Boost leak??..some help

[mccurdy]

Hey all,

I got a 30-0-30 apex boost guage in my car along with a 19C turbo (ported/clipped). and i notice at idle the vacuum reads at around 17-19'ish. the wierd part is when i like give it a little gas , then let off in neutral, the vacuum reading will dip into around 25 then go back to about 18 after like 2 seconds. What could this mean?

Its like i give it any gas in neutral, and let the boost hit 0 and it'll drop down to 25 vacuum then rise back to around 18'ish. Is this a leak somewhere? Whats the average vacuum at idle?

Also: I dont reach full boost till around 4,500rpm's. major lag. its now worse with my downpipe on. and if i like give it gas and slowly accelerate my boost reading seems to slowly drop down to the vacuum readings. Its a slow drop but its there. Any ideas??

Oh yeah, i got a 3'' donwpipe cat eliminator with a hole in the flex section if that makes any difference.

 

[Defiant]

Originally posted by mccurdy
Hey all,

I got a 30-0-30 apex boost guage in my car along with a 19C turbo (ported/clipped). and i notice at idle the vacuum reads at around 17-19'ish. the wierd part is when i like give it a little gas , then let off in neutral, the vacuum reading will dip into around 25 then go back to about 18 after like 2 seconds. What could this mean?

It means your pistons are moving faster, and drawing harder against the throttle plate. Stock idle's supposed to be around 18-20, so you're not far off if at all. However, because of where your vac gauge is mounted, it won't show a boost leak- it's only sensing inside the plenum, unaffected by leaks. You need to pressure-test the intake tract from the blower intake to the throttle plate to find boost leaks.

 

[mccurdy]

ok...it jsut seems i dont start building boost till the rpm point where i SHOULD be at full boost ie 3,300 rpm's....somethings majorly wrong...ARRRGGGHHHHH HELP!!@#@!

 

[1fast97gsx]

the hole in the flex section makes a big difference .. mine was cracked and once I fixed it I noticed gains.

 

[mccurdy]

but its just like running open exhaust...why would that be bad? Should be good if anything.....

where can i pick up 2.5'' rubber tubing/hose to build the vfaq leak tester?????

 

[IHeartTurbo]

Originally posted by mccurdy
but its just like running open exhaust...why would that be bad? Should be good if anything.....

where can i pick up 2.5'' rubber tubing/hose to build the vfaq leak tester?????

at any parts store...all you need is radiator hose. i got mine at a tractor dealership i worked at.