98GSOwner

Hello - I'm looking for some input. It's been a long time since I've posted, but I've recently read every 2GS sway bar thread here and on the Web trying to educate myself. My '98 GS4 is in very nice shape with only 100K miles. It is stock with the 17X8 wheels and new Michelin Sport Pilots. I installed Daizen sway bar bushings years ago. However, I've been driving the car more recently, and want to reduce the body roll more without lowering the car. Here are my thoughts:

1) I'd like to replace just the sway bars. The Megan Racing units are 32MM/19MM, both hollow, and include bushings. I can't find any stiffness specs on these, but they seem to be of good quality and cost about $300 for both. The EMUSA Ebay bars worry me due to low price and unknown quality. The Figs bars are pricey (about $500 shipped) and I believe their 30MM solid front bar (75% stiffness increase over stock) may be stiffer than a similar 32MM hollow bar like the Megan unit.
2) My main concern is that I've read about many people bending endlinks and/or breaking hollow rear bars. I know the stock 2GS is softly suspended and upgraded bars with put more force on the endlinks and bars. I would like stiffer bars, but nothing like the old TRD blues which I understand are (were) the stiffest available.
3) I don't drive the car hard, and I'm careful to avoid potholes. I just really don't like the lean....

The question - Will I likely be trouble-free with just a sway bar upgrade, or am I risking bending/breaking end-links or cracking the bars? I'm strongly considering the Megan units, and I will install them myself.

I greatly appreciate any input, especially from others who have upgraded sways on their 2GS while keeping stock springs/shocks. Thank you very much!! Paul

GS400V8

iTrader: (4)

I think out of all the 2GS cars in the world there is probably only a handful of people who have snapped sway bars or end links.
If you keep the car stock ride height, you won't have to change the rear end links to moddified ISF ones due to the end links pushing up on the sway bar at an angle.
Although keeping stock height is not the best for performance, sway bars do wonders on this car. I have a 30mm hollow front and 20mm hollow rear.
If I could do it over, I would probably go with the solid Figs. I think they are the best in the market right now and have lateral movement collars.

98GSOwner

Thanks GS400V8 for your input. I remember your posts where you got a set of the EMUSA units before they reduced the size of the rear bar. It sounds like they've worked well for you despite the seemingly "too low" price, which is great news. Why would you spend the $500 for the Figs if you were to do this again? Are you looking for a stiffer set-up with the solid bar?

The Megan front bar does have the collars you mentioned. In the absence of specs from Megan (I emailed them and got a "no spec sheet" answer), I used some estimates. I've read that a "rule of thumb" is that a hollow bar needs to be about 1/8" larger to have equivalent stiffness of a sold bar, all else equal. 1/8" is about 3mm, so the Megan 32mm front hollow bar should be similar in stiffness to a solid 29mm bar. The Figs solid front bar is 30mm and listed as 75% stiffer than the stock 28.5mm hollow bar. Doing the "torsion math", I estimate the Megan front bar is about 60% stiffer than stock. Compared with your hollow 30 mm bar, the Figs bar would be much stiffer. My goal was to add stiffness, but not too much..... Your thoughts? Thank you! Paul

GS400V8

iTrader: (4)

No problem! Yes I lucked out big time on that one. Yes I would do the Figs because sure I spent only $120 to $150 on them, but they have no collars and I think that combined with a more solid bar would handle even better.

Honestly it is hard to measure these numbers because when looking at hollow bars, the wall thickness of the tube is more important than the over all diameter.
Especially on a car that is not lowered, let alone a lowered one, 60% stiffer in the front really only feels maybe like 30% just because of how heavy these cars are.
75% probably feels more like 60% you know? The way a mod feels is almost never linear, it's always in small steps until you start to feel it. I've found this applies to performance mods, handling, etc.
The rear bar is what really does it though. It really makes the car feel more nimble, and actually helps the front turn as well.

I think you'll be happy with the Megans because it is a huge upgrade but IMHO the Figs are probably the best handling out there

firelizard

iTrader: (1)

I haven't compared against other swaybars but I'm happy with my choice of TRD Sportivo. They complement my lowering springs without being too stiff.

98GSOwner

Thanks Firelizard for your input. Do you happen to know the specs on the Sportivo bars? (size, solid/hollow, stiffness over stock) My understanding is the the Sportivos were a less-stiff version than the Blues, and a nice choice. Too bad they were discontinued many years ago....

GS400V8 - Yes you are right that guessimating sway bar stiffness is just a guess. Tubing wall thickness, steel type, bend angles, lever length, etc., will impact the stiffness. I was struggling to get some relative measures of the various choices. Sloppy math is hopefully a bit better than no math at all....

firelizard

iTrader: (1)

That's right, the Sportivo line was a milder version of the standard blue TRD stuff.
They consist of a 31.8mm hollow front sway bar and a 16mm solid rear sway bar with harder-than-stock rubber bushings.
They'll turn up on Yahoo! Auctions Japan or UpGarage every once in a while for not too much money. Somewhat less common in North America because people get the blues, but I've seen a set on eBay before.

98GSOwner

Kitabel - You are right about the variables. It is frustrating that there are many parts for sale without specs. I did some searching and found some tube wall thickness data for a range of hollow Corvette bars. This data indicates that bars in the 30-32mm range may have about a 4mm wall thickness, while smaller bars below 20mm may have 2mm walls. Of course other variables, such as steel type, will impact stiffness as well. Thanks for your help!

Does anyone else have correct wall thickness data for any of the GS hollow sways?

ZanderZ32

iTrader: (2)

Whos gonna be the first to cut them up and see?

On another note I have the "too cheap" sway bars and they are excellent. I had to have one of the welds cleaned up but otherwise for how cheap that are I'm very happy.

98GSOwner

Kitabel - Can you run some math on a 30mm and 32mm hollow bar if we assume a 4mm wall thickness? This would cover the EMUSA 30mm, TRD Sportivo 31.8mm, and Megan 32mm hollow front bars as an estimate. Even if I am guessing correctly on the wall thickness, I realize we'd still have metal and bend differences. Thanks!

98GSOwner

Thanks Kitabel for the info! I see that this data seems to confirm that "rule of thumb" about the 1/8" larger hollow bar matching a solid bar. If I take your 32MM hollow number (253) and compare that to a 29MM solid you posted earler (250), they very nearly match. 1/8" is 3.17MM so the info we have seem to make sense. Unfortunately, we are still guessing on the specific bars available for our cars. I have been focusing on the front bar in this discussion to eliminate the lever arm length variable associated with the adjustable rears. If time and $ were no object, it would be interesting to buy all the bars and subject them to a torsion test to see exactly what each one measures out at. Perhaps a test to the breaking point would be more interesting, at which time we can easily measure the wall thickness....

Thanks ZanderZ32 for providing your input. Interesting that you had a weld "cleaned up" on your EMUSA bar. Were you concerned about strength or was the weld just messy and inviting rust? I believe the EMUSA bars are painted, not powder-coated like the Megan and Figs bars.