I landed a used JRSC for my track car and wanted to give it a shot but ran into some trouble...hoping someone might have an idea.
The blower was used and the snout bearings didn't sound good, the bypass actuator was shot as well, so here's what I had done:
- new snout bearings/seal
- new snout to rotor coupler
- fresh oil in the snout (of course)
- new bypass actuator
After this, I could tell there was no play in the snout and the rotors appeared to move smoothly.
I went ahead and installed the kit along with 42# injectors and loaded a base SCT boosted tune (I ran the SCT on a turbo car for a long time so got familiar with fuel/timing work). Fired it up and everything seemed fine. Blipping the throttle engaged the actuator as expected - also no strange sounds from the blower. Figured all looked good so I took the car for a spin and that's where I got my disappointment - there was nearly no difference in power, actually the power output possibly dropped slightly due to the timing being pulled in the tune. I observed nearly no boost at the same time - maybe 1-2psi. Brought the car back and looked through everything - I see no obvious vacuum leaks. Also looking at my datalog from the run, the air-fuel is spot on using the same MAF table from when the car was NA - which tells me I'm not likely leaking a lot of air - in addition to this I also don't see my load or MAF counts go much higher than when the car was NA - at most I see the load going from ~0.9 when NA to 1.0 with JRSC. Something's very much off...
Any ideas what could cause a JRSC (or more generally a roots blower) no produce boost if the bypass actuator and valve are good, snout is good and there don't appear to be any vacuum leaks?
The only other thing I could think of is that the rotor clearance is super off but I'd expect to be hearing some crazy noises from the SC for that.
Really appreciate any ideas y'all could offer.
The blower was used and the snout bearings didn't sound good, the bypass actuator was shot as well, so here's what I had done:
- new snout bearings/seal
- new snout to rotor coupler
- fresh oil in the snout (of course)
- new bypass actuator
After this, I could tell there was no play in the snout and the rotors appeared to move smoothly.
I went ahead and installed the kit along with 42# injectors and loaded a base SCT boosted tune (I ran the SCT on a turbo car for a long time so got familiar with fuel/timing work). Fired it up and everything seemed fine. Blipping the throttle engaged the actuator as expected - also no strange sounds from the blower. Figured all looked good so I took the car for a spin and that's where I got my disappointment - there was nearly no difference in power, actually the power output possibly dropped slightly due to the timing being pulled in the tune. I observed nearly no boost at the same time - maybe 1-2psi. Brought the car back and looked through everything - I see no obvious vacuum leaks. Also looking at my datalog from the run, the air-fuel is spot on using the same MAF table from when the car was NA - which tells me I'm not likely leaking a lot of air - in addition to this I also don't see my load or MAF counts go much higher than when the car was NA - at most I see the load going from ~0.9 when NA to 1.0 with JRSC. Something's very much off...
Any ideas what could cause a JRSC (or more generally a roots blower) no produce boost if the bypass actuator and valve are good, snout is good and there don't appear to be any vacuum leaks?
The only other thing I could think of is that the rotor clearance is super off but I'd expect to be hearing some crazy noises from the SC for that.
Really appreciate any ideas y'all could offer.