Ride Heights, your wisdom please

[fewtrees]

Hello Oracles,

I had KW V3 installed recently and they've settled in (a lot). A consequence is the ride height is reduced and scrapes the road a few times. More than I'd like and not enough clearance for spirited progress.

Below are photos of each corner and a profile view so yet an idea of where it's at. 

Summary:

Ground Clearance: ~140cm

Front Floor to Rim: ~655mm

Rear Floor to Rim: ~687mm

The question is, if you've got a lowered car, what height are you running that fits your compromise between ground clearance and handling?

Front - Side View

Front Right Ground Clearance -

Front Left Ground Clearance

 

Front Right/Offside Ride Height -

Front Left/Nearside Ride Height -

 

 

Rear Side View

Rear Right/Offside Ride Height -

Rear Left/Nearside Ride Height -

 

Sorry it's mucky, this was after Chatsworth House and driving through a field..
 

Edited December 4, 2022 by fewtrees
Added measurements

[fewtrees]

Sorry typo.. ground clearance 140mm not cm!

[Nobbie]

Presuming that are these

https://www.design911.co.uk/fu/prod13619/KW-Variant-3-Adjustable-kits-Porsche-987-Boxster-11-2004------987C-Cayman-01-2006--/

The blurb says 30-60mm drop😳 which strikes me as aimed at track use, even if they are set at their smallest drop I think you will struggle. My 986 is MO30 which is 10mm drop and I wouldn’t want it any lower given the roads I drive. I’m not sure if any factory mods from Porsche for road use are more than 20mm. Seem to remember a guy came out with us once on -30mm springs and left halfway through😬. Do you do much track work?

[fewtrees]

@Nobbie I will be doing track work in time. I did a whole bunch of research before shelling out for these, so I guess I need to max out the height and see how that goes.

If you’ve got any measurements I’d love to know how much difference there is. 

[map]

5 hours ago, fewtrees said:

A consequence is the ride height is reduced and scrapes the road a few times.

Which parts of the underside are scraping?

Some bits are wear items (underbody aero for example) and other parts less so - sump as a for instance.

I ran my 986 at -30 for a number of years and just replaced the underbody plastics as required. No worries.

What prior experience did the folk installing these coilovers have?

To get the best from comparative ride heights we should know the distance from top of the wheel centre to the wheel arch. This data isn't affected by tyre choice/ pressures, wheel design or size - it is also less susceptible to variances caused by the car being measured on an uneven surface.

[Macus]

I’ve always lowered my cars on coil overs, mainly for aesthetics: ( Mk2 golf’s, Lupo GTi, Corrado VR6) but I just couldn’t imagine the boxster being lower… whenever I’d raise a car back up it always felt loads faster and it was so much less wincing going over bumps. 

[Andy Mac]

Hi @fewtrees When I put coil overs on the 996 I spent ages fannying about trying to get the heights right (local alignment place let me use their ramps to get a level surface in the end as I was going round in circles using the garage floor etc).

I based the heights on the Porsche specs / data. Which gives where to measure from and a +\- spec heights (from the designated points underneath). Then once I was happy (ish !) I had the alignment done.

Is there similar charts out there for the 987.2 for a decent starting point? 

 

[fewtrees]

2 hours ago, map said:

Which parts of the underside are scraping?

Some bits are wear items (underbody aero for example) and other parts less so - sump as a for instance.

Sounds like plastic to me, not metal. I expect it's the little flaps in front of each wheel that hit the deck first but a couple of times its a jarring thump.

2 hours ago, map said:

What prior experience did the folk installing these coilovers have?

Loads, the garage are a suspension specialist and have done the work for many race cars so I believe they know how to install coilovers plus set them up. If anything I expect they've set them low so after settling I'd no doubt have to go back.

 

2 hours ago, map said:

To get the best from comparative ride heights we should know the distance from top of the wheel centre to the wheel arch. This data isn't affected by tyre choice/ pressures, wheel design or size

Just been out and measured the front ~330mm. The recommended minimum is 325mm so not far off.. I'm using this as a good indicator I can lift the car by 10-15mm. 

@Andy Mac - I'm scouring the net for a similar table, hopefully I can find something..

4 hours ago, Nobbie said:

My 986 is MO30 which is 10mm drop and I wouldn’t want it any lower given the roads I drive

Totally get that, following you last run out is when it first started hitting the deck 🙂

Edited December 4, 2022 by fewtrees

[entdgc]

3 hours ago, fewtrees said:

I expect it's the little flaps in front of each wheel that hit the deck first...

Virtually every time I go out for a spirited drive (mostly B roads) my standard 987.1 scrapes the ground. I was getting annoyed/worried about this so had a closer inspection and I came to the same conclusion as you about the aero flaps in front of the wheels. I would not want mine any lower.

[map]

11 hours ago, fewtrees said:

a couple of times its a jarring thump.

Is this be the suspension hitting the bump stops?  Or does it feel like the chassis is hitting the road?  What impact witnessing is there underneath the car?

11 hours ago, fewtrees said:

Just been out and measured the front ~330mm. The recommended minimum is 325mm so not far off..

Is the "recommended minimum" from the wheel's centre?  Or from the top of the wheel centre as I suggested? My suggestion is based on that being an easy dimension to measure for forum comparisons.  If the "recommended minimum" is from the wheel centre then you've probably already settled at the lower limit.

11 hours ago, fewtrees said:

I'm using this as a good indicator I can lift the car by 10-15mm

By all means lift the car but make sure you retain whatever chassis rake currently exists.  Rake (as you probably know) plays an important part in chassis balance, turn in and braking performance/response.

[fewtrees]

4 hours ago, map said:

Could this be the suspension hitting the bump stops?  Or does it feel like the chassis is hitting the road?  What impact witnessing is there underneath the car?

I need to check that, there's been enough contact so wherever it happens it should be fairly clean and obvious..

 

4 hours ago, map said:

Is the "recommended minimum" from the wheel's centre?  Or from the top of the wheel centre as I suggested? My suggestion is based on that being an easy dimension to measure for forum comparisons.  If the "recommended minimum" is from the wheel centre then you've probably already settled at the lower limit.

The recommendation is from the centre of the wheel and my measurement was done in the same way. Makes sense as it ignores wheel size/tyre wall height etc..

4 hours ago, map said:

By all means lift the car but make sure you retain whatever chassis rake currently exists.  Rake (as you probably know) plays an important part in chassis balance, turn in and braking performance/response.

Yup, totally agree.. Originally the nose pointed to the moon and understeered massively on exit.

[temporarychicken]

I had lowering springs on a Boxster, -30mm allegedly. This was 10/10 for aesthetics and filling the wheel arches, but it was not a handling improvement, and also a bit too low for road use. I later got rid of that and fitted a factory X75 kit which I believe was -20mm. The latter was vastly better of course, and superb on track. However, whilst braking on rough roads it kind of went to pieces. You can't have it all, no matter what you put on.

I've not had coilovers on a Boxster as such, but on a BMW M2 I used the official BMW factory kit (also based on KW V3) and the same advice applied as above, i.e. set the ride height according to their specs.

The recommended height settings can be deviated from if you need to. They are, of  course, adjustable!

What I've discovered over a long period of time is that any more than -20 doesn't really give you much. I guess that's why Porsche themselves only go this far with their available parts. These cars have a very low centre of gravity in any case.

Another thing regarding the KW V3... It's well worth dialling down the bump and rebound quite a bit for road use (assuming you're not mega lowered) and then tweaking to track settings once you're there. They are quite comfortable and nice to drive on the road with softer shock settings. This is easy enough on the M2 since you've got thumbweels under the rear wheelarch for both bump and rebound. On the Boxster you've got rear struts so you'd need to tweak rebound via the top mount, same as the front.

All that said, looking at the original pictures it looks just about perfect to me. If it's scraping then maybe a wee bit up at the front. A few mm makes all the difference, as the seahorse said to the chiropodist.

[MickH]

Just for balance. I have H&R 35mm lowering springs on Koni Sports and adjustable rear toe arms
car handles amazing. Never bottoms out unless its extreme roads. And even at that its not a major issue. 
car is deffo quicker than standard. And my pec instructor said it was the best 987 he had sat in for handling. 
 

[fewtrees]

After doing some digging I found a few setups and heights..

The height is the wheel centre to the arch (as shown above). The % attitude is the %age of the front to rear incline so you can see most setups tip the car forward.

 

[Nick C]

I haven't read all comments but I fitted the H&R M030 springs to my 987s, my car doesn't have PASM and the stance now looks great, bit of a compromise because I like a slightly lower stance but the roads are terrible so too low isn't practical, I don't like the slammed look either so these for me were perfect. 

[Dubdubz]

On 12/5/2022 at 5:30 PM, MickH said:

Just for balance. I have H&R 35mm lowering springs on Koni Sports and adjustable rear toe arms
car handles amazing. Never bottoms out unless its extreme roads. And even at that its not a major issue. 
car is deffo quicker than standard. And my pec instructor said it was the best 987 he had sat in for handling. 
 

@MickH did you have to have anything adjustable on the front side too or was it just the rear toe arms, obviously would need setting up geometry wise after installing

of interest what wheel size are you running too?

Shame there isnt a -20mm - the M030 isnt quite enough visually

[Happy Days]

You could have weeded the drive and washed the car before posting those photos...

[MickH]

21 hours ago, Dubdubz said:

@MickH did you have to have anything adjustable on the front side too or was it just the rear toe arms, obviously would need setting up geometry wise after installing

of interest what wheel size are you running too?

Shame there isnt a -20mm - the M030 isnt quite enough visually

After much research the front doesnt need additional adjustment. Thats even with -35mm. It would possibly make a miniscule difference. 

[MickH]

Oh and Im running 18s

[edc]

On 2/3/2023 at 10:21 AM, Dubdubz said:

@MickH did you have to have anything adjustable on the front side too or was it just the rear toe arms, obviously would need setting up geometry wise after installing

of interest what wheel size are you running too?

Shame there isnt a -20mm - the M030 isnt quite enough visually

The issue with the rears is that as you go lower the range of adjustment effectively reduces and there is not enough range to balance off camber and toe. If you optimise the toe you increase the negative camber. You don't have this problem on the front plus you can get more negative camber by widening the top mount slot by 5mm or so. 

[fewtrees]

On 2/3/2023 at 12:51 PM, Happy Days said:

You could have weeded the drive and washed the car before posting those photos...

😁 Too busy out driving the car 😁

[Dubdubz]

On 2/4/2023 at 10:49 AM, edc said:

The issue with the rears is that as you go lower the range of adjustment effectively reduces and there is not enough range to balance off camber and toe. If you optimise the toe you increase the negative camber. You don't have this problem on the front plus you can get more negative camber by widening the top mount slot by 5mm or so. 

Thanks EDC

So if I go -30 what parts do I need to get at the same time to allow the adjustment - I know there is a chance I'll need some standard parts that are worn but what adjustbale doodads will I need please and the best place - found some Rennsprt ones that seem ok money but there is a few options or at least 2 parts I could see!
And possibly shocks - so then a coilover set becomes a decent proposition cash wise 🤔

@MickH My summer wheels are 19's althought the rolling radius should be close to you its the harshness lowered springs might bring, winters are 17's


[sorry for the thread hijack OP 🙂 still on topic though!]

[fewtrees]

33 minutes ago, Dubdubz said:

[sorry for the thread hijack OP 🙂 still on topic though!]

Reminded me to post my adjusted and settled heights.. 🙂

348mm front
366mm rear

There's an occasional catch at the front but overall it handles the bumps very well and balance on exits is rear slip first. It's not as angled forward as it was but seems fine for the road..

As I've fitted coilovers (KW V3), setting the height was very easy 🙂 and there's plenty of range in there. Now to set the alignment again...

Edited February 6, 2023 by fewtrees

[MickH]

19 hours ago, Dubdubz said:

Thanks EDC

So if I go -30 what parts do I need to get at the same time to allow the adjustment - I know there is a chance I'll need some standard parts that are worn but what adjustbale doodads will I need please and the best place - found some Rennsprt ones that seem ok money but there is a few options or at least 2 parts I could see!
And possibly shocks - so then a coilover set becomes a decent proposition cash wise 🤔

@MickH My summer wheels are 19's althought the rolling radius should be close to you its the harshness lowered springs might bring, winters are 17's


[sorry for the thread hijack OP 🙂 still on topic though!]

I messed up and did the springs only originally, this killed the standard shocks which were most likely the originals.  So my advice would be to do it all at the same time to save the hassle and labour cost.  I've always been a fan of coilovers but most people on the internets seemed to suggest the Billies or Koni's were a better option, so I went with the Koni sports and could not be happier.  You will need rear toe arms too, these are the ones I went for, although were considerably cheaper at the time

https://www.ebay.co.uk/itm/183899476445

They state 997 but they are the same as 987 ones :).   I did also try adjustable camber arms from them, but those are different so they went back. Didn't actually need them, just thought I may as well.

 

I wouldn't worry about the 19s, I still have a massive arch gap.  Actually wish I had sourced 19s, although the 18s are super compliant.

 

Mick

[edc]

Fyi, these adjustable rear toe arms are the same generic ones from many other suppliers and are from Alibaba just like the exhaust.