Geometry Settings After Possible Upgrade

[924Srr27l]

Roger I chose those spring rates for road use and the odd trackday and sprint; at the time I had no intention of doing what I've done to the car now!! At first I was apprehensive that they would knock my fillings out, but my research on what the yanks are up to suggested otherwise; they were right and I was pleasantly surprised at how good the ride is. Knackered old Koni's don't ride particularly well so most quality new suspension will be an improvement. The point I was making is it's all about the damper and spring rate package- firm(ish) spring rates with the right damper will ride well and be a much better car for it. I can point my car down the bumpiest of tight, twisty B-roads and never does it feel anywhere close to unaccountably harsh (and believe me I have paid good money for some very disappointing suspension kits and coilovers over the years that have ridden like crap even with modest spring rates...). The 944 is quite a heavy car in standard trim so it needs the spring rates to match in my opinion and its surprising what you can get away with! That is providing the dampers are a good match.

My car is being kept road legal, but I will be revising the suspension specifically for racing. I'll only use it occasionally on the road for the odd show or Sunday morning drive, so the next set up will be far more compromised! I was referring to the torsion bars in my post above. My front ARB is a 26mm and I run a 22mm Weltmeister adjustable rear, so everything is covered in that department. I could go bigger on the front, but I like my cars to be set up 'on the nose'. Eventually all the rubber will come out of the suspension and I plan on having the dampers re-valved, or swapping out to something else (although I like the billies a lot!).

I think it would help Rob out if he could possibly ride in some cars with different suspension set ups to see what he thinks feels right.

P.s. Roger I've just found your website, what a build!! Incidentally I've built a very similar front brake kit for mine using forged SL6 calipers...

Yes the 20 piston Braking system is quite Impressive! and then some..

Ok, but your Billy dampers can and could be used with the car's standard coil and torsion springs so they if anything are
far softer (being road valved) than your spring choices which are almost twice the original ?

That rear 22mm ARB is well stiff, and the front not that much ? A lot of racers and Roadies go (MO30) 30mm front bar and 18mm rear...

The 944 in general isn't regarded as a heavy car at all compared to other cars in the same era not to mention current.

A stock 952 (Right hand drive) is similar to my daily drive (Ford Focus 2.0 16v) 1400kg

My 924S 2.7 is 1030kg and is too stiff on 190Lbs fronts, the original car was on 140Lb Springs and weighed 1260kg
So I've increased the spring rate a lot relative to nearly a 20% lighter weight reduction and hence it needs to be trimmed
and the ride height raised a bit.

My front bar is 26.8 and rear 16mm, Rear Torsion bars 27mm Hollow Approx 200lbs rate. The rear is fine, has good compliance
and all 4 shocks are Spax Gas adjustable (Front Inserts & Rear Tele's) and I'm on Skinny 7J Rims and 205/55/16 Tyres (all round)

There's no under or oversteer or wheelspin issues, but it does not absorb dips and bumps well... it will not compress because the springs
are too hard on bump, it feels over sprung at the front and under damped, and even worst when I increase the damping as then it doesn't want to go down or up ! and is then just a washboard jarring ride......

I want a higher ride height Rallycross set up, with good travel and not a ground skimming Circuit race set up...for the UK roads.

R

 

[924Srr27l]

I think it's because you made some sweeping statements about "coilovers" making the ride untenable for road use, and a few of us who have 944's with coilovers & higher spring rates just wanted to debunk that.

The sort of setup that rich has looks great to me.

People often make the mistake by fitting coilovers / poly bushes etc.

These cars are very old now and often the suspension is a long way past it's best.
They were pretty good when new, so fitting new parts will be a massive improvement.

I was having this conversation with Chris from Centre Gravity last week.
He was saying that in many cases coilovers are not required.

This piece (above) was found on the TIPEC forum website (June 2016) written by the chairman (Jason Gibson)

I've never met Chris at CG but have heard he is very good , I've also head and read he often spends a lot of time sorting out a lot of cars that
have been slammed and stiffened to the hilt, which many owners wanted and possibly liked for a while...then some change there mind and want
a more Road useable set up and often find they are asking for chris' advice on how to make it better which is of course to raise it, back off the damping stiffness and fit reduced spring rates etc..

The Buzz word "Coilovers" and the kits made and marketed by many manufactures are sold to the many people like yourself and others
who like a much harsher ride quality at the expense of more lateral stiffness..

Believe or not but there are quite a few that don't like this, and prefer just to replace with new shock absorbers and retain the original
springs or buy new original springs.

It's difficult to know what the split percentage is, But I think it's probably only about 20% of these transaxles that get changed and modified
to this extent because the owners want this look and driving experience and a lowered stance etc...I often wonder if it's also and an AGE related thing too ?

R

 

[Neil Haughey]

Wow. Owned one of these cars since 2001, been online through that period as well and I have never yet seen a single 'stanced' 944.

With all due respect I think you need to get around and meet people, their cars and some of the other specialists around such as EMC, NineX, JMG and stop spouting off on this forum. For starters do a search and read back over previous threads on this subject and you will find many people for example saying that KW v3 rode better than Porsche's own M030 or similar Koni yellow setup.

 

[zcacogp]

I know I'm a little late to this party but it's looking like it's an enjoyable one so I'll join in .... []

Rob, I've changed the suspension on my S2 twice. The most recent time was earlier on this year, when I went from worn-out Koni inserts to Bilstein inserts. Each time the springs were re-used and each time I went for the most aggressive end of the standard geo settings, as listed by Porsche. (The most aggressive settings for the S2 were for the 1989 model year and I suspect it'll be the same for the turbos, although it's a little immaterial). I haven't lowered it at all any my driving is road only - it's a daily driver.

Each time I have ended up with a car with slightly vague steering around the straight ahead position but which really grips and REALLY talks to you. I guess it's what I am now used to and hence personal preference plays a large part in it, but I have a car I am entirely confident in.

As far as the comfort aspect goes, I was amazed when I swapped the (worn-out) old Koni's for some Bilstein B6 units earlier on this year. The Bilsteins are known to be a stiff shock absorber and I kept the original (as in, 196,000 mile old) springs, so I was a little concerned it may not be great. However the difference in comfort was amazing; the car feels more compliant and much more comfortable but somehow more 'plush' in the way that it addresses bumps and re-composes itself after bumps. I noticed the difference simply in getting into the car and noticing the way the body behaved when I started it up. My wife noticed the difference as a passenger before we had got out of our parking space. The improvement is much bigger than I would have thought possible. Perhaps this is just a reflection on how past it the old dampers were but comparing them side-by-side with the outgoing ones I thought I was on course to utterly ruin the ride as they were vastly stiffer.

Not sure if my experience is relevant but if you wanted my advice then I'd stick to geometry and spring rates similar to that which the car had when new. It was designed by Porsche who have always made cars that handle well and they employed whole roomfuls of very clever people when they made the 944. Your requirements are fast road, which is what the car was originally set up for (i.e. not track, or hillclimbing.) And if you are not going to buy Porsche parts then buy things from a manufacturer with a good reputation - and I'd put Bilstein, KW and a couple of others in that category. I was disappointed with how long my Koni shocks lasted but bought them because they were the cheap option when I didn't have much money.


Oli.

 

[edh]

I think it's because you made some sweeping statements about "coilovers" making the ride untenable for road use, and a few of us who have 944's with coilovers & higher spring rates just wanted to debunk that.

The sort of setup that rich has looks great to me.

People often make the mistake by fitting coilovers / poly bushes etc.

These cars are very old now and often the suspension is a long way past it's best.
They were pretty good when new, so fitting new parts will be a massive improvement.

I was having this conversation with Chris from Centre Gravity last week.
He was saying that in many cases coilovers are not required.

This piece (above) was found on the TIPEC forum website (June 2016) written by the chairman (Jason Gibson)

I've never met Chris at CG but have heard he is very good , I've also head and read he often spends a lot of time sorting out a lot of cars that
have been slammed and stiffened to the hilt, which many owners wanted and possibly liked for a while...then some change there mind and want
a more Road useable set up and often find they are asking for chris' advice on how to make it better which is of course to raise it, back off the damping stiffness and fit reduced spring rates etc..

The Buzz word "Coilovers" and the kits made and marketed by many manufactures are sold to the many people like yourself and others
who like a much harsher ride quality at the expense of more lateral stiffness..

Believe or not but there are quite a few that don't like this, and prefer just to replace with new shock absorbers and retain the original
springs or buy new original springs.

It's difficult to know what the split percentage is, But I think it's probably only about 20% of these transaxles that get changed and modified
to this extent because the owners want this look and driving experience and a lowered stance etc...I often wonder if it's also and an AGE related thing too ?

R

No-one is suggesting Rob should get his car "slammed and stiffened to the hilt". "Coilovers" don't have to mean harsher ride. KWv3's are a revelation on a 944. That said, Bilstein inserts look to me the most cost effective option, as I've previously posted, and if Rob wants height adjustment, something like this;

http://www.ground-control-store.com/products/description.php/II=77

There are lots of people on here who have put a lot of thought & development into suspension setups for their particular applications. Some are offering their own experiences on this thread. I doubt age is a factor (not in my case anyway..).

FWIW I suspect some of your own issues might be to do with your Spax dampers rather than spring rates.

If I wanted a harsher ride I'd buy an Audi... []

 

[robwright]

Thanks for all the replies guys. I had no idea it would stir up such a debate. But hey I think debate is great. What it has done has given me some really good info and also a lot of opinion, which I also think is great. More than enough for me to now go away, consider the options and make an informed decision. Thanks again guys I will keep you up to speed. I love this forum!

 

[zcacogp]

Ed, your link doesn't work but if it's Ground Control stuff then it will be lovely ...

 

[924Srr27l]

Wow. Owned one of these cars since 2001, been online through that period as well and I have never yet seen a single 'stanced' 944.

With all due respect I think you need to get around and meet people, their cars and some of the other specialists around such as EMC, NineX, JMG and stop spouting off on this forum. For starters do a search and read back over previous threads on this subject and you will find many people for example saying that KW v3 rode better than Porsche's own M030 or similar Koni yellow setup.

thanks Neil..., this is not Spouting but discussing the subject of a member (Rob) considering upgrading his suspension and I'm attempting to assist him with the potential Pro's and Con's from the posted question.

Of course there will always be several people opinions that declare with some products the ride is fine, but really it cannot be the same by the law of physics, and there are differences between all of the products and people's opinions.

For the real die hard's quoting 500 and 600lbs spring rates really will be rock hard and a nasty experience on the road when the S2 & Turbo started life around 160 - 170Lbs?

Yes new technology has and will allow a middle ground with higher spring rates and special valves (KW v3) with high and low speed compression to compensate for the rough and irregular Road surfaces we have in the UK.

Yes, the Porsche Mo30 (KONI) units are known for being quite hard, replacement Bilstein' (Monotube) inserts are seen as more compliant than (Twin tube) Koni Sports and the KW developed valving as mentioned specifically to deal with lumps on roads is the best for both (handling & Ride) that's why they are £2400 and not £565 like the Spax RSX kit.

INTRAX (Holland) also have developed special valving for an excellent ride quality, and I'm hopefully up for a fully bespoke tailored
set next year for my lightweight road car.

INTRAX ARC (Anti Roll Control)®
They developed a unique way to drastically reduce unwanted roll (lateral and longitudinal). Your car will have the comfort and all the other benefits of driving with "soft” springs like extra grip and traction, until you take a corner or need to brake then ARC® will control ride height with the feel of a sport/race/rally setup. While driving over a curb, through a putt hole or over jumps the suspension will absorb them like driving with soft springs. At the same time ARC® will make sure that your suspension won’t during these conditions. So for the first time you can have the benefits of a soft spring set up without the disadvantages of too much body roll and/or collapsing suspension in putt holes, jumps, curbs.

These are high end and will be approx £3500 a set.

Here's some details on the USA Dealer's website :

http://www.lindseyracing....arts/944SUSINTRAX.html

Roger

 

[zcacogp]

People seem to be getting confused between spring rates and damper rates. They are different things and have different effects upon the car's behaviour and comfort. And - most importantly - they need to be matched to each other to give the best result. Changing one in isolation is not helpful at all. And - more complex still - keep in mind that the chassis dynamics also include tyre compliance, bush stiffness and several other things as well. Change any one factor without compensating elsewhere at your peril, and that's why I am skeptical when people start raving about bigger wheels, stiffer springs and so on; setting a car up is a complex business and beyond the abilities of many.

I find that Chris Longhurst is, as usual, excellent on this subject. It's a long read but try this;

http://www.carbibles.com/suspension_bible.html


Oli.

 

[edh]

Ed, your link doesn't work but if it's Ground Control stuff then it will be lovely ...

Fixed

 

[zcacogp]

No it isn't! You need to remove the full stop from the end of the link.

back at you!

 

[924Srr27l]

[/quote]
[FONT=book antiqua,palatino"]EDH
[FONT=book antiqua,palatino"]FWIW I suspect some of your own issues might be to do with your Spax dampers rather than spring rates.

[/quote]



No, They worked brilliantly on the standard car, ride height and spring rates...

I took a calculated guess when I changed and uprated all the spring rates and they simple are too much,
So I will reduce them and also install and have made a custom set from Intrax, which will be valved specifically for the car and Road application.

R
www.924srr27l.co.uk
205bhp / 205Ft Lbs torque
1010 KG (200 bhp per Ton)

 

[edh]

No it isn't! You need to remove the full stop from the end of the link.

back at you!

I did, but somehow it appeared again, anyway, It is fixed (again)

 

[924Srr27l]

Thanks for all the replies guys. I had no idea it would stir up such a debate. But hey I think debate is great. What it has done has given me some really good info and also a lot of opinion, which I also think is great. More than enough for me to now go away, consider the options and make an informed decision. Thanks again guys I will keep you up to speed. I love this forum!

Hi Rob, I might be across your way in my 924S at some point before the end of the year......If it's the Stamford in Lincs?
My Family live in the Bourne & Deepings area, I'll probably not of changed the current set up so you can experience
from the passenger seat the harsh stiffness....... if you like!

R

 

[robwright]

Stamford Lincs yes. Thanks for the offer that may prove useful. I will let you know.

 

[924Srr27l]

My Bilstein home-built coilovers I find them as compliant as the horrible squishy standard M474 set up. The damping is far more controlled and the car is still a joy to drive on the road

I really rate the B6 dampers if you can deal with the practicalities of fitting them.

I've been looking at the (Bilstein B6) website specs since your post, and I can now understand why they are quite comfortable, as the spec seems to suggest they are good for trailering and towing heavy loads and with standard ride heights & springs etc...:

The BILSTEIN B6 is ideal gas-pressure shock absorber for those who refuse to compromise between performance or comfort.

Better vehicle dynamics in any situation.
- For shock absorbers heavy loads or trailering are a big challenge.
- Built to OE quality standards, the BILSTEIN B6 delivers
- Even without lowering you will get better vehicle dynamics for a comfortable street performance in town and on the highway.

• BILSTEIN gas pressure technology
• Optimum grip and enhanced lane stability in day to day and extreme situations
• Improved safety and performance with OE springs

Bilstein do produce stiffer suspension kits for road cars B14 / B16 & Clubsport but only for more modern machinery and
not any classic Porsche transaxles!

But these B6 units sound very compliant and quite soft, ideal for road use and my lightweight application
so I've ordered some front Inserts to suit my 924S standard struts,

I'm not sure if they just fit inside the legs like the originals?
or if they need the hole drilling in the bottom to secure the piston rod etc...I'll cross that bridge when I fit them up!

I've also ordered some Hyperco 2.5" ID 160Lbs Springs, which will be 15% Less rate than my current ones
It looks like they are worth a punt, and Hopefully the two combined, softer shocks and springs will produce a much better ride!

R