2nd gen fbody brake booster to ls1 intake manfold questions.
11-03-2008, 11:24 PM
#1
2nd gen fbody brake booster to ls1 intake manfold questions. I'm trying to hookup my 81z power brake booster to the LS1 intake manifold. I also have to "T" in my th350 vacuum modulator line as well. The factory booster uses a 3/8" line while the th350 line is ~3/16 and the LS1 intake port is much larger than the other two lines. How did you guys adapt these different size vacum lines?
11-04-2008, 10:13 AM
#2
For my Chevelle and its Brake Booster, I just used the OEM from the LS1 and made sure that the plug (check valve) was a good seal into the booster. I can't comment on the TH350 line as I have a T56.. but I would question if the Vacuum source should be straight manifold or ported vacuum?..
On the Back of the LS1 intake there should be a smaller port for the HVAC next to the MAP sensor.. you should be able to use a Tee or a Tee that has different sizes to connect up your Trans Vacuum line.
If you need ported vacuum, the vacuum port off of the front of driver side manifold (use for the HVAP) is better source (tho I don't think it is really ported vacuum), but is better at reacting for RPM Change and the Vacuum will drop and raise more than the rear ports (which seem to say steady and high vacuum).
Bottom line, just use some Tee's as needed....
On the Back of the LS1 intake there should be a smaller port for the HVAC next to the MAP sensor.. you should be able to use a Tee or a Tee that has different sizes to connect up your Trans Vacuum line.
If you need ported vacuum, the vacuum port off of the front of driver side manifold (use for the HVAP) is better source (tho I don't think it is really ported vacuum), but is better at reacting for RPM Change and the Vacuum will drop and raise more than the rear ports (which seem to say steady and high vacuum).
Bottom line, just use some Tee's as needed....
