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Potentially a silly subject, but thought I'd ask.
So if your not too busy...something to ponder.

Has anyone heard of the concept of adding a second turbo to a SAAB? I'm sure it's not a new idea considering some Toyota's, and Mazda's I've seen. But one can only wonder what the potential for the increased responsiveness.

I considered the concept of the recent Viggen One-pass "Intercooler" I just added to my 97 900T. It would seem that the device is actually an "Aftercooler."

What if one were to have a turbo placed before and after the intercooler? But another exhaust source might be needed to power up the second turbo ....or maybe not.

Further research helped me conclude that the term Intercooler was originally developed due the location of where the device was placed; between twin turbo's on aircrafts to cool the the output charge of the 1st turbo.
 

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I thought that most engines with twin turbos were V6 or V8 where there was a turbo for each bank of cylinders. The extra responsiveness was down to their being two turbos each physically smaller than a single turbo would need to be.
 

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I believe sgould is correct. Certainly, all of the twin-turbo setups I've ever run across have been in engines with at least 6 cylinders. A friend of mine here in town has a very nice-looking Saab 9-5 V6 which he's put considerable money and effort into, and he's been investigating what it would take to convert his asymmetrically turbocharged engine to a symmetric twin turbo setup. Personally, I doubt he'll be able to work it, but if he does, I might have to consider changing Saabs.....
 

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My understanding of the principal of twin turbos is a small one with a swift spool-up for lower revs and a larger turbo kicking in later - thereby reducing lag and maintaining boost thro'out the rev range
 

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There are symetrical twin turbos, as stated above, one for each bank of cylinders. There are also the sequential setups as you refer to that have both a small and a large turbo. The smaller one spools up quickly and provides low end boost and the as the bigger one spools up, gives big top end boost.
 

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It would take lot of effort to make a twin turbo setup work on a Saab.

There will have to be custom headers to lead the exhaust gasses to both turbo's, new custom made oil lines, coolant lines, vacuum lines connecting to the selenoid valve, mounting bracket, intercooler hoses and of course a remapped ECU to match the completely different airflow.

If it's responsiveness you're after, it might be cheaper to tune a 2.3 NA engine like Meatball did.

One of the reasons Saab fitted a single turbocharger on the V6 was to reduce the amount of heat under the hood. Two turbochargers would create a lot more heat.

Originally posted by DC_SAAB:
[qb]Potentially a silly subject, but thought I'd ask.
So if your not too busy...something to ponder. [/qb][/b]
Silly subject? Maybe.... but I was not too busy, so I had the time to ponder
 

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I'm not sure of the details but didn't Maserati or someone combine a turbo and supercharger to get over the spool up lag from the turbo?

It might also be easier to plumb in a supercharger, since it is more mechanical to an existing system than another turbo?
But, to be honest I'm not an engineer!!!
 

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Don't know about Maserati, but, Lancia certainley did with the Group B Rallye 037 and then on the awesome Grooup B Delta S4.
 

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Supercharging would seem to be the easier option to add; doesn't need cooling or an oil supply and runs off the crank.

I might be wrong but wouldn't the extra airflow etc created by a supercharger be automatically accounted for by all the electronics in the engine managment?

Skiddins
 

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Originally posted by aeropilot:
[qb]Don't know about Maserati, but, Lancia certainley did with the Group B Rallye 037 and then on the awesome Grooup B Delta S4. [/qb][/b]
I'm sure you're right about the Delta S4 but I thought the 037 was just supercharged, like the Beta Volumex? Could be mistaken though...
 

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I have driven a Subaru Legacy GTB with the 4 cylinder boxer engine and sequential turbos.

The result - less low down performance, ballistic top end. I'd stiuck to one chunky turbo and keep that great Saab midrange.

Oh, when I bought the Saab, it was a **** up between a GTB and an Aero. Enough said!
 
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