Re: [DML] what kind of turbo?

["B Benson" <delornut@xxxx>]

> Every supercharger I have seen blows the forced
> induction right through the carb or into the throttle
> body. > HOWEVER, the BAE single turbo kit and the Turbo
> Manifold Twin kit are "blow-by"; ie, the forced
> induction is blown into the intake manifold to
> supplement the air pulled into the throttle body.
> Is there a performance advantage of one approach over
> the other?

Marc Levy's response comparing his legend set up to his Island system was
interesting. I'd like to expand on it with my experiences. I designed a draw
through system similar to the BAE kits and had good experiences with it for
several years. Eventually I had to have the turbo rebuilt by a local shop
here in Minnesota as I was experiencing blue smoke in the exhaust.
Everything went fine for several more years until the blue smoke appeared
again. After another rebuild, this time by Majestic Turbo in Waco, Texas I
still had blue smoke and oil in the intake. I called a super tuner and race
prep shop in Louisiana that I knew and they suggested having the turbo
checked by Turbonetics in California as they said they'd had bad
experiences with Majestic. The oil still found its way into the intake. My
conclusion is that the oil seal just can't be made positive with a simple
rebuild kit after all these miles. With a blow through set up like the
Legend car the vacuum in the intake side of the turbo rarely exceeds 5
inches Hg. On a draw through system like mine and the BAE kit the vacuum in
the intake side of the turbo can get as high as 29 inches Hg. Without a
positive seal between the center bearing area and the compression side, that
much vacuum will, without a doubt, suck oil into the intake. I used a Rajay
turbo similar to the one BAE used and I don't belive that particular turbo
is available as a new unit any longer. These turbos are used in a variety of
aircraft and there are parts available through aviation sources but anything
connected with something that flies has the price inflated considerably.
Rebuild kits are sometimes available but Turbonetic is one of the best turbo
shops around and my problem still persisted. I've abandoned the turbo for
now and run without it but I've heard of several other single turbo cars
with a draw through setup that have the same problem. If I were to design a
system again I'd go with the blow through arrangement because of this.

Bruce Benson