Write-Up: Front/Rear (Addco) Stabilizer/Sway Bar Installation

charlieRobinson wrote:

I wanted to do just the rear first and see what kind of difference that makes in cornering alone. And then move to a front bar if needed. I absolutely must neutralize the full on understeer I have now. Hate it.

Is your front end still sitting high?

I think its back to OEM specs now but it might be a centimeter or 2 higher than normal at most if it is. How are you supposed to measure? From the center of the wheel to the bottom of the center point of the fender?

I get some vibrations on the gas pedal when I go over 70mph but seems to smooth out when I accelerate. I read that if your front is high it causes the front wheels to 'bounce' creating vibrations. Not sure if that is what it is or if it's something else or nothing at all.

The front bar is the one to do first. You will be able to feel the front more I'd say. The Riviera will never be a slot car (with the exception of Robo's car), but the 2 Addco bars I installed made a world of difference in road holding ability. FWD cars inherently understeer. The Addco bars made a huge difference in my car.

I want to neutralize my steering or lean towards oversteer. From what I understand, a fatter rear bar will promote these results.
I want to be able to take corners like this, and adjust for oversteer. A manual transmission sure would help accelerating out of the corner though.. There is nothing better than dropping gear and punching it after taking that hard turn. MMM MMM GOOD.

Charlie,
You'll need to do a lot more work to the Riviera than sway bars. The Riviera was not engineered to be that type of car. The Addco bars will make a big difference, but it won't make it into a canyon carver. The reason that auto manufacturers engineer understeer in to cars, is because it is safer. The typical reactions that people have, at the limit, are the right reactions. They slow down which gets the car back under control. If you hit the brakes on a car that is oversteering, it oversteers worse, and you spin out of control. I'm not aware of a bar for the Riviera that is big enough to do what you want. I think if you simply use the rear Addco bar with the stock front bar, it won't get you where you want to be.

Agree. Think about what sway bars actually do: transfer unsprung weight from one side of the axle to the other, through torsion. As a rule, stiffening the rear bar will increase front traction, but too much stiffness will sacrifice rear wheel traction (one rear wheel lifts), which causes exactly the effects Larry mentioned.

When one of the rear wheel lifts, the car's roll is entirely being controlled by the front sway bar. If it's not up to the challenge (the stock bar won't be), your rear end slides out. That's where you get the oversteer.

The video you posted is of lift-off oversteer, so named because the car needs to be loaded with front bias for it to happen. Lift off the throttle or trail brake in a turn, the tail will slide out. It is often violent and hard to recover from - aka snap oversteer - this is not the same as a powerslide, which is coming out of the corner with the rear end out. A FWD car will never powerslide, period, unless you are driving in reverse. If you modify a FWD car for oversteer, it will be snap oversteer, not a controllable powerslide.

My car oversteers on some situations, but in other situations it plows, and sometimes it's completely neutral. It depends on the conditions and how you drive the car. I can take any stock Riv and induce snap oversteer by entering the corner, turning hard and braking. It sucks. If you beef up both front and rear bars, you'll minimize roll of the entire car without encouraging snap oversteer much. If you just to the rear bar, you'll induce snap oversteer much more easily. You will not ever achieve a proper powerslide.

NASCAR 3-part bars are very rigid because they're made for high-speed continuous oval tracks, not daily driving on public roads. They might give you additional grip, but when the limit is reached, you could spin out easily. This is because 1-piece bars flex more and so have a more gradual spring rate. NASCAR bars have an extremely high spring rate, and are not so forgiving. Dirt track racers use no sway bars at all, because this makes for better traction over a more uneven surface.

Whatever you do, be careful. winter weather is coming. If you want to know what an extremely stiff rear bar is like, when the first snow comes, put a pair of dedicated snow tires on the front wheels only. This will give you the extra traction up front, and your rear tires will slide out easily. I'M KIDDING OF COURSE - DON'T DO THIS. But it would be a good experiment to show you what can happen when you stiffen the rear bar too much.

Funny you say that... I have already been scoping out this year's practice parking lots...

I bought an Addco rear sway bar, but I still need to buy the bushings to install it. I will be installing it this summer. I don't know if I want to do the front addco bar, because of low funds and difficult install. I (at least for now). So would the a front strut tower brace help to even out the balance of the steering? I don't want to have too much oversteer after installing just the rear addco bar.

Hey where'd you get the strut race and rear away bar! Sorry just alittle excited lol

Never enough auto is where I bought the rear Addco sway bar. I have not bought a strut tower brace yet. I may actually make one with a friend who welds.

RidzRiv wrote:

I bought an Addco rear sway bar, but I still need to buy the bushings to install it. I will be installing it this summer. I don't know if I want to do the front addco bar, because of low funds and difficult install. I (at least for now). So would the a front strut tower brace help to even out the balance of the steering? I don't want to have too much oversteer after installing just the rear addco bar.

There is no way that you end up with over steer on the Riv by installing just the rear bar. The car will always under steer, but grip will be improved noticeably by installing front and rear bars together. I would concentrate on installing the front bar, difficult as it may be, first. That and the strut tower brace will give you the most noticeable change. I wouldn't even bother with the rear bar until you get the front in.

Okay, Can you give me any explanations of why I should tighten up the front before the rear? Won't that just create worse understeer?

RidzRiv wrote:

Okay, Can you give me any explanations of why I should tighten up the front before the rear? Won't that just create worse understeer?

I also have a 95 and I did the rear first. It definitely improved my ride.It did not cause any over steer at all.It improved the cars responsiveness everywhere.
I think the front bar on the 95 is hollow.I'm not sure as I haven't messed with it at all.
The theory is,according to front drive suspension experts,that a front drive lay out benefits from a stiffer rear bar rather than a stiffer front bar.A rear drive car is the opposite.
Driving styles and throttle control affect the cars attitude more than people think.I could get into a car specifically set up for someone elses style of driving and say" shit man you have under steer!" the other guy would say "No I dont! it's just right!" In the Riv's case it's difficult to create a monster since the Addco bars available are set up to OEM style.That means that Addco bars are,stiffer front bar and softer rear bar, WAY stiffer than stock.So..the car would still understeer but would need to be pushed alot Harder to exhibit understeer.See what I mean?

Thanks Robo. I plan on installing the rear bar soon, because I have it. I guess the weather will be nice enough to see if I need to buy and install the front bar before winter comes back. I don't want the tail end to be sliding around in the snow.

RidzRiv wrote:

Thanks Robo. I plan on installing the rear bar soon, because I have it. I guess the weather will be nice enough to see if I need to buy and install the front bar before winter comes back. I don't want the tail end to be sliding around in the snow.

I wouldnt worry too much about the tail sliding around. If you were installing a big beefy Nascar torsion bar then maybe? The bar will still give you a much smoother and controlable ride.Even at the limit.

Maybe think of it this way.

1) A stiffer REAR bar improves grip to the front axle (lessens understeer).

2) A stiffer FRONT bar improves grip to the rear axle (lessens oversteer).

3) Stiffer FRONT and REAR bars improve grip to both axles (decreases body roll).

So it depends on your goals. If you just want to lessen understeer, a rear bar will do that. Your Riv still won't oversteer easily, but it will have the tendency to kick out the tail in certain situations, like braking in a turn (be careful, this is dangerous). But just modding the rear bar won't decrease overall body roll of the car that much, because the front end is where most of the weight is.

If you want to actually increase grip (lat G) in the corners, you need to do both bars. Even though the car's behavior will return to understeering more, it will roll less and actually hold the corners better. Understeering isn't necessarily a bad thing, either. Some of the best handling cars in the world come from the factory with slight understeer built in; this is so the car is less likely to kill the driver when pushed to 10/10ths in a turn.

AA wrote:

For the rear bushings, only GM parts are a drop-in fit, but you can modify similar bushings (with firmer material) to fit. Mine are modified Ford bushings. Ford is known for using stiffer bars and bushing materials in their cars.
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Personally, I wouldn't use anything firmer with an Addco rear bar. As-is, the back end will come out (oversteer) in certain situations, especially in the wet. You should be careful upgrading only the rear bar, plus using hard bushings. It can make your car unsafe in a hurry, get you killed even. There's a reason almost every modern car comes with understeer built-in from the factory. It's not to make the car less fun, it's to help save you in the event you loose control in a corner.

It you decide to upgrade sway bars on the Riv, I'd do the full set, front & rear.

Didn't have a chance to digest all 25+ pages, but did check Addco's webpage and they only seem to have a bar for the rear for the 95. Is there a bar for the front of the 95?

Al

AA wrote:

Your Riv still won't oversteer easily, but it will have the tendency to kick out the tail in certain situations, like braking in a turn (be careful, this is dangerous).

TOKYO DRIFT!

RidzRiv wrote:

Okay, Can you give me any explanations of why I should tighten up the front before the rear? Won't that just create worse understeer?

I actually hated the way my Riviera handled with the stock bars. I noticed the problem more in the front than the rear. When we speak about understeer, it isn't really something you notice to a great degree until you really start pushing the car hard in a corner. I always found the front of the car would lean excessively, and it would get twitchy on a highway cloverleaf. This would be at what I consider normal speeds, I wasn't really pushing it. I installed the front bar first. It was a vast improvement over the stock bar for me. I also already had the STB. The car felt more controllable, and predictable at all speeds. I then installed the rear bar, and it got even better. The car is a joy to drive compared to what it was. IMHO, the front of the car needs more help than the rear. Adding the 2 Addco bars is one of the best things I have done to the car. The car definitely understeers less overall in normal driving.

Thank you guys for all of the explanations! I do plan on doing both bars eventually.

LARRY70GS wrote:

I installed the front bar first. It was a vast improvement over the stock bar for me. I also already had the STB. The car felt more controllable, and predictable at all speeds. I then installed the rear bar, and it got even better. The car is a joy to drive compared to what it was. IMHO, the front of the car needs more help than the rear. Adding the 2 Addco bars is one of the best things I have done to the car. The car definitely understeers less overall in normal driving.

You just sold me on this, Larry. The fact that you noticed an improvement AFTER the STB is what I wanted to hear. To me, the STB made a huge difference in cornering and straight line rideability. I wasn't sure how much better it could get after that, but it seems like it can get even better! Sweet!

Has anyone tried an addco 2015 in the back and an F41 up front? Based on 0 firsthand experience and only what i've read here, this combo plus the STS STB is what I think I am looking for.

Front Sway Bar P/N# 25649664 = F41 sport tuned '97-2004 PAU

charlieRobinson wrote:

Has anyone tried an addco 2015 in the back and an F41 up front? Based on 0 firsthand experience and only what i've read here, this combo plus the STS STB is what I think I am looking for.

Front Sway Bar P/N# 25649664 = F41 sport tuned '97-2004 PAU

Even if someone had, how would you determine which combination was better, without driving both cars? Not to mention all the other variables, tires, struts.

LARRY70GS wrote:

charlieRobinson wrote:

Has anyone tried an addco 2015 in the back and an F41 up front? Based on 0 firsthand experience and only what i've read here, this combo plus the STS STB is what I think I am looking for.

Front Sway Bar P/N# 25649664 = F41 sport tuned '97-2004 PAU

Even if someone had, how would you determine which combination was better, without driving both cars? Not to mention all the other variables, tires, struts.

There's no way to tell unless I buy them all and try out every combo. I aint doin that. Just gotta go with what I read and hope for the best. Same with springs, I'm not about to order 3 sets of custom coil springs, try them all out, and pick my favorite set. Gotta feel it out and hope it works out.

I have a used Addco front bar that came out of my '98 Riv. It has a little surface rust on some corners but can be cleaned up. I think I even have a whole front install kit leftover from Addco - all new (new but old?)...

$60 plus shipping? And don't ask me how much shipping is - I don't even have a box this big right now! I'm guessing $20 or so...

The thing is just kicking around my garage, in the way.