Front strut tower bar, rear, or both....

[Guest bastaad525]

I've already upgraded my suspension with Eibach springs and Tokico shocks... a moderately stiff setup, seems to grip well, the car has more grip and better handling than any other car I've driven that's for sure. Even with this setup the roll or lean that the car does when cornering sharply still seems to be excessive... I dont know if it's the body flexing or just the suspension not holding the car down enough. The car feels kinda 'floaty' in corners is the best way I can describe it. Next I'm looking at installing one or both of the strut tower roll bars or whatever they're called and was just wondering what would be best, front, rear or both? I haven't really pushed the car too hard, so I can't say for sure, but if I had to 'guess' I would say the car definately leans more toward oversteer, though I've never once had the rear step out on me (again... I haven't ever pushed it TOO hard) I can get one or two tires singing a bit if I take a street corner (45* bend) going over 20-25mph. I guess the main thing is I just want the car to seem more 'planted'... I want it not to lean so much in turns, but to stay more flat to the ground....

 

So which rollbar(s) placement should I use? By the way for what it's worth I'm looking at the bars that MSA sells for like $100

[RedNeckZ]

Go with the front brace first and add the back later. It will help a lot. You would not believe how much your front shock towers will bend in during hard cornering. It helped my car a lot adding them both. Good luck, Rich.

[rc's240z]

well what your describing is a handling problem. I would suggest that you talk to a suspension specialist prior to spending more money on bolt on parts that will help, but not solve what you are experiencing.

 

there are several threads on line regarding strut bar solutions and what they will do for you and your car. I suggest that you review those posts to make an educated decision.

[Guest DISCUS]

I reccomend both, however it would be easier to respond if spring rates`were given and your car weight, front/rear ratio was known as well.

It pays to experiment with different spring shock setups if possible. An alternative is to provide the above information to the forum and check the responses from experienced members.

[TimZ]

Assuming I understand your intent correctly, I'd have to say that the strut tower braces are going to have minimal (if any) effect on your body roll characteristics. You should invest in anti-sway bars (maybe that's what you meant?) long before worrying about tower braces.

 

Since you are already using a pre-packaged solution for your spring rates and shocks, I'd just go with something similar for the sway bars, and you need to get them as a set. Also, don't go overboard with the bar sizes, as the really stiff front bars will eventually tear your frame rails apart unless you do a significant amount of fabricating reinforcements.

 

Also, do you have fresh poly suspension bushings? These will also make a much bigger difference in handling than a strut tower brace could ever dream of.

[zguy95135]

heres a "strut tower brace" that rc's240z sells.

http://www.pdkfabrication.bravepages.com/240%20front.htm

im going to get one for myself later, that thing's awesome

[TomoHawk]

YOu can make your own stress bar from 3/4"O.D. ubing. You only need to flatten the ends in a press, or maybe with a hammer, then drill holes for the bolts. Double-check things before drilling, as you might need to offset the holes for clearance reasons. The front miight need to have an arch or something to go over the engine. Check things first.

[rc's240z]

Our strut brace is a good option especially if you are looking to install aftermarket sway bars. Since our strut brace solution includes an easy solution to protect your frame rails.

 

To "fix" your handling question I would be looking at the mechanics of your suspension, your chassis is part of that. Looking at your spring rates and swaybars would be the place to start.

 

Our strut bar will help tie everything together. We see that our solution will add enough support to the front of your Z that it can create an understeer situation, your experience may vary significantly based on the condition of your chassis.

 

Tomohawk: a single bar between the strut towers will do very little to support the chassis of a Z. This is an option but not one I would suggest. For more information please review previous postings on strut braces.

[TomoHawk]

I see you have gone one step better than just the plain strut bar. I assumed Bastaad was referring to the strut bar like I described. If a simple strut bar is so bad, why is everybody using them? Like all the aftermarket sport companies.

 

I don't know what Bastadd's final goal is, but it sounds like that 'triangulated' system suggested might be overkill. Sounds like something better used in competition. The homemade strut bar suggested is the same thing that MSA and others sell, just not as fancy.

[rc's240z]

I am sorry Tomohawk, I came across a little strong.

 

Please understand that requirements set out by the SCCA limit strut braces that you can install on your car to just a cross bar for most autocross classifications. For some cars that is fine. For Datsun Z's they are not.

 

I think that we can agree for most applications that these "aftermarket" strut braces are 95% cosmetic 5% usable. A cross bar is not a universal handling solution for every rice rocket you see, but they all have them..

 

In my opinion the MSA bar is automotive jewelry, I had one on my car for several years, it made no difference how my car handled.

 

Our friend who made this original posting is looking to make a difference in how his car handles. A bent tubular bar between the strut towers with a single anchor point will make a minute difference in how his car responds. Although given the choice between your solution and MSA's solution, I would prefer your's.

 

You will note that our solution is modular, he can buy the parts he wants. If he wants or build his own solution, he can. Again my first suggestion is to look at other parts of his suspension to fix his problem....

[zguy95135]

so is your bar legal for SCCA autox? (prepared class)

[TomoHawk]

I understand, and agree.

[Guest bastaad525]

I have no idea what the spring rates or any of that stuff is....

 

The springs are eibach pro kit, and the tokicos are just plain tokico gas shocks. To be honest I never really put much thought into making the car handle until now... I always had the "go fast in a straight line" mentality, but then realized that this car is really fun to toss around in the corners (which I found it actually handles quite well... way better than any other car I've had so far, including 3 280ZX's that had upgraded suspensions... the thing just seems to me to stick really well... only problem I have is that it leans too much), so I want to pursue that. I'm glad you mentioned about what can do damage to the body of the car... that's always been a thought in the back of my head, I figure it wouldn't take a whole lot to add enough stress to the body to start cracking it.

 

I haven't replaced the bushings yet, and yeah they are pretty bad. I guess I never considered them as a big factor in how the car handles... again... I never really gave much thought to handling at all, and really now that I am, I dont know the first thing about what makes a car handle well. I know that the few times I looked the poly bushing sets weren't too expensive, but how about getting them installed? Anyone have an idea as to how many hours of labor is involved with replacing all the bushings? This would definately NOT be a job I could do myself at my apartment. I'm sure it's something I wont be able to do any time soon, but it would be good to know about how much $$$ to have put aside before I get ready to have it done.

[rc's240z]

My understanding is that if you are running street modified that you can run our complete solution. Since our bar is a modular solution you can remove the parts that would not be considered legal in your class.

 

Since I do not have the specifics for each class handy I cant speak to which class allows what.

 

BSP only allows a cross bar and that was my reference in the comment above.

[rc's240z]

Bushings, swaybars, spring rates all tie together. I would suggest that you see the guys at top end performance. They are up in your area and should be able to help you sort out your handling issues.

 

Just dont buy their strut bar...PDK fabrication's strut brace is the only way to go. Not that I am biased or anything...lol

[Guest bastaad525]

I really hate dealing with the guy over there at Top End....

 

 

my main question hasn't been answered yet though, if the car sticks well, and has a moderately stiff suspension setup already, what part/parts is/are responsible or are the MOST responsible for keeping the car from leaning too hard in a turn? I always thought that this was 99% a function of the springs and shocks... stiffen them up, get rid of the leaning. Then I replaced those and still the lean, and you (rc240z) are saying that a strut tower bar will not solve that.... I can see how bushings would affect handling, stability, and the cars general vibrating around at speed... but I dont see bushings playing a big part in 'body roll' if I'm even using the right term to describe that... basically the side of the car that is the same as the direction I"m turning raises higher, and the side opposite the direction I'm turning sinks... I know the shocks and springs are relatively stiff (trust me... every bump on the road reminds me of this!!) so I'm just wondering which part is the next major part that affects this...

 

CAN bushings be the cause for excessive rolling?

 

 

Also, you hold that the regular strut tower bar has little to no effect on handling or body rigidity... why do so many people swear they feel a huge difference after installing one?

[TimZ]

I really hate dealing with the guy over there at Top End....

 

...Then don't. I've heard enough stories from people whose opinions I trust that I really don't have much faith in anything he says. He doesn't have anything that you need that you can't get elsewhere anyway' date=' so why bother?

 

my main question hasn't been answered yet though, if the car sticks well, and has a moderately stiff suspension setup already, what part/parts is/are responsible or are the MOST responsible for keeping the car from leaning too hard in a turn?

 

Ummm, yes it has been answered. ANTI-SWAY BARS. That is specifically what they are there for. It's their job. Strut tower braces will not do diddly for your body roll.

 

CAN bushings be the cause for excessive rolling?

 

If your anti-sway bar and/or end link bushings are bad this could definitely have an effect.

 

Body roll issues aside, your suspension bushings will have by far the most noticeable effect on how your car feels and handles, especially if your old bushings are shot. You should not be screwing with anything else if you have bad bushings - it's simply a waste of time and money. I can't emphasize this enough.

 

Yes, it's pretty labor intensive and you will probably end up spending a fair chunk of change if you have someone else install them for you, but without them your other mods will be pretty much pointless.

 

 

Also, you hold that the regular strut tower bar has little to no effect on handling or body rigidity... why do so many people swear they feel a huge difference after installing one?

 

Probably mostly because they just spent a pile of money on them, and they really want for there to be a difference.

 

The strut tower bars will help provide some additional body rigidity - even the single bar type. It's just that if your unibody is in good shape already it gets pretty difficult to quantify how much they are helping - I seriously doubt that there are more than one or two people (if anybody) on this forum who could tell the difference that anybody's strut tower brace makes in your current setup in a double blind test.

 

If you have a super stiff suspension (WAY stiffer than the Eibach setup) with huge anti-sway bars, then you will see more benefit from a setup like rc240 is offering.

[Guest bastaad525]

...Then don't.

 

Trust me dude... I don't

 

TimZ - kewl thank you for the clarity in your repsonse okay... roll bar is out, bushings just got moved up to #1 priority when i start working on suspension, and with them some thicker anti sway bars... that should do it? Sounds good, and thank you guys for pointing me in the right direction yet again

[jkube]

Bastaad525,

 

I would also reccomend to first change the all the bushings to poly bushings or in a couple of spots- aluminum.

 

Just this change alone will improve the response in steering and make tossing the car around a complete joy (and addiction!!!). The parts that can be made from aluminum instead of poly is the steering coupling and the front tension/compression rod coupling to the frame.

 

The next thing would be to put on larger sway bars. probably 1-1/8" on front and 7/8" on the rear. This will prevent body roll.

If you have some speed shop fabricating contacts, the bars can be made from "Stress-proof" bar.

Use rod ends to hookup to the bar (drill holes into the bar near the ends) and use the poly bushings at the control arm end.

 

Lastly, redo the bump steer on the front end. This is best done by removing the front lower control arms, redrilling the mounting holes in the cross brace approx 3/4" above the existing ones, welding in some washers to beef up the bolt hole area and reinstalling the control arms.

 

Once again though this would better be done by a shop in your area.

Doing this kind of work in your apartment area is not impossible, just not very much fun.

 

I did all the work mentioned above on my car, and when I installed strut bars on both front and rear, I wasnt sure if I noticed any difference. I really tried to find justification in buying the bars, but quite honestly I couldnt tell the difference, even on the track.

 

The biggest noticable difference came from the poly bushings and sway bars. Go with those pieces first. The bump steer changes improved high speed stabilty on the highway, you dont have to do this but it does help.

[TimZ]

TimZ - kewl thank you for the clarity in your repsonse okay... roll bar is out' date=' bushings just got moved up to #1 priority when i start working on suspension, and with them some thicker anti sway bars... that should do it? [/quote']

 

That is what I would do. You might want to try just the bushings with your existing anti-sway bars first - sway bar bushings are usually part of the set, and the increased response from the new anti-sway bar bushings and end links might give you enough improvement for what you want.

 

Maybe it's my old age, but I've become a big believer in not going overboard with suspension stiffness on the street. Some increase in stiffness is generally necessary, but it's pretty easy to go too far. Stay with the softest setup that gives you the handling characteristics that you want and you'll be much happier in the long run.

 

BTW, the 1-1/8" front bar will be big enough to require reinforcing the frame rails, in a manner similar to what rc240 does with his strut tower bar.