Greddy Mechanical Boost Gauge

[Just_Rb]

Ive recently purchased a mechanical boost gauge for my r33 gtst and have wired it all up and pulled the vacuum hose through into the engine bay and after reading some previous posts (without pics) i am unsure of the best place to tap into the line for the y piece, should it be at the front of the manifold or at the rear? some people say one thing others say another could i get your professional thoughts as to where to tap the y into for the most accuracy.

[mad082]

most people go spot 2, because it is closest to the firewall and a bit less obvious.

neither of these will give you the most accurate reading though. they will give you an accurate reading of how much boost the engine is getting, but not what the turbo is actually doing. to get an accurate reading of how much boost the turbo is producing you need it reading from before the intercooler, however this will not give you a vaccum reading like having it from the plenum will.

[Just_Rb]

thx so tapping into the rear of the manifold is better ? or is it just a matter of convenience?

[Dose Pipe Sutututu]

Convenience, you'll still get the same plenum pressure readout

[Just_Rb]

bump

[Dose Pipe Sutututu]

bump

I don't know why you need to bump it, you just got 2 answers and they're both the same.. it doesn't matter either 1 or 2 because with you both, you will read +ve and -ve pressure of the plenum. Just don't be a tool and mount it pre throttle body like some.

[adzR34]

Well id hesitate to tap it off the FPR as mechanical gauges intrudce latency issues. Ideally it should have a short genuine line from the plenum keeping it responsive to intake variations. The best place to throw a mech gauge i believe is to a vac line that doesnt have critical components feeding from it.

I too have that exact gauge, have fed the vac line through but have been lazy in conecting it. So where have the others connected it to?

I don't know why you need to bump it, you just got 2 answers and they're both the same.. it doesn't matter either 1 or 2 because with you both, you will read +ve and -ve pressure of the plenum. Just don't be a tool and mount it pre throttle body like some.

[Dose Pipe Sutututu]

Makes no difference, you won't even notice the difference!

if you don't believe me, connect to Boost Gauges and test it yourself

[adzR34]

Funny you say that, the first night i plumbed it up i went for a few runs and i had the engine light come on. That was plumbed to the vac line from plenum to boost sensor?(R34) I have since pulled it out and no real issues since. Im assuming by taping that vac line it would be getting a lower reading than actual. Hence why id like to find out what others have done.

Someone a while ago said the FPR is not a good idea....

Cheers

Makes no difference, you won't even notice the difference!

if you don't believe me, connect to Boost Gauges and test it yourself

[Just_Rb]

thanks for your input guys but due to the mixed opinions it still leaves me thinking where to tap it into???