135i handling

[chris_flies]

Originally Posted by asiflicious

I don't mind the car getting lowered (not dumped) nor do I kind a harsh ride IF the pay off is worth it. If the car feels planted and ready to tear up some curvy roads I can live with less comfort

Well, I like my Koni's + Eibach Sport springs (30mm lowering). I got them from Tire Rack for around $800 to replace blown OE shocks (yes, original shocks with around 165k miles).

My car is just ready to pounce on a good back road, and the cloverleaf on/off ramps can be taken at very high speeds. I still have some M3 rear subframe bushings to install, but the Whiteline subframe bushing inserts that are in now are more than sufficient for enjoyable street driving.

I don't honestly know if coilovers are really worth it to you, unless you want your car REALLY low, or you regularly autocross/TT it and need the incremental performance increases. Also, they tend to be more expensive if that's a concern...

[asiflicious]

Originally Posted by chris_flies

Well, I like my Koni's + Eibach Sport springs (30mm lowering). I got them from Tire Rack for around $800 to replace blown OE shocks (yes, original shocks with around 165k miles).

My car is just ready to pounce on a good back road, and the cloverleaf on/off ramps can be taken at very high speeds. I still have some M3 rear subframe bushings to install, but the Whiteline subframe bushing inserts that are in now are more than sufficient for enjoyable street driving.

I don't honestly know if coilovers are really worth it to you, unless you want your car REALLY low, or you regularly autocross/TT it and need the incremental performance increases. Also, they tend to be more expensive if that's a concern...

I don't care about adjustability, I'm a set it and forget it kind of guy so coilovers would be a waste on me. How does high speed stability feel to you with your mods? Does it feel more stable over 100 than stock?

[chris_flies]

Originally Posted by asiflicious

I don't care about adjustability, I'm a set it and forget it kind of guy so coilovers would be a waste on me. How does high speed stability feel to you with your mods? Does it feel more stable over 100 than stock?

I have not gone 100 yet, but I have been at 75-80, though.

It's currently set (I do my own alignments with LAZERS and maths) to 0 toe all the way around, with about 2.7-2.8 degrees of negative camber at all four corners.

It tram-lines and bump steers a tad bit more than stock, but it's predictable and you can compensate easily. It does feel more stable than the stock alignment, and the steering has much better on-center feel and response than stock, it also feels less twitchy when the crown of the road changes, and it's not as tiring or fatiguing to drive now as it was stock on long drives (maybe I'm just a better driver than I was when it was stock).

[pablom2c]

I'm very happy with the handling difference the Bilstein B8 kit made on my car (it's the same as the B12 kit but without the Eibach springs), I kept the oem springs since I didn't want a drop in height. Handles much better, more planted, less body roll, better stability at high speed, less understeer and the floaty feeling is gone. I also put on OZ ultraleggera wheels which are lighter and wider (front 18x8 ET34 and rears 18X9 ET40).

I don't track or race my car, but I do drive spiritedly on the street and I'm very happy with the Bilstein B8. I would start with this (or other similar suspension kit) and non-runflat tires. Then see if you need the bushings, control arms, sway bars, lsd, etc.

You can read a similar thread about my car here:

http://www.1addicts.com/forums/showthread.php?t=1422741

[asiflicious]

Is there any difference between the B12 Pro Kit and Koni Yellow with Pro springs apart from brand name? Any performance/comfort/reliability differences between the two?

[Zombie_Head]

Originally Posted by BimmerAg

First of all, welcome! I'll try to address your points one-by-one the best I can:



The OEM runflats are known for being loud, expensive, not having great grip, and having a rough ride. Most people recommend replacing them as soon as you can, but I totally understand wanting to get the most out of your current tires first, and I think you can achieve the handling you want with other modifications.



In some other car scenes, coilovers are more of an aesthetic mod. Luckily from what I've seen on this forum, most members seem to be more focused on handling and performance and coilovers will 100% provide that if you get a QUALITY set. Blistein, Ohlins, Koni, KW, etc are all high quality sets, but can be closer to two thousand dollars. If you don't do very much track driving, then I'd recommend a spring and shock upgrade instead, preferably a matched set like this: https://www.turnermotorsport.com/p-1...nsion-package/
Koni also makes a kit with their yellow sport shocks and the same eibach springs. Be advised, both these kits will results in about a 1" drop. If you're not looking for that much of a drop, the BMW performance suspension (maybe 1/2" drop) is also very highly regarded, although it is more expensive: https://www.turnermotorsport.com/p-5...front-swaybar/



For a street car, LSD is definitely lower on the list, especially because of the high cost.



The rear subframe basically holds all the rear drivetrain parts. To connect the subframe to the main frame of the car, there are a few bolts with rubber bushings around them. These bushings help isolate some of the bumps and harshness from the road, but the stock bushings are very soft and can deflect under high loads, which makes the rear end feel unstable. The M3 bushing, is made of a stiffer rubber that doesn't deflect as much, and it gives the rear a much more planted feel, although it can come at the expense of slightly more NVH transmitted into the cabin. If you can do the work yourself, people say this is one of the best bang-for-the-buck upgrades you can do for your car's handling. also, I'd recommend using a 2-piece bushing for easier installation. Like this: http://www.whiteline.com.au/product_...=KDT917&sq=773

The M3/1M front control arms will help fight understeer by adding about .75° of negative camber. They also include stiffer bushings than the stock arms that will slightly firm up the front suspension.



Obviously, what mods are best will depend on what you want to do with the car, but it sounds to me like you want a better handling road car, not a track/autocross car. Based on that, I'd recommend the following top 3 mods:
1: Rear subframe bushing - one of the least expensive mods in your list (if you can do it yourself) and will really help plant the rear of the car
2: Spring/shock upgrade - This will make the biggest difference in how your car handles so make sure you go for a high quality kit. Stiffer springs will reduce body roll and firmer shocks will help get rid of the floaty feeling you're describing
3: Either new tires or M3 sway bar - With firmer suspension, you may feel like your car's ride has gotten rougher than you like. Luckily, non-runflat tires feel softer than the stock runflats and should get you back to a stock-like ride quality. If you don't mind the firmer ride, then the M3 sway bar is pretty cheap and will also reduce body roll.

Hope that helps! I'm also new to the 1 series, but I've been doing a lot of research lately and have pretty much decided to start with the same mods on my DD/weekend racer

Everything mentioned here is what i plan to do (slowly) to my 125i, starting with non RFTs and rear subframe bushings (since they make the biggest difference) then start tracking (for fun) and slowly upgrading the suspension, front control arms and then either a LSD or Software upgrade (we shall see).

Well covered sir.

[asiflicious]

Could someone link me to the RSFB inserts/ 2 piece bushings? I want to make sure I'm getting the correct parts. Also I've heard mixed feelings about these; are these good enough or should I just splurge and get the actual m3 bushings for significantly more?

[BimmerAg]

Originally Posted by asiflicious

Could someone link me to the RSFB inserts/ 2 piece bushings? I want to make sure I'm getting the correct parts. Also I've heard mixed feelings about these; are these good enough or should I just splurge and get the actual m3 bushings for significantly more?

Whiteline inserts: http://www.whiteline.com.au/product_..._number=KDT918

Whiteline 2-pc: http://www.whiteline.com.au/product_..._number=KDT917

[asiflicious]

Originally Posted by BimmerAg

Whiteline inserts: http://www.whiteline.com.au/product_..._number=KDT918

Whiteline 2-pc: http://www.whiteline.com.au/product_..._number=KDT917

What's the difference between the two, besides price? Are the 2 pieces better than the inserts?

[BimmerAg]

Originally Posted by asiflicious

What's the difference between the two, besides price? Are the 2 pieces better than the inserts?

I think the 2-pc bushings are comparable to the M3 ones in terms of stiffness/handling but easier to install with the 2-pc design.

The inserts give about 80% of the improvement from what I hear

[rowsdower]

Originally Posted by chris_flies

Well, I like my Koni's + Eibach Sport springs (30mm lowering). I got them from Tire Rack for around $800 to replace blown OE shocks (yes, original shocks with around 165k miles).

Koni streets or sports? I'm assuming Sports - the kit is $810 right now with a $70 rebate. I am strongly considering if I can convince my wife...

Remind me, do you also have M3 front arms? I know you have the Dinan camber plates.

[chris_flies]

Originally Posted by rowsdower

Koni streets or sports? I'm assuming Sports - the kit is $810 right now with a $70 rebate. I am strongly considering if I can convince my wife...

Remind me, do you also have M3 front arms? I know you have the Dinan camber plates.

I have all the arms, but I'm not all arms

Yes, they are sports. My build thread is linked in my signature, everything about my car is in there, along with my thoughts on each mod...

[asiflicious]

Originally Posted by BimmerAg

I think the 2-pc bushings are comparable to the M3 ones in terms of stiffness/handling but easier to install with the 2-pc design.

The inserts give about 80% of the improvement from what I hear

Do you need the special subframe bushing tool to install the 2 piece bushings?

[fast1eddy]

Bimmerag pretty much nailed it. Don't overthink it. Bmwperformance suspension with Whiteline 2 piece RSFBs will get you 90% there. The kit comes with a sway bar so the M3 bar is a negligible upgrade. Never had runflats on my car but I can't see them being a detriment to handling. Ride yes but not handling.
I have the BMW performance suspension on my car along with the Whiteline bushings and they both made an equally impressive improvement to the handling of my car. I'm adding the M3 arms front and rear now just to get that last little bit of precision I want. Not a necessary upgrade but once you start with upgrades it hard to stop.

[fast1eddy]

Originally Posted by asiflicious

Do you need the special subframe bushing tool to install the 2 piece bushings?

You don't need a special tool at all to install the 2 piece. To get the stock ones out I used the heat method. Was a real pain in the ass. I think ecs tuning has a tool you can buy. Well worth the investment.

[Gangplank]

M3 front control arms
RSFB inserts or 2 piece bushings
Differential lockdown bracket (got mine from 135droptop through the classifieds)

Those 3 things really did a great job of improving the handling. From soft & uneasy to responsive. The Ohlins R&T made it FAR better still. ;-)