Volvo C70 convertible sound system build log

[gckless 5,000+ posts]

This is fantastic. More pics OP!

 

[ducatipaso 10+ year member]

Once my C70 is lowered and I swap out the front bumper for the more square & aggressively styled Volvo XC V70 front bumper it will really change the whole look of the car. The XC V70 is kind of like a awd light duty SUV wagon, so the front bumper looks roughed.

If I would have painted the scoop & spoiler silver they would have blended in.

The attached picture is of my dads C prepared 1985 Mustang hatchback, the rear wheels are like 16 x 12 and I think the tires are almost 14 inches wide, the front wheels are 16 x 10 { I think} The front fenders & rear quarter panels are flared with sheet metal not fiberglass and it has fiberglass doors and a cowl hood. He dose Sports Car Club of America "SCCA" autocross racing. its racing in big parking lots thru course set up with orange cones, theirs like 100 to 160 cars that show up, it varies.

The cowl hood is how I get down, I had a orange & black 1980 Mustang hatchback with the body work off of a 1993 GT on it, a mach 1 style ram air cowl hood and a saleen wing / whale tail spoiler. I didn't build much of a sound system, but I did fiberglass-ed the spare tire wheel { when I was 17 years old } and tired to make a wood frame for a box that would fit with the fiberglass spare tire wheel and the rear bars of my roll cage. but my measurements were way off & couldn't figure out how to fix it.

 

[TheUnderFighter 10+ year member]

Great car... tasteful mods for sure.

I highly recommend you read: Basic Car Audio Electronics before delving any deeper into anything. And read around here for a month or two before spending any money.\

 

[IonRL205 10+ year member]

Wow dude, that spoiler, I bet you glide though 150 mph turns with that thing! And if traffic gets too bad, you can just fly over them! That car must also have a beast of a motor to have that big of a cowl hood, like holy shit, that car must whoop some ass!

When you get that sound system, all the females are going to crowd around you! That is gonna be one awesome car!

...said no one ever.

 

[slammedincouch 10+ year member]

Why didn't you just leave it the way you had it in september of 2013? Looked so0o0o much butter

 

[BoomTaco64]

Why didn't you just leave it the way you had it in september of 2013? Looked so0o0o much butter

they way you had to NASCAR out your clean looking volvo...//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif.....what is the "GO FAST" wing on the back going to do with your car as far as performance? better downforce at 150mph??? you killed the looks of your car...and the hood...oh my...//content.invisioncic.com/y282845/emoticons/suicide.gif.a649d21efc0d1fd4890a6428166586c1.gif.....good luck with the build and please stop with the exterior "performance" upgrades...you are driving 15-80mph...your not on the track, if you are, get a coupe because the convertible top is killing you.

 

[ducatipaso 10+ year member]

As for the motor in the Mustang " I think" it has 320 to 330HP its never been on a dyno for fine tuning, the mustang weighs about 2700lbs. the power is being sent thru a upgraded but still stock type T5 manual trans. The trans bolts to the bell housing with four bolts and its broken those 4 mounting taps that the bolts go thru.

The rear dif is a locker with 4.11 gear. The rear tires size { diameter } plus 4.11 gears & the motors spinning at 6000 to 6500 rpms means it has a estimated top speed in second gear of 80 to 90 mph - at least that is what I am told. When auto crossing you kind of just shift into second gear and keep it their for the rest of the course.

The rear differential / suspension has coil-overs and a part called a torque arm, when the Mustang is given gas instead of it trying to lifting the nose and transfer the weight to the rear wheels the whole car squats and is pulled / pushed down by the forces that would have other whys lifted the nose.

Ha Ha Ha the fiberglass doors have no window parts in them at all and the opening the windows would have slide up thru has been glassed over, so those fiberglass doors would be a blank slate for a stereo install.

I still need to do more research on the system for my C70, I removed the center dash a/c vent to take a look behind it and as much as I would like to install a pair of mini subs front & center, making a 3inch by like 9 panel for three gauges, and then wrapping the panel with something blue so that I have a snug fitting gauge panel might be a better option for me.

among other things my planned Volvo S60R spaceball shifter install is going to be much more complicated then I had planned, my C70's center console is a inch lower then the S60 center console and the spaceball shifter needs that extra height for it to work properly. That means I would have to swap consoles and trim my dash for it to fit, I would also have to swap the parking brake handle and a steel tunnel that the parking brake handles mounts to, but in the end I would have the spaceball shifter and a better set of cup holders.

 

[Jroo 10+ year member]

There is a lot going on here, some good and some not so good. As a former V70 owner I prefer the stock look of the Volvo but this is your car. If it were me, I would take the car up to the "R" level which was more performance than a normal Volvo and very subtle exterior changes.

Did you really say roof shingles and roll cage in the same sentence?

 

[ducatipaso 10+ year member]

I worked on the wiring for my transmission swap today "with no wiring diagram" and I think i have narrowed down the wires that trip a relay for the reverse lights & brake lights, so tomorrow I need to track down that relay - I can hear it clicking under the dash, then I need to run some wires to it and sort thru some other wires that are preventing my abs & gauge cluster from working properly.

It looks like the weather should warm up for three or four days and I can turn my attention to sound damping my doors and I will take plenty of pics.

but I don't know about using this roofing cement, its cold outside so it might be really thick, it said trowel ready on the label, I knew spreading it won't be cake boss but when I was at Target I thought it might be when I saw this cake boss cooking utensil that I thought might work as a trowel. But I didn't buy it.

Once I am done sound damping the doors, tinting the front windows, a oil change, my trans wiring, rear brake pads & new parking brake shoes, then I can move onto tinting the two rear side windows of witch will require me to remove the rear interior panels, "then I will do more sound dampening their" at the same time I will be removing the top rear seat cushion of witch will reveal the factory designed area for the rear 8's.

I was a Volvo tech and service porter at a Volvo dealer, so I've driven plenty of the twin turbo S80 T6, S70 & V70 R, S60R and 850R's, I want to improve my C70's performance but right now it has no abs, won't revs past 4000RPM and once the speed goes over 65 I loose the speedo and my brakes get worse, so when you loose your speedo your skinny dipping.

 

[Side Show 10+ year member]

lol your dads rig needs a wing.................. ohhh lord jk

 

[ducatipaso 10+ year member]

I pulled the door panels on my C70 so that I could get an idea for how to sound dampen / deaden the doors and I found a phew parts that were bolted tougher and making metal on metal contact { of witch could vibrate} and the plastic honey comb - crash crumble zone plastics inserts were a bit loose/ un-dampened and making contact with the door, so those areas could of been creating vibrations.

The window is controlled with cables and the inside of the door is much tighter then I remember it being. The doors already have a layer of sound damping matt & quite a bit of foam pad. I must have been thinking of a Volvo S70 or Volvo 850's doors when I thought their was a large degree of improvement to me made in sound damping my C70's doors.

The doors are sealed pretty good so the free air 8's have a good baffle, I am thinking that I will tape off everything I don't want to get the roofing cement on and then just try to improve what is their and cover as much of the metal as I can with a layer of roofing cement and then stick a layer of foam to it. I will cut the shingles into the right size pieces, preheat them and then mold them and seal them into place.

As I do the doors I want to keep my long term goal in mind of bringing the subs up level with the door panels so the sound waves aren't limited to only coming out of a speaker grill that is less then half the size of the 8. I've been taking pics but I need to buy a new micro memory card before I can upload the pics.

I was looking at the inside of the door panels also for anything loose or making contact with the door that could rattle and the door panels looked pretty good, but I suppose when your working with a car that had a $43,000 msrp when it was new the car should be a quality foundation to build from.

When I look at the doors & the area that the 8"'s mount to, for me to bring the 8"'s up I would need to make wooden rings that go around the sheet metal that supports the 8's and build up a surface for a new speaker mounting surface. And then cut into the door panel so that it could fit next to the new speaker enclosure.

The lower area of the door is were the 8" sub is, The black arrows are pointing to were the clips are that hold the panel on, I kind of like the idea of cutting along the doted orange line and then up & around the sub. So that I can make the lower area into a shelve for the door panel to mount to and then it could slide behind a lip on the speaker enclosure.

{orange arrows are screws going up and yellow arrows screws going down.}

Then I could cover that whole lower area & speaker enclosure with some type of blue material and fit the door panel onto it. I've never do anything like this but I think it would look excellent & accomplish the goal of bring the 8' to the surface.

 

[ducatipaso 10+ year member]

I used up 22 or 23 feet of blue tint trying 6 times to tint the drives side window and I had a crease I couldn't get out each time, so while I wait for another roll of tint I am preparing to work with these shingles, roofing cement and foam matt so that I can start sound damping my C70. The weather was warmer today but the viscosity / thinness of the roofing cement has been on my mind.

My first though was to warm it in a crock pot but I decided to purchase a 1100watt hot plate instead and I will just put the can of roofing cement on the hot plate. Since I am trying to adjust the temp of the roofing cement I figured I needed a thermonater to gauge its temp so I purchased a cheap meat thermonater. I figured that I would need something to stir it with so I purchased a cheap steal ladle.

I can use the ladle to stir the cement and use it to transfer some cement from the can to the work surface. By heating the roofing cement it should flow better and as it cools the outside skin should be thicker and harder then the normal curing. The added heat should also make it stick and bond to the shingles better.

I want to heat the shingles so they are easier to cut, conform to curves better & bond better with the cement. I am debating between using 2 electrical irons to heat the shingles or a toaster oven & then rotate 4 small sheet pans of shingle pieces in and out of the toaster oven.

After I sound dampen the doors then I will take a closer look at the door panels and decided if I want to go purchased some mdf and dig the router table out of the attic, the router table hasn't been used for years.

 

[gckless 5,000+ posts]

WTF. Either this guy:

Or a really good troll. I can't decide.

 

[ducatipaso 10+ year member]

Well today I set everything up to test the roofing cement & took lots of pictures.

When I opened the can of roofing cement it was black & shinny and the texture looked dense. It looked to have maybe three different sizes of matter, a bonding paste and two or maybe three larger textures.

I dipped a steel ladle in to scoop out some cement and it came out with easy but then it didn't want to come out of the ladle.

Last week I purchased a 1100 watt hot plate and today I a purchased a small sauce pan with a lid from the thrift store. So I scooped the roofing cement into the sauce pan and heated it.

On the label it said - do not heat container not - do not heat continents of container / roofing cement, so I put the cement in a sauce pan. The cement didn't have much odor and I heated it to 150 degrees, it softened up some but it didn't melt into a pourable liquid at that temp.

I laid out 10 sample pieces of roof shingle, cereal box card board, thin foam matte, metal & plastic screen. Then I spread around the gooey black cement and watched its texture as I worked with it and bonded tougher different combinations of samples. Then I set them aside to cure, after they cure I will test the adhesion, tensional strength & its flexibility it feels.

At the last minute I decided to use a piece of screen as a test piece and the cement worked very well with plastic screen. I put a gob of the cement on a piece of cardboard and then laid the screen on top and used another piece of card board to spread the screen into the cement.

The screen conformed to the shape of the cement and a percentage of the cement pushed thru the screen. I was pleased by that.

I made a bit of a mess when trying to work the cement into the cavity of my C70's upper motor mount but it was another chances for me to work with the texture of the cement.

I wasn't wearing rubber gloves and without thinking I dipped my finger in to get another gob of cement, then it occurred to me that it might be hard to clean the cement of my hands.

But when I purchased the roofing cement I also purchased some low grade paint thinner and the paint thinner dissolved the cement very quickly.

On the front of the label it said for vertical applications and on the back it said something about possible a 30 day cure time.

The long cure time means it might not work for my C70's motor mount, becasue if I try to accelerate the cure time by using tomuch heat the oils might evaporate to quickly and cause the cement to become brittle, brake and then powder when the mount is in service.

The roofing cement is messy but when combined with roofing shingles & thin insulating foam pad it will work for many areas of my C70 sound damping project.

 

[ducatipaso 10+ year member]

I tested my roofing cement test pieces yesterday and today to check the cure time of the cement & the strength of the cement.

I tried to slowly pull the different pieces apart and it seamed to have a adhesion strength { the amount of force it took to pull them apart } of about 10 or 12 pounds of force . Today the samples strength felt more like 20 pounds and the cements bounded was the best between bare metal & a roofing shingle.

I think the testing pieces are a bit fouled now that they have been pulled apart two or three times.

So in conclusions I think the cement has the vertical { up and down } holding strength needed to hold the weight of shingles in place. After they are in place I will apply a overlapping layer as added insurance they won't fall off and the extra cement will add more to the damping effect.

On my C70's front door I think I will use a combination of cut pieces of shingles, roofing cement and lots of thin insulating foam.