Single Scroll vs Twin Scroll?

[Th3Franz]

Th3Franz, did you move here recently? Looking forward to see your car some day. There are a few of us in the Bay area now.

 

@Unclemat - Underdog went with a 1.5xtr-ts, I think he said he should have just done a 1.5xtr. So maybe talk with him a little before proceeding with your plan.

 

Yeah I recently moved to the bay area. Living in an apartment so still figuring out where I can go to wrench on the LGT.

 

Unclemat, I have the rear o2 disabled and AF3 zero'd out. I see AFR oscillate a little bit, but I think that's the nature of twin scroll and a long exhaust path to the sensor. Cobb has an AFR smoothing table that I haven't played around with yet but that might help too. If I wasn't logging the car I wouldn't notice. I'd say it's only a few tenths it's oscillating.

 

The twin scroll EFR7163 seems to spool faster than the single scroll DOM1.5XTR 10cm I had.

[Underdog]

The reason I recommend single vs. twinscroll is because I feel the benefits do not justify the extra cost, limited selection for parts, etc. Of course there will be instances where someone can get TS parts for a deal, or they may already have the main components on the car, or money is no concern, so this is a generalized recommendation I make for someone who is just considering SS/TS for the first time.

 

All that being said, I am happy with the 1.5XTR TS. It does seem to spool up more quickly the single scroll variant. Unfortunately I have yet to put the car on the dyno for calibration because 1) I need to pull the DCCD and check a bearing, and 2) my AQ1 datalogger is out for repair, and I want to datalog the pressure and temp delta across the STI TMIC while on the dyno.

 

I currently have the rear O2 in place but will likely remove & plug, and zero out the AF3 comp/limits. I am also going to tweak the FP duty cycle tables so pump voltage never drops below 6V. I swapped the FPR assembly for the pre-07 STI unit. Finally, the fuel pressure and WBO2 will be monitored via the orphaned TGV sensor inputs on the ECU.

[KGB]

Hi Th3Franz, Rhitter, guys,

welcome to the Bay Area Th3Franz!

Would be great to do a get-together sometime in July/August when my build is complete -

YimiSport in LA is putting together a 7163TS on a custom built motor for my 06 OBXT.

(prior to this I had EFR 6258 - awesome spool, but wanted "more" - jumped to far to 7163SS - lethargic spool but crazy/scary power - blew my built motor.

Hope 7163TS will hit the sweet spot

FYI; mine is a 5EAT (one of a kind custom built for me by Automatic God

aka HexMods.)

 

PM anytime.

[Th3Franz]

Hi Th3Franz, Rhitter, guys,

welcome to the Bay Area Th3Franz!

Would be great to do a get-together sometime in July/August when my build is complete -

YimiSport in LA is putting together a 7163TS on a custom built motor for my 06 OBXT.

(prior to this I had EFR 6258 - awesome spool, but wanted "more" - jumped to far to 7163SS - lethargic spool but crazy/scary power - blew my built motor.

Hope 7163TS will hit the sweet spot

FYI; mine is a 5EAT (one of a kind custom built for me by Automatic God

aka HexMods.)

 

PM anytime.

 

Hey, thanks. I think you'll love the 7163TS. I have 272 cams with my built engine so sometimes I wish had a little more top end, but I still need to try preloading my wastegate actuator more and see if the car makes more boost in the upper revs. Boost can be a sign of restriction, so the top end is breathing nicely at least. Is Yimisport making a custom manifold for you or what route are you going?

[KGB]

Quick update - my TS7163 motor puts down 380whp in Cal 91 -

not bad at all considering its a 5EAT.

Instaling Maddad mufflers next to quiet things down and then e85 tune...

[MTBwrench]

Quick update - my TS7163 motor puts down 380whp in Cal 91 -

not bad at all considering its a 5EAT.

Instaling Maddad mufflers next to quiet things down and then e85 tune...

 

Hows it holding up?

[JazzAvi8r]

curious about the 5EAT holding at that power as well

 

side note: before I got in to the Subaru world, I was a die hard Toyota guy with a built MR2. the stock USDM gen2 3sgte comes with a true twin scroll setup -- albeit, a tiny CT26 turbo. Most MR2 guys tend to stick with the twin scroll setup since both the intake runners and the exhaust is setup that way from the factory. Once I made the switch to the JDM gen3 motor, the intake runners were no longer twin scroll yet I still wanted to keep my twin scroll exhaust setup (now on a GT3071). I didn't have an appreciable difference from the twin scroll GT3071 from the single scroll GT28RS. After upgrading the internals, fuel, and going standalone, I went to a single scroll 3470 top mount setup and pushed 662rwhp at 26psi. I was still a twin scroll fanboy and was offered a killer deal on a GT35R twin scroll setup, so I swapped in favor of that. I then pushed 659rwhp @ 25psi -BUT- that power came in about 200rpm later.

 

bottom line, i'm still a twin scroll fan boy, but the common sense in me says it's just not worth the money unless you are trying super hard to get every last possible advantage out of your motor. If I were building an 800+ awhp monster, then I would likely go TS; if it's my daily, I'd stick with the economy boost on a solid tune!