Aftermarket Swaybars w/ Soft H&R Sport Springs

[Panici]

Hi Everyone!


I recently installed a set of upgraded swaybars on my stock suspension 1990 Miata.
There is a noticeable difference in body control and roll compared to the stock bars, with no reduction in ride comfort on the street.
I was impressed and it got me to thinking about the E30.


The 50whp bump when I went from the stock M20 to the M52 in the E30 already made the H&R Sport springs (w/Bilstein Sport Dampers) feel undersprung. I'm doing a turbo build now which will approximately double the power of the M52. Going to need some more body control to keep the car planted at speed.

My long-term plan is to save for an expensive set of coilovers (Öhlins etc), but in the interim I was thinking a set of thicker aftermarket swaybars could effectively add some springrate in the corners without compromising ride comfort.

I love taking road trips in the E30 and NVH is a big concern.
Although it will see the occasional causal track day for testing & tuning, I want to set it up for street driving and comfort.

.

I welcome your input. Suggestions for swaybar sizing and brand would also be helpful.



Because everyone likes pictures: Here's a shot of the two cars together.

[jbontke]

I too have thought about softer springs and thicker sway bars. I have Bilstein dampers and H&R race springs. I have an s52 waiting to be swapped in and was wondering how the weight would effect the spring rate in the front. I am not crazy about the H&R race spring harshness (its not awful, but nothing like the eibach springs before it). This makes me consider keeping the race springs and see how the s52 weight treats the ride.

[Northern]

I don't have experience with a softer sprung setup, but I think a bigger front sway ~23mm would be helpful universally.
Basically anything from a 21mm cabrio front sway to something like an ST 22mm.

Rear sway I don't know, probably helpful to a point. As far as I understand it, upping the rear is only going to make the car more tail happy and I'd probably try the front upgrade, then add rear until you're happy.
I think the iX and m3 rear sway is 2.5mm larger than stock, if you can find one.
Some of the aftermarket kits come with huge rear sways (19mm or more) and that's probably excessive.

[e30davie]

I have oem Mtech 1 springs with koni yellow shocks and i put in a white line 16mm rear sway bar and it made a significant difference to how the car handles, with no real change in comfort etc. It does quite well in basic track driving too. no race car of course but its enjoyable and confident at speed.

I have the front mtech sway bar that i believe is slightly bigger than the regular sway bar.

So I would recommend, the rear bar i got is adjustable in that it has 3 holes to choose form. I just put it in the middle hole and never touched it again.

Years ago i had an s15 silvia with oem suspension and i put thicker front and rear bars on. Wasn't any good. car felt a bit weird as it was soft but then i dunno had too much roll stiffness. probably needed slightly stiffer springs to make it work properly.

[digger]

Whiteline 24mm and adjustable 16mm in full soft was pretty well balanced with m-technic and softish eibach

[Panici]

Bump for more options if you have them.
Definitely going to pull the trigger on a set this winter.

[Panici]

Looking at the ST 22mm/19mm kit.

Does anyone have this kit and can speak to the quality?

[moatilliatta]

Id look at the IE setup with a 16MM rear bar.

[Panici]

Id look at the IE setup with a 16MM rear bar.

Why such a small rear bar?
I'm hoping to both offset my soft springrates and help reduce wheelhop (act like a solid rear axle) with a stiffer rear bar.

[moatilliatta]

Softer rear bar usually helps put down power.

A big rear bar would be a band aid tokeep wheel hop down. Go for the twin ear and Group N rubber bushings for street car. 85A if you dont mind some diff whine. 75D if you dont mind more. Z3M diff bushing or vibra technics.

[Panici]

Softer rear bar usually helps put down power.

A big rear bar would be a band aid tokeep wheel hop down. Go for the twin ear and Group N rubber bushings for street car. 85A if you dont mind some diff whine. 75D if you dont mind more. Z3M diff bushing or vibra technics.

Want to use it as a piece of the puzzle.

Have my eye on a twin ear bracket from Garagistic, open to other brands if you can suggest any.
Have you had experience with the vibra technics? They are expensive but were in the "maybe" pile for me. Z3M are ridiculously expensive and not a viable option IMO.

Group N rubber subframe bushings are NLA now, but I was planning on Revshift 80A Subframe Bushings.

Open to any other suggestions you may have for both body control and wheel hop, without making the car stiff or loud. It's a road-trip car for me.

[moatilliatta]

I would say most your poly bushing are really cheap.. so all other options look more expnsive. :)

I like the vibra technics, Have used in a few cars. I would say between stock and 75D your about 3/4 nvh there.

Power flex makes some street ones but always seem to get bet up with use.

[digger]

I also do not understand why e30 people want such a big rear bar. There does seem to be a trend for low rear spring stiffness relatively speaking but still seems mismatched.

on the Eibach setup I had 24mm front and 16mm rear on softest setting and it was perfect

there is a solid oem diff bush for e30 but it’s same price as z3m lol

[hasa]

Pretty much everyone race E30 or other rwd cars here WITHOUT rear bar including me.

Drifting may have different requirements. There thick rear bars are popular.

[moatilliatta]

Ground control 525/700 or with stock Bilsteins sports or valved konis with a softer rates rides better than lowering springs with BS. I’m not sure why everyone loves BS..

If ride quality is important I’d get matched valved shocks with springs. Then you can have a stiffer rear kit to help with wheel.hop.