Intake manifold off with pics of intake valves with deposits.

pickmeup · February 28, 2016

I know their are several write ups about using fuel that is Tier 3 certified for all GDI engines. Google it and you can find most of the reasons and questions answered. In short it has to do with intake coking . You can find the brands that are and those that are not . I wonder if a catch can and tier gas might be the way to go .

Badass69 · February 28, 2016

Fuel realistically won't make any huge difference beyond I suppose on the exhaust valve...... but that's true to any engine and not just direct injection. The intake valve is for all intents never exposed to the fuel charge as it closed whenever fuel is present in the cylinder. The oil and gases coming up from the bottom end aren't going to change much by varying gasoline brands as that is a function of good ring seal or not...... and by many of the pictures I see posted you guys have crappy ring seal based on poor break in practices that are spread by the oem in the manuals.

I just put my can on my truck yesterday and I have a tick over 15000 miles on it without touching the throttle body or the like. I had next to zero buildup on the throttle body and basically nothing for oil in the manifold either. My truck is a 6.2 so the inlet to manifold is right behind the throttle body and it was easy to see how little oil I was getting.

The problems here is just PCV gunk building up on the intake valves as no fuel is present to wash it off. The catchcan helps alleviate that.

GDI Tech · February 29, 2016

i sure would buy your expertise better if you weren't selling something here.

Take it as it is, I don't sell anything. I am only sharing technical facts. What you or any others do with it is purely a personal choice. No one should ever make a change they are not comfortable with. All of this (photo's, explanations in great detail, videos and links to actual data and not sales PR releases like the auto makers disseminate all is to help all to actually understand VS just buy because of a sales pitch.

I know their are several write ups about using fuel that is Tier 3 certified for all GDI engines. Google it and you can find most of the reasons and questions answered. In short it has to do with intake coking . You can find the brands that are and those that are not . I wonder if a catch can and tier gas might be the way to go .

You are correct, plenty of PR info out there first denying any of this exists, and then how to prevent it (even though they claim it does not exist). The facts are as no fuel touches the intake valves, it is physically impossible for ANY additive OR fuel choice to have any effect, unlike the older port injection engines that the fuel sprayed the valves cooling and cleaning them where these fuels and additives did certainly help and have benefits. This is part of the difficulty for the consumer that does not have the technical background. They will read articles and blindly believe whatever they are told. Just think about it....unless that top tier fuel, or additive you add to the fuel tank actually touches the backsides of the valves, how can it do anything? And as we for the past 6 plus years (going on 7 now) have studied all types of supposed "fixes" yet see little to no difference in most of them (I list what does help, type oil, etc.) when actually studied and compared. Until the industry is honest with the consumer (will never happen just as we will never see honest politicians either), each has to search and find this information alone with little to no guidance.

Go back and look at my credentials and qualifications. This is what I do daily. I also urge anyone that has not read it, to pick up a January issue of vette mag and read James Barry's "technically speaking" section as he covers this in detail.

Fuel realistically won't make any huge difference beyond I suppose on the exhaust valve...... but that's true to any engine and not just direct injection. The intake valve is for all intents never exposed to the fuel charge as it closed whenever fuel is present in the cylinder. The oil and gases coming up from the bottom end aren't going to change much by varying gasoline brands as that is a function of good ring seal or not...... and by many of the pictures I see posted you guys have crappy ring seal based on poor break in practices that are spread by the oem in the manuals.

I just put my can on my truck yesterday and I have a tick over 15000 miles on it without touching the throttle body or the like. I had next to zero buildup on the throttle body and basically nothing for oil in the manifold either. My truck is a 6.2 so the inlet to manifold is right behind the throttle body and it was easy to see how little oil I was getting.

The problems here is just PCV gunk building up on the intake valves as no fuel is present to wash it off. The catchcan helps alleviate that.

A lot of truth to what you state. Properly seating rings is key as well as we can see 5 different examples of the same vehicle, same fuels used, same miles and on will be far worse than another, and it is always a greater amount of blow-by due to improper break-in/ring seating. But that won't change either as 99% of new vehicle owners will follow the owners manual and that is always a gamble that they will or will not seat properly...and most will never seat as well as following the instructions the techs have available.

Good post!

glcbn · February 29, 2016

The oil and gases coming up from the bottom end aren't going to change much by varying gasoline brands as that is a function of good ring seal or not...... and by many of the pictures I see posted you guys have crappy ring seal based on poor break in practices that are spread by the oem in the manuals.

Totally agree!

Georgia1911 · February 29, 2016

... poor break in practices that are spread by the oem in the manuals...

What is the OEM's incentive to encourage poor break-in procedures?

glcbn · February 29, 2016

What is the OEM's incentive to encourage poor break-in procedures?

Not sure that they so much "encourage" poor breakin, as IMO, they don't make a big enough deal about it. The manual break in text is buried in section nine. It states:

The vehicle does not need an

elaborate break-in. But it will

perform better in the long run if

you follow these guidelines:

. Keep the vehicle speed at

88 km/h (55 mph) or less for

the first 805 km (500 mi).

. Do not drive at any one

constant speed, fast or slow,

for the first 805 km (500 mi).

Do not make full-throttle

starts. Avoid downshifting to

brake or slow the vehicle.

. Avoid making hard stops for

the first 322 km (200 mi) or

so. During this time the new

brake linings are not yet

broken in. Hard stops with

new linings can mean

premature wear and earlier

replacement. Follow this

breaking-in guideline every

time you get new brake

linings.

. Do not tow a trailer during

break-in. See Trailer Towing

on page 9-78 for the trailer

towing capabilities of the

vehicle and more information.

Following break-in, engine speed

and load can be gradually

increased.

No mention whatsoever after the engine has gone through a few heat cycles of rapid acceleration and deceleration in second gear up to about 4,000 rpm. This is what loads the rings, shaping them to the cylinder walls. They actually in so many words warn you NOT to drive it that way.

Badass69 · February 29, 2016

As said above... they don't tell you how to break an engine in at all. It's funny because if you blew your brand new trucks engine up and got a warranty replacement gm sends along specific guidelines for the tech to follow to properly break the new engine in... but when you buy the truck new no prior break in is done and you get no instructions lol.

I hooked mine onto my car hauler at the lot and towed my other truck home with it... ran it hard and let it decelerate a bunch of times with a load on it. It's no coincidence when installing my catch can at 15000 miles of me doing piles of wide open throttle as I naturally drive hard... the intake on my 6.2 was nearly dry. If you don't have lots of blow by the factory pcv system doesn't dump gallons of oil into the intake manifold.

I build engines for fun... and having a close friend that owns an engine shop I have built a lot more than just my own including a circle track team i sponsor. I just help him here and there when I am around and in turn get heavily discounted work on my own stuff. I do my own break in but it more or less mirrors what is considered the correct way to do it. Not so coincidentally, minus the odd mechanical deficiency, I don't have any problems either.

Sent from my SM-G900W8 using Tapatalk

GDI Tech · March 1, 2016

1994VMax is correct, and to go further, it is a liability issue that outweighs attempting to instruct the average consumer to follow an aggressive procedure. Think about it, can you imagine the average soccer mom or middle management man that knows nothing about how to even check their oil and other fluid levels attempting the proper instructions? The automakers have one goal, and that is to sell as many of a certain model than the competition, and competition is always fierce. Just as they do not tell the new vehicle owner to get that initial factory fill oil drained by 500-1000 miles to get out all the assembly debris and metal particles from the break-in. If Ford says "No scheduled maintenance for 10k miles!" and GM states"first oil change must be done at 1000 miles" what is the average uneducated (in automotive engineering) consumer going to pick?

Just like what octane of fuel they should use. ALL GDI engines today are 11.5:1 or higher compression ratio. With a port injection engine you would need to run race gas to avoid detonation, but as a GDI engine has no combustible fuel present during the compression stroke, detonation is greatly reduced, so these CAN run on 87....but put 93 in and not only does power output increase but fuel economy does as well. They instruct the new corvette owner to use 93 octane, yet the V6 Impala owner is told to run 87 in the owners manual even though both have the same 11.5:1 CR. It is all marketing, legal department, management that has the say over what is disseminated to the public, and the owners manual is no different. It is a guide with only some accurate direction. Most vehicle owners trade every 3 years on average and the car/truck will then be someone else's problem. Even with neglect, improper break-in, etc. most will never notice issues as they creep up by the time they trade, and when it comes to proper break-in (and there are always exceptions to any rule) those that follow the owners manual have app. a 50% chance you will have excessive oil consumption (whether noticed or not as most never check their oil...they just go in to the dealer if a CEL comes on or when the DIC prompts service is needed.

The entire sales world is full of manipulation and influencing decision making based not on actual facts, but on what the brand wants to sell.

Watch the next TV commercial carefully and see what each brand touts as the reason to buy their offering over the competitors. Always taking 1 or 2 points as being better.....ignoring the competitors area's where they mat excel. That's the sad state of making buying decisions. Finding facts and truths are difficult at best.

That is where forums like this come in as beneficial to the members. Even with so much misinformation and misconceptions, much can be learned here that otherwise would be very difficult to find.

How many would never have thought the automakers would sell vehicles with this horrible intake valve coking issue? But unless it is brought to everyone's attention, most would go through their ownership and never realize why the vehicle gradually runs worse and begins to have issues related to it. Most will trade up before it is obvious to the average driver.

Kind of like trying to determine which politician is lying the worst (as they all lie). Buyer beware has never been more relevant than now with cell phone data scanning to determine personal likes and dislikes, etc. Just as our internet searches and other activity gives data back to those that pay, selling is not on what is best for the consumer, but how well a brand can manipulate the potential buyer, and ALL automakers claim the issues are not issues. Just how many here have had oil consumption of 1 qt per 3k miles? 2k miles? 1k miles? And what did your dealer tell you? "That's acceptable".

glcbn · March 1, 2016

Well said GDI.

GDI Tech · March 2, 2016

I think we as consumers have been so conditioned to blindly follow whatever we are told that it is a shock to most that it isn't always so.

Jon A · March 2, 2016

Here is a question for you GDI Tech:

A while a go some of us noticed the stock ECM calibration on these engines dials in a bunch of cam retard in low-medium RPM low-medium throttle situations (general driving and cruising conditions). This, of course, allows for some EGR effect to take place.

We were thinking that eliminating this in the programming may improve throttle response, torque, etc, because under those conditions you want the least amount of cam retard possible for best performance. At the time I wasn't even thinking about intake valve deposits, but combustion products contacting the intake valve largely due to the EGR function is one of the things much literature blames for contributing to valve deposits on GDI engines.

For those of us who do our own tuning, would you say doing the above may be a worthwhile endeavor helping to reduce the speed at which intake valve deposits form? It's kind of a PITA because you need to re-do the entire timing map due to the increased dynamic compression in that RPM range, but it's certainly doable.

GDI Tech · March 3, 2016

Here is a question for you GDI Tech:

A while a go some of us noticed the stock ECM calibration on these engines dials in a bunch of cam retard in low-medium RPM low-medium throttle situations (general driving and cruising conditions). This, of course, allows for some EGR effect to take place.

We were thinking that eliminating this in the programming may improve throttle response, torque, etc, because under those conditions you want the least amount of cam retard possible for best performance. At the time I wasn't even thinking about intake valve deposits, but combustion products contacting the intake valve largely due to the EGR function is one of the things much literature blames for contributing to valve deposits on GDI engines.

For those of us who do our own tuning, would you say doing the above may be a worthwhile endeavor helping to reduce the speed at which intake valve deposits form? It's kind of a PITA because you need to re-do the entire timing map due to the increased dynamic compression in that RPM range, but it's certainly doable.

You are 100% correct. Many tuners are (go to HPTuners forums and read more) doing just that. And further, the FI builds are seeing this more pronounced as force feeding compounds overlap reversion.

In our studies we can attribute at least 10% of the coking deposits over time to the EGR emulation. I am not a tuner so I can't guide you on just how to optimize in the tune, but I have been following all I can find on this. Please share what you discover. Just yesterday I was having a conversation with a tuner that was trying to optimize cam timing on a twin turbo build. I will try and get more info from him as well.

Jon A · March 5, 2016

Thanks for the confirmation. Seems like it would be worthwhile. Thanks for mentioning the HPTuners forum, I hadn't been following much there for a long time.

GDI Tech · September 1, 2017

Here is some more info:

Final results of 2 year study

Here is a brief summary of what was documented in the 2 year testing by one of the Worlds largest Lubrication companies:

The XXXXXX system was tested on the most severe engine on the road toady as far as GDI related issues. The testing was performed on a fleet of new vehicles including GM and others, but they only focused on the results of the Ford Ecoboost engines as they experience the most severe GDI related effects.

First, here is how the testing was performed. Each vehicle has been run through proper break-in and driven over 10k miles to eliminate ring seating variance, etc.

Then the vehicle would be run for app 5-6k miles on their premium full synthetic oil and a sample drawn...this is without our system installed. Then, our system is installed on that same oil fill, no oil change, and then run another 4-5k miles and another sample drawn and at that time oil is drained and changed.

Here are some examples on just viscosity and fuel dilution:

Miles on vehicle: 55060 Ford 3.5L Ecoboost

Miles on oil when sample drawn: 5,943 Fuel dilution: 5.6% Viscosity @40*C: 45.71 Viscosity @100*C: 8.76 (Now, vehicle is driven and sample drawn below)

Miles on oil when sample drawn: 9,411 Fuel dilution: 3.86% Viscosity @40*C: 46.98 Viscosity @100*C: 8.82 (Even AFTER saturation well above the industry 5% threshold where oil is considered "condemned" or no longer able to protect the engine our system was able to not only prevent further fuel dilution and viscosity degradation, but actually IMPROVED each taking the oil that was no longer usable and extending it's ability to protect far longer.

Now, that was the least dramatic result....some were as high as fuel dilution levels of 7% to above 12% by 5k miles (cold start enrichment in cool/cold conditions adds to dilution far quicker) and we were able to bring those levels down even more dramatically, in some cases by as much as 50% less after a few thousand miles WITH our system installed.

Other benefits documented: Average fuel economy increases of 1-3 MPG due to a cleaner burn with the contaminants removed from the PCV vapors as more energy is released with just air and fuel present during the combustion process. This also shows a significant reduction in knock retard as pre-ignition is reduced and combined with a cleaner burn in the combustion chamber, reduces emissions as well as improves fuel economy.

As our system converts the PCV system to full time evacuation and flushing VS part time as the OEM systems come and retains a closed emissions compliant system.

This prevents the stagnant periods of operation when the contaminants and combustion by-products that enter as blow-by and are the primary source of oil contamination and our system greatly reduces this by removing these at all times the engine is running utilizing 2 separate evacuation suction sources, the intake manifold vacuum for when reversion pluses are not canceling it out (during acceleration or hard operation no evacuation suction is present stock), and using the Venturi effect when accelerating or running high RPM/throttle.

On GDI engines (most all Automakers are now 100% GDI) we have the additional benefit of reducing the intake valve coking issue by as much as 85% (we cannot eliminate all as these engines use variable valve events to allow back filling of exhaust gasses back into the port behind the valves to be re-burnt emulating the outdated EGR system/valves of old.

To summarize, the benefits:

Engine life extended to 2-3 times expected life w.out the system installed.

Fuel economy increase of 1-3 MPG average.

Extended oil drain intervals allowing from 50% to 100% longer use of oil reducing pollution from improperly disposed of drain oil.

Reduced tailpipe emissions. As we remove most of the compounds causing a incomplete burn in the combustion process reducing the amount of emissions.

Reduction of intake valve deposits by as much as 85%.

The downside is these MUST be drained and the contents collected disposed of properly as with any drain oil. every 5k miles as a rule (will vary from engine to engine depending on state of piston ring seal to cylinder walls).

We do have a system that never needs to be emptied or service for in excess of 100k miles, but not released yet that could be retrofitted at a later date.

What is in the contents of the system that are removed from the engine crankcase vapors?

Here is a sample after a 2400 mile drain after being spun in a centrifuge to separate all for analysis:

70% was acidic water (the sulfuric acid produced during the combustion process cannot be separated from the water).

23% was raw fuel (GDI engines introduce fuel at well over 2,000 PSI and this pushes many times the amount past the rings of old port injection systems that operated at 45-50%)

and only 7% was actual oil, and it is saturated with abrasive particulate matter.

This other wise would have remained in the crankcase mixing with and contaminating the engine oil, and also contaminating the intake air charge reducing the over efficiency of the engines combustion process.

On Fleet applications, depending on miles driven the fuel economy and oil drain extensions give a ROI in app 6.7 months average. As a whole, these could drastically reduce overall emissions as well as tremendous savings on fuel cost and usage.

And one of the other major causes of failure:

An Introduction to How Low Speed Pre Ignition Affects Engine Components

Paper #:

2017-01-1042

Published:

2017-03-28

DOI:

10.4271/2017-01-1042

Citation:

Passow, E., Sethi, P., Maschewske, M., Bieneman, J. et al., "An Introduction to How Low Speed Pre Ignition Affects Engine Components," SAE Technical Paper 2017-01-1042, 2017, doi:10.4271/2017-01-1042.

Download Citation

Author(s):

Affiliated:

Pages:

4

Abstract:

Current market demands in conjunction with increasingly stringent emission legislation have vehicle manufactures striving to improve fuel economy and reduce CO2 emissions. One way to meet these demands is through engine downsizing. Engine downsizing allows for reduced pumping and frictional losses. To maintain acceptable drivability and further increase efficiency, power density increase through the addition of boosting is employed. Furthermore, efficiencies have been realized through the use of high gear count transmissions, providing an opportunity for manufactures to effectively down speed the engine whilst still achieving the desired drivability characteristics. As a result of these efficiency improvements, gasoline turbo charged direct injected (GTDI) engines are developed for and tend to operate in low engine speed, high torque conditions . This operating condition results in an environment within the combustion chamber which has the propensity to experience a disruptive abnormal combustion event known as low speed pre-ignition (LSPI). This phenomenon has the potential to catastrophically damage the power cylinder unit (PCU); therefore, engine manufacturers and suppliers are working to eliminate LSPI or design components to survive LSPI events if they occur.This paper is the first of a series of papers that will discuss MAHLE’s LSPI research, focused on power cylinder unit (PCU) components and systems designed to withstand LSPI events, as well as minimizing or eliminating the propensity of LSPI to occur.

A truly effective system such as the Elite E2-X or similar internal design (Genuine RX from TeamRXP.com, etc.) provides full time evacuation as described in the study.

Lot's of data out there VS the sales pitches from those just selling products and not working directly with the industry on all of this.

boombalatty · September 1, 2017

So serious but likely dumb question:

Earlier in the thread it was stated that no catch can, regardless of manufacturer will catch all of the unwanted vapors that pass through it - what if you ran two catch cans in series? Would there be a performance impact? Would the second catch can actually catch anything? I'm not purposefully looking to burn money, but if two is appreciably better than just the one .. well I can probably justify it to my live-in accountant.