I went to get my car tuned over the weekend, and my tuner noticed that my hydra isn't seeing boost correctly.. I checked the vaccuum line running to the unit and it is fine.. at 8psi guage pressure the hydra fluctuates between 3.5 and 4.7 psi? what gives? it is fine under vaccuum, but no where near accurate under boost.. is the internal map sensor shot? does anyone know where to get a replacement, other than the obvious calling Andrew at Hydra.. any help or suggestions would be great. Thanks

open the box IF IT DOESNT AFFECT WARRANTY

and notice how its made

the hose might be loose

alex

The Hydra reads in absolute pressure which tends to read about 2 psi less than most aftermarket boost gauges but some do also read in absolute. Given you are in Colorado I suspect elevation is a significant factor that your boost gauge isn't accounting for where the Hydra is. Given you show about a 3 psi difference sounds like it's functioning correctly.

but shouldn't the bosst be steady? according to the hydra it fluctuates alot.. and the according to the guage it is rock steady.. also when I crimp the line running to the hydra shouldn't it stall or rev the engine?? when I clamp the hose the vaccuum reading on the hydra doesn't change, and the motor doesn't react at all.

No boost gauges are highly damped so they don't flutter. The internal map sensor will pick up your valves opening and closing.

Clamping the line boost/vacuum line isn't something I would recommend you can see everything you need to see within the software. All this will do is have the Hydra reading 0 and it's not likely going to do much more than run richer.

so should my tuner go by the map sensors readings? he was sceptical doing that because there was such a huge variation. and its readings were jumping around so much. he has runed on Hydra before and said that he didn't think it was normal.

Mine does it too its normal just tune with the hydra readings not your boost gauge

I don't mean to beat a dead horse, I am just nervous about tuning like this.. so if I want to tune for 28 psi, my current situation would have about 36psi on the guage, and the hydra would fluctuate between 28-26 psi.. give or take.. is this correct.. I am assuming this is ok so long as a/f, and timing are ewithin a safe area.. let me know. Thanks again for the replies you have been a alot of help.

also phil,
If I clamp the line shouldn't the hydra read 0psi-hg? it stays at -588 at idle and doesn't move.

also phil,
If I clamp the line shouldn't the hydra read 0psi-hg? it stays at -588 at idle and doesn't move.
Try disconnecting the line/tee from the manifold instead of clamping the line.

Try disconnecting the line/tee from the manifold instead of clamping the line.

Correct, if you clamp the line while the car is running it will hold vaccum as it's an air tight sensor.

Thanks,
Phil
www.elementtuning.com