20" of vaccum at idle????

[veedubin]

well i finally got an aftermarket boost/vac gauge and put it in yesterday....... according to the gauge i'm at 20" vaccum at idle i can get it to about 28" if i snap off the throttle while cruising. I was thinking these cars should be running around 15" or so am i wrong. Also the other thought i am having, i think my new gauge might not be completely accurate..... my stock boost gauge peaks under full accel at around 7psi +/- .5psi the aftermarket ( a Faze BTW) only peaks at 5 which to believe???? Oh, not to make this any longer than needed, but i have one other concern (as this is my first dealings with a turbo vehicle) should it take running through first gear at full throttle to finally get boost as soon as i pop into 2nd??????? thanks guys

 

[mkIIIman089]

It can take that long to build full boost, 1st is just very quick and has relatively low load conditions.

Vacuum sounds healthy to me as long as its not bouncing around in any weird fashion.

Which gauge to believe... well neither are very good... but I would hope the Faze would be more accurate.

 

[lagged]

buy a repair manual so you can avoid having to ask questions like this.

 

[bountykilla0118]

"You can never have to much vac" .....

 

[starscream5000]

20 in/hg vacuum is good, 21-25 in/hg is better .

 

[Supracentral]

Read this:

http://www.supramania.com/forums/showpost.php?p=249145&postcount=6

 

[Ric]

my 1jz is a steady 15in/hg vac at idle.. My ex cam is retarded 2.5 degrees.

 

[mhopemk3]

Mine runs about 18.. Good link there supracentral.. BTW I've seen someones sig with all the gun pics and realized you are the only one without your finger on the trigger.. :thumbup:

 

[lagged]

my 1jz is a steady 15in/hg vac at idle.. My ex cam is retarded 2.5 degrees.

not relevant. this is the 7m section.

 

[Supracentral]

not relevant. this is the 7m section.

Vac rules rules hold true for just about all 4 stroke gasoline engines, regardless of manufacturer or configuration.

It's relevant.

Now why you would run your cams like that is another question entirely...

 

[Ric]

Vac rules rules hold true for just about all 4 stroke gasoline engines, regardless of manufacturer or configuration.

It's relevant.

Now why you would run your cams like that is another question entirely...

It's a stock cam 1jz trick figured out by our boys down under years ago. Dyno's good for around 10 peak hp and 20+hp under the curve with a flatter and longer powerband. On a stock boost car, it feels like you raised the boost by 4 pounds.

 

[lagged]

Vac rules rules hold true for just about all 4 stroke gasoline engines, regardless of manufacturer or configuration.

It's relevant.

Now why you would run your cams like that is another question entirely...

then i stand corrected.

 

[Nick M]

Read this:

http://www.supramania.com/forums/showpost.php?p=249145&postcount=6

Yep.