Our Subaru boxer engines kill our spool up time, most notably because of the very long pre-turbo exhaust tract(exhaust manifold, up pipe). To directly combat this loss of spool up we will
port and polish all 9 inlets/outlets of your 3 piece exhaust manifold. We enlarge each port to match up with the stock subaru gaskets, porting ~
6-7mm of material at the entrance/outlet of each port and then tapering down into the port. This takes out the large steps in flow and smoothes out the port to port connections. Every piece is perfect matched to eachother for optimal flow.
As far as gains, 3rd party unrelated Subaru owners typically see
~15 whp/wtq gains, most notably in the low and mid range. You should also expect to see quicker spool up time.
The GrimmSpeed HiFlow Crosspipe is an available option if you want to take it to the next step in power gains. The crosspipe is the pipe that connects the driver side exhaust manifold collector to the passenger side exhaust manifold collector. Subaru made the OEM crosspipe very small and restrictive with some very large steps in the exhaust flow path. The GrimmSpeed HiFlow Crosspipe solves all the problems of the OEM Crosspipe. With a 30% bigger bore and zero steps in the flow path, if you want optimal exhaust manifold flow, you need this pipe to achieve your goals. The pipe is constructed of 304 stainless steel flanges(most companies use polished mild steel to save on costs), thick 2" 304 stainless steel piping, and a 304 stainless steel flex joint.
You may need to tighten your turbo waste gate arm because of the higher flow that our porting and coating creates. Start by tightening the wastegate one full turn and then test where you are at. Repeat if necessary.
We also offer an optional Ceramic Coating that help combat underhood temps, prolong the life of the manifold, and will also keep the exhaust gasses hotter which in turn speeds up velocity. Coated INSIDE and OUTSIDE if you choose to get it coated. The pictures of the mani that is uncoated on the inside is just to show you what the PnP looks like.
Recap
-Creates an optimal flow path for the exhaust gas
-Expect gains in the 10-15 whp and wtq
-Optional GrimmSpeed HiFlow Exhaust Manifold Crosspipe
-Coating allows for higher gas velocity which speeds up turbo spool
-Entire powerband shifts to the left
-Direct bolt on to any 02+ Turbo Subaru
-Optional Ceramic Coating
-Keep the stock look for emissions
-Gain hp/tq without having to lose that boxer rumble
This item also available for our core exchange program. If you dont want down time you can pay the upfront core fee and get one of our exhaust manifolds, then get the core fee refunded when you return your old stock manifold.
We can also tap the exhaust manifold for your aftermarket EGT Gauge.
Exhaust Manifold Porting and Polishing: 199.99
Thermal Coating: 49.99
02-05 WRX, 04+ STi, 05+ LGT
http://www.grimmspeed.com/catalog/pr...products_id=99
06-07 WRX
http://www.grimmspeed.com/catalog/pr...roducts_id=100
Exhaust Manifold Porting and Polishg w/ GrimmSpeed HiFlow Crosspipe: 324.99
Thermal Coating: 69.99
02-05 WRX, 04+ STi, 05+ LGT
http://www.grimmspeed.com/catalog/pr...roducts_id=102
06-07
http://www.grimmspeed.com/catalog/pr...roducts_id=126
