I haven't looked at them for a while but I think on one turbo the wastegate flapper is on the manifold rather than integral to the turbo.

I'm pretty sure 120fly said the front turbo from the twinturbo rotor was the one to use... I cant remember exactly what or why

Sigma turbo's have the carbon seal standard, it's the set up I use. P.S sorry about the faces, my boy is 'helping' me!

Some sleuthing revealed THIS

I've got a nice fuzzy feeling that the RX7's do have carbon seals.

The turbos are both Hitachi HT-12's. One has a 51mm 9 blade compressor and the other a 57mm 10 blade compressor wheel.

I can't seem to find any datasheets though but I reckon these might be worth a play, especially since we're talking low cost here.

Here is another budget buildup.

ive also heard that the rx7 turbos are carbon sealed

Ok to dig up the suck thru tpoic again - who knows which (factory) turbo was released with an in-built carbon seal?

I have a pair of RX7 13B twin turbos and rumor has it that they have carbon seals... The big one looks like it'd go nicely on an A12.

These are cheap as on ebay - nobody wants them (I got them with a motor I bought for my RX2 and I didn't want them either )

I'll try and get some data on them...

Yep Thats what I wanted to see!! Brilliant & so simple..

here you can see how the J-pipe bolts to the block for support:

haha looks like i might just be a sucker for buying buggered turbos then. What you said does make sense. Just make sure you buy a good turbo that spins freely i guess. Whats the most fuel pressure people have run on a needle and seat and what carb? As a budget approach running standard 7psi boost would there be a carb/ needle and seat cabable of holding 10psi fuel pressure negating the need for expensive rising rate regulators and fuel pumps/return line etc in a blow through design. If a new gasket kit is put through the carb and sufaces are flat they should seal ok with just a hat and lowish boost.