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FREAKING Downpipe keeps getting loose

2K views 21 replies 12 participants last post by  MtFujiSupra 
#1 ·
Hello my fellow supra brothers.

So this has been driving me nuts for the past year or two now, and I can't seem to pinpoint the problem.

I bought a catless DP from someone here on the forums, and after installing it, everything seemed fine. Fitment was good, and there were no exhaust leaks. Then, after about a month, i started to hear rattling noises down by the connection between the DP and the turbo housing.

Just recently, I replaced my catless DP with the Stock toyota DP for obvious reasons. :) .

The rattling noise was completely gone, and it has been about two weeks now...but the noise is back again. It just feels like the downpipe is coming loose right where it connects to the turbo housing. It is producing this annoying rattling noise.

The mechanic whom I give my car to says he torques the three bolts on the turbo housing to 50ftlbs... I can't think of any other solution. Do any of you guys use some kind of a high temp gasket sealant? Should I get some fresh gaskets/bolts?

Thanks in advance for all your help.

Samira R
 
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#2 ·
Since you can install a OE cat I'll assume you are still on stock twins. The gaskets for the OE cat and a aftermarket DP are totally different. You ask about bolts so I'm confused what you really have- stock is three studs in the EGCV log and three sloted hex castle nuts are used.
 
#4 ·
MtFujiSupra said:
Since you can install a OE cat I'll assume you are still on stock twins. The gaskets for the OE cat and a aftermarket DP are totally different. You ask about bolts so I'm confused what you really have- stock is three studs in the EGCV log and three sloted hex castle nuts are used.

Sorry for the confusion.

I am on stock twins...and I guess i'm not too knowledgeable about the terminology here.

Three studs and three slotted hex castle nuts would be correct.
 
#6 ·
I am using the stabilizer bracket with my stock toyota DP. However, this bracket cannot be used with an aftermarket dp (as you probably know)...so I didn't use it while my car was catless.

Any more ideas?
thanks for the input...
 
#7 ·
TS1 said:
I am using the stabilizer bracket with my stock toyota DP. However, this bracket cannot be used with an aftermarket dp (as you probably know)...so I didn't use it while my car was catless.

Any more ideas?
thanks for the input...
You could have a flange welded onto the aftermarket dp for the stabilizer bracket.

It's possible that one of your studs is stripped. Fwiw, I'd suggest getting all 3 studs and nuts replaced with brand-new oem studs & nuts from 'yota.
 
#8 ·
The ceramic butterfly valve in the EGCV is famous for rattling.
 
#17 ·
I don't think you ever said if the nuts were actually LOOSE when you (or your mechanic) checked them. I seriously wonder if the nuts are actually coming loose. LOL They are more likely to be on so tight that they twist off when you're trying to remove them than they are to come loose on their own (assuming the are the correct OEM studs and nuts). I'd be looking at the valve or something else that might be causing the rattle.
 
#19 · (Edited)
supralover93 said:
try the lock washer with new studs and nuts (if they are stripped) and see what happens. i wouldn't replace the studs if i didn't have to because there is a good chance that they will break.
Lock washers won't work because of the high heat ... oem crown nuts work perfectly without lock washers.

As I said above, imo 3 new studs and 3 new nuts from Toyota is the most likely way to solve the problem as you've described it. If you'd like to take this remote troubleshooting a step further, remove the studs and nuts, and post close-up high-res pictures of them.
 
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