I am not burning, using, or spraying oil via any crank case pressure. I just believe I aquired a leak out the back of my manifold because when I deleted alot of the recirc air/egr compontents I eleminated some things that properly equalize the crankcase pressure. The only thing I really had was a k&n filter on the passenger side valve cover that became saturated after a few hard pulls. I'm wondering if adding the throttlebody ventelation for the pass valve cover would provide the vacuum necessary or just inject oil into the TB.

All in all, I just want to get the problem solved so I dont have to replace the manifold gasket more than once.

I'm using the stock Vortech harmonic balancer mounted pulley (the one shaped like a flower pot). I have installed a 2.75in pulley and shift around 6500RPM (Is this what you recomend? )Thank you for any calculations you can add. I looked for calculator but had no luck.

 

I used my smog pump so it blows air into the crankcase. I was immediately able to find all my crankcase leaks.

 

Did you use it as a trouble shooting measure while the car was off or as a preventative measure to fix the problem?

 

This statement right here tells me you haven't read enough or searched enough in the forced induction section. Otherwise you'd see what everyone else has done and why and not be combative towards the people trying to help you. ILL SAY IT ONCE MORE. You DO NOT have adequate crankcase ventilation. If you hook up the breather from the pass. v. cover you will force even more press. into the crankcase while under boost, think about it. Also, your pcv valve may not be sealing properly under boost, allowing press. to leak into the crankcase. You need to suck the press. out under boost either by an exhaust evac system, an air pump, or a suck-side evac system plimbed into your v. covers. You will blow all your seals out if you dont right this now, including blowng the dipstick out of the tube if you try to seal everything tight. You ARE NOT going to seal the engine up without relieving the extra press. created from normal blowby under boost. There are numrous threads related to this topic and how others decided to go about fixing this issue. DO A SEARCH! Just about everyone here thats going to tell you how to fix the problem has already been down this road, including me.

On another note, I have an s-trim on a well breathing 350 and its almost pullied out with an 8rib setup, no slippage that I can tell, and Im only seeing 12psi on average with 15 on a cold day at 6500.

 

Here is the formula for impeller speed:

Impeller RPM = (Crank Pulley Dia.) X (Internal Step-up) x (Engine RPM) / (Blower Pulley Dia.)

I'm going to assume you have the 6.66" crank pulley. I'm also going to assume that V1's are still 3.45:1 gear ratio (new ones could be different?)
See max rpm by model here:

http://www.vortechsuperchargers.com/scspecsheet.php

**Note: Older S-trim's have a lower rpm limit @ 50K. **

6.66 x 3.45 x 6500 / 2.75 = 54,309 blower RPM
6.66 x 3.45 x 6500 / 2.55 = 58,589 blower RPM

Over-spinning is not necessarily a forbidden thing. Race cars do it all the time. Durability is one possible concern and should be well thought out if you're going to do it. The advantage is greater peak boost and more importantly, greater area under the power curve because at any given rpm you will have higher impeller speed. The disadvantage is again, some level in unknown reduced reliability and running outside of the efficiency range of the compressor (added discharge heat).

This also assumes one additional liberty...can you guess it?

0% belt slippage! How likely is this a reality? Even 5% slip at max rpm brings the 58K down to ~55K. But of course this value is assumed unless you can directly measure blower speed. So you 'technically' over spin the blower X amount, ***-u-me you get some amount of slippage, but rest assured you have more area under the curve which makes for a way better streetcar.

http://www.aspracing.com/index.html can make you a 2.55" blower pulley. Pretty sure these guys can make any size you want.

But first - you need to confirm your crank pulley diameter. As I remember there were 3 offered (could be different now) 6", 6.66" & 7" and also that Vortech is still using a 3.45 step up.

Have fun,
Scott

 

do you have a picture of your vac pump set up ?

 

External Vac pump works the best for me. I've tried them all. My experience is that the LT1 has alot of ring blowby with the design of the crankcase. Plus, the result was more cylinder pressure. I had to move the rad forward, so, some of you may think this is too much fab work. I also used Evans NPG coolant (evanscooling.com).

I had to design my own Vac pump air receiver with an oil feed-back line to lube the pump vanes. I purchased the pump from GZmotorsports.com. Their oil receiver did not work that good for me, so, I made one that uses centrifugal force. I fit it into the front bumper area since there is limited space in the 4th gen motor compartment.

I did not mod the front of the LT1 intake manifold fo oil leaks (just the rear). Usually the oil moves to the rear with forward vehicle acceleration. I've never had a leak up front.

I got alot of mods, and, mods require money. Good thing I have my rolling experiment to vent my Engineering/fab abilities, and, plenty of tools.

some pics.
http://s306.photobucket.com/home/mzgp5x