Introduction
You just purchased a Citroën DSR R3 equipped with BOS dampers. All our team congratulates you for your choice and thanks you for trusting us. Your BOS high performance dampers are developed from our years of experience in official championships, on all type of surface thanks to our successful co-operation with winning teams. Our success and results gained in few years show the full and the exclusive implication of BOS Engineering in the research of performance.
The BOS dampers you just bought are especially developed for your car and your type of race. The choice of our technical solutions, the quality of our materials, the precision and the care brought to the as-sembly operations transform your new BOS dampers in an absolute weapon to win.
You will find in this user guide all the information needed to get the best of your BOS dampers in term of setup or maintenance. This hand book talks about lots of subjects for which a private or professional driver can be confronted to setup his set of damper.
We wish you a good reading and hope this document will guide you in your life of driver...
Note : BOS Engineering never stop to increase the range of product in terms of design and quality. Therefore, while this user guide contains the main information and pictures of products, there may be minor differences between this guide and your BOS dampers.
3 4 6 8 10 15 11 13 Introduction Tuning your dampers Detailed views : Mc Pherson Eyelet / eyelet Technical datas Tightening torques Maintenance and inspection Specific strut maintenance Details of inspection Your dampers 11 12 6 14
Tuning the bump and rebound - basics :
The dampers CR60 are 3 ways adjustable dampers: High and Low speed bump and High speed in rebound.
The settings are always referenced with the following procedure counting the clicks number in the following order:
bump low speed / bump high speed / rebound
The adjustments are always referenced with the adjuster completely closed which give the hardest damping force for each independent valve. Then unscrewing the adjuster clicks by click up to the setting requested is making the damping softer.
Setting up the hydraulic bump stop :
The adjustment of the hydraulic bump stop is not set by clicks but in turns in ½ turn increments. The range of setting is 3 ½ turns maximum.
Unscrewing the adjuster (turning anti clock wise) is softening the bump stop.
Tuning your dampers
Position of the bump adjusters (picture 1)
The High and Low speeds bump adjustments are always positioned on the damper reservoir head.
The High speed Bump is tuned by the external hexagonal nut. The Low speed Bump is tuned by the central screw.
Position of the Rebound adjuster
The rebound adjustment is always positioned at the end of the damper shaft. Eyelet / eyelet layout: screw on the bottom of the damper (picture 2)
Tuning your dampers
IMPORTANT
The Hi speed and low speed compression adjustments are fully independant.
Which means that when you adjust Hi speed, there is no effect on low sepeed, even though the LS screw is rotating.
The adjustments by clicks are always
referenced from the adjuster completely closed.
To come back to the base settings, you need to close completely the adjuster and then unscrew clicks by clicks up to the number defined. From full hard, the selected damping valve will be softer and softer by unscrewing it.
In the table page 7, the adjustments are always indicated as number of clicks.
Minus four ( noted -4 in the table) means unscrewing by 4 clicks the adjuster from the reference setting.
Example : Reference setting -12 Clicks : From the adjuster set completely
closed, unscrew it by 12 clicks.
New setting : -4 = soften
This means -12 (Reference) -4 : For doing this, you need then to unscrew the adjuster by 4 clicks turning anti clockwise from the reference (-12) so target position will be -16 clicks from completely closed.
On the other hand, +4 mean that the adjuster needs to be scrown by 4 clicks to finally reach a target position of -8 clicks.
2
2 3
1
Position of the hydraulic bump stop adjuster
The bump stop adjuster is positioned on the side of the damper head opposite to the rebound adjuster.
Strut assembly: the screw is in the middle of the damper head. See drawings page 7 & 9
Detailed views : Mc Pherson
1. Overall view
2. Upper assembly
Top mount bearing
Air filter spacer Top nut
3. Rebound adjuster
4. Piggy Back view
Hydraulic bumpstop adjuster • Alen screw ø 4mm • 3,5 full turns range ( by 1/2 T step)
• Full screwed position = hardest and starting point to count the clicks
• Alen screw ø 4 mm • 30 2 clicks
• Full screwed position = hardest and starting point to count the clicks
Low Speed bump adjuster • screw
• 20 2 clicks range • Full screwed position = hardest and starting point to count the clicks
Hi Speed bump adjuster • 14 mm nut
• 20 2 clicks range • Full screwed position = hardest and starting point to count the clicks
Eyelet / eyelet
1. Overall view
2. Bump adjuster
Low Speed bump adjuster • screw
• 20 2 clicks range • Full screwed position = hardest and starting point to count the clicks
Hi Speed bump adjuster • 14 mm nut
• 20 2 clicks range • Full screwed position = hardest and starting point to count the clicks
Eyelet / eyelet
3. Rebound adjuster
5. Preloader Hydraulic bumpstop adjuster
• Alen screw ø 4mm • 3,5 full turns range • Full screwed position = hardest and starting point to count the clicks
• Screw • 30 2 clicks
• Full screwed position = hardest and starting point to count the clicks
4. Hydraulic bumpstop adjuster Preloader locking ring
Technical datas
CR60
Type Monotube hydraulic damper
Adjustment 3 ways : compression H & L speed + rebound Configuration Separated reservoir : piggyback type
Rod Chrome steel ø 18 mm
Tube Aluminium 7075 T6
Piston Dual piston ø 46 mm Assembly Ball bearing / ball bearing
or strut
Strut Steel ø 59 mm
Aluminum bracket
Aluminum internal cylinder Sliding with mobile bushes
CAS system YES
Adjustable hydraulic
compression bumpstop YES
Hydraulic
rebound bumpstop YES
About the CAS system
Your CR 60 dampers feature the CAS system Bos Engineering.
The CAS system increases the rebound speed : when the wheel is not in contact with the ground, it makes it going down faster. Therefore, the wheel is actually searching to come back quickly on the ground, which improves traction.
This system is not adjustable, and doesn’t require any specific maintenance from the user.
Maintenance,
and inspection
After each race week-end :
Wash and clean externally your dampers with a non aggressive and non alkaline product. Dry it and spray it with a soft and oily solver.
Be careful not to use a pressure system as Karcher especially on the top of the damper (particularly when the damper is without top caps).
Every 750 km
:Remove the dampers from the car; wash them completely before sending them to BOS-engineering, with the top caps fitted on, for “basic rebuilt” (see page 9 for details).
Every 1500 KM :
Remove the dampers from the car wash them completely before sending them to BOS-engineering, with the top caps fitted on, for “complete rebuilt”.
Inspections are detailled on page 13
Upper nut - top plate - M16 X 150 40 Nm Preloader blocking ring screw M6 5 Nm
Specific check and simple
maintenance of the strut
BOS dampers integrate a specific design of the strut that needs a special maintenance.
Please note that the oil inside the strut is only used to lubricate the cartridge. The damper inside the cartridge is completely isolated and independant. You could eventually notice some spray of oil through the air filter at the top of the damper assembly which is not considered as an issue.
Maintenance :
Every 350 kms the strut has to be inspected and the oil level reset throught the bleed screw (picture), with BOS AMX3 oil.
The oil quantity is 200 mL.
IMPORTANT
The damper assembly should never be placed or stocked horizontally unless the top caps are fitted to close the vent holes.
Base rebuilt
Complete rebuilt
made for
Low mileage, casual
race, normal race
conditions.
High mileage, frequent
race, demanding race
conditions.
Maintenance
details
Cleaning, disassembly,
re-built, drain and
oil change, general
inspection, change of
worn parts and seals,
final control
Cleaning, disassembly,
re-built, oil change,
general inspection,
change of worn parts,
linear bushings and
seals, top plate and
shims replacement,
main piston control,
final control, test on
the dyno to validate
and verify that the
characteristics are
staying in a tolerances
defined for each
product.
Frequency
(Km)
750
1500
or
once a year
Contact
[email protected]
Before sending your dampers, print, fill and send to BOS-ENGINEERING, your inspection form, downloadable on http://www.bos-engineering.com.
Please find the details of each inspection carried over at BOS factory:
Détail of
inspections
22
Your dampers
Your dampers are delivered with a hydraulic setting tuned for your vehicle and identified by the setting number. With this setting you get the basic adjustment in HS/LS and rebound. Those details are shown on stickers glued on the reservoir of each damper. We advise you to write these elements in the table below that you can use as reference during your test session or before sending your dampers to BOS for maintenance operations.
Serial number Setting number Basic settings (LS-HS-Rebound) Front damper 1
Front damper 2 Rear damper 1 Rear damper 2
Use the table below to note the adjustments that you do in test session or during the race season.
Session (date) dampers L.speed comp H.speed comp rebound Front set
Rear set
Session (date) dampers L.speed comp H.speed comp rebound Front set
Rear set
Session (date) dampers L.speed comp H.speed comp rebound Front set
Rear set
Session (date) dampers L.speed comp H.speed comp rebound Front set
Rear set
