E36 M3 RallyCross build!

[95maxrider]

That looks amazing, great work! It's way too nice to rallycross now.

Lol, generally speaking the car looks like sh!t, I only showed the good parts

[95maxrider]

With nothing left to do to the car, I decided to busy myself with a fresh stereo install. More bass make you go faster, right? Here's a quick recap on what I've got and my thinking for the future.

The car still had its original Harmon Kardon "premium" stereo when I bought it, but a lot of the front speakers were blown out. I kept things alive for as long as I could by installing original speakers I found at junkyards, but after 4 years or so, I eventually decided to rip it all out and install new stuff. I tried to build a decent stereo as cheaply as I could, so I replaced the 3 way front speakers with a 2 way set of JBL GTOs, and 6x9 GTOs in the rear deck. Powering it was a 100w RMS x 4 RF amp. And you know what? I was pretty happy for a few years. It was worlds better than the factory setup. I eventually wanted more bass, so I added a JBL BassPro SL2 underseat sub.


One thing to keep in mind about the limitations for the stereo is that I can't have a traditional sub in a box. When I drive to a race, the car is packed to the brim with 8 wheels/tires, and all of my gear, so there's no room anywhere for something bigger than that wimpy under seat sub. And before you ask, no, I don't want to just remove the sub when I drive to races and reinstall it when I get home. I often have to drive 2 hours to get to a race, and I need that bass all the time


But over the years of listening to my very budget build (seriously, I think the total cost with the sub was less than $500), I was getting pretty fed up with its inadequacies.

First up was the front stage. The E36 has 5.25" speakers in the kick panels, which play directly into your ankles. There was pretty much no bass from the front stage. Then there was the fact that I downgraded from the factory 3 way to a 2 way setup. This forced much of the mids to be played from the 5.25s, which are incredibly off-axis. You can't see the driver's speaker when in the seat, and you can barely see a sliver of the one of the passenger side. So the reproduction of vocals was pretty bad, and I really struggled to hear things when driving.

This forced me to rely on the rear 6x9s to hear mid range frequencies, and well as most of the bass (until I got that under seat sub). So the sound stage was pretty terrible.

Adding the JBL under seat sub helped improve the bass situation, but not by much.

So after 4-5 years, it was time to upgrade again. I wanted to do it right this time, and not really leave any room for future upgrades. First thing I knew I needed was a 3 way front stage to help bring the mids back closer to ear level. My ankles just don't hear as well as they used to! I toyed with off the shelf setups in the $500 range, but it seemed a lot of options in that price range weren't actually much of a quality upgrade over the JBLs I had, they just had an additional speaker. I eventually settled on the Stereo Integrity speakers:

TM65 mkIV
M3 Carbon
M25 mkII

But of course, this meant I would need to make 6.5s fit where the 5.25s currently reside. And I would need to figure out a crossover solution, since SI doesn't offer one, and I wasn't going to run active. I picked up all the SI parts over their winter sale, so the total cost wasn't too far off what a mediocre off the shelf 3 way setup was going to cost.

I decided to piece together a crossover network made up of Dayton Audio parts. They have a pretty wide selection available:

https://www.daytonaudio.com/category...led-crossovers

I found parts for the right frequencies and impedance, but they only offered them with 12 dB slopes instead of the recommended 24 dB slopes SI recommends. Oh well. I picked them all up on sale from Parts Express at their winter sale for something like $100 total.

Next up was a more powerful 4 channel amp. I settled on a used Alpine PDX-F6 with 150w RMS per channel, partially based upon this review:

https://www.audiosciencereview.com/f...plifier.28870/

I can't say I understand any of it, but it sure sounds like a well engineered amp.

Anyways, enough talk. Let's see some pictures!

These are, without a doubt, the nicest components I've ever owner!





Old 5.25 vs new 6.5





Gosh, I really hope these things will fit. I don't have a Plan B.








It took a lot of work, and some very uncomfortable body contortions, but I was eventually able to get the 6.5s in there. Thank god they are so shallow! I did my best to seal up the cavity, but it's not perfect.





After quite a bit of trimming, I was barely able to get the factory covers to go back in place without interference.





Thankfully the mids and tweeters were very simple in comparison. I made a spacer for the mid, which I epoxied to the door card, and then screwed the mid to that. The tweeter just screwed on, super simple.





The SI grilles hadn't been released yet for the M3s, so I cut up the factory piece and glued it in place.








Far from beautiful, but it's functional. This has generally been the theme for the car.

I ran all new 16 AWG OFC cable to each speaker, which was not much fun.

Time to head to the trunk. Here's how the old RF amp was mounted. Ignore the wires, this was mid-disassembly.





The new crossovers were....slightly larger than what the JBLs came with. Quite a bit heavier too.





Which meant they couldn't be tucked up in the dash and had to be in the trunk.

So I made a new mounting board for everything and bolted it up.





And eventually wound up with this:





Another problem I wanted to address was road and exhaust noise in the vehicle. Last year I installed a quieter cat-back on the car, and while it helped, it was still a little too loud on my long trips. It doesn't help that the car runs at like 4,000 rpm at 80 mph. As you can see in the picture above, I did my best to line the entire trunk with 1 lb/ft MLV. The lower portion is easily removable when I get to my race, while the upper portion will stay in place.

I also wanted to test out another affordable and light weight option for the doors. Thankfully they didn't need any CLD since the 6.5s are in the kick panels, but I did want to keep out road noise. So I bought a box of 1" Owens Corning 703 fiberglass insulation for about $130, which is more than enough material to do all of my cars. So I got to measuring the cutting.





I then wrapped each piece in thin painters plastic and installed them in all the doors.





The rear doors were tough since the openings are so small, but I was able to get them done too.

[95maxrider]

I even tried to fill up the empty spaces on either side of the trunk, since those cavities eventually lead into the cabin.








In an effort to get rid of ground loop/alternator whine noise, I upgraded my RCA cables from some old JL cables to some World's Best Cables.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Unfortunately, they didn't solve the problem and my whine remained. The headunit I've been running for a few years has been a Pioneer DEH-S7200BHS. My only requirement for a headunit was that it had 4V pre-outs and a USB port for my thumb drive. This unit technically fit the bill for a very good price, but I think the QC was lacking.





Anyways, I'll stop here for the moment. I welcome any and all feedback, criticism, and advise. If you see something that could be done better, please let me know, I want to improve my installation in any way possible.

There's a lot more to post, but I'll stop here for now.

[Laminar]

Nice! Any plans for a compact sub upgrade or are you hoping the better components round out the bass?

[95maxrider]

After installing the SI 3-way setup in the front doors, my primary goal had been achieved. The sound stage had moved up significantly and I could hear vocals and mid range parts much better. Bass response from the SI 6.5s was better than the JBL 5.25s, but not as much as I had hoped.

I decided to take a chance and try to install the Dayton Audio UM8-22 8" subwoofers in the rear deck in an IB arrangement instead of installing better 6x9s. Their specs seemed pretty close to ideal for my setup:

300w RMS
16mm xmax
QTS of 0.64
And only $100 each when they were on sale with another discount on top.

Here's how they look next to the old JBL GTOs







Beefy

But! The factory speakers are bottom mounted and spaced down with the plastic adapter shown in the pics, and the opening in the rear deck was pretty small. I considered doing a bottom mount for the Daytons, but given that they weigh 11 pounds each, and the beating the car takes at rallycross, I thought a top mount would be a more durable solution. But of course it came with its own difficulties.

Here's what it looked like after I pulled the old 6x9s





And here's a test fit of the adapters I made, showing how much material was going to have to be cut to do a top mount:





As you can see, the mounting surface is far from flat, and has lots of strengthening ribs all over the place. Not to mention that the adapter was hanging off the front of the flat surface and had nothing under it. I had a tube of 3M Window Weld urethane lying around, so I decided to try to make a mounting surface out of it. It's strong enough to make suspension bushings out of, so I figured it would work for this too. Here's what round one looked like:





I also had to cut the deck so it was wide enough for my spacer to lay flat:





But this of course made it floppy as hell, so I had to do something to make it stiff again.








It's far from my best work, but trying to get my welder back in there under the rear glass was very difficult. In the end it worked, and the surface was nice and rigid again. Functional, not beautiful.

Then there was the problem of making all 8 mounting holes. I could only get my center punch in like 3 of the locations, as the rest were blocked by the glass, and doing it from the bottom wouldn't work due to the curves of the metal down there. It took a long time with a variety of tools (mostly my dremel), and the holes weren't all perfect, but it is functional. Making the cutout wasn't fun either due to many of the same space constraints, but it too was eventually finished.





I used CLD to space up low spots, did another round or two of the 3M urethane to fill other gaps, and used vice grips to flatten some of the raised ridges. After tightening everything down, it looked like I had a good seal around everything, and they were very secure. A test fit of the rear panel showed that I could leave it stock and not have to worry about cutting it.





The subs are DVC 2-ohm, so I wired them for a 4 ohm load to make the amp happy with 12 AWG OFC wire.

Going into this project, I had never heard an infinite baffle sub before, so I had no idea what to expect. And I was also concerned about losing the rear fill from the full range rear speakers. Not to mention each sub was only getting 150w RMS, which was barely more than the 125w that was going to my JBL under seat sub, which was thoroughly underwhelming (and now disconnected).

Thankfully, all of my concerns were laid to rest as soon as I powered them up. Without making a single adjustment to the tune, they produced tight, punchy bass and dug way deeper than what I had before. I was thrilled! I didn't for one second miss the rear fill either. My other car has a JL 12W6 in a sealed box getting 500w RMS, so while these cheap little 8s getting a total of 300w can't hit as hard, or go as deep, the disparity isn't as great as I would have assumed. In some situations, like when playing at lower volumes, I actually prefer their response to the JL. Part of that may be due to the fact that they're playing into the cabin, rather than the trunk.

So for a grand total of $200, and probably closer to $100 once I sell the JBL, I couldn't be happier. I finally have the bass I've been wanting for all these years, and I don't have to worry about a bulky sub box that I would have to remove when I go to races. I now know I can remove the rear fill speakers in my other car and go active there, and I have some first-hand experience with IB subs. Not to mention I proved to myself that this could be done at all.

As always, please let me know if you see room for improvement with the install.

But I wasn't done yet....

[Laminar]

Nice! Any plans for a compact sub upgrade or are you hoping the better components round out the bass?

Answered my question!

[95maxrider]

The next phase was to upgrade the cheap Pioneer headunit. I was tired of the front port for the USB (I've had nothing but bad luck with the shorty USBs, and the regular sized ones stick out too damn far), and I wanted to see if I could really notice an upgrade. I considered moving the Pioneer DEH-80PRS from my other car into the M3, and then getting a P99RS for it, but when I saw how much the 80PRSs are selling for, and how cheap I could get the Japanese version of the P99RS (the P01), I said F it, I'll sell the 80PRS and just get two P01s from Japan That way both cars can go 3-way active up front if desired.





For those of you not in the know, the P99RS/P01 was Pioneer's highest quality single DIN HU they ever made (as far as I can tell). They retailed for over $1,300 when new, and still go for outrageous prices since they're out of production and Pioneer never released anything close to it's quality ever again. Standout features include:

Dual L/R Independent 31-Band Equalizers
L/R Independent 4-Way Crossovers with Slope Setting
Auto EQ and Auto Time Alignment
32-Bit Binary Floating-Point DSP
Copper-Plated Chassis
and so much more


I spent hours reading through a 50+ page thread on the P99RS on another car audio forum, taking all sorts of notes along the way, trying to get a feel for how it should be setup. But first, WTF is this thing on the power cable? I've never seen anything like this before (not the fuse, the black box).






It's pretty hard to show just how little room there is behind the HU on the E36, but it's TIGHT back there. I had to remove the gauge cluster just to be able to finagle all the wires in place so the HU would click in place. Not fun!





Next, I would like to curse the person who decided it would be wise to have a freaking wiring harness for the RCA cables, instead of just regular plugs on the back of the HU. WHO DECIDED THIS WAS A GOOD IDEA, AND WHY?? It's so unnecessarily bulky.






It took a little digging, but I found a factory ground location so it would have a solid ground. It's the first HU I've seen that didn't just run the ground through the harness.





I had been chasing a ground loop/alternator whine for quite some time, going so far as to try the trick of wrapping a bare copper wire around all of the RCA outputs and to a screw on the old HU. All it did was change the pitch of the whine, but it didn't solve it. Well, I knew the P01 has excellent construction and noise rejection, and lo and behold, my whine was 100% vanquished just by installing the P01, with no other changes. Well, except the chassis ground for the HU instead of through the harness.


People weren't kidding when they complained about the (hidden) menu structure on this thing either. It's taken me well over an hour before I got somewhat comfortable going through all the setup and audio menus. It didn't help that I had to use Google Lens to translate the initial setup menu from Japanese to English. I haven't done any time alignment or auto EQ yet, since I know more changes are coming soon that would render it all a waste of time But even with the absolute minimum of tweaks to the system, I'm pretty amazed at the upgrade in sound over the old cheap Pioneer. But of course, there's more to come!

[95maxrider]

In preparation for going active and doing tuning with REW, I wanted to go back and try to improve some things that were done a little hastily in the first round of things.



First up was getting my roof/headliner situation improved. I removed the sunroof from the car years ago and installed a CF blank plate, but my attempt to fill the gap and recover the headliner left a lot to be desired. It eventually was sagging quite a bit right where I sat, and was rubbing against my helmet when I raced, so I ripped it out. Between the OEM construction and the CF plate, the roof was very resonant, and I wanted to address that before reinstalling the headliner. Six sheets of CLD later the situation was much improved.





More to come on that later as I get to it.


This is just a pic of how far I had to space out the hood release handle so it would clear the surround for the front 6.5s:





Due to the very tight confines around those front 6.5s, my initial install only had screws in 3/4 locations, which I really didn't like. So I decided to drill 4 more holes in the speaker so I could attach it more securely.





The OC fiberglass I stuffed in the cavity was touching a part of the basket, so I pulled it out





And put in a very unscientific amount of Poly-Fil in there. I have no idea what I'm doing btw if that wasn't clear.






All the wires that run above the speaker in the C-shaped cutout made mounting the speaker very difficult as they liked to hang in the way, so I drilled a hole and secured them up and out of the way with a zip tie.





This allowed me to properly seal up that hole with CLD on both sides. I also sealed up the holes that the plastic cover clips into, and plan to hold it in place with velcro from now on. With I think 7/8 screws installed for the speaker, it's now very secure, and with the extra CLD over any holes, I think it's sealed up very tight now, which I hope will improve bass response. And to be extra sure, I added CLD around the speaker in case there were any gaps I couldn't see.

[95maxrider]

Let's step back from the stereo work for a bit. The black vinyl wrap I put on the roof back in like 2017 was toast and needed to be replaced. I had bought some silver vinyl a while back, so rather than mess with repairing and painting the roof, I figured I would slap on the silver. But I had no idea how miserable it would be to remove 7 year old vinyl. Good god, I must have spent like 10 hours with a heat gun getting that crap off the car. Since it was so brittle and degraded it only came off in tiny slivers. Eventually, I got it all off.



When I installed the delete panel, I did a real shit job with making both it and the sealant level, so it looked pretty bad under the original wrap. Now I have a lot more tools at my disposal, so I smoothed things out and made it look acceptable. It's not perfect, but it's good enough for right now.



Wrapping the roof was pretty miserable, I don't plan on doing it again. It looks good enough from here, but up close there are all sorts of tiny bubbles that I couldn't see when I was smoothing things out. From here on out I'll stick to paint.



I got tired of how crappy the AC was in the car so I decided to do some digging. When it was set to the two fastest fan speeds it made a lot of noise, but I just figured this is what old German cars do, since it was like that when I bought it. Turns out that was only partially true.



The left fan blade had broken off the shaft and was just sitting in there, letting the right side do all the work. The right side had some cracks in it too. This was an absolutely miserable process, as there are like negative millimeters to work with when trying to remove/install all the parts of the blower motor. To get better access I removed the two pieces of plastic at the bottom of the windshield, breaking off much of the "rubber" (now plastic) during the process. Since I had a big balance with FCP Euro, I bought some new ones with nice supple rubber.



Much better. I also installed a new cabin air filter.

While I was putting everything back together I noticed that the fuse holder for the electric fan relay was all bulged out and looking really funny, so I opened it up for probably the first time in 7 years.



That can't be good. The plastic had melted on the fuse, but the link was still intact. I had a spare one lying around, so I installed it along with a proper terminal instead of the dinky one that was used before.



I also fixed some of the other wires involved in the electric fan, and it's working great now. I feel like I narrowly avoided an overheating disaster.

Now the AC blows nice and strong, and is very quiet as well. Can't believe I drove around like that for 8 years!

[Laminar]

That's a great color match on the vinyl! What was the brand/color code? If I still had A/C I'd probably ditch the sunroof for weight savings, too, but without AC I kinda gotta have it.

[95maxrider]

That's a great color match on the vinyl! What was the brand/color code? If I still had A/C I'd probably ditch the sunroof for weight savings, too, but without AC I kinda gotta have it.

I want to say it was a Vivid wrap, in some generic silver color. In person, it's pretty obvious it's nowhere close to a match; the amount of flake in it is outrageous compared to the factory paint.

[95maxrider]

Alright, let's get back to the stereo project.



After installing the CLD on the roof, I covered it all with 3M Thinsulate.





And was just barely able to install my badly deformed headliner. It's ain't pretty, but it's a lot better than the bare metal I'm used to!





So here was the first draft of my amp/crossover rack:






I started trimming it down and rounding off the corners





I had to glue another piece to the back since the back of the back seat has all sorts of high and low spots, and I needed to change where the bolts were going to go.






That center section goes up against the center pass through, which was barely held in place with one or two tiny tack welds. That wasn't going to be nearly enough to support the weight of the amp rack, so I welded it up.





And painted it real quick





Added some CLD





Painted the rack, mounted up and amps, and did a better job at cable management





Added some CLD to the bottom of the speaker grilles to try and get rid of rattles. It's an improvement, but it's not solved.





And then I finally got to play around and try to set the gains properly.





More on that a little later!

[95maxrider]

I made a post about this in the general E36 section, but I figured I would double post it in here as well:

Has anyone ever installed an aftermarket water temp gauge in place of the stock gauge in the cluster?

I'm considering installing a digital water temp gauge in place of the stock one since it's so freaking useless. I would like to use the one from Innovate Motorsports, since it can be set to have an alarm go off at a certain temperature, which will make the display flash and really grab your attention if there's a problem.

https://www.innovatemotorsports.com/mtx-d-water-temperature-battery-voltage.html

This way I can easily know exactly what my temp is, and also get a visual alert if it goes over whatever I set the alarm to, probably 210*. In terms of where I'd mount the temp sensor, the consensus seems to be drill/tap an aluminum thermostat housing. I considered mounting the gauge down by my shifter with my VDO gauges, but I really want this to be in my line of sight, aesthetics be damned.

Does anyone have any thoughts or advice on this before I get started?

[Laminar]

I put a wideband gauge in place of the stock coolant gauge.