My 6.0 is pulling vacuum on my TBSS intake, lookin for advice
 

Had my '03 dyno'd the other day. Tuner saw manifold pressure dip to 93 kpa. Thats with a 3" cai and a 90mm gold blade. He recommended running the holley hi ram. From the little I could find on a n/a 6.0 running this intake, it loses a lot down low.

I don't really want to port my intake. I'd like to take a shot at running a lsxrt. He said that it could be tuned, but that I really don't want to f*ck with it. I've also been looking at the pro-flo xt. Just looking for some input.

Mods are: AFR 225s, 230/236 .581/.581 114 comp cam, 1-3/4" LTs, full 3" single exhaust

Thanks for any help

How do you know it's coming from the TBSS intake? Could be from anything in the intake stream. What was atmospheric at the time?

a 3" cai is only a hair under 76mm... could be that.

I agree with this dude^^^^

I don't know what the da was. I know average humidity was 86 and probably low 50s. Prob ~20' above, sea level maybe less. Sea level psi was 30.97

He also brought up the cai. Thought about building one. But would it cause 93 kpa across the manifold?

I would think if there is vacuum in the manifold the restriction would tend to be before the manifold...

It absolutely could and would, hell the air filter can cause that in the intake. Anywhere between the restriction and the intake valve will show the KPA drop.

Lol, he did make fun of my air filter.

Do y'all think just swapping the air filter is enough? Or should I go 4" with the tubing?

Thanks for the help.

If it were me I would absolutely go 4" with a new filter... why go through the process 2 times? You have something (sounds like multiple things) choking you on the intake side, just do it right.

4" inlet doesn't do a whole lot going through a factory MAF.