Guys

 

I've just fitted a Greddy boost guage - courtesy of Baz - and now I'm confused about what it's telling me.

 

If I'm just driving along the guage reads negative. If I'm on slight acceleration it may creep up to zero and if I really give it some then the guage will climb to 0.5 bar maximum but no more than that.

 

Is this right ? If the guage is giving me a negative reading unless under acceleration doesn't this mean that it's blocking the input tract ? I would have thought it would only ever read zero or above..... :confused: :confused:

 

Mark

No comment.......

I think you need to take your car to a garage....

 

While you're there, ask them how much they'll give you for it on a part ex and get yourself something you either:

 

A) Understand

 

or

 

B) Don't need to understand

 

;)

Oh and one more point, you're in safety boost ;)

your gauge should read negative whilst on idle, not exactly sure but I think it should read between -20 & -24, mine is about -20

 

I think I may have a bit of a vacum leak somewhere

Air comes into engine. It goes into cylinders. It goes out of exhaust. So that air has disappeared from the system - which means there is vacuum in the system - hence negative readings. At idle the turbos are doing nothing and the engine continually requires air, so there's a steady negative pressure. This vacuum sucks the new air through the intake and into the engine and so the cycle repeats...

 

The "boost" indicates whether or not you are further compressing the air before it goes into the cylinders, which means you can burn more fuel, which means more go - BUT the turbos will not compress air unless they specifically need to. If you are on part throttle there's enough "normal" air for the small amount of fuel you are injecting anyhow, so there's no point compressing the air - and in fact if you put too much air in for the amount of fuel you run lean and get det.

 

1/2 bar max means either you've got leaks or you're in safety boost - stock boost is 9psi which is .6 bar ish. (Bar = 14.7psi)

No comment.......

 

Not even a sarky one? You're going soft...

 

...ah, no you're not. :cool:

Zevans - thanks.

 

Andyduff - what a c*ck ! We're not all as clever as you. If I needed a childish comment I'd speak to my niece who's three and who at least would be trying to help.......

Zevans - thanks.

 

Andyduff - what a c*ck ! We're not all as clever as you. If I needed a childish comment I'd speak to my niece who's three and who at least would be trying to help.......

 

Have to agree Andy, the man is a subcribed member who has paid towards the club to get some help when needed, your comments are well out of place IMHO

LOL take your sense of humour back too

Duffman

 

I don't think your sense of humour goes down too well with some people...but who gives a sh*t- life's too short to be overly sensitive. I saw the funny side anyway, lol.

 

Mark

 

Duffman DID give you the advice... after some ribbing. You did go through the trouble of fitting a boost gauge without understanding what it is for, hence Duffman's natural response. I would have taken the piss too if I had read it first, :-).

 

You have to read replies more carefully!

 

Duffman's first reply would have been nasty had he not followed with the following two. The end of the second showed a smilie face meaning that he's KIDDING! The third IS the advice ie you are running in safety boost.

 

My advice would be to search on this forum for safety boost. You'll find loads on info mate, LOL. I had it sometime ago. However, it does return every now and again though.

 

Van

Mark, let me introduce you to Andy....oh...I see I'm too late....oh well...

 

Anyway, as advised already, safety boost can be caused by several diff probs, do searches and go through each possible cause 1 by 1, thus reaching the problem point....

 

Theres also a 300zx online manual but I dont have the link anymore, can someone paste it on here for Mark please......it'll come in really handy for locating parts on the Zed to diagnose..

 

Good luck mate....

Call it an apology :) LOL

 

http://www.300zx.co.uk/cgi-bin/manual.cgi

Mark,

 

Have you tested again once your car has warmed up. It may just be that the car is cold and is still in saftey boost.

 

Once warm you should have about -20 at idle and around 9 -10psi at full shout.

Rather than use a turbo timer it's good to use the gauge to not go into boost (i.e. posative psi - if you can help it) for the last couple of miles of your journey.

Thanks everyone - Andy too.

 

Mark