Vacuum source location help
Thread Starter
Burning Brakes
Joined: Feb 2017
Posts: 942
Likes: 171
Vacuum source location help
I purchased a npp in a box kit from a member here for my LT1 base, it requires a vacuum source to operate. The instructions for LS3 engines is to break off a T tab on the back of the intake next to the fitting for the brake booster. My 2008 LS3 factory intake does not have this "T" tab but does have a large plastic protrusion that I can't clearly see, there's no way I'm going to try and snap it off. I need to locate a vacuum source, can't I just tap into the brake booster line? Any other idea's? Thanks
Thread Starter
Burning Brakes
Joined: Feb 2017
Posts: 942
Likes: 171
Race Director
Joined: Jul 2005
Posts: 12,021
Likes: 3,556
From: Central MO
I got the one for the LS3 since that's what I have. It's my understanding that the fittings are slightly different between the LS2 and LS3. Maybe you can contact the seller and see if they will send you the adapter part(s). From what I gathered from research, without actually seeing both adapters, it appears there is a "sleeve" arrangement on one of the hoses for the LS3.
Safety Car
Joined: May 2011
Posts: 3,807
Likes: 508
From: Oshawa, Ontario
this
I purchased a npp in a box kit from a member here for my LT1 base, it requires a vacuum source to operate. The instructions for LS3 engines is to break off a T tab on the back of the intake next to the fitting for the brake booster. My 2008 LS3 factory intake does not have this "T" tab but does have a large plastic protrusion that I can't clearly see, there's no way I'm going to try and snap it off. I need to locate a vacuum source, can't I just tap into the brake booster line? Any other idea's? Thanks
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Thread Starter
Burning Brakes
Joined: Feb 2017
Posts: 942
Likes: 171
I moved the coils to make more room, still can't get a good grip on the "T", my hands are large but not Mickey Mouse big. That damn tab blocking the vacuum port is in the way, need to try something else like snapping off that tab.
Instructor
Joined: Mar 2017
Posts: 226
Likes: 45
From: Lake Mathews Ca
I used a mirror and an Xacto knife to get back there and cut it off. PITA!
Burning Brakes
Joined: Oct 2015
Posts: 820
Likes: 332
From: Orlando Florida
I used a small open end wrench, 5/16" or 1/4", and using the braille method, reached back there and a slight twist it came off. I also used the braille method to push the vacuum hose on. I don't recall breaking the tab off, it's been a couple years since I added NPP.
Thread Starter
Burning Brakes
Joined: Feb 2017
Posts: 942
Likes: 171
So evidently I do have Mickey Mouse size hands because unless your a 15 year old contortionist getting your hands back behind the manifold is next to impossible. What I did was carefully use a Dremel to cut the tab blocking the vacuum port down to expose the "T" on the tip of the port, then used a long flat blade screw driver to knock off the 'T". I checked the port opening like member sphurley did with a pick and all was good. After all this the damn thing doesn't work. I have vacuum at the box mounted in the hatch well and followed the instructions but when I started the engine and pressed the fob nothing happened. I need to check the power source and dbl check the actuator lines but wtf!
Race Director
Joined: Jul 2005
Posts: 12,021
Likes: 3,556
From: Central MO
So evidently I do have Mickey Mouse size hands because unless your a 15 year old contortionist getting your hands back behind the manifold is next to impossible. What I did was carefully use a Dremel to cut the tab blocking the vacuum port down to expose the "T" on the tip of the port, then used a long flat blade screw driver to knock off the 'T". I checked the port opening like member sphurley did with a pick and all was good. After all this the damn thing doesn't work. I have vacuum at the box mounted in the hatch well and followed the instructions but when I started the engine and pressed the fob nothing happened. I need to check the power source and dbl check the actuator lines but wtf!
Last edited by BadAV; Sep 11, 2018 at 10:07 AM.
Thread Starter
Burning Brakes
Joined: Feb 2017
Posts: 942
Likes: 171
Thread Starter
Burning Brakes
Joined: Feb 2017
Posts: 942
Likes: 171
I did a dbl check of all connections and found that inside the control box the wires to the solenoid were not connected. The system is now working and I could not be happier with now having control of the exhaust volume.