Sound deadening/insulating 3rd gen Tacoma

how much time should I set aside for a project like that?

 

I would at least give your self the day to do it. Should take you about a hour to pull the headliner down, another hour to put up the sound deadener, and another hour to put it back together. But, there will always be surprises, so plan for 5 hours at least.

 

Would filling up with foam isolation help dampen?

 

Foam is not a good sound insulator.

 

I really want to do my roof... it's too noisy when it rains.

 

The first time I shut a door on my Tacoma with the windows down, that sound quickly reminded me I bought a Japanese truck, lol. Or pulling the exterior door handle when its locked and it clunks back.
I thought mine having a sunroof would help with the roof panel noise, I suppose it does a good bit, but I definitely get the tin-can reminders from big raindrops or when I thought an acorn hitting the roof was a rock.

I have a bunch of noico in the garage that was destined for the aforementioned Silverado but never made it there. Itll be going in the taco, for sure. I'm not aiming for killing all the sound, I actually really dislike the disconnection I feel from too-quiet, but putting a decent area of butyl on the inside of the door skins and strategically on the roof should sort it out.

A reminder to butyl people- it need not be in every tiny spot. Butyl dampens panel vibration noise, not so much road noise. Various densities and masses of closed cell foam will do that. Also, beware you may be opening up a can of neurotic worms when you try to super deaden a vehicle... the further you go, you'll start hearing noises you didnt know were there because they were masked by the louder sound you just fixed.

 

Closed cell foam is a great sound insulator!

 

https://youtu.be/V1dD1qJSr20
This says it does not.
My experience also tells me it doesn't. We use the foam as a Medium to stop vapor travel between bays in a commercial setting. We tried it to reduce noise. It did not help. We were thinking the insulation application company who told us we were wasting our time could not be correct so we spent the money anyway. Well they were right. 2" layer of spray foam cut so very little noise it was a waste.

 

that is a different type of foam! Ccf is very dense and heavy non porus foam.