Forgive me guys but I'm a newbie at reading the gauge. I'm getting about 11 in HG Vacuum on the meter and I've got the 3.33" pulley. Is that correct or am I leaking somewhere? I managed to hook up the boost gauge but I put a kink in the clear plastic line that runs into the t-fitting on the vacuum hose. Should I replace that plastic line?

 

I think that's low. I get 20mmHg and I too have a 3.33 pulley.

 

Pulley size shouldn't affect your idle vacuum... The BOV is fully open bleeding the boost to atmosphere...

 

My Autometer gauge is measuring in inHg. What gauge do you have?

 

sorry, typo....should be in Hg.

I have Apexi mechanical boost gauge.

 

Wow...looks like I've a big leak somewhere...

 

Or that kink in the nylon hose is messing up your readings, i had that problem too. I bought a tiny piece of cooper tubing to run instead of that nylon stuff.

 

Dude lemme know if you find out the cause/fix. I have the same exact problem on mines. Haven't been able to find any leaks. Everything is running fine..

-D

 

Update:
I swapped out the kinked tubing with new nylon tubing. I'm at 15/16 in HG. That means I'm still leaking. I'll have to see where I can find some copper tubing.

 

I had a leak for a long time.

Turned out that it was both the gauge leaking where it met the tubing, and a leak at the EGR tube at the back of the manifold.

I found it by going to a shop with a "SMOKE-IT" machine. They pump harmless white smoke through the system - wherever it comes out - there's your leak.

Took them all of 5 minutes to find it - I had been spraying brake cleaner over my vacuuml ines for months before that.

I now read 19-22Hg. It seems to vary a little by outside humidity and temp - it's usually at 19 however.

Now I'm still trying to figure out why I only read 7.5PSI of boost with a 3.12" Pulley.

IanS

 

Thanks Ian,
I've always suspected that it could the tubing setup because it didn't feel that snug at the connections. I'll look for the copper tubing and try that out instead.

 

I ended up just fabricating a connector going from the nylon tube to the back of the gauge using rubber hose.....

But in my case, the tube was fine, just the connector sucked.