Dinan Stage 2 Suspension

[Dave2]

I have decided to get the Dinan Stage 2 suspension for my 2011 E93. I am considering doing the installation myself. Even though I have not done any major work on a car in a few years I have years of automotive and mechanical experience and access to all the necessary tools.

Has anyone done this installation as a DIY? Are there any lessons learned, tricks or tips you could pass along? Or having done the DIY wishing you would have had a professional do it?

Thanks

[kitw]

Why stage 2? The front bar will just make the car understeer more. Stick with stage 1 or get the Stage 3 with the camber plates.

[paradocs98]

Also keep in mind that this is something like an 8-hour install for a professional mechanic, so be prepared for a significant amount of time...

[Sleeper519]

If I recall correctly, Stage 2 is the Dinan springs, plus the thicker front sway bar from the E93, which you already have on your vert...

I would get Stage 1, plus Ground-Control adjustable camber plates.

[cole328]

Hmmm...I went with the Stage 2, and I don't notice any appreciable understeer at all car is super nimble, the "drop" was perfect for me, and it's flat as the top of a cop's head in the turns
However, I'm not tracking the car at all, so perhaps you should listen to the more experienced guys on here

[Sleeper519]

How can Dinan sell you an expensive stage 2 kit for an E93 that has a front sway bar that is the exact same size (28.5mm) as the stock one that is already on the car??

Unless it's a larger diameter than they're advertising on the website, that's fraud.

[bigjae1976]

Originally Posted by Sleeper519

How can Dinan sell you an expensive stage 2 kit for an E93 that has a front sway bar that is the exact same size (28.5mm) as the stock one that is already on the car??

Unless it's a larger diameter than they're advertising on the website, that's fraud.

It's not the same bar. The E93 bars are 28.5 on the ends but thinner across the rest of the bar.

[Dave2]

Originally Posted by cole328

Hmmm...I went with the Stage 2, and I don't notice any appreciable understeer at all car is super nimble, the "drop" was perfect for me, and it's flat as the top of a cop's head in the turns
However, I'm not tracking the car at all, so perhaps you should listen to the more experienced guys on here

Thanks for the input. This car is a daily driver in all weather conditions. 75% of the time it is driven in commuter mode the other 25% I drive it like I stole it. I have no plans to track the car. Based upon your results it sounds as though the Stage 2 is the correct choice for me.


Still looking for advice from anyone that has done a DYI installation.

[Mbauer]

I suggest doing it on a lift atleast. Im not sure if you have a spring compressor??? Took me 4 hrs but I do this for a living.

[Sleeper519]

Originally Posted by bigjae1976

It's not the same bar. The E93 bars are 28.5 on the ends but thinner across the rest of the bar.

Thanks for that info. I can climb down quietly from my soapbox now...

[Dave2]

Originally Posted by Mbauer

I suggest doing it on a lift atleast. Im not sure if you have a spring compressor??? Took me 4 hrs but I do this for a living.

I have access to the whole magila; lift, spring compressors, air tools, alignment rack. 4 hours seems like a more realistic estimate. 8 hours seems excessive. Are there any tricks or tips you could impart after having done the install? What alignment numbers did you use?

[Denk]

Dinan includes recommended street and track alignment specs with his kits.
Stage 1 and 2 street specs are the same, stage 3 has a little more neg camber front and rear. I can't remember the numbers though. Good luck, I'm sure you'll love the results.

[Dave2]

Thanks guys. Just place the order and looking forward to getting to work on this soon.

[kitw]

Originally Posted by bigjae1976

It's not the same bar. The E93 bars are 28.5 on the ends but thinner across the rest of the bar.

I can confirm... the Dinan front bar is solid (or significantly thicker wall) as well. It's really friggin heavy compared to stock and much beefier than the E93 bar.

But... the car already understeers, I'm not sure why you want to increase that.

If you aren't feeling it, you aren't pushing the car...

[Dave2]

Originally Posted by kitw

I can confirm... the Dinan front bar is solid (or significantly thicker wall) as well. It's really friggin heavy compared to stock and much beefier than the E93 bar.

But... the car already understeers, I'm not sure why you want to increase that.

If you aren't feeling it, you aren't pushing the car...

Why are you under the impression that a stiffer sway bar increases understeer? The stiffer bar reduces body roll. The reduction in body roll reduces weight transfer to the outside wheels during a turn, which in turn tends to equalizes the traction between all tires. This results in less understeer.

If we were to follow the line of logic that a stiffer bar increases understeer, then the logical conclusion would be to simply remove the sway bars to eliminate understeer. I think you imagine what would happen in that case. As you made a turn the body of the car would roll over as it wanted to continue in a straight line (an object in motion will tend to stay in motion, in a straight line, until acted on by an outside force- Isaac Newton) leading to obscene understeer.

[bigjae1976]

Originally Posted by Sleeper519

Thanks for that info. I can climb down quietly from my soapbox now...

No problem...asked the same question and did tons of research...just to throw you off your soap box.

IMO, the more I think about it, the closer I come to the conclusion that the camber plates are a waste.

[klammer]

Have to agree with kitw on the understeer thing, but can't be bothered to explain. On another note, car really handles great on the street and feels nimble and tight, only on track do you really see the weight and understeer problems with this car. Think you'll love the setup.

[Z K]

Originally Posted by Dave IV

Why are you under the impression that a stiffer sway bar increases understeer? The stiffer bar reduces body roll. The reduction in body roll reduces weight transfer to the outside wheels during a turn, which in turn tends to equalizes the traction between all tires. This results in less understeer.

If we were to follow the line of logic that a stiffer bar increases understeer, then the logical conclusion would be to simply remove the sway bars to eliminate understeer. I think you imagine what would happen in that case. As you made a turn the body of the car would roll over as it wanted to continue in a straight line (an object in motion will tend to stay in motion, in a straight line, until acted on by an outside force- Isaac Newton) leading to obscene understeer.

A sway bar (aka anti-sway bar aka stabilizer bar) causes the inside wheel to lose grip as cornering load is applied to the outside wheel. It connects both sides so it reduces independent suspension movement.

With a rear sway bar, it makes the car more tail happy because as you corner, the outside wheel is pushed upward which pushes the inside wheel upward through the sway bar which connects both sides. It causes both to take load and lose grip easier.

A front sway bar makes the front give out faster than the rear. It helps turn in as the front feels sharper as the inside and the outside react the same but after initial turn in, it causes the front the understeer as the load on the outside wheel pushes the inside wheel to lose traction as well so both front wheels are pushed upward and you lose front grip.

So generally a front sway bar feels stable at turn in but causes understeer, a rear sway bar causes oversteer... sway bars are sometimes sold in sets so you get the best of both worlds.

[shendrick]

Increasing roll stiffness up front (stiffer front bar) means the inside front wheel will unweight more in turns increasing understeer.

[Dave2]

Originally Posted by Z K

A sway bar (aka anti-sway bar aka stabilizer bar) causes the inside wheel to lose grip as cornering load is applied to the outside wheel. It connects both sides so it reduces independent suspension movement.

With a rear sway bar, it makes the car more tail happy because as you corner, the outside wheel is pushed upward which pushes the inside wheel upward through the sway bar which connects both sides. It causes both to take load and lose grip easier.

A front sway bar makes the front give out faster than the rear. It helps turn in as the front feels sharper as the inside and the outside react the same but after initial turn in, it causes the front the understeer as the load on the outside wheel pushes the inside wheel to lose traction as well so both front wheels are pushed upward and you lose front grip.

So generally a front sway bar feels stable at turn in but causes understeer, a rear sway bar causes oversteer... sway bars are sometimes sold in sets so you get the best of both worlds.

This may be true of a car with a double wishbone suspension where the camber angle remains consistent through the range of suspension travel.

It is not true with strut-type suspensions, as is the BMW's, where the camber angle changes through the range of suspension travel. With a strut suspension camber becomes more negative as the suspension begins to compress. As the suspension continues to compress the camber becomes more positive. The stiffer front bar will limit the suspension compression and maintain the more negative camber angle.

[Dave2]

Looks like my son will be getting a freebie. He has a 135i and it seems the 135 guys are replacing their front sways with the E93 M3 sway bar. So, when i get my Dinan he can have mine. He will be picking up the lunch tab.

[Dave2]

The Stage 2 kit has arrived. Installation is scheduled for Monday.