Bilstein sport shocks - what springs?

[RLambert]

Well it's done and looking good.

I've gone with Eibach springs, with a main spring and tender. The tender means that the car has soft suspension initially then they compress and the main spring takes over under harder use.

I did speak to Chris for some advice on spring lengths and rates. Gone for 228lb front and 457lb rear. Chris was fantastic, he spent quite a lot of time on the phone with me and sent me some spring perches which he said to pay for if I end up using them.

Also put on a set of drilled discs I had sitting around and a set new of EBC yellows. Found a split CV boot whilst I was under there so changed that too.

Here it is now, what do you think ?

 

[RLambert]

Here is what it looked like before

 

[RLambert]

And here is the front strut. Tender sping at the bottom...

 

[Steve Brookes]

Looks great Richard! []

 

[ras62]

Richard, the helper spring compresses when the wheels are on the ground, its job is to ensure tension on the main spring at all times so it does not get misaligned..Height & stance looking good btw!

 

[RLambert]

Hi ras62,

'helpers' and a 'tenders' are two different things.

As you have quite rightly said a helper spring is a flimsy affair, typically 20-30lbs and would usually be fully compressed, it just takes up the slack when the wheel is in full droop.

A tender spring is a proper spring, you use them so you can get different spring rates on the same shock. Progressive springs do the same job in a single spring but they are ultimately a compromise... a bit like mixing shampoo and conditioner in the same bottle...

 

[Gazza3501]

Thats a good analogy, this link explains clearly

http://www.e30m3project.com/e30m3performance/tech_articles/susp-tech/springs/index.htm

 

[polar964]

Pleased you got it sorted Richard. The stance looks great.

 

[jack.pe]

Looks good!

 

[bobster]

Hi Richard,

You've obviously done all the homework and you're happy with the result so I think I'll adopt the same set-up. But for now think I'll use my original struts as they are running at nearly the same lower ride height and seem ok. Can I ask a couple of questions please.

Can you tell me why you settled on the spring rates that you did. I'm assuming to keep a degree of comfort but improve the handling?

Are the helper springs specific to the the main spring poundage or specific to the 964 strut?

Did did you get the helper springs from the Eibach supplier?

Many thanks,
Bob.

 

[RLambert]

Hi Bob,

Chris at Center Gravity helped come up with the springs rates, I wanted it firmish for track use but still compliant on the road, hence using the tender springs. I think I've got it about right but I won't know completely until I've done a track day.

The rates (and spring lengths) also took into account the dampers used so I'm not sure if they will suit the standard shocks. The other problem you'll have is the spring perches, the bits the springs sit against, they will be too big for the Eibachs as they are 60mm diameter the std ones are 70mm I think. I had to use some different top perches, you'll need different ones on the bottom too.

Chris at CG may be the best person to speak to, it would be easier to get some regular lowering springs for now as they'll fit straight on.

I bought mine direct from Eibach UK as they have the best stock.

Rich

 

[Steve Brookes]

ORIGINAL: RLambert

Chris at Center Gravity helped come up with the springs rates, I wanted it firmish for track use but still compliant on the road, hence using the tender springs. I think I've got it about right but I won't know completely until I've done a track day.

Richard, there will be a bunch of us doing a track day at Donington on Sunday 4th August. I've got some discount codes for the day. Drop me line: boxsey at btinternet dot com if you want to join us. []

 

[RLambert]

Sounds good Steve.

Line dropped.

 

[bobster]

Hi Richard,

Thanks for the advice. Probably easier to go the H&R Greens route then as most people seem to have good experiences on standard shocks.

I'll check with Chris first though and see what he thinks.

Thanks again,
Bob.

 

[RLambert]

Well I've just done my first track day in the car so I thought I'd post an update about it.

As a recap, the car is on Bilstein shocks with Eibach main and tender springs, I have drilled discs, EBC yellow stuff and Bridgestone S02A tyres, 205s and 255s. After I fitted the suspension it went to Jaz for an alignment and to have he corner weights set. The rest of the car is standard and the engine is as it came out of the factory with 115k miles under its belt.

The circuit was Folembray in Northern France and I covered 730 miles over 3 days. The car is definitely firmer on the road and the new alignment has made it a bit more pointy but it is still easy to use and nowhere near as bad as the GT3 I used to have.

I wasn't sure what to expect from the car on track as when I did a few laps around Snetterton last December on the standard suspension the car was a right handful with far too much suspension movement and weight transfer, it was awful and an accident waiting to happen.

Now on track the car is absolutely superb with good turn and negligible understeer and the rear stayed planted with excellent traction out of the tight bits. I did have a problem with the brakes though, the EBCs were inconsistent, after the first session I when came in there was smoke pouring out of the wheels, the 2nd session they were ok, the 3rd I had a soft pedal, I just wasn't sure what they were going to do which was disconcerting heading downhill at 110 mph into a 90 degree right with not much run off ! By the end of the day they seemed better though.

The only cars quicker on the day were a couple of well modified Lotus Elises. I did some laps in a friend's 2005 Boxster S which had a great engine but was let down by over sensitive steering, woolly brakes and rear wheels which wanted to spin up.

I've come away from the weekend in awe of the car, it's quick (I saw 178mph on the speedo!), comfortable and practical and a fantastic track day tool.

There are a lot more things I can do to it like RS roll bars, an RS flywheel and some light weight bits but I'm wondering if I really need to bother. I'm going to put my name down for the Donington track day on the 4th of August so it will be interesting to compare my car to the other 964s"¦"¦

I'll speak to EBC about the brake issues and see what they have to say.

 

[Steve Brookes]

Great write up Richard. Regarding the EBC yellows, you're only confirming what I've heard from others....they're not all they're cracked up to be.

I don't think you'll have much trouble keeping ahead of us normal trackdayers at Donington. []

 

[mcgc0]

Interesting Richard. I was wondering about the EBC route but now more inclined toward Pagid (Blues or similar). Couple of questions; were you using standard DOT4 brake fluid and how long have you had the drilled discs?

I ask about the discs as I hear that they have a tendency to craze/crack (around the holes) after a couple of years use and need replacing. I fitted drilled discs and EBC Greens to the wife's Focus ST about 2k miles ago and received my MOT warning the other day for these. New (plain) discs are on their way.

You happy staying on the fronts as 205's or would you go for 225's? Might induce more oversteer though I guess...

Marcus

 

[RLambert]

I have just given EBC a call and explained the issues I'd had. They said that what I'd experienced in the first session was a normal part of the bedding in but after that they should be consistent so they were surprised I was having problems. They did say that as they were ok in the last session they may be ok now so who knows without another track day. The chap mentioned they had made some changes to the compound so they want me to dig out the boxes and let them have the batch number. I'll keep you posted.

I did run Pagid RS29 on my race 964 and on the track they were great but as a road pad they need plenty of heat to work properly so I found them quite snatchy.

I tried blacks on the race car but over one meeting at Donington they wore out and destroyed the discs at the same time!

On my road car the drilled discs are Porsche I think, they were off the race car and had done several races over in America so they are a little worn, the fronts also have some cracks but nothing to worry about. They don't seem to be any worse after the weekends activity. I'm also running AP race fluid in it.

The EBCs were very good and I didn't have any trouble slowing the car down when the pedal was firm, it was just that it wasn't always firm so I was having to have a confidence dab on the brakes to make sure I had some before I got to the corner!

As for the tyres, yes will stick with the 205's as front end grip was fine. We run 205 on the race cars with no problems.

 

[mcgc0]

Interesting stuff Richard - thanks. Proves the point to me that you don't need to go mad upgrading brakes and discs then with wider tyres to get the performance you need.

What are you going to do then - keep the Yellow's on for the time being and try again?

Cheers

 

[RLambert]

With bigger brakes and track focused tyres the car would definitely go quicker but you really need to be driving your current set up to the max before you splash the cash. People tend to blame the brakes a lot but often its poor technique where the driver is riding the brakes or slowing down too much in the corners....

I'll see what the EBC guys say but I'm tempted to give them a second chance.