Boost controllers and blow off valves

[Diesel Fly]

OK so most of my turbo knowledge does not revolve around diesels. My experience with other turbos (cars and aircraft) has been with wastegated set ups so that the max boost and how quickly boost comes on can be controlled. So I'm not familiar with the fuel quantity being the "control" for PSI of boost. I think I'd feel a lot better having a wastgate that can dump unwanted boost based on the max PSI of boost wanted and/or egt temp.

It just seems like it would be nice to be able to just stand on the throttle and not have to worry about letting off, while a "brain" worries about max boost/egt.

One could also feasably program different settings for towing, economy, etc. Is this just an impossiblity with IDIs because there's no real way to control fuel flow other than with your foot? How critical is fuel mixture and what is a common F/A ratio for an IDI? Do the temps spike as they get lean (just like a gasser)? How does the momentary drop in RPM from shifting (and the related closing of the throttle) get handled vs the boost that has been built up?

I'm just full of turbo questions today

 

[tonkadoctor]

OK so most of my turbo knowledge does not revolve around diesels. My experience with other turbos (cars and aircraft) has been with wastegated set ups so that the max boost and how quickly boost comes on can be controlled. So I'm not familiar with the fuel quantity being the "control" for PSI of boost. I think I'd feel a lot better having a wastgate that can dump unwanted boost based on the max PSI of boost wanted and/or egt temp.

It just seems like it would be nice to be able to just stand on the throttle and not have to worry about letting off, while a "brain" worries about max boost/egt.

One could also feasably program different settings for towing, economy, etc. Is this just an impossiblity with IDIs because there's no real way to control fuel flow other than with your foot? How critical is fuel mixture and what is a common F/A ratio for an IDI? Do the temps spike as they get lean (just like a gasser)? How does the momentary drop in RPM from shifting (and the related closing of the throttle) get handled vs the boost that has been built up?

I'm just full of turbo questions today

Holy Moly...Nick.....Here's another possible convert fer ya. ...Sounds like you are ready for the dark side, the basement dwellers will be here soon to drag you back down with their swonking sticks.

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Diesel F/A ratio is constantly variable and when you let off the go pedal to shift etc you simply lose boost and power until you get your foot in it and the turbo spools up again.

 

[Diesel Fly]

Well, the force may be strong but I'm used to living on the edge. I've been known to run with scissors and I even juggle knives on occassion. No worries, I'd like to do this to an IDI - not have it done to me by a PSD.

 

[6 Nebraska IDIs]

Well there are wastegates that you can mount into your exhaust piping. I see them in some extreme imports.

 

[84TD]

Holy Moly...Nick.....Here's another possible convert fer ya. .

You must be registered for see images attach

Thats what I was thinking, a powerstoke would do it for you My opinion is that IDIs are for no frills simple reliability with decent power. And affordable . Once you cross into expensive computer controlled gizmos you might as well get a stroker and chip it, you will have a beast.

I am not sure if you have to keep an eye on things as much with a waste gated kit. I know on my non-waste gate I could burn the motor down on a good hill if I dont pay attention.

 

[Double-S-Diesel]

#4 in the making?
I have a 95 that could go for the right $$$.
wastegate, whats that, my 96 dont have one, although 30+ psi does the turbo bad.
on the SD's with a waste gate most get disconnected anyhow to make more boost.
even when we put the b1 on the goat, they ask do ya want to pay 450 for a wastegated housing, or 150 for a non, guess what we put on.
Nick

 

[Agnem]

Well it wouldn't be hard to make such a thing. You'd need a stepper motor with a lead screw, a throttle pedal from a PSD, and a stepper motor controller circuit with a feedback loop. You could use a stock FIPL sensor for the feedback. Once you had the drive by wire in place, you could tap into the pyrometer with an op amp, and program your controller to let off the throttle if the temps get too high.

 

[f-two-fiddy]

I've thought about this also. It'd be easy to do, and would probably help a lot with a bolt action rig.

I seem to lose all my boost while shifting. And with a 500 rpm drop between gears, sometimes it takes 2-4 seconds to get the boost back up in a usable range.

 

[JwS]

I think if you get the pump adjusted correctly, so that at full throttle your temps remain below the magic numbers. That is as long as you have a non-wastegate turbo! The turbo should compensate for the any air density changes (approximately) and maintain the same absolute pressure in the intake. This is basically why they used turbos on aircraft in WW2, they kept the power levels consistent regardless of altitude.
JwS

 

[swampdigger]

I'd kill to have computerized fuel control on an IDI. Cheaply! No PowerStrokes.

A Stanadyne DS-4 pump from a mid 90s Chev 6.5 would be a neat trick on an IDI. I'd like to see some photos side by side of the two. You can pick 'em up cheap sometimes on eBay.

The control algorithms are pretty simple it seems, as I understand:

The DS-4 has two "tach" signals it emits. One is a steady high frequency signal, and the other goes high as an injection event approaches.

When it's signaled that an injection even is approaching, the computer signal to the pump to start closing the fuel meter valve while counting the high frequency tach.

It counts the tach until the desired fuel amount is reached, and cuts power to the fuel metering solenoid. The mechanics of the pump take care of firing it off into the cylinder. Too easy!

There is also a stepper motor to set the timing dynamically.

You'd need a fly-by-wire pedal, and a few sensors to calculate injection sizes.

 

[Diesel JD]

You could never use a DS4 or Chevy DB2 pump on a Ford or IH because the pumps turn in opposite directions. How about switching the governor cover from a DS4 to a Ford DB2....could it work??

 

[f-two-fiddy]

Umm, no need for a puter, just get a manual controller.

For around $200 you can get the well respected Hallman controller with in cab adjustability.

http://www.boostcontroller.com/index.php?item=126&ret=http%3A%2F%2Fwww.boostcontroller.com%2Findex.php%3Fpage%3D1%26category%3D5

If you don have a wastegated turbo, a HKS BOV and controller are pretty spendy. Bu there are lots of different options including "overseas" BOV's that are very economical.

 

[payableondeath6]

Don't take these as smart @$$ questions, I truly am curious of the answers. I've been collecting parts for a remote turbo setup and am still learning.

First, why the BOV? My understanding of what a BOV does is keep the charge air from building massive pressure as it hits a closed throttle plate at instances such as shifting or letting off the throttle suddenly...so does the IDI need one without a throttle plate? If it's just a method of controlling boost then might I ask why you're curious about a BOV over a wastegate that would just let the exhaust escape pre-turbo?

On the boost controller, other than not being electronic and fancy, is there any reason why you wouldn't want to use one of the cheapo manual setups? Ebay has them for like $10 and it would seem to be a relatively accurate and easy way to dial in boost (although not as convenient as an electronic unit).

 

[Michael Fowler]

Mel,
First you dabble with the DarkSide, the next thing you are speaking in tongues! Stepper Motor, FIPL

Caution, you might get fully sucked into the DarkSide and recant ALL your IDI ways!

 

[Diesel Fly]

Well, the BOV relieves the pressure between the turbo and the inlet of the engine. On bolt action drive trains, let's say you are shifting from 2nd to 3rd and are standing on the throttle. The turbo is spooling at its max when suddenly; you let of the throttle to shift. The engine RPM falls so the engine does not suck in as much air as it was a few seconds ago. The pressure in the inlet builds up even more as the turbo continues to pump air which has nowhere to go. This (and the momentary lift of the throttle) makes the turbine slow down. You are now safely in 3rd and reapply the throttle. The turbine now has to catch up again to the increase in exhaust gasses and the engine's ability to suck more air in. This takes another few seconds.

With the BOV, the excess pressure is vented so that the turbine tends to keep its RPM up and as soon as the engine is ready for more it delivers it almost instantly. (So, less of a lag when shifting gears.)

The wastegate acts on the exhaust side of the turbine instead of the intake side. It can divert exhaust so that less of it is used to spin up the turbine. It basically controls how much of the engine's exhaust goes to the turbine vs. gets dumped down the exhaust. If I dump all of the exhaust and bypass the turbine it technically will not build any boost.

So
BOV - vents boost that is already built up in the intake
Wastegate - dumps exhaust and keeps the turbine from building up boost

I think a manual boost controller is a decent alternative. They aren’t that hard to make out of plumbing parts.