vaccuum issues!!!!!!!!!!!!!!!

**lancesT/A** · 03-29-2010, 06:50 PM

Ok here is my set up 408 lq9, stage 3 243 heads, cam is a 248/254 .618/.622 113lsa, fast 92/92. 42lb injectors. i have almost no vaccuum. the car is a yr long project and a rather expensive one..... if anyone has any hints as to why i have very little vaccuum let me know cuz im scratching my head

**Cutlass** · 03-29-2010, 07:28 PM

because your camshaft is huge

**lancesT/A** · 03-29-2010, 08:02 PM

ya but plenty ppl run bigger well what do i do to get vaccuum up??

**mark21742** · 03-30-2010, 12:08 AM

Vacuum pump or ditch the booster and go manual brakes...I take it that's why you need more vacuum.
Yes your cam is why you don't have any vacuum

**lancesT/A** · 03-30-2010, 12:30 AM

even at idle i would think i would atleast at idle.. no?

**mark21742** · 03-30-2010, 08:58 AM

Nope

**shady milkman** · 03-30-2010, 11:35 AM

Originally Posted by lancesT/A

even at idle i would think i would atleast at idle.. no?

Originally Posted by mark21742

Nope

i love the straight to the point

i would personally lance (i hope that is your name) run a booster to keep with the dive-ability of the car

**bigrondownhiller** · 03-30-2010, 03:26 PM

You could also go with a hydro boost for the brakes.

**lancesT/A** · 03-30-2010, 03:32 PM

ya well right now it wont idle and once u get above 3500 rpms it acts fine i know the cam is robbing some vaccuum but im not sure its not losing it thru the intake im gonna put a stock one on and see if i hold vaccuum

**bigrondownhiller** · 03-30-2010, 04:13 PM

Sounds like you have a vacuum leak somewhere.

**cammed goat** · 03-30-2010, 04:22 PM

Originally Posted by Cutlass

because your camshaft is huge

**cammed goat** · 03-30-2010, 04:23 PM

I have read in GMHTP that a vacuum booster would be required for vehicles running large cams.

**Cutlass** · 03-30-2010, 06:16 PM

To get a big cam to idle better, sometimes you need to crank the ignition timing way up.

**lancesT/A** · 03-30-2010, 06:26 PM

i have to mention the advancing the timing to my tuner

**mark21742** · 03-30-2010, 07:00 PM

Originally Posted by lancesT/A

i have to mention the advancing the timing to my tuner

I ended up adding about 5 degrees advance to my idle timing to get mine to smooth out and drop. 238/242 idles pretty smooth at 990 rpms and will probly be dropping down alittle more after i'm finished all the other tuning