Blownoiler
Registered User
That's an interesting project experience you went through. How is it you were getting 4psi at idle and not much more at higher rpm? It seems like that much boost at idle is unnecessary and inefficient. I'll have to do some reading. I don't know a whole lot about the supercharger you used.
Leakage between the rotors and case is normal at low speed in these rootes chargers, I don't know if the magnussen charger is different or not in this regard. I was fine with 4 pounds of boost at idle, it made for good cylinder filling which leads to a good clean burn (remember I was using veg oil for fuel most of the time- and I retarded the camshaft timing to shift the torque curve higher up the rev range-the later closinjg intake valve allowed a small amount of reversion at the end of the intake stroke so dynamic compression at idle was a bit lower than standard). 10 psi boost was available if I kept the v belt tensioned enough to avoid slippage, the boost jumped from 4 psi at idle to 8 or 9 pounds at about 1400 revs from memory, (EDIT....I bypassed some of the charge air to run the engine at lower boost levels to see how it would affect engine temps/big end bearing wear) taking off in 1st gear nearly gave me whiplash, so often I would take off in second gear at the risk of burning the clutch plate out. Honestly it felt like there was a much bigger engine under the hood. Acceleration from 2500ish to 4000 was about the same as the turboed performance until I retarded the camshaft, but I didn't find enough spare time to try many other mods so didn't perfect the setup. The Toyota S.C.14 is a crap charger, the shaft bearings are held in the case by some type of epoxy/plastic surround, so overheating the charger by using 14 plus pounds of boost is a no-no, these chargers came out on Japanese delivery luxury car petrol engines, and had a clutched serpentine belt drive as the petrol engined setup only engaged the charger at full throttle, the rest of the time they were bypassed. I knew that they were a poorer quality charger than many others before I purchased it, but at less than $500. delivered to my door (secondhand imported) I couldn't resist the temptation to try one out. The charger puts out 1400 cc s of air with each revolution, so was sized about right for the 2.4 litre diesel engine which has a redline of 4000 revs. Have you done the mathematics to work out how fast you have to spin your charger to get the lb.s of air required for your expected performance level?
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