Understeer?, Woah... tha's wierd... Options

[Brando]

So, I've been driving the 914 alot more lately (side story to that). And I've noticed since my last alignment that the car seems to have a bit of understeer*

* To clarify, am I correct in saying under-steer is when you turn the steering wheel and the car does not immediately turn (plows a bit)?

So, here's what I got:

Boges all around.
23mm Adjustable bar up front.
Stock rear bar.
Stock tortion bars up front.
120lb springs in back.
Rear ride hieght is 5½" from ground to rockers.
Front ride height is 4½" from ground to rockers.

I do not have money to throw at a solution. I very much would like to keep the rear bar as it does keep the car very stable in wide wide WIDE turns that I like to take very fast. I guess I'm asking, how should I adjust this? Stiffen the front bar? Run it "softer"? Level the car out front and rear? I do not have adjustable perches in the back (consider it stock hardware). New shocks are not an option. When I was running with the front bar alone, I noticed the front of car would stay flat in very tight turns but would plow a little bit -- give it enough gas and it would straighten the ass-end out in the direction I want, when I added the rear bar it made the whole car stay level in turns, but the understeer* remained, was a bit more noticeable. Any suggestions, please fire away.

Thanks. I know I'm crazy, but I can't spare any pennies on my cars for some time. (IMG:http://www.914world.com/bbs2/html/emoticons/screwy.gif)

[SirAndy]

if you can, back off the front bar a bit, make it "softer" ... that means moving the adjuster towards the front of the car ...

also, 4 1/2" in the front seems pretty damm low to me, depending where exactly you measured. could be that you're running out of shock travel on hard cornering, which is no gud ...
you got the bump-steer spacers installed?

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

[Andyrew]

Softening up the front bar will give you more turn in.

But If I were you, I would spend the 70 bucks and buy some 140's or 165 progressives.

Thats a big bar you got... you need bigger springs..

And yes, plowing, my friend, is the ghastly word for understeer...

I know plowing all to well.

[alpha434]

Understeer?

I pulled a really hard U-turn tonight and knocked all the air out of my front tires from sidewall flex. It felt like REALLY bad understeer. I was hard turned and all I was doing was going straight forward. Could that be it?

[Brando]

Thank you guys... I apprecieate it. When I get under the car this weekend I'll be sure to make those changes. I'll raise the front up ½", and if that don't work i'll make it level with the rear.

I probably should have mentioned as well... 930 tierods, bump-steer spacers installed as well.

Where can I get progressive springs that fit stock perches? I've been wanting some for a while but... $$$, and those 120lb springs really make for a comfortable ride (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) And I thought stock rear bar and light springs would be better than heavy springs and a stock rear bar... But I'm not experienced enough with it to make that call.

[Joe Ricard]

Have you adjusted the steering nut? you know the one in the drivers seat.

Keeping the car balanced via trail braking and rolling on the gas smoother will keep the front gripping.

Nail the gas and those little rear springs allow al the cars wieght to transfer off the front tires and they slide.

I would agree on raising up the front a 1/2" but that will only keep more wieght off the front.
Softening up the front bar will definately reduce the steady state under steer.

[SirAndy]

QUOTE (Brando @ Mar 30 2006, 02:22 AM)

Where can I get progressive springs that fit stock perches?

i have a set of 180lbs progressives you can have ...

also, keep in mind that there is NO perfect setup for both, the big track (think high speed corners and long sweepers) and Autocross (think tight, 2nd gear corners) ...

if you find a setup that will *feel* ok for both, you're giving up time on both.
guys that are serious about this have different suspension setups for TT and AX. anything else will always be a compromise.

generally, it's better to have the car stable and neutral at high speeds and live with a bit of understeer at tight low speed corners.
if you have really good turn-in at low speeds, your rear end will tend to come lose on high speed sweepers, which might not be a gud idea ...

interesting topic, isn't it?
(IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Andy

[SirAndy]

QUOTE (Joe Ricard @ Mar 30 2006, 03:55 AM)

I would agree on raising up the front a 1/2" but that will only keep more wieght off the front.

yes, that does seem counter-intuitive (sp?) at first, one would think that raising the front would make the understeer even worse (which is true), BUT

if your car is too low in the front and you run out of shock travel on hard cornering, your front spring rate effectively goes up to infinity, making it infinite STIFF, in which case the rear sticks and the front slides ...

make sure you got adequate shock travel in the front before you do any major changes to your suspension.
raise the front 1/2" and see if that makes any difference ...
(IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif) Andy

[r_towle]

I have to agree with SirAndy here..

I have 23mm TB, and a 21mm antisway bar...180lbs springs in the rear.

I found through some tweaking that you need to raise up the front of the car so when you measure from the top of the wheel rim to the bottom of the fender lip, on a stock car, the front is 1/4 inch higher than the rear.

I also found that with the super stiff setup, your car needs to be a bit higher overall than other cars..I measured a few at the autox, and put mine that low..it was understeer hell.

Raise the car up, go higher than you think, loosen up the front bar.
Get the car so it has oversteer, then use the front bar adjustments to make it neutral.

And the best advise I can give you is this...get it where you like it as fast as you can...then LEAVE IT alone. learn to drive your car without changing any of the settings...it is the most important part...

Rich

[turboman808]

I don't understand where people get this idea to run a thick ass sway bar with soft springs. Just never works well. Those dam honda guys do the same thing all the time and end up ripping the sub frame out of the car. OK I'll stop ranting HAHA

[Joe Ricard]

Don't know if this was posted here before but....
http://rogerkrausracing.com/overundr.html

[Aaron Cox]

brandholio!

take sir andy up on his offer!!!! 180 springzors!

my car went from perfect to "farm plow"

22mm torsion bars and a big ol tarett sway dont get along, so the sway is going to full soft.....

AA

[byndbad914]

QUOTE (turboman808 @ Mar 30 2006, 10:35 AM)

I don't understand where people get this idea to run a thick ass sway bar with soft springs.  Just never works well.  Those dam honda guys do the same thing all the time and end up ripping the sub frame out of the car.  OK I'll stop ranting HAHA

NASCAR most likely. The reason they do it has really not much to do with handling though, but aero. This is my understanding - call it hearsay - from my guys that run regional NASCAR series...

All NASCAR series will have a minimum ground height requirement. This I know for a fact as I watch the techs go around our SuperLates every time we are out. No part of the car can be below that height.

Short track stuff we do you don't even mess with that light spring big bar stuff as you never get enough speed to take the aero into account. However, cup cars at their speeds will want to "hunker down" with light springs, meaning the front chin area especially will move closer to the ground as the speed is increase (the downforce increases). If you can close off the air from going under the car... well you know the rest I suspect.

So they use big bars to be able to make the corners, but soft springs to get the car down below regulation height at high speeds to go even higher speeds on the straights.

My understanding of where that came from, don't quote me on that too much though.

As for ricers, ever goddamn thing they do is stupid, so why wouldn't they do this. You know a well tuned Honda might get to 130mph if you give 'em mile or two to get there. Then with all the wings mounted at the wrong angles, the huge splitters and such, the front will hunker down, the back will begin to fly, and they can crash and kill themselves. Don't tell them, let Darwin do his job (IMG:http://www.914world.com/bbs2/html/emoticons/cool_shades.gif)

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

[SGB]

It's LOW TIRE PRESSURE

The alignment place "corrected" your tire pressure to 26 psi or sumthin. Pump those tires up to 32 psi, set the rears at 28 or so, and report back.
(IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[Brando]

QUOTE (SGB @ Mar 30 2006, 05:55 PM)

It's LOW TIRE PRESSURE The alignment place "corrected" your tire pressure to 26 psi or sumthin. Pump those tires up to 32 psi, set the rears at 28 or so, and report back. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

I already "corrected" the tire pressure. Got the car and they were at 40psi (!!!!!!) front and 44psi (!!!) rear. Max pressure on the tires says 45psi...

Now it's 28 front, 30 rear. That's the best I've gotten with a "light" car. The tires are super-grippy all the way down to 20psi... Yeah, I spent a day doing "tire pressure" after I got the car back.

[Brando]

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

Hey I want to say thanks to those who contributed some advice my direction...

Raised the ride height in the front -- wow, my shocks work! Also level with the rear 5½" front and back from rockers to the ground. I also softened the front swaybar a bit. The car is now incredibly balanced and ... going over bumps in the road and dips doesn't compress my spine (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

It handles great, once again!

[Aaron Cox]

IDEALLY you need to re-align the front now that you raised it....

[SirAndy]

QUOTE (Brando @ Apr 1 2006, 10:07 PM)

It handles great, once again!

glad i could help!

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