Joel’s SL-C Build Thread

[Joel K]

This post covers the fabrication of the subwoofer enclosure.

I am currently installing the sound dampening and carpeting. One item on the to do list was to locate and install the sub woofer enclosure.

Figured a nice place for the sub enclosure is deep in the passenger footbox. The challenge being to make the sub box large enough with the correct volume to sound good but not too large and interfere with the passenger’s feet. You also need it shallow enough to install it with the AC evaporator in place. This just clears it.

I bought a long throw 8” JL Audio subwoofer a couple years back and recently found a wedge shaped enclosure on eBay so I ordered it…

That sub box is really the perfect size and shape, but unfortunately the woofer I purchased was too deep to fit in the case. Note to self, “buy the enclosure first then the subwoofer”. I guess what is one more part to fabricate? So I got to work!

I used this subwoofer calculator to design a wedge enclosure and maximize the volume.

Subwoofer Enclosure Calculators, Parallel, Series, Port Length and Volume

www.the12volt.com

I drew out the dimensions on paper and transferred it to the 3/4” medium density fiberboard. The enclosure is 11”x9”x4.5”, a little taller and deeper than the eBay enclosure…

Then used a magnetic angle finder on the saw blade to dial in the right angle for the beveled end and face panels…

Used Tie-Bond 3 Ultimate Wood Adhesive and some clamps to assemble the back portion of the enclosure…

To glue on the front panel on I used a ratchet strap and an old table to tightly hold the back and front panel together…

Epoxied 3/4” 8-32 threaded inserts to secure the sub woofer driver. Also fabricated a 3/8” thick mounting plate. The sub woofer enclosure is held in place from the bottom of the chassis with 4 M8 screws…

Used some lightweight felt fabric and covered the sub enclosure. Pic of the front…

I watched some YouTube videos on how to carpet a sub enclosure. I think the sides came out pretty good…

Installed the sub driver…

Pic of the finished sub enclosure placed in the foot box…

I’m 6’2” and with the seat all the way back I barely touch the sub with my toes so figure I’ve got enough room for most passengers. The sub has a grill which I’ll install to prevent the sub from being damaged.

Next posts will cover applying the sound dampening, heat block and carpeting!

 

[Jon]

This post covers the fabrication of the subwoofer enclosure.

I am currently installing the sound dampening and carpeting. One item on the to do list was to locate and install the sub woofer enclosure.

Figured a nice place for the sub enclosure is deep in the passenger footbox. The challenge being to make the sub box large enough with the correct volume to sound good but not too large and interfere with the passenger’s feet.

I bought a long throw 8” JL Audio subwoofer a couple years back and recently found a wedge shaped enclosure on eBay so I ordered it…
View attachment 148564

That sub box is really the perfect size and shape, but unfortunately the woofer I purchased was too deep to fit in the case. Note to self, “buy the enclosure first then the subwoofer”. I guess what is one more part to fabricate? So I got to work!

I used this subwoofer calculator to design a wedge enclosure and maximize the volume.

Subwoofer Enclosure Calculators, Parallel, Series, Port Length and Volume

www.the12volt.com

I drew out the dimensions on paper and transferred it to the 3/4” medium density fiberboard. The enclosure is 11”x9”x4.5”, a little taller and deeper than the eBay enclosure…
View attachment 148565

Then used a magnetic angle finder on the saw blade to dial in the right angle for the beveled end and face panels…
View attachment 148566

Used Tie-Bond 3 Ultimate Wood Adhesive and some clamps to assemble the back portion of the enclosure…
View attachment 148573

To glue on the front panel on I used a ratchet strap and an old table to tightly hold the back and front panel together…
View attachment 148567

Epoxied 3/4” 8-32 threaded inserts to secure the sub woofer driver. Also fabricated a 3/8” thick mounting plate. The sub woofer enclosure is held in place from the bottom of the chassis with 4 M8 screws…
View attachment 148568

Used some lightweight felt fabric and covered the sub enclosure. Pic of the front…
View attachment 148569

I watched some YouTube videos on how to carpet a sub enclosure. I think the sides came out pretty good…
View attachment 148570

Installed the sub driver…
View attachment 148571

Pic of the finished sub enclosure placed in the foot box…
View attachment 148572

I’m 6’2” and with the seat all the way back I barely touch the sub with my toes so figure I’ve got enough room for most passengers. The sub has a grill which I’ll install to prevent the sub from being damaged.

Next posts will cover applying the sound dampening, heat block and carpeting!

I read “I found a wedge shaped enclosure on ebay” and thought…. “Wow, I'm surprised he didn’t just fabricate it himself given his history.”

I chuckled as I read the next paragraph where you basically said “soooooooo, I’m going to fabricate this”

Great work and nice write up as always!

 

[Kyle]

I put a powered sub in the same area. Less than 4in deep, no need for external amp.

 

[Joel K]

I put a powered sub in the same area. Less than 4in deep, no need for external amp.

I remember your setup. It gave me the idea of where to put the sub.

I have a 5 way amp which will power all the speakers plus the sub. That will mount under the dash on the passenger side.

 

[Alex]

The SLC is a cool ride and I hope the AC system will blow “Cold As Ice” with a leak free system…
View attachment 137626

This post covers crimping the AC Hoses. I debated bringing the hoses to an AC shop, but was concerned they would not be clocked properly so purchased a hydraulic crimping tool from Amazon.

This brand is called ISOBAD, but looks like the same product is sold under various brands. Anyway, it was relatively inexpensive at $115. It comes with all the die sizes you need and a hose cutter which worked really well…
View attachment 137627

I applied a light coat of grease on each ferule to help the crimper work consistently. Seemed to work very well. The crimps are even and well defined. Close up of a #6 hose crimp…
View attachment 137628

Evaporator #6 and #10 hoses crimped…
View attachment 137631

The #6 hose connecting the drier to the evaporator was a little tricky. When you Crimp the hoses it tends to increase the length by about an 1/8”. So to make this hose, I crimped one side then cut it so it was 1/8” shorter than needed and it worked out perfect. It took two tries…
View attachment 137632

Compressor #8 and #10 hoses crimped…
View attachment 137629

#8 and #10 rear hoses which connect to bulkhead fittings crimped…
View attachment 137633

#10 front hose connecting to bulkhead fitting crimped…
View attachment 137635

#8 front hose connected to the bulkhead fitting crimped…
View attachment 137634


To my eye, all these crimps look really good. Fingers crossed the system is leak free! That was actually a fun task.

Hi Joel,
where did you order you bulk head fittings? do you have the parts #s?
thank you

 

[Joel K]

Hi Joel,
where did you order you bulk head fittings? do you have the parts #s?
thank you

I didn’t keep track of all the part numbers, but I either used Vintage Air fittings which you can look up on their site to get the part numbers and order from summit. The non vintage air fittings I bought from coldhose.com. I definitely bought a #8 and #10 90 degree bulkhead fittings from cold hose.com. Coldhose.com fittings are very well priced and the quality seems very good.

 

[Alex]

I didn’t keep track of all the part numbers, but I either used Vintage Air fittings which you can look up on their site to get the part numbers and order from summit. The non vintage air fittings I bought from coldhose.com. I definitely bought a #8 and #10 90 degree bulkhead fittings from cold hose.com. Coldhose.com fittings are very well priced and the quality seems very good.

thank you for the quick answer! I will check

 

[Darius Rudis]

I bought extra/more A/C fittings from Summit Racing. Crimper was found on Amazon. The 4-port manifold was Summit Racing, but NOT their cheap version (that one the threads sucked and they just credited me back).

 

[Joel K]

Time to finish applying the sound dampening. I did the fuel tank compartment back on post #496. Now on to the passenger seat and foot box areas.

I went with 2mm thick Damplifier pro from Second Skin Audio. It is pretty easy to apply except in the foot-box area where it is hard to see and reach to align the pieces.

Also, if you have threaded holes or other obstacles like brackets on the chassis it takes a bit of time to install leaving access to those items.

Here are a few install tips…

• For screw holes I make pointed studs and screw them into the panel. With the backing still on, then press the Damplifier on the studs and they will pop through. Drill them out with a step drill lightly coated with WD40. The WD40 dissolves the butyl rubber base and helps the rubber avoid sticking to the drill.
• In some cases the holes need to be larger than the screws so I use a washer and sharp blade to cut the material away.
• To cut around already installed bolts and washers. With the backing still on I first use scissors to expose the bolt head, then use an aluminum template, hole saw, or socket larger than the diameter and mark the hole with a sharpie. Then use curved scissors to cut the material away.
• To install the sheets I would peel and fold about a 1” border backing along one side. Make sure it is aligned or plumb. Once I know it’s lined up well, press that edge into place. Then peel the rest of the backing off a few inches at a time and press. Use a wood roller to press out. I tried a few approaches and this way seemed to work best.

Pic of the finished chassis top. You can see all the holes to mount various electrical components. Decided to leave the chassis bare where the weatherstripping will go…

Pic of the underside of the passenger foot-box. Cut outs to feed the AC/Heater plenum and evaporator brackets…

Pic of the underside of the driver foot-box. Cut outs for the steering column standoff mounts…

Before I did the foot-box I wanted to seal up the lower fork pickup blocks. In hindsight I should have used some silicone sealer when installing the blocks. So at this point masked off the area and will use a urethane sealer. A little tricky to mask this area off…

Applied polyurethane sealer…

Pic of the passenger foot-box done…

Pic of the Driver foot-box done…

Pic of the passenger compartment done. Kept the surface bare for the seat, lap and sub belt brackets, and side impact bar mounts…

Another view, completed all the center chassis members as well…

A ton of work, but it should make a nice base for heat/sound block and carpeting…

In total I’ll use about 80 square feet of Damplifier Pro. I estimate this added 50 pounds to the car. Well worth it if it makes driving the car more enjoyable. Next up to install the heat/sound block and carpeting.

 

[Neil]

Time to finish applying the sound dampening. I did the fuel tank compartment back on post #497. Now on to the passenger seat and foot box areas.

I went with 2mm thick Damplifier pro from Second Skin Audio. It is pretty easy to apply except in the foot-box area where it is hard to see and reach to align the pieces.

Also, if you have threaded holes or other obstacles like brackets on the chassis it takes a bit of time to install leaving access to those items.

Here are a few install tips…

• For screw holes I make pointed studs and screw them into the panel. With the backing still on, then press the Damplifier on the studs and they will pop through. Drill them out with a step drill lightly coated with WD40. The WD40 dissolves the butyl rubber base and helps the rubber avoid sticking to the drill.
• In some cases the holes need to be larger than the screws so I use a washer and sharp blade to cut the material away.
• To cut around already installed bolts and washers. With the backing still on I first use scissors to expose the bolt head, then use an aluminum template, hole saw, or socket larger than the diameter and mark the hole with a sharpie. Then use curved scissors to cut the material away.
• To install the sheets I would peel and fold about a 1” border backing along one side. Make sure it is aligned or plumb. Once I know it’s lined up well, press that edge into place. Then peel the rest of the backing off a few inches at a time and press. Use a wood roller to press out. I tried a few approaches and this way seemed to work best.

Pic of the finished chassis top. You can see all the holes to mount various electrical components. Decided to leave the chassis bare where the weatherstripping will go…
View attachment 149556

Pic of the underside of the passenger foot-box. Cut outs to feed the AC/Heater plenum and evaporator brackets…
View attachment 149557

Pic of the underside of the driver foot-box. Cut outs for the steering column standoff mounts…
View attachment 149558

Before I did the foot-box I wanted to seal up the lower fork pickup blocks. In hindsight I should have used some silicone sealer when installing the blocks. So at this point masked off the area and will use a urethane sealer. A little tricky to mask this area off…
View attachment 149559

Applied polyurethane sealer…
View attachment 149560

Pic of the passenger foot-box done…
View attachment 149561

Pic of the Driver foot-box done…
View attachment 149562

Pic of the passenger compartment done. Kept the surface bare for the seat, lap and sub belt brackets, and side impact bar mounts…
View attachment 149563

Another view, completed all the center chassis members as well…
View attachment 149565

A ton of work, but it should make a nice base for heat/sound block and carpeting…
View attachment 149564

In total I’ll use about 80 square feet of Damplifier Pro. I estimate this added 50 pounds to the car. Well worth it if it makes driving the car more enjoyable. Next up to install the heat/sound block and carpeting.

Is Damplifier Pro flammable?

 

[Joel K]

Is Damplifier Pro flammable?

In general, butyl rubber is not flammable but will burn if the whole car is on fire.

 

[Joel K]

This post covers the carpet install. In general I wanted to use material under the carpet to help block heat and noise. These are the layers used:

Layer 1)Damplifier Pro from Second Skin - 2mm butyl rubber sound deadening material
Layer 2)Overkill from Second Skin Audio - 1/8” adhesive backed closed cell foam
Layer 3)Garolite Flame Retardant sheets(Qty 3) McMaster Carr PN 85345K166 - 1/32”x36”x48” sheets
Layer 4)German Velour carpeting from GAHH.com - Nice carpet used in Porsche cars

I wanted to keep these layers relatively thin and total thickness is less than 1/4” not including the carpet.

The Damplifier deadens vibration and the closed cell foam blocks sound and heat. On the exterior surfaces(front, rear, and sides) I am using 3/16” fiberglass based insulation. That should provide a very effective layer of insulation and prevent heat from overwhelming the passenger compartment.

The other goal was to make the carpet sections removable and not glue them to the chassis on top of the closed cell foam or sound deadening. So decided to mount the carpeting and closed cell foam on opposite sides of the Garolite sheets.

I chose 1/32” thick sheets which are stiff enough not to lose shape when attached vertically and lay flat when attached horizontally for the floor sections. They are also very bendable to get them into place, pretty much the perfect material for this application.

Here is a video on the process…

Made patterns out of 65 lb card stock paper. Pic of the patterns in place…

Transferred the patterns to the Garolite sheets and used a yard stick clamped to the sheets to cut perfectly straight with an oscillating tool…

Cut out all the holes and placed back in the car. Got them to fit as close enough together so there is no gap in the corners when the carpet is attached. That took some minor trimming to get right…

Attached carpet to Garolite with 3M 90 spray contact cement. The approach I took was to oversize the carpet and glue it on. Once the glue is dry, used a clean razor blade and x-acto knife to trim each piece up. Also placed slits for pull straps in some pieces. This is to make it easy to remove them when necessary…

Pic of the floor panels trimmed up and pull straps installed. I used 1.25” polyester carpet banding for the straps and epoxied them in place with some fiberglass joint tape…

Pic of the closed cell foam on the reverse side. Really happy with the results…

Hand sewn the carpet edges(Serging) to prevent fraying and provide a finished edge where needed…

Pic of the driver side footbox completed. You can see the serging around the extended footbox opening…

Passenger side…

Full pic of all the carpet sections, very satisfied with the results…

Now that the carpet is done I can install the AC, electrical components, and pedal assembly for the final time. Fingers crossed!

 

[Brian Kissel]

Nice write up Joel. The finished job looks nice. Congrats !!

Regards Brian

 

[Joel K]

Nice write up Joel. The finished job looks nice. Congrats !!

Regards Brian

Thanks Brian!

 

[Jon]

This post covers the carpet install. In general I wanted to use material under the carpet to help block heat and noise. These are the layers used:

Layer 1)Damplifier Pro from Second Skin - 2mm butyl rubber sound deadening material
Layer 2)Overkill from Second Skin Audio - 1/8” adhesive backed closed cell foam
Layer 3)Garolite Flame Retardant sheets(Qty 3) McMaster Carr PN 85345K166 - 1/32”x36”x48” sheets
Layer 4)German Velour carpeting from GAHH.com - Nice carpet used in Porsche cars

I wanted to keep these layers relatively thin and total thickness is less than 1/4” not including the carpet.

The Damplifier deadens vibration and the closed cell foam blocks sound and heat. On the exterior surfaces(front, rear, and sides) I am using 3/16” fiberglass based insulation. That should provide a very effective layer of insulation and prevent heat from overwhelming the passenger compartment.

The other goal was to make the carpet sections removable and not glue them to the chassis on top of the closed cell foam or sound deadening. So decided to mount the carpeting and closed cell foam on opposite sides of the Garolite sheets.

I chose 1/32” thick sheets which are stiff enough not to lose shape when attached vertically and lay flat when attached horizontally for the floor sections. They are also very bendable to get them into place, pretty much the perfect material for this application.

Here is a video on the process…

Made patterns out of 65 lb card stock paper. Pic of the patterns in place…
View attachment 150651

Transferred the patterns to the Garolite sheets and used a yard stick clamped to the sheets to cut perfectly straight with an oscillating tool…
View attachment 150652

Cut out all the holes and placed back in the car. Got them to fit as close enough together so there is no gap in the corners when the carpet is attached. That took some minor trimming to get right…
View attachment 150653

Attached carpet to Garolite with 3M 90 spray contact cement. The approach I took was to oversize the carpet and glue it on. Once the glue is dry, used a clean razor blade and x-acto knife to trim each piece up. Also placed slits for pull straps in some pieces. This is to make it easy to remove them when necessary…
View attachment 150654

Pic of the floor panels trimmed up and pull straps installed. I used 1.25” polyester carpet banding for the straps and epoxied them in place with some fiberglass joint tape…
View attachment 150655

Pic of the closed cell foam on the reverse side. Really happy with the results…
View attachment 150656

Hand sewn the carpet edges(Serging) to prevent fraying and provide a finished edge where needed…
View attachment 150657

Pic of the driver side footbox completed. You can see the serging around the extended footbox opening…
View attachment 150658

Passenger side…
View attachment 150659

Full pic of all the carpet sections, very satisfied with the results…
View attachment 150660

Now that the carpet is done I can install the AC, electrical components, and pedal assembly for the final time. Fingers crossed!

Looks great Joel! Looking forward to the next installment!

 

[Tracy Nadeau]

Great video, everything was explained very well.

 

[Joel K]

Looks great Joel! Looking forward to the next installment!

Thanks Jon!

 

[Joel K]

Great video, everything was explained very well.

Thanks Tracy!

 

[DaveC]

Nice clean work.
I just realized that my shop needs a drum set for when the builds get frustrating!