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TROYMAN |
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hey guys..
has anyone had a catalytic converter fail on regular basis in boosted application?? the first system was a 2 1/2" with a high flow cat, the cat failed after 3 months.. when i upgraded to a 3" system with what was supposed to be a high flow stainless steel metal cat. now after about 9 months i had a slight whistle over 3000rpm which i thought was just the exhaust gasses being forced out under boost..(didnt think much about it) well it got gradually worse over the last 3 months and had become a loud high pitch whistle, i thought it was a boost leak as the car was starting to lose power, after some investigating it was not a boost leak but the cat had started to collapse wedging itself in the pipe restricting the exhaust.. after further inspection i found it was not a metal cat but a ceramic one ..and being over 12 months now no waranty, so i have temperarily punched the cat out.. well what a difference in performance now. except its pretty damn loud without a proper cat.. so im going to get a new one asap.. im looking at trying one of the venom 100cpi steel cats.. i had considered the previous tune may had had some affect but it was not running dangerously lean but was having some pinging issues.. any opinions or thoughts on the cat converter situation?? anyway here is a pic.. Attachment: Attachment:
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FAST-XR |
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i had a similar problem, the core of the cat had deteriorated and come loose, it was shifting around and restricting flow. the cat was a 4.5" core 200cpi, 3" inlets. the car was tuned to 8psi, but in the end was struggling to get past 6 psi, and was the reason i was about 20kw down on the dyno day
i have now replaced it with a new 5" cat with 3" inlets 100CPI, what a difference!!!!! costed me $170 plus installation im getting it checked on the dyno at CMS today to see if the car is running safe, as the car is now making 2psi more boost than when the cat was still in good condition!!
_________________ 07 BF MKII XR6T |
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Matt_jew |
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Im thinking I also have a collapsed cat in mine.
Since my last trip to WSID where there was a bit of a pop bang during a burnout , I have had a tinny rattle under the car and I cant find it. Sounds like a heatshield rattling but they all seem to be ok. Need to jack it up on the weekend and have a look see and a bash around.
_________________ xr6turnip wrote: More people paid for a ride in a VT commodore then an AU Falcon so the VT is superior.
Based on that fact my Mum is the best around! |
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JoeXR6 |
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Age: 43 Posts: 387 Joined: 30th Nov 2007 Ride: AU111 XR6 VCT Supercharged Location: Brisbane |
Troyman, I've had exactly the same experience (but took longer to diagnose). My first cat failed and I noticed it, as it had the tinny sound described above. Replace with 3inch metal cat, which I thought would last.
Picked up car from aborted dyno tuning a year ago, to find I'd lost everything above 4500rpm, and I still had a ping despite rich tune. Also difficult starting, etc. I've just had all this stuff sorted out, and the main issue was a collapsed cat (collapsed in under 1 yr). I suspect it collapsed during the previous dyno tune. After fixing this, plus some other issues, my car has got all its power back (plus some) and revs hard to redline. Start, idle and light throttle are nice too. According to tuner it did this immediately upon clearing out the failed cat....he also attributes the excessive heat build up from blockage to the pinging I was getting. Wish i'd realised earlier! They seem pretty prone to failure. I believe the typical slight over-cranking required for an engine with aftermarket ecu contributes to cat failure, as well as the exhaust heat from boosted engines. Joe
_________________ FOR SALE! - Supercharged AUIII XR6 VCT, intercooled, T5, big brakes.... details in the 'For Sale' section - ford-parts-for-sale-f17/fs-supercharged-au-xr6-vct-series-iii-intercooled-rwc-rego-t114254.html |
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TROYMAN |
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hmm, that may be the answer and fixed the other issue i was having, it had a pinging problem at around 3000rpm which was fixed with the second dyno tune, then a month later it was starting to ping again.. on the last dyno tune alot of timing was removed about 4 deg allround to stop pinging, then yep, the last few weeks it started pinging again,...
except it always starts within a few cranks of the engine.. |
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svo_matt |
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hey troy dont have a fix for your cat problem but since it the new rage to have a stupidly loud exhaust so just keep the punched out cat on there
_________________ ..My fake plant died because I forgot to pretend to water it.. |
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TROYMAN |
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naa i want to keep it at a reasonable noise level, that way when i do open it up people dont hear it from 2 streets away
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EBXR8380 |
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This can be an issue with tune.. If too rich the fuel is burnt in cat..
The same effect if timing is too retarded.. The fix apparently is to set ECU so it varies AFR so it cools cat and gives better EPA exhaust.. Flucuating AFR from rich to lean helps cat.. At Sema there was an exhaust stand where there was two cats [Single exh to twin 2 1/4] one slightly behind the other .. Half the exhaust flow went through front cat from one pipe while the bigger rear cat flowed both front pipe 3" single so No2 could be burnt again.. So cats could run cooler with better EPA...
_________________ As in ZOOM 126 edition |
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TROYMAN |
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thanks..
what would be considered to rich?? its usually around a constant 12.5-13:1 afr except for on deceleration (fuel cut) and cruising at any speed where engine is around 2300rpm then its around 15:1 afr...so it does fluctuate a little.. i drove it tonight and i will be fitting a new cat asap due to the pungent smell from the exhaust.. |
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FAST-XR |
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i got my car dynod last night at CMS to check if it was safe, not even close to being safe, the cat was flowing that well that 8deg timing had to be removed across the whole range and extra fuel added in the bottom end
the car made the same power at the same boost as the original tune (8psi), but made over 100nm of torque low to mid range, and 50nm top end,i now hold about 900nm from 3000 to 4000 rpm, and the power curve is much fatter! car feels AWSOME! i cant imagine what another 4psi will make this car feel like!
_________________ 07 BF MKII XR6T |
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TROYMAN |
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so you had to remove timing after fixing the cat??
thats interesting, i unblocked my cat and all signs of pinging have gone!! |
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FAST-XR |
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sure did, it started pinging at 3000rpm and we decided not to finish the run for obvious reasons.
the the turbo was biulding alot more boost alot quicker, and also earlier in the rev range
_________________ 07 BF MKII XR6T |
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TROYMAN |
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FAST-XR wrote: sure did, it started pinging at 3000rpm and we decided not to finish the run for obvious reasons. the the turbo was biulding alot more boost alot quicker, and also earlier in the rev range ok that makes sense.. mine being supercharged was still making the same boost but was not getting rid of the gasses fast enough.. |
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JoeXR6 |
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Age: 43 Posts: 387 Joined: 30th Nov 2007 Ride: AU111 XR6 VCT Supercharged Location: Brisbane |
Exactly what was happening to mine troy. My tuner was surprised my car ran at all with how blocked it was.
With clear cat, intercooler, tune, etc, I can't get it to ping anywhere or under any condition. Hopefully stays this way! Might be worth talking with Venom about the cat failures you've had, and see which of theirs will be most durable.
_________________ FOR SALE! - Supercharged AUIII XR6 VCT, intercooled, T5, big brakes.... details in the 'For Sale' section - ford-parts-for-sale-f17/fs-supercharged-au-xr6-vct-series-iii-intercooled-rwc-rego-t114254.html |
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FAST-XR |
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go for a 5" 100cpi like i did, best flow you can get, i got mine for $170
_________________ 07 BF MKII XR6T |
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