Roots blower drive gear question?

[5B Steve]

    I was at a Buddy's house yesterday and he showed me something that I never thought of before or even heard of.  He as a

    4104- 1956 6V-71 non turbo.  He changed the blower drive gear to spin it 25% faster and larger air cleaner.  I could not

    believe the difference in the sound of the engine.   Sounded to me if it had a turbo on it.   I was wondering, for you guys that

   have the 6-71's and the 8-71's would this work for you?  I haven't a clue as to how much more air a turbo (C F M wise ) this

   would put out!   


   Steve 5B.......
   

   

[luvrbus]

Yup, they make 5 differrent blower gear ratios
2.6:1
2.05:1
1.95:1
2.00:1
1:85:1
Often called a poor mans turbo the 1.85:1 gear is hard to find they were used on generators operating above 10,000ft.
In the archives here you should find a discussion on the topic I remember Cole telling somebody how to do it.
Fwiw I have the 1.85:1 drive on my 8v92 TA with no smoke and plenty of power


good luck

[DaveG]

Quite an interesting bit of trivia...and useful too!

[Nellie Wilson]

Would it affect cooling... like a turbo does? Might head toward the mountains eventually, and worry about the combination of long pulls and high elevation. (Oh my kingdom for a Jake!)

Nellie Wilson

[gus]

The 4104 didn't come with a 6V71? Has he converted to an AT?

In mechanics there is never something for nothing. More compressed air, even though at low pressure, means more hear. How much more I have no idea.

It also means more fuel consumption which at sea level or below about 500' is a waste of money.

[5B Steve]

    Gus,


    Sorry typo error, it was a straight in-line 6-71

[luvrbus]

Nellie, a little more air won't add heat it will burn cleaner but add more fuel to the mix and yes more heat.

good luck

[Nellie Wilson]

Howdy Luvrbus -

I'm a little unclear on your message. "...a little more air won't add heat... and yes more heat."

S'plain?  Sounds, honestly, a project beyond my capabilities (and meager resources) but I'd still like to understand. The Wild West beckons and I might find myself in higher elevations - but I sure can't get into bigger cooling systems and all that stuff.

Thanks, Nellie

[luvrbus]

Nellie, folks change the blower drive even the go to a higher % blower on the engines for more air to make less smoke.
Leave the injectors alone and the air alone will not add heat to the engine , but most won't do that if they have more air they want larger injectors for more HP then your heat starts



good luck

[Nellie Wilson]

Aha!

So... and I'm making a huge leap here... I'm probably not gaining much without bigger injectors? And bigger injectors produce more heat? And since, hypothetically, I'll be at 4000+ ft. - and pulling big passes - I'm going to be fighting heat anyway. Sounds like the increased air (read: oxygen) is gonna get pretty much cancelled out plus I'm adding additional heat.

Sounds like a zero-sum game? Do you agree or am I missing something?

Thanks, Luvrbus

Nellie

[luvrbus]

Don't even worry about it Nellie put in a lower gear and let the black smoke roll and you will be fine

good luck

[Nellie Wilson]

Now that's a man after my own heart. Good times, black smoke and a pure heart!

Nellie

[TomC]

Any time you speed up the blower drive, it will take more horsepower to power, hence worse fuel mileage.  But it will keep the engine from smoking in high altitude-as long as you keep the same size injectors.  In a 71 series, you can bump the blower drive and run 70 injectors without a turbo.  Good Luck, TomC