Thread: Koni Raids

BTW I had a set of "normal" Konis on a GQ Patrol while in Thailand.
I found them to be really good for comfort and a good compromise for suspension control as they reduced/eliminated the tendency for the Patrol to"corkscrew" on rough curves, due to the Panhard rods displacing the axles.
However in my research this time I could not find normal Konis listed by any retailers for a RRC, only "Heavy Tracks". Now I recall, it was these that I asked Graeme about, but the Raids would only be stiffer!
So far the Billies seem OK for ride on my currently completely empty RRC, however the roll stiffness of the back is up a lot from the Polyairs. I seem destined to have yet another "on again off again" relationship with Polyairs.
I hope the Billies are OK having just spent about $350 for the rears and $550 for the fronts including revalving.
I just remember the last time I had Billies which was on my 83 520i when the high speed control was great but the low speed ride was terrible.
Regards Philip A

Originally Posted by PhilipA

<snip>
However in my research this time I could not find normal Konis listed by any retailers for a RRC, only "Heavy Tracks". Now I recall, it was these that I asked Graeme about, but the Raids would only be stiffer!
<snip>
Regards Philip A

Heavy Tracks are merely the old Koni Specials re-named for most 4WD's, eg. Land Cruisers and Patrols, although the whole Land Rover line has been re-vamped and are low pressure gas versions now.

The Heavy Tracks we have on the Patrol are great in the rear, but a bit too floaty in the front (not enough rebound) even on maximum adjustment. I keep saying I'll re-valve them, but haven't got around to it.

These might work as well for you Aussies

Koni RAID dampers for:

Discovery (89>94MY/as from series MA 94>98MY)
Defender 90/110/130 (84>04MY)
Range Rover (71>94MY)
Range Rover Classic ecl. air suspension (95>96MY)
fit vehicles with std or rsd* suspension.

Front: 0-50mm 90-5374
Rear: 0-40mm Rear 90-5375
*Rear rsd susp. only: 40-60mm 90-5401

Originally Posted by rick130

Koni's generally have less low speed bump from the factory, and as the bump forces are not controlled via the piston, but in the foot valve, there is less inherent harshness for the same degree of damping, less stiction with the smaller diameter piston and larger section piston rod, although this has obvious downsides in the internal forces that need to be generated to control the same input force....

Doesn't using the foot valve instead of the main piston make for some low amplitude harshness? Related I believe to there being a certain amount of shaft stroke needed to displace enough oil to open the shims enough.

On a landrover with rubber bushes at each shock mount and large tyres I doubt it could ever be felt, but in mountainbikes I think it was one of the main reasons Manitou developed their floating piston TPC+ damper, the normal TPC which works just like a twin tube shock with a foot valve controlling all compression has an distinct lack of compliance around the really small bumps like 10mm and under which TPC+ solved.

Originally Posted by Dougal

Doesn't using the foot valve instead of the main piston make for some low amplitude harshness? Related I believe to there being a certain amount of shaft stroke needed to displace enough oil to open the shims enough.

On a landrover with rubber bushes at each shock mount and large tyres I doubt it could ever be felt, but in mountainbikes I think it was one of the main reasons Manitou developed their floating piston TPC+ damper, the normal TPC which works just like a twin tube shock with a foot valve controlling all compression has an distinct lack of compliance around the really small bumps like 10mm and under which TPC+ solved.

Not when comparing a gas pressurised mono tube to a twin tube.

Part of the reason why twin tubes fell out of favour with the open wheel brigade in the eighties and nineties was the inability to develop sufficient bump forces at low shaft speeds/displacements when motion ratios were high, shaft movement tiny and the underwing stability was paramount for consistent downforce.
This was a combination of the smaller diameter piston inherent in then twin tubes (33mm vs 46mm) which was unable to easily generate the forces needed and the way the bump forces were generated.

In the nineties one prominent V8 engineer worked for a number of years trying to get their Penske's to mimic a twin tube Koni in bump. (He was looking for low speed compliance, wanted the cars to roll into and off the corners)
He kept generating piston after piston design to try and achieve it. When I was talking to him over a cuppa at a mates workshop one day around '95-'96 he'd been through about half a dozen piston designs at that stage.

If you look at a generic force/velocity graph of a Bilstein vs a Koni, the Billie will generate bump at a linear rate right from the beginning of shaft movement, whereas the Koni sort of languishes at small velocities/displacements before starting to generate bump forces, a straight line vs a curve.

JRZ in The Netherlands developed a mono-tube in the nineties that mimicked a Koni twin tube in performance by moving all the bump valving into the can and jamming a 22mm shaft into a 44mm ID tube for maximum fluid displacement. (The blokes that designed it were ex-Koni motorsport engineers. One of them took the old 82 series twin tube and added a gas canister on to it when still working for Koni around '84 for Indy car use, and by all accounts it worked well)
The JRZ worked nicely on sedans and other cars that didn't rely so much on an underwing for downforce, as it gave better mechanical grip, and was more comfortable for the driver.
The gas pressure was used as a spring adjunct so it contributed to rideheight, without increasing spring rate and therefore you didn't need to use as much spring, again helping mechanical grip.

After this, Ohlins introduced the TT44 which was a 44mm twin tube that took all the valving off the piston and placed it in the outer tube, and Sachs followed suit. These dampers now tend dominate open wheel circuit racing.