27 replies to this topic

[TheRealVXed]

Hi All.  Having taken my car to Hofmanns for a services and MOT and geo after fitting new toe links, they mentioned some interesting information about shocks and spring rates, so wanted to know if anyone had any experience of these things in practice on a VX.

 

Essentially, they think my VX's damping is set to hard (GGP2, which are going as part of this refresh) and the springs are too sort (475lb front 550lb back currently).  They advised that for 80% track / 20% road I should increase the spring rates and decreased the hardness in the dampers.  Has anyone else made this change?  What spring rates should/could I be looking at?

 

Car is stage II sc

 

Thanks!  VXed

[Nev]

Opening a bag o'wasps with that question....

 

Chris is reknown for advising hard springs, I tried his advised setup of 450f/600r springs on my Nitrons and it was bad news for the type of B-road bashing I do, I now have resumed almost OEM spring rates after trying about 9 different combos of springs.

 

If you do 80% track then stiff springs maybe better, though not allowing your car to roll and pitch as much will affect grip and braking respectively IMO. Remember the geometry of the car deliberately changes as you corner and brake, for example the tyres gain negative camber when the car corners and is allowed to roll over, thus providing you with more grip. If you add strong springs you partly eliminate this...

 

As a very general theory, the stiffer you make your suspension, the more snappy you make the brake away point. I've heard of a local "suspension guru" (it's all he does and has done for many years) near here who even implemented a softer than OEM spring rates on a local VX220.

 

I've found through many many hours of tinkering that I prefer slightly harder (+30%) than OEM rear springs, and OEM front spring poundage. When I had the car setup with far stronger springs (eg 450f/600r), the car felt more go-cart like and was fine on smooth roads, but was like driving a tennis ball down a bumpy b-road with lots of pitching and twitchyness that made it scarey.

 

 

Edited by Nev, 05 September 2017 - 02:54 PM.

[Zoobeef]

I have 600 fronts with 150 helpers and 725 rears with 250 helpers.

 

I have a picture from captain vimes of loads of people's setups but I've no idea how to host it now.

[Foxy]

I have 600 fronts with 150 helpers and 725 rears with 250 helpers.

Ah, that's why you're so slow...

[Captain Vimes]

I have 600 fronts with 150 helpers and 725 rears with 250 helpers.
 
I have a picture from captain vimes of loads of people's setups but I've no idea how to host it now.

I think my photobucket links still work (for now)?

Edited by Captain Vimes, 05 September 2017 - 05:17 PM.

[Aerodynamic]

See my own name there. I still have 425/550 and must say they balance isnt perfect with these front springs.

 But works fine on the roads. 450/550 would is a good road/track setup.

 

When running std ARB I would have gone for 475/550 and now with the 1" ARB in hardest setting 425 works but I will go for 525/625 a littlebit harder and less difference between front and rear.

 

Br, Per

[james_ly]

I spoke to Matt Bentley about this a few months ago. He says:

275/375 pure road

550/675 pure track

350/475 for a mix

 

I went for 450/550 in the end and it's great on track.

[Nev]

I spoke to Matt Bentley about this a few months ago. He says:

275/375 pure road

550/675 pure track

350/475 for a mix

 

That sounds more sensible to me. However, cars with those "Pure Track" spring poundages will probably find their cars aren't rolling enough to "add" neg camber in the corners. So to compensate some cars are set up with excessive static/fixed neg camber. IMO this in turn causes subtle issues with braking, excessive inside tyre wear, less "feel" for the snap-away point when cornering at the limit.

 

Also worth noting a stripped out NA with 1 occupant might be 200 Kg lighter than a VXT with 2 occupants. So springs rates should also reflect this, as that is a big difference...

 

Also don't forget how ARB's transfer (i.e. add) to spring load, lots of people have increased their front ARB's by a couple of hundred pounds and not realised how this is effectively being added to their front springs poundages (eg 450 Lb front springs + 200 Lb ARB transfer = 650 lb front spring loading). For instance I think the EP 1" front ARB has a max setting of +250 Lb, whereas the OEM front ARB is just +50 Lb.

Edited by Nev, 06 September 2017 - 08:59 AM.

[Matthew Bentley Racing Ltd]

Every car is going to be slightly different and typically you are always going to compromise on rates. Some damper valving makes spec'ing springs in this scenario difficult. Some dampers run, imo, too much slow speed bump damping.

 

These dampers can give the driver the feeling the car is over sprung (running bumps harshly etc) but in fact is another issue.

 

IMO if you are deviating away from off the shelf supplied springs on dampers then springs rates need to be spec'd to your dampers, car, tyre and use. 

 

Happy to have a conv about it if you think that would help.

 

Matt

[pete-r]

I think there's way too much adjustability to say a particular spring rate is ideal. I run softer springs than most 300/425 but I'm really happy with the way the car drives on road and track with a couple of clicks on the shocks. I spent an afternoon on track with the mechanics tweaking it and crucially writing it all down for future reference lol. My car does lean in very tight bends (wore a hole in my old arch liner) but I like the way it feels which I think it's more important. Once your in the general area in terms of spring rates then getting a good geometry and setup to suit not just the car but how you like the car to behave is far more beneficial.

[Rosssco]

I use Exige Bilsteins with NA front springs (234 lb / 371lb) and stiff adjustable ARB's = excellent on the road.. Never tried on track (and probably a little too soft for hardened track use).

 

I was forever fiddling with adjustable dampers and never getting it right, so try to avoid if possible.

[Captain Vimes]

I tried: 350/450 350/525 425/525 With standard ARB and 1" ARB. 350/450 had too much roll and meant I was killing the outside of the tyre. More static camber could have helped but I was already maxed out on standard suspension components and wanted to avoid too much static camber for road use. The idea of the 350/525 was to offset the increased effective spring rate of the 1"ARB but in practice it just didn't work at all on track - turn in oversteer and exit understeer. 425/525 with standard ARB felt better but I never got back on track to test.. The key is that it all needs to work together - ARB, spring rates, camber, damping etc. I'd talk to someone else that has used Hoffman settings if possible (Firthy?) for feedback as they take a different approach to others.

[Nev]

I heard a rumour years ago that Chris at Hoffmanns ordered a batch of particularly valved Nitrons at one point. I expect some of these ended up on various VX220s and after selling the cars the new owners are unaware of the compression/rebound rates. Maybe their advice of 450f/600r is to complement these.

 

[Strugs]

I heard a rumour years ago that Chris at Hoffmanns ordered a batch of particularly valved Nitrons at one point. I expect some of these ended up on various VX220s and after selling the cars the new owners are unaware of the compression/rebound rates. Maybe their advice of 450f/600r is to complement these.

 

 

Not a rumour, there were 'Randy-spec' Nitrons. Dunno what that spec was, but it was different..

[smiley]

Hoffmann spec still available, but now on the 46's.

A few of the Dutch run them.

 

[Nev]

Hoffmann spec still available, but now on the 46's.

A few of the Dutch run them.

 

 

Do they know what the difference is?  

[Captain Vimes]

Hoffmann spec still available, but now on the 46's. A few of the Dutch run them.  

  Do they know what the difference is?  

http://hofmanns.co.u.../nitron-dampers

[smiley]

Hoffmann spec still available, but now on the 46's. A few of the Dutch run them.  

  Do they know what the difference is?  

Exmantaa and his mate.Mostly track focus. They tried lots of dampers. The hoffmanns made them the happiest.

[jules_s]

Opening a bag o'wasps with that question....

 

Chris is reknown for advising hard springs, I tried his advised setup of 450f/600r springs on my Nitrons and it was bad news for the type of B-road bashing I do, I now have resumed almost OEM spring rates after trying about 9 different combos of springs.

 

If you do 80% track then stiff springs maybe better, though not allowing your car to roll and pitch as much will affect grip and braking respectively IMO. Remember the geometry of the car deliberately changes as you corner and brake, for example the tyres gain negative camber when the car corners and is allowed to roll over, thus providing you with more grip. If you add strong springs you partly eliminate this...

 

As a very general theory, the stiffer you make your suspension, the more snappy you make the brake away point. I've heard of a local "suspension guru" (it's all he does and has done for many years) near here who even implemented a softer than OEM spring rates on a local VX220.

 

I've found through many many hours of tinkering that I prefer slightly harder (+30%) than OEM rear springs, and OEM front spring poundage. When I had the car setup with far stronger springs (eg 450f/600r), the car felt more go-cart like and was fine on smooth roads, but was like driving a tennis ball down a bumpy b-road with lots of pitching and twitchyness that made it scarey.

 

 

I'm guessing that guru was the chap who set my car up as i've not heard lesser rates from anybody else

 

The lower rates on my car (cant remember exactly but they are in my thread) took on board Nevs comments about roll/grip but it ultimately didn't suit the way I like driving the car. It certainly was far far more compliant in a straight line and over bumpy roads and felt far more settled.The problem came when fast/tight cornering which made it feel like you were 'hanging on' due to the increased roll and slap back when changing direction

 

Bag o' wasps indeed

[The Batman]

My old Hoffman spec vx ones where perfect aswell, can't for the life of me remember the spec tho.