I've been crawling around in parking lots and dealerships, looking under every RWD Hyundai/Kia product I can find, taking measurements when possible. This has included my 09 Genesis Coupe, a dozen first generation Genesis Sedans, a new G70, a couple Kia Stingers, a Kia K9, a 2015 Equus and a GV80 Luxury SUV-thingy.
Here's what I've found to be consistently true:
1. The overall suspension geometry in the rear appears to be universal. It's all five link with the spring mounted on the rearmost lower control arm. The subframes, however, mount to the chassis in slightly different ways depending on application.
2. The rear knuckles appear to swap universally.
3. The lower half of the front suspensions appears to be universal in geometry and dimensions. Interestingly, the floofy luxury applications (Equus, Genesis Sedan, K9, SUV dealy) all have a multi-link top half of the front suspension while the sporty applications (Gen Coupe, Stinger, G70) are all McStruts. Not sure what to make of this.
This is aluminum rear knuckle version 1, off an Equus.
Here's aluminum knuckle version 2, off a Genesis sedan.
Here's the iron knuckle.
Here's what I've found to be inconsistent and confusing:
1. In the context of the five link rear suspension, I've found aluminum and iron versions of the spring-mounting lower rear control arm, the lower front control arm, the upper front control arm and two aluminum versions on one iron version of the knuckle. However, I've literally never found the same combination of parts on any two cars. The amount of aluminum that ends up in the rear suspension appears to be almost completely random.
I've found a first generation Genesis sedan that was 100% iron, another one that had an aluminum upper top control arm and an aluminum knuckle but iron everything else, another that had an aluminum spring-mount control arm, an iron knuckle and an aluminum forward lower control arm. The Stinger was 100% iron except for the knuckle. The G70 was entirely iron. The SUV thingy had an aluminum spring mounting lower control arm, an iron lower trailing arm, an aluminum knuckle and iron upper control arms. My Genesis Coupe is 100% iron as well.
2. The amount of aluminum in the front suspension is not quite as random, but it's close. All the multilink cars have iron uppers and aluminum knuckles. This is consistent. Most but not all of the luxury applications have aluminum lower control arms. I've seen Genesis Sedans both with and without aluminum lower control arms. The Equus was all aluminum, as was the SUV thingy. The K9 was iron in the front control arm and aluminum on the rear. The Stinger, G70 and Genesis Coupe, ie the strut cars, are all iron.
So, if my logic is sound to this point, there are aluminum versions of the following things:
Rear knuckles (two versions).
Spring mounting lower control arm in the rear suspension.
The front lower control arm in the rear suspension.
The upper front control arm in the rear suspension.
Everything in the bottom half of the front suspension.
However, which of these parts will end up on which car seems almost random. Is there anyone skilled in parts-catalogue-fu who can help me with part numbers or application guides?
