Hi Octane fuel and Effects on Aftermarket Exhaust Systems
#17
05-12-2009, 07:15 PM
Going back to check the pump is a good idea. You might have mixed up the leaded/unleaded gasolines or it is possible the track mixed them up when filling the tanks. Lead irreversibly fouls the cats preventing the intended chemical reactions and sometimes even causing decreased flow. Lots of us run 100 octane unleaded without issue.
#19
05-12-2009, 07:45 PM
Stating the brand of exhaust you own might allow others to chime in with options. I believe Fabspeed is the only modular exhaust and all of the others will probably require you cut out the old cats and weld new ones in. As suggested earlier, that would be a lot cheaper than a whole new exhaust. You might have better luck at a local independent shop or at one of the tuners near where you live rather than the dealer.
I recently ran across the quote," Porsche, the gift that keeps on taking." I think it fits for most of us.
I recently ran across the quote," Porsche, the gift that keeps on taking." I think it fits for most of us.
#21
05-12-2009, 09:05 PM
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#24
05-12-2009, 11:12 PM
Lead and Manganese (MMT) are the two most common cat killers. They coat the reactive surfaces in the converter, destroying them.
The only cure is a replacement.
IMHO, someone caused one of these two agents to be introduced into your fuel tank. A little Sherlock Holmes work and maybe a chemical test will find the culprit.
The only cure is a replacement.
IMHO, someone caused one of these two agents to be introduced into your fuel tank. A little Sherlock Holmes work and maybe a chemical test will find the culprit.
#25
05-12-2009, 11:31 PM
If you were referring to my car, I have the Cargraphics Loud exhaust with the black Fabspeed tips, which I believe are exactly the same as the EVO tips. The tips will fit just about any exhaust.
#26
05-13-2009, 06:42 AM
After driving it for a bit were the exhaust tips a bit white, a little chalky maybe? If so the gas was leaded. This isn't usually an issue for the O2s as they can clean themselves if not poisoned repeatedly but for a catalytic it can be fatal.
If it wasn't lead it's remotely possible that the ECU mapping wasn't adjusted for the octane and that the timing wasn't advanced enough. higher octane burns more slowly and if too little timing is onboard you'll still have a reaction going in the cylinder when the exhaust valve opens - the exhaust overheats and can also trash the catalytic. This would be pretty rare though IMO, I'm betting it was leaded and if you saw a chalky residue on your exhaust you'll know for sure.
If it wasn't lead it's remotely possible that the ECU mapping wasn't adjusted for the octane and that the timing wasn't advanced enough. higher octane burns more slowly and if too little timing is onboard you'll still have a reaction going in the cylinder when the exhaust valve opens - the exhaust overheats and can also trash the catalytic. This would be pretty rare though IMO, I'm betting it was leaded and if you saw a chalky residue on your exhaust you'll know for sure.
Last edited by BLKMGK; 05-13-2009 at 06:47 AM.
#27
05-13-2009, 07:45 AM
lol - I got it. Plus a GIAC ecu upgrade.
"997 TT, with about 10K miles on it with 100 cell cats and GIAC ECU, nothing but perfect<!-- google_ad_section_end --> "<!-- / message --><!-- sig -->
"997 TT, with about 10K miles on it with 100 cell cats and GIAC ECU, nothing but perfect<!-- google_ad_section_end --> "<!-- / message --><!-- sig -->
#28
05-13-2009, 07:51 AM
Join Date: Jun 2007
Location: Northern Virginia
Posts: 82
Rep Power: 21
perfect call
Your are Right on the Money yes I did see the white chalk and I have determined that It was 110 octane Leaded fuel Mt fault at the track!
What's the best fix?
I'm getting P0420 error
Has this damaged the lamda sensors? I'd
I have been told that the ecu can be programed to defeat the ox sensor fault
Or replace the exhaust system $4000
What do you think?
What's the best fix?
I'm getting P0420 error
Has this damaged the lamda sensors? I'd
I have been told that the ecu can be programed to defeat the ox sensor fault
Or replace the exhaust system $4000
What do you think?
After driving it for a bit were the exhaust tips a bit white, a little chalky maybe? If so the gas was leaded. This isn't usually an issue for the O2s as they can clean themselves if not poisoned repeatedly but for a catalytic it can be fatal.
If it wasn't lead it's remotely possible that the ECU mapping wasn't adjusted for the octane and that the timing wasn't advanced enough. higher octane burns more slowly and if too little timing is onboard you'll still have a reaction going in the cylinder when the exhaust valve opens - the exhaust overheats and can also trash the catalytic. This would be pretty rare though IMO, I'm betting it was leaded and if you saw a chalky residue on your exhaust you'll know for sure.
If it wasn't lead it's remotely possible that the ECU mapping wasn't adjusted for the octane and that the timing wasn't advanced enough. higher octane burns more slowly and if too little timing is onboard you'll still have a reaction going in the cylinder when the exhaust valve opens - the exhaust overheats and can also trash the catalytic. This would be pretty rare though IMO, I'm betting it was leaded and if you saw a chalky residue on your exhaust you'll know for sure.
#29
05-13-2009, 08:07 AM
The cats are likely toast, the O2s can often survive a little lead, especially when run on regular gas afterwards. Sadly I think the catalytics will not come back - sorry about that 