VMAC
Features and BenefitsSystem Specifications
Operating Principles
System Operation
Routine Maintenance
Troubleshooting FAQ
Features and Benefits
UNDER-HOOD compressor system advantages:
- Approximate total VR70 system weight is 136lbs.
- Approximate total VR140 system weight is 206lbs.
- One lightweight tank/separator, easy accessible filtration, two filters in tank
- Patented low profile modulating high flow inlet valve with air filter.
- Liquid to liquid cooler, integral with vehicle cooling system (no need for electric fans).
- Cast aluminum mounting brackets easy installation.
- Fast customer support.
- Factory trained certified installers.
Engineering specification:
- Systems in production for most makes of popular light & Medium duty trucks. Each system is individually designed specific for the vehicle and is engineered in full collaboration with OEM engineers.
- Design of the drive system is done with calculation of belt tension load, and analyzed with software by major OEM belt drive manufactures engineers.
Bracket design:
- Digital measuring, Solid modeling and rapid prototyping are used to complete cast bracket design. Allowing quick accurate designs for new trucks on or off site.
- All designs completed in Solid Works
System design & testing:
- Up to 2000 hrs durability and life tests on new designs.
- Each system has CFM / RPM study conformation.
- Cast brackets are subjected to computerized stress testing to 10g and 600 lbs static load tests.
- Final belt alignment is checked by .010″ laser alignment.
- Completed system design is tested 8 hours continual running air system at various CFM.
- 100 kms highway driving all speeds.
- 20 kms off road testing.
- High pressure water aquaplane testing
- Belt behavior with high speed video camera mounted underhood.
System Specifications
Model: VR70 and VR140 UNDERHOOD Air Compressor
Type: Rotary screw
Drive System: Separate serpentine belt from engine crankshaft
Control: Electric on/off 12V clutch control
Maximum Air Delivery:
VR70 70 CFM and 175 PSI
VR140 150 CFM and 175 PSI
Pressure Regulation: Mechanical inlet control valve modulates flow in response to demand
Engine Controls: Throttle control to modulate between idle and upper limit RPM to maintain air supply
NOTE: Some trucks have onboard computers that must be programmed by the OEM dealer to permit operation of the electronic throttle control.
Safety Features:
- 200 PSI relief valve in oil/air tank
- Temperature safety sensor in compressor
- Rapid blow-down valve to discharge system pressure on shutdown (10-15 seconds)
- Drive disable circuit (DDC)
Lubrication: VMAC certified and approved synthetic oil
Filters:
Paper-type replaceable air filter
Spin-on type oil filter
Coalescing separator element
Operating Principles
Complete system includes:
- belt-driven rotary screw air compressor
- drive system
- air/oil separator tank
- oil cooler
- throttle control
- VMAC’s air-on-demand technology matches air output with air demand. As your tools require more air, the truck engine increases RPM to produce more air, matching your requirements. With rotary screw compressors, you can run 100% duty cycle and not have to worry about re-filling a bulky reservoir tank. This means you can use your tools without having to wait for your air supply to catch up. More uptime means your can accomplish more.
UNDERHOOD compressors use only a small air/oil separator tank that safely mounts on the frame rail of your truck. The rest of the components are neatly mounted under your hood so you save valuable weight and payload space. Not mounting a larger gas or hydraulic drive compressor in the back of your truck gives you more room for tools and other equipment.
UNDERHOOD compressors will run most of your pneumatic tools. You won’t need to drag a tow-behind with you that requires extra maintenance, fuel, insurance and ties up your receiver hitch. As work trucks are being used for more and more jobs, the room you save by using an UNDERHOOD system allows you to equip your truck for a wider variety of jobs.
Components:
VR Rotary Screw Compressor
Small, light and very powerful. Rotary screw compressors deliver more air than older, reciprocating piston style compressors. 100% duty cycle means more uptime. Driven by your truck’s engine gives you the advantage of not having to bring extra fuel to the job site, or maintain and insure a separate trailer just for your air needs.
Drive System
The compressor is driven by it’s own serpentine belt. The drive system is mounted forward of the OEM belt and uses idlers and tensioners to exacting tolerances. OEM drive systems have limited capacity for further horsepower draws and add side-loading to aftermarket pulleys. The VR drive system is designed specifically to match the horsepower and alignment of the compressor.
Air/Oil Separator Tank
Required to separate compressor oil from compressed air, the tank mounts safely to your truck’s frame rail. There is no need to mount a bulky receiver tank that takes up payload.
Oil Cooler
Liquid to liquid or air to liquid, depending on the system. The compressor cooler mounts in the engine compartment and out of the way.
System Operation
System Operation procedure:
- Prestart, Start Up and Shut Down Procedures
- Cold Climate Operation
- Automatic Shutdown
- Adding Oil to the System
- Adjusting the System
- Adjusting the Pressure Regulator
Routine Maintenance
The UNDERHOOD compressor system contains no reed-valves or other easily fouled, fatigue-prone components. With routine maintenance, the need for premature repair or element replacement can be significantly reduced.
Impact damage and premature bearing failure may occur in the compressor bearings if the system is not operated on a regular basis due to vibration caused by truck operation. Operate the system at least every 30 days for 15 minutes at no load to ensure proper bearing lubrication and rotation.
During the warranty period, you must follow the maintenance schedule and use only original genuine VMAC replacement parts to maintain your system and your warranty.
The most crucial aspect of maintenance is proper air filtration and clean oil. If any particles enter the compressor through the air inlet, they can contaminate roller bearings, gears and the rotors in the compressor. Contamination will cause severe, swift damage to components.
Never run the compressor, drive the vehicle or even allow the vehicle to sit parked without the recommended air filter and filter cover installed.
Maintenance Schedule
The following maintenance schedule should be observed to guarantee good performance and a long service life. The hours specified are those displayed on the Compressor Control Panel. Service should be performed at the lesser of the two intervals, whichever occurs first.
Always use a VMAC oil filter which is designed to withstand the high pressures, not an automotive filter.
50 hours:
Check the drive belt
200 hours or 6 months:
Replace the air filter, oil filter and change oil
Use service kit #A700019 (VR70)
#A700059 (VR140)
400 hours or 1 year:
Replace the air filter, oil filter, coalescing element and change oil
Use service kit #A700020 (VR70)
#A700060 (VR140)
Troubleshooting
Under Hood VR70 air compressor system with a
certified 70 CFM and 175 psi output.
This compact and high output underhood air compressor triples the output performances of the large reciprocating under hood air compressors and at least four times the output of those bulky gas drive air compressors.
- Up to 70 CFM and 175 psi
- 100% duty cycle
- Air on demand
- Compact design
- Light weigh
- Save vital workspace and payload
Applications
The Underhood VR70′s sleek design is nestled under the protection of the engine hood, allowing access to your air supply at any time. The Underhood VR70 high output, 70 CFM and 175 psi may eliminate those tow behind compressors that are sometimes too large of CFM for the job and impossible to get onto the job site.VR70 Underhood Air Compressors In Action!
There is no need for air restricting, unsightly and excessively heavy receiver tanks or gas compressors that take up vital work space.
The Under Hood VR70 air tank weighs only 21lbs and its compact design measures a mere 6.0″ in diameter and 31.0″ long.
The Under Hood VR70 air power system allows instant pressure and 100% duty cycle which eliminates the waiting time to fill a large receiver.
Underhood VR140 air compressor system with a
certified output of 140 CFM and 175 psi.
The VR 140 is the only Under Hood air system available on the market today capable of providing 140 CFM.
The VR140 provides more air for applications in municipalities, utilities, contractors, highway, maintenance and others that use large pneumatic tools.
Applications
In Addition to traditional lower CFM air tool requirements, the VR140 is ideal for operating rock drills, paving breakers, backfill tampers, and even sand blasting.
The VR140 comes as a complete installation package including the belt driven rotary screw air compressor, mounting brackets, oil/air separator, oil cooler and electronic variable speed control with only weighing in at an amazing 206 lbs.
FAQ
The UNDERHOOD Air Compressor is sold as a complete air system; the only thing you have to take care of is on the discharge side of the tank. These are the smallest most compact and highest output UNDERHOOD compressors available today. The VR70 is able to run a 1 ¼” impact or 60 – 90 lb Jackhammers. With this amount of air the UNDERHOOD Air Compressor is like having a small tow behind under your hood. The UNDERHOOD Air Compressor System was engineered with the service truck, tire industry, construction, mining, logging, utilities, and fire apparatus in mind.
Can you explain how the UNDERHOOD air system works?
What features does the inlet control valve have?
How is the RPM controlled on the UNDERHOOD Air system?
Does the UNDERHOOD Air System stay at one RPM?
How does the air/oil separator tank work?
What is the tank made of, and is it pressure tested?
Does the tank have any other features?
How is the UNDERHOOD Air Compressor System cooled?
How do you start the UNDERHOOD Air System?
Are there other safety features?
Can you explain how the UNDERHOOD air system works?
The UNDERHOOD rotary screw air compressor has 5 main components. The first main component is the rotary screw air compressor with inlet control valve. This small compact air compressor has two rotors, when the electric clutch is engaged the rotary screw starts to turn. The inlet control valve opens up to allow air and oil to mix between the rotors. The oil makes a seal against the inner walls of the compressor. The more air needed, the more oil flows into the throat to make a continuous seal causing compression of the air.
The engine on the truck will increase in RPM to approximately 2,000 rpm, this will last for 3-6 seconds. When the transducer senses that the tank is fully charged the transducer sends a signal to the throttle control to start to idle down to 900-1,000 rpms. The truck will sit at this rpm until there is a demand for air in the system.
What features does the inlet control valve have?
Some of the features are:
Easy to fill oil plug located on the top.
Easily removable air filter.
The air filter is a 5 micron paper element filter.
The pressure can be adjusted from 100 – 175 PSI.
How is the RPM controlled on the UNDERHOOD Air system?
The RPM is controlled by the Throttle Control. The electronic throttle control works with the transducer. This easy to install throttle follows the pressure drops in the air/oil separator tank. The Throttle Control automatically adjusts by increasing or decreasing the rpm of the vehicles engine to match the pressure drop. The throttle is a closed loop system so it is watching an rpm signal from the vehicle. By watching this signal this will insure that the engine doesn’t over rev. The Throttle Control rpm can be adjusted easily by turn the adjustment screw. There is low idle adjustment or idle down pressure screw. The settings you want to have are 900-1,000 rpm on the low idle and 1,800- 2,000 rpm on the high idle. On non-electric foot pedal applications, the RPM controlled by a pneumatic throttle control, which works when there is a drop of pressure in the system. A piston in the throttle is then moved by a spring-loaded piston to move the cable in or out which in turns adjust the RPM of the engine.
Does the UNDERHOOD Air System stay at one RPM?
NO. The UNDERHOOD Air Compressor System adjusts to the demand of the tool you are using. For an example if you were to run a 35 CFM tool the rpm on the vehicle would be around 1,100-1,300 rpm, once you take your finger off the trigger, the system would idle down to the preset setting of the idle down pressure adjustment. If you were to change the tool to a larger CFM requirement, the rpm would increase to match that the CFM demand of that tool.
How does the air/oil separator tank work?
The air/oil separator tank is a three-function tank:
1st it is an air receiver tank.
2nd it is an oil reservoir tank, because the UNDERHOOD Air Compressor is a flooded screw; oil is required to be stored for maximum use.
3rd this is where the separation of air and oil take place. Oil and air pass through baffles which knocks out a majority of the oil, the air then passes through the coalescing filter, which eliminates the rest of the oil before it is discharged out of the tank. If oil passes through the coalescing filter the oil will drop to the bottom of the tank where the scavenging system picks up the oil and sends it back to the compressor.
What is the tank made of, and is it pressure tested?
The Tank is made out of aluminum. Every tank that is manufactured is pressure tested to 350 PSI for 20 minutes.
Does the tank have any other features?
Other features are:
Easily assessable spin on oil filter
Sight glass to check oil level
200 psi safety relief valve
Rapid blow down cap
Aluminum spring-loaded sight glass cover.
How is the UNDERHOOD Air Compressor System cooled?
A liquid-to-liquid cooler cools the system. The cooler is located below the radiator, so there is no interference with the airflow to the engine. The vehicles hood must remain in the closed position when the system is operation so it allows maximum airflow. The coolant of the vehicle cools the heat exchanger. The cooling of the oil is self-contained so it is independent of the engine oil system.
How do you start the UNDERHOOD Air System?
There is a control box located in the cab of the vehicle. The control box has an on/off switch. When the control box is turned on an hour meter will light up, this meter only counts time when the air system is in operation. The control box also has an over temp light. The system will shut down automatically if the over temp light comes on.
Are there other safety features?
There are five safety features:
The first has already been mentioned which is the over temp sensor.
The second is the PARKING BRAKE has to be fully applied.
The third is the drive disable circuit; the DDC prevents the operator from starting the VR70 up in gear. The vehicle must be in park or in neutral before the system will turn on.
The fourth is the 200-psi relief valve. If pressure should build up in the tank that exceeds 199 psi the relief valve will release so the tank cannot over pressurize.
The fifth is the automatic blow down cap feature which will drain the tank of air once the system is shut down.