I was wondering if my vacuum reading at idle looked good. My idle is a bit high at 1,100 RPMS and my boost gauge shows 400mmHg. When the idle drops down to 900 RPMS is shows like 390mmHg.

My engine has 105k miles on it and has the following mods: TB Mod, EGR & ACV removed with block off plates, Bonez DP, FCD, and an intake filter. The stock TID has a small crack in it but I will be doing the TID mod in a day or two.

Are my vac. readings good?

 

get a reading with a steady 750 idle... then we can tell you.

is that with the stock gauge??

 

Probably.

 

This is with a Greddy boost gauge. I'll try setting the idle tomorrow and post what the gauge reads.

Whats considered good and whats considered bad (x# - x# is good and x# - x# is bad)? Thanks

Also, would a stock TID with cracks cause the vacuum reading to be low?

 

well 400 is 15". which is avg for idle. but it might go lower once it drops to 750. TID fix will probably make it go higher.

 

on these nice cold days I see -16 vac and it goes to -18 when I stick it in first gear, why is that?

 

Thanks scott. Hopefully my BOV will come in tomorrow and I can install it along with the TID mod. I'll try fixing the idle and post my vacuum numbers. Thanks!

 

I got my idle down to a little below 800rpms. The vacuum reading shows about 325mmhg. Should I be worried? I have my gauge hooked up to the fuel pressure regulator (if this helps).

 

I get like 12-14 psi with my street port @ 900 rpms.

 

bump

 

to le top...

 

that's only 12.8", really low for stock ports. check for vacum leaks. should be 15-20 could also be a weak engine.

 

rotarys naturally idles higher with intake and exhaust