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There is no need to go into great detail about the virtues of strut bars (braces).
It is universally accepted that strut bars help to counteract the flex caused by vertical suspension loads being transmitted to the top of a vehicle's strut towers relative to the rest of the chassis.
Strut bars are designed to reduce strut tower flex by tying two parallel strut towers together. This transmits the load of each strut tower during cornering via tension and compression of the strut bar, which shares the load between both towers and reduces chassis flex. A direct result of this is improved chassis rigidity, reduced understeer, improved tire wear, and metal fatigue is greatly reduced in the strut tower area. Following the aftermarket's lead, many manufacturers fit strut bars to performance models as standard equipment.
At first glance under the hood of a P2 S60/S80/V70 it would appear that Volvo was thoughtful enough to install a strut bar from the factory. However, upon further inspection you realize that what looks like a very beefy strut bar is nothing more than an overly complicated engine mount. More specifically, this engine bar serves no other purpose than to provide something for the engine torque mount to bolt to.
In Volvo's never ending quest to dampen the engine, they designed an overly complicated engine mount system using four different rubber mounts for the top mount alone! The actual upper engine torque mount is comprised of 2 separate rubber torque arms/bushings attached to the engine bar. That is more than necessary, as Volvo has been using the same basic engine torque bushing design for decades. The problem is that the ends of the engine bar itself are mounted in rubber as well! This translates to a large amount of fore/aft and left/right movement in the upper engine bar as well as the whole engine mounting system. The net effect is that engine and transmission performance is lost through this unnecessary and excessive engine movement.
The following video illustrates the movement of the stock engine bar:
Other companies offer tiny polyurethane caps that insert into the engine bar mounts, which attempt to limit some of the unnecessary engine movement. However, due to their small size and the engine bar's design, these tiny poly inserts only limit a small amount of the engine bar's movement. The inserts deform easily in the under hood heat, and will break down further with age. Clearly a better solution was needed.
Quickbrick Motorsports has developed that solution in the form of complete replacement mounts. These mounts serve a dual purpose:
- First, the QBM mounts eliminate ALL of the engine bar's unnecessary movement. The QBM mounts still allow the actual engine torque mounts to do their job and work properly. But by limiting all of the engine bar's movement, engine power and control is maximized and transmission shifting is much smoother!
- The second and most important purpose of the QBM mounts is that they actually convert the engine bar into a STRUT bar.
Aftermarket strut bars are available for the P2 vehicles, but they are made of weaker aluminum and do not serve the dual-purpose like the QBM Strut Bar Conversion. They also weave and bend multiple times around engine components as well as the engine bar itself. The result is an strut bar that compromises performance and proper strut bar design due to packaging and space constraints. The QBM Strut Bar Conversion doesn't add extra bulk under an already cramped hood with an ineffective add-on strut bar.
The reason why the QBM Strut Bar Conversion works so effectively
is simple. The Volvo engine brace is constructed of heavy-walled
steel. It's extremely stiff and perfect for a strut bar.
It spans the centers of the strut towers, and is perfectly
straight. These are optimal design elements of proper strut
bars.
Compare the video of the engine bar with the stock mounts
from before with the engine bar after it has been converted
using the QBM P2 Strut Bar Conversion:
Before (Stock): |
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QBM P2 Strut Bar Conversion: |
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And don't assume this conversion is for
racing purposes only. It was designed and long-term tested on an everyday street driven vehicle, and is perfectly suitable for the street or the track. The driver of our test vehicle has no complaints about harshness or
vibration. Quite the contrary. The crisp handling improvement of the strut bar was a welcome change over the stock vehicle.
Do not assume that ANY stronger or solid mount will
automatically increase cabin vibration. Some Volvo owners base
that assumption after having fitted their cars with a
polyurethane engine torque bushing. When adding a polyurethane
engine torque bushing, there is an increase
in cabin vibration. However, our Strut Bar Conversion
does not interfere with the stock engine torque arm bushings.
This is due to the fact that the engine mount system uses
four different rubber mounts for the top engine mount
- the large engine torque bushing, a smaller secondary
torque arm bushing, and the two engine bar mounts. Even
though you are replacing the two engine bar mounts with
the QBM Strut Bar Conversion mounts, the
two primary engine torque bushings, which are in reality the main engine mounts, remain untouched. The two remaining engine torque bushings are same two mounts that Volvo
has been using on it's cars for decades. This is why there
is no difference in cabin vibration with
our Strut Bar Conversion.
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