04 MSM - big rattle under car

Check the heat shield around the catalytic converter. They can loosen up in one spot and rattle like mad.

JoeTR6 wrote: Check the heat shield around the catalytic converter. They can loosen up in one spot and rattle like mad.

Is that the front silver one? Attaches via four 10mm bolts?

Actually, I was thinking of the shield crimped/spot welded around the cat. I've had that come loose on an older Miata producing a load metallic noise at certain RPMs. If the rattle doesn't seem related to RPMs, that's probably not it.

Well update.

I took the trans shield thing off. Still rattles like crazy. The exhaust wasnt clearing that shield very well. Need to work on clearancing it and put it back on. The FM exhaust is still tight but doesnt clear the shield well.

If i hit or kick the driver's front wheel there's a rattle there. The rotor dust shield thing seems like it could be loose but being that it's press fit, i can't see any way to tighten it.

Really frustrating to deal with in 108 degree heat and completely ruining the enjoyment of the car. Rattles and runs like E36 M3. Got smoked by a non-turbo Elantra today and the berkeleying thing wont idle worth a berkeley. I'm pretty sure the Cherokee is faster than this berkeleying thing.

Shoulda bought an s2k

Serious now, have you checked your control arm bolts on the front? I had a slight rattle in the s2000 last week and it turned out the upper contol arm bolts were just loose enough for the arm to move like .5mm. It took me a while to find it too. Just an idea.

Spoolpigeon wrote: Shoulda bought an s2k Serious now, have you checked your control arm bolts on the front? I had a slight rattle in the s2000 last week and it turned out the upper contol arm bolts were just loose enough for the arm to move like .5mm. It took me a while to find it too. Just an idea.

Nope i haven't but i'll definitely put that on the list to check tomorrow when i likely tear the entire front end of the car apart in a fit of rage.

And yes. I should have bought an S2000. Serious thinking will be occurring once i get the car sorted. (Rattle, rebuild shifter, get it tuned again.)

Cool. If you want to take mine for a real test drive, you're more than welcome to codrive it at an event 8)

Have you checked that the cat itself isn't clogged? I can see where that might make noise, and if it's particularly plugged up, affect how the thing runs.

peter wrote: Have you checked that the cat itself isn't clogged? I can see where that might make noise, and if it's particularly plugged up, affect how the thing runs.

It's only rattling when i hit a bump, particularly with driver's front tire. Definite metal on metal "clanging."

Cat is fine. I haven't checked it, but it's definitely not why the car runs like crap.

Spoolpigeon wrote: Cool. If you want to take mine for a real test drive, you're more than welcome to codrive it at an event 8)

I've driven a few, but i appreciate the offer. My Miata is just a street car, no competition.

Thats right, I forgot that your escort is the race car and your turbo miata is the daily. Just ponder that statement for a minute :D

In somewhat related news, how is the racecort coming along?

Spoolpigeon wrote: Thats right, I forgot that your escort is the race car and your turbo miata is the daily. Just ponder that statement for a minute :D In somewhat related news, how is the racecort coming along?

No no no... MX6 is the daily. Turbo Miata is a street "toy" only. The MSM isn't competitive in anything anyways.

I never claimed to be smart!

The cat makes a pretty low rattle that could sound like metal on metal when the ceramics come loose and don't blow out downstream. Tap on it with a rubber hammer and see if it rattles. With all the extra fuel you're probably running I wouldnt be surprised if its gone bad

I've hit the cat with a hammer, no rattles. Rattle is most prevalent when the driver front wheel hits something.

Good point on the fuel though. Car needs to be tuned again before i do destroy a cat. Black smokes pretty bad.

Damn money pit piece of E36 M3.

Fixed it. Pics to follow when i get home.

92CelicaHalfTrac wrote: Fixed it. Pics to follow when i get home.

Thats all we get?! What a tease.....

Spoolpigeon wrote:

92CelicaHalfTrac wrote: Fixed it. Pics to follow when i get home.

Thats all we get?! What a tease.....

I'm still trying to figure out what to make of it. What was rattling doesn't seem like something that should have fallen off the newest and lowest miles car i own. I also have no idea how to put it back on.

And i'm a bit depressed right now. There's no reason a car that dyno'd 245whp on FM's dyno should be getting WASTED on some onramp fun by a stock NC with an exhaust. (Sooo... my car is slower than stock?)

This car sucks. I can't wait until the new wheel/tire package is on the MX6 so i can start driving it again.

Anyways, this is what it was. Some part on the back side (closest to rear of car) of the rotor shield thing. Looks like it was spot welded originally to the shield?

I don't know... is this important at all?

Blergh.

It looks like a dust sheild of some sort. Not sure if it's really important or not though. I'm sure you could spot weld it back into place.

And I've always wondered about the MSM cars feeling slower than they should be. A local racer here has one with quite a few things done to it, yet it doesn't feel much faster than it did stock. Maybe its the baby dick turbo? Too short of gearing maybe? I dunno.

Mine is stock and I've never had problems keeping up with NC's or any other Miatas. The gearing is terrible however.

Not sure what that piece is or why it fell off. I will take a look at mine though. I know it is not off since I have no rattles, but it can't hurt to look at it.

I could spot weld it back on, but i'd have to take the hub off to do it, and that's kinda... MEH at the moment for me.

TJ, i know it needs a tune, and i'm really just hoping that's all the issue is. I don't think it's any faster than the Cherokee, though.

Steve, mine has an upgraded turbo. What i don't understand is that people with these cars making 270whp trap around 115mph. I don't think i'd even break 100mph, and there's no way i should be that far off. Crossing my fingers it's a bad tune.

Well a E36 M3 tune would be my guess as well. Especially since you mentioned it smoking a few posts ago.

How could the factory tune a car badly? Wouldn't they all go out the same?

Mazdax605 wrote: How could the factory tune a car badly? Wouldn't they all go out the same?

The factory tune on these was garbage, big bogging issues, terrible boost response, bad AFRs, etc...

This isn't a factory tune. My car has a Flyin' Miata "Big Enchilada" with an upgraded turbo and a Hydra Nemesis.