Brainstorm session Turbo and N/A together

[Will L.]

There were some with the same basic set up, bu did not use a turbo. It would use the blower until near top rpm, the go n/a for the last 200-250 rpm. Thinking about it Only remember that set up on equipment, not trucks.

 

[Burning oil]

Oddly enough manual was where it was supposed to be so here ya go.

Cheers
Nobby

View attachment 39722

Thanks, Im still not grasping the theory though. Is it bypassing boosted air to the air filter? Can you explain in basic terms.

 

[schiker]

A blower has to out pump the engine pump to build pressure in the intake. So it is constantly pumping more air than the engine can pump thus having intake pressure. But the big draw back is as RPM's increase it requires more and more power to pump larger volumes of air ahead of engine.

It doesn't require that much power to run a 10 cfm air pump at 1 psi but much more to run a 30 cfm pump at 4 psi.

Couple that with the fact the turbo can start pressurizing the intake efficiently as heat energy produces drive pressure. So once air pressure in the intake after the blower was reached it popped off and allowed the blower to free wheel some by not trying add more pressure it just pumped the air through kinda freewheeling pump wise with the flow of air through the intake allowing the turbo to provide the intake boost.

A friend told me once some fire trucks still have a turbo and blower to make acceleration power. Come to think of it I haven't seen many fire trucks belching smoke and I figure the drivers are pedal down. I have always assumed they had some type of mechanism like that.

 

[schiker]

I have wondered about possible future "CVT" crank driven blowers.

 

[Burning oil]

OK Im slow sometimes, but just to make sure I understand. It regulates pressure so the blower provides just alittle more than the engine needs instead of alot more than it needs???

 

[schiker]

Yeah, kinda sorta like a blower waste gate. Wasting off blower pressure but not turbo pressure.

 

[schiker]

Sorry you probably understand the operation of a pop off valve or waste gate. So let me say it differently.

Its a compound system. Atmosphere is pressurized by the turbo and again by the blower to the engine intake.

At low rpm and load the turbo doesn't add pressure the blower does as its over pumping the engine. It pulls air through the turbo compressor.

Once the turbo adds some boost the blower adds more pressure. But the blower is not efficient pumping a lot of air with large final pressure.

Blowers over pump the engine and at idle and low rpm they have pumping losses such that they don't use too much power to be driven. But as RPM rise they consume more power off the crank. The turbo is opposite as rpm rise (with load and more fuel) they make more efficient boost.

So once a certain pressure is attained at the engine intake the blower gate would open and allow the air to recirculate from after the blower to before the blower.

With the valve open the blower wasn't pressurizing the air it was like a pump with little pressure rise and or a recirculating loop which doesn't take as much power to be driven. It lessened the parasitic loss off the crank of the blower.

 

[hookedup50]

Makes sense to me, but doesnt the spool valve that warwagon has do this? Or would a blower work better? Just askin cause I like the Idea of better fuel mileage and if there is a better way... Well its the point of this thread.

 

[Burning oil]

Sorry you probably understand the operation of a pop off valve or waste gate. So let me say it differently.

Its a compound system. Atmosphere is pressurized by the turbo and again by the blower to the engine intake.

At low rpm and load the turbo doesn't add pressure the blower does as its over pumping the engine. It pulls air through the turbo compressor.

Once the turbo adds some boost the blower adds more pressure. But the blower is not efficient pumping a lot of air with large final pressure.

Blowers over pump the engine and at idle and low rpm they have pumping losses such that they don't use too much power to be driven. But as RPM rise they consume more power off the crank. The turbo is opposite as rpm rise (with load and more fuel) they make more efficient boost.

So once a certain pressure is attained at the engine intake the blower gate would open and allow the air to recirculate from after the blower to before the blower.

With the valve open the blower wasn't pressurizing the air it was like a pump with little pressure rise and or a recirculating loop which doesn't take as much power to be driven. It lessened the parasitic loss off the crank of the blower.

Not sure what happend to my reply? I relied this AM. Anyway thanks I got it now. Turbo and a blower..I bet thats an expensive combo on an engine.