Okay I have a completly stock lt1 engine rebuilt 8k ago. I wanted to eventually run 12 pounds of boost on my set-up when I have the engine built up when I get cash. My question is If I bought the 10-14 psi p600b whats the lowest boost you can run 10 psi?? Or could I run 6-7 psi for right now on the stock engine to last for a summer or two. Its just when I have the engine built up I dont want to buy a bigger head unit. I was just confused it said 10-14psi. You could run a lower boost thow correct??

 

to run lower boost, simply just change out the blower pulley to a larger pulley this will effective give you lower boost you want.

Bruce

 

Correct...Just change the blower pulleys. I ran just 6psi on mine when I was on the stock engine. Although the P600b probably will not do more than 12psi on a 350... even less on a stroker. If you are aiming for 14 psi then I would go for a D1.

 

Sorry for the confusion I'm only going to 12# enough to put me into the 500rwhp range

 

Good luck trying to make 12 lbs of boost out of a P600b on a built motor. Not trying to be an a-hole but you really need to do a search on things. There is alot of great info out there. Alot of your questions have been answered plenty of times.

My opinion would be if you do not have the money for a rebuild than I would honestly not put a blower on your car. I am not trying to scare you but the majority of people that I know usually rebuild their motors a few months after installing superchargers. On the other hand I have a friend who has beat the hell out of his car for 3 years and it still runs strong. The choice is yours.

 

You have a point there. I might just go the other way around have the engine built first,take care of the rearend,etc. Have everything ready and last but not least slap on a procharger.

 

Im running 9lbs with my p600b. The motor has seen 15lbs before of course with different pulleys. The blocks a .030 lt1. I thought it says on the ATI web site the p600 are good to 20+lbs?

 

Okay, time for boost 101 (you guys with more experience correct me wherever I am wrong as I am not a master, but merely a grasshopper). Boost is resistance to airflow. A motor that flows well will show less psi boost, but make more power than a motor that does not flow well but makes more psi boost for a given compressor speed. The airflow is backed up in the intake tract creating pressure, this is boost. Don't get caught up in boost numbers, cfm airflow is more important. In the example above, the motor is .030 over so has a larger c.i. displacement than a stock motor, so, all things being equal, it will see slightly less boost pressure even though the s/c is putting out the same airflow; a stroker motor would see less, reduced compression would see less, just adding headers can increase airflow so would see less back pressure in the intake, cams can reduce back pressure....many variables. Now here's a brain stretcher...12 psi with a D1SC is the same as 12 psi with a P1SC or P600B on the same motor. The pressure in the intake is the same and the same power will be made. The difference is that the D1SC will make that amount of boost pressure at a lower compressor rpm than the P1SC, the P1SC will make it at a lower rpm than the P600B, etc. If you spin them all at the same speed, the D1SC will make more boost than the P1SC, the P1SC will make more boost than the P600B. However, due to restrictions in the flow path (intake, heads, exhaust, cam profile, etc.), the D1SC may not make any more power than the P600B because the motor is not capable of flowing any more air. You can get a bigger s/c, spin it faster and make 50lbs of boost, but the power you make is directly proportional to the amount of air the engine will flow. To make power using FI, you need to determine how much power you want to make, where in the rpm range you want to make it, how much airflow is needed to make that power, then get all the go fast parts that will get you there. Pay special attention to the heads and cam, they are the brain and lungs, if they work well together, most of the other restrictions (intake and exhaust) are just bolt-ons and can be swapped out if it is proven (or suspected) that they are the restriction to the airflow path. That is the mechanical/volumetric efficiency side in a nutshell, but there is still lots more to it, each with its own set of variables and solutions; bore and stroke, air intake charge temps, tuning (fuel and spark calibrations), etc. Then there is the philosophical side...how much is enough? For most of us, once we reach our goals, we want more; it's like crack.
Welcome to the money pit.
I wonder if there is a 12 step program for FI addicts?

Good luck,
Tom

 

Tom,
Good job on the write-up.

One thing I'd like to elaborate on is 2 chargers at the same boost can produce different power levels due to the different efficiencies of each unit.

More efficiency means either less HP required to turn the charger or cooler air being produced at the same boost level. It's free HP either way.

 

Thanks, Lonnie. I agree, there are different efficiencies between compressors, impeller trims, etc., I just didn't want to get too granular or I would still be typing it out. Just wanted to give an overview and see what kind of questions (if any) it generated and go from there. I would like to encourage everyone that may be considering going FI to continue to ask questions and read as much stuff as you can find in the various forums, that is how we learn. I like picking other, more experienced guys brains and having mine picked as well, that's why I am here browsing these forums. While FI is not rocket science, to do it right, it does require a certain amount of research and knowledge. If rushed into or done haphazardly, at best you won't get the results you want, at worst you will damage your engine and be out a lot of $$$.
I am sure we will be talking again and I look forward to it.

Tom