Speed Pro MAP Question

[Jeff Rand]

O.K. I got my Speed Pro working well but I have noticed that my VDO boost gauge does not give me the same readout as the Speed Pro. I have recently changed the 3 bar map and my pickup for the VDO is on a separate line (the line that use to supply vaccum to the EGR valve). The gauge reads 17# and the data logger is showing 14#. Should I have a "T" off the MAP line for the boost gauge?
Thanks,
Jeff

 

[NoSlix]

Jeff,

Unless you spend big bucks($100's of dollars) on an industrial calibrated pressure gauge, you're likely to see this. Most of the automotive gauges we buy from Autometer, VDO, HKS etc have a +/- variance of about 3-5psi. We tested a bunch of gauges once against a calibrated gauge( +/- .25 psi at 100psi). The Autometer and VDO were wayyy off. The HKS was closest at 28 psi. Within 1psi. I also tested three 3 bar MAP sensors. All three were almost dead on to what my calibrated gauge showed at 28psi. I'd go by the MAP sensor. Hope this helps.

 

[Jeff Rand]

Thanks Shane for the information. Lets see, if I go by the MAP then I have some untapped horsepower available. I will still stay on the conservative side anyway.
Jeff