out2kayak

Like it or not, much of the physics within the internal combustion engine has been well known for sometime now. The biggest thing that can change is the software control of the environment, which is where I come in.

The thing that I don't get is there is a certain energy density for each substance. E-85 has less (~25.65 MJ/L) and Gasoline has more (~34.2 MJ/L). Thus, in a given system it takes more E-85 to produce the same amount of energy as gasoline. To keep up with this delta, some of the other chemical properties have to be used to make up the delta (that's why E-85 can tolerate higher compression). Consider:

Properties Ethyl Alcohol Gasoline
Boiling Pt 78.3°C 38.9°C
Flash Pt 12.8°C -42.8°C
Lower Explosive Limit 3.30% 1.40%
Upper Explosive Limit 19% 7.60%

For a given system, changing fuels will have a significant impact on the overall system. For E-85, you have to worry about how it reacts with fuel system components, how it absorbs water, etc.

One such change is that the fuel system will need to flow a significant higher quantity of E-85 to produce the same amount of HP. If you don't believe me, look at Weldon or any other fuel pump manufacturer's website.

As I read it, BG asserts that E-85 is some magical elixir that will make this engine awesome and the fuel system can keep up. The challenge I see is that GM already produces flex-fuel vehicles, all at a lower HP rating (no where near LS9 levels). To produce such a car, all of the fuel system would need to be significantly upgraded to flow sufficient fuel. It's basic physics.

Whenever one creates a vehicle, everything is a trade. Size, weight, power and cost (SWAP-C) is typically the quality factors that must be contented with in order to produce a product customers will buy at a specific price point. Add in more size, you have more aerodynamic drag and more weight, thus you will consume more fuel to move the vehicle. Add support for E-85 and you add sensors (to detect the type of fuel), larger fuel lines, bigger pumps, etc.

The other challenge is government regulations. Navistar has closed up shop because they cannot produce a diesel engine that meets federal emissions standards. GM has federal emissions standards they must meet as well. Also consider the CAFE requirements, where in 2025 we are looking at 61MPG for passenger cars. Given this is a brand new, clean sheet design that is to come in 2014 time frame, this engine will be significantly impacted by these regulations.

So, either GM has come up with something very new in the market place (i.e. it runs on puppy dog kisses), they have increased the cost of the vehicle or they have removed content.

For removal of content, see what happened to Chrysler in the later 1990s when they did that to most of their vehicles. It was bad enough where one of the guys I know ended up running a FEA model on the aluminum part that connects the tumbler to the ignition switch so they can make the metal as thin as possible yet last to just beyond the warranty period.

For new content, VVT, DI and other such tech has been on the market for quite some time. It is nice that GM is finally catching up, but it is a known commodity.

Thus my assertion that BG is more of a management person. If he is an engineer, he would have brought more meat to the table verses something that, frankly, could be found with Google and stated with a bit of bravado.

The other point I would like to make is that, when someone is setting up an architecture for a system, they define specific key quality attributes. These attributes drive how the different trades will be weighted and have a significant impact of how the system comes together. The area where the aftermarket comes in is when the end user / customer wants to impact these quality attributes. For example, they sacrifice fuel economy for better performance, because the use case of the vehicle is more for racing. Or they install a better audio system because they want a better driving experience. Bottom line is that the priorities the owner has are different than what the engineering community came up with and the aftermarket fills this gap.

In the aftermarket, there are some people who are highly skilled at what they do. Consider Tom Nelson of NRE, Smokey Yunick and so on -- all highly talented and knowledgeable. There are many folks who will pick apart the vehicle and will find ways to force the quality attributes one way or the other.

midnightbluS10

TO expand on this, here's what carried over

1bad lad

Mr. gunnz. Do you work in the wixom michigan facility?

Bigg_Gunz

Answering this question would surely blow my alias. Please understand I am not at liberty to reveal that type of information. The information I have given you is a 100% accurate from the beginning of this thread and even now.


Bigg Gunz

Bigg_Gunz

Well I'm most certainly flattered, I have to say I am not a GM Rep. What I am is a "Advanced Combustion Engineer" from somewhere within GM. I am here for one reason only as directed, and that was to reassure what is happening with the 2014 LT1. I do NOT engaged critics or those beyond reasonable thought. Yes, I have strict limits on what I can & cannot say. If I encounter a grey area on releasing information. I must report back for a GO or no GO. I can say with confidence one thing, everything that I have stated in this thread is 100% accurate. This particular thread is monitored extensive by someone high within GM, as I've walked a very fine line. Anything negative or lashing out due to speculation is removed from my report as this is unhealthy in our focus groups and brain storming secession. However anything that is of substance or real concerns by true gear heads on here, is address in our meetings. Then its voted on by engineers and if it requires action, then we are green lighted for developing what is needed if it is needed. It is not real time however it less than 3 weeks for a model or simulation. I and others are placed on this site for various reasons and the information from true gear heads with integrity and courtesy is invaluable to developing a well received product. I just decided to log in.


Bigg Gunz

disc0monkey

iTrader: (10)

bigg gunz, can you comment on the LS2 intake manifold? was it made to make less power than the LS6 to meet a power requirement? just something that always made me wonder..

Robert91RS

iTrader: (2)

Thank you for addressing my questions BG. While not completely thrilled with all the news you have brought us, I am grateful for you taking the time.

I thought of one more for you. What about correcting the speedo for gear swaps, will that be possible with these new E92 equipped cars?

mikestypes

Unfortunately, there is one thing you are missing. On a DI engine, the injector cannot fire for 720deg of crank rotation like a PI engine. The fuel cannot be injected for a large majority of the exhaust stroke and during the power stroke. This means that at best, you could have half your calculated power. Still alot!

I appreciate your information in this thread, but this is a stretch. Direct injection engines have beein using tri-lobed cam drives for almost a decade. My 2007 car (Mazda) has a high-pressure fuel pump driven by a tri-lobe on the end of the intake cam. Also, the LNF (2.0 Turbo Ecotec) has used it for many years too....

DrkPhx

iTrader: (15)

Is that true for all future GM V8 engines including the upcoming LT4 and Big Brother? I have to believe VVT is less intrusive in performance applications and less so for the big hp motors.

dbs1

Ok Mr. BG...I stayed up late after watching for news updates all day long per your heads up last week concerning more revelation on the new beast today, and...nada.

I was sure there was going to be something about me receiving a gift of an LT1 with a nice new shiny C7 wrapped around it. What happened?

Bigg_Gunz

Question... Did you skip the entire section that clearly stated that a aerospace engineer give one of our guys/engineers a ride because his car was stolen at the Superbowl? That the car the aerospace engineer had an rotary engine? That they had a conversation? Attention to detail is everything. Not once did I state GM developed the tri lobe. I said they had a conversation during the ride. And obviously he knew of a solution or how to fix part of the puzzle. Although it is uncertain between what really happen. But just maybe that engineer knew his pump had a tri lobe or the mechanical physics of the rotary engine would surely work in our stalled project. No stretching was done. PAY ATTENTION TO EXACTLY IS BEING STATED.

Good morning to you sir

Bigg Gunz

Bigg_Gunz

Hang tight, I am sure more information is going to be release soon. I'm NOT sure what happen with Monday release, or why the change for it. It is coming I can assure you of that so hang in there.


Bigg Gunz

Bigg_Gunz

VVT is here to stay I am concrete with that statement. As we are still in testing with big brother I am not allow to elaborate additionally on that.


Bigg Gunz

Bigg_Gunz

Yes you can make those needed adjustments, The only thing that is off limits in the E92 ECM is Fuel tables and High Pressure Solenoid Fuel tables. There isn't really any bad news given, this is going to be a fun engine for the aftermarket and regular consumer. Everyone will win in the end.


Bigg Gunz

Bigg_Gunz

The LS2 manifold has more volume/space than a regular LS6 manifold. This is due to the larger displacement of the 6.0 engine vs 5.7.

So taking a LS2 manifold and putting on a 5.7 you will lose some power and some torque. Due mainly to the velocity drop and pressure waves produced. The port shape is slight different as well this will also rob some power.

My question is what do you have the LS2 intake manifold installed on? As I can give you a exact accurate reason.

Bigg Gunz

disc0monkey

iTrader: (10)

I think you covered it with the LS2 making less power on the LS1/6. IIRC some have even gone far enough to report the LS6 making more(minute) or same horsepower on the LS2.

I believe it is common knowledge at this point the LS2 intake is a big hinderance on that motor. a swap to a FAST does more for an LS2 then any other LS varient.

Bigg_Gunz

This has a lot to with port design/shape. The port design/shape drives the velocity.


Bigg Gunz

disc0monkey

iTrader: (10)

Last random question, will a stock 4th gen exhaust with a gutted cat loose power over replacing the cat section with a straight pipe?

ringram

What you are suggesting is that GM has built in a boosted tune capability with the stock NA ecu. Otherwise how would 3bar pressure be accounted for in the fueling tables. What about spark timing under large airmass. The same GM built in capacity must exist from what you say. (This is possible given whats in some of the current ECU's)

You are also suggesting that fueling is locked. So for an NA app vs an FI app the fueling will not be optimised for both. This is a fail then. And people will still want to mess with fueling, perhaps by running a programable MAF etc.
The only way it would work properly if the ECU has a feedback loop and perhaps even wideband closed loop.
But if previous models are anything to go by OEM fueling is not optimal LBT. Nor is timing set at MBT across the load range.

So at best it will be a kludge and at worst pointless IMO.

But happy to be proven wrong. I guess we will see when the first cars hit the dyno.

As long as we can mess with the airflow tables or sensors we will have fueling control

disc0monkey

iTrader: (10)

resistor MAFs back in action LOL