99 GS300 Magnaflow header/cats
03-14-13, 07:40 AM
#1
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99 GS300 Magnaflow header/cats
My GS has quite a few miles on it and has tripped the CEL lamp with catalyst eff code on bank 1. Also, the core in the cat is now rattling at higher rpm which is annoying as all getout...I ordered a magnaflow header with cats so hoping it will nuke the CEL/code and pick up a couple ponies or mpg. Here are a few shots of it prior to install. Going to take pics as I remove old one and install this and of course road test results. Wish I could dyno it before and after to see how it fares but closest dyno is over an hour away and always booked up. Also a pic of the car. Its completely stock but it wont stay that way for long.
03-20-13, 10:43 AM
#2
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Thread Starter
Well CEL lamp has been off since so guessing Im good to go. However there are a couple issues with this header that are paramount.
1. The bracket that goes from the transmission bell housing to the collector flange will not go back on. This is a problem that I will be fixing VERY QUICKLY! When in gear and stopped, AC running, and head lamps on, the exhaust makes a rattling type sound from underneath (engine at lowest stall point). With a little throttle the noise goes away but you can see the vibration in the catback pipe without the bracket installed. Im going to modify the bracket some to get it to fit like factory. It seems the collector flange is about .5" forward of where the factory one is.
2. The heater hose that comes from the back of the head (near top/back of valve cover) that makes a "loop" and then goes into the firewall sits VERY CLOSE to the #6 primary tube of the header. I took some cable ties and supported the hose up higher to keep it away from the heat. Some metallic thermal wrap may be next.
3. After running for a week or so, I can smell the "rotten egg" smell but this should go away once the cat is run for a while.
4. The lead "O" gaskets for the flanges do not fit on the collector flange very well. The hole in them is much larger than the pipe that protrudes through the flange. During install, the collector flange bolts must be snugged up a little at a time and the then gasket positioned up a little bit to get it centered before the collector bolts are tightened down all the way.
5. header will turn blue after 30 minutes of running...that sucks but oh well. Fig it would happen.
Note: after running for a week or so, I went back and snugged the flange and collector bolts up some more. I think from the expansion/contraction of hot/cold, the gaskets get a little sacked out so some "re-tightening" is needed.
1. The bracket that goes from the transmission bell housing to the collector flange will not go back on. This is a problem that I will be fixing VERY QUICKLY! When in gear and stopped, AC running, and head lamps on, the exhaust makes a rattling type sound from underneath (engine at lowest stall point). With a little throttle the noise goes away but you can see the vibration in the catback pipe without the bracket installed. Im going to modify the bracket some to get it to fit like factory. It seems the collector flange is about .5" forward of where the factory one is.
2. The heater hose that comes from the back of the head (near top/back of valve cover) that makes a "loop" and then goes into the firewall sits VERY CLOSE to the #6 primary tube of the header. I took some cable ties and supported the hose up higher to keep it away from the heat. Some metallic thermal wrap may be next.
3. After running for a week or so, I can smell the "rotten egg" smell but this should go away once the cat is run for a while.
4. The lead "O" gaskets for the flanges do not fit on the collector flange very well. The hole in them is much larger than the pipe that protrudes through the flange. During install, the collector flange bolts must be snugged up a little at a time and the then gasket positioned up a little bit to get it centered before the collector bolts are tightened down all the way.
5. header will turn blue after 30 minutes of running...that sucks but oh well. Fig it would happen.
Note: after running for a week or so, I went back and snugged the flange and collector bolts up some more. I think from the expansion/contraction of hot/cold, the gaskets get a little sacked out so some "re-tightening" is needed.
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