Has anyone ever tried to adapt a 2 stage sequential turbo setup (example:The Borge Warner R2s) or any other sequential turbo setup on an LS motor? Its a regulated 2-stage turbocharger consists of two turbochargers of different sizes connected in series that utilize bypass regulation. One for boost at low rpm and one for high rpm, eleminating most lag. I know of one company, Sound Performance, that makes a sequential setup for the Supra. The only other applications I have seen sequentials in is the BW diesel truck one listed in the first sentence, the 2010 range rover TDv6, and one that Porshce designed on the 959 in the 80's. There's probably others, but why haven't we seen more of this style turbo set up? Looks like it this would catch on seeing that it solves lag issues and still provide seemless boost delivery throughout the entire rpm range. Any input would be greatly appreciated.

 

Biggest issues would be price and space. Would be cool to see a setup like this but with the performance the single units are doing on these trucks going with a setup like that would be just for bragging rights to me. I would do it lol.

 

My understanding is it is a good middle ground of sorts; better spool than a single big turbo, but less total output than only a big single. The smaller turbo helps get the boost going quicker, but then chokes it up top where the single alone would be better. For guys that would do something like this, it is generally not a big deal to give up some spool for better big-end performance.

 

diesels run big sequential set ups because of the boost they run at. these days 50-60 psi on a dd is not uncommon. at those boost levels with an engine that spins to 3500rpm with a big single, you'd never spool. they can run that because those engines are direct injection. the compression heats the air, then the injectors open and let fuel in. the heat from compression ignites the fuel. they can't detonate. well, they do detonate, but it's controlled. typical gas engines aren't direct injection, so they can't handle boost on that level. so there's just really no reason to run sequential set ups on boost levels gas engines generally see.

some rice rockets run sequential turbos partly because their heads are so restrictive that they need big boost to flow enough air for big numbers. remember that pressure (ie pounds per square inch of boost) is resistance of flow. also their engines are small by our standards so to spool turbo(s) big enough to feed the power they want they need help spooling. that and most people i've met that drive imports have SDS (small dick syndrome). so they get a big wing, big rims, find the biggest/craziest turbo set up they can, etc.

 

Maybe im just thinking outside the box a little too far, but is it not possible for someone to keep the big single turbo that lagged until say 3000 rpm and put a smaller turbo in sequence that produced boost from close to idle up to 3000 rpm and then switched over via a valve and let the big turbo take over whilst maintaining the same super high boost levels without a low end sacrifice. The only problem I could see is maybe a slight hesitation during switchover, but far less than what normal lag would produce. BTW, thanks for the insight so far...

 

You should pm kyle (KBRacing) and ask him to contribute to the discussion. He has been itching to build one of these setups, and knows more about it than I do.