track suspension and reindex

[nicksonmsport]

after some coilovers for my turbo track only car. so im not bothered in the slightest about ride comfort etc, just going fast. what are the best options i know gaz and kw offer kits.

can someone also explain exactly whats involved in reindexing the torsion bars, is this just a term for lowering the car on the torsion bars? or is it something more involved.

many thanks
nick

 

[MarkK]

Emc Motorsport in Birmingham for track GAZ,well priced and they know specs for Turbos,well priced soloution.

 

[nicksonmsport]

ok thanks, will give them a shout. i have done some reading up on reindexing and fully understand the proceedure now. although there is no mention for reindexing when using rear coilovers as well. when fitting the rear coilovers, do you set the spring height so that it just starts to raise the car from the sitting height that the torsion bars have already set, how do you determine how much of the load the coilovers should take? if the coilovers are already a much higher spring rate than the torsion bars, do they take over altogether, or do the torsion bars increase the rate over the top of the coilovers? the reindexing guides are for cars running std rear dampers. does the proceedure change when setting up for use with rear coilovers. my difficulty is understanding how to make the coilovers and torsion bars work in harmony with each other, or am i overthinking this?

i would love to bin the torsion bars altogether to make ride height adjustment much more simple, but there are differing views on wether this is effective or not.

 

[George Elliott]

I think Mark has answered your question Nick, and if I understand correctly that solution will retain the TB's.

I don't track my turbo, and someone will surely suggest it would lap the 'ring 0.001 seconds quicker with coils, but my belief is the TB's carry the sprung load deep in the body shell - torque tube area where it is most rigid, which is better than the coils which mount on the chassis rail higher up and further back.

Now tell me you have a 14 point cage[8|]

george
944t

 

[colin944]

If you have never tackled this job before then take it to some one who knows about suspension on these cars and get them to do it.You can get it down a fair bit just by using the adjuster on the spring plate.But if you put coil overs on and drop the spring plate to far on the torsion bar the your coils and your torsion bars will fight with each other.Personally I would never fit coil overs on the back of a 944 as you are putting alot of pressure on the swing arm which is alloy and not designed to take the loads you are asking of them.If you haven't done this before then it is very easy to make a complete horlicks of it.I have done loads of air cooled VW's and a couple of 944's inc my own.They all work in the same basic way, and my advice would be to mark all the positions with tipex or better still an engraver before you pull it to bits.It's not a ten min job on a 944 as you have to drop the torsion beam in order to remove the spring plates from the torsion bars.You will find while you are at it you will probably have to replace most if not all the rubbers and the mounts on the torsion beam that bolt to the body beside the fuel tank.

 

[944 man]

Id say: take it to EMC and let Alex struggle with the siezed up fasterners and torsion bars and get him to drill the holes in the rear wing bottom. Now you will be able to re-index yourself if you need to, without having to remove the gearbox or anything, withdrawing the bars out through the holes. It takes about thirty minutes when everythings free.


Simon

 

[edh]

My S2 is at Promax today for Geo - running KW's. Andy's initial take was that the car was OK without reindexing as it sat low enough at current ride height.

I'm still trying to get my head around re-indexing + coil springs and how to (and how not to) set them up. Presumably you want both the coil and torsion bar to be loaded at rest, so how do you achieve that when you fit them?

And how can I determine that my car is OK as is? Andy Moss fitted the KWv3 and I know he didn't re-index, just adjusted the spring plates.

 

[944 man]

What are your plans for the Civic Ed?

 

[edh]

sold yesterday... (deposit taken anyway)

 

[edh]

I thought Neil's comments were useful to this thread

ORIGINAL: Neil Haughey

Something which stunned me yesterday was that EMC told me that on my car the rear helper springs were not fully bound and compressing the main spring when the car is sat flat. Honestly didn't notice it but of course it meant that as I was going through corners the inside wheel was only running on the torsion bar and a 4/lb inch flat wound helper. It literally only needed mm's of movement to lift off the main spring but of course looked sort OK as sat flat the main spring was under load. Also helps explain why it seemed like I had way too much rebound as of course its the spring+torsion bar that pushes the damper out. Also of course meant every time I braked heavily the same was happening, back end lifts and with only the torsion bars to pull the damper back out its like running with twice as much rebound. No wonder I kept smoking rears....

....If anyone suggests you can put coilovers on these cars again without reindexing, walk don't run, it's plain right dangerous thinking.

I picked up my car from Promax yesterday. I had asked them to set up the geo & ride height on my KWv3. They decided not to alter the rear ride height at all - and are quite happy with the current setup / ride height on KW's without re-indexing (I know it wasn't reindexed when the KW's were fitted). It certainly drives very nicely on the road.

I guess I will have to get under the car and see how the spring & helper move as the rears leave the ground. I think I can find enough ramps / blocks to give myself room to look under without being squashed.

 

[colin944]

The thing you have to remember about setting up suspension is that mechanically speaking it is a very simple job.However getting the settings right once you have bolted all the bits together is akin to witch craft.I would always say that you should go to someone who knows the black art of suspension settings nand get them to do it.It may cost you afew quid to get it done but it will save you loads of time ,swearing, bad handling,and money in the long run.I don't have any experience of EMC but they have a reputation of doing a very good job also Andy at Promax is a good guy who knows his onions when it comes to setting up our cars.

 

[Jonny944CS]

ORIGINAL: nicksonmsport

if the coilovers are already a much higher spring rate than the torsion bars, do they take over altogether, or do the torsion bars increase the rate over the top of the coilovers?

The two different spring types run in parallel, therfore the total is found by adding the two spring rates together.

However, the springs do not mount directly to the wheel hub, therfore it is more instructive to calculate spring rate at the wheel using the suspension geometry.

Rough equivalent motion ratios for the 944 geometry are:
Front Spring = 0.93
Rear Helper Spring = 0.65 (not sure about the torsion bar - but there are published wheel rates for these)

So taking KW v3 as an example:

Front spring rate = 60N/mm
Front wheel rate = 60 * (0.93^2) = 51.9N/mm

Rear 25.5mm torsion bar wheel rate = 31N/mm
Rear helper spring rate = 50N/mm
Rear wheel rate = 31 + [50 * (0.65^2)] = 52.1N/mm

 

[edh]

Ok - I had a quick look this afternoon

It looks like my rear springs run out of travel & the helpers start to open up after approx 1cm of suspension travel, so sounds similar to yours Neil

I wonder how much I would affect rear ride height by winding up the springs a bit..?

Looks like the answer is a proper re-index though

 

[Big Dave]

Im sure most of you chaps know my views on this wonderfull subject.....[][][][]

Get the thing re-indexed... Its THE only way the car will perform correctly.....[ Thats IF you are using the car for serious track work]....[][][]

 

[edh]

Yes, I feel a visit to Emc coming on...

 

[Neil Haughey]

Reindex definitely, 1cm of lift is nothing, have a look at the image in Mark's avatar and that will be on springs at least double that of the KW kit.

Of course as Dave says all these things only come to the fore when properly pushing the car but I know in your case your'e one of the guys that will do exactly that.

 

[Hilux]

Also of course meant every time I braked heavily the same was happening, back end lifts

Talking about wheel lift.....................

 

[Neil Haughey]

I was following a clio cup car at Silverstone that did that going into Becketts. Crazy little cars.

 

[Jonny944CS]

ORIGINAL: Neil Haughey

Reindex definitely, 1cm of lift is nothing, have a look at the image in Mark's avatar and that will be on springs at least double that of the KW kit.

Out of interest, what spring rates do you guys run with the GAZ setup?

 

[Neil Haughey]

Honestly it varies, anywhere between 500 and 800 lb/inch on the front. There is no right answer IMHO as there are guys out there that have been very successful on soft setups and likewise others on very stiff setups.