OK, guys I need your opinion on this.

I will be running a 500 in/lb on the front of the 200SX race car and 400 in/lb on the rear with the True Choice double adjustables that were rebuilt to handle these rates.

I am also running a rear ST Bar 3/4" (19 mm) thick. The rear has a toe-in of 1/16 and 1.2 negative camber. the front has 2.7 negative, 1/8 toe-out, and 3 caster

Prior to this set-up I had a 450 in/lb front and 375 in/lb rears. I had the same rear ST bar and I was running the front 1.10 inch (28 mm) ST bar.

I switched back to the front hollow stock 1 inch (25.4 mm) sway bar.

The ratio of front to rear springs is still the same, ie, the rear springs are 80% of that of the front. Before they were around 83%.

I have read that people get better trun in with a stock bar and rear ST bar. But that is on the Classic and the classic has a 1.10 inch front stock bar that is most likely solid.

I cannot drive the car since it is not streetable.

What impact would this set-up have on the handling? Would I get "massive" oversteer?

All opinions are welcomed.

I have a 300/200 on my car with a adjustable rear stillen bar and the factory front bar. I am seriously considering going to the 300/300 combo and then using a thicker front bar. I would then adjust the rear out to get the right balance. Right now the rear bar is full soft. With the stiffer rear springs and a stiffer front bar I think I would still have the same basic handling balance as now just less roll all the way around.

The front bar on a classic is not solid. You should free the car up a lot goin to this setup. Geo should chime in on this;)

Originally posted by 98sr20de
I have a 300/200 on my car with a adjustable rear stillen bar and the factory front bar. I am seriously considering going to the 300/300 combo and then using a thicker front bar. I would then adjust the rear out to get the right balance. Right now the rear bar is full soft. With the stiffer rear springs and a stiffer front bar I think I would still have the same basic handling balance as now just less roll all the way around.

I have been thinking about the Stillen bar. What is the exact diameter? If I remember correctly, it was thicker than the front ST bar which is 1 inch (28mm). I do not know if that is advisable on a road course at high speeds. I would love to try it and see how the car handles. At $239, I cannot afford to buy it and have it not work on the car. Please tell me the exact diameter if you can. Stillen does not list it on their web page.

Originally posted by james vick
The front bar on a classic is not solid. You should free the car up a lot goin to this setup. Geo should chime in on this;)
Do you know if the stock classic sway bar will fit on the 200SX?

The Classic has a 28 mm stock bar and if as you say it is hollow, it should provide less stiffness than the ST bar for the 200SX.

I'm running AGXs with GCs with 325/325. I have the stock front bar, and the ST rear bar. I also have the N-tech control arm brace, and front ES bushings. Going from the 200s to the 325s in the rear, took alot of the understeer out of the car. Before, at autocrosses, I would have to put the rear shocks at 8 to get anything that is close to rotation. With the 325, I had the same shock settings, and the car was very light in the rear thru off-set gates. I turned the shocks donw one notch each run, and settled on 5. This was also with 205-50-15 Kumho V700s.

Originally posted by nj1266


I have been thinking about the Stillen bar. What is the exact diameter? If I remember correctly, it was thicker than the front ST bar which is 1 inch (28mm). I do not know if that is advisable on a road course at high speeds. I would love to try it and see how the car handles. At $239, I cannot afford to buy it and have it not work on the car. Please tell me the exact diameter if you can. Stillen does not list it on their web page.

The Stillen bar is 29 mm or 1.15 inches. I used my dial calipers. It is also hollow. The tickness is not the best thing to go by. This bar has two mounting points for the bar as part of the adjustment. It also allows you to slide the bar up and down the rear arm a significant amount. Both these features allow you to adjust the bar. The mounting points are what really determine the stiffness of this bar.

QUOTE]Originally posted by eric96ser

I'm running AGXs with GCs with 325/325. I have the stock front bar, and the ST rear bar. I also have the N-tech control arm brace, and front ES bushings. Going from the 200s to the 325s in the rear, took alot of the understeer out of the car. Before, at autocrosses, I would have to put the rear shocks at 8 to get anything that is close to rotation. With the 325, I had the same shock settings, and the car was very light in the rear thru off-set gates. I turned the shocks donw one notch each run, and settled on 5. This was also with 205-50-15 Kumho V700s.[/QUOTE]

The B15 suspension from progress group uses a similiar setup as Eric. Even rates front and back. Our cars have basically the same setup as the 2.0 B15. I really believe that if you used the Stillen rear with a even front to back rate that you could then use the ST front bar and set the stillen rear to near full stiff in back. If you want to make the front less effective at that point then use the oem bushings instead of urethane. From what I can tell my car with the Stillen bar set nearly full soft is very similiar to the ST rear bar. If you still crave more rear roll stiffness at that point then you could always box in the rear u-channel by welding some plate in there. That is what stillen did to the Maxima that they did. I have read in Grassroots Motorsports and SCC about several FWD race cars you stiffer rear springs then front springs. Something in the order of a F400/R500 on an ITR for instance.

With any non-oem front bar you better have a good LSD because the inside front tire will be more prone to spin due to the decreased load on the inside tire.
Here are some pictures of my rear bar.http://www.imagestation.com/album/?id=4291673267&idx=1. Clink on the album. There are multiple angles.

So Naji,

let me try to "parse" the number-fest you supplied us with.

Although the interaction between suspension components should not be overlooked, what you plan to do boils down to 2 changes:

1. You go 11% stiffer springs up front and 6% in the rear.
As you say this changes the ballance from your previous setup to 3% more up front. Although no texactly so, lets assume you will have 3% "more understeer".

2. You go from 28mm front sway to 25.4 front sway. 25.4 will be close to 50% lighter than 28.

(And YES, the classic front sway IS hollow. I cannot even imagine how a 28mm solid sway would feel on a classic!!!)

All other numbers, altough pertinent, do not enter your basic equation since they either remain the same or can be adjusted accordingly.

Since 50% is a substantial change, I can guess that indeed, you will have a pronounced oversteer, although not exactly "massive".

I think you will have to consider what you tried to accomplish with your previous setup when it was done. In some cases, spring setups are used to "counter-effect" an imbalance between front & rear sways. I think you had at some point main-tender setups with your Truchoice struts. The main-tender combination gives a low spring rate until the transition point so it is basically up to you to decide/describe how the car handled with your previous setup. Is the above assumption correct and are you now going with only 500-400 mains and no tenders?

I am positive that going to 500lbs up front will reduce the 50% effect of the swaybar to about half (i.e. it will be equivalent to ~30%). Unfortunately, I do not have any info on your previous setup behaviour in order to be able to "guess" on the "mass" of the oversteer of the proposed new setup.

Chris

Originally posted by hpro123
[B]So Naji,

1. You go 11% stiffer springs up front and 6% in the rear.
As you say this changes the ballance from your previous setup to 3% more up front. Although no texactly so, lets assume you will have 3% "more understeer".
That is correct.
2. You go from 28mm front sway to 25.4 front sway. 25.4 will be close to 50% lighter than 28.
I do not understand how you calculated the 50% lighter. By my calculation the stock bar will be 9-10% smaller. How did you get the 50%?
Since 50% is a substantial change, I can guess that indeed, you will have a pronounced oversteer, although not exactly "massive".
I still do not understand where the 50% number came from.
Is the above assumption correct and are you now going with only 500-400 mains and no tenders?
The tenders have been off the car for a long time. Even when I was running 450 fr and 375 rear, I had no tenders.
I am positive that going to 500lbs up front will reduce the 50% effect of the swaybar to about half (i.e. it will be equivalent to ~30%).
Why is that? I was under the impression that stiffer springs up front allow you to run a softer sway bar up front. So basically atiffer springs will compensate for a softer swaybar. If as my calculations tell me that my springs are 11% stiffer and the sawy bar is 9-10% smaller, then the car would tend to understeer less with the added benefit of better turn-in.

Diameter does not linearly correlate with stiffness. For a rough estimate check:

http://www.whiteline.com.au/docs/010barup.pdf

Note that 25-to-28 mm on the table is ~57% (everything else been equal, i.e. both solid or both hollow and similar "hollowness").

Did not know about your straight main spring setup, this certainly makes it easier for you to infer the effect of other components. BTW, why did you discard the main-tender setup?

As for the last part, this is exactly what I am saying. Your stiffer front springs will (to some extent) negate the effect of going with a lighter front sway, i.e. they will allow you to go with the 25.4mm sway and the effect will not be as pronounced as it would had you not stiffen the front prings (with my numbers you would not get the effect of a a 50% lighter sway, it would be more like 30% lighter).

Our only "difference" is the 50% I used from the link given above. And I know it is accurate Naji.

Chris

Originally posted by hpro123
[B]Diameter does not linearly correlate with stiffness. For a rough estimate check:

http://www.whiteline.com.au/docs/010barup.pdf

Note that 25-to-28 mm on the table is ~57% (everything else been equal, i.e. both solid or both hollow and similar "hollowness").
That is a great table. Just what I wanted. Thanks a lot Chris. Now I have yet another tool to tweak the car with. I bookmarked it. I suggest all of the otehrs do the same.
Did not know about your straight main spring setup, this certainly makes it easier for you to infer the effect of other components. BTW, why did you discard the main-tender setup?
The series that I am running in does not allow for a tender springs.
As for the last part, this is exactly what I am saying. Your stiffer front springs will (to some extent) negate the effect of going with a lighter front sway, i.e. they will allow you to go with the 25.4mm sway and the effect will not be as pronounced as it would had you not stiffen the front prings (with my numbers you would not get the effect of a a 50% lighter sway, it would be more like 30% lighter).
To play it safe, I will take the ST bar with me to the track. I will drive the car during practice with the stock bar. If I like it, I will kep the car as is. If the car is hard to control, then I will switch back to the ST bar.

One more question. Do you know if the Classic stock bar will fit on the 200SX?

I recently switched back to a stock front bar on my Classic and the car rotates much better. The stock bar came off a NX2K and I swear I don't think it's hollow. Are the NX and Classic bars different? Are you certain the Classic bar is hollow cause the one I put on my car sure didn't look or feel it.

I still think you should go even rates front to back.

Originally posted by nj1266

That is a great table. Just what I wanted. Thanks a lot Chris.

No problem Naji. I learned the hard-way when I tried a "slightly" smaller custom adjustable! It was like it wasn't even there!

The series that I am running in does not allow for a tender springs.

Ok, I was just "fishing" for information on the behaviour of the tender-main combination relative to plain mains. :)

To play it safe, I will take the ST bar with me to the track. I will drive the car during practice with the stock bar. If I like it, I will kep the car as is. If the car is hard to control, then I will switch back to the ST bar.

Always prudent to have all options open.

One more question. Do you know if the Classic stock bar will fit on the 200SX?
Sorry for the "edit" but, I do not know. Never touched a 200SX myself and anywhere I have checked there is a different part number. So, I would not bet it will fit.

Chris

Originally posted by Shoes59
I recently switched back to a stock front bar on my Classic and the car rotates much better. The stock bar came off a NX2K and I swear I don't think it's hollow. Are the NX and Classic bars different? Are you certain the Classic bar is hollow cause the one I put on my car sure didn't look or feel it.
Were you running an ST bar in the front before the switch? What were you running in the rear? I think the bar on the NX and the Classic are the same. As for the hollow vs. solid, I have read of some people saying they are hollow and others saying they are solid. At this point I will remove the stock bar on my Classic and check for myself.

Originally posted by nj1266

Were you running an ST bar in the front before the switch? What were you running in the rear? I think the bar on the NX and the Classic are the same. As for the hollow vs. solid, I have read of some people saying they are hollow and others saying they are solid. At this point I will remove the stock bar on my Classic and check for myself.
I was running the ST bar. Current set up is as follows:

Stock front bar with ES bushings.
Nu Tech rear bar on middle setting.
Nu Tech lower control arm brace.
Stillen STB
Shocktek coilovers with 300f/250r ERS.
Shocktek custom rear pliiow ball mounts (only 4 sets ever made)
Cusco camber plates with custom hardware by Shocktek
ES bushings throughout.
205 Kuhmo Victoracers on 15 x 7 Volk TE-37's

I'm running softer springs than many because the car used to see regular roads in the summer months. Now that it's more of a track whore I plan to up my spring rates to 400f/350r as a starting point. I don't buy into the equal rates f/r, at least not for my driving style and handling preference.

Let me know if the stock bar is indeed hollow.

Originally posted by Shoes59



I'm running softer springs than many because the car used to see regular roads in the summer months. Now that it's more of a track whore I plan to up my spring rates to 400f/350r as a starting point. I don't buy into the equal rates f/r, at least not for my driving style and handling preference.

Let me know if the stock bar is indeed hollow.

I think it is somewhat B14 thing as I stated in my earlier post. Also, this is my thought. if you can use the stiffer rear springs (ie equal front back) to help the car NOT understeer then you should be able to put the stronger front swaybar on and NOT have the excessive amount of understeer that you mentioned. Lend/sell me your 300 front and I will try it out.

Originally posted by 98sr20de


I think it is somewhat B14 thing as I stated in my earlier post. Also, this is my thought. if you can use the stiffer rear springs (ie equal front back) to help the car NOT understeer then you should be able to put the stronger front swaybar on and NOT have the excessive amount of understeer that you mentioned. Lend/sell me your 300 front and I will try it out.
The B14 has a 1/4 inch of toe-in for the rear suspension. That is a LOT. This is where the understeer and lack of rotation is coming from. That is why you are forced to run same rat springs all around. The simple solution is to bend the rear beam and keep 1/16 to-in only. If you autoX, then bend the rear to 0 toe. Road racing requires a bit more toe-in for the rear for high speed stability.

My previous suspension set-up was great and I loved it. But I like to tinker and change things to try and make them better. That is why I want to run the front stock bar with stiffer springs all around. Next I will be trying a 450 spring in the rear instead of the 400. Tuning a suspension is more art than science, what works well for one person is downright ugly for another.

I am hoping that by reducing the stiffness of the front bar by 30% (as Chris mentioned) I will make the car rotate even better than before. The only way to test this is on the track. I will soon find out July 13-14 is around the corner.

The B13 bar is hollow and a little bigger than a B14 bar. The B13 ST front bar is HUGE and mounts under the control arms. The B14 ST front bar is the same size as the stock bar, but soild and fits over the control arms like stock. I'm not sure if you can swap the B13 bar onto a B14, because the control arms are closer together on a B13. A few years ago I tried to put a B13 ST front bar on my '96, and it ddn't fit. I never tried the stock one.

Originally posted by nj1266

If you autoX, then bend the rear to 0 toe. Road racing requires a bit more toe-in for the rear for high speed stability.

Tuning a suspension is more art than science, what works well for one person is downright ugly for another.


I'm running zero toe all around with 2.5 degrees negative camber up front and 1 degree negative in the rear. I don't claim to be a great driver and have had little opportunity to tinker with different set ups. However, the car handles great, very stable at high speeds, very neutral even in the sharper corners (keep in mind I consider myself an excellent trail braker) and inspires a great deal of confidence on track.

Your statemnet about tuning a suspension being an art is spot on. What's good for one driver may be awful for another. There is no right or wrong, just baselines to work with.