Suspension Theory/Chat Thread

[Highrev1]

Ok Since we see so many of the same questions asked I thought we should start up an "open" thread to discuss suspension theory and tuning.

And I love seeing more people in this area than the "other" area That area means nothing without suspension.

Since I started this thing, How many of you when you pull out of a street and turning even if you pull out normally hear the inside tire not really spin but struggle for traction? I know it happens to me even when I am being careful and trying not to do it.

[SR20DE_MAN]

You speakith my language my fellow handling junkie. *Suscribes.* I'll be back in as soon as I pick up my Si sedan. I plan to make that little car stick to the tarmac like gum sticks to hair. Almost to the point of knocking me out cold when I turn. You know. Kinda like F1, but without the grooved tires! Hahahaha! (^o^ ) <3

[Highrev1]

I know that feeling where you take a turn so hard that the you have to tighten your whole body from the G's, one time I pooped a little.

[OMGWTFBBQIMDEREK]

Originally Posted by Highrev1

I know that feeling where you take a turn so hard that the you have to tighten your whole body from the G's, one time I pooped a little.

haha so any suggestions on fixing this little situation?

[Highrev1]

This one??--the struggle for traction?

The latter is easy slow down

[Nomar06]

I noticed lately when putting some power down the inside tire chirps a bit when turning. All-seasons have about 15k miles

[Highrev1]

Personally I think its a combination of a couple thigns First-The LSD Secondly the stock front sway bar. The Lsd cause it will acutally create more understeer than without one, It will allow for more power put down also, so that is a trade off. The bar cause the front is so tightly sprung do to that large bar causing inside "wheel spin."

[blue1]

It is really hot outside today.

[Highrev1]

I just came back in from painting I can't take it, its just tooo hot. Bad for tires, easily overheated.

[iomatic]

well, greg, if it's any consolation, i'm going to mod outside in.

That is: tires, poss. wheels, pulleys, (where. is. comptech.), exhaust, cat, mani, header, intake and hopefully a RS SC .

I'd like to think that's where you want to work on; the suspension to handle future mods. I'm still confused about which currently manufactured parts of the exhaust system will work on the si sedan tho (which part i have to wait for).

[Highrev1]

I would do it like this personally.

1. Tires
2. Proper alignment (not an OEM one!)
3. Dampers
4. Springs
5. Anti-roll bar or bars, depending on your springs

[mattsbobo]

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[cojaro]

I'd like to know more about dampers and springs (not separately; how they work together and the effect of different spring rates and different damper rates)

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[bossman]

ok,so here are my questions for the suspension guru's out there.

1.Would it be a good idea to replace the stock LSD with an aftermarket one,and if so what type(i.e. clutch,helical)?

2.Is there any company out right now making double adjustables for the Si?

3.Assuming that I am advised that an aftermarket LSD is a good thing what should I get?(1 way,1.5,2)?

4. Would it be better as far as sway bars are concerned to buy a bigger rear or to install a smaller front if I want to rotate easier but not snap oversteer?

5.Where can I get a good alignment or what would the specs be on a good alignment for an Si?

[Andrei'sCivic]

I'd just like to add I too would like to know more about dampners and springs work and how they work so well on BMW's. Anyway, my friends car just made my LX Civic seem like it handled like an F1 car.
-He drives a 2000 Toyota Corolla VE. It has 50,000 miles on it. I just installed an ebay strut bar on his car. The only other modification he had were 17" rims with low profile tires. I drove it after the instalation and I must say I can undestand how he felt when he said he felt an improvement.
-However his stock springs were very soft and his dmapners were even softer. His stock spring rates are around 150 lbs./in up front and 130 lbs./in in the rear. I was so amazed at how much sway and body roll he had, even after the instalation of the front upper strut bar. The worst I had ever experienced, I mean I had never driven a car with a softer suspension and one with so much body roll; made my car which has a stock suspension, upper strut bar rear Si sway bar and 18" tires feel like a race car.
-What is the worst handling car or what car do you think has the softest suspension and handles worst?

[bossman]

Originally Posted by Andrei'sCivic

I'd just like to add I too would like to know more about dampners and springs work and how they work so well on BMW's. Anyway, my friends car just made my LX Civic seem like it handled like an F1 car.
-He drives a 2000 Toyota Corolla VE. It has 50,000 miles on it. I just installed an ebay strut bar on his car. The only other modification he had were 17" rims with low profile tires. I drove it after the instalation and I must say I can undestand how he felt when he said he felt an improvement.
-However his stock springs were very soft and his dmapners were even softer. His stock spring rates are around 150 lbs./in up front and 130 lbs./in in the rear. I was so amazed at how much sway and body roll he had, even after the instalation of the front upper strut bar. The worst I had ever experienced, I mean I had never driven a car with a softer suspension and one with so much body roll; made my car which has a stock suspension, upper strut bar rear Si sway bar and 18" tires feel like a race car.
-What is the worst handling car or what car do you think has the softest suspension and handles worst?

If you just installed a stut tower bar( if that is what you mean) then his car would still roll,all a tower bar does is stiffen up the front between the left and right side,kinda like a sway bar for chassis flex..I would have to say just about any old vehicle with leaf springs is a beast to try an handle..predictably.

[bossman]

Well,since I asked some questions,I figured I'd contribute some knowledge too.

SWAY BARS: Sway bars are hollow tube or solid bars that connect either side of your suspension from left to right in the front and the same in the rear.Sway bars act like a spring in between the left and right side suspension by resisting any change in compression difference between sides.This is part of the reason that cars with stiff springs and rear sway bars will pick up a tire during hard cornering.Generally stiffer front sway bars will induce an understeer condition and a stiffer rear sway bar will allow the vehicle to rotate easier during turning.It should also be mentioned that while the sway bars resist the difference between left and right sides they will have no effect if both sides of the suspension make the same compression at the same time and distance.

I will fill in more info later as needed.

[Highrev1]

Originally Posted by bossman

ok,so here are my questions for the suspension guru's out there.
1.Would it be a good idea to replace the stock LSD with an aftermarket one,and if so what type(i.e. clutch,helical)?
2.Is there any company out right now making double adjustables for the Si?
3.Assuming that I am advised that an aftermarket LSD is a good thing what should I get?(1 way,1.5,2)?
4. Would it be better as far as sway bars are concerned to buy a bigger rear or to install a smaller front if I want to rotate easier but not snap oversteer?
5.Where can I get a good alignment or what would the specs be on a good alignment for an Si?

I wouldn;t do anything really first take the car to 5-10 Autocrosses and learn to max it out in its stock form then change what you want to make it handle how you want.

1. No need right now wait and see what the car is doing and if you feel that is needeed.
2. You can order custom Koni's or Moton's, unless your doing competition they are a waste.
3. This depends on quite a few things. Camber settings tires you run, driving skill
That also depends on what the car is being used for.
4.Generally any good place that does alignments can set them to what you want.
You will need 1 or 2 sets of front camber bolts, and a rear camber kit to adjust the alignment on this car

[Highrev1]

Originally Posted by Andrei'sCivic

-However his stock springs were very soft and his dmapners were even softer. His stock spring rates are around 150 lbs./in up front and 130 lbs./in in the rear. I was so amazed at how much sway and body roll he had, even after the instalation of the front upper strut bar. The worst I had ever experienced, I mean I had never driven a car with a softer suspension and one with so much body roll; made my car which has a stock suspension, upper strut bar rear Si sway bar and 18" tires feel like a race car.
-What is the worst handling car or what car do you think has the softest suspension and handles worst?

Body roll is no indication of how well or poorly a car handles. Also Stiffer is NOT better, In fact almost the opposite. Read throught the suspension sticky at the top of the page as to why

[Highrev1]

Originally Posted by cojaro

I'd like to know more about dampers and springs (not separately; how they work together and the effect of different spring rates and different damper rates)

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Saved the best for last Well the question I liked best :0

"All springs "Bounce" its in their nature. Dampers Control the springs Occilations (bouncing). So if your car is bouncing, its not the springs fault its the dampers fault. To stop them from making the ride bouncy you need the proper damper (shock)."

That is why after a while with lowering springs your car gets bouncy if your on stock shocks. Much unlike common mis-belief Shocks don't just blow, it is a slow degreagation over time. That is why almost always older cars bounce down the highway if they haven't had their shocks replaced. It can also give you that FLOATY feeling on the highway over bumps, dips, and irregularities in the road.

"There's alot more to a damper then just the materials.... theres differences in valving, High shaft speed valving, Mid shaft speed valving, Low shaft speed Valving... Each one influencing different aspects of the damper. Low shaft speed valving deals mostly with how quickly weight gets transfered around the chassis, thus influencing the cars handling balance. High shaft speed valving deals more with how the damper deals with impats, bumps and such, so it deals more with the dampers Ride characteristics. Mid shaft speed valving deals with a bit of both. Tie that in to both Bump and Rebound differences.... and that gives you at least 6 different "tuneable" parts on a damper that influence handling and ridequality.

So you can see that the valving a damper has, not just the materials its made of, are very important to the cars ride and handling balance. (this is primairly why I don't trust those "cheep" coilovers... too little info dealing with the dampers)" And what is out there isn't that promising I have seen shock dyno's from both and Koni's appear to be the most performance oriented.Tein's or any of the "pre-built" coilovers for example DOn't flame me for not likeing them sorry guys.