ahh prolly a post cat sensor screaming for attention.

 

Dude - look at my mods consumption is expected

 

ok - seriously :

YES - I had consumption when my spacer went in - then I resolved a bad plenum gasket and it went away.

Leaks kill these cars in many ways - vacuum is key.

 

YEA...WHERE"S MY CAT!!!!!

 

labree or fast intentions.......both yield great gains

 

The discussion continues! Thanks for the heads up Noah. Noah (Foo_G) and a couple of us have continued talking about this issue in another thread.

Good to hear that you guys are still looking into this too.

You mean past the rings?

It is a dilly, that's for sure. I tend to think that it's something we haven't thought of yet... some relationship that we don't understand.

It would be interesting to hook Noah's ScanTool up and see what we could find out.

It would be interesting to put a set of non-foulers on and see if that helped. Especially after your observations about the non-foulers.

This is the first time I have heard of this. This was not on Ben's car because he doesn't have non-foulers (unless he got them since Saturday's Meet).

I wonder what would happen if you plugged the o2 sensor hole in the test pipe and taped the sensor up under the car (rendering it inoperative). Maybe make sure that the sensor gets fresh air to breathe.

My thoughts are that you don't want to adjust anything in a racing engine based on exhaust measurements. Who cares what the exhaust contains, it's going out of the car. This discussion is for off-road use, as are the test pipes.

But oil burned up by the Cat would still exit the tailpipe.

 

OK - I'm not going to quote the last one:

Oil wouldn't come though - the CAT burns way to hot - almost zero residue left over.

The race cars have devices/systems that create negative pressures/vacuum in the systems to compensate for this exact sort of thing. We were discussing it the other night.

I don't want to lead too much into this right now - we're still researching these possibilities ourselves.

Taping up the O2 sensor is just going to foul condition it and CEL the ECU. If it were truly an off road situation, we'd not care about the CEL, as the computer wouldn't even be there - another one would be and the system would handle itself accordingly.

There is a fine line in these cars now...the technology may be getting to a point where we all can break it with simple mods and changes at certain points - damn..did I just say that??? SHAME on me...

When you hear of lots of FI cars breaking weeks after builds, or that the bottom ends need strengthening - it gets you wondering why - then things like this happen and maybe these things are going unnoticed and causing issues nobody is seeing until it's too late and you'll never know.

I hate it when you get those things that make you go hhhmmmmmm

Rick

 

Exactly. I used to use a system first designed by Bill Jenkins. An angled pipe welded into the header collector is connected to the valve covers with tubing. The exhaust gases pass by the venturi and create suction on the pipe. That vacuum creates a negative pressure in the crankcase and theoretically makes the pistons go up and down easier. It's actually a bit more complicated than that, but you get the drift.

That's what originally made me think that the increased flow of the test pipes could be creating a vacumm beyond the combustion chamber that might draw the oil past the rings or valve seals. I would be surprised if this was the case, however.

I meant completely remove the o2 sensor, plug up the test pipe hole, and tape (attach) the o2 sensor to the bottom off the car. The o2 sensor would be open to the clear, clean air and not see any of the gas that passes from the test pipes.

You said installing non-foulers cut down oil use by one half. If that's true, I'd try the next step which would be to completely remove the o2 sensors from the exhaust. The race car only statement was sort of a disclaimer.

Absolutely agree here.

 

Removing the O2 sensor and just taping it to the bottom of the car will cause a CEL. If it doesn't sense gases, it will CEL. When it does, the computer mods the car to accommodate and other things go awry.

I can't at all explain why the oil consumption went down once the foulers were in place. I put them there to stop the CEL...not just to put them in place...so the CEL stopping was the key to that find.

Also - YES and NO - the off road use only is much of a disclaimer, but if you really realize the impact - and what we are seeing - makes sense huh

High quality Carb and EPA approved CATS are the next step....

Rick

 

is this consumption on +05 6MTs?

6MT has a different ECU/PCM as well as Variable Valve on the Exhaust Side.. Also the 02 Sensors are wideband or "A&F Sensors" for the Computer

Have you tried using a standalone system and see if there is still a consumption problem? Maybe the Computers doing something to try to "Fix" or compensate for something and its causing an oil consumption problem.

just some food for thought

 

Issue is on both AT and MT - 05 and up - I have not heard of any previous years having issue.

We're not doing extensive testing on this - just researching mildly for potential prescriptive countermeasure opportunities.

Rick

 

Alright I have Strup Test pipes and started burning oil... I mean leaking like a stuck pig. I would burn over 1 litre in 250-300kms. Anyways, I took the test pipes off and the MREV intake and took it into Infiniti. Well they checked the PCV valve, EGR, compression test(stupid since compression ring will not affect oil control), blah blah. Long story short all that stuff was good, exactly what we told them. However, even with the stock cats back on the car is still going through oil. I have nearly burnt 2 litres in 1000km, I am doing the oil consumption test for infiniti. To me the problem seems to be an oil control ring since the car would puff under acceleration... leading to a collapsed or broke oil control ring. If the car was puffing all the time it would be a bad valve seal. So that is my information to add to the topic.

To be totally honest it sounds like infiniti is having issues with their engine. There is no way even with the mods the person listed above that in 6000km you should consume more then 0.5 litres of oil, maybe a litre tops(motor only holds 4.5 litres. My brother runs a 470rwhp Cobra(supercharged) around with long tubes, no cats and straight through muffler(zero backpressure) and doesn't use a drop of oil and that car is driven way harder then mine. The locally dealership had mentioned they were having issues with FX45's burning/using oil, but my G35 was the first G35 with an issue of oil burning.

I don't know, but it sounds to me like infiniti ****ed up something in the 05+ engines. I don't think the test pipes are the sole cause of the problem... they simple cause the problem to show itself.

 

ho many miles/kms do you have on your G?

I have just over 15k miles on mine and no oil issues yet... knock on wood.

 

I have an 04 6mt.My car burns oil.It just dissapears.I know i am short a quart to 1.5 quarts at about 3000 miles.I have 45000 mostly hwy.I talked to the dealer they say m35 and m45 burn oil also.The only mods i have are y pipe ,k+n drop in and z tube.

 

I agree with Serrengetisandg that the test pipes are only showing the problem because the cats are not burning off the oil.

I would like to know how all of these engines with consumption issues were broken in from new. The biggest issue for any oil consumption is ring sealing.
Of course the seating of the compression rings is the single most important thng in a breakin. Infiniti is telling everyone to take it easy on break-in, which is quite honestly a bad idea. You should not be running the thing to redline but you should not be easy on it.
When you hone the cylinder you are creating a cross-hatch pattern to allow oil to be held on the cylinder wall for lubrication. The ill effect of honing the cylinder is the creation of peaks and valleys from the cutting action. The peaks are the issue here. On initial break-in it is the rings job to remove the peaks from the cylinder as cleanly as possible. The best way to accomplish this is to achieve as much ring to wall pressure as possible. If you are not aware the pressure in the cylinder is what pushes the ring out against the wall. FI cars are much easier to break-in because you have added pressure to the cylinder on top of the static pressure. Load on the engine is the only way to increase this pressure.

With that said, I am sure Infiniti is using Diamond hones and not conventional stones when they build the engine as is many manufactuers now. One thing diamond stones do is leave more peak metal on the cylinder wall and I doubt Infiniti is brushing or plateau honing the cylinders after initial honing. This means there is more metal to be removed by the rings then a conventional honing and therefore more ring pressure is going to improve the removal process. Lighter pressure will only smooth the metal over onto the cylinder wall which is what ruins the cylinder wall condition. Having this overly smooth condition does not allow the oil control rings to do thier job. Remember the oil control rings are low tension rings so you want the flatest possible surface on the cylinder wall to be scraped. What happens in the rolled over peaks condition is the oil control ring does not stay out against the wall and it constantly hitting "speedbumps" which push the ring a way from the wall.
In General this will not damage the ring but will affect the edges of the ring over time and only make the problem worse.

There has always been the debate on the internet on break-in procedure. The side that says to not take it easy never bother to explain the reasons and maybe they don't know why and it's just what they heard. There is good cause for this theory.

To be honest, I haven't had a car that burns the kind of oil you guys talk about but I am also not easy on a car. I know in all the time I worked in the dealership many of the customers who would complain of oil consumpion were the type who probably never took there car near redline. The one customer I had who was Autocrossing his car regularly never complained of these issues and to be honest his engine was strong in comparison to many of the other cars drove.