Troubleshooting: Glowing DP
 

So I have a log manifold, SR20 t25, and a 3" exhaust w/ cat. Heres the issue:

I picked up my car from the shop and it had a very weird metallic rattle (much like pinging) coming from the exhaust. I pulled over and I noticed the downpipe was glowing for about 4" where it attaches to the turbo. Let me tell you what I have diagnosed so far.

It is not detonation (the sound is localized) to the turbo/DP
The turbo compressor side spins freely with no signs of hitting
My AFR is not off, and neither is my timing.

Has anyone had something like this happen? I want to say it is a clogged cat, however, the cat is fairly new, but it is a cheap one.

Re: Troubleshooting: Glowing DP
 

clogged cat, to thin of tube used for downpipe, extremely high EGT's due to ---- tune

Re: Troubleshooting: Glowing DP
 

+1

Re: Troubleshooting: Glowing DP
 

Tune is fine.. downpipe has been working for quite awhile.. guess clogged cat it is

Re: Troubleshooting: Glowing DP
 

Like this ;D
http://www.rbracing-rsr.com/turbo/waterturbo.jpg

Re: Troubleshooting: Glowing DP
 

Rofl, no my turbo wasnt glowing :) Great pic though!

Re: Troubleshooting: Glowing DP
 

Easiest way to check for a clogged cat is to let the car warm up and place your hand behind the exhuast. Clogged cats tend to super-heat the exhaust gas as it passes. Normal exhaust gas temp at the tail pipe shouldn't be to hot, one with a clogged cat will damn near give you a burn.

Re: Troubleshooting: Glowing DP
 

good call... i'll jump on that after work today.

Re: Troubleshooting: Glowing DP
 

what kind of piping was used to make the exhaust?

Re: Troubleshooting: Glowing DP
 

too much powar :S

Re: Troubleshooting: Glowing DP
 

The exhaust is 3" turbo back with a flex section and a cat. Its pretty damn free flowing, so it supports the "damn cat" theory.

Looks like this:

http://www.shoremotorsports.com/pics...strearview.jpg

Re: Troubleshooting: Glowing DP
 

how old is they exhaust? if the cat is 3" as well, event he cheap ones, shouldnt be clogged.

i am leaning towards the idea that its something else.

what tune do you have? Injectors? Fuel pump? FPR? Ignition?

if its not the tune, then i would think the fuel/ignition area for a weak link.

Re: Troubleshooting: Glowing DP
 

Are you sure you aren't running lean?

I mean I know you said it isn't the A/F, but are you sure?

Re: Troubleshooting: Glowing DP
 

The exhaust is several months old and has been running great up to this point.

The setup:
t25 from SR20, Megasquirt.. 550cc injectors 195hp pump with coil on plug setup. Again, this issue is not pinging from the motor. My cruise AFR is between 13.5 and 14.2ish on the AEM wideband, so it is even a little rich. Under boost it runs between 11.3-12 Its been too damn cold to work on the car the last few days, but I'm almost through pulling the turbo. I want to check that the turbine side wheel isn't jacked up. I also have a GT2871 to swap onto it so it serves a dual purpose. I ordered a magnaflow metal core woven cat to replace my ebay junker should I need to.

For the record: this is the cat that is in question
http://cgi.ebay.com/ebaymotors/3-Met...spagenameZWDVW

Re: Troubleshooting: Glowing DP
 

His timing map (built motor):

http://www.boostedmiata.com/timing/pnpdefaults.jpg


My timing map (stock block):


http://www.boostedmiata.com/timing/newtiming1.jpg


It wasn't his tune....running fine for months until he got it painted....it's either the cat or the turbines are fubaredddddd.

Re: Troubleshooting: Glowing DP
 

so what did the painters do to your car?
makes me think of...

http://img225.imageshack.us/img225/4...yoff273mp0.jpg

Re: Troubleshooting: Glowing DP
 

Is it running red after no-boost cruise?
Is the manifold itself or exhaust side of the turbine red? Check in dim light.

I agree with the cat theory, if it's the downpipe...

Otherwise, I'd look for a timing screw up - low timing = high EGTs. Make sure MS is still commanding the right timing and your base timing matches what you see with the timing light.