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914World.com _ 914World Garage _ What qualities makes the 914 suspension

Posted by: olav Oct 24 2005, 12:10 PM

I've been noticing a lot of people mentioning that the suspension system in a 914 is no match for modern suspension system. Some even mention that a Neon's suspension is better.

What are the problems with the 914's suspension that make it so uncompetitive with the newer cars?

Is it that the 914's suspension in some peoples cars is so old ie old bushings, shocks, torsion bars that are worn, etc that newer cars just have newer parts which makes them better or is the actual design of the suspension been superceded?

Just curious.

Posted by: SLITS Oct 24 2005, 12:12 PM

It's made from German Rustoleum?

Posted by: thesey914 Oct 24 2005, 12:24 PM

Well I know that torsion bars are linier and coils can be made progressive so more controllable. Not sure that modern suspension is 'better'...maybe the ride quality is better?

Posted by: olav Oct 24 2005, 12:27 PM

I'm asking because some people claim that a stock Neon, for example, would out handle a 914 with trick stuff in a A/X event. So that go me wondering why?

Posted by: 914turboford Oct 24 2005, 12:30 PM

I believe the front strut system is essentially geometrically perfect. That is, in the absence of road imperfections, the tires remain perpindicular to the road in all cornering situations. Also, the torsion bars contibute to a very low unsprung weight which helps on bumpy roads. The rear suspension is another matter. The trailing arms are a compromise probably brought on by the wide mid engine. Double a arms are far better.

Having said that, I'd be happy to take on just about any new car with my teener's modified suspension and 200hp Ford turbo engine.
Brian

Posted by: horizontally-opposed Oct 24 2005, 12:35 PM

The same "top secrect" type of springs as the new LMP2?

Posted by: lapuwali Oct 24 2005, 12:39 PM

QUOTE (olav @ Oct 24 2005, 10:27 AM)
I'm asking because some people claim that a stock Neon, for example, would out handle a 914 with trick stuff in a A/X event. So that go me wondering why?

Not to put too fine a point on it, but this is horseshit. A stock Neon would in no way outhandle a tricked-out 914, unless the 914 was tricked out in completely the wrong way and had completely shot tires on it. I owned a stock '99 Miata until a couple of years ago, and it would only JUST handle with a 914 that wasn't particularly tricked out. That 914s can still hold up under AX conditions against "modern" cars tends to bear this out.

Anyone who claims otherwise needs to provide credible evidence to back it up.

That said, AX is basically about the driver, tires, and weight (more or less in that order). Suspension really only enters into the equation on a bumpy course, and a lot of the difference from one setup to the other is down to driver preference, not absolute performance. The driver is so important, I've actually witnessed a Yugo doing better times that a Corvette on the same course, simply because the Yugo driver could exploit his car to the limit, where the Corvette driver was an effete wanker.

Posted by: Thorshammer Oct 24 2005, 12:40 PM

Ah the suspension, a ten letter curse word.

What makes a 914 a poor design? well it's not exactly a poor design. completely. But it is 30 plus years old and has some limitations. Using the stock components it is very good. Up to a point. The point some of us are speaking is geometry when lowered and things like camber curve and gain toe gain/loss in bump/droop.

Just remember, Suspension is a package, if it lifts the front wheels off of the ground or the rears, you are not getting all the cornering force you paid for in the rubber.OVERSIMPLIFICATION ! As for the commonly driven 914, replace the bushings, and the torsion bars/springs add a front bar and align the thing and it is probably more car than you will ever need.

For racing here are some of the details. Front a arms too short creates camber issues. Rear pick up points in the wrong position, (but this is debatable) I'll let youy know in a couple weeks. Car is somewhat flexible, needs to be stiffer. Standard bushings are not acceptable. only some delrin bushings done a certain way are acceptable, and bearings are only acceptable when the trailing arms are "reamed" to make them fit properly ie... in the same plane "which they aren't from the factory.

My set up:
225 lbs front springs
1 1/4 .110 wall front swaybar
930 Heim rod end coil over front suspension
Spindles moved up 22mm
.7Dgree - camber
4.0-4.3 dgrees of caster
1/64 toe out
Bilsteins

Rear:
275 LBS springs
Suspension pickup points moved up by CFR 3 inches
.7 degrees negative camber
1/8 toe in
Ohlins rear shocks

No rear bar.

This is my EP race set up on bias ply Goodyear slicks. I am fighting a rear grip on turn in issue, and exit on the gas, but that may be me with my foot in it too much.

Hope this helps,

Erik Madsen

Posted by: nebreitling Oct 24 2005, 12:49 PM

QUOTE (olav @ Oct 24 2005, 10:27 AM)
I'm asking because some people claim that a stock Neon, for example, would out handle a 914 with trick stuff in a A/X event.

i don't think the debate was referring to AX so much as track driving. IMHO, a mildly modified 914 would be slightly behind a mildly modified miata on the track, all things being equal. but i'd rather be in the 914.

Posted by: jhadler Oct 24 2005, 01:48 PM

Hmm, equally prepared Peon..er... Neon vs. 914, the Neon would win...

Hmm... I would have to say that is a total load of steaming

As for the innequities of the 914 suspension? Well... It's not that it's archaic per se but the technology is certainly getting long in the tooth...

The 914 has semi trailing rear and front Macpherson strut suspensions. They have their advantages and dissadvantages. The nice thing about them is that they're compact, saving space for things like fuel tanks, trunks, engines etc. The problem is that they are not optimal for a performance car.

The MacPherson strut is a successfull, but flawed, design. For a performance car, you want a suspension that will keep the contact patch of the tire flat on the ground through as many possible situations as possible. The front Macphereson strut suspension is great, but under heavy corner loading, it beomes a liability. As the body of the car rolls, and all cars will exhibit roll to one degree or another, the upper suspension pickup point will move to the outside of the turn. This has the undesirable result of creating a possitive camber effect on the front outside tire, the one doing most of the work. Possitive camber (or less negative camber) can result in less tire actually on the ground, and hence, less grip. But the 914 handles so well!!! Right, there are "patches" to this. A stiff front sway bar will reduce the amount of body roll, and hence, reduce the decambering effect on the suspension. The downside of the stiff sway bar is that you are now coupling the inboard and outboard suspension, and things like surface imperfections (bumps) will tend to negatively effect -both- sides instead of just one. In addition, with a stiff sway bar, you wind up -lifting- the inside wheel as the outside suspension compresses. And hence reducing the overall amount of tire on the ground. The effect of the coupling...

Well, how can this be changed? The SLA (Short Long Arm) suspension design is an exceptional design. All modern race cars will have some form of this suspension design. What is? Lot's of names, but most car makers call it a double wish-bone. The neat thing about it is, if you watch the camber curve vs. suspension travel, is that the camber of the road wheel stays nearly the same throughout the whole range of travel. Unlike the strut which changes as it compresses. In addition, it is FAR less susceptible to decambering effects from body roll.

So, is the 914 front suspension all washed up? Heck no! But it is definitely an older design, and with it comes some neccesary compromises.

As for the Pee-on...er... Neon. It too has a strut suspension, so no joy there. The neon is a capable, and fun, autoxer. But it by no means is a superior design.

Now... The dreaded miata... There's a cheap car, fun to drive, with a -fantastic- suspension design. It's no small wonder that they do so well at autoxes.

Anyway... equally prepared and equally driven?

914 vs. Neon ... 914 by a mile
914 vs. Miata ... That's a close call... with the 1.6? The 914 by a nose. With the 1.8? The Miata with the 70 HP advantage...

-Josh2

Posted by: MattR Oct 24 2005, 02:22 PM

The MacPherson strut's major flaw is it loses, rather than gains, negative camber in bump. Also, only certain combinations of roll center heights and swing arm lengths can fit physically.

The semi-trailing arm suspension in the rear has 2 fundamental flaws also; the camber change is a straight line and the toe change is a curved line (on a position-time plot). Thats the opposite of "optimal".

Now, with this said, the 914 is still a great design considering it was made 30+ years ago without the aid of computers.

Posted by: Tobra Oct 24 2005, 02:45 PM

I would guess that an Integra GSR would crush a neon, stock for stock, and unless the miata is a turbo, it will have trouble keeping up. It has a pretty advanced suspension, upper and lower wishbones anti-sway bars and all that.

This said, I can tell you that there are three places my Honda beats my 914, shifting, braking and acceleration. With the same Yokohama tires, in similar sizes, the Honda will carry 10-15% less speed through the same corner. The 914 is also much more controllable, and pushing hard in a corner, it is extremely easy to control oversteer and understeer. With the integra, it understeers, period, unless you get pretty abrupt with throttle and brake inputs.

The suspension is not bad, just old. It has taken 30 years for other cars to catch up. If macpherson struts were all that bad, why does the "Ultimate Driving Machine" use them still.

Posted by: jhadler Oct 24 2005, 02:53 PM

QUOTE (Tobra @ Oct 24 2005, 12:45 PM)
I would guess that an Integra GSR would crush a neon, stock for stock, and unless the miata is a turbo, it will have trouble keeping up. It has a pretty advanced suspension, upper and lower wishbones anti-sway bars and all that.

This said, I can tell you that there are three places my Honda beats my 914, shifting, braking and acceleration. With the same Yokohama tires, in similar sizes, the Honda will carry 10-15% less speed through the same corner. The 914 is also much more controllable, and pushing hard in a corner, it is extremely easy to control oversteer and understeer. With the integra, it understeers, period, unless you get pretty abrupt with throttle and brake inputs.

The suspension is not bad, just old. It has taken 30 years for other cars to catch up. If macpherson struts were all that bad, why does the "Ultimate Driving Machine" use them still.

On the track, yeah an Integra can probably pull the Miata, but not very easilly. On an autox course, forget it. The miata will kill the integra.

In performance driving, competition etc. on alsphalt, all other things being equal, the problem with FWD cars is that you're asking the front tires to do almost ALL of the work. My favorite saying about FWD cars (and yes I used to autox a VW GTi), is that it really doesn't matter what you do with the rear end, the tires are only there to keep the gas tank from dragging on the ground...

And as for an Integra vs. a Neon? An Integra type R vs. a Neon ACR? That's close, but the Integra gets it. A regular Integra GS-R vs. a Neon? The Neon gets it. Handles better, and is -LIGHTER-. Weight is key, and the Integra is not a super light car.

And lacking the Limited Slip of the Type R, it's pretty hard to put more power down with only 1 wheel...

-Josh2

Posted by: brant Oct 24 2005, 03:37 PM

My opinion to the origianal question...
it has something to do with chassis rigidity and torsional rigidity.

this rigidity allows the suspension to be more effective and maintain its contact.

This is part of the reason that modern cars and modern suspensions can do so well.

The 914 is an older design with a much weaker chassis than the Neon, ford focus, or probably even the open topped mazda.

brant

Posted by: groot Oct 25 2005, 09:03 AM

There's more to suspension design than camber and toe curves.... but having said that... many of the statements made are true regarding the curves. One must also consider the load path of the forces generated by cornering... or roll center. A mac strut is not the worst thing ever and for many applications, it is the best compromise.

All types of suspension involve a compromise of some sort..... all types... even the celebrated double A-arm.

Ummm.... I think the initial question is a waste of time for bragging rights. Bench racing a Neon against a 914....... prove it on the track or auto-x.......

If you really want to know how a 914 stacks up... look at how it's classed by the SCCA in Solo2 regulations. There's a lot of time and energy spent on trying to make sure many different cars can win each class in Solo2 and you have a variety of preperation levels to check out.

Posted by: Joe Ricard Oct 25 2005, 11:48 AM

I don't know bout dat crap. Neon vs Teener.
Stock for stock on race rubber I think the teener will take it
Street prepared now classed differently ???? DSP for the 914 I am pretty sure the 914 will take it
Street mod you better bring a better Neon. Ain't nothing showing up lately that has beat my 914. Including a real Interga Type R powered Civic.

Posted by: jhadler Oct 25 2005, 11:50 AM

Hey Joe,

Gotta look at the heavy hitters that went to Nationals this year. Street Mod and Street Mod 2 are gradually becoming the insane classes that I knew they'd become...

Wanna win? bring yer checkbook...

As for the 914 in DSP? The Bimmers are gonna be -really- hard to beat. They may weigh more, but they've got gobs of power, and they really do handle extreemly well. Tough one...

-Josh2

Posted by: maf914 Oct 25 2005, 11:54 AM

Macpherson struts are popular because they are compact, light, and relatively cheap. They let you squeeze an engine or, in the 914's case, a trunk between the front wheels. A double wishbone set-up would require a structure to support the upper bones that would intrude further into the center of the car.

Are Macpherson struts and Chapman struts (Lotus designer Colin Chapman) the same?

Posted by: J P Stein Oct 25 2005, 12:35 PM

OK, here's a bit of reality.

Here is what a tricked out CSP Miata with a top flight driver can do. Below him on these results is a former 3 time National champ in SS and a guy that finished 2nd OA at a Parade a few years back.
The Miata guy finished 4 OA in CSP at Topeka last year in a borrowed Miata that he said was " tricked out a lot more than mine".

----------------------------------------------------------------------------
1m XCSP 6 Jim Daniels 94 Mazda Miata 42.084
2m XASP 57 Doug Skinner 73 Porsche 911 42.510
3m AM 7 Neal Stanley TLRC 42.987
4m XSS 1 Tom Kotzian 04 Corvette Z06 43.357
5m AS 93 Denis Cornforth 93 Corvette 43.399
6m AS 21 Chuck Spittal 91 Corvette 43.607
7m AS 114 Ryan Otis 05 Subaru STi 43.705
8m XCSP 106 Tami Daniels 94 Mazda Miata 43.822
9m XES 95 Jerry Jenkins 94 Mazda Miata 43.852
10m SM 30 James Paulson 04 Subaru STi 44.220

Any questions?

Posted by: lapuwali Oct 25 2005, 12:46 PM

QUOTE (maf914 @ Oct 25 2005, 09:54 AM)
Macpherson struts are popular because they are compact, light, and relatively cheap. They let you squeeze an engine or, in the 914's case, a trunk between the front wheels. A double wishbone set-up would require a structure to support the upper bones that would intrude further into the center of the car.

Are Macpherson struts and Chapman struts (Lotus designer Colin Chapman) the same?

Yes, they're the same, except McPherson only applies when used on the front, and Chapman when used on the back.

Posted by: mskala Oct 25 2005, 01:47 PM

I've done a couple of ax's with a miata group, and at least
around here, my ASP (and very lightly modified) 914-6 beats
the miatas unless they are very much modified and in SM2
or CP.

Posted by: Joe Ricard Oct 25 2005, 04:57 PM

I see your point JP. Well sort of. Had I been able to buy the engine I nearly had in the bag. Yup Jake's teener motor in my yellow car with My friend Hassan behind the wheel there woulda been some really concerned SM-2 ZO6 vettes at Nationals.
the car is only one part of the equation. Driver is the variable.

But since I'm back to the reality of buildng my own motor I'll just have to be satisfied with whipping the local guys.

Shoot who knows maybe I'll become a better driver myself through Hassan's mentoring.

Posted by: J P Stein Oct 25 2005, 05:36 PM

QUOTE (Joe Ricard @ Oct 25 2005, 02:57 PM)

Shoot who knows maybe I'll become a better driver myself through Hassan's mentoring.

I'm lucky( in a way) in that I get to watch several guys that do well at tha Nationals. Every once in a while, one of them will jump into the pass. seat and try to help change my misbegoten ways. Watching them run is worth the price of admission. I'm picking up some "stuff"....enuff to make me keep coming back for more ego slagging....now if I could just learn to "talk thru" a course.