6v92 350hp injectors / turbo

[Darkspeed]

I know its been a while since I asked about this but my 1983? Silver 6v92 (flixable) has the 9T70 injectors , TV7101 1.39 turbo , and large radiator.

Before I reinstall it I would like to bring it up to 350hp

Am I correct that I need  a TV7512 turbo with a A/R of 1.23 , and 9G90 injectors?

Do I need to check the cam?

Do I need to check the Blower? Am I looking for a bypass? How do i tell?

im guessing the turbo is this one >
Part Number   465369-5001S
Previous versions   465369-9001S, 465369-0001, 465369-1
OE number   23501978, R23501978

and injectors are > 5226410 INJECTOR ASSY., FUEL (9G90)

As always.. Thank you!

[TomC]

Bypass blower will bring you from 335hp to a full 350hp.

[Darkspeed]

Bypass blower will bring you from 335hp to a full 350hp.

Where am i looking for the bypass on the blower?

[lostagain]

Yes that is the turbo and injectors I installed in my 6V92TA. It has the mini by pass. It is located on top of the blower at the back of it at the fly wheel end. It is a cylinder a little bigger than your thumb.

Your engine will put out more heat. Your cooling system better be in good shape. Is this for a Flx bus, or an MCI ? In my 5C, I have the smaller rad blower pulley, and the bigger squirrel cages. I have to watch and manage the temperature when the weather gets hot, like above 30C, 90F. But the power is great to have. It goes as fast and hard as a loaded late model 53000 lb Prevost.

JC

[TomC]

Bypass blower is a new rear plate. It involves removing and replacing the rear plate, attaching the feed hose to the pressure side of the intake. Bypass blower will bypass just enough air to equalize the pressure on either side of the blower to allow it to "freewheel" and not take power when you're pulling. I have one on my 8V-71. Good Luck, TomC

[Darkspeed]

My radiator is a 7 pass with an 8 blade fan.

Its going in a PD4106

Anyone have a photo of the "Bypass" on the blower?

There is a bypass and a mini bypass?

Is it this?? ( not my engine )

[lostagain]

Yes it is a mini bypass.

JC

[Darkspeed]

Ok i just went out and took a photo of my engine and there in no bypass...

Is this a problem??

Should I add a bypass??

[lostagain]

You don't have to. It will run without it, as it does now. The bypass helps some, exactly how much I don't know.

JC

[Darkspeed]

so im guessing the bypass acts as a check valve sensing positive pressure above the blower from the turbo.

keeping the blower from acting as a restriction.

So if turbo pressure > spring rate then bypass, or does it mechanically allow the blower to free wheel.

If this is true and there was an available port above and below the blower you could do an inline calibrated check valve - just a thought..

[Geoff]

The by-pass releases the blower lobes so when the turbo boost is higher than the blower pressure the blower turns faster allowing the higher boost of air into the airbox.  More power, less black smoke.

--Geoff

[Darkspeed]

What is best case / worse case on the cams? I dont know what mine has... #6VF093525 8067-4423 1982?

[bevans6]

My blower also does not have a bypass valve, stock from the factory, so I see no need to add one.  As I see it, the blower is gear driven and it's speed is locked to the engine speed.  It always takes whatever air pressure is presented to it and adds its mechanical boost to that pressure, it kind of has to.  It's just a mechanical pump, after all.  It always takes a certain amount of horsepower to create that boost, and the bypass simply stalls the blower so it doesn't add boost, and so requires less horsepower to spin.  But the blower is still the gatekeeper to the engine, virtually all of the air needed to run the engine goes through the blower, and only a tiny amount bypasses through the valve.  At the end of the day I see the bypass valve as a fuel economy device.

[Utahclaimjumper]

 It also stands to reason that when the turbo pressure excedes the blower pressure, the blower is "unloaded" so it takes much less (if any) horsepower to operate.>>>Dan

[bevans6]

Actually not so. I believe.  The blower (on an 8v71, the only one I can remember the numbers for) moves around 440 cubic inches of air per revolution, or 880 CI per crank revolution since it's driven about 2:1.  880 is roughly 1.5 times the displacement of the engine, so it moves more air in than the engine can take out, and so creates a pressure in the air box.  The engine manual lists the pressure developed, which varies by RPM and flow through efficiency of the exhaust, as being between 5 psi and 8.2 psi at 2100 rpm.  That's above ambient at the intake of the blower.  If the blower is seeing 15 psi from a turbo, then the air pressure inside the air box will be 15 psi plus 5 psi, less losses due to leakage and heat.  Now why a bypass.  The bypass takes some air from inside the airbox and passes it back out to the intake side of the blower to even out the pressure.  If it can pass back all of the extra air that the blower moves in (around 300 CI per crank revolution) then it can completely unload the blower from having to move air into a restriction, and lower the load - it takes a lot of HP to spin the blower, and the load increases if you restrict the output so it has to create pressure.  My research shows that the talk about the bypass when it was introduced was efficiency - if you design the system so the turbo is matched to the blower and the bypass, it should be quite a bit more efficient and produce better power as well.  If you don't care about efficiency, a non bypass blower will produce more power, in theory, since it adds to whatever the turbo produces for that combination.  There was a bit of talk about blower longevity - unloading the blower at speed relieves load on the blower bearings, and is one reason bearings were improved over time.  Some smaller engines had been getting along with plain bushings in the aluminium end plates pre-turbo, and had to be upgraded when turbo's came along.