I know this question probably been answered before but I know people said that twin turbos have almost instant and a larger single have more torque, but takes longer to spool. My question is how can you make a larger turbo spool quicker? My car will be mostly a street car and I don't know if I'll have monte fun with more torque or the instant boost

 

I don't think you'll find the night/day difference in spool as many say. A modern properly sized single with the right hotside, and cam will go a long way towards reducing lag.

 

That blanket statement is a common myth or misnomer if you will, you have to have a bigger motor or go real small on the twins to get the response a single would have on the same setup. Of course there are factors to both setups as far as design goes, but generally feeding one turbine with the entire motor is more responsive than feeding two turbines and splitting the motor in half. In practical application its much easier to run more power and have more rpm range up top with twins but you may be sacrificing low end, depending on the application.

For example, say your goal is 800hp and you know a single 70mm turbine with a .96ar housing will do that on your engine. Now lets say you wanted to make the same power goal on twins. To get the twins to have the same response and spool or better than that single you would have to get two turbo's that support around 400hp each which would be much smaller turbos than you would think. Would need around 45mm turbines with .43ar's to have the same low end response or better than the larger single. But when you do that now you don't have the room up top that twins tend to have.

Like Mnlx said a modern more efficient wheel turbo that is properly sized for the application would be the best way to maximize transient response and have quicker spool times and generally speaking that means getting the smallest turbo you possibly can and still support the max power and rpm range you want. The two ends of the spectrum are rather easy to do playing with turbine size and the ar of the turbine housing. You can on the small side and get wicked low end torque and spool but choke out power at higher rpms. Or go larger and have gobbs of top end power but make less torque and have less response. Its trickier to size a turbo to get the best balance of both and usually takes some trial and error.

 

Due to so many sizes and options ? It's hardly fact . Although true . Yea confusing ? Higher comp brings on boost . Or more the point the transition between off and on boost is closer . Turbo threshold and tune assists big time .