Need Supercharger Help

SCaddict

Registered User
I am having a problem building boost at higher RPMS. I build about 10psi at about 2500rpms and then about 11psi by 3000rpms. After that I do not build anymore boost at all. I am overdriving the blower by 15% and I am not having belt slippage problems. Any thoughts would be great.
 
I would imagine you have a vac leak somewhere, maybe you can find it with a can of ether... might be hard if the leak only occurs during higher boost...

There was a thread some time ago about going through and using clams on all of the vac lines being good for squeezing the max amount of boost. Seems like the author of the thread posted an acutal gain in boost after doing this...


Not to get off topic too much, but how is that 15% working for you, other than the current boost problem? Do you think it is working OK?

I have a 5% jackshaft on the way, and already have a 10% blower pulley, I also have a double IC being made (aready have a IC fan). I am toying with the notion of using them both... Do you have any problems with pinging? Have you tuned the car since the 15% OD?

After secod though, I bet you will be smokig after that snow kit :cool:
I'm still hoping to fit one in my buld somehow...

One more thing, that 14.7 was before these mods, correct?

Thanks!
 
The 15% is working fine. It helped me reduce me 60' times by a couple tenths and run my quickest time. The 14.7 was before all the "In the works stuff". I have never had my car tuned and I had a major problem with pinging until I figured out that a gas station by my house is selling 92 fuel that I now believe is NOT 92. Now that I am running other fuel it is gone. I think with the top, FMIC and the Snow kit the car will have much more power to it. I am hoping for about 50rwhp out of the whole deal. Maybe not but I will see.
 
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SCaddict said:
I am having a problem building boost at higher RPMS. I build about 10psi at about 2500rpms and then about 11psi by 3000rpms. After that I do not build anymore boost at all. I am overdriving the blower by 15% and I am not having belt slippage problems. Any thoughts would be great.
Sounds like the bypass is opening. Probably a bad diaphram or a vacuum leak on the line that goes to it.
 
Marty,

I also think it's the bypass valve not closing all the way. The linkage can sometimes bind against the back of the supercharger. It uses vacuum to hold it open and spring pressure in the diaphram to close it. To make sure it's closing all the way remove the vacuum hose with the motor running or inspect the linkage and valve position with the motor off.

David
 
I just checked it and the bypass seems to be working fine. On idle the valve opens all the way and when I pull the vacuum line it closes on to the screw. Checked the linkage and it is fine also. Could my altitude affect it that much? Maybe the blower is worn? Could the rotors be out a little?
 
David,

I thought that too and was looking at it to see if I could set it. The screw is out about 5 or 6 threads. I was told that if it is not set right that the valve could open the wrong way. How can I adjust it?
 
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