Rajay turbos

[clayb]

Carl,

I came up with a fine map, thanks. I had to learn that "ridge leading to
the mountain peak" fuel map shape the hard way, but she runs good now.
At least up to 0 psi, I blew the turbo gaskets. Old cast iron, I'm
having them resurfaced, and I have stainless gaskets instead of fiber.
Sure lost alot of power...

Although I have datalogging, I don't measure exhaust backpressure. I
could monitor EGT, for some idea of the impact of reduced back pressure,
but it wouldn't be nearly as direct.

I did learn a little about turbos. It is quite likely that a more modern
compressor, with fins cut with a progressive pitch, would be more
efficient. The Rajay is a good turbo in many respects, with excellent
bearing design, and a solid Monel turbine. But the compressor housing is
cast aluminum, not suitable for machining to fit a replacement
compressor.

The usual answer, makes more sense to replace than modify. Know anyone
who wants some good Rajays capable of 400 HP apiece?

It would be wonderful to be able to reduce exhaust back pressure, while
maintaining or even increasing boost.

> Date: Thu, 05 Oct 2000 03:15:28 -0700
> From: Carl Summers <InTech at writeme.com>
> Subject: RE: Rajay turbos
> 
> Hi Clay,
>     I realized my .cal wouldn't work with your ecu too late...I would be
> glad to forward if it will help but requires a different processor in the
> Autronic box....have you datalogged the pressure in comparison of boost vs
> back pressure vs turbo???? I truly don't know alot about turbos but after
> Turbonetics bored the inlet and changed the impeller in a project I was
> involved in, I had no idea that it could mean so much...same boost different
> backpressure was worth over 200hp on a 1200hp engine...on the dyno.....maybe
> not real world but was impressive...I understand after correcting AFR the
> EGT's were lower because of less restriction....what I don't and haven't
> understood is why with a low vs high compression engine and no blower/turbo,
> EGT's are high when the effective overlap is lowered....is it that it
> becomes more efficient and heat is energy????
> - -Carl Summers
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