Stronger Suspension?, Suspension Options

[Dion]

I had a question on the pics forum and was guided to post a new thread. This was probably discussed before, but here goes... I have recently added new steel flares and larger rims(17x7and 8) Does any one believe because of this the susp. should be "BEEFED" up. I currenly have stock BOGE struts and 170# springs.The rims are secured to the original 4 bolt hubs. (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif) Cheers,Dion

[Andyrew]

Whatcha got on the fronts? (shocks, T bars, sway bar..)

What kind of engine?

Tires?

170 is alot.. If its stiff, then dont worry about it. If it understears or overstears and you want to change it... then OK.. if its perfect to ya.. then leave it!

[Dion]

Completley stock,,2.0l,. I'm still getting used to the feel. As I was on 5.5x15' for the past 15 years. I have not pushed the car yet to see it's limitations. waiting for the autocross season for that. (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

[Andyrew]

73 with a sway bar?
I would upgrade either the sway bar or the T bars or both when you have 170's in the rear. Thats shootin for some MAJOR oversteer. Can you say lift throttle oversteer? lol

A good known combo for stock cars is 140's in the rear, koni shocks all around, 19mm sway bar, and 19mm T bars (I think factory is like 17 on each.. forget) but a 21mm sway bar would be fine. Its all about gettin it "there" then doing adjustments. With more tire you CAN run more bar in the rear... but still.

Maybe downgrading to 140 lb springs would be best?

How stiff is the ride?

This is all my opinion. Im sure others will chime in.

[Dion]

The ride is not too harsh, maybe i'm just used to it. Refresh my memory regarding these beasts...I do not have any sway bars currently. Do you add a front only or a rear.I know you can do both but which one goes on if you only do one?. I fit is the front , can you do it without dropping the fuel tank. Would a top strut brace help a 914 without any swaybar? thanks (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif)

[dlo914]

IIRC i was told on the forum you should always install the front swaybar if you had one choice. instally only a rear swaybar would cause the rear to be too stiff and cause the rear to swing out on a hard turn. i too have no sway bars at this moment, but i plan to do a complete suspension upgrade w/ 19mm T bars & 19 or 22mm sway up front and bilstein adjustable strut perches in the rear & and maybe a stock rear sway bar....

[dlo914]

please correct me if i am wrong for i am still a NOoblet.... (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[Dion]

Thanks Daniel

[Andyrew]

Install a front if you dont already have one. You dont need anymore rear.

[dlo914]

QUOTE (Dion @ Mar 24 2005, 12:43 AM)

Thanks Daniel

you're welcome dion... (IMG:http://www.914world.com/bbs2/html/emoticons/type.gif)

[Brad Roberts]

There is NO need to install larger torsion bars... we have larger sway bars. I stopped selling the Weltmeister bars several years back when several other places gave us 24/27/31 mm bars. Spend the money on a larger bar.. it adds up to the same amount of money as if you bought larger torsion bars and the cheaper Welt bar. The difference: you will have a TON of adjustment with the larger bar.. but the overall ride will stay semi stock. Increase the torsion bars and the ride gets stiff.


B

[ArtechnikA]

QUOTE (Dion @ Mar 24 2005, 02:55 AM)

Do you add a front only ...which one goes on if you only do one? ...can you do it without dropping the fuel tank. Would a top strut brace help a 914 without any swaybar?

front only.

no, you hafta pull the tank, but it's NOT a big deal. good chance to replace the fuel lines in there that are probably 35 years old. it can be done solo but it's easier with help. make sure you get an antiroll bar kit that includes the inner reinforcements, especially if you're going to a MUCH larger size.

a front strut brace will do nothing for you in a 914, with or without an antiroll bar. those are 911 parts. they work on 911 but their front trunk structure is lots different. just because they will fit a 914 doesn't mean they're useful.

[ken914]

Why has no one done this yet??? (IMG:http://www.914world.com/bbs2/html/emoticons/thisthreadisworthlesswithoutpics.gif)

(IMG:http://www.914world.com/bbs2/html/emoticons/thisthreadisworthlesswithoutpics.gif)

[ArtechnikA]

QUOTE (ken914 @ Mar 24 2005, 09:13 AM)

Why has no one done this yet??? (IMG:http://www.914world.com/bbs2/html/emoticons/thisthreadisworthlesswithoutpics.gif)

critics...

[Dave_Darling]

Oh, I like that "oversteer" pic!! (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Dion, one key point is that suspension setup is all about balance. You have stiffened up the rear suspension of the car very significantly (almost three times as stiff as stock!), and left the front alone. This means that the rear end is very likely to be the one that breaks traction first. (See Rich's picture of the results of "oversteer".) You ought to stiffen up the front suspension somehow to get the car back into balance again.

You can do this by upgrading the torsion bars to larger, stiffer parts. (If my math is correct 23mm might be a decent match?) You can also do this by installing a front sway bar, or increasing the size of the one that is in there. Increasing the size of the front torsion bars is, effectively, increasing the front spring rate, which will make the car's ride significantly harder. Increasing the front sway bar size will not affect the ride quality as much, but both wheels will react when one wheel goes over a bump.

Or you can increase both the torsion bar size and the sway bar size.

The biggest benefit from using a sway bar to do at least some of this "making the front suspension stiffer" work is, as Brad said, because it is pretty easy to adjust the effective stiffness of a sway bar. Not so easy for a spring or a torsion bar...

I, personally, would think about downgrading the rear springs quite a bit. The 100 lb/in rate seems to be a good match for the factory front sway bar (no adjustment though) or the 19mm aftermarket adjustable bar. For 140-ish lb/in rear springs, the 19mm is a bit on the small size but is still useable; the 21mm is a bit on the large size but is very useable and might be the better idea. I wouldn't go much stiffer than 150 lb/in rear springs on a street car...

--DD

[ArtechnikA]

QUOTE (Dave_Darling @ Mar 24 2005, 10:42 AM)

Oh, I like that "oversteer" pic!! (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) The biggest benefit from using a sway bar to do at least some of this "making the front suspension stiffer" work is, as Brad said, because it is pretty easy to adjust the effective stiffness of a sway bar.

it occurs to me that i should have the outside, rather than the inside, line being more curved. but the points are 1) the car wants to swap ends, and with a 914's low polar moment of inertia, it'll probably do it a few times and 2) once the car has lost traction, it continues to go straight, and the essential difference between too much understeer and too much oversteer is whether you're looking where you're going, or where you've come from...

the OTHER benefit to (relatively) bigger antiroll bars, as opposed to springs (as Brad was trying to hint) is that over "just bumps" an antiroll bar pretty much stays out of your way and does not contribute much to overall stiffness. you'll feel stiff springs 100% of the time.

there are other issues, like longitudinal weight transffer - but this response is no place for a book on handling nor suspension design ;-)

[ken914]

The description I always liked was;

Understeer = you get to watch the wreck

Oversteer = they tell you about the wreck at the hospital

[Aaron Cox]

hey!

thats engineering "murry pad"!
LOL - i got me lots of that.......


back to reg. sched. programming (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[Eric_Shea]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) Me agrees with Bradhole and others... I like stock or near stock t-bars (I'm using stock 911 units) and larger sway bars.

However, to address the question of "Stronger" suspension:

If'n I had 17x7 and 8 meat on my ride (same day the monkey's fly out of my butt), I would consider a lot of the fairly easy tricks to beef up the spindle and steering arm. If you have access to a welder (either the machine or the guy next door) you can "strengthen" your suspension to handle the extra G's those tires can deliver. Check the threads for RS and RSR upgrades and/or raised spindles. I'm not saying you need to raise your spindles, it's just that there's a picture of some steering arm and spindle reinforcements in one of those threads. (if my feable old mind serves me correctly). (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif)

[TravisNeff]

There is the talk of balance, but you also have to remember he is running 1" wider in the rear so he will have more stiction in the back with that to offset a little bit of the beefier springs in the rear. I would start with a swaybar first, use that and adjust till you like it - if you need more then step up to larger torsion bars, or softer rear springs.

I went backwards on mine, I had larger rear springs when I replaced the shocks (150lb) and stock front suspension and no swaybar. Worked fine on the street, I was never pushing the car hard anyhow. I then needed to replace the front bushings and I figured I would need an alignment when done, so now is the time to do torsion bars - in went 22mm torsion bars (and it was cheaper than a bar, cost was a factor at the time). last thing for me was a swaybar. If I was to do it all over, front bar after the rear springs is what I would have done.