Soundproofing a pick-up

[Goosey]

Obviously I can put some dynamat or something on the top of the engine bay, but what else can I do? I don't really have a flat firewall behind the engine, and this seems to be quite open to let air through from the vents at the side. Short of putting a huge mattress over the flat bed I can't think of what else to do. Anyone any ideas? I've got a half-decent stereo now that's still competeing too hard with the engine!

 

[Clem]

Can you not get access in from the under bed lockers to the final bulkhead point, where it meets the single cab and insulate that panel? That should be the point of entry for transmitted noise.

 

[aspro]

Strange as my cab is quiet with a stock set up.

You can definitely access the firewall through the underbed locker. Perhaps you can put some insulation over it as Mike has suggested.

 

[Goosey]

I could insulate behind the bulkhead I suppose, yes. I was just wondering whether I could do anything further back, nearer the engine.

 

[aspro]

See my previous post Goosey. You could take off the access panels in your treasure chest and insulate the firewall between the fuel tank and the engine bay. Make sure whatever you use is fire rated.

 

[Goosey]

Hi aspro, sorry to ignore your last post :?

The wall between the engine and the fuel tank has large holes in it which I assume are there for air for the engine as the slots in the body are in this space too. Would I not be blocking air by insulating over these? If I don't cover the holes, there doesn't seem to be any point in insulating it as I'd be defeating the object.

 

[Goosey]

This is a pic of the engine bay:

With the holes at top right and left.

 

[aspro]

What if you insulate the access panels in the treasure chest? Also do you have insulation above the engine at all?

 

[Goosey]

No insulation above engine and yes, I could do the access panels.

 

[vwed]

I agree with aspro above; why is your engine so noisy that you feel the need to insulate? My cab is perfectly quiet, far more so than a kombi/camper. Exhaust set-up?

 

[Goosey]

Maybe it's the exhaust, although it doesn't have any holes or anything wrong with it. This is my first pick-up, so I don't know what to expect really.

 

[aspro]

I think you've found the problem. Being a SC it should be quieter than a tintop as the engine isn't in the van. Insulate the engine bay first with the tar boards. Rackhams do a good repro board. See how that goes. Should be enough.

 

[Goosey]

Okay, I'll try that first, thanks.

 

[Trikky2]

The pancake filter will create a fair bit more induction noise. You will find the engine runs quieter with a stock filter.