Recently I relocated my MR gauges to the A pillar. I had to add about 4 feet of vacuum line to the original gauge. I didn't see any way to calibrate the gauge but it is reading way below normal. Does the length of hose affect vacuum/pressure readings? The only reason I kept the stock MR gauges up to this point is because I bought an avic d3 (which is still sitting in the garage waiting for the orbital double din V2 - but that another thread all together ) and have to wait to get the Defi red racer gauges i want (so expensive! ). Is this error in the readings going to be with me until i replace the gauge with a better one?

 

No, but maybe your splice is leaking. The stock gauge line has a restrictor T where it connects to the manifold to protect the gauge I guess. I ran into a problem with my aftermarket gauge but not my stock one.

Before you start your car is it on Zero?

Once you start your car how much vacuum does it read?

What does it read at full boost?

 

When the car is off the gauge reads 0. But when I start it at idle iit reads 50 cm/hg of vacuum which is about 20 in/hg. Full boost reads .7 bars; about 12psi. Totally abnormal. I'll check the line for a leak, but i haven't touched the original line, simply added line.

 

I just noticed the restrictor in my line today and yanked it out.. The stock gauge was very sluggish with it in.. Would this cause any problems with leaning out, etc? Maybe I will log a few runs with the wideband to verify.