This supercharger was tuned with 520cc CT supplied injectors and pulleys. The
belt tensioner system was a prototype system using an automatic tensioner. A
belt length of 1897 mm worked with all pulley sizes from 3.3 to 3.0.
TSX specification:
2004 TSX MT
06 TSX intake camshaft
64mm 06 TSX throttle body
45 degree VTC pulley
Injen CAI
Hitech header, Exhaust and highflow cat
Stock head, block, clutch and gearbox
Boost levels
This graph shows the boost levels with 3.3, 3.15 and 3.0 pulleys. VTEC point
3000 RPM. Boost levels vary according to cam angle and VTEC point. As you can
see here the boost level drops by about 1.5 psi at VTEC point, but the power and
torque increase as the engine is breathing more efficiently. If you retard the
cam angle the boost will increase and the power will drop. This is because the
air is being trapped in the intake where the MAP sensor is located rather than
finding its way into the cylinder.
Power and torque for 3.3, 3.15 and 3.0 pulleys.
Do I use the stock cam pulley or machine a 45 degree VTC pulley
The optimal cam angle for maximum power and torque involves advancing the
camshaft to 45 degrees at the VTEC point and retarding to 30 degrees at redline.
We compared this to holding the cam angle flat at 25 degrees to simulate a stock
VTC cam pulley.
The power and torque difference between the two is very small. 3 ft-lbs of
torque and 3hp. The midrange boost difference is large - 2 lbs of boost. Higher
boost levels will mean that intake temperatures will be higher. This also
indicates indicate that further cam testing is necessary. What might be
happening is that the large exhaust cam lobe of the TSX combined with the 45
degrees intake cam timing might be causing blow-through, in which a portion the
intake charge is being blown straight out the exhaust. This could indicate that
a smaller exhaust cam - say that from an RSX-S might be worth a try.
So, for your supercharged application you could stick with the stock VTC
pulley and see great results.
Red 45 degrees at 3000 rpm declining to 30 degrees at 7500 RPM
Green 25 degrees from 3000 rpm to 7500 RPM
Possible Improvements
There is a fairly sharp turn from throttle body to supercharger intake. At
wide open throttle the butterfly extends into the area the air needs to make a
turn, possibly restricting its flow. At the marked point (red arrow) the air
pressure was measured. 0.7-0.8" of vacuum was measured from about 6500 rpm
to redline. This is about 2.5% of atmospheric pressure. 2.5% of 330 HP is
about 8 HP, so I predict you should be able to gain at least 5 HP in this area.
Ideally a new throttle body mounting flange with a straight air path to the
supercharger would be manufactured, but you would need to redo your air intake
piping. Note that an 06 TSX with the larger 64mm throttle plate will be more of
a barrier to the air turning.
One improvement would be to space the throttle body out to provide more room
for the air to turn. Note that once you bypass the water heating to the throttle
body (recommended), a thermal spacer will provide no additional cooling.
From Start to Finish
This is our 04 TSX when completely stock compared to its current boosted
configuration - a gain of 152 hp and 86 ft-lbs of torque.
The dyno runs were done with a velocity stack as the stock
intake air filter needed cleaning.
