Firewall insulation

[VillaTA]

I’m getting ready to pull the trigger on firewall/floor insulation from hushmat. I feel like I’m getting cabin fumes from under the hood. Is this potentially coming in through the vents? Even when shut, I wonder if the seals are old and porous. I hope to get some heat reduction too. Anyone else have any solutions for this issue?

 

[moparroy]

I'd look at the cowl weather stripping under the hood top of firewall. That's the first line of defense from under hood fumes - it should direct them out to the sides away from the cowl air intake
Then seals in the heater box - I believe the heater draws air from the passenger vent even when it is closed.
It could be other seals on the firewall too - there is a number.
Insulation should help heat and sound but not sure how it would help fumes.

 

[Challenger RTA]

2nd I would check all the firewall holes and steering tube .3rd check floor seams and tunnel holes.

 

[moparleo]

Vents always pull fresh air from outside the car. Fix the fume problem in the engine compartment. Carb too rich ? Timing too advanced?
Oil leaks ?
Engine in good repair should have fumes under the hood. Factory air cleaner would vent all fumes back to the carb.
What is the story under the hood ? Pictures ?

 

[VillaTA]

Reopening this thread. I’m not feeling like I’m getting fumes as bad, my carbs do have some small leaks. I’m confident that this is where my odor was coming from. My question is, has anyone had good thermal insulation experience? I’ve read that the thin butyl products are no better than stacking another layer of sheet metal On the firewall. pricey for low efficacy.
Any thoughts?

 

[Adam]

Reopening this thread. I’m not feeling like I’m getting fumes as bad, my carbs do have some small leaks. I’m confident that this is where my odor was coming from. My question is, has anyone had good thermal insulation experience? I’ve read that the thin butyl products are no better than stacking another layer of sheet metal On the firewall. pricey for low efficacy.
Any thoughts?

I used a product called E-dead, similar to Hush mat. I think it helps quite a bit; the additional mass and rubbery material helps with heat, sound absorption and dampens vibration. Won’t help the fumes though.. cowl seal and other remedy’s as the others have said.