After Trekkor's AX school at Infineon I need some confirmation/correction of my assessment. The course included lots of tight 140+ degree turns, two slaloms, and a long left hand sweeper. In all of these elements I experienced oversteer. Braking felt fine, although I'm sure some nice Porterfields would decrease the stopping time.

I'm not interested in upgrading springs or T-Bars because this is mostly a street driving car. But from my 'book learning' of suspension setup, I think tightening the rear would help even out the car. I would like to be able to dial in a bit of oversteer and then ease back off. The only way I can see to do this, with what I have in the car and what I'm willing to do, would be to fabricate an adjustable rear sway bar.

I know many people have their cars set up with no rear bar at all, so am I missing something? I feel like a bigger, adjustable rear bar would also let me run my front bar closer to full hard.

Here's my car setup:
Stock 1.7 (going turbo over the winter)
Stock front T-bars.
19mm front sway bar set at half-stiff.
Unknown age front internally adjustable Konis set on full soft.
Rear bilsteins of unknown age.
Rear springs of unknown rate (but comfortable on street so not HUGE, but not stock either).
Stock rear sway bar.
First generation Falken Azenis (205/55/16) on 6" Boxster 'Snowflake' wheels.
Stock calipers and 'cheap' pads.
19mm Master Cylinder
MC Brace


Also, Trekkor drove my car on a couple runs, so hopefully he'll chime in with an alternate perspective.

EDIT: Original topic erroneously said OVERsteer when I really meant UNDERsteer.

Did you try any adjustments to the front swaybar while there? That's the only adjustment you've got besides alignment and tire pressures (which are also significant variables.) You'd probably want to stiffen the front bar and/or bias tire pressure higher towards the front. Or you could try disconnecting the rear swaybar temporarily - pop one or both droplink off and zip-tie it out of the way. Many people are not fans of rear bars at least on stock-ish cars with low power and no limited slip.

Your struts/shocks may also be a factor. If they (or one) is severely worn or broken than all kinds of funky behavior would ensue.

I run a HUGE (31mm ) front sway bar set 2/3 to firm and stock rear bar.
No oversteer at all on my car.


I spun your car on my first run at the end of a slalom going into a left hander~ Snap Oversteer.

After that, I drove around the handling.
I don't want to call it an "issue".

It is just different.
My first drive in a stock 914 in maybe 8 years?

I was refreshing, actually.


KT

+1

What is the old classic saying, i.e., if the rear is loose, then you need to tighten up the front. Do this using whatever you have on board, i.e., combination of sway bar, tire pressures and shocks.

This may be helpful:

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KT

I wonder if your rear springs are stiffer than mine Trekkor.

Go full stiff on the front bar or get rid of the rear bar.

Stock front torsions, 200# rear springs.
So, yes!


KT

Ya you should have popped off one link on the rear and tried it agian.

So these posts totally confuse me. As Randal mentioned, "if the rear is loose, then you need to tighten up the front." But I need the reverse, if the front is loose, then you need to tighten up the rear, don't I? These suggestions would effectively tighten up the front. I thought that would induce more oversteer.

well then you have Understeer or front push and need to do the opposite .Yup

just going by this in the title "Plenty of Oversteer"

Fun car to drive.


KT

Balance sir !! what you do to the front you must do to the back...JMO

What you are describing is understeer, oversteer is when the rear is loose ...

Yeah, yeah. I'm an idiot. Understeer. I knew that too.

Thanks for posting the pic Trekkor! I was just gonna do the same thing, and you beat me to it. The ass end looks like its sitting up higher in the corners...

The ass-end is normal weight transfer.

I like huge sway bar in the front with stock torsion bars. I think you have a good basic set-up now. Adjust with tire pressure for now.

Also if your rear springs aren't stock, they are at a minimum, 140#.

So is it oversteer or understeer?

Is the front loose or the rear loose?

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OK, missed that post, so it's understeer. The front is loose or what some call plowing. If the front is loose tighten up the rear.

Springs, shocks or sway bar, take your pick and/or tighten up what you have. I always go up (spring rate) at least 25 lbs and see how it performs. I'll have to check my spring stash and see what I might have for you. Are you running 8" Eibach

And as a few posters have suggested get a good alighment. Also corner balance the car as you can alter ride height to get it close.

In a car with relatively stock setup, understeer can be the result of a few things.

Overdriving the corner entry. Plow too hard into the turn, and nearly any car will exhibit understeer. As Trek mentioned, he drove around the car's handling. You're on basically a stock suspension with moderate tires. You will likely find the car exhibiting understeer if you're new to competition driving. It is nearly universal for a new driver to push too hard in the slow parts (resulting in understeer), and not hard enough in the fast parts. Pushing hard in the fast parts, you will find the limits of the car and experience oversteer - guaranteed.

Insufficient camber in the turn will reduce your contact patch to nearly nothing. No contact patch, no grip.

Too soft torsion bars in front will possibly bottom out, and result in instant understeer. The roll center of the car transfers to the outboard contact patch, and grip goes bye-bye.

Looking at the pictures, you've got decent body roll, but not excessive. A little alignment work can help a lot. Get as much -caster- as you can. Caster is effectively dynamic camber. The more you turn the wheel, the more negative camber you gain. With the body roll you've got, I would say this is your first engineering culprit (gotta remember that the steering nut is usually responsible for 90% of a car's ill-handling characteristics).

Get a good alignment into the car before sinking money into springs and bars. If you're gonna run street tires, a degree or so negative camber front and rear. A little toe out in front (unless you plan to play at a track, then neutral toe). Neutral to a tiny bit of toe out in the rear.

Good luck, and have fun! Don't make any big changes 'till you've got a good alignment. And make sure that the bushings are all good. Crappy bushings make for wobbly and unpredictable suspension movement, rendering all my previous discussions moot.

-Josh

Understeer is engineered into the car ...like all cars made for America !...they want you to go off the road strait,not sideways or backwards....seat time will be your best investment,,,really learn the car then change it and most of the time if you slow down you will actually go faster! try it.. ....#1 rule have fun...JMO

Spot on. The engineered understeer is more of a CYA for the car manufacturers. Go off the road nose first, it's your fault. Go off the road rear first, it's the cars fault. The absurdities of the American legal system hard at work to pull every Porsche 930 off the road... 'Cause when the boost kicked in, and you didn't know what the ^&*% you were doing, you WERE going off the road rear end first.

-Josh

Good points. I may leave things as is and get some more seat time first. That's what I tell everyone else to do. The $250 that custom rear bar will cost me is a whole season of driving.

I'm sure I was coming in too hot on the hairpins, but the sweeper was definitely letting the front come out first and I feel like that would be a more 'true' reading of how the car is set up.

I wish there were more attendance limited events. I would pay more to have more seat time.

Unless you plan on sinking a whole cr*p load of money into the car, don't even think of getting a rear bar. Rear sway bars induce rear wheel lift, rear wheel lift induces wheel spin, wheel spin induces slow lap times...

A rear bar will couple more of the outboard suspension compression to the inboard wheel, and can actually -pull- the wheel off the ground. Big rear sway bars need limited slip differentials. And torque biasing diffs don't like to loose contact with the ground either...

Until you go big, go with a stiff front bar, and little or no rear bar. Sway bars are a second order effect, springs are going to have far more bang-for-the-buck than sway bars will.

-Josh

Hmmm..........plan in a couple of DE events.....now you're talking 4 hours of seat time in a weekend----works out to about $1/minute plus gas & brake pads, of course....

We'll do at least two more schools at Sears next year.


KT

Truth be told you get more seat time at one of Trekkor's events than 10 normal autoxs.

Also important to find a good instructor. Good instructors will help you to start doing things you should and stop doing things you shouldn't. There is a bunch to learn.

And it doesn't take an instructor long, i.e., run a couple of venues (skid pad / figure 8 / box course) with them and they will have lots of advice on improving your driving.

FYI we used to typically take 10 seconds off a students time in a 50 second autox course at the GGR/LPR one day schools.

You are right about seat time being the priority. Make sure the car is safe, but leave it alone (mechanically) for a year and attend all the events you can. Redwood Region has a great venue and lots of instructors.

Thanks Randal. You're right. Instead of trying to fix a 'problem' with my car, I'll focus on learning skills to make the best of my 'problems'. Those skills are going to be more valuable than the 'fast times' a better set up car would give me.


Took me a couple days to digest this and have it click. Yeah, having a rear wheel lift with an open-differential would mean no more power to the ground until that wheel drops.

Thanks for the help everyone. Looking forward to next year.

This sketch is bogus.
Simply put, if the speed remains the same the car ends up in the same place shown in the first instance.....except with oversteer the backend will get there first.
I've spent enough time going backwards to be unequivocal about this.

The cars attitude may make it "feel" like the 2nd scenario but the line doesn't tighten....unless you slow down (slight lift off the throttle). Even then the line will be wider so you need to take that into account.

Oversteer can be used to advantage at AX *IF* you learn to steer with the throttle AND have quick hands. Things happen hella quick and one doesn't have time to think t thru. It must become an automatic reaction of feet & hands.....easy to say but if it was easy..........

So if we expand on my thought that you should adjust with tire pressure for now, (because I want you to get more seat time before modifying the suspension) and flesh out someone's comment about if the front is loose, stiffen the rear - then you can stiffen the rear in three ways: one, bigger sway bar. I have never heard of anyone putting a bigger sway bar on a 914, the leave the stock one or take it off completely. I have a torque biasing differential so I leave mine on. Two, stiffer springs. We don't know what you have so I suspect they are 140# which was one of the more common aftermarket springs. (easy enough to do of course and probably only $100 even if you go new) Three, add air to the rear tires, or, take air from the front tires. Whoa! Hey! That's cheap.

By the way, if you want, I can send you my suspension settings. You know how twitchy and anxious to turn my car is.

JP may be an irrelevant old fart but this is exactly how I like my car set up. My 240Z handles exactly like this. If you come into a corner at anything above 8/10ths, you're busier than a one-armed paper hanger. Fun though not really the fastest. Some cars are better suited to it than others. I have always found the 914 to be too balanced by nature to get a whole lot of squirrelly.

If you go ahead with your plans to turbocharge that 1.7, you had better develop the skill called throttle steering and hope the turbo doesn't kick in right then...

FWIW the Weltmeister rear bar is slightly bigger (1mm as I recall) than stock but more importantly it has adjustable drop-links and harder bushings. Unfortunately, its geometry and build quality are crap. I went back to stock on my car...

Big torsion bars, big front sway bar, big rear springs, no rear bar...

Greg Fordhal has a great saying. Keep making the front stiffer 'till it won't turn, then stiffen up the rear to make it neutral.

I ran: 21 mm torsion bars, 21 mm front sway bar, 200# coils.

Very crisp and responsive, and yet I could still drive it on the street without loosing a filling...

-Josh

BTW, Throttle steering is not limited to hi-HP cars. Remember the traction circle. As you approach the tire's limits, all inputs lessen the tires traction ( the first trick is to get there & stay there)......smooth is fast, eh? Exceed the traction at your peril and know what to do when that happens. A push is safe but not as fast as the car is capable of IF properly set up/driven. Easy to say but there is only one way to learn.

My personal revelation was (some years back) at a single cone 180 turn. You could grind the front tires to dust while time passed......that sucked. Better to rotate an oversteering car and get the effin' turn over with. Sure, at some point the car was going slower than out there in marble land but over the section it was much quicker.
I grew to love them 180s.

BTW, Pre LSD with 21mm T bars, I ran 275lb springs in back (with no rear bar) to keep the inside rear tire planted. On the road it wasn't that bad as I had good revalved shocks.....I did get double vision a couple times on our gawd awful AX venue.

I tried to induce oversteer to get around the 180, but I don't know what I'm doing and either my car isn't capable of that, or I was doing something wrong. I just added to the oversteer.

Lets say the 180 is to your left, brake hard in a straight line approaching the pivot cone. Make sure when you get to the pivot cone your speed is fairly low.
While still under braking, jerk the steering wheel hard to the left and release the brake.
This will get your ass end to come swinging around.
Counter steer while applying throttle to prevent a 360.

If done correctly, you just did a "power" slide around the pivot cone without having any power to speak of.


PS: This takes some practice to get right, but when it does work, it feels like magick ...

PPS: The key is not to be too fast when you get to the pivot cone. If you are too fast when you (jerk) steer into the corner, your front end will not "stick" and pivot and you will plow (understeer) and the car won't turn.

Interesting...

Uh oh, McMark is on the path of AX addiction. Very common with 914 owners!

Keep going, driving, learning, sliding before making radical changes to the set-up.

At AX, even in the mid-engine 914, trail braking is a great tool. Trail braking is essentially forcing too much forward weight at the initiation of a turn, causing the back end to "get light", which when used properly will induce oversteer needed to squirrel around tight corners at speed. I'm sure there will be a better definition soon!

Adjustable spring perches in the rear are awesome, opening up the entire range of 2.5" diameter springs. I have 175lb rear springs w the Welty 19mm bar up front full soft. You can stiffen the rear, or soften the front, to address understeer. I hate understeer!

Oh so satisfying that most AX courses feature a left turn followed by a right turn etc, so a little snap oversteer results in that fun "dancing between the cones." I've been told this can be the fastest way through some slaloms, but warned that it is risky and back-fires often (so proud I haven't done a full 180 spin in over 8 races!).

Looks like conditions weren't too wet last weekend! Awesome. Bummed I backed out due to the rain

I spun out this one time...


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KT

Yeah you can say that again. This was my car 3 years ago.

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Now, another 10k later.


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Slippery slope indeed.

Another trick to get your car to rotate faster on a 90 degree corner, that you are approaching in third, is to do a "less rev" down shift and let the clutch out quickly. The engine will almost lock up the rears and the car will rotate faster than what you could do with a correct line. Kind of like using a handbrake, but boy does the car rotate quickly. Do not use this trick on a hill climb.

I feel somewhat responsible. He got addicted in my car which is prepared to the max...

To The Max ? your Sooo 80's

Pucker up and smooch Jeff!

The paddock is a bad influence.

Yeah, but I was understeering your car too Rob!

That's your driving...

Wait, now when you say understeering, do you really mean...

under driving , is what i think he meant..to the max.



many years ago one could practice the 180's in the high school parking lot late at night,
well untill you got caught, by the police or your Dad wondering what all the rubber was from on the back fenders.

I discovered Mark's tires are...ahem... a little old.
When he gets some fresh rubber on the car it will be a whole new deal.

I think it will be pretty good, actually.


KT

A little? How old is a little?

KT