Is SEQUENTIAL INJECTION REALLY NEEDED?

tonydanzah · Post by **tonydanzah** » Sat Jan 27, 2007 8:36 pm

It was proven on the dyno at my school that SFI is better than Bank fire injection, but only for like 8-10hp by one of my teachers. But when you start talking about direct injection there is no other way then SFI and the hp gains are rediculous.

Bill Hincher · Post by **Bill Hincher** » Sat Jan 27, 2007 8:39 pm

explain?

tonydanzah · Post by **tonydanzah** » Sun Jan 28, 2007 5:06 pm

uhh no, direct injection is so awesome because it is so efficient at atomizing the fuel. Instead of the 20 yr old style of spraying the fuel into the the intake ports where is waits gets to get hot and atomize better or gets colder and then can puddle before the intake valve opens and lets it in. on DI the fuel is sprayed in on the compression stroke usually bounced of the top of the piston. just like in a modern diesel engine. since it is bounced the fuel has a beter atomization rate. Also since the injection is so much more precise and controllable beside the fact of how much more fuel pressure DI systems run to overcome the force of compression, the injectors can be continued to be sprayed as the piston travels back down contiuing the burn and combustion efficeny all while lengthing the torque stroke. Which is exactly the way the do it in modern diesel DI. I will see if I can find a article online, since my text books have the information but i do not have a scanner.

tonydanzah · Post by **tonydanzah** » Sun Jan 28, 2007 5:09 pm

to clarify from my first post all DI is sequential, not sure if i made it seem otherwise by my wording. DI is a super precise SFI but with fuel pressure around 100-200psi. so those of you familiar with doing a prime and bleed on a diesel engine after changing a fuel filter will understand the same with most likely need to be done with a gas DI system.

Bill Hincher · Post by **Bill Hincher** » Sun Jan 28, 2007 5:33 pm

Its a sequential 'stratified' system first used on the 1955 300 Mercedes 300 Sl gullwings
The early Honda's used a variation of that same system in thier CVCC engines, controled vortex combustion chamber, it was really neet, you had two right hand pistons and two left hand pistons

tonydanzah · Post by **tonydanzah** » Sun Jan 28, 2007 6:00 pm

yes i know fuel injection has been around for a long time, but i am talking about "modern" fuel injection.

Robert Venable · Post by **Robert Venable** » Sun Jan 28, 2007 9:38 pm

Tony,

I've gotta tune in on this and refute some of your info.

Direct Injection is normally expressed in thousands of Psi, not hundreds.(UP TO 120 BAR{1764 PSI} in BMW's N73B60 and the new N54 has up to 200 bar {2940 psi} with it's new Piezo injectors, I've heard of injection pressures reaching 50k psi on Mack's new diesel engines).

Direct injection normally injects fuel during the compression stroke, which can easily reach 1500 psi. So, to continue to inject fuel into the combustion chamber during combustion you need to have a higher pressure (fuel travels from high to low just like all other fluids) . Then to have it atomize better you have the even higher fuel pres. This is the entire reason the fuel atomizes so finely, not because it is hitting the piston. Infact, on a diesel engine, if the raw fuel hits the piston it will actually melt tinny pockets (possibly even holes, eventually) into the surface of the piston-(take a look at what a DI Diesel engine's piston looks like after an injector gets stuck open during running- looks like the surface of the moon). Not sure if it is ok to have faw fuel hit a DI gasoline engine's piston.

The advantages of DI that I have found are:

Cooler combustion chamber to allow for increased air density and compression ratio (How does 10.2:1 sound with 10 psi of boost?? This is what the N54 In my 335 runs)

Less fuel required to reach the correct A?F ratio- this is because of (as TONY said) the fact that it does not puddle or condense.

BILL,

My information shows that the first passanger car to use DI was a 1952 Mercedes called the "Gutbrod."

tonydanzah · Post by **tonydanzah** » Sun Jan 28, 2007 10:22 pm

I am aware of what the DI systerm psi is on a diesel engine, but i don't think the specs are anywhere near as high of a gas motor. A gasoline engine has no where near the compression ratio of a diesel even on a gasoline engine at high boost as it is not a compression ignition system. I was just looking around the net for some specs of the DI system on the new pontiac solstice turbo but i could find none. Either way DI will be on all cars in a few years as well a trend with the new camless motors, where the valves are actuated by solenoids.

Robert Venable · Post by **Robert Venable** » Sun Jan 28, 2007 10:30 pm

Umm, I didn't mean to make anyone think that Diesel injection pressures are anywheres near gasoline DI injection pressures. Nor did I try to make anyone think that DI gasoline engines are combustion ignited. Thats why I gave specs for both gasoline and Diesel injection pressures that are very different. But, since we are on the subject, today's gasoline DI injection pressures are actually exceeding injection pressures in Diesels engines built as soon as 20-30 years ago.

About Camless engines, I've heard that International diesel actually has had a running camless engine for about 5+ years now). Last I heard was that they were trying to find away to slow the solenoids down to prevent from breaking the heads of the valves off.

BTW: Since you can't find any specs on the Solstice, do you know where you can find any on the VW/Audi FSI engines??

tonydanzah · Post by **tonydanzah** » Sun Jan 28, 2007 10:45 pm

Not sure on the specs for the Audi but i can look for them. As far as the camless engines the BMW 7 series i believe has been running the camless design for a couple years. I think they might also run them in a few others, but not in any of the m-series. It has something to do with the piston speed getting to fast at high rpm for the solenoids to work.

tonydanzah · Post by **tonydanzah** » Sun Jan 28, 2007 10:57 pm

http://www.autospies.com/news/Volkswage ... ine-10829/

the article for ccs engine is really good and the technology sounds interesting, but no matter what they do i will always think VW and audis are overpriced pieces of junk. I will go japanese over european any day, with the exception of volvo.

Robert Venable · Post by **Robert Venable** » Sun Jan 28, 2007 11:13 pm

HMM, pretty sure they have cams. I've worked on a few.

BTW: I'm a UTI Auto/Diesel/and Industrial graduate, and a BMW STEP Graduate. Been working for BMW for a couple of years now and can tell you they still have Cams. You might be confusing there Valvetronic with being camless.

Valvetronic is actually a system that still uses cams, but it adds a 3rd shaft (in addition to the intake and exhaust cam shafts) that is an eccentric that is operated by an electric motor to varry the valve lift of the intake valves. This allows for you pretty much elinate the throttlebody, but BMW still uses a throttle body for Limp home mode and to maintain a slight vacuum to suck in evaporative emmissions.

You are correct in that the M series does not use Valvetronic. All M series engines currently produced use individual throttle bodies per cylinder. I believe this was for weight reasons, but BMW doesn't really say anything in the books I have.

Now, there a race engine (the P84/5) that the new E60 M5's S85 engine is somewhat based off of. It is Camless. But instead of solenoids it uses pneumatic valves. But at 19k rpms you pretty much need this to replace valve springs.

Robert Venable · Post by **Robert Venable** » Sun Jan 28, 2007 11:14 pm

tonydanzah wrote:http://www.autospies.com/news/Volkswage ... ine-10829/

the article for ccs engine is really good and the technology sounds interesting, but no matter what they do i will always think VW and audis are overpriced pieces of junk. I will go japanese over european any day, with the exception of volvo.

And your reasoning behind this??

tonydanzah · Post by **tonydanzah** » Sun Jan 28, 2007 11:43 pm

the 1980s VW rabbit, with gasoline engine. The shear price of any componet on BMWs and MBs. I hate most of the styling on these cars, they weigh 9000 lbs and are not fast unless you are willing to 90k compared to most japanese cars.

Robert Venable · Post by **Robert Venable** » Mon Jan 29, 2007 12:27 am

Hmm, not sure what you are reffering to when you talk about the Rabbit. But I can tell you most manufactures have had a turd at one time or the other.

Prices are different for every part on every vehicle at almost every dealership (some charge no shipping and higher than MSRP, some charge you for shipping, etc.).

9000 lbs you say?? The heaviest BMW I can find sold in America is the less than 5400 lb AWD X5 SAV.

Fast you say?? When was the last time a Japenese manufacture made a car that would smoke a C5........ and had 4 doors?

When was the last time an american manufacture bragged about using Japanese engineering, as they do German engineering?/

tonydanzah · Post by **tonydanzah** » Mon Jan 29, 2007 12:53 am

sounds like i touched on a nerve. 9000 lbs was an exaggeration, but either way your on the wrong forum if you love bmws and all of the junk german, eruopean cars, except of course volvo. If some one gave me a bmw 745, i would pour a little sand in the oil, take it to a mitsu dealer that still had evos on the lot and a trade it in, or to a ford dealer and snag a new svt cobra.

Robert Venable · Post by **Robert Venable** » Mon Jan 29, 2007 12:59 am

LOL, but I'm on the right forum if I love VOLVO?? LMFAO

As far as love, I love my 1990 Mighty Max which I'm in the process of building a 4G64 w/4G63 head. I simply work for BMW, but It's always fun to watch someone explain how much they hate something and not be able to come up with a decent reason for doing so. Then after they make something up and you prove them wrong you get a statement saying how wrong you are for some reason or the other. Sorry, I just find it amusing.

tonydanzah · Post by **tonydanzah** » Mon Jan 29, 2007 1:06 am

haha i knew you have to be a bmw tech. Any of the kids i go to school think they are hot shit if the work on bimmers or MBs. But guess what to me a car is a car if you are a tech. All have their pros and cons. If they were are great as you think they are then why is Toyota posed to take over the number one automaker spot? haha bmw tech, enjoy that. haha guess what if you go to UTI they won't even look at your application into the bmw msat program seriously unless you have taken the ford classes. Since the have some of the most complex electronics system on cars, i didn't believe it either at first. But wait robert there's more! Let me guess your in your young 20s, and a level 1 tech. So all of your money goes towards tools, so if you did drive a bmw you could only afford a 525 or 535, but hey any bmw is better then no bmw right? Right!

Robert Venable · Post by **Robert Venable** » Mon Jan 29, 2007 1:24 am

tonydanzah wrote:haha i knew you have to be a bmw tech. Any of the kids i go to school think they are hot shit if the work on bimmers or MBs. But guess what to me a car is a car if you are a tech. All have their pros and cons. If they were are great as you think they are then why is Toyota posed to take over the number one automaker spot? haha bmw tech, enjoy that. haha guess what if you go to UTI they won't even look at your application into the bmw msat program seriously unless you have taken the ford classes. Since the have some of the most complex electronics system on cars, i didn't believe it either at first.

I'm sorry if I misunderstood any of your post, but I'm doing my best.

I will aggree with you on the pros and cons part, but you can't tell me a DODGE VIPER is just as much of a car as a Kia Optima. You are claiming that "a car is a car," yet because BMWs have "some of the most complex electronics system on cars" there is no way to make it into STEP w/o FACT training?? So, since I didn't take Ford FACT, you are claiming that I did not make it into STEP? (WTF IS msat??) IF this is true, then explain to me how I graduated from BMW STEP??

Toyota is "posed to take over the number one automaker spot" because they sell alot of Camary's and other boring cars that appeal to a wide range of people around the world. BMW has there ups and downs, but when it comes to it, BMW sets the standard for things around the world. No other automaker has been able to get the brand recognition that BMW has had with there 3/5/7 series. No other major automaker is still independently owned as BMW is. I could go on, but whats the point.

tonydanzah · Post by **tonydanzah** » Mon Jan 29, 2007 1:33 am

So then Toyota is not indepently owned? The fact that they buy and sell other manufactures does not make them indepent? I'm not really surprised you made it into the step program, being from a state where being a highschool dropout is not a uncommon occurance. So since you seem relativly intelligent I am not surprised at all. An MSAT is manufacture specific advanced training. Which means if you get into the program, the step program is 18 months and is free, you just sign an agreement to work at a BMW dealership for a minimum for 2 years. If you go to uti, at least in IL there are tons of other very intelligent people. So they don't just want to you get into step, they want to raise bar so only the best get into step. The failure rate for the Ford FACT is high in the electronics area and supposedly if you can pass it the bmw electronics becomes a breeze. Anyways I have been really enjoying these heated arguements on these forums. I hope to see you keep posting as i am loving every minute of this. Hopefully when I get back from the gym in an hour or so there will be another response.

Robert Venable · Post by **Robert Venable** » Mon Jan 29, 2007 2:13 am

Do a Search on a book titled "DRIVEN." I can't recall the author, but it is a very detailed book on BMW as of about 2003ish or so. It can tell some things you would find VERY interesting. And when I say Independent, I'm referring to the fact that Toyota is "Toyota Motor Company, " Meaning that it is made up of multiple brands As is General Motors and Ford Motor Company. BMW, is Barvarian Motor Werks. They own MINI, the ROVER name, and I believe Rolls Royce.

It's pretty ignorate of you to use my state as some kinda way to put me down and discredit me. Expeacially considering that it has nothing to do with UTI (I went to UTI of Houston, there is no Louisiana location). The BMW STEP program is 27 WEEKS long, not months. There is no "MSAT" longer, and certainly not one 18 MONTHS long. STEP is NOT free. Dealerships currently pay BMW $10k for the training you recieve (it was $7500 and a 6 month contract while I was in STEP). They pay this if you stay the 2 years, otherwise you do.

Now that you mention it, I guess I was a shoe in considering all the morons, and the lack of intelligent people as in Chicago, that apply into STEP. I was 1 of 2 that got into my STEP class- this was after over 85 people interviewed. I was 1 of 15 people who got into the class. A class made up of someone as far north as Alaska, as south as Mexico, as far east as Buffalo, New York, and as far west as Seattle. Then again, there were guys who came from the Phenix Campus, one from one of the California Campuses, one From the Nascar Campus, and even a couple from Chicago (the New Yorker and one from D.C. for EX.) And now that you mention it, they must have all been complete morons considering I placed top of my class.

Some did have FORD FACT training, some didn't. All had 4.0 GPA's (btw whats your's?), 99.5+ Attendace ratings, Atleast 1 SOP, and as high as 18 SOPs(I believe you guys call them SOC's now).

In STEP, the training from FACT doesn't help much. Mostly because BMW's use BUS systems, and Fiber Optic systems. Which as far as I know FORD has not put in place yet (or atleast they had not 2 years ago). The biggest thing with STEP is the remeberization. We actually had to draw out the wiring harness/bus system, off of memory, in the parking lot with chalk on the E65 745i. This car has over 88 Control Modules last time I counted And that was before they added things like night vision, Active Cruise Control with "Stop and go", etc. So, if you are considering one of these programs and think FACT will make it a breeze, you better think twice.

Bill Hincher · Post by **Bill Hincher** » Mon Apr 07, 2008 10:03 pm

It takes 9000 gallons of air to burn one gallon of fuel, nobody ever answered that question, but those are the numbers
well? whats that got to do with electronic fuel injection?
because I can convert that number to weight
9000 gallons of air weighs 90 lbs one gallon of gas wieghs 6 lbs
welllllllllllllllllllllllllllllll, thats nice, and if I had a dollar , that might buy me a cup of coffee sooooooooooooooo?
I been thinking about it, Horsepower is directly related to how many lbs per hour of fuel the engine can burn, everybody wants a bigger , badder fuel pump with huge injectors and they all know how many pounds of fuel they can deliver but you have to supply the engine with enough air to burn the fuel. so if I can dictate the lbs per hour of fuel, I can match the lbs per hour of air required
the importance of knowing that value would supply me with the right intake manifold, especially the plenum size, because the plenums volume wants to be 50-75% of the displacement of the engine.The plenum is a resivour that maintains an amount of air that can be delivered on short notice before the turbo spools up, but it must not be too large or it will cause lag, because it takes more time for the turbo to fill the resivour

Robert Venable · Post by **Robert Venable** » Mon Apr 07, 2008 11:27 pm

ok???

Bill Hincher · Post by **Bill Hincher** » Tue Apr 08, 2008 9:41 am

well, if I can find how many lbs of fuel I can efficeintly burn per hour in a 2 liter engine, I can find how many lbs of air is required, I can convert that number to CFM for a decent throttle body, then resize the runners for volume of air and size the plenum accordingly