a lot of people keep asking me this, and it was mainy i think cause the turbos were cheap and it sounds cool, but have a read of this, it makes a lot of sense and actually gives reson for twin turbo being better for a ROAD car than a single turbo

from www.autospeed.com

Twin Turbos
For mega-horsepower turbocharged road cars, it is normal to pull off the factory turbo unit and replace it with a monster turbo. While this gives smooth boost response and excellent top-end torque, the trade-off is a loss of low-range (and possibly even mid-range) torque and an accompanying loss of transient response. So yeah, a single big turbo will be great for cutting loose at over about 120 km/h, but at normal urban speeds it's likely it won't have the low-down boost to produce much torque. You might find it a bit embarrassing to own a genuine 500hp car if you can't keep up with 300hp cars in everyday traffic...

Take a look at any factory-produced high-horsepower turbocar and you'll see there's always more than one turbo under the lid. This isn't by chance - they're made this way to achieve much better low-down torque and turbo response, while still retaining similar top end to a massive single turbo installation. So if you ever decide you want to get lotsa power from a new turbo system, ask yourself if there's enough room to fit two (or more) turbos.

so how do you like them apples

it's true what it says, i remember my bro's starion (a little old skool but still) it would make positive boost at 80km/h in second gear, this meant he never really used boost, cause when it arrived he was already on the speed limit, basically in the every day driving around suburban roads it was pointless, the only time he could really use it was down the occasional freeway on ramp

the tt-a12 on the other hand i found was completely diffrent, and i hope the a15 is too

anyway thats some interesting reading for ya

i can't remember asking... ...but can i have your set up...once its completed??

Yes, along those lines the new Volkswagen Bugatti, shown in public for the first time last month, has four turbos. It is supposed to go on sale later this year.

I met a guy once at some drags out the back of perth, one very cold morning (2am!) and he had a supra that used a supercharger that started at about 1000rpm i think and then a turbo that started about 1/2 way thru the rev range to the top. Aparently that way they overlapped a bit in the middle. When the supercharger was fading out, the turbo would kick in.
He had money coming outa his arse thou!

Can tou still get those turbos cheap? Even in my currency and with freight charges, it would probly still be cheap.
I am presently in the throws of designing/building a turbo a12 useing the turbo off a u11 bluebird, but two is better than one. hopefully Ill get my blower setup together soon too.
just a thought for anyone wanting to build a drawthruogh turbo set up, Im gonna use a carb off a 2.5 triumph, theese have twin side draft strombergs, half of 2.5 is perfect for a 1200. Plus my friends dad has wrecked dozens of them, and will sell me a good one for $30.

but show me any production car that has less than 3cyl feeding each turbo...

but show me how big the swept volume of each of the cylinders is,

but show me how big each of the turbos are,

but show me that you can think into it a bit better before you respond next time

What about the twin-turbo Subaru Liberty (Legacy)?

The exhaust "pulsing" is worse on 4 cylinder, this can lead to unusual behaviour, meaning you only get half the exhaust pulses to push around the turbines. But if you are using a 3 cylinder turbo, then the wheels in the turbo are designed "good enough" to resolve this problem.

Cheers,
Chris

Does this maybe explain why the new Liberty's are single turbo.....

the old setup ran exhaust into the turbos consecutively, 2 blasts into one, two into the other, and there was no noticable surging of turbos or anything like that, now with the new design running exhaust alternating between turbos, one into one, one into the other, it should be even better

so im not concerned about that

lets not discuss this like "oh well, porsche doesn't use it so it can't be good", that's not a valid point

on a side note i just watched an old video (high performance imports v.2) and was actually quite suprised at the numebr of twin turbo setups being used, i previously thought most drag cars opted for a single, but that wasnt the case, (most cars were GT-R skylines running 9-10 sec passes), but i was initially talking about suitability to a road car

i'd actually like to hear someone's opion on why it would be better to run a single turbo on a road car, other than the price of turbos obviously and the little bit of extra plumbing, im looking for something more technical


[edit] my reason being i wanted to "upgrade" (so i thought) to a single turbo in the future, but now my heart is set on the idea of twin