It seems 90% of folks run their mechanical boost gauges off of the FPR vacuum hose on the passenger side of the engine bay with very accurate results. I intially installed my boost gauge here:



I didn't want to run the risk of it coming off the FPR, this is why I picked this location like a few other forum members. I felt like it's was pretty darn accurate but wanted to conclude it was just as accurate as the FPR spot, so I switched today to the vaccum hose on the FPR. Obviously bored at lunch

What do you know? Identical results and reaction...ie. vacuum was about 18psi at idle on both locations and boost registered identical, roughly 19psi peaking to 21psi during 3rd and 4th gear pulls...right where I have it set with my MBC. Needless to say I've concluded both locations are equal with the vacuum hose on the driver-side intake manifold being a safer option and will be swithing back tonight.

Hope this helps for anyone else on the fence about which location to tap into. This is more or less for folks who don't want it on the FPR, but want an accurate boost source too.

Orignal pictures are from JohnEB's thread...thanks for the good write-up!
https://www.evolutionm.net/forums/sh...ight=Boost+tap

 

thanks for the info

 

Nice, thanks for the write up!

 

without any leaks, they should be the same.

I personally run off the FPR. With decent fittings (barbed or flared) and decent hose, the most likely place the FPR line will come off is at the FPR itself (it's just a smooth pipe, no barbs or flares). Not the tap for the boost gauge. Adding a tap for a boost gauge won't increase the likelihood of it coming off if done right.

As a safety note, who doesn't look at their boost gauge almost daily? If the hose comes off the FPR, and that's where you have your boost gauge tapped into, you'll have instant notification something is amiss.

 

Like I said in the other post, what are the chances that would actually happpen? Very slim, which is why Mitsu puts it there (FPR). But to each his own.

 

Only reason I shared this is some folks are still skeptical about using the FPR. This simply gives them a proven alternative. Hope this helps for folks on the fence about location. In the end, either one is a great boost source.

 

Just dug this up but it's good to know both are viable sources for boost readings. I'm still on the FPR line and with a barbed T and zipties I'm pretty confident I won't lose a line...hope I didn't just jinx myself !

 

This thread should be locked. It is stupid. Any port in the intake manifold will have the same results. They all go to the same place.

 

Not locked but moved to right forum. Information is information. Choice is up to the user on using it.

 

What a dbag comment! Most of us all know this now, but some don't. The point made was that the FPR tap can potentially be dangerous if you have a failure on one of the lines. This thread just warns people to use zipties, keep on eye on all your boost lines and that you can pick another location for the source.

 

I picked up my EVO dirt cheap with a blown engine. After tearing into it, the cause of the destruction was traced to a boost gauge that was tapped into the FPR line. The previous owner had apparently removed the gauges when he sold the car (to the person I bought it from). Pretty much the first time he went WOT with it, it went BOOM. I've said it for years on DSM forums, and I'll say it again here. Never, ever tap the FPR line for anything. It's just not worth the risk.

 

The factory taps the FPR line for the OEM gauges.