I have a BG CUSTOM TURBO Turbo kit with a PT 76GTS turbo, the downpipe is 3.5" all the way to a bullet 3.5" muffler under the passenger seat.

@ 6700 rpms in 2nd it shows 26.1 psi after the A2A Intercooler and back pressure reads 46 psi.

@ 6200 in 3rd threw the traps, 26.psi boost. Back pressure shows 42 psi.

Next time out, I'm going to log boost pressure before the intercooler to see how much the intercooler is backing up.

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Is this with a .81 AR or a .96 AR turbine housing ?

David

 

What are you using to log that information ?

Gary

 

It's the .96 housing

I tap'd the header right near the turbo flange, ran copper tubing to a 0-100 sensor (used an AEM sensor 30-2131-100 since it was $58 vs $145 for the FAST one). Then setup the FAST XFI to log that sensor.

 

When you hook up the pressure sensor are you using 5 volts or 12 volts? The Fast help seems confusing with this.

 

The AEM sensor uses a 5v power, so I used Pin J of the Analog connector to feed the sensor the 5v. The Fast sensor (307062) is a 12v power, according to the Fast instructions you would just hook up a +12v switched power to it. Not sure why they wouldn't just use a sensor that is 5v also.

 

Thanks for the info. I thought maybe I was reading it wrong.

 

What throttle body and whats your psi in the intake?

 

70mm Accufab TB, and the boost in the datalog is from the intake. Going to check the pre-intercooler boost numbers tonight.

 

Good info

 

Actually looks like bad info. The FAST XFI MAP is showing 26.1 psi, but I tried to log pre-intercooler psi tonight and the AEM sensor only showed 19 psi. So I watched the Eboost2 through the traps and it shows 19 psi. So for some reason the FAST map is reading high.

So backpressure might be sky high.....

 

Still good info, you just need more to sure which is more accurate.

Always need more...

 

Wow, keep us updated on the corrected numbers

 

2:1 is considered normal.

 

2:1 yes, but if the 19 psi is correct. Thats 2.42:1, is that ok still?


I just checked both the AEM and the 3bar MAP. I used a small air compressor with a Regulator. I tried them @ 10, 20, and 30 psi (Actually took the AEM also up to 40 psi). And they both read the same amount of pressure! So how can the 3bar which is off the side of the upper intake read 26 psi on the track, and the AEM only read 19 psi right off the Turbo compressor???

 

I have never heard that before. I thought that was borderline ok at best.

 

Anything under 2:1 is pretty darn low . Most street setups that are for torque and quick spool are well over 2:1.

 

I am checking my back pressure in the spring and if it is close to 2:1 I will ditch my tailpipes and run bull horns.

 

That is strange. Maybe the intake sensor is in a high ram air pressure area of the intake and maybe the compressor fitting has so much velocity rushing past it that it acts as a venturi and lowers the reading? IDK its a long shot but if they both read the same otherwise it would make sense. That or try heating up the intake sensor/wiring with a heat gun and see if it changes.

 

I was thinking that the sensor wiring might not be making a great connection.

Maybe test the resistance of the signal wires and then double check pressures with a
mechanical gauge if at all possible.