AHarada

iTrader: (25)

This is just something to stir up thought and see what others think.

I read somewhere on the internetz that modified (bored out) TD-04 09B turbo exhaust housings will fit our stock HT12 turbos. So let's say I built a custom manifold with a runner from each rotor into a flange that is fitted with a TD04-09B exhaust housing and HT12 turbo. A custom downpipe would need to be fabbed, but there would be very little exhaust restriction like our stock setup. A custom Y-pipe would need to be fabbed also, but one with less bends than our stock Ypipe could be possible.

I'm not too sure if the TD-04 09B exhaust housing uses an internal wastegate though, but it probably does. Let's just say for this discussion that it doesn't and an external wastegate was tied into our custom manifold.

We could expect much better spool than regular nonseq. since our exhaust would have much better flow. Maybe our whole powerband could be better since our exhaust flow and charge air flow could theoretically be much better.

Monkman33

iTrader: (28)

there is no point in using upgraded twins in a non sequential manner.

Single will net you better results all around if you do not go the sequential route.

BC-FD3S

iTrader: (2)

I love how everyone always says go single. Single is not always better. Slow spool, shitty low end and peaky top end. The last car I built up was a R32 GTR. Fully forged engine with twin GT2850-5's. This car out spooled, out powered and pulled on EVERY other single turbo GTR in the area. The powerband was fantastic too... no abrupt come on of power, nice and smooth but still powerful. This car dyno'ed 630 to the wheels at 1.5 bar, and kept pulling until redline. 1 bar at 3300 rpm, wheras a T-88 or somthing like that would have spooled well into the 4000rpm zone.

It may be on a different car, but the concept is exactly the same. Two smaller turbos will spool much faster, and flow the same amount as a big single in the top end.

TT ftw.

Dudemaaanownsanrx7

iTrader: (23)

the complexity and cost of a twin setup like this really doesnt make it a very appealing route for most people to take. There was one guy on here that did a twin setup using to4's i believe. seemed like he had pretty good results. its been awhile since i read it though. There are alot of BB single turbos that spool quite quickly with a very good topend. like the gt35.

I dont know if 2 turbos always spool faster and flow the same, i've never experimented with it, and i havent seen alot of people that have. But it would be interesting to see more results of people that have tried.