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I'll bring over the info from other members already posted showing illustrations and we can discuss this engine and the improvements over the Gen 4, and the LT 1 (truck V8's fall into this as well as they share the beefier block, etc.)

I want to go into the new super charger and how GM was able to split the inter cooler into two bricks and place them at the sides of the screw housing to gain hood room....really like it.

Anyway, there is an excellent article in the Dec 2014 issue of Hot Rod on the new LT 5 and quoting GM engineers, and this I did not expect...as far as I know, GM is the first major automaker (I may be mistaken, but I follow this close and it's the first I recall) to openly disclose the issue with intake valve coking, the causes, and how they are dealing with it. The LT 4 has gone a few steps further than the first Gen 5 and as far as I can see have maxed out the oil separation ability before they are also trapping and returning the damaging compounds that must be evacuated and removed to not cause engine damage. That falls into the 20-25% range which is BETTER than most catch cans.

Hats off to the GM leash holders allowing the engineers being straight on this!! And as many that have read and followed my threads and posts on this over the years, this may sound like a broken record. But it is not from me....it is from GM themselves.

Please read:


just got the Dec, 2014 issue of Hot Rod, please copy Rick and Co. on this. They are discussing the brand new 650 HP LT5 engine for the new Z06, and for the first time, GM engineers admit to the issue I have identified in these direct injection engines, and what they are doping to address it. Just like a presentation from me:

According to John Rydzewski, assistant cief engineer fro small block v8's

" One issue that faced engineers was equalizing the pressure across different parts of the crankcase. The Gen 5 block has bulkhead breathing cavities just above the cross-bolts on the nodular iron main caps to allow air to circulate between cylinder banks, yet that proved to be insufficient on the LT4. Because all oil drain-back feeds through the center of the block, differences in crankcase pressure can prevent oil from draining properly, causing the PCV to suck up oil rather than crankcase gasses. "Its critical that we get oil out of the valley", says Allen \Rice, the design engineer responsible for ventilation and lubrication. The solution was simple: Two holes, roughly 5/8 inch in diameter, were drilled into each lifter valley. A PCV separator, which is unique to the LT4, was developed to keep oily air from being drawn through the intake, where it could end up collecting on the back of the intake valves. A little bit of oil on a port injected engine can help lubricate valves, but because all Gen % V8's are direct injected, there's no fuel washing the back of the intake valve. That means oil in the PCV system can end up sticking to the back of the hot valves impeding airflow and eventually preventing the valves from seating properly.
 

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Tracy, thanks for starting the dicussion with great information. As I am getting a LT4, am glad that GM Powertrain made some changes to specifically address some of your concerns, i.e., it is clear from your comments, and those of key GMPowertrain staff, that they have at least started down that road. For those who have not seen the article in December Hot Rod, here it is (with thanks to Hot Rod magazine).

The 2015 Corvette Z06?s LT4 V8 All Pages
 

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This thread is a continuation, in this proper area, of one started by "Redc7"(thank you) on a GM LT4 presentation. To keep continuity, I am now reproducing here key comments/pictures (some by screen print, some direct quotes), here.


Slide # 21 of above GM LT4 presentation:


And, finally, Tracy's post:

"You are correct Rodney (rdslon01). The "vent" tank/lines are a great addition. It is not a oil separating system though, but will work to reduce or eliminate the "burping" which the GM dry sumps have needed since the C6 Z06. It will work on the order of a "anti hammer" tank on a plumbing system and give the tank the ability to "absorb" the pressure spikes w/out pushing the oil out the clean side. "

If I missed or mis-spoke anyone's comments, please so note. Just wanted to bring previous key elements of this issue, previously on another thread, all focused into this key location, e.g., Tuner Boost's thread.
Thank you all, in advance, for continuing this important discussion here.
 

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This is some incredibly valuable information in understanding the new supercharged direct injected 650 HP LT4 engine. This information also restores my faith in GM and the Corvette team in addressing an issue that has become a deep concern to me personally. I have to admit, over the decades I never dealt with direct fuel injection, therefore was never confronted with any of the problems connected therewith. So this represents a learning experience for me. I was however able to recognize the validity to what Tracy (Tuner Boost) was trying to convey in his earliest posts, which he ran into a great deal of resistance on. It's great to see GM's Engineering Staff are working on and addressing the exact same problem.

I never really saw a clear picture of the piston and connecting rod assembly for the LT4 before this Hot Rod Magazine article. Although I haven't seen any numbers yet on the connecting rod lengths and stroke of the engine, the pistons appear to be very short with the pin located just below the oil ring receiver groove and displaying a slipper skirt design, which provides for a very light combination, thus reducing the reciprocating weight substantially. Needless to say, I'm pretty stoked about this new small block engine GM has come out with. Thank you Tracy and thank you John for this great thread.
 

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Great info, thanks!

One correction to the above it says "They are discussing the brand new 650 HP LT5 engine for the new Z06" shouldn't that read "They are discussing the brand new 650 HP LT4 engine for the new Z06"?
 

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Great information! Gen V LT4...it's all good!

So, Tuner Boost, now that GM has installed a separator that is BETTER than most catch cans, what is your recommendation for pending LT4 owners? Run them hard and enjoy the fruits of GM engine engineers labor? Or, does the RX can still have a future in that engine?
 

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This thread is a continuation, in this proper area, of one started by "Redc7"(thank you) on a GM LT4 presentation. To keep continuity, I am now reproducing here key comments/pictures (some by screen print, some direct quotes), here.


Slide # 21 of above GM LT4 presentation:


And, finally, Tracy's post:

"You are correct Rodney (rdslon01). The "vent" tank/lines are a great addition. It is not a oil separating system though, but will work to reduce or eliminate the "burping" which the GM dry sumps have needed since the C6 Z06. It will work on the order of a "anti hammer" tank on a plumbing system and give the tank the ability to "absorb" the pressure spikes w/out pushing the oil out the clean side. "

If I missed or mis-spoke anyone's comments, please so note. Just wanted to bring previous key elements of this issue, previously on another thread, all focused into this key location, e.g., Tuner Boost's thread.
Thank you all, in advance, for continuing this important discussion here.
Excellent elegant! This goes into pretty great detail, and what I see is similar to what we were putting into our race engines costing $20-$30-$50k plus 15 years ago or so, and to see GM using the same materials and processes is impressive as heck in a production car. These engines could go 1/2 million miles or more cared for....they have addressed the weak and problem areas we have complained about over the years in the previous generations of the LS based family. Look at the piston tops and the design to control the flame front for as even of a burn from the center out. In our race engines we index the plugs with spacers so when tight the open gap between the electrode and strap point toward the center of the piston/combustion chamber to try and accomplish similar. The oil squirters are in all gen 5 engines where in the past only the L4 and V6 DI's had them. The weak points in the crank shaft have been addressed, and on and on. This engine is every bit what a all out competition engine was 10-15 years ago. What was leading edge then in racing were seeing in even the truck versions of the Gen5.

Lot's more I want to go into on these...excellent discussion.

This is some incredibly valuable information in understanding the new supercharged direct injected 650 HP LT4 engine. This information also restores my faith in GM and the Corvette team in addressing an issue that has become a deep concern to me personally. I have to admit, over the decades I never dealt with direct fuel injection, therefore was never confronted with any of the problems connected therewith. So this represents a learning experience for me. I was however able to recognize the validity to what Tracy (Tuner Boost) was trying to convey in his earliest posts, which he ran into a great deal of resistance on. It's great to see GM's Engineering Staff are working on and addressing the exact same problem.

I never really saw a clear picture of the piston and connecting rod assembly for the LT4 before this Hot Rod Magazine article. Although I haven't seen any numbers yet on the connecting rod lengths and stroke of the engine, the pistons appear to be very short with the pin located just below the oil ring receiver groove and displaying a slipper skirt design, which provides for a very light combination, thus reducing the reciprocating weight substantially. Needless to say, I'm pretty stoked about this new small block engine GM has come out with. Thank you Tracy and thank you John for this great thread.
Yes, they have done an amazing job here addressing so many things you don't see in a production engine. The early aftermarket cams have had 4 lobes ground in for greater fueling, I was surprised to see that can result in issues over how they do the 3 lobe. Either way, there is plenty of fuel available in the LT 1, and now with the LT 4 having substantially greater capacity above the LT 1, let the tuners loose!

Great info, thanks!

One correction to the above it says "They are discussing the brand new 650 HP LT5 engine for the new Z06" shouldn't that read "They are discussing the brand new 650 HP LT4 engine for the new Z06"?
Correct. I was on late last night and probably have a few other typo's. Thx!

Great information! Gen V LT4...it's all good!

So, Tuner Boost, now that GM has installed a separator that is BETTER than most catch cans, what is your recommendation for pending LT4 owners? Run them hard and enjoy the fruits of GM engine engineers labor? Or, does the RX can still have a future in that engine?
They will still need a robust aftermarket solution as 20-205% effectiveness is the threshold where you also begin to trap and retain the damaging compounds the PCV system must remove to not sacrifice engine life and cause accelerated wear like the vented cans that defeat the PCV's functions do (seeing far to many of them on builds....the owners have no idea how critical it is to not sacrifice their engines by installing those types).

There are only a few catch cans that catch 80% plus of the oil and contaminates. The RX at the top (still none have equaled it in the independent testing) at 95-98%, and the Elite E2 is right up there as well as the SMC.

I also noted they are using a simple type of (using this loosely) centrifuge like the industrial separators do which is a plus as well. So they have taken this further than any other maker aside from the new Lamborghini's system I have seen to date.

Any system that returns the oil to the crankcase will hit the limitation of also trapping and returning the damaging contaminates at that 20-25% effectiveness....but I am willing to bet the "burping" issue will be a thing of the past, or nearly so with the new sump tank expansion addition. That is a biggie. But with ID, ALL oil must be stopped, and that can only be accomplished with a add on unit that does not return the mix to the crankcase. The barrier here is the end user. Most will NOT accept the added step of emptying a system like ours and the couple others that work well require.

We are stepping up our tier one solution that needs no emptying for the average life of the car, but we are still a year or more out (could be longer with the PEA hurdles) before we are ready with it. In the mean time, it is good to know there are some proven solutions out there now. Add the RX system with the new improvements and you will see the best to date IMHO.

Also, looking at the powdered metal rods they are using attest to the strength. I wonder on the rod bolts, which in the past have been a weak point when we pushed over 600 or so HP as the stock units would stretch and cause failures. ARP 2000's correct that.

More discussions to come.
 

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Yes Tracy, the powdered metal rods.... The mere term scared the crap out of me the first time I heard it. Forged steel sounds much stronger and I went with a set of $1,400. Crower Billet rods built to my specifications for the engine I built for the Cobra. I gather the powdered metal rods in the LT4 have gone though a more thorough machining process, plus I noticed they bushed the small end on them. As far as the bolts are concerned, even the bolts they used on the LS7 were from what I understand junk in the they had no memory, so once stretched, they were throw aways and needed to be replaced anytime the engine was pulled down.

I'm not planning on doing anything with the Z06, seeing as how I'm more into floating in the pool with a Margarita in my hand these days, but I sure hope the rod bolts aren't going to be a concern should I decide to buss the Z06 up to 6500 from time to time....
 

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Yes they are as they should be at almost $200. a piece. They're pretty over the top as far as steel rods go. LOL
Only the hard-core of us can look at internal engine parts and droll over them....were a goofy bunch to the outside world!

On to the article. Read over several times on the 8 speed auto, and again, impressed to the max. They really went outside the standards to accomplish more durability and less parasitic loss....that trans will hold 700 hp as it comes! And the new internal design changes again show the skill these engineers have.
 

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Can't tell you how impressed I am with GM's Engineering Staff right now. These are some very exciting times. During my racing career I never tried to reinvent the wheel, but rather attempt to enhance or take various design features several steps beyond the original form by attempting to understand the concepts the original engineers had in mind. In doing so, many of the modifications made were successful in my research and development projects. Although it required an understanding on my part of what the engineers were trying to accomplish. This is why I was never tied down to any one particular make or manufacturer. I took design concepts from all of them and incorporated those into one. So, it was never all GM, Ford and Mopar, but a combination of all three.

As far as I'm concerned, I'm inspired with what I'm seeing on the part of GM's Engineering Staff in that it appears they are watching, listening and combining different concepts to improve the end result, thinking outside the box of their own organization. I understand the major manufacturers have been working with the aftermarket for a number of years now, but it seems like it's more prevalent now than ever. Indeed, these are some very exciting times.....
 

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Saw, the new Z06 A8 is rated to 738 HP, the Z06 7-speed similarly.

Tracy, based on what you know at this point, and as this is your section, please what specific RX product(s) would you recommend for the LT4. (Understand that as more info comes out, you might change your recommendation(s) in the future.). Thank you.
 

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Saw, the new Z06 A8 is rated to 738 HP, the Z06 7-speed similarly.

Tracy, based on what you know at this point, and as this is your section, please what specific RX product(s) would you recommend for the LT4. (Understand that as more info comes out, you might change your recommendation(s) in the future.). Thank you.
Sure John,

The Dual valve can is still a must due to the PCV system still relying on intake manifold vacuum for all evacuation, so anytime your over say 2/3rds throttle (cam profile will make this vary for the aftermarket cam guy's) there is no vacuum present in the IM, so thats when pressure will still build and seek the path of least resistance, bringing vapors with some oil mist in through the cleanside. Having the dual valve so the evac suction switches to pre throttle body where 6-9" of vac is present at that time allows the flow to remain clean in, foul out. The cleanside separator is always a good idea, but how critical it will be (a must now) we will know after we have a few Z06's to test on. The real test will be to see if the RX system still traps a good amount of oil after the enhancements of the LT 4. I applaud the changes they have made, all will reduce the oil ingestion rate, but with direct injection, you want no oil and gunk making contact with the valves. And as we have seen in the past, 20-25% is the threshold before the damaging compounds that need to be evacuated are also trapped and retained in the oil, and that is why a system that does not return what is trapped is the only way to date that all the oil can be stopped.

What they have done as far as I can estimate, is greatly or near completely eliminated the big "burping" we have seen with the dry-sumps to date, and that includes the C6 dry sump engines as well.

So, as soon as one of the customers takes delivery and installs the RX system, I'm guessing and estimating at this point. Anxious to see. The real win would be nothing caught in the RX system with the new LT 4, but that I can guarantee won't happen (strong claim, but we do these for Fords to Ferrari's, and even the new Lambo system allows app 70-80% through). Either way, these are awesome improvements...haven't been this excited in ages!

And the A8, I would not hesitate to bolt 800 HP to one as from the 4L60E on, they have rated power lower than they can really handle. Amazing trans. Cant wait until GM offers it as a "connect and cruise" option. Were doing a LS swap in a pro-street 57 Chevy right now and that would be perfect for it!
 

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As you're aware Tracy, I've got your dual valve can and separator on my self right now, so as soon as I take delivery of my Z06, it'll be installed with only 20 miles on the engine. Whatever is on the odometer plus the ride home from the dealership (Est. 10-15 miles). I'll contact you for instructions for testing at that time. Now the wait......
 

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We are offering FREE installation and inspection of the intake system while the customer waits so all can be documented with video....so anyone with a new Z06, call and set up a time for some great education.

941-721-1826
 

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Hey! Not to get off topic here, but I heard somewhere RX might be making a change to their clean side separator that may very well be a game changer. Stay tuned for any updates from RX and Tuner Boost.....
 
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