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Discussion Starter #1 (Edited)
i wish to convert mt spirit r/t to twin turbo status. i'm not concerned about the work but more about the effectiveness. 1: is it effective 2 which cylinders would i combine. It looks like the middle ones hit at the same time and the outer ones hit at the same time I was thinking two separate manifolds, each connected to a set of two cylinders firing at the same time or the other way.
the only other twin turbo four ive heard of is ford focus rs rally type car from europe
 

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yes, please read that thread, and search for the several others that are here :)
fyi, the focus rs is NOT twin turbo. to my knowledge there has never been a production twin turbo 4 cyl, and for good reason; its just too much expense and effort to achieve the same thing you get with a properly sized single.
 

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Finding the propper turbo to do the job would be a PITA itself. A mitsu's turbine housing is far too small for good power or even decent power, a Garrett takes too long to spool...

Good luck man, I would suggest just putting a hybrid turbo on it.
 

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You could always do a two-stage twin setup. instead of running a turbo per 2 cylinders, you've one small, low-lag turbo and one larger, laggy but powerful turbo both feeding all 4 cylinders. The small one spools first and, as boost builds, spins the larger one. That's how the FD RX-7 does it :)
 

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hey I don't know Dubletrouoble ran 12's on street tires right of the bat itha twin turbo 8v, and there are some good pionts to doing a twin turbo if you read that tread you will notice that there are lots of opinions, anyways I belive you would want your pipes to run like this--- cyl. 1-4 to one turbo and 2-3 to the other you want cyl to fire 180* to each other and the firing order is 1-3-4-2 the bigist problem I see is forming a manifold to seperate the two turbos, if your going to twin turbo, seqencial turboing would be easier, but I was going to try and run two garrets on a 16v
 

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well what it comes down to is what you have to work with. if you have two small turbos, lots of spare piping, a welder, lots of free time, the skills to use it all, and not alot of money, then yeah, twins can be made to work as well as a properly sized single.
would anyone with half a brain pay to have it done? no.
 

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sequencial turbo's have never really proved to help a car enough to be worth it.
You cant show me a car that makes more hp for less $ on a sequencial then a twin or single.
Usually in sequencial setups there is a big dead spot also between the 2 turbo's spooling. The evo in europe had to compete against a sequentially turbocharged subaru that made 300 whp.......and the evo still whipped it through any gear. Might have lost the 1/4 just because of pure top end power, but it would roll through any gear over a second faster (had better gearing but...)
 

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Sequential turbos have their place, usually in engines with very very broad rpm ranges.

A friend of mine has a TT rx7, and when the air is diverted over to the 2nd turbo, there is only a drop of 2psi of boost for a split second, so it goes 10psi, 8, then back to 10psi. Its seamless and produces good lower speed power for drivability without holding back at higher rpms, its more like a VGT.

Of course, if all you're looking for is the big HP numbers, then one turbo is the way to do it, but what about all that great 'under the curve...'
 
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