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Turbo and N/A same engine?

Burning oil

LeroyDiesel.com
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Seems like there was a thread or atleast a mention at one time. Just brain storming and see what you guys thought.
In the quest for max MPGs would going N/A on a engine built/set up for turbo gain any MPGs. At the same time I don't want a gutless turd that can't get out of its own way so keeping the turbo could be good also.
BUT what about having both? The thought would be to use a 6.2 style intake or even the 6.5, remove the upper and fab up a dual inlet. One inlet go's to turbo the other inlet would just have a cone filter on it. It could be plumbed to recieve cooler air from outside the engine bay. The N/A inlet would need a simple one way valve to prevent pressurized air from escaping.
Under low load conditions I think it would tend to N/A. An ajustable program would also be needed and might be set according to APP input?.

This is just the very rough idea and open for any comments.
 
Right after last post some ideas hit me.
If under low load conditions the turbo is still providing positive pressure to the intake (witch is probaly normal) Could the pressure be dumped via a valve into the exhaust system? Would that even be benificial? Would it help move exhaust gasses out or hinder them? Would it lower emisions?

Under low load conditions Just cruising at 55-65 mph the turbo really isint needed so N/Aing at those times might be good?? what say you?
 
I think GM tried dumping most turbine drive pressure with wastegate with the vac controls at light throttle highway rpm's. Kennedy favored keeping the vac system vs the TM for this reason iirc. And or a variable turbo might be good. Would think you would need two fuel maps.

The cool pretend electric clutched blower of Mad Max's car idea might work if operable. Maybe solenoids to open bypasses turbine cut out and intake too for cruising?
 
I don't think wasting or pumping air into exhaust would really help emission except dilute exhaust gasses. It would not improve overall mass of polution. I am pretty sure you have to control the combustion temps and oxygen mix to control the NOX chemistry.
 
The OEM factory Wastgate system wouldn't be that bad if it wasn't for all the problems.......Vac pump, WG solenoid, plastic lines cracking, etc.

Just needs to be tweeked to hold boost when you really need it......Funny now that the tweeking (Flash/Tune/programing) is the easy part.

I actually like the factory system......and have many vac pumps to prove it!!!:eek:
 
Right after last post some ideas hit me.
If under low load conditions the turbo is still providing positive pressure to the intake (witch is probaly normal) Could the pressure be dumped via a valve into the exhaust system? Would that even be benificial? Would it help move exhaust gasses out or hinder them? Would it lower emisions?

Under low load conditions Just cruising at 55-65 mph the turbo really isint needed so N/Aing at those times might be good?? what say you?

The EGR is what opens between the intake and the exhaust and what way does gas flow? Hint: The drive pressure ratio for a turbo is always higher than the intake pressure it generates. You may as well use the air the turbo generates otherwise you are not getting any benefit from the exhaust restriction and heat the turbo uses.

Best thing to do is go with a bigger turbo. Opening a wastegate at cruise is not efficient. Just look at how small of a hole the wastegate is and how restrictive it has to be just by small size. The ATT I have will drop off most boost just by taking your foot off the throttle. The GM3 would keep 6 PSI of boost no matter what by RPM alone.

I suggest one could slip the bigger turbo into the powerband easy by using a high stall torque converter and a triple disc lockup clutch. Slip it to the powerband and then lock the converter for cruise or when it locking will not drop below the powerband.

I happen to have the 6.2 military precups. This may improve MPG while leaving turbo power available with the ATT. It does restrict the available power vs. turbo precups. With the different fuel I am starting to get closer to the 6.2 NA MPG running the old 'sulfur unlimited' diesel, but, I have exceeded the MPG of a normal 6.5.

Exhaust work including custom headers and turbo relocated could help with exhaust restrictions. Wrapping the manifolds and crossover can help. Heat in the exhaust to run the turbo and after the turbo to keep it flowing hot.

Variable turbos like the Duramax has would be the next place to look. They get near 6.2 MPG with 3x the power.
 
The main reason NA gets better MPG is the lack of a turbo in the exhaust stream, the lack of the crossover combining into the passenger manifold.

So only way to get NA MPG is to eliminate the turbo and its type of manifolds as a restriction. A center mount system is a more efficient design, so put a large turbo on center mount and would likely beat a side mount in MPG. Or install a large turbo under the truck like Cody had done with his Camaro originally, after the NA headers combine with a Y pipe. Or use a supercharger with a clutch, then can go total header mount exhaust.
 
There was 6.5 NA as well though with the same heads as the turbo version. And some guys had the 6.5 NA that was about the same economy as the older 6.2 NA.
 
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