MacPherson setups; as long as it's near equal L/R)

Rear
(going to leave wherever factory is now at for a while, but hoping for...)
Camber: -1.0-ish
Toe: 0.1 (just want a tiny bit positive for high-speed stability)

[bubbajan21]

I see you posted the GM street and track alignment specs, but what does BMR recommend to get the most out of a street car?

[Daves1SS]

I put the BMR springs on my '16 SS this weekend, and just this morning had pep boys auto do the alignment. Even though they put it in their system on the main paperwork as a 2016 model as I told them it was, now when looking at the alignment sheet they did it for a 2013-2015 Camaro SS which has a totally different chassis. :-( so I guess I should take it back to them since the 2016 has different specs?

[diirk]

Originally Posted by Mountain

I'm curious where your car was from the factory.

I don't have a reference from the factory. I installed springs and then realigned.