45 psi??

[pdzz]

I'm running a classic FAST. Had it at T&T on Friday night, trying out my new turbo and waste-gate(PW-46mm). During my second run, I looked at my boost gauge, it was reading 30psi!! Well by the time I noticed, there was a cloud of smoke.. so I lifted about the 1,000ft mark and coast to a 10.48. Pushed out a head gasket.. Here is my question.. On my data log I see the MAP is at 312kpa, which converts to 45psi!!! Is it possible for the FAST to see 312kpa, with only a 3bar MAP?? I'm trying to figure out what happened, whether it was the AMS or the new waste-gate.. Phil.

 

[norbs]

Well not exactly, the scale reads a bit different. Normal atmospheric pressure is 100kpa approx. So the sensor reads about 100. kpa when the key is on. If you had 200kpa on the scale you would be at 14.7 psi approx in the motor. So 300 kpa is 29.4 psi approx. However the scale stops at 314 kpa and you could of had maybe 40 psi in the motor becuase it actually stops reading at 30 psi. So you boost level is unknown...it could have been 50 psi even with a blocked gate!

 

[pdzz]

Thanks Norbs, I forgot about barometric psi. I will tell you this, is was pulling like a freight train!! I'm sure I was on a nine second run before i lifted... Well, off come the heads! BTW, no knock retard at all! Phil.

 

[norbs]

Your using an ams500 or 1000? How did you have it setup?

 

[pdzz]

AMS1000. Had it set for one stage,using CO2. 30psi against the gate with a 7lb spring. Was hoping for 25lbs of boost. First run was a waste do to the fact that I didn't arm it before I left. Need to get it on a dyno to figure it out, or more seat time. Phil.

 

[norbs]

I arm mine with a 5 psi hobbs switch. It really holds the boost steady within about .5 psi, on my car. It should have worked for you if you set the boost on it to 17 psi approx. you need to baseline the 7 psi with the ams off.

 

[pdzz]

Well, got the intake off... Found a couple of burn holes in the head!! Yikes!! I'll have it off soon, post some pics. Hopefully it can be repaired. Phil.

 

[Mike Licht]

cometic gaskets?

 

[pdzz]

GM shims. I'm pulling the head tonight, hopefully it can be fixed. I have alot of port work done to them. Phil.

 

[norbs]

The one thing that I did like about my Gen 7 was that it had a feature that would cut off each cylinder if the boost exceeded a preset set point vs rpm. Nice feature too bad the rest of the software was lame. Hope you can save the heads.


norb

 

[KevinB]

The one thing that I did like about my Gen 7 was that it had a feature that would cut off each cylinder if the boost exceeded a preset set point vs rpm. Nice feature too bad the rest of the software was lame. Hope you can save the heads.


norb

I wouldn't call it lame once you know how to use it.

 

[pdzz]

Already at the machine shop.. He say's he's fixed worse!!! Phil

 

[tsm3089]

?? so did you put 30 psi of co2 on the gate with a 7 psi spring.

 

[pdzz]

?? so did you put 30 psi of co2 on the gate with a 7 psi spring.

Something like that!!

 

[Otto J]

Something like that!!

In a perfect world with noe back pressure you are looking at 30+7, you do the math.

Always start low with an AMS. Basically figure you boost will be whatever pressure plus spring until you hit backpressure with the turbo.
IE... 7PSI spring + 15PSI co2 = 22#s.