M3 endlink conversion on 325is question

[Maybe Magpie]

Question up front; with IS red-dot springs (basically M3 springs but one coil taller to my understanding) and the retrofit aftermarket M3-style endlink tabs welded onto my strut housings, would I have any issues running stock-type M3 swaybar endlinks?

After my upcoming MT swap my next thing to tackle is suspension; I'm planning on Koni yellows as detailed here, and a bunch of fresh OE/OEM suspension components (e.g. fresh strut tower bushings/bearings, e36 m3 OEM offset FCABs, stock control arms, fresh OE 325is buffer stops and spring shims, so on). As I'm staying stock 325is height and stock 325is sway, I don't really need to worry about roll center and I'm about equidistant between 325i and M3 ride height, to my understanding. I wasn't sure if that difference was enough to matter with stock-type M3 links and they're way more affordable than the adjustable aftermarket types, and I don't really need adjustment otherwise as far as I know. Obviously I'd rather not spend triple-ish the cost on those if I don't have to. The endlinks and offset bushings seem to be a good compromise to me where I get most of the street-spec M3 suspension benefits (caster, responsiveness, firmness without much additional NVH) without worrying about all the complications and expenses lowering an E30 brings, or the expense of OE M3 struts and 5-lugging plus all the bodywork concerns from wider track, etc etc.

Anybody have input or experience there? Thanks.

[e30m3s54turbo]

On one of my M car has upgraded S&T sway bars and H&R race springs installed 26 years ago. My friend helped me in his shop. I forgot why my are set up on control arm. It handles great for me. I don’t want to change the set up. On my other e30’ I’m using m3 links on an other m car and 325i.

[Maybe Magpie]

On one of my M car has upgraded S&T sway bars and H&R race springs installed 26 years ago. My friend helped me in his shop. I forgot why my are set up on control arm. It handles great for me. I don’t want to change the set up. On my other e30’ I’m using m3 links on an other m car and 325i.

How do you feel the M3 links are on the 325i compared to the stock control arm setup? Did you use the E30 M3 or E36 or early E36 M3 offset FCABs, or the regular E30 ones? To my understanding it tightens up the front end a bit, faster turn-in response and "cheats" the sway bar - i.e. it defacto makes it act like a stiffer and bigger diameter one even if you keep the stock swaybar due to the leverage stuff going on, and the FCABs' improved caster and stability at speed seem like they'd go well with a rack swap if I can afford it sometime. The shop I worked with on my 5-speed swap mentioned that stock M3 links should be able to handle the slightly higher ride height the 325is springs have without any issue as it's within their tolerances, I trust them but I'll obviously find out if that's the case once my suspension stuff happens down the road (and I will report back accordingly at that time).

If there were other spring options that were fairly high I'd be more interested in them, but even OESports from H&R are a smidge shorter than I'd prefer, let alone the Sports proper. My car is for autocross and spirited backroads but also daily duty is first priority in a region with toooooons of steep steep hills and not-so-great road surface conditions in some parts of it. That and the significant additional cost of figuring out roll center stuff and rear subframe adjustment retrofitting for camber & toe etc mean I'd rather not get the car any lower than it is. M20 oilpans aren't getting any cheaper! Don't get me wrong, aggressive posture is cool but I'm glad I've only scraped like twice ever in this thing (both on the same very tight, very steep, slightly banked downhill right-hander).

[mtech325]

I recently put M3 style endlinks on my car and it made turn in a little sharper using the same stock front sway bar, but I wouldn't call it a night and day difference, at least on the street. Not sure if it's something you'd want to do, but one way to use the HR OE Sport springs without lowering the car too much is to use the thicker 15mm spring pads in the rear, and use a camber plate that bolts to the stock front strut mount as it'll gain some stack height (like Ireland's street camber plate). For autocross you'll want some camber anyways otherwise the tires will get chewed up faster. If you suspension is original, it may gain some ride height anyways from having new strut mounts that aren't collapsed as well.

[Maybe Magpie]

I recently put M3 style endlinks on my car and it made turn in a little sharper using the same stock front sway bar, but I wouldn't call it a night and day difference, at least on the street. Not sure if it's something you'd want to do, but one way to use the HR OE Sport springs without lowering the car too much is to use the thicker 15mm spring pads in the rear, and use a camber plate that bolts to the stock front strut mount as it'll gain some stack height (like Ireland's street camber plate). For autocross you'll want some camber anyways otherwise the tires will get chewed up faster. If you suspension is original, it may gain some ride height anyways from having new strut mounts that aren't collapsed as well.

This is useful information, thank you. I don't really plan on messing with camber too much as I don't autocross THAT often, but that might be worth considering. I am unsure when my shocks were last changed, I suspect the 90s - they're not terrible via the shove-the-bumper test but sometimes when I go over bumps or drops it feels a little harsher than healthy ones properly would be. Thing is as I have to do other front suspension work anyway (namely the control arm ball joints) I'm planning on one fell swoop up front then the same in back as soon as I can manage thereafter. I thought while I was at it it was the best time. There's some other stuff I want to do that would be made easier by just dropping the whole front subframe anyway too - motor mounts, crank scraper, pan baffle, some intake and injector things, maybe reinforcements and steering rack. Out back I'm just gonna replace shock mounts (rogue eng reinforced ones), subframe, diff, swingarm, sway mounts & bushings, endlinks, and call it good, maybe CV boots and output seals if I gotta. I don't anticipate needing to do wheel bearings as they don't have side-to-side wobble or excess noise when driving, but they do make a little scraping sound when turned by hand. Next time I've got it jacked up in front I'm gonna try the feel-the-springs-and-hand-turn early diagnosis trick, didn't know about it last time I did. If they end up on their way out, I'll replace them too.

I'd like to keep the original springs as my car only has about 120kish right now and I like them being the fancy factory IS ones but if it works out to be best to go with the OESports I'll definitely give something like your idea a shot and just hang onto the OGs in my parts pile. Appreciated.

[digger]

i use the m3 style ARB links from turner as there are a myriad of lengths and they are still sealed

https://www.turnermotorsport.com/p-338618-turner-motorsport-custom-length-adjustable-front-sway-bar-end-links-pair/?pdk=Ag

one thing to note that if you add these the increase in stiffness at the wheel will change the balance so its best paired with an adjustable rear bar

[Maybe Magpie]

i use the m3 style ARB links from turner as there are a myriad of lengths and they are still sealed

https://www.turnermotorsport.com/p-338618-turner-motorsport-custom-length-adjustable-front-sway-bar-end-links-pair/?pdk=Ag

one thing to note that if you add these the increase in stiffness at the wheel will change the balance so its best paired with an adjustable rear bar

I got the Meyle HD ones from FCP because they were a good price and made in Germany. I don't really anticipate needing adjustable ones and if I do the Meyles were cheap enough I won't be too fussy about putting them in reserve. Good to know RE: the swaybar, what would you recommend if I'm keeping my stock IS front bar?

[digger]

I got the Meyle HD ones from FCP because they were a good price and made in Germany. I don't really anticipate needing adjustable ones and if I do the Meyles were cheap enough I won't be too fussy about putting them in reserve. Good to know RE: the swaybar, what would you recommend if I'm keeping my stock IS front bar?

i had specific reason to get particular length ones.

To be honest about the smallest rear adjustable bar i know of is 16 mm from whiteline which is what i have with a 24mm up front. Perhaps the softest setting may work with the stock IS front bar. I would install and see how the balance is regarding understeer or oversteer when pushing hard to the limit and adjust from there

[Maybe Magpie]

i had specific reason to get particular length ones.

To be honest about the smallest rear adjustable bar i know of is 16 mm from whiteline which is what i have with a 24mm up front. Perhaps the softest setting may work with the stock IS front bar. I would install and see how the balance is regarding understeer or oversteer when pushing hard to the limit and adjust from there

Right, I honestly don't think I'd need adjustable bars either given I'll have adjustable shocks, I'll follow up when I've got the front suspension worked out and then the rear thereafter but that probably won't be for a while. I don't mind a little body roll as long as it's manageable. Thanks!