Topic: How do you turbocharge a mechanical injection diesel?

I know how to do this with an electronic injection motor, but how would I turbocharge a mechanical injection diesel?

I'm asking about fuel management.

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Re: How do you turbocharge a mechanical injection diesel?

Just swap out a VW ALH TDI engine and tranny . I have been running the commercialwebsite TDI Beetle for years .
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Re: How do you turbocharge a mechanical injection diesel?

rmcdaniels wrote:

I know how to do this with an electronic injection motor, but how would I turbocharge a mechanical injection diesel?

I'm asking about fuel management.


If it's a 240d/300d, DON'T. Just get a factory turbo mill with all the plumbing. Boost is a bridge too far for the NA versions; they develop piston/rod issues quickly. The factory used piston cooling oil jets and upgraded rods, and by the time you do that, you shoulda found a 300D turbo with a bum transmission for $400 and grabbed all you needed.

I don't remember the way the injection pump is boost-referenced, despite being a 8-time 300D turbo owner, because it never fails. No joke.

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Re: How do you turbocharge a mechanical injection diesel?

Type44 wrote:
rmcdaniels wrote:

I know how to do this with an electronic injection motor, but how would I turbocharge a mechanical injection diesel?

I'm asking about fuel management.


If it's a 240d/300d, DON'T. Just get a factory turbo mill with all the plumbing. Boost is a bridge too far for the NA versions; they develop piston/rod issues quickly. The factory used piston cooling oil jets and upgraded rods, and by the time you do that, you shoulda found a 300D turbo with a bum transmission for $400 and grabbed all you needed.

I don't remember the way the injection pump is boost-referenced, despite being a 8-time 300D turbo owner, because it never fails. No joke.

Nope, it's for a diesel Chevette. I know there has been at least one in Lemons, and probably more.

I found the same thing for  the 240D. That horrible race car is getting a OM617 swap out of a '85 300SD. It was so cheap from LKQ that it didn't make sense to mess with the 240 motor. It's actually sitting around here now, waiting on me to finish my Civic track toy and Targa Southland E30 Cabrio projects.

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Re: How do you turbocharge a mechanical injection diesel?

I think you should go with the scheme they use on "turbo-normalized" aircraft engines. Set a boost pressure with a mechanical waste gate and thats it. So long as your injection pump has enough fuel capacity you'll make more power. With a diesel there are so many things you don't have to worry about in comparison to a gasser.

I can assume you are looking to do 10psi or less??

Re: How do you turbocharge a mechanical injection diesel?

I was thinking 7 PSI. That's all I normally like to do on a motor that wasn't built for turbo.

Forgive my diesel stupidity; I've built a lot of turbo gas motors using EFI systems, but how do I get more fuel to mix with the more air to make the MOAR POWER??????????

In a gas motor I'd either boost reference the fuel pressure (cheapest), boost reference the injector duty cycle (less cheaper), add an injector in the TB (not going to work for diesel), or dyno-tune it with a full EFI system (least cheapest). I guess there's also MAF systems, but I've only worked with speed-density EFI systems.

If the fuel system is mechanical, then is it also intake manifold pressure referenced? I'd been assuming that mechanical meant that it did a fixed thing for a given engine speed and throttle position. If it is referenced to manifold pressure, then what's the limit? Not that I want to run 30 PSI on this thing (actually I'd love to do that if I thought that it would hold together for any length of time), but I'm curious. On a Honda I can go up to 1 BAR before I have to modify the manifold pressure sensing system, what is it on a mechanical injection diesel?

Thanks

Everybody grab your brooms, it's shenanigans!

Re: How do you turbocharge a mechanical injection diesel?

You don't want to boost reference a turbo diesel.  On a typical diesel, the engine power is controlled by the amount of fuel that you squirt in.  If you boost reference, it will create a feedback loop where it keeps injecting more fuel as it keeps spooling up.

On a diesel, turbocharging just lets you inject more fuel before it runs out of air. You either need to increase the fuel pressure, increase the size of the injectors, increase the dwell time for the injectors, or add injectors.  How you go about doing that on this particular mechanical fuel injection setup, I'm not sure.

Re: How do you turbocharge a mechanical injection diesel?

A diesel produces no vacuum so unless you have an airflow metering device there is no feedback to provide to the pump. You don't have to worry about that if its truly a mechanical injection system. They just put fuel in the cylinder and it either burns or it doesn't.

As stated above you can dump in as much fuel as you like and any that doesn't burn comes out the exhaust as soot. If you can't make soot then putting a turbo on won't do anything for you since you are already fuel limited.

You are correct that the amount of fuel is governed by pump RPM and "throttle" position.

If you can "roll some coal" then a turbo will help to reduce the smoke and give you some extra ponies too. If not you'll need to do some pump/injector mods to get your fuel delivery rate up.

Overall you don't have to worry about much of anything if you are in the 7psi range. Do a mechanical waste gate and have fun!

Re: How do you turbocharge a mechanical injection diesel?

Thanks, that makes sense. I'll just be making use of the fuel that would normally go towards making a cloud of black smoke when I accelerate.

Wow, this will be much easier than I thought it would be.

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Re: How do you turbocharge a mechanical injection diesel?

Well the Chevette at ncm I believe let a little extra oil make its way through the turbo to increase the mixture.  I think they said it was 4L in 3 Laps.  THey did have to go back to non turbo because they couldn't figure out how to supply the engine with an extra 40L of oil or so a stint.

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Re: How do you turbocharge a mechanical injection diesel?

Yeah, I was going to use a turbo with seals in it, but that does tie in to another project that I've been working on.

The current hot pit policy of no working on the car unfairly penalizes those of with a lot of blowby, bad turbo seals, of other oil-consuming issues. We have to pit to paddock unless we can run for 8 hours without topping off our oil. This has caused me to lose many races. Admittedly there may have been other issues, like a slow car that is poorly prepared and driven, but I really think it's the oil thing.

I was thinking that I'd use a BMW sump oil level sensor tied to a warning light and an oil tank with a dump truck oil cooling pump to a line to the engine oil filler. I'd automate it, but I'm reasonably sure that would go horribly wrong and end up with me oiling down vast stretches of the track, so I'd run the sensor to a dash light and wire the pump to a momentary switch. You get a low level light and hit the switch for a few seconds until it goes out.

I can't see why nobody invented this already.

Everybody grab your brooms, it's shenanigans!

Re: How do you turbocharge a mechanical injection diesel?

rmcdaniels wrote:

Yeah, I was going to use a turbo with seals in it, but that does tie in to another project that I've been working on.

The current hot pit policy of no working on the car unfairly penalizes those of with a lot of blowby, bad turbo seals, of other oil-consuming issues. We have to pit to paddock unless we can run for 8 hours without topping off our oil. This has caused me to lose many races. Admittedly there may have been other issues, like a slow car that is poorly prepared and driven, but I really think it's the oil thing.

I was thinking that I'd use a BMW sump oil level sensor tied to a warning light and an oil tank with a dump truck oil cooling pump to a line to the engine oil filler. I'd automate it, but I'm reasonably sure that would go horribly wrong and end up with me oiling down vast stretches of the track, so I'd run the sensor to a dash light and wire the pump to a momentary switch. You get a low level light and hit the switch for a few seconds until it goes out.

I can't see why nobody invented this already.


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Re: How do you turbocharge a mechanical injection diesel?

rmcdaniels wrote:

I can't see why nobody invented this already.


Somebody did. It's called a Murphygage. http://www.fwmurphy.com/products/level-devices/lr857

Re: How do you turbocharge a mechanical injection diesel?

As far as adding oil you only really need to mount a tank higher then the oil sump in the engine and the oil will flow via gravity. The valve to open and close the line from the reserve tank and the sump would be the issue. An electric one like used with an Accusump will work.