[cu260r6]

I recently posted to determine if M4 springs were compatible with my F32 xdrive, and no one knew the answer. I just did the conversion and thought others could appreciate my findings.

The M4/M3 F82/F80 springs worked perfectly on my 428i xdrive. I just installed them with koni special active dampers without any fitment issues. I tried to install spacers to prevent any drop, but the ones I had did not fit. However, the drop was still modest at .5in, so I was not deterred.

M4 springs are about 20% stiffer than stock F30/F32 and seem to offer the perfect setup for my daily driver. The ride is much better over smaller bumps and seams with the konis and the springs allow me to take larger bumps with a bit more speed without fear of scraping my bumper. Body roll is significantly reduced, and there is no harshness.

[cfm56d7b]

Incidentally, do you know if M3/M4 springs are progressive?

PS. Nice R&D project.

[Logicoeur]

How would spacers affect the drop? They only move the tires outward and I would like to believe you don't want the fender putting it's weight on top of the tire. That would rip them out.

[cu260r6]

Originally Posted by Logicoeur

How would spacers affect the drop? They only move the tires outward and I would like to believe you don't want the fender putting it's weight on top of the tire. That would rip them out.

Spring spacers, not wheels spacers. Something like this: https://www.jegs.com/i/JEGS/555/60828/10002/-1

[cu260r6]

Originally Posted by cfm56d7b

Incidentally, do you know if M3/M4 springs are progressive?

PS. Nice R&D project.

Huh, didn't consider they could be beforehand actually. They certainly do not feel like they are when driving, and the appearance of the coils do not look similar to other progressive springs I've seen.

[FaRKle!]

Originally Posted by cu260r6

Spring spacers, not wheels spacers. Something like this: https://www.jegs.com/i/JEGS/555/60828/10002/-1

Did you try the ones that are supposed to go between the coils rather than on top/bottom like the one you linked?

[thakid22]

Originally Posted by cu260r6

I recently posted to determine if M4 springs were compatible with my F32 xdrive, and no one knew the answer. I just did the conversion and thought others could appreciate my findings.

The M4/M3 F82/F80 springs worked perfectly on my 428i xdrive. I just installed them with koni special active dampers without any fitment issues. I tried to install spacers to prevent any drop, but the ones I had did not fit. However, the drop was still modest at .5in, so I was not deterred.

M4 springs are about 20% stiffer than stock F30/F32 and seem to offer the perfect setup for my daily driver. The ride is much better over smaller bumps and seams with the konis and allows me to take larger bumps with a bit more speed without fear of scraping my bumper. Body roll is significantly reduced, and there is no harshness.

How do you rate the bounce with this combo?
Is it less bouncy than stock? Whichever end bounces more while driving, the front or the rear?

[cu260r6]

Originally Posted by thakid22

How do you rate the bounce with this combo?
Is it less bouncy than stock? Whichever end bounces more while driving, the front or the rear?

The dampening is spot on for these springs, more controlled than stock and there is no double rebound bounce you see from those that have stiff springs on stock shocks.

It was a total guess which shocks would match these springs best, but I am very happy with the choice. The Koni FSD/Special Active are OEM for Lamborghini so I hoped they would work well with the M3/4 springs which are only about 20% stiffer.

Before this, I had a 128i with Koni Str.t shocks and pretty stiff Megan lowering springs. There was not nearly enough dampening to keep up with the spring rate on that car. These Special Actives are a far better match.

[cu260r6]

Originally Posted by FaRKle!

Did you try the ones that are supposed to go between the coils rather than on top/bottom like the one you linked?

No, I don't think those would have worked since my understanding is they are for a dual spring setup on coilovers. I wish I could have found a perfect set of spacers, but I didn't have the time to find other parts. The car is still high enough for a daily driver living in the mountains in CO and dealing with winter driving.

[FaRKle!]

Originally Posted by cu260r6

No, I don't think those would have worked since my understanding is they are for a dual spring setup on coilovers. I wish I could have found a perfect set of spacers, but I didn't have the time to find other parts. The car is still high enough for a daily driver living in the mountains in CO and dealing with winter driving.

They work for these springs. See my experience with them.

[cu260r6]

Ahh, gotcha now. I didn't use those because they reportedly stiffen the spring rate, and preventing that was a large reason I tried this setup instead of Eibach sports.

Did you notice a difference in ride with yours installed?

[Z K]

Do you have any pictures of your set up?

Since your car is a 428i X Drive and it dropped your car 1/2 an inch - that means if someone runs the same set up on a RWD Sport suspension car (10mm lower than non Sport), it should lower the car 10mm or so?

[Eschmacher]

So I bet this would mean I could theoretically put f80 springs on my f30 right? I'm thinking about going with lowering springs with my adaptive suspension.

[cu260r6]

Absolutely. They fit perfectly.

[Z K]

I have a set of F80 springs that I will be installing on my RWD 328i.

The F80 and F82 rear springs are different. The F80 has a lower cut rear fender. If you fit F82 rear springs on a F80, it will cause the rear to be much lower and vice versa.

[FaRKle!]

Originally Posted by Z K

I have a set of F80 springs that I will be installing on my RWD 328i.

The F80 and F82 rear springs are different. The F80 has a lower cut rear fender. If you fit F82 rear springs on a F80, it will cause the rear to be much lower and vice versa.

I don't believe that's true. I do recall that the F80/82 rear spring is different whether the car was optioned with sun/moonroof or not though. Likewise, the front springs are different depending on if the car was optioned with DCT or manual.

For your setup I'd want to try the manual transmission front spring first, since you have less weight in the front than an F80 (4cyl vs 6cyl engine), thus your ride height will probably be higher than the F80.

Interestingly, the 4cyl engine weights + xDrive components (transfer case and axles) brings the front weight pretty close to that of an F80 from my calculations

[Z K]

Originally Posted by FaRKle!

I don't believe that's true. I do recall that the F80/82 rear spring is different whether the car was optioned with sun/moonroof or not though. Likewise, the front springs are different depending on if the car was optioned with DCT or manual.

For your setup I'd want to try the manual transmission front spring first, since you have less weight in the front than an F80 (4cyl vs 6cyl engine), thus your ride height will probably be higher than the F80.

Interestingly, the 4cyl engine weights + xDrive components (transfer case and axles) brings the front weight pretty close to that of an F80 from my calculations

For the F80 and F82, most lowering spring companies have different springs that are specific for the sedan or the coupe. The rear height is different if you switch springs from sedan and coupe.

Is there a spring code listing for F80 springs? Something that can convert the 2 letter spring code? I know the springs I have is from an F80 but I don't know which car it is from. Most likely it is a DCT car as most cars sold were DCT.

[FaRKle!]

Originally Posted by Z K

For the F80 and F82, most lowering spring companies have different springs that are specific for the sedan or the coupe. The rear height is different if you switch springs from sedan and coupe.

Is there a spring code listing for F80 springs? Something that can convert the 2 letter spring code? I know the springs I have is from an F80 but I don't know which car it is from. Most likely it is a DCT car as most cars sold were DCT.

The 2-letter code on the spring barcode denotes which PN they are, but you need to know which letter code matches with what PN. I tried seeing if there was any info in the barcode itself (such as the PN), but didn't come up with anything using a phone barcode reader app.

[cfm56d7b]

Rethinking future suspension upgrade and looking for recommendations for my 2017 BMW 440i GC RWD with EDC suspension:

- Shocks: Bilstein B6 Damptronic shocks https://www.bimmerworld.com/Bilstein...2-F3X-RWD.html

The description indicates " ... suitable for cars with stock coil springs".

- Would M4 springs be compatible with my vehicle? My goal is to maintain OEM ride height as much as possible.

[FaRKle!]

Originally Posted by cfm56d7b

Rethinking future suspension upgrade and looking for recommendations for my 2017 BMW 440i GC RWD with EDC suspension:

- Shocks: Bilstein B6 Damptronic shocks https://www.bimmerworld.com/Bilstein...2-F3X-RWD.html

The description indicates " ... suitable for cars with stock coil springs".

- Would M4 springs be compatible with my vehicle? My goal is to maintain OEM ride height as much as possible.

The springs will fit/are compatible. The GC rear is a bit heavier, so you may want a spacer/shim for ride height.

The M3/M4 base suspension springs are about 5-7% stiffer front and rear over your OE springs. Not a huge change. Are you looking for much stiffer?

[cfm56d7b]

@FaRKle!, thank for responding.

I find OEM springs to be "flat" - for the lack of a better word - in how they respond to road imperfections.

I sense OEM springs are linear va progressive. Do you know by any chance if that's the case?

[FaRKle!]

Originally Posted by cfm56d7b

@FaRKle!, thank for responding.

I find OEM springs to be "flat" - for the lack of a better word - in how they respond to road imperfections.

I sense OEM springs are linear va progressive. Do you know by any chance if that's the case?

The OE springs are indeed linear. The M2, and M3/4 competition pack rear springs are progressive though.