I have the Defi BF series oil pressure gauge, now I read on http://www.42draftdesigns.com that the thread pitch is 1/8" BSPT...and I see people linking this piece http://www.42draftdesigns.com/product/42902.htm when they install their Defi gauges. So do I order this one (http://www.42draftdesigns.com/product/42902.htm) and tell them I need the 1/8" BSPT pitch or am I supposed to be ordering another piece?

I am going to tap down by the filter so I need an adaptor no matter what, but I'm confused which adaptor I need for the Defi bf series.

 

the adapter you have linked is the correct one you need for the Defi gauge.

 

What I don't get is why it says the Defi gauges are 1/8" BSPT but the fitting itself says its 1/8" NPT and also says "Our adaptor takes the place of the blank plug in the oil filter flange and allows the installation of an 1/8" NPT oil pressure sender." Am I just reading it wrong?

 

All pipe threads on the EVO and DSMs are BSPT, 1 thread per inch difference from NPT (27 vs 28 IIRC). If the defi guages are BSP, the adapter must be used just for the elbow. I've yet to install a sender in the EVO, but I've been dealing with this stuff for a long time between work and the DSMs. The 42DD page seems to make it pretty clear to me. Since they seem to have it all figured out, just ask for clarification when you call to order.

 

I e-mailed 42 draft designs and they told me I need this one if I'm using defi's: http://www.42draftdesigns.com/product/42921.htm but that doesn't have the elbow...