LT1 forced induction
01-01-2013, 01:13 AM
#21
Le Mans Master
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New, cam-driven fuel pump: The direct injection system features a very-high-pressure fuel pump, which delivers up to 15Mpa (150 bar).
It took a little while to find this, and you may have to go back a few pages to get a better idea of the context, but this is basically it:
http://ls1tech.com/forums/16947735-post348.html
From this page:
http://ls1tech.com/forums/generation...-block-18.html
Now, I know this is a page where a lot of the information "Bigg_Gunz" is giving is *possibly* false information, but a few of the builders on there believe he's at least knowledgeable enough to be creditable at this point.
Of course, I could be totally wrong and GM does something unexpected and gives us no wiggle room to do mods. I doubt that, though. I'm quite sure that there's PLENTY of room in this motor's tuning so that GM can bolt on a blower without any added cost to the motor and ECM. Less different part numbers = less cost.
1000 HP on stock DI? Wish that to be true but why would the engineers design that robust? Sorry not likely. The big issue will be injector timing and aftermarket injectors. Look at large tuners for 997.1 vrs 997.2
personally until these issues are hammered out fi will be out unless your OK with a hacked additional Injection or alky Injection.
personally until these issues are hammered out fi will be out unless your OK with a hacked additional Injection or alky Injection.
Also, they're using this same engine for forced induction, so it has to be ready to make a LOT more power. It's not like any motor GM has ever produced was out of fuel for upgrades stock. Every motor they've came out with had injectors big enough to add power without replacing the injectors. There needs to be wiggle room for bolt-ons. Period.
01-01-2013, 09:39 AM
#22
Le Mans Master
Of course, I could be totally wrong and GM does something unexpected and gives us no wiggle room to do mods. I doubt that, though. I'm quite sure that there's PLENTY of room in this motor's tuning so that GM can bolt on a blower without any added cost to the motor and ECM. Less different part numbers = less cost.
Because they're not allowing anyone to mod the fuel tables. This engine is basically going to be a bolt-on motor. Based on the fact that it has so many sensors (including EGT sensors), it should be able to self tune for just about anything.
Also, they're using this same engine for forced induction, so it has to be ready to make a LOT more power. It's not like any motor GM has ever produced was out of fuel for upgrades stock. Every motor they've came out with had injectors big enough to add power without replacing the injectors. There needs to be wiggle room for bolt-ons. Period.
Let me fist say i HOPE I am wrong but there alot of assumptions in the above statements.
Who even has an ECU to hack yet? How do we know that fuel tables cannot be hacked? If fuel tables cannot be editted then how can 1000hp be possible? There are no aftermarket DI injectors available.
So every motor GM came out with had big enough injecocts to add power? So with 2006 and later C6 we can just bolt on a blower and go? We know the answer.
Self tuning isnt the end all of tuning. That doesnt mean that bolt on a blower and let ecu do its thing. How do we even know that itll be in closed loop during PE?
01-01-2013, 11:39 AM
#23
as an aside.
cobb tuning has already cracked the ford focus ST ECU. which has DI and a turbo. the car has only been out since the fall i think.
so as an example, it may be possible to quickly crack the new vette ECU once it becomes available.
though i dont keep up with every car out there, many cars have had ECUs initially considered impossible to crack, the Nissan GTR is probably the best example, only to be cracked eventually.
there are simply too many aftermarket vendors for corvettes for GM to decide to make it impossible to crack the ECU but only time will tell.
the carbon build up on the valves is a well known issue with DI and i've yet to hear of a solid fix for it though some sort up upstream injection would seem to be the answer.
cobb tuning has already cracked the ford focus ST ECU. which has DI and a turbo. the car has only been out since the fall i think.
so as an example, it may be possible to quickly crack the new vette ECU once it becomes available.
though i dont keep up with every car out there, many cars have had ECUs initially considered impossible to crack, the Nissan GTR is probably the best example, only to be cracked eventually.
there are simply too many aftermarket vendors for corvettes for GM to decide to make it impossible to crack the ECU but only time will tell.
the carbon build up on the valves is a well known issue with DI and i've yet to hear of a solid fix for it though some sort up upstream injection would seem to be the answer.
01-01-2013, 12:27 PM
#24
Race Director
GM is utilizing a new, propritary PCV system that we have yet to see any details on. It is the reason for the funky looking humps on the valve covors we first noticed ~6mos ago when pics of the truck version were released. I have no clue yet as to how it works, but it's supposed to greatly reduce the amount of carbon build-up in the intake tract.
01-01-2013, 06:27 PM
#25
Le Mans Master
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Let me fist say i HOPE I am wrong but there alot of assumptions in the above statements.
Who even has an ECU to hack yet? How do we know that fuel tables cannot be hacked? If fuel tables cannot be editted then how can 1000hp be possible? There are no aftermarket DI injectors available.
So every motor GM came out with had big enough injecocts to add power? So with 2006 and later C6 we can just bolt on a blower and go? We know the answer.
Self tuning isnt the end all of tuning. That doesnt mean that bolt on a blower and let ecu do its thing. How do we even know that itll be in closed loop during PE?
Who even has an ECU to hack yet? How do we know that fuel tables cannot be hacked? If fuel tables cannot be editted then how can 1000hp be possible? There are no aftermarket DI injectors available.
So every motor GM came out with had big enough injecocts to add power? So with 2006 and later C6 we can just bolt on a blower and go? We know the answer.
Self tuning isnt the end all of tuning. That doesnt mean that bolt on a blower and let ecu do its thing. How do we even know that itll be in closed loop during PE?
) but I recall the injectors on the DI ecotecs being able to make 500HP without new injectors... That's a big increase over their stock 260HP. (Almost double)
01-02-2013, 08:16 AM
#26
From GM's LT1 press release:
Many engine builders on LS1Tech have already pointed out that this is enough to push more than 1000 BHP.
It took a little while to find this, and you may have to go back a few pages to get a better idea of the context, but this is basically it:
http://ls1tech.com/forums/16947735-post348.html
From this page:
http://ls1tech.com/forums/generation...-block-18.html
New, cam-driven fuel pump: The direct injection system features a very-high-pressure fuel pump, which delivers up to 15Mpa (150 bar).
It took a little while to find this, and you may have to go back a few pages to get a better idea of the context, but this is basically it:
http://ls1tech.com/forums/16947735-post348.html
From this page:
http://ls1tech.com/forums/generation...-block-18.html
One of your links also talked about the tri-lobe fuel pump drive:
It works so well there are no measureable forces, It's like it not even there. Now thats engineering!
01-02-2013, 10:47 AM
#27
The 6.2L DI engine will be a bust...way too complex...trying to do too much with an antiquated format....DOHC 4.5L supercharged would be just fine...develop more horsepower and .....lighter....not as complex with the cylinder deactivation, high pressure injectors and pump...change has got to come or it won't last....
Last edited by sampaschal; 01-02-2013 at 10:48 AM. Reason: corrected spelling...
01-02-2013, 11:43 AM
#28
Le Mans Master
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The 6.2L DI engine will be a bust...way too complex...trying to do too much with an antiquated format....DOHC 4.5L supercharged would be just fine...develop more horsepower and .....lighter....not as complex with the cylinder deactivation, high pressure injectors and pump...change has got to come or it won't last....
The LT1 appears to be far less complex, and lower parts count than a supercharged 4.5L DOHC V8. Or were you thinking of a two cylinder?
01-02-2013, 02:10 PM
#29
Color me skeptical on the "1000hp capable" OEM fuel system here. Just because the STATIC flow rate of the new DI injectors looks very big at a glance doesn't mean you can deliver that to the cylinders. Remember that a DI system can NOT inject fuel during the power and exhaust strokes. Basically, you end up with about 1/4 of the original injection window that you used to have (time wise) on a port fuel system. Most DI injection actually happens on the intake stroke because we know that it still takes some amount of time for the liquid fuel being injected to actually evaporate and mix with the air charge in the cylinder prior to ignition. This is not a stratified charge DI system (like some European DI engines), so allowing time to evaporate and mix until close to homogenous distribution has been achieved is required for both emissions and power. BTDT. 
The biggest hope for the aftermarket would be for GM to have some high output (supercharged?) version up their sleeve where the parts required to make bigger power (injectors, pump) may become shelf items for those looking to "roll their own."
The biggest hope for the aftermarket would be for GM to have some high output (supercharged?) version up their sleeve where the parts required to make bigger power (injectors, pump) may become shelf items for those looking to "roll their own."
01-02-2013, 02:13 PM
#30
The pressure calculations determine the possible flow through the injector, the fuel pump volume output in GPM determines the HP capacity. The fuel pump is a positive displacement pump and if its volume is not sufficient, it doesn't matter how much the injector is capable of flowing at a given pressure. Once the fuel pump is maxxed out, HP is maxxed out. The fuel pump may indeed have the capacity to support 1000 HP on gasoline (seriously doubt it on E85) but nobody has stated its capacity, only the pressure at the injector. Until we see the capacity, nobody can state with certainty how much HP is capable.
One of your links also talked about the tri-lobe fuel pump drive:
No measurable forces??? BS! That's like saying it's a perpetual motion machine which we all know defies the First Law of Thermodynamics. Pressure is developed by the pump, a lot of pressure...there has to be some forces somewhere.
One of your links also talked about the tri-lobe fuel pump drive:
No measurable forces??? BS! That's like saying it's a perpetual motion machine which we all know defies the First Law of Thermodynamics. Pressure is developed by the pump, a lot of pressure...there has to be some forces somewhere.
The injectors, which feature 6 holes each and specially designed injector spray and droplet patterns, have a flow rate of 125.7 lbs/hr at 1,450 psi, and can be fed up to 2,175 psi from the 1.48 cc/rev geometric displacement fuel pump.
01-02-2013, 04:25 PM
#31
All I've been able to find about the pump is:
The injectors, which feature 6 holes each and specially designed injector spray and droplet patterns, have a flow rate of 125.7 lbs/hr at 1,450 psi, and can be fed up to 2,175 psi from the 1.48 cc/rev geometric displacement fuel pump.
01-02-2013, 07:07 PM
#32
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St. Jude Donor '13
No auto manufacturer domestic or import will release a total solution as it is to costly, and it requires the extra step of emptying a proper separator. The Alfa Laval units used on industrial diesles on locomotives and freighters uses a multi step centrfuge style filtration system so the oil can be returned to the crankcase, but the lowest cost is over $6-8k and up from there. If you return it like some unknowledgable catchcan manufacturers do, then your returning the damaging combustion byproducts in concentrate to the crankcase and the motor will wear prematurely.
The engineers at all auto manufactures have had robust solutions for years, but marketing, legal, accounting/budget, and the brass have nixed all due to added cost and the fact that marketing studies show nearly all buyers will NOT accept an additional maintanance step (heck, most dont even open the hood to check oil between changes, and how long has it been since any manufacturer included a trans fluid dip stick?). The only way is to stop and trap it all before it enters the intake air charge, and almost no "oil catchcans" catch more than 40-70% of the oil present in the crankcase evac vapors. (the RX can is guaranteed to, but look at the internal design and see all the steps the crankcase vapors go through in the RX cans and you can see why so few work well. ALL catch oil, even a beer can, but only a few brands actually catch 80% or more).
Currently most all pretend it is not an issue and when the customer complains about lost power and fuel economy they sell a throttle body cleaning and upper induction treatment that helps, but is temporary and the lossened hard deposits cause verticl scouring on the piston skirts. So aside from a robust aftermarket solution, dont expect much more than what you see on the newer LSA motors addressing the cleanside only (responsible for only a few percent of the ingestion).
None I have seen. You can find animated video on the internet that makes it appear they do, but none actually do that I have seen to date.
We use the OEM stock injectors on the high HP builds on these and the Mazda & Subaru builds we do...but we always use a modified HPDI pump for the extra fuel delivery.
On the 3.6 v6 GM DI motors we use a progressive methanol injection system and run 100% meth to supplement the fuel above 9-10# of boost (have pushed it to just under 700hp with C16 in the tank, but that wont work on the street). We also do standalone systems where we add an injector rail to the intake manifold and tap into the primary pump (on the camaros & caddilacs we use the ZL1 or CTS-V lift pump) and pull signal from the current coil paks and injectors...but that is a pricey solution and not practical at this time.
Yes, we have not seen a limit on the current DI injectors to date, just the HPDI pump limiting.....but we have yet to tear into a LT1 as none have been released that we are aware of.
What we have had is regional GM rep bring in this past summer (unannounced....no call ahead of time) to have our system installed on both a new 1500 series truck and a 2012 LFX DI camaro, but no official contact (we share data with GM/Ford/Chrysler engineers we have met over the years and they share off the record info back, but nothing official or sanctioned to be released).
Chrysler has resisted going to DI but they will have to follow, and look at the difficulty in cracking the PCM/ECU on the 2011 & 2012 hemi's. (standalone systems are still our best solution when building big boosted late model hemis).
The real hurdle here with DI is marketing demographics. Accurate info will rarely be released pertaining to the intake valve "gunking/coking" issue just as it has been suppressed to date by all the early DI manufacturers. Officially none acknowledge there is an issue, and that wont change IMHO.
The engineers at all auto manufactures have had robust solutions for years, but marketing, legal, accounting/budget, and the brass have nixed all due to added cost and the fact that marketing studies show nearly all buyers will NOT accept an additional maintanance step (heck, most dont even open the hood to check oil between changes, and how long has it been since any manufacturer included a trans fluid dip stick?). The only way is to stop and trap it all before it enters the intake air charge, and almost no "oil catchcans" catch more than 40-70% of the oil present in the crankcase evac vapors. (the RX can is guaranteed to, but look at the internal design and see all the steps the crankcase vapors go through in the RX cans and you can see why so few work well. ALL catch oil, even a beer can, but only a few brands actually catch 80% or more).
Currently most all pretend it is not an issue and when the customer complains about lost power and fuel economy they sell a throttle body cleaning and upper induction treatment that helps, but is temporary and the lossened hard deposits cause verticl scouring on the piston skirts. So aside from a robust aftermarket solution, dont expect much more than what you see on the newer LSA motors addressing the cleanside only (responsible for only a few percent of the ingestion).
Well, the direct injection ecotech motors didn't need injector upgrades at all to make a lot more power. I can't seem to find the articles I'd read before, and the ecopower forums are down () but I recall the injectors on the DI ecotecs being able to make 500HP without new injectors... That's a big increase over their stock 260HP. (Almost double)
) but I recall the injectors on the DI ecotecs being able to make 500HP without new injectors... That's a big increase over their stock 260HP. (Almost double)On the 3.6 v6 GM DI motors we use a progressive methanol injection system and run 100% meth to supplement the fuel above 9-10# of boost (have pushed it to just under 700hp with C16 in the tank, but that wont work on the street). We also do standalone systems where we add an injector rail to the intake manifold and tap into the primary pump (on the camaros & caddilacs we use the ZL1 or CTS-V lift pump) and pull signal from the current coil paks and injectors...but that is a pricey solution and not practical at this time.
Nice, I found the same info with a search. Assuming the fuel pump turns at the same RPM as the camshaft (a big assumption given the tri-lobe drive) and peak power happens at 6000 RPM, 1.48 cc/rev translates into ~266 L/hr. Assuming a BSFC of .45 lb/HP-hr, it takes ~276 L/hr to make 1000 HP on gasoline (not E85)...pretty close.
What we have had is regional GM rep bring in this past summer (unannounced....no call ahead of time) to have our system installed on both a new 1500 series truck and a 2012 LFX DI camaro, but no official contact (we share data with GM/Ford/Chrysler engineers we have met over the years and they share off the record info back, but nothing official or sanctioned to be released).
Chrysler has resisted going to DI but they will have to follow, and look at the difficulty in cracking the PCM/ECU on the 2011 & 2012 hemi's. (standalone systems are still our best solution when building big boosted late model hemis).
The real hurdle here with DI is marketing demographics. Accurate info will rarely be released pertaining to the intake valve "gunking/coking" issue just as it has been suppressed to date by all the early DI manufacturers. Officially none acknowledge there is an issue, and that wont change IMHO.
01-02-2013, 07:49 PM
#33
Burning Brakes
01-02-2013, 09:00 PM
#34
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St. Jude Donor '13
I would like to see the tech diagrams as to how they are doing it (none we have had in are like that) as that would be a partial solution....depending on how much fuel is introduced upstream of the ports it could help alot, but that negates the benefits of the DI to some extent then as fuel mixture is in the combustion chamber through the entire intake and compression stroke so you couldn't run as high of compression w/out detonation.
Interesting.
01-02-2013, 09:10 PM
#35
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St. Jude Donor '13
Found this! You are correct....we are still seeing almost as bad of intake valve coking so it appears to not be very effective, but the principal behind it is sound:
some applications, gasoline direct injection enables a stratified fuel .... and US markets in 2005 with the 3GR-FSE engine found in the Lexus GS 300. ... The range will include some turbocharged derivatives, including the 1.1 L, .... based on a 5.0L V8 engine block but uses E85 cylinder injection and gasoline port injection.
some applications, gasoline direct injection enables a stratified fuel .... and US markets in 2005 with the 3GR-FSE engine found in the Lexus GS 300. ... The range will include some turbocharged derivatives, including the 1.1 L, .... based on a 5.0L V8 engine block but uses E85 cylinder injection and gasoline port injection.
01-02-2013, 09:16 PM
#36
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St. Jude Donor '13
And more....but they state it is to assist in a better burn under light loads...not for reduced valve coking, but what I really like is the use of a scavenge pump for the newest model...that will help I'm willing to bet:
Vital Stats
Engine : 5.0 L., 8-cylinder
Power: 416 hp
Torque: 371 ft-lbs
--------------------------------------------------------------------------------
8-speed All-synchro
Innovative technologies help to maximize efficiency and reduce emissions, including the SFI D-4 fuel injection (direct-to-cylinder injection system wîth secondary port injectors) and the Electronic Throttle Control System wîth intelligence (ETCS-i). Essentially, SFI D-4 integrates two types of fuel injection: A direct-type high-pressure fuel injection system, which provides a cooling effect in the cylinders and enables the high compression ratio (11.8:1) employed to extract maximum energy from the fuel; a set of low-pressure port fuel injectors that help produce a precise burn to optimize power and efficiency under light- and medium-load conditions.
A dual air-intake system uses a primary intake passage for low and medium engine speeds. In the higher engine speed range (above 3,600 rpm), both the primary and secondary passages are opened, helping boost high-rpm power.
With the IS F 5.0-liter V8, Lexus made a leap in valve-control technology wîth the Variable Valve Timing wîth intelligence by an electric motor (VVT-iE). An electric drive motor alters the intake camshaft phasing, which made it possible to expand VVT operational range to lower engine speeds, where engine oil pressure is usually not high enough to operate conventional VVT. The exhaust camshaft uses hydraulically controlled variable valve timing.
A scavenge pump forces oil from the cylinder heads back to the oil pan, ensuring a reliable oil supply even during cornering that exceeds one g. The low-restriction dual-exhaust system terminates in distinctive stacked quad diffusers.
Looks like alot has been implemented from watching the aftermarket.....Lexus & Yamaha always at the lead in technology.
Vital Stats
Engine : 5.0 L., 8-cylinder
Power: 416 hp
Torque: 371 ft-lbs
--------------------------------------------------------------------------------
8-speed All-synchro
Innovative technologies help to maximize efficiency and reduce emissions, including the SFI D-4 fuel injection (direct-to-cylinder injection system wîth secondary port injectors) and the Electronic Throttle Control System wîth intelligence (ETCS-i). Essentially, SFI D-4 integrates two types of fuel injection: A direct-type high-pressure fuel injection system, which provides a cooling effect in the cylinders and enables the high compression ratio (11.8:1) employed to extract maximum energy from the fuel; a set of low-pressure port fuel injectors that help produce a precise burn to optimize power and efficiency under light- and medium-load conditions.
A dual air-intake system uses a primary intake passage for low and medium engine speeds. In the higher engine speed range (above 3,600 rpm), both the primary and secondary passages are opened, helping boost high-rpm power.
With the IS F 5.0-liter V8, Lexus made a leap in valve-control technology wîth the Variable Valve Timing wîth intelligence by an electric motor (VVT-iE). An electric drive motor alters the intake camshaft phasing, which made it possible to expand VVT operational range to lower engine speeds, where engine oil pressure is usually not high enough to operate conventional VVT. The exhaust camshaft uses hydraulically controlled variable valve timing.
A scavenge pump forces oil from the cylinder heads back to the oil pan, ensuring a reliable oil supply even during cornering that exceeds one g. The low-restriction dual-exhaust system terminates in distinctive stacked quad diffusers.
Looks like alot has been implemented from watching the aftermarket.....Lexus & Yamaha always at the lead in technology.
01-02-2013, 09:56 PM
#37
Le Mans Master
I agree 100% with Greg. Not be a hater but a realist there is little chance that GM oversized fuel system by 2x. I too agree that little will be done until oem supercharger HP car is for sale.
Color me skeptical on the "1000hp capable" OEM fuel system here. Just because the STATIC flow rate of the new DI injectors looks very big at a glance doesn't mean you can deliver that to the cylinders. Remember that a DI system can NOT inject fuel during the power and exhaust strokes. Basically, you end up with about 1/4 of the original injection window that you used to have (time wise) on a port fuel system. Most DI injection actually happens on the intake stroke because we know that it still takes some amount of time for the liquid fuel being injected to actually evaporate and mix with the air charge in the cylinder prior to ignition. This is not a stratified charge DI system (like some European DI engines), so allowing time to evaporate and mix until close to homogenous distribution has been achieved is required for both emissions and power. BTDT.
The biggest hope for the aftermarket would be for GM to have some high output (supercharged?) version up their sleeve where the parts required to make bigger power (injectors, pump) may become shelf items for those looking to "roll their own."
The biggest hope for the aftermarket would be for GM to have some high output (supercharged?) version up their sleeve where the parts required to make bigger power (injectors, pump) may become shelf items for those looking to "roll their own."
01-02-2013, 10:22 PM
#38
I would be extremely surprised an OE supercharger isn't offered on at least one flavor of high output Gen V. We've already seen CAD leeks of the LT4 with what appears to be LS9 style blower.
01-02-2013, 11:06 PM
#39
Burning Brakes
Can you post a diagram of it? Would like to see it. We do valve jobs for the local Lexus dealers under warranty for the coking. They remove the heads and send them out to have the valves manually cleaned. The BMW dealers use a walnut shell media blasting one intake port at a time, and GM ignores it until the customers really complain enough and do manual valve jobs. the deposits on the stem where the guides out way to fast as well.
I would like to see the tech diagrams as to how they are doing it (none we have had in are like that) as that would be a partial solution....depending on how much fuel is introduced upstream of the ports it could help alot, but that negates the benefits of the DI to some extent then as fuel mixture is in the combustion chamber through the entire intake and compression stroke so you couldn't run as high of compression w/out detonation.
Interesting.
I would like to see the tech diagrams as to how they are doing it (none we have had in are like that) as that would be a partial solution....depending on how much fuel is introduced upstream of the ports it could help alot, but that negates the benefits of the DI to some extent then as fuel mixture is in the combustion chamber through the entire intake and compression stroke so you couldn't run as high of compression w/out detonation.
Interesting.
01-02-2013, 11:11 PM
#40
Race Director
If you loom at the flow rates of the pump and injector, that's exactly what they did.