Hole in fiberglass body

[outatym2001]

The early VIN DeLoreans have a 2-3\8” (6 cm) hole in the fiberglass body as shown in the pictures I took.
The exterior of the hole is surrounded by a foam ring which after thirty years has basically deteriorated. The exact VIN cut off I don’t know as not many people have removed the rear interior vinyl wall panels to see this hole next to the 4 x 10 speaker.

[jawn101]

I've often wondered what these holes were for. Any idea? Ventilation? Mouse doors?

[BigBenb84]

I had them too, #2543. Noticed when I was replacing the speaker. I got the fiberglass kit from walmart and fiberglassed them over.

That dynamat? How much of a difference is there?

[jawn101]

I had them too, #2543. Noticed when I was replacing the speaker. I got the fiberglass kit from walmart and fiberglassed them over.

That dynamat? How much of a difference is there?

I just finished the dynamat of my whole interior as well and it does make a difference, most noticeably at highway speeds. Doing the rear of the car like that helps isolate engine noise, and doing the tunnel/footwells/floors helps isolate road noise. It wasn't an immediate shift from noisy to silence, but it dulls the roar just enough to make it a more enjoyable drive. You don't lose all the road and engine noise which I'm glad for, but you lose the rubbermaid-tub-over-your-head boominess.

[DMC5180]

Jon,

I thought yours was still a work in progress from the looks of the last photo's you posted. You have the whole interior back together know?

[jawn101]

Jon,

I thought yours was still a work in progress from the looks of the last photo's you posted. You have the whole interior back together know?

Yup! See attached. These are of course before the interior went back in, which was last night's big job :) After I got the steering sorted this morning I spent the rest of the day driving.

[DMC5180]

The early VIN DeLoreans have a 2-3\8” (6 cm) hole in the fiberglass body as shown in the pictures I took.
The exterior of the hole is surrounded by a foam ring which after thirty years has basically deteriorated. The exact VIN cut off I don’t know as not many people have removed the rear interior vinyl wall panels to see this hole next to the 4 x 10 speaker.

Mark, how close are you to finishing this project? Yours is by far the most complete coverage I've seen yet. Can't wait to here the results of this. Do you have an upgraded Exhaust?

[DMC5180]

Yup! See attached. These are of course before the interior went back in, which was last night's big job :) After I got the steering sorted this morning I spent the rest of the day driving.

Cool , I must have mixed you up with someone else that was also building a new custom center console.

[jawn101]

Cool , I must have mixed you up with someone else that was also building a new custom center console.

Oh yeah not me. I'd love to have a new original-style one made from plastic rather than paperboard, but beyond that...

[jfirios]

I am building a completely new center console. I did my entire car in dynamat too. Everything from the back wall to the shelf all the way to up under the steering wheel and glove box, Even inside the battery compartment and the cubby hole which will house a 12in sub. The battery compartment I am going to use the shiny Dynamatt skin to help with an LED strip I placed in there to back light the new battery door I am building which will have the DMC Logo with two lightning bolts under it illuminated.

[jfirios]

Yup! See attached. These are of course before the interior went back in, which was last night's big job :) After I got the steering sorted this morning I spent the rest of the day driving.

You did a great job with you matting. I did mine completely over the center as well.

[Nicholas R]

I've often wondered what these holes were for. Any idea? Ventilation? Mouse doors?

I read in some old DeLorean literature that they were there to help equalize the pressure when the doors were closed. I guess they were worried that you could close the door and there would be an abrupt pressure increase in the car hurting peoples ears. Later they realized that it was not necessary and that they were just holes for water and mice so they quit adding them.

[jfirios]

well, someone had to think of the water and the poor mice. :)

[jawn101]

You did a great job with you matting. I did mine completely over the center as well.

I thought about doing the top of the tunnel but decided that the tolerances are tight enough up there and didn't want to interfere with the armrest and console switches, etc. But thanks for the compliment :) I feel like I could have done a better job but it was my first time doing surfaces that large.

[jawn101]

I read in some old DeLorean literature that they were there to help equalize the pressure when the doors were closed. I guess they were worried that you could close the door and there would be an abrupt pressure increase in the car hurting peoples ears. Later they realized that it was not necessary and that they were just holes for water and mice so they quit adding them.

Wow, that is actually a completely reasonable explanation. Of course it seems like one of those things that would normally have been debunked in the prototype phase, but perhaps they had no desire or reason to try. Another interesting piece of DeLorean history.

Have those of you who have sealed these holes up noticed any difference in humidity, HVAC effectiveness or noise? I would think it would be pretty subtle if even discernible.

[Bitsyncmaster]

Not sure if I have that hole but when I run the fan on speed 3 or 4 and the AC is not on MAX, I get a whistle from the air somewhere. If I crack the window the whistle will stop.

[DMC5180]

Not sure if I have that hole but when I run the fan on speed 3 or 4 and the AC is not on MAX, I get a whistle from the air somewhere. If I crack the window the whistle will stop.

Positive air pressure build up when your pulling in fresh air. You might not have them. Then again, that air has to go mostly through the Speaker vents to get to the exit.

Interesting to note, there is a gap filler seal between the quarter panel and the underbody that directs exiting cabin air out through the Q-panel Vents. They are not just decorative, but actually function sort-o-speak.

[DMC5180]

I read in some old DeLorean literature that they were there to help equalize the pressure when the doors were closed. I guess they were worried that you could close the door and there would be an abrupt pressure increase in the car hurting peoples ears. Later they realized that it was not necessary and that they were just holes for water and mice so they quit adding them.

I've been in a couple cars where pressure build up was an issue. You would have to crack the window in order to close the door. You could also feel the pressure in your ears. The typical reason this would happen was due to debris build up (leaves,dirt etc) plugging the exit vents. It's a very valid reason to have them.

It could be the shape of our doors and the inertia generated in the closing process, we don't need the cabin vents. But when I have the Cabin Fan ON and I crack the window the the air flow feels like it doubles from the Duct vents. That tells me we would benefit from having them to some extent, not that we necessarily need them though.

[jfirios]

I thought about doing the top of the tunnel but decided that the tolerances are tight enough up there and didn't want to interfere with the armrest and console switches, etc. But thanks for the compliment :) I feel like I could have done a better job but it was my first time doing surfaces that large.

I dont think it would have any issue with the switches or console. The center console is actually above the tunnel with a lot of room under it. I wanted to just cover the whole thing. Figured while the interior is completely appart might as well leave no stone unturned. Check out the thread in the mod section for the indash Ipod. I have some photos of the dynamat in my car.

[thirdmanj]

My search on you tube came up empty. So, does anyone know of or have a before and after Dynamat video of a DeLorean?

[jawn101]

My search on you tube came up empty. So, does anyone know of or have a before and after Dynamat video of a DeLorean?

As I was putting the seats back in mine yesterday I remembered that I own a decibel meter from when I worked on custom audio many years ago. I was really mad at myself for not taking before and after readings. :(

[thirdmanj]

As I was putting the seats back in mine yesterday I remembered that I own a decibel meter from when I worked on custom audio many years ago. I was really mad at myself for not taking before and after readings. :(

Shucks.

[DMC5180]

As I was putting the seats back in mine yesterday I remembered that I own a decibel meter from when I worked on custom audio many years ago. I was really mad at myself for not taking before and after readings. :(

Well, crap. I've been wanting someone to do a Decibel comparison before and after. Especially with an Upgraded Exhaust combination.

[jawn101]

Well, crap. I've been wanting someone to do a Decibel comparison before and after. Especially with an Upgraded Exhaust combination.

I'll loan the meter to anyone who volunteers to do this :)

[outatym2001]

I had them too, #2543. Noticed when I was replacing the speaker. I got the fiberglass kit from walmart and fiberglassed them over.

That dynamat? How much of a difference is there?

Please see my pics in post number 16 and post 27 and I have a lengthy description in post 30.
New carpet, soundproofing, and dynamat – any tips?
http://dmctalk.org/showthread.php?439-New-carpet-soundproofing-and-dynamat-any-tips



Mark, how close are you to finishing this project? Yours is by far the most complete coverage I've seen yet. Can't wait to here the results of this. Do you have an upgraded Exhaust?

My sound insulating project is already complete. It took several years of daily driving the D and adding sound insulating when I wasn't busy doing other stuff. Please read the above thread for my comments. I’m happy to answer more.

I have the original exhaust with a hollowed out catalytic converter. I can’t do anything about the engine noise (sound) that passes through the rear window. Sometimes I wish there was less engine noise while idling at a stop light. With all that sound insulating I now notice more wind noise from the bottom of the doors. They don’t seal well at all.
Try this. Open your doors and lay a sheet of paper on top of the carpeted door sill and rubber door seal. Now close your doors. Now pull on the paper. You will notice no resistance since the rubber seal doesn’t actually reach the stainless steel door.

[dvonk]

...when I run the fan on speed 3 or 4 and the AC is not on MAX, I get a whistle from the air somewhere. If I crack the window the whistle will stop.

mildly related: this happens on my Jeep. the hard top has vents in the back, but the soft top doesnt. when the soft top is on, the air has to find little cracks around the door and vinyl windows to seep out and makes a light whistling sound. it also inflates the soft top and makes the top bubble upward. :lol:

if i crack a window it stops as well.