49mpg possible from full size mechanical diesel?

[bondvagabond]

In Europe where they hotrod diesel cars more than the US, the 1.9tdi's and 1.6 turbos are getting snapped up, so they are starting to mess around with the 1.6 na's.

I know jack all about turbos, get someone more knowledgable than me to double check your turbo choice.

Things I do know that give you extra margin for error:
Get a pyrometer
Arp head studs are available
One brand of 1.9tdi head gasket is usable as an upgrade.

Also, I guess you don't want to surface the head at all if warped an these vw diesels, because the cam gets pulled out of alignment due to integral cam bearings. You could maybe find a "real" machinist who could cut head for removable cam bearings then line bore cam journals, but would probably exceed cost of new head.

[bondvagabond]

Hey oil pan, would this be a good match for my 7.3, not hauling much weight and cruising 60mph at 1600rpm?

Big-azz turbo

[Isaac Zackary]

I know a company that heats and bends warped VW water-cooled heads back into shape. But my head is fine.

Still, any plus or minus on using a supercharger over a turbocharger?

[bondvagabond]

Originally Posted by Isaac Zackary

I know a company that heats and bends warped VW water-cooled heads back into shape. But my head is fine.

Still, any plus or minus on using a supercharger over a turbocharger?

Used to be turbos had a lot of lag, before the power kicked in. I've heard people say that turbos are more efficient than superchargers.

I've always wanted a supercharger on a clutch like mad max 2 so I could push "the button". An engine builder I knew explained to me that on a roots type blower this doesn't actually work because if they aren't worn out not much air gets through them when they aren't spinning. But you could rig up a one way valve to let air in when the blower was off.

[oil pan 4]

Most blowers used in gasoline applications have a bypass valve built into them
Certain years of supercharged Toyota MR2 use a clutched supercharger. Toyota claimed that not spinning the blower when its not needed saved them 2mpg.

On a diesel you want air being forced into the engine all the time. That waste heat that goes out the exhaust is doing work via the turbocharger and force feeding more air into the engine. Diesel engines are not like gas engines, diesels need all the air they can possibly get all the time. This helps their fuel mile age and power. Completely opposite of how a gasoline engine is.

Now if I had unlimited time and money or a 6-71 blower miracle its self into my possession I would love to experiment with some turbocharger over supercharger violence.

Originally Posted by bondvagabond

Hey oil pan, would this be a good match for my 7.3, not hauling much weight and cruising 60mph at 1600rpm?

Big-azz turbo

That may be a T76. I think its big enough for a 7.3L.
You are trying to do just about the same thing I am by shooting for 1600rpm at 60mph.
If there was an easy way for me to just run my T76 by its self I would, just to see what its like.

Then if you cant use it, don't want it or don't like it, sell it to me. That T76 looking turbo with large exhaust housing would make a great lazy atmospheric turbo for my set up. The P-trim T76 ends up doing most of the work of the 2 turbochargers and it should be the other way around.

The pictures are of my T76 exhaust housing when I coated it and the other one is of the large HE351VE turbocharger getting setup to be force fed by the even larger T76.
The 2 turbochargers together are so heavy a attached them to my engine stand. Used properly these turbochargers could support around 3000 horsepower. They have an easy life, I don't push them any where near their full capability.

[Isaac Zackary]

Originally Posted by oil pan 4

Most blowers used in gasoline applications have a bypass valve built into them
Certain years of supercharged Toyota MR2 use a clutched supercharger. Toyota claimed that not spinning the blower when its not needed saved them 2mpg.

So a turbocharger kind of selfregulates. Correct? I mean when you let off the accelerator there's less turning it, whereas a supercharger is completely RPM dependent. Would there be any advantage in bypassing the turbine with a turbo? Probably not, especially with a diesel.

Originally Posted by oil pan 4

On a diesel you want air being forced into the engine all the time. That waste heat that goes out the exhaust is doing work via the turbocharger and force feeding more air into the engine.

I've thought about that too. Usually when the exhaust valve opens there's still pressure in the cylinder that just escapes in a loud POP! So unless you have an atkins cycle engine that has a longer combustion stroke than it's compression stroke the only way to utilize that extra pressure would be to run another engine, such as a turbine. I've wondered if instead of runing a superchargering wheel off the turbine if it's possible to maybe run something else, like an alternator. But if more air=more efficiency then I guess I better figure out how to addapt a turbosupercharger (there! I said it!) to the engine.

Originally Posted by oil pan 4

Diesel engines are not like gas engines, diesels need all the air they can possibly get all the time. This helps their fuel mile age and power. Completely opposite of how a gasoline engine is.

Yes, in practice this is usually true of gasoline engines. However, I've found it very interesting to find that a gasoline's most efficient tune is full throttle, low RPMs and leaner than stoich. I'm not saying that's good for longevity but it's best for efficiency. But now I'm really derailing the thread. Sorry.

So, I think the piston oil squirters and forged pistons such won't be as necessary if I don't go to crazy with the fuel screw when I get a turbo on there. Just another question, right now the stock exhaust is really tiny. Looks like about an inch and a half diameter. I'm guessing with the turbine causing a restriction, plus more flow, I should think about enlarging the exhaust diameter. Right?

[oil pan 4]

The only time you want to bypass turbine drive pressure is with the waste gate. Use the waste gate to limit boost pressure.
The supercharger is rpm dependent. In an old 2-stroke Detroit diesel the blower is setup to feed the engine an average 2 pounds of boost, through the entire operating range.
If you want more boost, you have to add a turbocharger.

I have ran a few diesels with no exhaust manifold or only an exhaust manifold. They are not as loud as you would expect.
Right now I run the my 6.5L with a straight pipe coming off the turbo.

Gasoline engines are most efficient at full throttle because you eliminate isobaric losses. Isobaric losses on a small 4 cylinder gas engine can be around 2 horsepower at cruising speed. V8 engines have even higher isobaric losses.
This is the entire reasoning behind the cylinder deactivation the OEMs are using now.

Think hybrid engines are something new? Nope. The turbocharger is another engine. Turbodiesels are the original hybrids.

On the 1.6, just run a 2 or 2.5 inch after it comes off the back of the turbo. You want as little restriction as possible after that turbo. I believe the factory down pipes on the K03 and K04 turbochargers are 2.5 inch. The KO3 and 4 series uses its own down pipe setup, the waste gate and turbine discharge dump into a shared plenum and the plenum is like 4 inches in diameter and then reduces down to the smaller pipe. Any down pipe off any car equipped with that turbo will work, you will just that plenum and reducer. Chances are you will have to cut the down pipe a few inches after it reduces down.

[ocnorb]

I wanted to say hello and get subscribed to your thread. I've owned several IDI Fords over the years, including one I'm currently working on that is in a '57 IH pickup truck.

My '86 was a crew cab dually and I set it up primarily to haul a heavy trailer. It excelled at that with an ATS turbo kit. With a larger turbo, methanol injection and a ZF5 I was able to easily get 18mpg unloaded. At the time I had no concept of eco-modding so no coasting or other strategies were in play.

My '57 has a 6.9l motor with the ATS van factory kit. Ford dealers installed these in many new vans before made them an option in '94. This one will get ARP head studs and I hope to swap in a ZF-5 to replace the C-6. Being a fairly light and somewhat aero old truck, I'm shooting for 25-26 mpg. Perhaps more if I glean some more gems from this thread!!

[ToddT58]

Ocnorb, what rear end ratio did you have? And what are you running now? It seems like rpm is the big issue. I had a '93 7.3 IDI crew cab dually with a 4.10 and had to really work to get 14mpg. Meanwhile, my '02 7.3 Powerstroke with 3.73 rear end and single rear wheels gets 19 to 20mpg with 345,000 miles on it!

By the way, I have an '85 F-350 I'm about to part out plus an '85 E-350 that I want to fix up. Keep 'em and drive 'em forever!

[ocnorb]

Originally Posted by ToddT58

Ocnorb, what rear end ratio did you have?

Both rigs have the original 3.54 gears.

Ive heard of guys swapping 3.07 rears from early Dodge diesel trucks into these and getting 25 mpg pretty easy.