5 GT Turbo Typical Vacuum During Cranking

[Woznaldo]

This is probably one for the EFI crowd, but obviously if you know, don't be shy.

I'm currently cranking and with a local pressure of 90 mbar, it drops to 80 mbar during cranking, so 10 kPa of vacuum or 1.45 psi??

I know std C1J only run 7.9:1 CR, but that seems low to me? I am running a Cat Cams 325 Cam, but that shouldn't have a significant impact?

What the typical vacuum on a C1J during cranking?

edit: changed mBar to the correct units of kPa!

 

[Woznaldo]

Sorry, all units should be in kPa, not mbar.

 

[DaveL485]

Sounds about right mate, You wont see a lot of vacuum until it fires up and it starts to demand a lot of air. I can dig out a crank>start data log if you want numbers.

 

[Woznaldo]

Thanks Dave, just want to make sure nothing is amiss.

 

[DaveL485]

Highlighted the crank phase yellow, chart is Time in seconds on the x axis, and 0-100 on the y plotting MAP in KPa and RPM/100. You can see in the cranking phase the MAP value stays very high compared to the run phase.

 

[Woznaldo]

Perfect. Thanks Dave. Very much appreciated.