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Guest Message by DevFuse
 

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RX sway bar ??


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35 replies to this topic

#1 Guest_toybuilder_*

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Posted 15 August 2003 - 10:10 AM

The front RX sway bar is larger than the stock sway bar on my ea82 Loyale wagon, right? Is this a good handling upgrade?

Thanks

#2 Guest_baccaruda_*

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Posted 15 August 2003 - 11:18 AM

yes, yours is 18mm, the one i'm sending you is 19. An XT6' is 20mm. I'll email you a chart later, off to work now.

#3 Guest_james hogan_*

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Posted 15 August 2003 - 03:02 PM

Put that larger swaybar on the front without doing anything to the back and you will be the Plow King.
Expect massive understeer.

Just an opinion.
Jay

#4 Dennis ex24

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Posted 16 August 2003 - 12:36 AM

jay is right

your subaru will now handle like a buick, upgrade the rear as well

#5 toybuilder

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Posted 20 August 2003 - 04:53 PM

My wagon has no sway bar in the rear, sounds like that is the first upgrade that I should make. Any recommendations on which sway bar to use in the rear if I use an RX bar up front?

Will my car handle much better with these mods? Are they worthwhile?

Thanks

#6 Dennis ex24

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Posted 20 August 2003 - 05:14 PM

the biggest you can get easily are from an XT6, but i really dont see a problem with the RX swaybars

its a subaru - so its going to handle like garbage either way but it may make some small improvement

#7 gravelRX

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Posted 20 August 2003 - 06:44 PM

What I did is get the RX, GL and XT6 swaybars F&R and am planning on swapping them out until I find the one that suits my driving style. Putting GR2's on the back this week Should tighten up the rear even more.

I grew up on rear wheel driven, overpowered cars.
86 Mercury Capri (Mustang clone with built 5.0 and many suspension mods, 1971 510, with a severe 1600 with Mukuni's, again, many suspension mods( yes, that LSD), 1965 Buick Skylark GS 401, 16x8F 16x10R" wheels with Global West suspension. Blah, Blah.

The point I'm dancing around is it will take a bit of time to acclimate to the changes in handling.

Do things one at a time and drive the car for awhile. If it oversteers to much for you, go with the smaller front bar. Still to much, next biggest, and so on.
Remember tire pressure and toe have a lot to do with turn in and tire deflection during corners.

Jay


Jay

#8 Dennis ex24

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Posted 20 August 2003 - 06:50 PM

sorry to highjack...

jay did you get my email?

#9 baccaruda

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Posted 20 August 2003 - 07:04 PM

have i asked for your address yet so i can package it up?

#10 gravelRX

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Posted 20 August 2003 - 07:13 PM

Thought I replied. just checked and it doesn't have the arrow thingy in it.

Trying to work out coming to the dragstrip for the Subaru meet on the 13th. Will let you know.
I'll reply to Email soon.

highjack conspirator,
Jay

#11 Dennis ex24

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Posted 20 August 2003 - 07:23 PM

just wanted to see if you got it, we havent talked in a while - my bad

whenever you get time

end hijack.

#12 XSNRG

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Posted 21 August 2003 - 12:18 AM

What is understeer and oversteer?

On my '87 RX coupe, it came with 16mm rear and 18mm front. I replaced the rear with a 20mm and the front with a 19mm (have a 20mm too)

What would be the results of a stiffer rear bar? 20mm rear vs. 19mm front?

My car squeals the front tire going into a corner (pushing?) The back end doesn't feel like it wants to come around at all. Is this because of the bars or front wheel drive? Should I go to the 20mm front bar?

I didn't seriously test any corners until after I made changes, I know, dumb.

Also I put on the stiffer wagon springs on the back and lowered the car about 1.5 inches by removing a coil from the front and rear (further stiffening the spring ratio)

The car rides firm and corners noticeably flatter.

Ideas, comments?



BTW Jay~I had a '65 Buick Skylark GS401! I loved that car till a lady in a Honda pulled out in front of me (before the brake mods LOL) It was silver with the wine (light burgundy) interior. A Classic!!!

#13 Hondasucks

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Posted 21 August 2003 - 12:28 AM

I just put a XT6 rear bar in my GL turbo, I have the XT6 bar for the front too, haven't put it in yet though.

So your Buick was actually DAMAGED by the Honda????

#14 Caboobaroo

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Posted 21 August 2003 - 01:53 AM

weird, a steel horse was damaged by a little sheetmetal rice car..... thats very odd:confused:

#15 beauregaardhooligan

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Posted 21 August 2003 - 03:07 AM

Understeer is when you can't turn the wheel enough to go where you want.
Oversteer is when the back switches ends on you, much more fun!
:headbang:

#16 XSNRG

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Posted 21 August 2003 - 09:07 AM

LOL the buick got a bent bumper and fender (easy fix) I sold it to my friend that wanted the car really bad.

THE BRAND NEW HONDA WAS TOTALLED:headbang: :banana: :headbang:

#17 Superoo

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Posted 21 August 2003 - 01:54 PM

"Put that larger swaybar on the front without doing anything to the back and you will be the Plow King.
Expect massive understeer."

Obviously the above statement is like he said "just an opinion". I find it hard to believe that going 1mm thicker on a front sway bar is going to create a "plow king". The car doesn't have a rear sway bar now and with an 18mm front they don't handle badly. You may even see some improvement with only the 1mm increase in front sway bar size. Someone else said it's going to handle like garbage either way "because it's a Subaru" so why bother (just another opinion?).

FYI to mount a rear bar on a car that hasn't ever had one you'll need the suspension arms, or a least the brackets off the arms of a car with a rear sway bar to weld on your suspension arms. Given that your modifying a wagon (I'm assuming a wagon has more weight over the rear axle than say an RX) then you might get the best performance from a slightly larger rear bar, i.e. the RX bar in front and the XT bar in back. Just my 2.
LenHorn

#18 gravelRX

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Posted 21 August 2003 - 08:04 PM

Well Len, let’s break it down a little.

Sway bars are put on a car to limit the roll angle of the car during lateral acceleration and deceleration.

Since tires develop the maximum amount of traction when they are perpendicular to the ground (and the tread is parallel) that’s what you’re going after. Subarus are notorious for little to no usable camber adjustment. It has an innate inability to keep the outside front tire perpendicular to the ground during corners. In fact, they are forced to positive camber setting when pushed hard. Understeer.
Standard Subaru engineering.

It’s also a safeguard when Japanese manufacturers brought over cars to the US. The average driver can control understeer, not oversteer. Domestic cars too, for that matter.

Back to the topic.

Sway bars increase roll stiffness and they are, by far, the cheapest and easiest modification to increase roll stiffness on a Subaru. When you turn your car, one wheel will be up because of compression and one will be drooping down. The sway bars limit the roll angle of the car by using torsional stiffness to resist one wheel going up and the other going down.

If a car has understeer, too much of the load is on the front outside tire. By increasing the size and effectiveness of the REAR swaybar, some of the load can be transferred during cornering to the outside rear tire.
This will decrease the load on the front tires and make the car handle in a more neutral fashion. The very opposite is applied when increasing the front.

Simple. No not really.

The stiffness of a swaybar increases very quicky as its diameter is increased. The stiffness is a function of the diameter to the fourth power.

For example: A 1 ¼” diameter swaybar is 2.44 times as stiff as a 1” swaybar.

Now, I’m too tired to do the math right now, and you’re welcome to, but 1mm will change the understeering characteristic of the wagon enough to notice. Especially in sharp, on throttle turns. Let’s not forget about weight transfer. Get that long wheelbase car nose high in acceleration, with the weight transferred to the rear, then cut the wheel. Push.
Panic, jump on the brakes, overload the fronts, transfer weight off the rear. Push.

A rear swaybar will help balance out the weight in a lateral manuever by not letting the trailing wheel get too high and thus not help with traction. It will help take the load off the fronts, too.


You state that “The car doesn't have a rear sway bar now and with an 18mm front they don't handle badly.” Okay. You must not drive the same Subaru as I do, or do the same Autocrosses or Rallycrosses I do, or look to increase the handling as much as I do.

You post here and bust my chops about my opinion. Sad thing is, I’m going to have to agree on the swaybar choices you suggested for his wagon. See, you've got one.

You quoted someone saying that they(Subarus)handle like garbage. Well, fix it. Do some research, figure it out. I agree comments like this are also an opinion.

Yes, I stated outright what I said was an opinion. But opinions are usually based on fact if they are worth a damn.

James Hogan

#19 toybuilder

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Posted 21 August 2003 - 09:17 PM

Thanks for all the info and opinions. I going to experiment and see what works for me. Now I know where to get started.

Thanks

#20 XSNRG

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Posted 21 August 2003 - 10:59 PM

Thanks for the in depth explanation Jay:D

#21 gravelRX

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Posted 22 August 2003 - 07:52 AM

I'll try to get into spring rates after vacation. Specifically Subarus if I get enough info. More opinion, eh?
Doing spring swaps on the RX soon.


Jay




Edit: spelling

#22 Superoo

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Posted 22 August 2003 - 10:26 AM

Now you've given Toybuilder (and everyone) something he can use. You are obviously very knowledgable. I guess my "issue" is more about my perception of your reply. I saw it as a critique of someones planned modification with no real help given (in my opinion).

Later
Len

#23 DerFahrer

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Posted 01 April 2005 - 02:53 PM

See? I'm not a n00b. I searched and bumped an old thread...

Did we say that the RX front swaybar was 18mm? My XT (4cyl 4WD with air ride) has a 19mm front swaybar and it plows horribly. If we can confirm that the RX has an 18mm front swaybar, then I will post a thread in the Marketplace asking for one...

Thanks guys :)

#24 All_talk

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Posted 01 April 2005 - 03:25 PM

Here's the chart:

Posted Image

In stock form the RX (and most cars) tend to understeer, as stated before in general this is safer. So if your not making other changes like spring rates, then leaving the front alone and add a larger rear makes the most sense. The stock front (18mm) with the XT6 rear (20mm) should be a good combo.

Gary

#25 DerFahrer

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Posted 01 April 2005 - 03:57 PM

Thanks a bunch for the chart though, Gary! That helps out a lot! :)

But do notice that my 4WD XT with air ride has a 20mm rear bar already, which is the thickest of the bunch... So I'll just leave that.




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