i just installed my s/c this weekend 1st timer i dont have all the fancy gauges yet but it just seems like something wrong .im only feeling boost from 4-6k rpm i dont know if this is normal or not but thats not the worst of it .when i take off its ok in first still not really better than stock ,wacks 4 -6 k rpm then hits 2nd ,slowly gets up the rpm to get to boost for second,and so on .through all of them it really feels like its holding back to get the rpm up.is it the fuel pump i didnt put in ? or is something that might be going on that im just novice about ,id appr any pro opinions or sugg. thanks ,im going to change to the 255 walbro fuel pump tonight .its a vortech s/c on my 6.0 ,i dont know yet what the stock boost is on my s/c.its just holding back all through the rpm range.

 

You need to get that fuel pump on.

You need a boost gauge.

You need data logging ability and tuning ability.

Without the above you are rolling the dice every time you get into boost.

 

Honestly, until you get the ability to give us some more information there really is no way to help you out.

CHarris pretty much spelled it out.

Also, like I mentioned in your other thread, centrifugal superchargers don't build a lot of boost down low. They tend to make more boost higher up in the rpms.

 

Also as stated earlier.....centrifugal chargers dont make boost down low. If you are running a stock converter it wont feel like much down low either. If you are running a base non intercooled Vortech it is probably set up for just 6 psi and you will only see that at the top of the rpm's.
Get a fuel pressure guage and boost guage. You may find it's doing all it can in its current configuration.

 

Like others stated need more info...

Are you running stock tune injectors and an FMU?
Is it intercooled?
What PSI?
Even rear gearing can affect it especially a centrifugal charger that needs RPM to make boost...

On my Procharger the stock install was less than impressive until 4K RPM and up... The best thing I ever did for my truck besides 4.88 gearing, was ditch the FMU and crappy Procharger fuel pump, got 43lb injectors (marine injectors), 255lph walbro inline pump and a custom tune with the TM removed... If you are in fact running the stock tune and FMU, your likely way lean (you must have at least a fuel pressure gauge to tune in the FMU if you have one) and the torque managment is probably pulling all your timing down low trying to save the tranny, not to mention if your running a 6lb pully you aren't getting much boost below 3K... My 9lb pulley gives me about 3-4lbs at low RPM's, and 5+ above 3,500, and builds steadily to 9lbs right before the shift (that is the nature of centrifugal)...

Get some gauges, at least Fuel pressure and boost, and be carefull getting into boost until you can monitor it...

My $.02...

 

yeah it sounds normal to me. You need a stall and smaller pulley to make boost down low. Get all the other junk everyone else told to do.