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Single Turbo with SU's?


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I'm not a big fan of blown carburator cars (mostly because they never seem to work entirely great and are a bitch to tune).

But i was thinking today, the SU's are not like your standard carb, since they meter the air as it comes in and add fuel accordingly, their almost (in theory) like a fuel injected car.

You guys think i'd be possible to take a small turbo, maybe one from a 300zx Twin turbo (just one), and split it into two pipes and direct it thru the SU's?

Just bored and thinking about different things. Would it work (moderate boost maybe 8psi). What gains (hp) you think you would get? Too hard to do? (i'm not thinking so).

What do ya think?

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Do it the other way. Suck through the SUs into the turbo. British cars always sucked through the carbs with their superchargers. That way you don't need to pressure seal the carb bodies.

All theoretical, of course.

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Here's a turbo tom 2-barrel setup (not an su, but...):


Most of the turbos that involve SUs were a single draw through. I gather it's more difficult to get them to work under high pressure than under high vacuum. There was a member at Hybridz that claimed to have seen a turbo S30 with dual SUs on it, blow through style, but he wasn't able to talk to the owner about it much, and like a bigfoot sighting, no pictures were forthcoming. (http://forums.hybridz.org/showthread.php?t=114661)If you look for pictures of the crown turbo kits, you'll see what the SU kits looked like.


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Interesting, i'll check it out.

So i just read that article, it ditched one SU and then just used one? Am i looking at that right? How could one provide enough fuel? Weird...

Veritech-z, that hybridz thread is really good. Thanks for posting it. After reading that, it's a dead issue as far as i'm concerned.

Oh well...

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I'm sure the kit came with a new needle that would change the fuel metering. Also, I talked to a guy at a Mini cooper performance shop once, and he said they usually used the Jaguar 2" SUs for turbo (ours were 1 3/4"). They would just slap them on and not change anything, but you have to think that the Mini had like a 1.3L engine, so it might have been just luck that they could bolt them on that way. What's interesting to me is that the carb in that literature appears to be a flat top SU...go figure.

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  • 1 year later...

I had a Crown turbo kit in the 70's on my 72 using the single SU.

Technology was not too great. Tended to vapor lock in heat. The turbo barely had adequate oil feed, resulting in re-sealing the turbo a few times...Garret RAJAY turbo. THere was a beer tapper style water injection available, too. Ran Venolia forged pistons. Copper "O ringed" the head, with metal head gasket.

The trick was how to use lugging to your advantage....By starting out at a higher gear, lagging caused more heat and a kick in the pants jolt

Use to blow off Road Runners, 440's 442's, GTO's, etc.

Corvairs also used similar Crown set-ups...

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