JDM EJ20R Twin Turbo tuning

[Dead91silvia]

Being that we have so few twin turbo Subaru's in North America, not many know how to improve performance.

I have a number of things I want to do and want to make sure what to expect when they are done, or if I should even do them.

1. BOV... I was told that adding one to a TT motor will produce run-ability issues. Is this true? The ricer in my wants to hear a BOV. Not super loud, but something people can here.

2. Boost controllers... Not sure what to even look at when looking at them. We have TT 300ZX's, Supra's, and a number of other cars. I just want to know what works best for the Subaru and what I'm looking at for cost.

3. Exhaust... I want it to flow more, yet dont want to wake the neighborhood. I can have a mid-pipe build, I just need to know optimum size and what not. I passed smog so I'm good for 2 years till I need to do it again. Also I will have the pipes built to bolt into the factory location.

4. ECU... I have seen a number of them on Ebay... Are they worth my time and money? I have seen a Prova, Apex, and Mines...

5. Turbos... I dont know what I have and if I was to upgrade, what do I upgrade to?

If there is anything I'm missing that this car would benefit from for upgrades, let me know.

So far I'm having fun with it! It's not overly super fast, but she gets up and goes pretty quick! I would just like it to be a little bit faster. I have hit the speed limiter a couple times without even realizing I was going that fast. :grin: I do have an extra EJ20R motor in my shp I might try swapping into a LHD car at some point also. :smt023

[Bip]

Being that we have so few twin turbo Subaru's in North America, not many know how to improve performance.

I have a number of things I want to do and want to make sure what to expect when they are done, or if I should even do them.

1. BOV... I was told that adding one to a TT motor will produce run-ability issues. Is this true? The ricer in my wants to hear a BOV. Not super loud, but something people can here.

2. Boost controllers... Not sure what to even look at when looking at them. We have TT 300ZX's, Supra's, and a number of other cars. I just want to know what works best for the Subaru and what I'm looking at for cost.

3. Exhaust... I want it to flow more, yet dont want to wake the neighborhood. I can have a mid-pipe build, I just need to know optimum size and what not. I passed smog so I'm good for 2 years till I need to do it again. Also I will have the pipes built to bolt into the factory location.

4. ECU... I have seen a number of them on Ebay... Are they worth my time and money? I have seen a Prova, Apex, and Mines...

5. Turbos... I dont know what I have and if I was to upgrade, what do I upgrade to?

If there is anything I'm missing that this car would benefit from for upgrades, let me know.

So far I'm having fun with it! It's not overly super fast, but she gets up and goes pretty quick! I would just like it to be a little bit faster. I have hit the speed limiter a couple times without even realizing I was going that fast. :grin: I do have an extra EJ20R motor in my shp I might try swapping into a LHD car at some point also. :smt023

I would advise you stay away from a BOV, I have used one in the past and it did sound good, but it reduces power and drivability. Some BOV's can cause a CEL aswell.

I don't have any experience with Boost controllers but I have been told they aren't worth the effort, it's better to just get a remap.

I have recently completely de-catted my exhaust and it sounds amazing! I would recommend it to anyone. However, to make the most of the extra flow I would advise you get a remap. If noise is a problem, you could always get an exhaust bung. Then when you do want it to be loud you only have to remove the bung. :wink:

I currently have a Prova ECU in mine and it has served me well. It has easily adapted to many of the mods I have done. However I am soon upgrading to a 4G ECU with an ESL board which means I can map it to make the most of the mods I have done.

The best turbo's you can go for with a standard setup is VF25(or VF26) with a VF27. This is what I am currently running.

Have you thought about moving your boost solenoid valve from the standard mounting point in the wing closer to the primary turbo? This shortens the length of vac hose you need and makes for a snappier response time when spooling up. It can also slightly increase primary boost. I've mounted mine just under the fuel filter on the suspension turret.

If you are thinking of getting your's mapped then I suggest you upgrade the boost solenoid to a 3 port. This makes mapping it easier and more controllable. You will also need an uprated fuel pump.

[Dead91silvia]

Thanks for the input! I'm sad about the BOV, but I do have one on my Pulsar so I guess that will work. When ever I get that thing finished... haha

On the turbo's... Is the smaller for the primary? I would assume so just because thats the one I seem to be using all the time till I get on the freeway and haul ass... haha

I'll talk to my buddy about making a mid-pipe. I know he can, but with laws here, you cant take cats out. If I say I'm using it for "track only" he can do it.

I'll see about the other stuff as well. I've been out of the turbo world for a while, so I forgot a lot of what I did know.

[Bip]

Yes you are right in thinking the smaller turbo is the primary. :)

[Dead91silvia]

What can I do about intercooler upgrades? I was looking at Red85celica's STi instercooler and it looks like I might be able to use that. Am I right and what would I need to do to make it work/fit?

[hansvonaxion]

The intercooler is actually very good for a top mount.

Pretty much what Bip said, except the ECU is not really tuneable, there is someone in the UK who can do it but it's pricey. And if you're going to start swapping the turbos as well you're probably better off going single.

I'd just do the exhaust first.

[Dead91silvia]

The intercooler is actually very good for a top mount.

Pretty much what Bip said, except the ECU is not really tuneable, there is someone in the UK who can do it but it's pricey. And if you're going to start swapping the turbos as well you're probably better off going single.

I'd just do the exhaust first.

Really?! It's just seems so small. Well, I guess the side mount I had on my Silvia was even smaller...

I'm not going to mess with the ECU for a while.

I have a friend that is going to buid one fo me when I get the time and money to spend. I'll have him build me a catless pipe and if it's too loud, I'll just put the stock one back in. :grin:

[Cervantes]

BOV - made my car run like butt
Boost controller - not necessary, but I have one and have benefited from it. I have Thea Blitz with 4 settings and it works awesome.
Exhaust -aftermarket downpipes and catless are the way to go IMO
ECU - you can replace your ECU with something like Mines or Prova. I have a piggyback and it works great. If you're going to remap, you'll have to start looking into replacing your stock fuel pump.
Turbos - I have only seen aftermarket turbos one time. It was on yahoo auctions and they were bidding on them like crazy. The VF25/VF27 seems to be the preferred combo for he twin turbo Legacy.

[hansvonaxion]

Really?! It's just seems so small. Well, I guess the side mount I had on my Silvia was even smaller...

I'm not going to mess with the ECU for a while.

I have a friend that is going to buid one fo me when I get the time and money to spend. I'll have him build me a catless pipe and if it's too loud, I'll just put the stock one back in. :grin:

http://www.autospeed.com/cms/article.html?&A=1931
http://www.autospeed.com/cms/A_1619/article.html

The cat doesn't really affect the sound too much, it's pretty much controlled by the rear muffler.

[Dead91silvia]

Really?! It's just seems so small. Well, I guess the side mount I had on my Silvia was even smaller...

I'm not going to mess with the ECU for a while.

I have a friend that is going to buid one fo me when I get the time and money to spend. I'll have him build me a catless pipe and if it's too loud, I'll just put the stock one back in. :grin:

http://www.autospeed.com/cms/article.html?&A=1931
http://www.autospeed.com/cms/A_1619/article.html

The cat doesn't really affect the sound too much, it's pretty much controlled by the rear muffler.

Read the article on the intercoolers... Damn! Thats just funny! So it's pretty much one of the best for stock. Thats funny!

[Dead91silvia]

BOV - made my car run like butt
Boost controller - not necessary, but I have one and have benefited from it. I have Thea Blitz with 4 settings and it works awesome.
Exhaust -aftermarket downpipes and catless are the way to go IMO
ECU - you can replace your ECU with something like Mines or Prova. I have a piggyback and it works great. If you're going to remap, you'll have to start looking into replacing your stock fuel pump.
Turbos - I have only seen aftermarket turbos one time. It was on yahoo auctions and they were bidding on them like crazy. The VF25/VF27 seems to be the preferred combo for he twin turbo Legacy.

Is there a specific model of boost controller? I have never really looked at them before.
Exhaust I think will be the first thing I do...
ECU will be WAY down the list at this point now. Just cant afford it.
Fuel pump is easy... Thats $80 down the street...
I found a set of VF27's for about $500 shipped. Not sure what the going rate is for them. Is that a good price? I just looked at my extra turbo's I have and it looks like the stock ones are VF20/VF21's? So that seems like a big upgrade to me!

[west_minist]

What year is the TT?

Is it carrying a Denso ECU?

[Dead91silvia]

It's a 96... I'm getting ready to drop in a 97 EJ20R.

Also.... Since I have the motor out, is there anything that would make sense doing to the motor? I though maybe a new larger turbo crossover pipe that goes across the front of the motor. Should I bother?

I'm also looking into getting an extra set of turbo flanges and having my buddy that works at an exhaust shop to build me a full 3" exhaust. He already did a mid-pipe that was a bolt in. Looking at the factry flanges and seeing how small the factory echaust is makes me feel that it could benefit from it. Just not sure if it will mess with the tuning on the twins.

[Cervantes]

I use the Blitz Dual SBC, it's made for high boost and twin turbos

[Snow Wolf]

Hi there, I know this is rather late to add to but hopefully it'll help someone along the way. I have a 1999 RSK B4 twin turbo. I have an aftermarket BOV (HKS SSQV) and it has caused me no issues whatsoever. No loss in drivability at all. Have aftermarket muffler and resonator but other than that factory exhaust. Was told by a member on here not to waste time on full exhaust system. Hope this helps