Hi Spencer !

At "Rebel" the PSS10 Bilstein for your car are much more affordable than the KW V3 for the 930!
I want to say good for you! :)

Hi folks,

Before I get on to writing up the suspension project, just a quick update on the cosmetic work; I was so pleased with the refitting of the indicators a few weeks ago that I thought I'd also investigate switching out the "brake ducts" as well. They're not genuine Porsche 964RS items, and I hate anything fake, plus they're not actually doing that much. They certainly aren't feeding air to the calipers. The RHS dust is feeding the end of the oil cooler matrix; bearing in mind that this is a road car, most of the engine temp heat build up is when stationary in traffic queues, in which case the ducts are doing absolutely nothing. If I do need more cooling to the oil cooler, then I already have an output form the Syvecs built into the chassis harness to take control of the cooling fan. I'll simply remove the stock fan control harness and let the ECU take charge. The LHS duct is probably more useful insomuch that it's vaguely pointing in the direction of the AC matrix!

So, out they must come. But to do so, the front bumper needs to come off; unlike proper RS ducts that fix from the front, these don't have a screw. Upon inspection they've merely been bonded in (kind of) with a dollop of Tiger Seal onto the spring clip! [shudder]. Thankfully none of the original mounting holes or tabs on the bumper moulding have been butchered.

A new set of fog lamps ordered and collected, I'm now just waiting for the in-fill pieces that sit either side of the lamps. These and the correct fixings are on order with my OPC, along with a pair of new side repeater indicators (I had 2 slightly different colours; no idea which is correct, so a nice new pair are on the way). I've also ordered a pair of under-bumper trim panels. Mine just don't fit into the bumper that well, perhaps the plastic tabs have been stretched. They've also taken a battering over the years with speed bumps so thought I'd get a new set to complete the front-end makeover.

https://img.photobucket.com/albums/v...F4E0234F81.jpg

https://img.photobucket.com/albums/v...s/IMG_8346.jpg

https://img.photobucket.com/albums/v...s/IMG_8345.jpg

Testing, testing....

https://img.photobucket.com/albums/v...s/IMG_8349.jpg

Hoping to get these by the end of the week, install and get the bumper back on along with a little "smile" correction on the front slats.

Project 2 - Suspension Refreshing
 

So, although I've had some of the parts for a while, they've been sat in my home office until the engine project has been completed, hence no writing up of anything so far.

I have been pondering things though - great distraction on some of the more boring conf calls. As mentioned a few weeks ago, my biggest head scratcher is trying to get the Elephant Racing top mounts to work with the KW V3 dampers/struts. And then I had a "eureka" moment last week. This isn't going to make much sense without photos, suffice to say that I have some old GT3 suspension items kicking around, including a pair of top spring perches with a shallow - almost flat - conical profile, which are going to be re-used on the front struts once I've modified them in the lathe.

One thing I know that needs addressing is that the front struts need some kind of axial bearing plates in the assembly somewhere, to prevent spring wind-up when cornering.

1) ER sell a bearing assembly that's 2.25" diameter, sitting between the top of the spring and the upper spring perch. It doesn't look to be sealed from ingress, simply a needle roller bearing plate, with hardened washers sandwiching it.

https://img.photobucket.com/albums/v...2000.00.38.jpg

2) Rebel Racing make a very nice pair of replacement top perches, with a recess machined into the top face that sits up to underside of the monoball. In this recess sits a similar bearing/washer assembly, but smaller diameter (ID = rod diameter) and also weather sealed with a rubber o-ring. Nice setup and reasonably priced.

https://img.photobucket.com/albums/v...2000.02.13.jpg

https://img.photobucket.com/albums/v...2000.02.33.jpg

3) KW's own monoball top mounts have this axial bearing built into them, easy fit and forget solution, but would mean starting again and not using the ER top mounts (which are really nice)

I decided to give the helpful chaps at KW's UK office a call today, who then suggested that they had a cunning plan; intended primarily for use on 996 GT3's (the coincidence is uncanny - those top perches I'm re-using are from my old 996 GT3) are a new spring height platform that has the bearing integrated into it, and again is sealed. Perfect!

https://img.photobucket.com/albums/v...20adjuster.png

Remove my stock spring platforms and refit with a pair of these. Problem solved. £58.50+VAT each and they're also in stock in Germany.

I'll post more photo's of the challenge I've been mulling over tomorrow when I go back down to my office - it should make more sense then!

KW Suspension vs Elephant Racing Top Mounts
 

Ok, so a few photos to illustrate last nights write-up and introduction.....

Firstly the rear damper.

The unit as it comes from KW, with the top "collar" for a stock installation.

https://img.photobucket.com/albums/v...n/IMG_8365.jpg

https://img.photobucket.com/albums/v...n/IMG_8366.jpg

However, by not using these collars, the OD of the lower half of the top mount sits inside the spring; a little slack perhaps, and I'm not happy about the top of the spring sitting directly against the top mount for two reasons:

1) There's only 3x point contact areas, where the spring sits on the underside of the pressed in studs

2) The steel spring, unless retained a little tighter is likely to move and rotate in operation, and probably scratch the anodising on the mount, looking scruffy and compromising its weather protection. Somehow it just seems not-quite-right.

https://img.photobucket.com/albums/v...n/IMG_8368.jpg

https://img.photobucket.com/albums/v...n/IMG_8367.jpg

So my plan of action with the rear dampers is to make a nylon insulator that will sit between the spring and the mount. It will have 3x reliefs machined into the face that sits against the mount, to clear the stud faces, as well as a 10mm high diameter that will take up the slack and hold the spring concentric to the mount. Simple enough, I just need to order some suitable material.

Now onto the front struts - this one's a little more involved.

https://img.photobucket.com/albums/v...n/IMG_8371.jpg

The top of the rod engages into the front monoball just fine; the diameters are correct (OD of the rod versus the ID of the recess in the mount bearing).

https://img.photobucket.com/albums/v...n/IMG_8373.jpg

https://img.photobucket.com/albums/v...n/IMG_8374.jpg

The thread protrusion, without a spring perch installed, is also fine....

https://img.photobucket.com/albums/v...n/IMG_8375.jpg

However, a few things need to be addressed:

1) There is no built-in axial rotation capability of the monoball bearing; this needs to be incorporated elsewhere in the strut assembly, to prevent the spring from winding up when steering.

2) A spring perch does need installing, to hold the spring central to the damper rod. (Oddly, the advice I received from ER a few months ago was contrary to this, saying it's not vital to do so!)

3) Using the stock perch which comes with the strut of course engages onto the step at the top of the rod....but that then prevents the rod sitting up into the recess of the mount, therefore not allowing the thread to protrude. Any perch has this problem; it seems you either fit a perch OR you have it engage correctly into the top mount; the two are mutually exclusive.

https://img.photobucket.com/albums/v...n/IMG_8376.jpg

https://img.photobucket.com/albums/v...n/IMG_8377.jpg

The plan, therefore, is to open the ID of the perch to allow it to slide down onto the larger diameter of the rod, allowing the rod to engage into the mount, as ER intended. However, by using the stock perch means that I'll lose a lot of height adjustment, it's a very tall conical perch.

So...the GT3 perches I mentioned yesterday. Of course, they're meant to install into a 2.25" spring but the added bonus is that they're quite a flat top, unlike the conical KW perches.

https://img.photobucket.com/albums/v...n/IMG_8378.jpg

They still only slide down as far as the step in the rod, same as KW's, but my plan is to bore the ID out to that of the damper rod. I may go slightly larger than this diameter, then make a plastic sleeve insert to make it a snug fit. This will ensure no metal-to-metal contact, not that I think it would be a problem but again it just seems "right" to me. Perhaps I'm over-thinking it, and aluminium/steel would be fine. It's not going to be travelling up and down but would be rotating with the steering.

To alleviate spring wind up, per yesterdays post, I'll be using KW's own lower spring height adjustment platform that has an integrated bearing system, which will replace the stock platforms...

https://img.photobucket.com/albums/v...n/IMG_8379.jpg

These have now been ordered and are about 3-5 days away.

Bonsoir Spencer,

Your KW kit is great, what is the tare of your rear springs in kg? :)

Bonsoir Monsieur Pat!

The tare? Does that translate to the spring rating? If so, then KW don't actually specify what the ratings are in the specifications but the numbers printed on the springs are:

Rear = 90-250 (I presume this is 250mm length, 90kgs/198lbs)
Front = 30-200 (I presume 200mm and 30kgs/66lbs)

There are also helper springs for all 4 dampers, marked as 10-60-80 (Front) and 20-60-80 for the rears. Both are 80mm long, not sure what the "60" refers to, and I guess 10kg and 20kg respectively?

I should also point out that the guidance from KW (after speaking with their tech support yesterday) is that the helper springs are installed under the main springs for the rear dampers, and above the main spring for the front struts. No idea why it's different front to back. A Google search seems to indicate the favoured position is to mount the heavier main spring at the top to assist unsprung mass; I can see how this *may* make a difference, mathematically, but then I would counter that by arguing the CoG would be higher. Anyway, I'm sticking with KW's guidance.

Thank you Mr Spencer ! :D

It’s strange, I find that the value of the springs is low, it seemed to me that these (the springs) had to contain approximately the mass of the car "per axle", for example at the rear (2x450kg) and for the front (2x350kg). They’re supposed to replace the torsion bars, right? :)

Fair point, but don't forget that's the mass to compress the spring a given amount. After doing a few minutes of Googling, I stumbled on a Q&A transcript that was done with one of the guys at KW in the US. There's a question in there re spring rates, and the answer was quoted back as Newtons per mm compression.

So, if these markings are in Newtons rather than kg, then 90N = 9.18kg-force per mm of compression. Multiplying that up to a 1" compression = 233kg/inch (514lb/inch) for the rear springs, assuming linear compression.

For the front, then 30N = 3.06kgf per mm compression; converting that gives 77.7kg/inch (171lb/inch) compression.

Of course, this also ignores the helper spring rates.

Thank you Spencer !

Even taking into account the conversion N to kg I do not find the values adapted to the weight of the vehicle, They seem too weak. :)

Quick update - the rotating spring platforms arrived from Germany earlier today. Beautifully made, as to be expected from KW, and a very nice - but quite tight - rotational feel to them; they definitely feel very much weather sealed!

https://img.photobucket.com/albums/v...n/IMG_8389.jpg

And installed onto the struts....(stock platform next to it)

https://img.photobucket.com/albums/v...n/IMG_8390.jpg

Next job will be to modify the old GT3 perches, and make some nylon sleeves, plus make some insulator shims for the rear dampers.

Sir Spencer, any misgivings about the colors/colours KW selects for its parts...all that purple? Would they do them in, say, black or gunmetal, or is their coporate scheme all that's available? Kind regards, John

Hey John,

Nah, I can't see KW bowing to the whim of a garagista wanting a colour change - I'm sure it could be done by my local plating shop if push-came-to-shove...I guess it depends on how easy it is to disassemble the monoballs, seals, etc from their housings.

I think for the time being though, I have a solution that keeps my Elephant Racing units as Plan A.....although, still no reply from Chuck or anyone else there. It does compel me to start looking at alternatives for all the other items I need, I have to say. On the other hand, I'll be buying through Chris so that will remove the frustration.

I started following Rob Goughery's very long suspension teardown thread over on Rennlist a few years ago. With my project going through it's engine issues I did lose track of where he got to with the numerous 964 refurbs he was doing, but resumed my reading a couple of weeks ago, as well as getting back in contact with Rob (great guy, very helpful). If only I'd read one more page than I got to, before scratching my head on how to make KW's work with ER top mounts - he went through exactly the same issues a year or two ago (with similar levels of help, reading between the lines)....He solved it in the same way as I'm planning but he's used axial bearings very similar to the Rebel Racing ones, i.e., machined into the top spring perch's.

I have to say, I'm really looking forward to starting this now. Driving the car with Rachel over the weekend after a few weeks of it being safely parked in the garage (we've had atrocious weather here recently), I came to a couple of conclusions yesterday.

1) It still does need some engine calibration refinement. I do think it's over-twitchy on the throttle with the un-filtered setting. Makes it extremely hard to drive smoothly or slowly. It's not a deal breaker, but something I'll come back to next season with Troy - there's always improvements that can be made, just depends on how much money you want to spend on it.

2) The suspension is, despite my positive comments previously, crashy as hell, especially over our country lanes. New dampers will be very welcome, as well as measures to counter bump steer (ER do nice looking steering arms that address this)

Is this car apart or can we drive it on Thursday night?

I'll text you.

:eek:

Yep it's drivable....er...you're in Blighty? Sure, shoot me a text John!!

Evenin' all...

The suspension project is now officially underway!

It's been a busy winter with "other stuff"; new toys arriving in the garage, work is busy as usual, etc etc. But finally I've turned my attention back to it with a good old workshop tidy-up yesterday and a few hours making bits today.

The shopping list of Elephant Racing parts is now with Chris, and fingers crossed this should be winging it's way over to me in the next week or so.

So...why the sudden frantic activity? Well, Dad and I have been working on the first phase of a house project, specifically decorating that requires a 360º scaffold construction around the property. Unfortunately, the easiest way to access the property is through the garage and workshop and of course, the car needs to be somewhere else whilst these guys do their thing and construct it. Because of the construction (I've had it built before, about 14yrs ago, when we decorated it last) I know that it needs to be built in front of the garage door, so of course, the car needs to find a new home for a few weeks until the work is done. Currently, the plan is locked in (thanks to Dads project management work) for early May once the dreadful weather we're having has hopefully gone.

Long story short, I'm on pain-of-death to screw this plan up by not having the car mobile in time. Either that or leave it until the scaffold has come back down again in June (probably), which then means not having the car on the road during the summer. And missing Le Mans. Again.

So, it's now underway although nothing has yet been removed from the car - just prep work this weekend.

The machining work today was to resolve the previously described issue of KW front struts and Elephant top mounts to play nicely with each other. After the week I've just had, getting back on the lathe was exactly the therapy required - great satisfaction and fun modifying the GT3 spring retainers.

First job was to make the plastic sleeves, which came out really nice using a length of Nylatron. These slip over the larger diameter of the damper rod. Next job, open up the ID of the retainer, and machine a counterbore to receive the "top hat" sleeve. Again, chuffed that this was such a nice snug press fit, no need to bond them in place.

https://img.photobucket.com/albums/v...n/IMG_9159.jpg

https://img.photobucket.com/albums/v...n/IMG_9160.jpg

https://img.photobucket.com/albums/v...n/IMG_9162.jpg

https://img.photobucket.com/albums/v...n/IMG_9167.jpg

As you can see, they slip over the damper rod per the plan, and allow the top mount to drop onto the shoulder of the rod, exposing the full length of the thread through the top of the mount.

https://img.photobucket.com/albums/v...n/IMG_9164.jpg

The nut is only done up as far as the nylon insert - there's a good 6-7mm of thread left to tighten against....

https://img.photobucket.com/albums/v...n/IMG_9166.jpg

https://img.photobucket.com/albums/v...n/IMG_9165.jpg

I've maybe lost 10-15mm of spring height adjustment, but even so, I'm sure there'll be plenty, as I'm not dropping it as low as it'll go - UK roads, let's not forget. If it won't even get to the same height it is now, then I'll just get some shorter springs or forego the helper springs.

The next job will be to machine some spring inserts to use on the rear springs/rear top mounts, to hold the springs central but also isolated from the anodised body of the mount. I'll need to order some more Nylatron for this, as it's way bigger than what I have in the workshop.

In other news, the new H&R anti-rollbars arrived on Friday. Nice looking bars, and 2-position adjustable for front and rear. The H&R's are 24mm (Front) and 26mm (Rear) versus the stock 964 Turbo bars of 21mm (Front) and 22mm (Rear). UK roads, in my experience, tend to respond pretty well to soft damping and then let the ARB's do the roll control. Setting the dampers to hard is just a nightmare over here, but the Turbo is a heavy old girl, so needs a bit more control than the stock bars were offering (I think). Having the adjustability front and back will also allow me to set it up for my taste in under/oversteer. This setup also comes with it's own bushes - another thing I don't need to worry about ordering elsewhere.

A new bearing and bush removal kit is supposed to be on it's way, but despite anticipated delivery last Thursday, it appears to have got lost en route. Hoping to have that midweek, which paired with my hydraulic press, will make life a lot easier removing and installing the bushes in each arm, as well as the spring plates.

Glad to hear from you again ...
I was starting to get nervous and wonder how all was going...!!
But as usual, u r fire walled...!!
Carry on... hope the house gets completed on time or early so u can go to Le Mans...

Thanks Tweaks! Yeah, still working away on it, it's just that time is limited - very long hours at work, lots of travelling and then the other family activities. Hoping that this project is done a lot quicker than the engine though - a lot of the chassis work (brakes and general cleaning up) was obviously done a few years ago as part of the rebuild, so that'll save time. I'm really hoping that the suspension refurb can be done within a few weeks, once everything is ordered and with me.

The next ponderingment for me is whether to buy my own plating kit. It's not something I've ever done before, so quite keen to give it a go. From what I've seen on one of the YouTube channels I follow, it can be very successful. If I do buy the kit, it certainly won't be the most economical way to get it done, but I will be able to do it very quickly and not at the mercy of the local and busy plating shop...sometimes a good 2-3 weeks turnaround. More investigation needed.

Hi, good to read you Spencer again! :)

Spenny, good to hear from you. Sorry that I don't have anything illuminating to say other than Hi and keep up the good work.

John