Daily driving a 300whp subaru

[Bababou]

I am hopefully soon getting my 02 OBS back from its motor swap, there have been to many delays but its all back together finally at least.  The car was originally just getting a high CR EJ25 but that blew up after 6000 miles.  It was decided it would be cheaper to just do the turbo swap at that point than to start nearly from scratch on the high CR build which has been absolutely true just time consuming.  We ended up picking up a JDM EJ20X with the twinscroll TD04 HLA and EL header, added a 3 sport grimmspeed boost controller and had to go with a K&N Typhoon intake because we could not source a stock air box.  My builder is estimating it will end up just south of 300whp on 91 octane and I'm not to sure what to expect from a Subaru with those kinds of numbers.  Ive had powerful trucks and motorcycles and a few other NA subarus but never a turboed anything.  Ive been watching videos of 300+whp wrx / Sti's and most of them end up saying that it is more power than 90% of drivers should have or could handle on the street. Is 300whp really that extreme of a power level?  Are there things you should just not do to avoid damaging the car?  Stuff like launching it will eventually grenade the 5spd. 

[el_freddo]

If you’re worried about the power do a couple of track days to get to know your new power plan and how it behaves - or just drive it gently like a Sunday drive style. 

Youll probably find that you won’t play with the boost all that much - but it’s “nice” to have it on tap if/when needed.

I hope everything goes sweet once the conversion is sorted  

Cheers 

Bennie

[Bababou]

2 hours ago, el_freddo said:

If you’re worried about the power do a couple of track days to get to know your new power plan and how it behaves - or just drive it gently like a Sunday drive style. 

Youll probably find that you won’t play with the boost all that much - but it’s “nice” to have it on tap if/when needed.

I hope everything goes sweet once the conversion is sorted  

Cheers 

Bennie

I would love to hit a couple track days in this thing, not a whole lot near me that I'm aware of just yet.  I'm typically cautious trying out new upgrades just have to keep my foot out of it at first.

Thank you and me too, I'm sure it will get there just a matter of time.  The shop got it fired up last week but the timing was way off, it was back firing out the intake.  He ordered in an oscilloscope to track the signals but it didn't get delivered until he was packing up to go to the SEMA show in Vegas last week.  It would already be done had we gone with an EJ205 but oh well live and learn and enjoy the ride.  I should end up with a better end project with the EJ20X engine.  

[GeneralDisorder]

300 is no big deal. It's basically stage "2" on an STi. 400 is getting up there a bit and can be squirrelly if you aren't accustomed. About 500 is where things get a bit scary - especially if it's setup right and spools at a decent RPM. Beyond 500 you really can't use it on the street anyway so it's honestly not that much different. Also you break things.... a lot. 

I just read through that.... a 2.0 with a TD04 twin scroll?? I have never heard of a TD04 with a twin scroll. It wouldn't need to be a twin scroll with a TD04 as those tiny turbo's spool very quickly. Almost to the point that there's very little perceptible turbo lag. 

You have pictures or a web listing for this engine you got? Because if it's a TD04 I'm betting it's NOT a twin scroll, and even if it was.... that's not going to make anywhere close to 300 WHP. It's going to be more like 260 turned up to the max with that little baby turbo. 

IMO.... Sounds like this guy has no clue what he's doing. What is he using for management? 

GD

[Bababou]

13 hours ago, GeneralDisorder said:

300 is no big deal. It's basically stage "2" on an STi. 400 is getting up there a bit and can be squirrelly if you aren't accustomed. About 500 is where things get a bit scary - especially if it's setup right and spools at a decent RPM. Beyond 500 you really can't use it on the street anyway so it's honestly not that much different. Also you break things.... a lot. 

I just read through that.... a 2.0 with a TD04 twin scroll?? I have never heard of a TD04 with a twin scroll. It wouldn't need to be a twin scroll with a TD04 as those tiny turbo's spool very quickly. Almost to the point that there's very little perceptible turbo lag. 

You have pictures or a web listing for this engine you got? Because if it's a TD04 I'm betting it's NOT a twin scroll, and even if it was.... that's not going to make anywhere close to 300 WHP. It's going to be more like 260 turned up to the max with that little baby turbo. 

IMO.... Sounds like this guy has no clue what he's doing. What is he using for management? 

GD

I get the scepticism but it is in fact a twin scroll. The motor is an EJ20Y out of a JDM legacy or forester 04 to 07 I think. The turbo is a TD04 HLA 19T.  Has dual AVCS, catless uppipes. Also went with a bellmouth down pipe he made in house also catless to a 3inch straight pipe into a N1 clone exhaust.  Probably saving up for a varex muffler quickly. He swapped in a 04 wrx harness and flashing a JDM ecu, I belive its a 16 bit ecu.

I would be just fine with mid 200s so hope your right on the power number. Im looking for a car to go camp and kyack I dont need more than mid 200s for that but the na 2.5 was not getting it done.

http://m.australiancar.reviews/Subaru_EJ20X-EJ20Y_Engines.php

https://phoenix.craigslist.org/wvl/ptd/d/jdm-subaru-legacy-forester/6714347156.html

Edited November 2, 2018 by Bababou

[GeneralDisorder]

Interesting - but yeah the twin scroll just makes the turbo spool faster - the compressor wheel is still limited being it's a TD04. It's not going to make anywhere close to 300 wheel. Those engines were designed to have turbo power, but be *smooth* in there application of power. Thus the twin scroll and tiny turbo - the idea was to make them feel like a luxury car with a bigger engine - it's not a sports car engine and doesn't have the camshaft profile or the turbo for big power. 

That said, yes it will definitely be mid-200's with the right intake, exhaust and tuning. If that's the power you want, you will be happy. It won't be "fast" by today's STi standards but it will be fun.

GD

[Bababou]

5 minutes ago, GeneralDisorder said:

Interesting - but yeah the twin scroll just makes the turbo spool faster - the compressor wheel is still limited being it's a TD04. It's not going to make anywhere close to 300 wheel. Those engines were designed to have turbo power, but be *smooth* in there application of power. Thus the twin scroll and tiny turbo - the idea was to make them feel like a luxury car with a bigger engine - it's not a sports car engine and doesn't have the camshaft profile or the turbo for big power. 

That said, yes it will definitely be mid-200's with the right intake, exhaust and tuning. If that's the power you want, you will be happy. It won't be "fast" by today's STi standards but it will be fun.

GD

My mechanic told me boost will come on quicker and be smoother on the top end as well. For all the conversations he and I have had I could have miss understood where 300whp came in. What you described is exactly what I'm looking for a fun car to drive but not a monster. I have the typhoon intake and full confidence in his tuning ability. He has tuned my NA subarus for me and made surprising improvements to my 2010 2.5i impreza.

Thank you for the input and thank you even more so for not being nasty like some of the big names on other boards. 

[carfreak85]

50 minutes ago, GeneralDisorder said:

…. with the right intake, exhaust and tuning. If that's the power you want...

I would STRONGLY suggest keeping the factory filter and air box on any turbocharged Subaru.  On the modern EJ engines, the air box is not a restriction until about 400 hp.

[GeneralDisorder]

True for GC's and GD's. Not true for GR's. The GR stock MAF housing tops out around 300 wheel. That's why all the intakes sold for GR's require tuning to rescale the MAF. They are by default "big MAF" intakes or they really wouldn't do any good. 

GD

[el_freddo]

Sounds like a win win with that setup. 

Interesting about the turbo too...

Cheers 

Bennie

[Bababou]

15 hours ago, carfreak85 said:

I would STRONGLY suggest keeping the factory filter and air box on any turbocharged Subaru.  On the modern EJ engines, the air box is not a restriction until about 400 hp.

I looked around for a stock air box with no luck but would have preferred a stock one. This one is listed as being ok to use and I got it on a bit of a discount from a co worker that never got around to installing it on his 06 wrx.

[carfreak85]

ANY aftermarket intake on a GD ('02-'07) chassis WRX requires a tune which is around a $5-600 investment.  Take another look around for a stock airbox, they are literally being given away for free!

[GeneralDisorder]

1 hour ago, carfreak85 said:

ANY aftermarket intake on a GD ('02-'07) chassis WRX requires a tune which is around a $5-600 investment.  Take another look around for a stock airbox, they are literally being given away for free!

Except for the SPT one. Which was designed to be a bolt-on sold through the dealer parts department. But it's not a performance upgrade for the same reason. 

GD

[carfreak85]

1 minute ago, GeneralDisorder said:

Except for the SPT one. Which was designed to be a bolt-on sold through the dealer parts department. But it's not a performance upgrade for the same reason. 

GD

Based on everything I've read, even the SPT intake should only be installed with a tune.  Besides that, why make an intake out of cast metal?  Hello, radiant plus conductive heat into the IAT...  Literally one of the worst aftermarket intakes I've ever laid eyes on is the SPT GD intake.

[GeneralDisorder]

It's not cast - it's plastic. Just looks cast. It's junk. I've seen many running around with tunes and that's (of course) how Subaru sold and installed them at the dealer. Tuning might help, but is not strictly required. 

GD

[Bababou]

15 hours ago, carfreak85 said:

ANY aftermarket intake on a GD ('02-'07) chassis WRX requires a tune which is around a $5-600 investment.  Take another look around for a stock airbox, they are literally being given away for free!

I had my builder check with his two Subaru pack rat friends and I found a couple others and none of them had one, called on 4 different WRX's that hit junk yards all had the front ends smashed up.  When I looked online all I could find was a bottom half of the box for $180.  They may be plentiful where you are but not here.  The K&N is installed and the builder will be tuning once the car is running so no concern it wont be safe.  He just has to figure out why the timing is so far off and its on the road I don't want to add any more delays making changes at this point.

[Joeshmeph]

Little late on this but i currently have this set up in a 2006 wrx. It made 280 on the dyno hitting 19 psi and spools close to 2700 rpm. I currently have stock headers and downpipe cause i cant find replacements, and cant buy gaskets at the dealership because the flanges arent the same as usdm. But other than that no gripes. I have an sti top mount, sti injectors, aps bov, and stock intake. Tuner said it could make more but would require e85 to get it.