Catch Can Results
- Thread starter sneakytoot
- Start date
That certainly is enough to be concerned about over a short period of time. Factor in how much more would accumulate before a recommended oil change and I'd be glad that wasn't going through my intake and collecting on my valves. Just wish someone had one for a Z06 by now.
C7Driver
In the 833 KM that I put on the car there was about 150 KM highway and the rest was city driving. There was no track time on the car and still got 1/2 ounce of oil in the catch can. So with a direct injection engine your still putting oil into the air intake from the PCV system even in normal city driving it doesn't matter if your racing or normal driving the PCV system still has to vent the crankcase. If you did a 5000 KM oil change as Wayne81 mentioned that would be about 3 ounces of oil going into the air intake thus coking the valves,
The debate rages on, my C7 has a 8 yr warranty, not worried about it. I had a Solstice with DI for 7 yrs , no issues, my son has that car now and still no issues with it. You can read page after page on the U.S forums about whether you need one or you don't. A whole lot of direct injection engines sold by GM/Ford across their fleet without catch cans and all under warranty. Their engineers must be pretty confident their setup is ok. If it works for you so be it. Here some comments from GM and Ford engineers on the matter, according to the experts it all comes down to design....from Edmunds.com
Many automakers’ gasoline DI engines do not appear to exhibit any carbon build-up issues at all, however. Digging into online threads about Cadillac’s 3.6-liter DI V6 in its popular CTS lineup does reveal some owner concerns about carbon build-up, but it’s difficult to find even a single report that any build-up has actually occurred – a record that is notable considering that Cadillac has sold more than 200,000 CTS models with DI V6s (Audi sold fewer than 2,000 RS 4s in the US during its two-year sales run).
Haider, GM’s V6 assistant chief engineer, explained how GM has designed its DI engines to combat carbon buildup: “We maintain great engine function and performance in our all our DI engines through an optimization strategy with our valve events,” he said. “Our intake-cam timing, injector targeting and timing of the injection events are optimized to avoid direct fuel contact on the intake valves. This strategy keeps smoke and soot formation to an absolute minimum, which in turn prevents excessive deposit formation.”
At the Detroit Auto Show in January, Ford was confident enough about its popular 3.5 liter EcoBoost direct-injection V6 to have technicians tear down an example engine that had accumulated the equivalent of 160,000 miles through an intentionally abusive regimen of log dragging, high-speed towing and desert racing. When they opened it up before a live audience, they found some light carbon deposits on the valves and pistons, but not enough to affect performance. In fact, the engine showed a loss of just one horsepower afterwards – roughly what Boyadjiev’s RS 4 engine lost every 500 miles.
Stephen Russ, technical leader for combustion for Ford’s 2-liter Duratec DI engine, said that similar to GM, engineers have determined the proper injection-timing calibration to help eliminate the carbon deposits. But Russ also said the technology of injection components – particularly the high-pressure solenoid injectors – has quickly matured, meaning excess valve deposits in most DI engines should become a thing of the past as these improved components are incorporated into production.
Tony Chick, principal engineer at European Performance Labs in Stratford, Connecticut, has made a career of repairing and rebuilding high-performance engines from Audi, Porsche AG and BMW, among others and his operation has garnered a reputation among car enthusiasts as a go-to place for cleaning DI engines that have become choked with carbon. Chick thinks the problem for most affected engines can be traced to the breathing system – specifically, the design of its crankcase ventilation and exhaust-gas recirculation components.
All modern gasoline engines return some crankcase and exhaust gases back through the intake manifold in order to help control emissions, but, according to Chick, some exhaust-gas recirculation designs are “dirtier" than others. Some, he said, are less-effective at preventing the passage of tiny bits of oil, carbon and other particulates that eventually get baked onto the intake ports and valves.
Chick reached his conclusion after inspecting dozens of different DI engines at his shop and finding some, like the V8 in Boyadjiev’s Audi RS 4, regularly choked with carbon while others, like the DI version of Porsche’s horizontally opposed 6-cylinder, remained much cleaner.
If he’s right, the rapid adoption of DI has actually illuminated an issue, not caused one. A “dirty” intake or exhaust-recirculation design can easily go undetected in a conventional port-injected engine due to the cleaning effect of gasoline passing over the intake valves. When the same engine designs are adapted to direct-injection fueling, however, that cleaning effect is suddenly lost – and the carbon layers can build.
There is no simple fix for engines that are prone to carbon build-up, Chick says. What’s needed is a complete redesign of the crankcase ventilation and exhaust-gas recirculation systems to prevent particulates from getting through. Fortunately, the manufacturers whose engines are frequently cited in carbon build-up reports – mainly VW, Audi and Lexus – appear to have taken this step with many of their latest models. For instance, Audi’s new 3-liter supercharged V6, used in the S4 and A6 models, has so far been free from carbon-related complaints – a far cry from the 3.2 liter V6, which has numerous threads dedicated to the condition.
If Ford and GM engineers and Chick are correct, the carbon-buildup problem now may be relegated to previous engine designs that were not well-adapted for DI. But that’s probably little consolation to some early adopters like Boyadjiev, who must add regular carbon cleaning services to their cars’ ongoing maintenance requirements – a cost that, for now at least, they are expected to absorb entirely on their own as they grapple with the “dirty” secret of this emerging technology.
Many automakers’ gasoline DI engines do not appear to exhibit any carbon build-up issues at all, however. Digging into online threads about Cadillac’s 3.6-liter DI V6 in its popular CTS lineup does reveal some owner concerns about carbon build-up, but it’s difficult to find even a single report that any build-up has actually occurred – a record that is notable considering that Cadillac has sold more than 200,000 CTS models with DI V6s (Audi sold fewer than 2,000 RS 4s in the US during its two-year sales run).
Haider, GM’s V6 assistant chief engineer, explained how GM has designed its DI engines to combat carbon buildup: “We maintain great engine function and performance in our all our DI engines through an optimization strategy with our valve events,” he said. “Our intake-cam timing, injector targeting and timing of the injection events are optimized to avoid direct fuel contact on the intake valves. This strategy keeps smoke and soot formation to an absolute minimum, which in turn prevents excessive deposit formation.”
At the Detroit Auto Show in January, Ford was confident enough about its popular 3.5 liter EcoBoost direct-injection V6 to have technicians tear down an example engine that had accumulated the equivalent of 160,000 miles through an intentionally abusive regimen of log dragging, high-speed towing and desert racing. When they opened it up before a live audience, they found some light carbon deposits on the valves and pistons, but not enough to affect performance. In fact, the engine showed a loss of just one horsepower afterwards – roughly what Boyadjiev’s RS 4 engine lost every 500 miles.
Stephen Russ, technical leader for combustion for Ford’s 2-liter Duratec DI engine, said that similar to GM, engineers have determined the proper injection-timing calibration to help eliminate the carbon deposits. But Russ also said the technology of injection components – particularly the high-pressure solenoid injectors – has quickly matured, meaning excess valve deposits in most DI engines should become a thing of the past as these improved components are incorporated into production.
Tony Chick, principal engineer at European Performance Labs in Stratford, Connecticut, has made a career of repairing and rebuilding high-performance engines from Audi, Porsche AG and BMW, among others and his operation has garnered a reputation among car enthusiasts as a go-to place for cleaning DI engines that have become choked with carbon. Chick thinks the problem for most affected engines can be traced to the breathing system – specifically, the design of its crankcase ventilation and exhaust-gas recirculation components.
All modern gasoline engines return some crankcase and exhaust gases back through the intake manifold in order to help control emissions, but, according to Chick, some exhaust-gas recirculation designs are “dirtier" than others. Some, he said, are less-effective at preventing the passage of tiny bits of oil, carbon and other particulates that eventually get baked onto the intake ports and valves.
Chick reached his conclusion after inspecting dozens of different DI engines at his shop and finding some, like the V8 in Boyadjiev’s Audi RS 4, regularly choked with carbon while others, like the DI version of Porsche’s horizontally opposed 6-cylinder, remained much cleaner.
If he’s right, the rapid adoption of DI has actually illuminated an issue, not caused one. A “dirty” intake or exhaust-recirculation design can easily go undetected in a conventional port-injected engine due to the cleaning effect of gasoline passing over the intake valves. When the same engine designs are adapted to direct-injection fueling, however, that cleaning effect is suddenly lost – and the carbon layers can build.
There is no simple fix for engines that are prone to carbon build-up, Chick says. What’s needed is a complete redesign of the crankcase ventilation and exhaust-gas recirculation systems to prevent particulates from getting through. Fortunately, the manufacturers whose engines are frequently cited in carbon build-up reports – mainly VW, Audi and Lexus – appear to have taken this step with many of their latest models. For instance, Audi’s new 3-liter supercharged V6, used in the S4 and A6 models, has so far been free from carbon-related complaints – a far cry from the 3.2 liter V6, which has numerous threads dedicated to the condition.
If Ford and GM engineers and Chick are correct, the carbon-buildup problem now may be relegated to previous engine designs that were not well-adapted for DI. But that’s probably little consolation to some early adopters like Boyadjiev, who must add regular carbon cleaning services to their cars’ ongoing maintenance requirements – a cost that, for now at least, they are expected to absorb entirely on their own as they grapple with the “dirty” secret of this emerging technology.
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The LT1 emissions/DI system is unproven from a valve deposit perspective. Who knows what will happen in 5 years plus one day.
And there are other reasons to run a catch can other than the dreaded/alleged DI intake valve deposits issue.
Catch can helps keep oil out of your intake charge, which some say may help you maintain timing under hard use. I emphasize the word "may". May be helpful esp. on track days and whatnot.
A catch can with pressure relief, like a mightymouse, may (again, emphasize "may") help alleviate crankcase pressure and leaking crank seals, which has been reported as an issue on supercharged LT1s and even some mild heads/cam and other tuned n/a C7s. May again be helpful esp. on track days and whatnot.
People can question whether the can is a good thing. But it can't be a bad thing.
And there are other reasons to run a catch can other than the dreaded/alleged DI intake valve deposits issue.
Catch can helps keep oil out of your intake charge, which some say may help you maintain timing under hard use. I emphasize the word "may". May be helpful esp. on track days and whatnot.
A catch can with pressure relief, like a mightymouse, may (again, emphasize "may") help alleviate crankcase pressure and leaking crank seals, which has been reported as an issue on supercharged LT1s and even some mild heads/cam and other tuned n/a C7s. May again be helpful esp. on track days and whatnot.
People can question whether the can is a good thing. But it can't be a bad thing.
I like the catch-can in my '06 which seems to be doing a good job. After a year I drained about an ounce of oil from it and was equally glad to not have it go into the intake.
C.
Keep in mind that GM Canada cut back on the oil change volume from 9.3L to 8.0L so the oil is no longer at the top of the dip stick - it is about 1/3 down, reducing the potential for overflow.
So the oil level should only be at the lower 3rd of the hash mark? I just added some oil this weekend (it was below the recommended hash mark) to get it to the top half of the hash mark, as per owner's manual. Is that now considered too much oil?!?
Oil when checked should be done at 175 degrees and I keep mine at the hot level on the dip stick, which is in the middle of the hash marks.
This doesn't have anything to do with a catch can between valley and intake manifold that is trying to prevent dirty side oil from entering the intake.
Also I may be wrong but I'm pretty certain oil volume was reduced by half a liter to 9.3. Did GM change this yet again?
Yes - My understanding was that 9.3 L was the Capacity to the top of the hash marks and when I took it in for the 1st oil change the dealership checked the computer and GM Canada had reduced the volume to 8 L.
I checked the dip stick when I got home, following the procedure and it was about 25% down the hash marks.
I took the throttle body apart and checked the air filter after taking delivery last fall and storing it over the winter and the filter was clean.
I checked the dip stick when I got home, following the procedure and it was about 25% down the hash marks.
I took the throttle body apart and checked the air filter after taking delivery last fall and storing it over the winter and the filter was clean.
HI All, Checked the catch can last night for the first time (Elite E2 with clean side separator ) and after about1500 km it had 1-2 tablespoons of oil in it. I put about 300 km on the car before I installed the can. There were no short trips and lots of spirited driving! I love my C7!
There's no doubt it does a job on collecting sludge......I was surprised at how much mine collected after a year of driving.
I going to check it more often now.
Thanks for the feedback.
C.
I going to check it more often now.
Thanks for the feedback.
C.
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