TSB 09-03-97 1994 Dodge Viper

coony

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Breathers, huh? I guess this engine has been modified from the stock system with PCV. Are those breathers open to atmosphere, or going to the intake ducting somewhere; any chance the crankcase is getting pressurized by the supercharger?
3 breathers…one on each side of the valve covers and one coming off of the oil fill cap. The supercharger replaces the manifold, so there is no PCV valve at that point. I actually just replaced the PCV valve, which was capped off since it’s not used with the supercharger, with one of the 3 breathers. I’m hoping that helps.

I’m going to try what Mobile Dan suggested and see how that works with the added breather.

Roe Racing, who makes the supercharger, responded and suggested putting the additional breather in place of the PCV valve since it’s not used. That should relieve additional pressure built up at high RPMs.


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billr

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Put a pressure gauge in place of the dangling PCV and see what pressure is reaching in the crankcase.
 

coony

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may I ask what chip is in it

inquiring minds want to know;)o_O
The supercharger has it's own stand alone ECM/Engine Management System. It works in conjunction with the original PCM and is tuned specifically to this vehicle. The supercharger and Engine Management System are both from Roe Racing. Unfortunately, the system is no longer available/serviced, so if it ever fails I will need to wire in a new ECM and retune everything. I don't see that happening, unless the Engine Management System were to get wet. However, I do not drive when it's raining, so that won't be a problem.
 

coony

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Well, I'm still getting oil coming out of both the bottom and top of the dipstick tube. So, now I will need to figure out why there's so much back pressure. I will get a compression/leak down test done soon to see if there's any issues there. If not, I'm thinking my only other option to relieve the pressure that builds up is to install a vacuum pump.
 

billr

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Rather than looking for excess leakage at the pistons/rings, I would suspect leaking at the intake ports into the valve-valley. You already have a huge vacuum pump (the engine), use it with a proper PCV system. Maybe bigger breathers, too. The "cone" filter that I think I see on one filter is kind of restrictive. Do the others have the same, hidden from view?

Again, I would use a pressure gauge on the crankcase to get some clue as to what, if any, pressure is building up.
 

Mobile Dan

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I don't know much about superchargers. Does it have some sort of pressure relief valve for a high rpm/closed throttle situation? Where does the unwanted pressure go? Or, is there a clutch on the pulley to disengage the supercharger sometimes?
 
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