How hard/easy is twin turboing a scoob? Just wondering what is required to do it, is it possible to get a downpipe custom made to connect from the first turbos exhaust housing and then connect it onto the second turbo? Or am I just dreaming LOL

 

I'm sure some of the earlier Legacies were twin turbos so it must be possible, but if it was worth it everyone would do it.

 

Have a full STD manifold system twin turbo of a Lego both turbos are very good condition

 

Is it worth it though? Are both turbos the same? Or one smaller? I was thinking about small td04 turbo that would boost and chatterring away at 3000k rpm, and then you have a big 20g turbo coming in around 3.5-4k?

 

My Wife drives a Legacy B4 RSK and that's a twin turbo, the only benefit is slightly more low range torque than the equivalent single turbo engine in an import STi of the same age. Downsides are the dreaded valley of death as it pauses for breath at 4k rpm, more complicated pipework, it feels like it suffers from worse heat soak than my old classic and they are more difficult to modify. Having said all that, even though it's no faster than a single turbo it is a sweet engine with bags of character.

 

Hmmm interestingg, need to drive one to see what it feels like

 

Seriously mate stick to single. Twins are a nightmare.

 

Sequential twin turbo is a good idea, gives you low down grunt and drivability aswell as top end power. But the complexity means it would be a nightmare to swap from a leggy into an imp unless you were running the turbos in parallel in which case your much better off with a decent modern single.

Even subaru gave up with sequential TT when the twin scrolls came about.

As a standard car, the TT leggy can be really good as a daily drive .... but the most you'll see out of a tuned one is about 330bhp (not great from 280 as standard).

 

Oh ok hmm, well I was thinking for example a td04 on one side and a td05 20g on other side, how would that work? Would it work well together?

 

Lol challenge accepted

 

Not really if you use the tt system in the same way as subaru did.

The two turbos are essentially the same size (quite small), but at below 4000rpm (ish) theres valves in the intake and exhaust that block off one turbo, therefore pushing all exhaust gas through the one little turbo and giving great low down torque.

When the revs rise and the one small turbo would otherwise become a restriction, the valves open and the two turbos work together.

The hole in the torque curve, known as the "valley of death", is the energy being taken out of the exhaust to spool the secondary turbo.

Considering how laggy a tdo520g is on a standard 2litre (****e!), running it from essentially 1 bank (1 litre) just wouldnt work.

Think what youve got to consider is that turbos are a compromise! If you want high end power, you sacrifice low down drivability! Which is why a drivable 400bhp is real world quicker than a strung out 600bhp, Thats just the way it is! However as turbos have evolved, that compromise of low down and top end has got better and better to the point where you can now buy a single scroll single turbo, that drives well on the road but makes 500bhp.

Sequential TT setups are out there and working well though .... the veyron wouldnt drive so well or go as fast without it, but theres a hole load of drive by wire shenanigans going on in there which wouldnt be easy to copy without a massive budget.

 

I don't think it's worth the bother really,there is a lot of big powered cars that change from twin to single turbo but I don't recall any going the opposite way there must be a reason for this,but if its something you want to give a try go for it but I would get a drive in a twin turbo leggy to see if the driving experience is what you want.SJ.