Speedtoys

What is inside, and where does the cavity behind the door striker lead to?

Ive been passing around a microphone to follow noise cavities in the car, and there's a lot of exhaust tone and road noise that comes from this area/cavity.

Just wondering, structurally..whats in there..how far does it go back, is it closed or open to the interior anywhere?

Lizard928

On the chassis side this ties into the front frame rails, which are right by the exhaust manifolds.

You are likely finding a resonance effect from that. Maybe cover the engine compartment frame rails with dynamat to dampen the sound getting in there...

BigAl1

I'm currently tearing out my interior, and Colin's comment above makes me wonder if filling the frame rails in the lower door sills with expanding foam or some sort of sound absorber would help keep the sound from travelling down these tubes to the rear? Maybe a good sound path to block?

Rob Edwards

Forgive me if I'm misunderstanding, but by striker you mean the plate mounted to the rear of the door frame, that is captured by the door latch? If so, it is mounted with a trio of bolts whose tips are just hanging in space in the rear wheelwells, you can see them behind (in front of?) the fuel supply hardline in the right rear wheelwell. Dunno what liners you have on your '88, but there's plenty of potential for noise from the rear wheelwells, of course. Can't wait for Jerry to work his magic.

NoVector

Jeff - No wheel well liners in my car so it was easy to take a couple pics. Nothing in there; except on the passenger side, it looks like fuel hose. The screws you see I believe are the back side of the striker plate. Would be a great place for some single-cell foam!

/ Bruce

4drgl

I wouldn't fill those with expanding foam... You'll very likely cause rust forming from inside out, as the condensation that builds up inside the chassis won't be able to escape the foam, then it'll stay damp, and rust...

I would just dynamat things, to dampen the resonance's you're picking up through the metal frame work.

Speedtoys

Yup..thats the ticket Rob.

Jim M.

There have been several write ups on this. I've filled my cavaties with closed cell foam then the expanding foam to solidify everything. It makes a huge difference in the noise transmitted into the passenger compartment. Did this almost 7 years ago and no signs of any corrosion, and my car is a daily driver in all/any weather we get here in Texas. Currently the GTS is missing both WW liners, but I do have the early S4 small liners on both front and rear of each WW.

karl ruiter

If you are thinking of doing the expanding foam thing, I would consider fitting the area with a plastic bag, and then filling the inside of the plastic bag. That way you can remove it if you want later without leaving residue.

Andy Kay

+1 w/ Jim. I used a blue closed cell foam pad and Great Stuff Foam from a spray can. Made a huge difference. The pad came from Wal-Mart Sporting Good Department for less than $6. It's designed to go under your sleeping bag.

Nicole

The 91 and later models have some sort of foam in the B-Pillars, but not far enough down to where the door striker is. In combination with the insulated rear wheel liners and thicker foam under the carpets, it was supposed to reduce cabin noise by 3 dB.

IIRC, the door sill is part of the interior cabin ventilation; if you block it, there is no way for air to escape from the interior. It would not be a good place to add foam insulation.

Erik N

What a great idea!

Speedtoys

Pictures?

Andy Kay

Here's a pic of the passenger side rear wheel well. The tank and lines are wrapped in blue closed cell foam then filled it in with The Great Stuff. The wheel liner was then reinstalled. This may not be an option for you based on your climate but I live in Texas. I got the idea from Jim M. who did this 7 years ago and has had no issues. He lives in Texas too. My ride is now very quite and no noise is coming from the B-pillar but only you can decide if this is right for you.

terry gt

just another way to create rust problems. Up here that would trap salt and moisture .Is it fire proof ?