New 600b user (Questions and Intro)

[stuckatcuse]

Hi guys-

I just joined up. I have a 95 tahoe (TBI) with a 180 stat and a pacesetter exhaust. I just purchased (used) an intercooled p600b HO system with a 12 lb pulley. I installed it last week and have a couple of questions for the zen 600b gods.

1.
What is this thing supposed to sound like? Mine makes a chincy screetch at idle (like a real loud broken powersteering pump) and a smoothes out (a little) at higher rpm. If you listen real close (with your ear up to the thing) you can hear a dull 'dragging' sound (for lack of a better descriptor) at idle. It's not grinding, but not silky smooth either. It sounds kind of like a turbine under load. After a good run it's too hot to touch. Is this normal?


2.
I have the whole system installed but I'm only getting about 5 lbs of boost. I don't *think* I have any leaks, don't think the belt is slipping, and don't have underdrive pulleys. I'm worried that I got a bum unit that just can't produce the supposed 12 psi. My boost gauge is hooked up to a long run of vacuum tubing that goes to my surge valve and the MAP port on the throttle body.
I am wondering if some of the tubing is expanding causing either a loss in boost or false boost readings? Anyone have any tips? Is this problem correlated with question 1?? Please help?? I can't even break the tires loose. (I'm in the process of tuning right now. I need to scan a couple of WOT runs with datamaster.)

Any other tips would be welcome.

Thanks tons for any help.
Glad to be part of the forum
Sean

[pablo]

Dear new P600 owner:
Ok let ma address your questions:
1. the sound at idle is normal, most of the supercharges make a noise at idle, but the P600 is the lowdest, and you are right , it sounds like a bad power steering pump, and the sound goes away once you rev it up.
2. Before I say anything about your boost problems, I need to know your RPM engine limit and also the size of the pulley on the SC and damper.

Enjoy the boost!!!
Pablo

[stuckatcuse]

Dear new P600 owner:
Ok let ma address your questions:
1. the sound at idle is normal, most of the supercharges make a noise at idle, but the P600 is the lowdest, and you are right , it sounds like a bad power steering pump, and the sound goes away once you rev it up.
2. Before I say anything about your boost problems, I need to know your RPM engine limit and also the size of the pulley on the SC and damper.

Enjoy the boost!!!
Pablo

1. Sweet.
2. I have the 2.55" 12 lb pulley (According to ATI) I'm not sure about the diameter of the crank pulley. It's the stock one. (No underdrive, etc.) The redline is about 4500 RPM. ATI says it should only make 12 (i'd expect about 10) lbs of boost at redline. I've had it up to about 4100. I have a rich/lean spot under heavy load at high rpm. (it bogs a little) I am currently tuning it with datamaster. My current hypothesis is that w/ the dead spot in the fuel curve I can't rev fast or high enough to generate enough boost. I don't know if that's plausable. Thanks for the reply.

Sean

[pablo]

1. Sweet.
2. I have the 2.55" 12 lb pulley (According to ATI) I'm not sure about the diameter of the crank pulley. It's the stock one. (No underdrive, etc.) The redline is about 4500 RPM. ATI says it should only make 12 (i'd expect about 10) lbs of boost at redline. I've had it up to about 4100. I have a rich/lean spot under heavy load at high rpm. (it bogs a little) I am currently tuning it with datamaster. My current hypothesis is that w/ the dead spot in the fuel curve I can't rev fast or high enough to generate enough boost. I don't know if that's plausable. Thanks for the reply.

Sean

Dear Sean:
With the 2.55" SC pulley,the 4.500 rpm redline and a 7.67" crank you will see about 7 to 8 psi at the intake manifold without Intercooler.
Just make sure you dont over rev that p600b, the redline of the supercharger is 60.000 rpm.
Call ATI and have the serial number ready, the Supercharger pulley size and also the crank pulley size and the rpm limit of your engine, thjey would let you know how much boost you could expect.
Boost would depend on: speed of the supecharger and intake restrictions such as: intercooler, air filter, intake manifold design, heads, exahust manifold, and also some elobows on your intake system.
I doest not matter if you rev it up fast or slow, once you get that baby spinning at 49.000 rpm...you will enjoy the boost.
Take a time and meassure the boost at the outlet of the supercharger, so you will know how much boost you are making.
I hope this would help you.
Enjoy the boost
pablo

[stuckatcuse]

That sounds about right. I did some tuning today and leaned it out almost all the way. My O2 still reads 950mV at WOT. I am hoping to get it in the 850 range, but I don't know if its possible. My fuel trim is rich across the board. I think I may need to get an adjustable fuel pressure regulator for my tbi unit. Anyway, after redlining it, I got 7PSI, which is about right. But why would the kit claim 12 if the max I could ever get was 7?

[pablo]

That sounds about right. I did some tuning today and leaned it out almost all the way. My O2 still reads 950mV at WOT. I am hoping to get it in the 850 range, but I don't know if its possible. My fuel trim is rich across the board. I think I may need to get an adjustable fuel pressure regulator for my tbi unit. Anyway, after redlining it, I got 7PSI, which is about right. But why would the kit claim 12 if the max I could ever get was 7?

Sean:
If your O2 readings at WOT are 850 mv, this means that you are running too rich...remember : up from 450 mv you have a rich condition, down from 450 mv you have a lean condition.
Are you using the FMU kit that came with the system?
Is your fuel injection system is the speed density type? If so you might have a problem on the MAP sensor, because the one you are using does not tolerate pressure only vacuum, this can cause the system to go the very rich condition, to avoid this situation you will need to use a vacuum check to avoid pressure going to the MAP sensor under boost condition.
But, this could cause most other problems for tunning your engine, I suggest that you change your fuel injection system to the HOT WIRE air flow sensor type , this could cure most of the problems.
But also you can burn a chip to your PCM to have the same results.
Well, meanwhile keep it safe , and run you engine a little bit on the rich side.
Take care.
Enjoy the boost.
Pablo
ps: did you liked the videos I posted?

[stuckatcuse]

Actually I was hoping to have about 750mV, but even with the FMU leaned out all the way, it's still too rich. The computer is set to go to enrichment mode near atmospheric pressure. Then the FMU takes over. Only problem is that I think my base fuel pressure is a little high. I might re-do my TBI unit and put in an adjustable fuel-pressure regulator. I think that should help my rich problems. In the mean-time i'm up to 7psi, which is the stated boost of the low power kit. I think I may have the wrong pulley. I'm going to pop my belt off and measure it later today.
Thanks for the suggestions. I need to get my fuel pressure gauge up and running!

My long-term plans are to use bigger injectors, keep the stock fuel pressure, ditch the FMU and get a 3bar MAP.
Then I can do custom tuning and the computer can see boost up to 25 PSI
Sean

[pablo]

Actually I was hoping to have about 750mV, but even with the FMU leaned out all the way, it's still too rich. The computer is set to go to enrichment mode near atmospheric pressure. Then the FMU takes over. Only problem is that I think my base fuel pressure is a little high. I might re-do my TBI unit and put in an adjustable fuel-pressure regulator. I think that should help my rich problems. In the mean-time i'm up to 7psi, which is the stated boost of the low power kit. I think I may have the wrong pulley. I'm going to pop my belt off and measure it later today.
Thanks for the suggestions. I need to get my fuel pressure gauge up and running!

My long-term plans are to use bigger injectors, keep the stock fuel pressure, ditch the FMU and get a 3bar MAP.
Then I can do custom tuning and the computer can see boost up to 25 PSI
Sean

Dear Sean:
Are you using the procharger FMU? because this FMU is designed for MULTIPORT FUEL INJECTIONS..NOT TBI.
Fuel pressure at idle for your engine is: 13 to 16 psi, and under 7 psi of bost your fuel pressure must go up to 25 psi.
When you say: you lean out the FMU, you turn the adjusting knob all the way to the left...do you?
In my humble opinion you should keep the injectors, ditch the FMU and get one that works for loww pressure systems as yours, but I do agree to get a better MAP sensor.
take care.
pablo

[stuckatcuse]

Thet FMU I have came with the TBI kit. I was designed to give 25 PSI a 7 lbs of boost (according to the instructions). I measured my pulley at it's definitely a 2.55" unit. I guess I should get my fuel pressure problems sorted out first, Then deal with my lack of boost. I'll keep you guys updated. I should be getting my fuel pressure gauge in early next week.

[stuckatcuse]

Well I seem to have my fuel pressure problem ironed out. However, I still can't get above 6 or so psi?? What gives? I must have a boost leak?

[pablo]

I need to know the size of the crankshaft pulley...to figure total RPM of the supercharger.
Please post the size and I will let you know exactly how much boost to expect.
Pablo.

[stuckatcuse]

I need to know the size of the crankshaft pulley...to figure total RPM of the supercharger.
Please post the size and I will let you know exactly how much boost to expect.
Pablo.

I think I may have found the problem. My idling (base) fuel pressure went up to 18-19 psi with the ATI FMU installed. When I take it out It returns to where it should be (13.5 PSI). I think It's related to my low RPM sluggishness when I floor it, as well as my lack of boost. My block learns are all about 25% rich except at High RPM under boost, where high fuel pressure is necessary ( the FMU increases fuel pressure with boost as it should) I called ATI and talked to ERIC. He had no idea why an otherwise normally functioning FMU would raise the base fuel pressure like this.

Anyone have any ideas?

Sean