[Surferdude]

What are you going round in Jason?

 
and don't say "circles"
BTW. 2.5 secs saving is pretty good.

[stkman]

Hi All,

It has been around 5 weeks since I replaced the existing 14mm rear anti-roll bar with a 20mm rear anti-rol bar. Time for a debrief!

After my initial impressions that the understeer was totally eliminated, I have found that there is still a slight tendency towards understeer. Not really noticable in the dry but it can be felt when pushing it in the wet (although must figure in tyres that are almost due for replacement). At no point have I been able to induce oversteer which I am very happy about ... understeer on a front wheel drive isn't too much fun.

In fact, I think it would be possible to go a bit larger than 20mm on the back for the ultimate in handling although for on the road, 20mm seems perfect to me. The word that springs to mind is 'effortless' when it comes to driving the car. It is very easy to drive very quickly due to the torquey diesel and the safe handling. There is no creaking which I noticed in my previous car with a larger rear anti-roll bar. In fact in that car, driving at an angle out of a driveway would lift a rear wheel.

I have no intention of going further with the handling by installing lower and/or firmer springs. Getting too old for that - prefer comfort now although love the new handling. I feel Hyundai could get away with a 20mm rear bar as standard although even a 17mm rear bar as on the European i30s would be great.

Disclaimer : I am very happy with these results on my car and am glad I have gone down this track but my opinions of my results are my impressions only - the larger bar may be damaging to the vehicles structral integrity in ways I don't know about!

Andrew

[jason117]

Surfer,
My best is 2min 11.8, which is not world beating by any means but quick enough to put a grin on my face, and still be confident of driving the thing home without any damage (except to the tyres and brakes )
Most, if not all of the other cars are running on r-spec tyres. The only fellow on standard road tyres was a nice guy in a Skyline GTST turbo jap-import thing who pipped me by .6 of a second by the end of the day. The i30 held it's head up proud!

[Surferdude]

Surfer,
My best is 2min 11.8, which is not world beating by any means but quick enough to put a grin on my face, and still be confident of driving the thing home without any damage (except to the tyres and brakes )
Most, if not all of the other cars are running on r-spec tyres. The only fellow on standard road tyres was a nice guy in a Skyline GTST turbo jap-import thing who pipped me by .6 of a second by the end of the day. The i30 held it's head up proud!

Sounds good.
I've not driven around Eastern Creek but have done a few laps of the short circuit at Oran Park (in the company car of course )
And Lakeside and Surfers Paradise back in the day. It's great fun and I've managed to get at least one of my kids to experience it, too.

However, I must admit to still prefering a nice, winding gravel road through a pine forest,
At night.

[agentr31]

man i would be bloody happy with a 2.5 second gain on the track! thats quite good! especially for such a cheap modification!

[jason117]

Agent, yes the 2.5 second improvement was far more than I was expecting, so I was very happy at the end of the day ( my fastest lap was on the final lap of the day ). Although the car has only had the rear sway bar changed I've lost 30kg from my gut since my last track day so the power-to-weight ratio was improved too.

[Surferdude]

30kg
WOW!

[Dazzler]

30kg
WOW!

yeah.. his mum says she is seeing less of him now 

[jason117]

Yep, Im a fattie!

[agentr31]

i dunno... im pretty fat!

great news on the weight loss too man! *high fives*

[Paolo5]

I would just like to put in a good word for Todd at Signature Swaybars in Taren Point, Sydney.

He fitted a 20mm rear bar to my car last Monday. It took him less than 10 minutes to remove the original bar and around 45 minutes to install the new one.
 
I travel over twisty roads each day and the new bar has reduced the previous i30 OE wallowing  significantly. My car sits much flatter around roundabouts and when pushing-on through bends. I haven't noticed that the drive is any harsher at all with the new bar. Makes me want to find new bends to try out...

Thanks Stkman, Jason117 and Bobbyd for providing the incentive to get this done on my own car.

It was $220 and I gave him a week's notice. He painted it black on my request. Fitting was $50 extra. This has been the second-best birthday present that I have ever given myself!

It handles like a different car. BARGAIN!!!

[bobbyd]

Cool, good to see that my enquiry with Signature and Todd's effort to go out and measure the i30 up and make a rear bar for it has paid off for other people.  I'm still keen to get a bigger front bar, i think that this would perfect a good set up into a better one.  Having said that the trouble may be more than its worth?

On another note i ended up having my springs reset- after taking them out and having a local spring manufacturer reset them i was initially let down- i asked for 35 mm lowering but that didn't eventuate and i was given a refund.  The answer as to why it didn't work was that apparently some new car manufacturers are using "anti sag" spring coils which will not easily reset to a lower height.

Having said that i think it eventually sat down about 25mm lower and in hindsight this is a good compromise, the front bumper does occasionally touch on the odd dip or raise when parking etc.  But at least the springs aren't too firm coupled with the 18" wheels.

I look forward to someone finding a front bar upgrade.  Keep us posted

[Paolo5]

Interesting thought bobbyd...
The auto wrecker not far from my workplace has a totalled i30. I will get a price on the front bar from them this week.

If the cost of this bar is reasonable, I could send it to Sydney to be the template for a thicker bar to be manufactured.

Would there be any interest from fellow i30 members in approaching Todd Selby (yes, as in Selby Swaybars of old) at Signature Swaybars for a multiple-purchase price of front bars?

[2i30s]

if the price is good,im in. 

[Paolo5]

Great 2i30's!
Would that be 1 or 2 bars for you? (plus 1 for me)

Hey guys, I have no experience with suspension mods but have a reasonable grasp of the theory and and I'm wondering what you will be hoping to gain from stiffening the front bar.

Will you not be in danger of negating the newly found more neutral balance gained by stiffening the rear bar? I'm seriously thinking of doing the rear bar but touching the front seems to be the wrong option.

Someone?

[Surferdude]

Hey guys, I have no experience with suspension mods but have a reasonable grasp of the theory and and I'm wondering what you will be hoping to gain from stiffening the front bar.

Will you not be in danger of negating the newly found more neutral balance gained by stiffening the rear bar? I'm seriously thinking of doing the rear bar but touching the front seems to be the wrong option.

Someone?

Yeah Pip. I tend to think you're right.
Some research is needed. I'm sure stiffening the front bar will increase understeer.

[agentr31]

pip is right as far as i know...

[Duckman]

I'd be interested too, just the rear

[2i30s]

in most of the cars I've owned I've beefed up the front sway bar and it took away the understeer [but they were rear wheel drive cars] would you get more understeer  in a front wheel drive car with a bigger front bar? the i30 is the first car I've owned that is front wheel drive.  a larger rear bar takes away oversteer and some understeer. 

in most of the cars I've owned I've beefed up the front sway bar and it took away the understeer [but they were rear wheel drive cars] would you get more understeer  in a front wheel drive car with a bigger front bar? the i30 is the first car I've owned that is front wheel drive.   a larger rear bar takes away oversteer and some understeer.  

My understanding is that irrespective of whether FWD or RWD the sway bars will promote the same result, although perhaps at some (more extreme) point whereby any body-roll reduction will keep some tyres squarer to the ground and result in better control that overrides the basic theory.

Generally, front (stiffer) bars loosen the back, and rear (stiffer) bars loosen the front. What I mean by this is that when pushed near the limit the sway bar causes the end that it's attached to to lose grip thus moving the point of rotation closer to the other end.

Boiled down, front bars move the balance towards understeer and rear bars move the balance towards oversteer.

FWD or RWD just determine the intrinsic balance, with FWD (that we have) tending to understeer - so stiff rear bars reduce that and stiff front bars enhance that.

Of course it's the relative stiffness between them that determines where the balance shifts to. Taken too far though, the wheels on each axle will act more like a solid axle (non-independent) and the ride at least will be intolerable; perhaps a bit like stiffening the springs beyond reasonable.

And more: why RWD (assuming engine in front just like FWD) cars tend to oversteer is because when power is applied the rear wheel grip will be reduced as the tyres struggle to maintain full contact (and as soon as you hear a chirp you know they aint) and they eventually "let go". Because the engine is in the front though they will probably start out to oversteer simply because that's where the weight is and the centrifigal balance is towards the front (weight).

RWD then can be understeer turning to oversteer and FWD can be understeer turning to... well understeer unless you stiffen the rear bar enough to cause the rear to step out. Even then it will probably only happen if the power is cut mid-corner. FWD is IMHO very dull.

[bobbyd]

Interesting thought bobbyd...
The auto wrecker not far from my workplace has a totalled i30. I will get a price on the front bar from them this week.

If the cost of this bar is reasonable, I could send it to Sydney to be the template for a thicker bar to be manufactured.

Would there be any interest from fellow i30 members in approaching Todd Selby (yes, as in Selby Swaybars of old) at Signature Swaybars for a multiple-purchase price of front bars?

Hell yeah, definitely keen if the price is right.  Also find out from the wreckers if the bar can be removed and replaced without dropping the front end.

[bobbyd]

Todd explained to me that a stiffer front bar will be better- just not as much improvement as the rear bar upgrade, I'm not sure that it devalues the rear bar upgrade, its just not as noticeable an improvement.  But im a bit fussy, so i notice the front roll still when pushed hard.  If i didn't live in the hills i probably wouldn't bother- but i do so i do a lot of cornering.

[Paolo5]

The wrecker that I rang wants $150 for the front bar. He didn't know if the front bar comes out easily. He wasn't all that helpful.

A new OE bar is $175. I think that $150 is way-over-the-top. Maybe another member could find a better deal somewhere else?

I rang Todd from Signature Swaybars and asked him about a discount for a multiple order (of say 5 bars).

He wasn't able to give a firm figure as he hasn't seen an i30 bar and consequently doesn't know how many bends it has. He said that he could give a 10% discount over the single unit price if (say) 5 were ordered.

Todd said that in a front-wheel drive vehicle, if, say, a 20mm bar was installed in place of a 14mm rear bar (ie a 6mm increase), then an upgraded front bar would be best to have less of an increase to best complement the beefier rear one. So if the front OE one was 20mm in diameter (for example...don't know what it is in an Oz model) then the optimum upgrade for the front would be a bar 23-24mm in diameter.

I have contacted the person who is selling the Ebay wreck mentioned on another thread today and asked what he would accept for the front bar on his car. I will let you know what his reply is.

[agentr31]

yay so my link is sort of useful!

[Paolo5]

Yeah! You can buy the wreck and then send the swaybar to Todd....bargain...

Seriously though, thanks for the link Agent. If it was a manual I might be tempted to buy it myself.

[Surferdude]

The old Selby suspension family must be pretty widespread these days.
There's another one got the Goodyear franchise in Bowral.

Re: rear sway bars my Datto rally car (Datsun 1600s are/were notorious understeerers and I finally resolved it with several mods).
But, relevant to this thread, I had a locked (read "welded") diff and that used to really push the car in corners unless I got super serious and flicked it in hard. As this wasn't necessarily the quickest way through the corner I added a rear sway bar (Selbys actually), This had the effect of starting oversteer progressiely but pretty much as soon as there was some weight transfer and I could then control the car's direction on the throttle.
For anyone who doesn't know, a welded diff was the poor mans Limoted Slip Diff back in the day.
And the Datto didn't have a rear sway bar as standard so the Selbys unit came as a complex package including angle iron bracketing - but very effective.

[agentr31]

LOL welded diff... bad.. VERY BAD... massive understeer inducer, then an oversteer monster!

[stkman]

I measured the front bar as I was rotating the tyres ... 23mm. This is a NZ car which seems to be the same as Australian spec cars.

Andrew

[Surferdude]

LOL welded diff... bad.. VERY BAD... massive understeer inducer, then an oversteer monster!

Well no. It was in fact a very precise and controllable machine which drew favourable comment from many observers, although only a couple of guys knew about the diff. It was used by a guy who won the WA State Championship with it and his mate who did some work on my car and lived in Qld appropriated it for me.
Although I have no doubt that if you did nothing else but fit a welded diff you'd get what you are suggesting.