HFCs and Oil Consumption: FACT or FICTION
05-08-2008 | 03:27 AM
#61
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Joined: Apr 2004
Posts: 121
Likes: 1
From: Irvine, CA
Ahujadaddy sent me a PM and asked me to comment on WTF is going on here. So, here's my expert testimony to the case of HFC's and oil consumption.
In short, NO, HFC's do not contribute to oil consumption.
Tony, you are correct. A quality HFC would mitigate harmful reversion at the exhaust valve, but it this is the incorrect explanation for the question that Ahujadaddy is asking. About ring flutter and loose tolerances, I am absolutely NOT an engine builder, so I can't comment on that one.
A bit of a history which will explain all of this better. When Nissan introduced the QR25DE motor in the Sentra Spec V & the Nissan Altima (4 cyl, not the VQ35DE), the pre cats were VERY close to the exhaust ports and it seems that Nissan made them out of a substandard material. So, there were lots of Sentra's and Altimas that were burning oil like no tomorrow.
The cause? Failing cats that were powdering and scoring the cylinder walls leading to excessive oil consumption. The only way to fix this was to rebuild the shortblock, but in Nissan's case they just replaced the engines in the cars they cared to admit that there was a Nissan created problem.
The tech is just doing the good old CYA (cover your ***) for Nissan and the bad press they got from their QR25DE's.
So, if you are using a crap "high flow" catalytic converter for your car, you may be risking your cylinder walls and motor in the process. There are a few "HF"C's (I'm using "high flow" in quotes), that are using a inferior cats and calling them high flow. These are the ones that are made overseas that can powder just like the QR25DE cats were. This is precisely the reason that we ONLY use high quality Magaflow metallic cats for YOUR G37.
In short, NO, HFC's do not contribute to oil consumption.
Tony, you are correct. A quality HFC would mitigate harmful reversion at the exhaust valve, but it this is the incorrect explanation for the question that Ahujadaddy is asking. About ring flutter and loose tolerances, I am absolutely NOT an engine builder, so I can't comment on that one.
A bit of a history which will explain all of this better. When Nissan introduced the QR25DE motor in the Sentra Spec V & the Nissan Altima (4 cyl, not the VQ35DE), the pre cats were VERY close to the exhaust ports and it seems that Nissan made them out of a substandard material. So, there were lots of Sentra's and Altimas that were burning oil like no tomorrow.
The cause? Failing cats that were powdering and scoring the cylinder walls leading to excessive oil consumption. The only way to fix this was to rebuild the shortblock, but in Nissan's case they just replaced the engines in the cars they cared to admit that there was a Nissan created problem.
The tech is just doing the good old CYA (cover your ***) for Nissan and the bad press they got from their QR25DE's.
So, if you are using a crap "high flow" catalytic converter for your car, you may be risking your cylinder walls and motor in the process. There are a few "HF"C's (I'm using "high flow" in quotes), that are using a inferior cats and calling them high flow. These are the ones that are made overseas that can powder just like the QR25DE cats were. This is precisely the reason that we ONLY use high quality Magaflow metallic cats for YOUR G37.
05-09-2008 | 01:49 AM
#62
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iTrader: (2)
Joined: Oct 2007
Posts: 2,335
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From: Metro Detroit, MI [Sterling Hts.]
Just a thought - Meguiar's doesnt need plugs from individuals badly they have a built name for themselves nationally, FI on the other hand seems to be wanting to build their rep and market share up with more hunger....
Last edited by bboysteele; 05-09-2008 at 02:04 AM.
05-11-2008 | 01:26 AM
#63
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Joined: Mar 2007
Posts: 1,125
Likes: 0
From: MD & NOVA
Thanks for the detailed response from Berk as well. I think i am def leaning towards gettin some HFCs ASAP...
Joe, how about changing over to Semi Synthetic at 11,250... monitor ur oil level every week or so, and if all is well change over to fully synthetic at 15K. Something along those lines.
I'm at 18k and gonna pour in some Mobil Clean 7500 semi-synthetic, then if all is well... gonna get some GReddy 5w-30 Blue Racing Oil (yea its Group IV true synthetic) and pour it in around 20K-ish
Joe, how about changing over to Semi Synthetic at 11,250... monitor ur oil level every week or so, and if all is well change over to fully synthetic at 15K. Something along those lines.
I'm at 18k and gonna pour in some Mobil Clean 7500 semi-synthetic, then if all is well... gonna get some GReddy 5w-30 Blue Racing Oil (yea its Group IV true synthetic) and pour it in around 20K-ish
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