what makes a single turbo FD more powerful than the stock TT?? thanks for the help...

 

In the TT there is a small turbo and a bigger turbo, first turbo boost comes on quickly to about 10 psi, at about 4500 rpm the second bigger turbo takes over and the boost raises to about 13 psi, but the amount of overall airflow is small compared to a single turbo upgrade.

so the second turbo pushes a small amount of air at 13 psi compared to a single turbo upgrade at the same psi, there for it makes more power.


the only draw back is that it takes longer for the turbo boost to build up in the larger single turbos, ie T88
in short distances, the stock set up will blow out a 800 HP T88, but when his boost comes on, we have lift off folks.

 

The stock system has two of the same turbos (or very nearly so). They are both Hitachi HT-12s. Below 4500 RPM, all the intake and exhaust flows through just one of them. Above 4500 RPM, the other one comes online, and they run in parallel, with half the intake and exhaust going through each. They are setup in this sequential manner to have good turbo response down low, and still flow enough to make power at high RPM.

One big turbo is bigger than the two stock turbos put together. Bigger turbos generally make more peak power at the expense of losing some power low in the RPM range. Some of the newer singles spool up nearly as fast as the stock sequential system, however, so going for a single turbo doesn't necessarily mean that you will be giving up all low-end power. No one bothers switching to a single turbo unless they want to make more power (or reduce the system complexity), so single turbos generally make more power.

You can also upgrade the twins to flow more than stock.

-Max