Recently installed a JRSC on my ITR motor in my crx and im having a lot of problems.


The car made 201whp/139 TQ All Motor. Only mods are my KiddRACING B Narrow Header, and Skunk2 Stage 2 (tuner series) Camshafts. Tonight on the dyno the car was making 4.97psi on LOW CAM tuning. . We start tuning VTEC and the SECOND VTEC hits the PSI drops to 1.5-2psi and holds. NO BELT SLIPPAGE that we can see or tell. On low cam it holds boost all the way, on VTEC/High cam it falls as soon as VTEC engages.

At first i thought maybe it was the Skunk2 Cam settings. I had the exhaust cam at +3 (from when i degreed them when the car was NA). I moved the cam gear back to 0,0 and the same problem was there. I also tried retarding the intake and advancing the exhaust and vice versa and same problem persists.

i measured the pulley and its a 4.2'' which IIRC is the 6psi pulley.

My theory is that my motor is wanting more air the higher it spins even in VTEC and the JRSC just isnt feeding it enough. I think the JRSC is bottle necking the engine. Seems to be more of a cylinder pressure issue than anything else. Seems like i need to spin the Charger faster or create more boost. So this 6psi kit is only good for 2ish PSI on my particular well breathing engine. Make sense?

Im going to try adding the B20 Crank pulley to get more psi out of it, will it fit the CRX clearance wise? Can i just add the B20 Crank pulley and not do anything else to increase boost?

This is my first Supercharged car, kinda frustrated. Im making less power than i was before lol

Here are the dyno graphs. Blue run VTEC is at 5500 and it drops psi the second VTEC hits. The green run VTEC is at 4000 with the same results.

 

With this type of supercharger, boost will taper off at higher rpms because the actual pressure in the manifold is lower, not necessarily because the charger isnt flowing enough. You can see this because boost drops off, while power holds steady. At higher rpms the engine is taking in more air than at lower rpms, where the charger is forcing the air in, as opposed to the engine sucking it in. At high rpms, the charger is still forcing in air, but since the engine is sucking in a lot on its own, the pressure between the charger and head will be lower.

Hope that makes sense, you already seem to have the theory down for the most part.

 

why am i not surprised, try some stock cams and see what that yields. The engine is all stock except for cams, in a normal setup...you wouldnt see that drop in pressure, it should be no less than 5 psi. The b20 pulley alone will raise the pressure, if you need a stepper pulley for the alternator let me know, i have a friend with 2 SIZES of stepper pulleys, one increases to 8 psi, and then the other is 10, add the b20 pulley and its 12.

 

Call me