Pelican Parts Forums - Twin Scroll 1.06 A/R GT35 and dual gated Rarlyl8 headers

Pre-mod I was running a GT3582R on GSF headers with a home made 3" dual out using a dynomax straight through 3" system. I was also running SDS with M&W CDI CoP and 55# injectors on clewett blocks.

It had horrible boost spiking and overboosting so I went for dual gated Ralrlyl8 headers to get around the poor WG pipe design on the GSF headers. I also decided to go with a larger 1.06 T4 twin scroll tubine housing for a true dual gated twin volute system. I also thought I'd upgrade the ECU to a DTA S80 with new EV14 72# injectors. It uses two MV-R 38mm gates with 1 bar spring stacks.

It must be said the larger T4 1.06 housing is huge compared to the T3 .82AR. It is an absolute pain to fit and needs extensive brackets / hangers, mount mods, exhaust mods, inlet pipe mods, tin mods etc......but it does fit, only just.

http://forums.pelicanparts.com/uploa...1361003937.jpg

DTA S80 ECU:
http://forums.pelicanparts.com/uploa...1361003968.jpg

Ralrlyl8 headers with twin Tial 38's running open screamer pipes.

http://forums.pelicanparts.com/uploa...1361004018.jpg

The 38mm exhaust ports needed opening up as the headers use large primaries with 42mm port gasket inserts. Home made dual 3" straight through exhaust (with rough as guts welding!). This dynomax muffler is perfect as the inlet is top left with a 3" straight through running to the lower right outlet with a 3" junction in the middle for the lower left. You can roll a tennis ball though it and it sounds perfect.

http://forums.pelicanparts.com/uploa...1361004186.jpg

Results:
Boost onset is slightly lazier than the smaller .82 but similar, starts showing boost at 2000rpm, 0.5bar at 2500 and 1 bar by 3000rpm in 4th, a bit later in lower gears, say 32-3300. The boost does not ramp up and hit like the smaller 0.82 housing but surprisingly responsive for a 1.06 housing. The power?, jesus the power is night and day. The pull to red line is so much stronger its jaw dropping. Still tuning the system but it would never run as hard as it does now. The other best thing is the sound.....the howl at 3000 to 4000rpm out the these headers is so delicious. Boost control - ROCK solid.

It also runs noticeable better at low injector pulse widths with the new EV14 72# injectors, much better than the old EV6 55#'ers. Note I need electrical and length adapters for them but well worth it.

Will try get some vids once its tuned. I'm delighted with this mod, although expensive, it still has a serious bottom end to it and a ballistic top end, what I had hoped out of a true twin scroll set up. Looking forward to adding ported heads etc and some bigger cams to really turn up the wick. Feels like a solid 500rwhp at 1 bar but could be more? its pulling about 65-70 out the injectors currently. Top end power feels relentless.