SC300LS1

I am completing an LS swap in my SC400 and wanting to know if I should upgrade the front and rear sway bars .

RudysSC

It certainly never hurts. A beefier rear sway bar tends to make the rear more "settled" while also increasing the cars ability to "rotate" around a corner (aka increasing it's tendency to want to oversteer, which comes in handy with a big car with a lot of tire like you'll need w/ that LS). A front bar will help settle the front and balance things out as well. They're a great upgrade especially in heavy cars that are prone to body roll.

KahnBB6

iTrader: (5)

The 1993-96 Supra TT rear sway bars are 22mm. The uber rare discontinued MKIV TRD rear sway bar is something like 23mm or 24mm. Any MKIV rear swaybar will require OEM or aftermarket reproduction MKIV rear subframe mounts. The swaybar anchor points for the MKIV style is to the subframe itself whereas the 20mm SC style factory rear swaybar is a different shape and anchors to the trunk floor. I believe both Battle Version and Figs Engineering make MKIV style subframe mounts capable of fitting the MKIV style rear swaybars.

A couple of SC style aftermarket front and rear swaybar kits are sold. I don't recall who makes them these days but they are out there.

SC front swaybars are nearly identical to MKIV style swaybars. Diameters are the same but thickness/rigidity is stiffer in the OEM Supra front swaybars. And the Supra TT OEM front swaybars (and Z30 Soarer front swaybars) in additon have an ever so slightly different bend to allow for the stock intercooler piping (MKIV TT and Soarer JZZZ30's) to go behind the radiator and not interfere.

There is certainly a difference from stock. Helping them should be: replaced OEM or Supra MKIV front lower control arms if the rubber and ball joints are worn out, a set of new Daizen Sport Tuning or Figs Engineering SC/MKIV power steering rack bushings, an MKIV "Lance" style alignment or as close to one as possible, a limited slip differential (1.5-ways and 2-ways will act differently of course) and a good aftermarket suspension that offers better chassis control and response than stock regardless of ride height changes or lack thereof. Staggered tire setups with excellent rubber also help. I like a 235 or 245 front and 265, 275 or 285 rear setup on 8.5-9"wide front and 9.5-11" wide rear rims myself.

KahnBB6

iTrader: (5)

Any MKIV style swaybar will require MKIV OEM subframe mounts. Any SC style swaybar does not. The millimeter differences in diameter are only part of the story. The SC style swaybars (OEM or aftermarket) anchor to the trunk whereas the MKIV style swaybars anchor to the subframe mounts.

Really, the SC and MKIV subframe mounts are exactly the same (rubber formulation aside) other than that the MKIV subframe mounts have very specifically placed mounting plates for the swaybars.

Personally I have been running a 93-96 Supra MKIV TT 22mm rear swaybar with OEM MKIV subframe mounts for years and am quite happy with it for a performance street setup. The 23mm (or 24mm?) rare TRD rear sway bar for the MKIV would be overkill outside of a track car IMO.

Daizen, Whiteline and other companies offer SC style swaybars and those can be effective too, albeit at different loading points on the chassis. You can probably still find the 93-96 TT 22mm Supra rear swaybar used and if the MKIV rear subframe mounts are no longer available new those can be picked up used or a couple of aftermarket suspension companies make their own with solid mounts. I'd recommend the OEM ones if you can get them though for kinder NVH.

FYI, the MKIV Supra NA's from 1993-1998 all used 20mm rear sway bars (with the different mounting points from the SC) but the 1997-1998 Supra TT's also used those same 20mm sway bars. Only the 93-96 TT's used the 22mm versions in the rear.

For a 100% street car probably both styles will do but the MKIV style mounting setup is superior no matter what. How much you'll feel it will depend on the rest of your suspension setup, tires, alignment settings and whether or not an LSD also adds to the overall changes.

You should be perfectly fine with a 22mm rear sway bar. That's enough overall diameter for the majority of SC's and MKIVs.

RXRodger

iTrader: (2)

So there is not enough information to answer your question. What are you trying to accomplish? If you are tracking the car and you want to loosen up the rear, then yes install the larger bar. If you are just street driving the car, then leave it alone. Just depends on what you are looking for.

shajbot

iTrader: (3)

I have SC style Whiteline adjustable RSB on my SC300 and here’s my observations:

Hardest setting (closest mounting hole to axis of bar) - car feels flat in corner at slow to moderate speed but car becomes unsettled when hitting mid corner bumps. High speed cornering actually feels less confident-inspired because you could feel you’re nearing traction limit and could oversteer any moment.

Softest setting - car feels a tad more body roll but lots more grip because the tires don’t hop over bumps due to the sway bar springing back and forth. Increased body roll at high speed but the tires dig in and maintain traction which allows to carry on even higher speed. My choice currently.

My setup for reference:
- Espiler Lowering Springs (Progressive) on Supra MKIV Bilsteins shocks
- Front Supra MKIV Swaybar
- Rear Whiteline Adjustable Swaybar
- Rear 275mm width Michelin Pilot Sport
- Rear 1.2-1.5 negative camber
- Stock SC300 Open Diff (cannot overstate the importance of this is in term of spirited driving or racing, you could have a great suspension setup otherwise until one of the rear wheels loses grip)

theguy0075

This is a little confusing. Are you saying that you want and open diff?

KahnBB6

iTrader: (5)

^^ I think he must have been referring to that just being his current setup and that he strongly would prefer a limited slip differential.

That's a nice overall configuration!