It's a highly modified car that's 25 years old, IDK what to tell you, it's probably going to have some issues and lack some creature comforts. Not sure on that rear clunk, maybe the exhaust is banging on something?

Take a week to fix another issue or two and if you're still hating the car sell it and get an ND.

 

I don't hate it. Just not what I was told it was. I'm very meticulous, I fix anything that isn't how it's supposed to be. I've spent the evening googling and reading through threads and that missing bolt could definitely be a source of noise, especially since it's the one that goes into the LCA. Rear axles seem to be fairly new so I don't think they're an issue. Once I replace the drive shaft I'll see how much noise there still is back there. The exhaust is going to have to be replaced as well, at least the muffler. It rattles pretty bad and I replaced the hanger and it still rattles but if you actually hold the muffler it stops. Baffles inside are broken.

 

I'm going down the rabbit hole...
Debating just buying a new rear subframe since the holes on the bracket weren't lining up anyway. I found a torsen with half shafts an hour away, the car doesn't currently have a LSD. I'm going to spend the weekend under the car and decide if I just want to start with a new subframe and throw the torsen in while I'm at it. Are poly diff bushings worth the nvh they'll add? This is just going to be a street car but I like my cars to be tight and have as little slop as possible. I hate feeling flex in the shifter. This car isn't to bad but I feel it when getting on and off throttle.

What cat back exhaust do you recommend? I'd rather get something good now than end up having to replace the muffler again down the road.

 

The scope creep begins!

Just playing, mostly. Lol.

Poly diff bushings are going to be a make or break for NVH depending on who you ask. With poly bushings and a lightweight flywheel, my car was very grumbly on decel. I personally found them worth it for the amount of shifter slop they eliminated. However, someone seeking an OEM-like lack of resonance in the cabin might not enjoy them. Go over to Miata.net. They'll tell ya lol.

Actually, if you're on stock motor mounts, I'd upgrade those to poly or something stiffer first and then reevaluate. Much more shifter slop to be eliminated with the motor mounts vs. the diff mounts

 

It does have stock motor mounts, which I found odd. On a Honda they're the first thing to get replaced. Compared to my Honda this car has zero rattles or vibrations. I don't mind crazy nvh but my wife refused to ride in the Honda because it was so bad. So I probably don't want to go poly diff bushings lol.

I have been chatting with a Miata guy local that thinks my noises coming from the rear end are 100% going to be the drive shaft. Me noticing the other stuff, not a huge deal. He told me to take the whole brace off and see if there is any change. He doubts there will be until I get the new drive shaft in.

 

I removed my rear subframe brace for a while and ended up putting it back on. It seemed like it helped with NVH on the highway, but it's possible that I just found a particularly choppy section of road when I had it off.

If the threads are stripped for the subframe brace, can you just throw a bolt and nut through it? It's not the "proper" way to do it, but it's a hell of a lot better than pulling the rear subframe. At that point I think you're going to end up redoing all of the suspension bits because, "while I'm in there"...

 

Haha. Exactly. Already found a subframe then came across the torsen diff with half shafts.

The local guy told me the same thing, longer bolts through the holes with a washer and nut on the back and problem solved. Drive shaft won't be here til Monday so that kind of sucks was hoping to get it and have it in this weekend.

Soon as I get the rear end sorted I'm going to really look into it dying when pushing the clutch in coming to a stop. Found a tuner an hour away so once I get the injectors and stuff in she will get dyno tuned.

 

Drive shaft arrived today. Injectors will be here Thursday. I ordered ILM comp motor mounts from FM as I can see the passenger one currently on there is broken in half. Probably where all my shudder taking off and going in reverse is coming from.

Hoping FM ships the mounts quickly so I can get all of this done over the weekend. I have an exhaust leak somewhere in the downpipe area I'd like to take care of at the the same time.

I need to change the muffler, it rattles pretty bad. Anyone have any suggestions? The car is currently straight piped into the muffler so I'd like something that isn't to obnoxious but still sounds good. And will last.

 

The classic recommendation was a magnaflow muffler. There was a specific part number but you'll have to search around to find it.

The IL mounts should make a big difference. I was in a similar boat with one of my motor mounts being a 2 piece unit and after swapping to the ILs the amount of drivetrain slop that was cleaned up was insane. First time I let off the throttle I was amazed how little the car seemed to jerk around.

 

I think I may have already mentioned it but on a Honda the first "mod" we typically do is motor mounts. I knew the Miata had stock mounts but hadn't noticed one was completely shot. I'm excited to get the new ones in there.

I will do some digging and see if I can find the magnaflow people like. I had a magnaflow on my Honda and it sounded great. The one I used on my Honda wouldn't fit on the Miata though.

 

EBC and ethanol sensor arrived today. Motor mounts will be here tomorrow along with the FF 640's. Looks like I will be able to get that stuff done over the weekend.

I think I'm going to pay someone to install and wire up the ethanol sensor and EBC, and tune it as well. Was quoted 3 hours of labor @ $135/hr for the install and $850 for a dyno tune with 91 and ethanol tables done. I could do the work myself but wiring isn't my strong suit, and it's going to need retuned anyway. I want it done correctly.

As of right now the only other things I know for sure I want to do are the exhaust and better coil overs. Oh, and I hate the extended front knuckles. Probably going to have to replace those as well. Car doesn't turn well with them.

 

The big Magaflow with the three inch inlet and outlet sounds as good as any Miata deserves to.

 

It's a little spendy but does anyone run this combo? I like a good sounding car but I'd love to be able to get my wife to actually ride in this one lol.

 

I personally have not. I believe those are both for a N/A exhaust, though. For a turbo setup, you're gonna want to run a full 3" exhaust. 2.5" at absolute minimum.

I ran a 3" Kraken exhaust on my car. The exhaust note was perfect. Quiet at cruise but it had a nice grunt when you got on throttle hard. I ran mine with the supplied resonator for over a year and then had to cut it out when I swapped to a GM differential. Didn't get noticeably louder without the resonator, so I'd probably skip that if I were to buy again.



Couple clips of the exhaust note.

 

Coming from Honda's, the first thing I googled was "3 inch exhaust for 2000 Miata" which led me to what I posted. I prefer a 3 inch exhaust because they tend to be deeper and quieter, less teenage boy. Now that I know what I'm looking for ... Thank you for commenting

Got the motor mounts in. Way easier than YouTube led me to believe it would be. Both sides done in an hour and a half. Hardest part was getting the bolts lined back up. Pretty sure these had a few more miles left on them lol

 

After I finished up I went for what was supposed to be a 5 minute drive. Ended up being an hour lol. Totally different car. Solved so many of the things I didn't like. I can actually go in reverse now so that's huge. Clutch chatter doesn't cause the whole car to shake and shudder anymore, it's pretty normal now for an aftermarket clutch. The car is overall smoother and drives 1000% better. When anyone asks me what the first mod they should do to their Miata is, I'm going to ask them about their motor mounts. No doubt.

 

For sure man, the engine mounts are the trans mounts on a miata. And partially the diff bushings. Assuming your stock mounts are in OK shape I highly recommend these diff inserts.

https://www.good-win-racing.com/Mazd...t/61-1181.html

Super easy to install and a similar jump forward to the mazcomp mounts in driveline stiffness. And not much extra NVH.

Any older car that comes into my possession always has to get "baselined" and brought up to spec, nothing comes sorted. That is a nice NB, and to be honest it can be a pain to get a turbo na/nb sorted, but once you do the driving experience is awesome. Enjoy the build!

 

After driving it tonight I'm hesitant to put the new injectors and stuff in. It runs and drives fantastic and I don't want to add anything to the equation. I've had it 2 weeks today so maybe I'll just enjoy it for a bit and see where things go. After I get the exhaust dialed of course. I'm not having any luck tracking down a Kraken 3 inch for a NB, not without buying the whole turbo kit.

 

I got the drive shaft in tonight, I don't think there was anything wrong with the one that was in it. But the new has serviceable u joints, and it did seem to get rid of some more nvh. Nothing crazy, but noticeable. With all that said, I'm still not happy with the amount of slop in the drive train on this car, especially when the clutch chatters. The new motor mounts definitely helped but I kind of wish I'd have gone with something a little stiffer, just personal preference. I don't know anything about the age of the clutch or the flywheel, but with how I have to rev it to take off I'm guessing it's a lighter than stock flywheel. The clutch works well, doesn't slip at 10lb boost so I don't really want to replace it, and with everything I've read it's pretty hit or miss if a new clutch would chatter or not. I've seen people say it both ways over the years and it doesn't really matter what brand you go with. So I guess I'll just deal with it for now. Outside of chattering when starting from a stop, the car is so much more smooth now so I guess I will just move on to the next thing.

I noticed the brake pads on the front need replaced so I'll probably throw some Hawk yellow pads on all 4. Those have been my go to for low dust but good stopping.

Injectors did arrive today but like I said in a previous post, I'm hesitant to put them on right now. The car is running great. Although if I do put them in I can probably get the car running a little leaner and get better mpg cus right now it's not doing so well in that area lol.

Still looking for an exhaust. I can't find the Kraken 3 inch outside of the full turbo kit, which I obviously don't need. I could just replace the muffler on my current exhaust but I'm pretty sure the piping is less than 2.5 inches. I have a muffler shop here in town but idk if he would do something custom for me.

 

I found the kraken exhaust, I'm not sure if it would fit with my turbo setup without modification though. It's designed to bolt directly to their dp.