Magnuson Supercharger

S/Cs are fixed RPM, I've seen exhaust mods lower boost readings because of the VE increase (not a bad thing, a good thing), or you could have a vacuum/boost leak somewhere, even small. What exhaust setup do you have? Are the 2nd gen setups known to have belt slip? (First gens are)

 

What does your "butt dyno" say? Can you feel the extra HP?

In having a hard time getting worked up over your loss of a bit of boost.

It's a truck, not a Porsche.

If you can tow better or pass quicker, isn't that a win?

So your dyno numbers don't match the advertised numbers, can a person reliably use that missing HP and torque?

 

That's an oiled filter too right?

 

I do have a Magna flow cat back, but I wouldn't think it would rob me of a full pound of boost.

 

I get all that. I worry that something isn't right. i.e...if it's belt slippage, then i'm ruining my belt correct? If it's a pulley thats not spinning freely, then what am I hurting here...know what i mean?

 

Yes.

When I purchased the TRC SC the kit came with an oiled factory drop in air filter for the OEM intake.

 

I wouldn't think so either, getting rid of the cats is the big one for lowering boost due to lowered back-pressure. Maybe not enough tension on the belt? Maybe just get a URD pulley.

 

Few yrs ago
Long tubes, urd ypipe, 3" urd exhaust.... 6.5lbs boost at sea level, stock pulley.

 

Snout pulley connects to crank pulley..... engine isnt fixed rpm, so...... blower is fixed rpm?

 

Yes, but you can use 2010+ FJ Cruiser/4Runner OEM dry filter too.

 

Similar experience here - first installed SC got 5.5 psi that faded to 5. Added 2.85 pulley and it bumped to 6. Added CAI and it bumped to 7.5 than faded to 7. Seems there're multiple variables going into the boost number.

 

The fading thing seems odd.
Your peak numbers dropped over time?

 

You got me man, all this time I thought a flux capacitor torsen hybrid clutch type dynamic cvt pulley system with fairy dust dynamic traction coating kept the S/C's RPM at a constant RPM despite engine RPM, thanks for opening my eyes. I think you know and the OP knows what I meant- the S/C on his truck at X RMP should be spinning the same as any other OEM S/C at X RMP on other people's truck.

OP you bought this brand new? If there is any wear and bearings allow some play, the screws can wear on each other. I bought my truck used with lots of miles on the S/C, took it to Magnuson for a rebuild and it needed more than new bearings, they put in new screws due to wear/it wouldn't seal as well. I still need some fairy dust traction additive for the belt.

 

Yeah, a half pound. I'm wondering if it has something to do with an initial buildup on the air filter since the high number each time was with a brand new filter.