shiper

I've got problems and need to see what boost the my95 wagon is running at .
I've just received my gauge from scoobyparts and there are no istructions on where to conect the pipe to the turbo???
Also it is in LB/sq" and not sure how much my car show read. It has a s/s from turbo back with no cat an upgrade on the panel filter otherwise no more mods.

Fuzz

you have a couple choices really, this one will tell you what boost the engine is actually getting, true(er) reading.
my choice personally.



This position will tell you what the turbo is actually putting out boost wise and will be higher than the first position (due to losses through intercooler etc)



Hope that helps
Andy

shiper

Cheers Andy for that.
I also dont know what the boost should be in lb/sq" and if you can adjust it?

dhorwich

On a MY95 car you are best off taking it from here see bellow:

I took mine from the middle of the 3 pipes which are found on the top of the inlet manifold, just in front of the intercooler and behind the alternator...



Dan

Fuzz

14 psi is standard is'nt it
can someone else confirm tho please

shiper

I've fitted it now and the needle goes down to -9LB/sq" and moves up and down when i rev it. I'm now very concerned that my turbo's knacked.
Please help.......

dhorwich

That is normal....

The turbo will register negative on the gauge beacause there is no positive boost at idle or when you release the throttle, i.e no air is being pushed into the engine, when you are getting negative pressure on the gauge it means thats the engine is sucking air in as the turbo is not on boost....

Im not sure what positive pressure the UK car runs must be something like 0.8bar+ may be more..???

Dan



[Edited by dhorwich - 8/25/2002 11:55:26 AM]

[Edited by dhorwich - 8/25/2002 11:56:24 AM]

Fuzz

He wants it in Lb/sq" or Psi as I stated already but wasn't confident if it was correct

14.7 Psi is = to 1 Bar by the way...I think, oh my brain isn't in gear yet

shiper

Thank you all for your positive, very helpfull input.
Cheers m8's

tweenierob

Shiper, what positive pressure are you getting on boost??
-9 is ok on tickover but what about when accelerating?? are you getting -9 on acceleration??
Rob

Pavlo

I get the equivalent of -.6 bar at idle. Goes up when you open the throttle.

Beware the pressure gauge probably reads 0 to -30 inches of water in the vacuum region, so do check.

PLEASE NOTE!
If you put your boost gauge on the manifold (which is correct) you will read a greater vacuum that if you put it direct to the turbo (incorrect position, do not put it on pipe from the turbo!).

The ecu reads pressure from the manifold, and will adjust the boost according to what it measures here. There is also a pressure drop between the turbo exit and the manifold.

edited to add: I notice fuzz did explain the two points!

You can also remove the square drive threaded plug threaded into the manifold, as seen on the extreme left of one of the pictures. I used the hole to fit the 1/8 NPT fitting supplied with my Autometer gauge, no tees neccessary

P

[Edited by Pavlo - 8/25/2002 8:49:18 PM]

dhorwich

I thought it was strange 'Teeing' into the hose from the turbo...!!

pavlo, you seem to know your stuff, not just on this subject..

Dan

Pavlo

when you have made as many mistakes as I have, and followed blindly into the arena of failure as many times as I have, you begin to learn something!

P

dhorwich

CataIunya

What timing I was gonn ask a similar question as I just bought a boost gauge. I just tucked me cubs in though and went for the spare nipple on the manifold like already mentioned. I read high minuses until i blip the throttle, dont get high pressure 14 psi until 3rd or 4th is that right ?

shiper

Took it for a spin and the boost goes upto 14psi sometimes but seems to settle to @11.5 most of the time on hard acceleration.

Pavlo

Catalunya,

What you are seeing seems about right. When idling the engine is still sucking hard, but you have closed the only air intake (throttle butterfly) so it pulls a high vacuum. When you open throttle to rev, air rushes in, vacuum drops.

Paul