Direct vs indirect injection

[MikeC]

For some reason, this just hit me.

What is the difference between direct and indirect injection. I understand the basics about compression to heat and then injection.

If air/fuel mix is pulled into the cylinder and then compressed, wouldn't there be a problem with timing?

Mike

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1996 SLT Suburban K2500 6.5L TD
tow and off road packages
Automatic Transmission
3.73 differentials
Kennedy 3 1/2 inch exhaust
modified airbox inlet
ISS Pro EGT & boost gauges
TDC at -1.94
second FSD with #9 resistor on an FSD Cooler.
More to come!

[DieselDadd1]

Basicly,the direct injected diesel has no precombustion chamber,unlike your 6.5 turbodiesel which does have one.Indirect injected diesels have the precombustion chamber to allow a smoother,quieter means of operation.There should'nt be a problem with timing if the engine is dynamically timed.Direct injected diesels are noisy but they have proven themselves as being a troublefree design.The Ford 7.3 Powerstroke is an example of a direct injected design.I've seen these dismantled,and I have to say it's a good design,but I don't like the long glow plug tip sticking down in the cylinder.That's the part that concerns me.It does'nt look safe.But,that's just my opinion.I could be wrong.

[turbokid]

A direct injected engine with a mechanical pump is limited to lower rpms. This is because the pump can not inject the fuel quickly and precisely enough (timing) to burn at higher rpms. What happens is the piston actually starts to move faster than the explosion, and that is as high rpm as it goes. A typical DI engine will top out at around 2600 rpm. With the new computerized systems, such as in the powerstroke, they can more effectively inject fuel, allowing for higher rpms. A direct injected engine, because of design principle, (no fuel is wasted in the precup) a direct injected engine is about 20% more efficient than an IDI engine. And, as dieseldadd said, IDI engines are quiter and therefore more desirable to the general public, who are used to gassers.
My $.02


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1984 3/4 Ton Chevy
6.2l threw a rod, so-
6BD1T Isuzu engine
(Direct injected 5.8 liter straight 6)
Aluminum rims, 4" lift, 33" tires


[This message has been edited by turbokid (edited 10-30-2001).]

[This message has been edited by turbokid (edited 10-31-2001).]

[DieselDadd1]

Turbokid,what type of isuzu engine do you have in your 84'chevy?Was it hard to install?You must be pretty talented to repower your truck with that kind of engine.I never heard of a 5.8 litre isuzu before.Very interesting I must say.

[hoot]

Except my direct injected Duramax is a whole lot quieter than my old indirect injected 6.5TD. Especially when it's cold out.

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Mike (dmax) DP Member #2429
2001 2500HD GMC Duramax/Allison Summit White CC/SB Loaded, Amsoil Air Filter, PS2K Propane, 22 Gal. LP Tank on order, Straight Piped, Allison Deep Pan, Transynd Syn ATF, SPA DG-111 Boost/EGT, Nordskog Digital Fuel Level, VentShades, Husky Mudflaps, 255/85-R16 Dunlop Radial Rover RV's PICTURES (http://onramp.uscom.com/~hoot/cars/duramax/gmc)
1994 K1500 Blazer 350 Loaded, Flowmaster duals

[turbokid]

Hoot: I haven't really messed around with Duramaxs', but according to other information posted on this web site, the duramax has various features designed to reduce noise, such as a deep skirted piston block, etc.

Dieseldadd: The type of Isuzu I am in the process of putting in is a 6bd1. It is no longer in production, but you can still get parts. Basically it is just a straight-six diesel, direct injected (also has inline pump instead of rotary) It is rated at 121 hp at 3200 rpm, and about 300 ft-lb torgue, (NA) (We are putting a turbo on when we install.) http://www.62-65-dieselpage.com/ubb/biggrin.gif It is officially called a 353 ci, which works out to 5.78 liters, or 5.8. This engine was actually made in 1980. The engine is being tranplanted out of a 1982 suburban, the suburban was trashed, but the engine is still good. Fired her up and she runs like a dream. http://www.62-65-dieselpage.com/ubb/biggrin.gif The guy who did the original install did most the work. (IE procuring all the brackets, etc.) The engine was installed (in sub) back in the diesel boom days, when just about every diesel manufacturer was making adapters. It has an adapter that goes from the standard #3 bell on the back of the engine to where a turbo 400 bolts right up. (AT 545 would be nice) There is also an adapter that goes from the crank to the flexplate on the transmission. (I am making a new one right now as the old one is broken.) (There is still the standard flywheel which the starter uses, the flexplate is just used to bolt the torque converter to.) The engine uses completely different alternator, ac compressor, ps pump, everything. As for the fit, it is within a couple inches of the firewall, and, with fan, comes within about 3-4 inches of the radiator. Sorry if I have been long winded, i might could post pictures and keep you updated on how the install goes if interested. If you have any more questions or are unclear on something, speak up.

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1984 3/4 Ton Chevy
6.2l threw a rod, so-
6BD1T Isuzu engine
(Direct injected 5.8 liter straight 6)
Aluminum rims, 4" lift, 33" tires

[This message has been edited by turbokid (edited 10-30-2001).]

[This message has been edited by turbokid (edited 10-31-2001).]

[This message has been edited by turbokid (edited 10-31-2001).]

[DieselDadd1]

Very interesting.It seems that engine is one to be trusted.Isuzu has always had a good reputation when it comes to diesels.What happened to the 6.2 diesel?I had one,but it was way underpowered.I also did'nt like the cold engine starting procedure.At temperatures below 32 faranheit,the accelerator had to be depressed fully to the floor while trying to start the engine.I did'nt like to be around it when it started.It's a poor way to start a diesel in cold weather.That's my opinion.Did yours start the same way,according to the decal above the visor?I now operate the 350 oldsmobile diesel at the moment in two chevy pickups.Not the most powerful V8 diesel in the world,but has impressive fuel economy.I've been running the Olds diesel for many years,with absolutely no problem.It's a pleasure to drive.I really like how troublefree it is.Good luck with the Isuzu.

[turbokid]

Well, what happened to the 6.2 was basically this: drove it for a while, overheated, cracked piston, drove it with "ticking" noise for a while, finally pulled a head off to see what the problem was, ended up pulling whole engine, rebuilding, and sticking back in truck along with a banks turbo. It then had all sorts of power, ran great, pulled great, for about a week. Evidently, a bearing cap wasn't torqued down right, came off, took chunk out of block, tore five holes in pan, etc. Decided it was time for a different engine, (which we knew all along) finally go the isuzu, and voila, in a month or so, i'll have a good truck. FOr complete explanation of these events, please see "Banks Turbo Kit" 10-19-01, and "Threw a rod" 10-24-01. Both of these are located in the 6.2 section. About the starting of the 6.2- my sticker said the same thing that yours does, but after glow plugging,and after having plugged in for several hours, it would fire up with no cranking. If it was below 32 and hadn't been plugged in, I would have to do what you said, hold the pedal to the floor. I don't know if it had any adverse affects or not. We used to have a 350 diesel in an old '78 Chevy caprice wagon, it ran for many years, but we finally sold it. Anyways, I might post some pictures when I get isuzu installed- thanks for the good word.

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1984 3/4 Ton Chevy
6.2l threw a rod, so-
6BD1T Isuzu engine
(Direct injected 5.8 liter straight 6)
Aluminum rims, 4" lift, 33" tires

[NH2112]

Turbokid:

I think I'll be able to come up with an AT545 that's currently behind a Volvo TD60 that I want to swap into my K10. Let me find out exactly which SAE bellhousing the Volvo has, and if it's a #3 perhaps we can work out a deal?

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I will choose a path that's clear
I will choose free will

[turbokid]

NH2112- That's sounds good, I might be interested in that transmission, find out what size bell that is, then contact me and I'll see if I have enough money. http://www.62-65-dieselpage.com/ubb/wink.gif That sure would be nice.


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1984 3/4 Ton Chevy
6.2l threw a rod, so-
6BD1T Isuzu engine
(Direct injected 5.8 liter straight 6)
Aluminum rims, 4" lift, 33" tires

[turbokid]

I was browsing on the internet, and I found a spec sheet for the at545. According to it, the only bellhousing that comes on the At545 is a #3. I am interested in that tranny- though I don't know what shipping would be from NH to CO. BTW, my e-mail is t1880jrd@msn.com

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1984 3/4 Ton Chevy
6.2l threw a rod, so-
6BD1T Isuzu engine
(Direct injected 5.8 liter straight 6)
Aluminum rims, 4" lift, 33" tires

[Darrell Lister]

Turbokid: you are correct about the firewall and radatior clearences. My 6BD1 has a manual trans bell housing and currently im running a sm465, but may later change to a nv4500. We had this motor in a 1 ton and it wore it out, It needed new main bearings and i ran across a guy in washington state, and was able to obtain parts for this vintage motor, and reinstalled it into a 1980 3/4 ton 4x4, and basically had to raise the whole truck 4 inches to get the oil pan to clear the 4x4 axle. This motor is one sweet running engine, and it is excellent on fuel economy, and power to boot, as for the turbo it is a tight fit(barely clears the brake booster). If u need any advice for putting it in your truck i can help you there, only thing i need is a A/C compressor mounting bracket ideas. Good luck in the swap

[turbokid]

Darrell Lister- after your post in my guestbook, i wanted to get a hold of you, but you didn't leave an e-mail address. http://www.62-65-dieselpage.com/ubb/smile.gif I just recently posted some more pictures that show the ac bracket on my engine. If you want some better pictures or something, you can e-mail me at t1880jrd@msn.com. In fact, I'll sell you my compressor and mounting brackets if you're interested, we are thinking of putting a different compressor on. BTW, what year was your engine manufactured? The tag on my valve cover says 6/80. What did you do as far as motor mounts? Also, what radiator did you use? Did you have to cut out the crossmember that goes between the framerails? Did you raise the cab or the springs, or both? ALso, what rear end ratio do you have, and fast can you comfortably go? What kind of turbo do you have and how much boost do you get out of it? Sorry for so many questions.
Thanks,

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1984 3/4 Ton Chevy
Tired of 6.2's after 16 years of ownership, and after one threw a rod 200 mi. after rebuild, so-
6BD1H Isuzu engine
(Direct injected 5.8 liter straight 6)
Aluminum rims, 4" lift, 33" tires
http://www.picturetrail.com/turbokid

[This message has been edited by turbokid (edited 11-10-2001).]

[Tough Guy]

The Duramax is quiet because of "pilot" injection, this is possible because of the high pressure fuel rail system.

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300HP 6.5L Intercooled Turbo Diesel
0-60 under 9.0 sec.
Member #136
18 MPG

[turbokid]

Also pilot injection is possible because of computer controlled injection timing. An N14 cummins also has a high pressure fuel rail, and in the old style PT system, or pressure timed system, but injection times are controlled by extra lobes on the cam, pushrods, and rockerarms, and it is still loud. (Even with high pressure common rail fuel system.)

------------------
1984 3/4 Ton Chevy
Tired of 6.2's after 16 years of ownership, and after one threw a rod 200 mi. after rebuild, so-
6BD1H Isuzu engine
(Direct injected 5.8 liter straight 6)
Aluminum rims, 4" lift, 33" tires
http://www.picturetrail.com/turbokid

[hoot]

The Powerstroke also has pilot injection.
Split-shot injectors were originally installed on 1996 and 97 model/year trucks with California emissions, and are used in engines from 98.5 on.


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Mike (dmax) DP Member #2429
2001 2500HD GMC Duramax/Allison Summit White CC/SB Loaded, Amsoil Air Filter, PS2K Propane, 22 Gal. LP Tank, Straight Piped, Allison Deep Pan, Transynd Syn ATF, SPA DG-111 Boost/EGT, Nordskog Digital Fuel Level, VentShades, Husky Mudflaps, 255/85-R16 Dunlop Radial Rover RV's PICTURES (http://onramp.uscom.com/~hoot/cars/duramax/gmc)
1994 K1500 Blazer 350 Loaded, Flowmaster duals

[Tough Guy]

Pilot Injection
The sophistication and technology of the direct injection system components make the Duramax engine capable of employing a process known as "pilot injection."


Pilot injection involves injecting a small amount of fuel into the cylinder prior to the main injection event. A complex process in the electronic controls selects the optimal time, duration and quantity of pilot injection, coupled with the main injection charges.


The result

[hoot]

turbokid,

You're right. Here's the scoop on the rest of the low NVH features....

"Decibel readings provided by GM show that the new Duramax diesel generates just
half the noise of its next quietest competitor, the Ford Powerstroke. This low noise, vibration, and harshness (NVH) stem from the structural rigidity of its deep-skirt block design, its side-bolted main bearing caps, single-piece aluminum crankcase and full bell housing. The low noise is also due to the widespread use of isolating
gaskets, laminated heat shields, laminated oil pan, and cast aluminum valve covers.

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Mike (dmax) DP Member #2429
2001 2500HD GMC Duramax/Allison Summit White CC/SB Loaded
Amsoil Air Filter
PS2K Propane, 22 Gal. LP Tank PIC (http://onramp.uscom.com/~hoot/cars/duramax/gmc/propane/bigtank1.jpg)
Straight Piped PIC (http://uscom.com/~hoot/cars/duramax/gmc/exhaust/jvn03.jpg)
Allison Deep Pan, Transynd Syn ATF PIC (http://uscom.com/~hoot/cars/duramax/gmc/allison/allis10.jpg)
SPA DG-111 Boost/EGT, Nordskog Digital Fuel Level PIC (http://uscom.com/~hoot/cars/duramax/gmc/allison/allis11.jpg)
VentShades, Husky Mudflaps, 255/85-R16 Dunlop Radial Rover RV's
Headlight Booster Kit from Kennedy Diesel (http://www.kennedydiesel.com)
TRUCK PICTURES CLICK HERE (http://onramp.uscom.com/~hoot/cars/duramax/gmc)
1994 K1500 Blazer 350 Loaded, Flowmaster duals