Suspension refresh - critique my life choices

[bigjae46]

If you already have the RTAB tool, it obviously works on the RTAB, but also for removing the subframe bushes.

For everything else, I mostly use some Chinese kit with threaded rods and cups, you can find it on Amazon if you type "26pc bushing tool".
There are loads of sellers selling it, just opt for the cheapest one since they are all the same.

I recently purchased a nice press, a great addition to my home workshop, so I'll mostly be using that from now on, albeit still with the cups from the Amazon tool mentioned above.

Yeah, I think it was a Vevor kit? It removed the outer ball joints with ease. The pain in the ass ones are the inner upper control arm bushing and the subframe bushings.

[tlow98]

If you use the official bmw tool or a knock off of it the subframe bushing are very easy.

theres a cheaper version of this out there somewhere. Find it. You’ll be happy you did.

https://www.fcpeuro.com/products/bmw-subframe-mount-tool-kit-baum-b334150?ads_cmpid=1586640911&ads_adid=59893888775&ads_matchtype=&ads_network=g&ads_creative=298302526031&utm_term=&ads_targetid=pla-320252258155&utm_campaign=&utm_source=adwords&utm_medium=ppc&ttv=2&gclid=Cj0KCQjwldKmBhCCARIsAP-0rfzPUCzEPEjI7VjAHzBoaGQsCuCEo23-WbZAR1WCdx2mzioNQWjQ9sUaAijfEALw_wcB

[Nate047]

Thanks guys, this is much more helpful than the "use a torch and a hammer" response I got on facebook lol.

[tlow98]

Thanks guys, this is much more helpful than the "use a torch and a hammer" response I got on facebook lol.

After using the tool. You’ll be amazed. It’s made to be done with the subframe in the car, believe it or not. When it’s outside the car you can do all 4 in under an hour once you get it down.

Any other way will be A struggle and you’ll risk marring something or potentially ruining a part.

[Casa de Mesa]

I have the Bavarian Motorsports one. It's very similar to the BMW one, nearly identical. Agree with tlow98 absolutely worth the cash dollah billz.

[Nate047]

Right on guys, how do we feel about this one?

https://www.amazon.com/dp/B07SQTB4JB?psc=1&ref=ppx_yo2ov_dt_b_product_details

I haven't had time to start on anything yet. I have the weekend free, so hopefully I can get the headliner done at the very least. I have this sort of inexplicable nervous/anxious feeling, I have to just get over that and start doing stuff a little bit at a time.

[cornerbalanced]

And very few of them (if any) are OE bolt-in cages. Its your head - your choice.

I don’t understand your argument. It’s unsafe to drive a fully caged car on the street for obvious reasons, people have died from low speed accidents in fully caged cars from hitting their head too hard on the unpadded cage itself. This logic doesn’t apply to cars with half cages/roll bars however.

Are you saying it’s unsafe for any car to be driven on the street with a roll bar? In which case I would suggest cars that came with roll bars from the factory that were intended for street use (M4 GTS, M3 GTS, numerous Porsches,…) OR, are you positing it’s simply impossible for an after market manufacturer to develop a roll bar as safe as OE manufactures—something I would also be in disagreement with.

Nate—your list looks great. I wouldn’t change much. Worth looking into geometry correcting offset bushings for the rear suspension…trailing arm cars don’t react well to being lowered. MK Rennsport sells a good kit to correct rear geometry. Someone also mentioned adjustable tie rod ends for bump steer correction.

[01SG]

I don’t understand your argument. It’s unsafe to drive a fully caged car on the street for obvious reasons, people have died from low speed accidents in fully caged cars from hitting their head too hard on the unpadded cage itself. This logic doesn’t apply to cars with half cages/roll bars however.

Are you saying it’s unsafe for any car to be driven on the street with a roll bar? In which case I would suggest cars that came with roll bars from the factory that were intended for street use (M4 GTS, M3 GTS, numerous Porsches,…) OR, are you positing it’s simply impossible for an after market manufacturer to develop a roll bar as safe as OE manufactures—something I would also be in disagreement with.

See my post about seat backs collapsing in particular. And for the record, the GT3 does not have roll bars in America because of "American safety regulations prohibiting anything in the vehicle's cabin from housing non-deformable objects."

I don't know how BMW got away with it, but nevertheless, neither the GTS nor GT3 are really street cars. There is no reason to drive them on the road except to show them off or go to the track. They do have fixed back seats, at least, but in an intense enough accident, they are still absolutely dangerous.

[bigjae46]

See my post about seat backs collapsing in particular. And for the record, the GT3 does not have roll bars in America because of "American safety regulations prohibiting anything in the vehicle's cabin from housing non-deformable objects."

I don't know how BMW got away with it, but nevertheless, neither the GTS nor GT3 are really street cars. There is no reason to drive them on the road except to show them off or go to the track. They do have fixed back seats, at least, but in an intense enough accident, they are still absolutely dangerous.

The GTS had fixed back seats AND 6pt harness IIRC. I'd guess that the GT3 is the same.

@cornerbalanced

The OEM safety system is designed much differently to a racing car system in that the OE system has to be convenient to live with. The OE system has to allow movement. If you see the video below the driver's head was all the way over to the passenger seat. Factor in steel bars and the forces involved in an accident then you start seeing the risk involved with adding a roll bar to a street car. In most street accidents you typically have no time to mitigate the impact.

While the aftermarket can try and engineer a roll bar safe for the street I highly doubt they have the resources to take all of the variables into account AND sell enough units to make a profit. So what you see are a bunch of products which are "engineered" to be a roll bar or harness bar. It really comes down to your personal tolerance for risk.

I'd say a roll bar is fine on a car that's rarely driven on the street. Some are willing to DD a car like that.

As with any safety system we put together for a track car - understand the compromises! I see stripped out cars with no airbags and no window nets - that's a compromise! Me included...I am aware of the risk but I probably should just put the damned window net up.

https://youtu.be/G-QVOo8H_pQ

[karter16]

After using the tool. You’ll be amazed. It’s made to be done with the subframe in the car, believe it or not. When it’s outside the car you can do all 4 in under an hour once you get it down.

Any other way will be A struggle and you’ll risk marring something or potentially ruining a part.

Completely agree - have done this job without the right tools. We ended up manufacturing our own to get the job done, but if I was doing this again I'd just stump up for the right tools for the job.

[Nate047]

I bought the tool from Amazon I linked above, looks good. I guess I won't really know until I try to use it but I feel like it will work. I won't have time to do anything on the car for a couple weeks probably, but I did order some more stuff. I *believe* I now have everything I need.

I went with a Turner bump steer kit, and I bought some offset RTAB bearings from Millway. The MK kit mentioned above is nice but costs about double because it includes the RTAB. I don't need or want to buy yet another set of RTAB. I have CMP ones and those should will work well with the offset bearings. I also bought some dust boots for my rear LCAs.

I also decided to go with a set of Brey Krause direct to floor seat mounts. If not having the ability to slide the seat becomes a problem, I will rethink that. But I think it should be fine. No one else will drive the car except me pretty much ever. I am considering the seat back braces as well, I feel like more than likely I will do those because it seems contradictory to do fixed seat mounts and not brace the backs as well. If I have any money left and if my wife doesn't murder me, I'll be looking at a steering wheel, boss, and shifter too.

I appreciate the conversation about the roll bar, I did after all, ask you to critique my life choices. I will indeed be running the bar, and like I mentioned I will also be putting pads on it. I am comfortable with that personally, and I do understand the arguments against doing the bar for a road car.

[bigjae46]

I appreciate the conversation about the roll bar, I did after all, ask you to critique my life choices. I will indeed be running the bar, and like I mentioned I will also be putting pads on it. I am comfortable with that personally, and I do understand the arguments against doing the bar for a road car.

You'll be fine as long as you understand the potential issues. Everyone does something that has a compromise when modifying their car.

[Nate047]

Alrighty so I ended up getting a set of eccentric rear control arm bushings from Millway.

There seem to be 3 kits like this from what I've seen, MK Rennsport, Custom Racetec, and Millway. If anyone knows of others, please share.

MK and Custom Racetec both have 3 piece kits which include an eccentric offset RTAB, where as Millway only offers a two piece kit, and additionally only sells a centered RTAB.

What would be the reasoning behind these two different approaches? Centered RTAB vs eccentric offset, when paired with eccentric offset rear control arm bushings?

https://www.millway.se/eccentric-control-arm-bushing-bmw-e36-e46-z4-m3.html

(also weird that their photo shows one which looks like its installed upside down?)

https://www.mk-motorsportteile.de/p/bumpsteer-sturz-und-rollzentrums-korrekturkit-ha-e36-e46-wtcc

https://www.youtube.com/watch?v=cxLs6wOhOZ8&list=PLhjyHZurci87qgsOGxqyYCv4xKK6AxSm-&index=8

Here is the Custom Racetec kit, start at about 1 minute in and you can see the kit installed

[9kracing]

I was eyeing MKs tie rod ends last night funny enough lol, thought of this thread

[Nate047]

I was eyeing MKs tie rod ends last night funny enough lol, thought of this thread

Yea but for 440 euros, I dunno. I bought the Turner Motorsports kit for less than 300 US shipped, because they now offer lifetime replacement warranty. Thought that was a good consumable to try and get free replacements on.

This was the response from Millway regarding eccentric offset vs centered on the RTAB:

Hi Nate. Thanks for your reminder.
When a bushing are mounted in the subframe och hub, an eccentric bushing will change the geometry, rollcentre etc.
When a bushing are mounted in the control arm it will only change the length not the position where the bushing pivots.

The bushing always pivot around the bolt. So if you change the RTAB to an eccentric on a E36/E46! Where are the bolt? Exactly on the same spot regardless of how the bushing are designed.

It is common that people make eccentric bushings everywhere without really understand the purpose.

However there is one reason you can have eccentric RTAB. If you want to move the wheelbase for wheel clearance purpose. But then you have to install them 90 degrees difference what most people do.

I hope you understand what I mean. Otherwise let me know.


Best Regards
Samuel Lindkvist
Millway Motorsport