EFR 7064 Twin Scroll / IWG / Pfab Top Mount / V-Mount build
 

After 3 or 4 years of tracking the car in NA form, I decided I wanted more power, especially after moving back to high altitude. A couple months ago, I started researching builds and what was available in making as much as I can a bolt-on setup for me and really didn't find anything that suited my needs. This caused me to message one of the local S2000 fabricators. After a good bit of messaging back and forth, I met up with him last month and dropped off my turbo with him to build me a custom manifold and downpipe. After a little bit of wait time due to being further down on the list of already committed projects, I started receiving pictures as the manifold progressed and fast-forward to yesterday, I went and picked i up. With my requirements of using all the built-in stuff on the EFR, as well as working with a turbo with physically large dimensions, he put in the work to figure it all out and build a beautiful piece.


That said, more on the car... It's been a typical NA track car (TTB, but probably could be TTC), but on E85 previously using STi injectors and a 155 lph pump in a surge tank (stock everything else). I already have some other needed items like an AEM EMS2, WBO2, etc. This is a winter project with no deadline since I have a lot of stuff on my plate due to recently moving and buying a house that needs things worked out (like the garage space being setup for my usage... And a heater!).
Things currently on the build list:

- EFR 7064, .92 Twin Scroll w/Turbo Smart 2-port actuator
- Twin Scroll, IWG turbo manifold + 3" downpipe
- ID1300's
- SoS Surge tank that I now need to swap a 320 lph pump into.
- Ordered and SoS V-mount
- bunch of misc shit that'll have me waiting on parts and frustrate me during the build. :)

I told my wife that this is what she got me for Christmas. :)
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As noted, I have some work to do in the new garage before I can even get started tearing the car apart.

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Being mocked up and welded.

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I also asked for the flange to have some additional bracing.

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And now I get to start playing with it all. This manifold is stout... Almost kills me to add this much weight to the car with the manifold and turbo, but should be fun!

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More parts porn...

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sexy ^.^

wow looks nice,BTW you have my favorite sti as well. The kit looks nice. have him fab you some heat shields for both manifold and turbo.
Thanks for sharing the thread with me.


And i followed your recommendation and ordered some ohlins dfv. Currently they say out of stock but i dont really care when i get them

I've been following your thread. I was considering trying to bottom mount my turbo as well, but we'll see how this does for me.

Thanks! It's my favorite generation of STi as well. :) It looks stock, but it's just as worked over as the S2000 with a built motor, EFR turbo, coilovers, etc. :)

Good to hear on the DFV's! I'm positive you'll love them. Where did you order from?

Yes i almost came close to buying that generation of wrx but passed on it for my mazdaspeed3 choosing raw power over beter driving dynamics with awd vs fwd. Back then i didnt know much about powertrains and how different they drive. I ordered them from rallysport direct for just 1840. They are out of stock but who cares. Im in no rush to get them as its still cold outside anyways. I dont see any issues with top mount. Only thing is heat is going to accumulate underneath the hood but that shouldnt hurt anything and isnt exclusive only to top mount.Has the v mount shipped out yet?

The Turbosmart one works MUCH better than the BW one, you'll like it. If it's still going to be a track car an oil cooler if it doesn't already have one would be a good idea.

Yeah, I use a 2-port on my STi with an EFR as the BW one did not do well. I had to run the vent port on the supplied EBCS to the bottom port of the IWG to get it to bring WGDC down.

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Here is a before and after on WGDC. First graph is with the second port vented, the second is with the second port going to the vented side of the EBCS. No tuning changes were done.

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It does already have an oil cooler, however, I am going to upgrade and have better placement since I'll be using a V-mount. I will likely get a Fluidyne Therm-HX cooler as I have had really good performance with them in the past.

The turbo you are using is both water and oiled cooled right?

Yes, to both turbos.

Will be interesting to see how this setup will compare with the one I have from Full Race with the same turbo. Btw your going to love the low end grunt this turbo gives you.

gonna be a long build. you think you will have it done by this coming spring? And also that rubber hose coming off the cold side of the turbo is so close to the hot manfold. you think heat wont affect it?

I've done bigger builds. It's not the build that will slow me, it's the other stuff I have on my plate. There is more room than what it seems on that hose, but heat shielding will be abundant. I have a Boost Resource turbo blanket for the hot side and I'll build my own Inconel heat shielding... In addition to anything else needing addressed.

Sorry, I missed this earlier...


I hate RSD. I'd cancel the order and order from Urge.

Heat will accumulate somewhere, however, I will be doing some hoot venting. I have not gotten notification that the V-mount is complete.

I have never had an issue with RSD and their price is significantly low enough to take the risk. BTW i would like to have some heat shield on my after market header too. Not that the s2k ever really gets hot in na form. Just for the factory look. I look forward to seeing it when its done. hopefully you will make it out to one of the fast fridays at MAM

Do yo have an aftermarket header yet? If not, I will have my SwainTech coated PLM for sale.

As far as RSD, I, and several others vent here: RallySportDirect (am I rude?) - Subaru Impreza WRX STI Forums: IWSTI.com

I'll make it to MAM.

yes my S came with a skunk 2 header already installed. But nice think about the car is even after running it hard you get off track and pop the hood and barely any heat coming off of it. In contrast my mazda gets so hot the hood actually burns you if you dont open it very quickly and put your hands on it too long. Will be awesome. Maybe we can do a day out there together. Its always nice to have another noisy 4 banger at the track. Im hopefull i will have tires and wheels on by then. Let me ask you this, how much camber do you run on your front end? Im thinking of taking my old 17*8.5 et+30 with 245/40/17 and fitting those to the front with some extra camber.

My progression of alignments can be found here: https://www.s2ki.com/forums/s2000-br...eview-1121439/

good review on them I will go with your alignment specs when im ready

Nice dude. The design of his runners on your manifold is different from how he normally makes them. Looks dope all spun like that, wonder if its truer to equal length. The extra bracing seems like a great idea too.
My build is taking a lot longer than expected too, mainly due to waiting on parts like you said. Currently waiting for vacuum fittings which just shipped today...damn xmas! Haha

I'm not really looking to spool this up like a Subaru and peak torque and drop. I will likely run pretty low boost and shape my power curve to get the most usable power on track.

What A/R did you have on your 7064?
Yeah, the bottom side looks trippy. Not sure on whether it's more or less EL.

I haven't put deadlines on car builds in 10 years or so now. I know I'll never meet it without creating some issue for myself.

Got a few more items in the mail today. Picked some longer ARP manifold studs to account for the thicker flange and Nord-Lock washers. Also got a turbo blanket, which has to go back in return for an IWG version. :) The shirt is just from a customer that I tune (my logo is the lower left).

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Nice! Any preference on turbo blankets? Im thinking of cutting out the hood for lower underhood temps.

if all goes well i should be able to fire her up tomorrow!:eek2:

I went with a Boost Resource blanket as they fit well and work extremely well. I have one for my EFR 6758 on my STi, however, laziness to not taking the intercooler off to install it has won the battle so far.

How much do those blankets go for?

is there an off the shelf solution for oil and water lines for the turbo or do you have to make your own?

I was just planning on making my own.

I had gotten my lines from full race. Really good pieces

Sounds like serious work

To make lines?

Yeah, im sure some specialty tools are needed

Depends on what I end up doing. I've always made my own lines for nearly everything, however, I am tempted to make a hard line for the oil feed. If I do that, I will need to pick up some tools. I like the idea of being about to route a hard line where I want it and not have to keep a braided line from rubbing or be attached somewhere.

hard lines always look sexy, thats the one thing i never learnt how to do back in my air ride days

Nice build! I was hoping you'd create a thread. There aren't too many well thought out FI track builds. Is there a reason you opted to go with such a big turbo? That's a divided t4 turbine housing right..? What's your power goals?

I didn't think this was really a big turbo at 56 lbs/min, but I think I can get it to spool within reasonable usage and hang on I top. Boost will likely settle around 10 PSI, likely in the 400ish whp range. It's also the smallest B2 frame they make and I don't any B1 frame will keep up with this motor on the exhaust side, on track. Yep, it's a divided T4 twin scroll and a paired manifold.

Its not really a big turbo, Its sort of a strange turbo though. It has a compressor of a gt30 and a turbine of a gt 35. This means it can spool quickly and produce large amounts of boost, however it runs out of flow quickly. On a f20 or f22 the flow will be inefficient at close to 8k rpm. The better turbo is the 7163 for the f series motors. I am running the 7064 on my f24 build and you can tell it lacks top end. If I did it again I would go with the 7163.

The 7163 would likely choke the exhaust at high RPM, especially at constant high RPM. Robert Thorne and I spent some time working out a good turbo for the application, so I'm pretty confident in it, especially since I'm not trying to make a typical Subaru curve. I intentionally went for a larger A/R and twin scroll for helping it stay efficient for a large portion of the powerband... which isn't going to be very high.

For street duty, I probably would have gone with the 7163.

Ya the "cold side" doesn't seem to be too big, I guess I was just a little surprised by such a large hot side with a divided t4 housing. Many people run a t3 hot side/t4 cold side configuration but you're running a straight t4. Like you said, it should certainly help flow in exchange for a slower spool. I'm far from a turbo expert, it'll be interesting to see how it runs. :thumbup:

I'm not familiar w/ BW turbos.. Is a B1 frame on the hot side a t3 flange, and the B2 is a t4 flange..?

The idea of the large hot side is to let it breath, while pairing the cylinders properly for a twin scroll to help with the spool.


The B1 vs B2 is in reference to their frame/cartridge, with the B1 being smaller.


This isn't my picture, but it's a exact comparison between my 7064 (B2) vs my 6758 (B1).

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Seeing as how most guys running turbos use external wastegates (that divert a good deal of exhaust flow away from the turbine housing), perhaps a divided t4 turbine housing really isn't that large. I guess it really just depends on the power curve you want. Heck, a Greddy turbo kit can hit ~350whp w/ a t25 flange, but the top end clearly gets choked and it's hard to make much beyond that. The gt30 upgrades w/ the t25 flange seem to flow a little better. When looking at the SOS kit with the divided t3 housing (looks like a poor choice), it clearly gets choked up top as well. With a large(r) hot side I'd imagine your car will pull hard to redline, in exchange for a slightly slower spool. I definitely like the internal wastegate and simplified "package." Did you say you're relocating the battery as well?

The EFR turbos have an excellent IWG. The vented exhaust never really makes it into the turbine housing, which is another reason why I chose this turbo to run IWG with. :) I don't suspect the boost threshold to be so high that spooling this turbo will be an issue. When I sized the EFR for my STi, I went with a larger hot side than most at .85, but it has reasonable spool and doesn't choke up top. It is also a T25 flange. Many of what you've stated is why I elected to build my own setup. There wasn't a single kit out there that met all the requirements I had. :)

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The battery will probably have to be relocated. I used a 4ish lbs battery, so it should be pretty easy to fit anywhere.

Gotcha, ya I've seen a lot of pictures of EFR turbos, but since they're so large not too many folks use them, unfortunately. I wish someone would make a kit for the S that uses an EFR turbo.. Regarding the hot side and flow, it's been some time, but I'd swear I remember seeing some full-race dynos with EFR turbos using a t3 hot side that didn't fall off up top..? I know yours will be a track car, but how does that change things? Are you simply trying to maximize flow so perhaps there aren't restrictions and more heat buildup as well? I'll be interested to see your V-mount setup. All things considered the v-mount setup seems like a bargain from SOS compared to their turbo kit. I like their hot side turbo kit and its simplicity, but the price and design of it ultimately make it not for me.

I've fancied the idea of hodge podging together my own turbo kit with a greddy style log manifold, upgraded gt30 turbo, and an SOS V-mount setup. :D In theory I think it would be ok, but my biggest concern would be the manifold being a restriction. My free time has been bogged down with kids lately and I don't even get enough track time.. Me personally, 320-350whp would be plenty. My car is still a street car so keeping AC/not relocating the battery/etc is nice. Definitely excited to see how this turns out. :thumbup:

More parts showed up, so I probably ought to get to work.

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Looking good man. bet that v mount is going to look amazing once its done. Ive been doing some work on mine. check out the build thread.

sick build bro, cant wait to see the finished product. (i have been lusting after that v mount setup as well, but im going to experiment with my setup for now before i bite the bullet).

l am already subscribed to your thread. ;) I'm already following it. It's coming along nicely and when you want to upgrade spring rates, I might have mine for sale to go even stiffer. I should see you out at MAM/RPM this year as I want to do a Fast Friday and a MACE Roll Race event.

Thanks. I'm pretty excited about it all. I'm trying to do it all right the first time... I've overlooked things in the past which were fine for a street car, but then killed a motor on the road course. That's been over a decade ago, but you never forget. :)

Yes we will definately meet at MAM,Dont know when the track will open. i hope to be ready to run by march, hopefully they are open when my spring break starts in march. Hopefully the weather clears up by then.I will consult you on alignment specs as i have to give them to the guy who does the alignment for me

I think they open up in May, but there should be a schedule posted on their website. As for alignment, I know a guy at the Honda Dealership that can get you squared away and maybe I can work out the same deal I had with him for alignments.

At which dealership? i usually go to the shop inc in lincoln. may is pretty late, thought the weather would clear up much sooner than that

Superior Honda.

Unless the weather clears up really, really early, they go seasonally which generally brings people later spring.

that would save me a long drive to Lincoln for sure. i will pm you when im ready for the alignment

Started tearing the car apart last night... I am deleting everything I don't need, so some crap is getting cut out for ease of removal. :)

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Looks like a very promising build!!! Looking forward to see how you make your V-Mount.
I am heavily leaning towards the Full-Race manifold to help keep the weight down low and avoid the need for a scavenging pump.

Which Rad will you be using?
Will you be runing a vented hood?
What made you chose that Manifold?
Was it a size constraint to be able to run a EFR turbo with IWG?

If you skim the thread, you'll probably find the answers to all your questions. ;)

- It's and SoS kit. It comes with its own 2-pass radiator and the V-mount setup can be seen on their site.
- Yes
- Nothing out there met the requirements I had so I had a custom manifold made.
- The [EFR] turbo itself is big, and even longer with an IWG. Turbo placement is a little different than a more typically used turbo.

What are your thoughts on the size of that Radiator from the SOS kit?

I would be tempted to create some shrouds on each side of the V to force all incoming air into either the IC or Rad...

What clutch are you runing?
Any mods to your Diff/rear end?

Great start, so what Aero are you going with on the car :D

Our V mount looks similar but its more in house. Using a bigger radiator has worked for us so far. Kept the factory fan as well. When do you plan on her being ready?

Hard to say without any testing, but it looks like it'll be able to keep up. I was already planning on making shrouds to keep the air from wasting around. I have not decided on a clutch yet and the differential is stock.

Still TBD on what I do for aero. No deadline set on this car as I've got too much else going on that I would bust any deadline I'd set.

I completely understand, Sometimes when you are forced to take extra time you end up doing things better then you even imagined.

Still making messes, but almost everything is out, to include the A/C. Also sending the manifold out to ATP to get the Inconel heat shield treatment. :)

I did test fit the SoS intercooler and it doesn't line up very well. A little disappointed with this. I'll have to notch the holes more than they already are from SoS.

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looking good. I forgot which hood whee you going to use with your setup? Are you going to make some shrouds for both the intercooler and rad?

Also i just noticed those look like Re71R tires, how do you like them?

I was planning on modifying my OEM hood. I have only had the tires on for maybe 200 miles and one autox. I was faster than every other S2000 until I slid it into a light pole. It was a fast course and I was deep into 3rd gear... Was a long slide.

oh man sorry to hear that. was alot of damage done? I might pick up a set of those tires too. they are currently the fastest 200tw tire you can buy. im just waiting a little bit till tire rack tests a set of the new hankook rs4 to see where those stack up because i have heard the re71 wear down very fast

I got lucky in the hit and I was maybe doing 5 mph when I hit. I was more scared of hitting people, because that almost happened. It didn't touch the frame or suspension, so the car is still good, but now it's strictly a track car.

For road course, I would probably go with a different tire. These come up to temp fast and are good for AutoX, but may not be the best for track. Honestly, I like a second set of wheels and some Maxxis RC-1's.

Why would you not recommend them? I don't want a second set of rims and tires. I'm actually going to sell the ones I have because I want to cut back on how much stuff I have to move with when I'm going back home to Ca

They'll wear fast and will probably get greasy, sooner.

Honestly, my personal opinion, if you're going to track its worth having a second set of wheels for that purpose. I understand getting rid of shit, but I might even get a 3rd set to have a good set of tires ready at any time.

yeah honestly if I get one season out of them I will likely throw them out at 50% tread anywAys. I've been reading lots of reviews on them and it seems they don't get greasy very quickly despite quick warm up but didn't last as long as the rs3. I really liked the rs3 aside for horribly slow warm up in damp conditions

I run mine to the cords!

I haven't had the pleasure of doing that yet due to ever changing seasons here. I hear most tires get faster right when the treat first wears down

RE71 are pretty damn good on a road course. They are actually as fast as a Maxxis RC1 from our experience. The RC1 will just last you multiple seasons and 50 heat cycles. Its insane how long the RC1's lasted on my car this year. That's with multiple rolling burnouts ol

I had 30+ heat cycles on my RC-1's and shredded the outside edges as I needed to go with more negative camber. I went to Hoosier's after that set and then won a set of Hoosier's, but I'll likely be back on RC-1's when I get back out on track this year. For the money and the wear/grip, I loved them.

Thats pretty good. only problem is running those would require a trailer for sure which i am definately not ready for yet. but to get that much life out of them is impressive. must be a high quality tire. How about the advan neovas? those things are so pricey and i dont get why!

I have a trailer, but with the RC-1's I've been known to drive to the track on them. You're close enough that you can do the same.

i've also driven to the track on RC1s.

Here its definately feasible as im close enough to the track, Problem is i wouldnt be able to take them back with me to california as all the tracks there are atleast an hour from my house

BTW i think i have seen you on speedacademy youtube channel