Help tracking a metallic rattle... - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to   Members

General Miata Chat A place to talk about anything Miata

LinkBack Thread Tools
Old 04-22-2008, 10:14 PM   #1
Senior Member
Thread Starter
Join Date: Dec 2004
Posts: 1,450
Total Cats: -1
Default Help tracking a metallic rattle...

Was hoping you all could help me brainstorm to figure out where/how to look for this metallic rattle I've been experiencing for a couple years now. It appears to happen in the 3000-3500 RPM range, is loudest on engine braking in gear, but seems to also happen during accel. So anytime there's load, I guess.

This rattle has persisted through a new clutch/pp/flywheel install, a swap to a '99 transmission, and upgrade to the 1.8L driveshaft and differential.

So far, the only thing I've tried is tapping around the tranny/PPF (because that's where it sounds like it's coming from, especially with the inner shift boot removed!) area with a rubber mallet, and the only thing I noticed was the speedometer cable seemed to rattle a bit, but it's not really a metallic noise. I tie-wrapped it in a different position for the hell of it, but it didn't make a difference.

My exhaust is all home-brew from when I put the turbo on the car a few years ago, but it seems to have enough clearance in all directions, and the stock heatshields have long since been removed. Plus, if the exhaust were rubbing, it would be more of a constant drone/buzz/rattle that likely got louder with RPM, whereas this seems to happen in a window of RPM.

Any thoughts or ideas?
bripab007 is offline   Reply With Quote
Old 04-22-2008, 10:57 PM   #2
Elite Member
iTrader: (3)
Join Date: May 2006
Location: Houston, TX
Posts: 2,900
Total Cats: 0

flapper valve rattling on the exhaust housing... tighten down your wastegate rod a bit and see if that helps. I had the same problem for a while.
Arkmage is offline   Reply With Quote
Old 04-23-2008, 12:39 PM   #3
Senior Member
Thread Starter
Join Date: Dec 2004
Posts: 1,450
Total Cats: -1

Hmmm, that's an interesting theory. I don't have a threaded wastegate rod, but I could try shimming it I suppose.

Last I checked, though, it felt pretty tightly-seated at rest.
bripab007 is offline   Reply With Quote
Old 04-23-2008, 12:41 PM   #4
Supporting Vendor
iTrader: (33)
Ben's Avatar
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99

+1 on the WG rod/linkage thingy. Mine used to do that.
Ben is offline   Reply With Quote
Old 04-23-2008, 12:42 PM   #5
Elite Member
iTrader: (13)
cjernigan's Avatar
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,147
Total Cats: 6

Exhaust hitting the rear axle?
cjernigan is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
1991 special edition with hard top full part out JC, NJ russian Miata parts for sale/trade 6 10-08-2015 04:01 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 01:45 AM
WTB HPDE miata - Texas Voltwings Cars for sale/trade 0 09-27-2015 07:40 PM

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 02:43 AM.