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Searched around. Found a photo & sum dude workin on his bud's 350z that showed this on youtube.
Wire tuckin & pulled the upper & lower collectors off. 1st of all, upper collector's got a dark orange-ish tarnish & residue on the 3 runners on driver side. Lower collector's got the same thing on passenger side. The intake manifold has got this same **** on the runner closest to the grill, then the 3rd & the 5th runner as well.
WTF is this?
Taking the manifold off tomorrow to clean these runners. Build up on the manifold is the worst, then lower & then upper, in that order, dirtiest to cleanest. Looked into each combustion chamber & they all look the same. Not too bad for 90k miles.
Anyone know & willing to share what this is all about? Looks like air might not be so evenly distributed after the t.b.?
No, not the 1st time I've realized airflow isn't equally distributed. I was just...ah...I was just testing ya'll. Yeah, that's it, just testing you & you passed! Good job bealljk!
Flow schmo, what's the deal with all 6 runners sharing the same volume in the totally open upper/lower collector assembly, yet only the driver side is dirty, which then runs down to the manifold with every other runner looking like ****?
I've seen examples that look like mine, better or worse & I've seen one that looked squeaky clean. Granted, this is after 90k miles of driving but still, clearly 3 out of six cylinders are getting cleaner air, less oil, bla bla bla. Why? How can I or can I correct this?
For sure. Planned on it before I found this. Need to make sure 90k miles is still viable for FI. Tuner to busy so I must wait a month, but when I figure it out, if it can be figured out, I will let ya'll know what I find. Bet someone out there knows what it is without doubt.
Will do Atreyu. I don't anticipate any negative results frankly. It feels stronger than ever (mods & tune) & with an issue that left visible signs, I'd think that there would be a noticeable power draw. We'll see.
Here's a photo of what the lower collector looks like from soho motorsports. The manifold was the worst. The bottom of the collector is worse than the top. Same color & same side, so I guess it's not uncommon but still, wtf?
Damnittohell. I hate when I read a thread where someones digging into something that affects me in some way and just drops the ball. This wasn't a top priority for me as I've never seen a clean lower collector, not that there isn't one, I've just haven't seen one, so I figured f'it until I stumble upon something.
I believe the staining is due to exhuast reversion. Often, I've seen it affect every other runner on the intake manifold and typically in the lower collector as seen in the photo above. Mines every other runner all leading to the passenger side cylinder head iirc. I recently saw an early G35 with the 2 runners nearest the firewall discolored. I'm learning about this phenomenon now. Apparently it has something to do with valve overlap or lack thereof, with or without excessive exhaust pressure. It can rob the engine of power and negatively affect gas mileage.
I don't plan on testing comp. or leak down at this point. I never felt there was an issue and the engine feels better than ever. What's planned no longer includes a supercharger or turbo which was the reason I wanted to do these tests, though with N20...
My 1st and only tuner told me he had big projects to wrap up. Time went buy, I emailed him a couple time and no answer. Called another shop and they told me what turned out to be a lie. They said that my tuner was going oob (out of business). I just got an email from him this Thurs and that's not the case which is great. During that time I've changed my mind back to what I was originally thinking when I 1st started modding this tank which was n/a with juice on tap. Sorry for the delay Atreyu.
Looks like this reversion may be responsible for oil consumption as well. Problems with the ceramic in the cats braking up and being sucked back in through the exhaust, intake and finally into the cylinder via reversion. This may already be known by most on the forums but it's news to me.
The only way to fix the poor intake flow issue is get a proper spaced intake mani. Aka aftermarket which allows space for all the intake runners to breath more effectively and efficiently.
Other than that I have no idea what was said or asked.
Exhaust reversion. Little if anything to do with intake flow. Valve overlap to bypass the need for an egr via manufacturer.
If you're unsure of what was said or asked, firstly, nothing was said, it was written. Here's a hint: read the thread and it's mysteries shall be revealed to you my son.
Looks like this reversion may be responsible for oil consumption as well. Problems with the ceramic in the cats braking up and being sucked back in through the exhaust, intake and finally into the cylinder via reversion. This may already be known by most on the forums but it's news to me.
Yeah, that particular oil consumption troubleshooting conclusion is the general textbook reason as to why an engine 'could' burn an excessive amount of oil. Brand new vq35de rev-ups with new cats will burn oil. That theory can change somewhat with the application.. You say that your engine runs stronger than ever with no signs of any mechanical issues despite the uneven residual, and that it's just a little dirty because of the closed pcv system.. Try getting a catch can.
Fortunately my DE never had an oil burning issue. It's an 03 built in 02 and it's been mine since day 1. Never have had an oil consumption issue at all. Some get lucky I suppose.
A catch can is a great thing for sure & I have a baffled mishimoto. Very little is caught as very little is sucked into the intake (2-3 tbspn's in 4k miles) but imo a c.c is better than venting to the atmosphere for several reasons.
The 3 shitty runners are a reversion issue which appears, at this point, to be something Nissan built into it's engines bypassing the need for an egr. The egr, as well as what's experienced via reversion are basically the same thing in that some fresh air and fuel are displaced in favor of exhaust gas which does cool down the combustion chamber, good for some, but also "regurgitates" semi-spent air and fuel. The vq series engines have acid reflux built in.
There's several ways to make this better but I'm unsure at this point if it's possible to totally eliminate the issue. It's a mileage and power killer.
Here's my main thread that has much of what I've done so far. I believe the intake mods, exhaust and advanced timing via uprev tune have probably gotten rid of most of this issue. I'm doing more up top and need to pull the intake manifold so I'll get a chance to see if things have gotten better. https://www.infinitiscene.com/thread...-redux.230572/
Here's what I thought to be an interesting read pertaining to Nissans various VQ's below. Just made it to the second page and may not read this or anything else. I don't think I'll get any further into this as I'm convinced that reversion is to blame for the discolored runners. Now I need to do what I can to combat this any more than I already unknowingly have. I think 1320 makes reversion cats to deal with this and this may be the real reason for motordynes baffled cats success? Just speculation. https://bobistheoilguy.com/forums/ub...pics/1757381/1
I had to remove the v-plenum and lower collector today. Doing some other mods in that area and I noticed something I didn't before. I took two pics, one of either side of the lower collector. When viewing these and other photo's I took today, I noticed that both sides of the intake manifold are colored the same. WTF?
It's an optical illusion. Walking from one side of the car to the other I can see now that one side of each of the 6 runners is dirty and one side of each of the 6 is clean. I still cannot explain why only the driver side bowl was discolored and not the passenger side.
I also noticed the mishimoto c.c. doesn't catch it all. I've considered adding some steel wool to grab more oil and/or using some left over lava shield to keep the c.c. cooler which should help the hot oil condense. Then again, I'm not sure that it's beneficial to prevent 100% of the oil to enter the intake.
I think Nissan as other foreign manufacturer's have a reason for this. My brand new jetta I bought 15 years ago burned 1 quart every 3k miles. VW said this was normal. I'm thinking it may have something to do with tighter tolerances, helping to lubricate the top 1/2 of the combustion chamber. One could argue that it might even be beneficial in the respect that it's having a similar effect as a wet compression test, helping to seal the rings and the worn cylinder walls and keeping compression high.
08-16-2017, 07:07 PM
3 good & 3 bad intake runners ???
