Turblown Engineering Cast V2 IWG EFR Turbo Manifold
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Turblown Engineering's Cast EFR IWG Turbo Manifold now supersedes our older welded version . This manifold when combined with an EFR 7670, 8374, 9174 or 9180 delivers the fastest boost response possible for each frame turbo. This combination will make your 13B 2 rotor feel like a 20B in the low end and mid range at higher boost pressures.
Cast 347SS
This manifold is cast from 347SS which is far superior to 304SS. Not only does 347SS last longer at elevated temperatures , there are no welds like those found in traditional turbo manifolds. When a welded turbo manifolds fails, they almost always break at or next to the welds. A broken turbo manifold even if it features a life-time warranty can be a serious hassle to remove and send back in for repair, especially if you miss a race because of it. We have weighed our cast manifolds vs our welded units and they actually weigh a few ounces less! Since these manifolds are investment cast, they are less than 1/2 the thickness of your traditional cast iron turbo manifolds, and therefore do not retain as much heat as cast iron manifolds. There are zero downsides to this casting process vs welding.
Tapered Main Runner Inside Diameter
This manifold's inside diameter slowly tapers down as it reaches the T4 flange. This process is only possible with a cast manifold. A traditional welded manifold does not change inside diameter. This tapering process is identical to the volute of a turbine housing. By tapering down it increasing velocity, and speeds up the exhaust flow and increases boost response.
CNC machined flanges
All flanges are CNC machined to be perfectly flat. Most turbo manifolds are just belt sanded flat, which is not as accurate as CNC machining.
Smoother transitions
Welded turbo manifolds require hours of hand porting with a die grinder, and sanding drums to contour the change in shape from a round tube to a square T4 flange. We have taken this step, just like the rest of the manifold, to an even higher level of quality. The investment casting
Fitment
Only the 7670 IWG turbo will fit the FC3S 13BT engine without modifications. 8374, 9174 and 9180 require 1/8" removal of the LIM flange where it meets the block on FC 13BT engines. We do offer this service. S5 FC3S Waterpump housing will not clear 8374 or 9180 without modifications. One can swap s4 water pump housing( will swap onto S5 front cover will a little work).
7670, 8374 and 9180 will fit the 13BRE, or REW engines regardless of 2nd or 3rd gen chassis selection without modifications to the stock LIM. This system is RHD compatible for FD3S and FC3S chassis. 1st gen FB chassis fitment for engine swaps is same as above. Optional Inconel turbine housing advised for FC3S fitment.
TurboSource Inconel T4 turbo gasket is recommended. Standard stamped 304SS gaskets will require grinding on OEM 93-2002 Rx-7 lower intake manifold to clear 8374 and 9180 compressor cover. Slightly grinding is required to fit Xcessive Manufacturing 3rd gen lower intake manifold even with the Inconel Gasket sometimes. OEM FD3S airpump will clear EFR 7670 selection with no modifications. EFR 8374 & 9180 require slight grinding, and a custom tensioner bracket( see photos).
Pictured waste-gate bracket adapter is required for all chassis models. OE BorgWarner unit will not work with turbo orientation.
Studs are required for all IWG EFR turbochargers. Bolts physically cannot clear rear near turbine housing.
Optional 3" mandrel bent downpipes are available for FD3S chassis. Will clear RHD models. Stock location 3" 2 bolt vibrant flanges. Requires 3/8" hardware to bolt to OEM cat( not the same exact flange, but it does work).
5 year warranty on turbo manifold.
This manifold comes standard with twin 1/8 NPT exhaust gas temperature or exhaust manifold backpressure ports( plugs included- require anti-seize and final tightening if plugs are to be used).
Turbo Hardware is NOT included. T4 flange thread pitch is M10 x 1.5
- Brand
- Turblown
- Platform
- Mazda RX-7
- Engine
- 13B-REW
- Category
- Manifolds
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Alex M.
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★★★★★
They actually took the time to help me choose the right setup for my GT-R. That alone won me over.
Brian S.
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★★★★★
Everything arrived well packed and exactly as described. You can tell car people run this shop.
Chris D.
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★★★★★
I've ordered three times now and it's been consistent every time—accurate, quick, and hassle-free.
Daniel R.
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★★★★★
Customer support answered my fitment questions in detail instead of just sending a link. That meant a lot.
Jason L.
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★★★★★
Parts for my Supra showed up on time and bolted right up. No guessing, no drama.
Kevin P.
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★★★★★
Site is easy to navigate and checkout was simple. Whole experience felt dialed in.
Nate H.
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★★★★★
Communication was excellent from order confirmation to delivery updates. I always knew what was happening.
Ryan F.
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★★★★★
These guys are clearly enthusiasts. The brands they stock and how they talk about them says everything.
Tyler N.
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★★★★★
I've dealt with plenty of parts shops—this is one of the few I trust with big-ticket items.
Zach W.
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★★★★★
My 240SX build depends on good vendors. J-Spec Garage has delivered every time so far.
Cody J.
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★★★★★
You can tell they care about the scene, not just sales. That's why I keep going back.
Dylan P.
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★★★★★
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Josh H.
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★★★★★
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Kyle M.
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★★★★★
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★★★★★
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★★★★★
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Aaron F.
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★★★★★
Finding legit rotary parts is tough, but J-Spec Garage came through with RaceOnly gear that actually delivers.
Blake S.
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★★★★★
Finally found a shop that understands rotary builds. The RaceOnly pieces I ordered have held up great under real abuse.
Jake P.
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★★★★★
Everything for my FD—from RaceOnly parts to small accessories—showed up clean, labeled, and ready to bolt on.
Mason K.
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Noah V.
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★★★★★
The RaceOnly pieces for my RX-7 build fit exactly like they should. No grinding, no modifying, just bolt-on and go.
Owen T.
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★★★★★
It's hard to find a shop that really understands rotary builds, but J-Spec Garage clearly does.
Caleb M.
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★★★★★
Real rotary parts, solid communication, and no nonsense. Exactly what I want from a parts shop.
Isaac R.
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★★★★★
The Supra parts I ordered were clearly not cheap eBay stuff—quality brands and everything matched the listing perfectly.
Adrian C.
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★★★★★
I've been slowly building my MK4 and every order from J-Spec has shown up on time and ready to install.
Carlos N.
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★★★★★
They actually understood what I was trying to do with my Supra build and suggested parts that made sense, not just the priciest options.
Derek W.
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★★★★★
The turbo-related parts for my Supra came exactly as described and have held up great under boost. Zero complaints.
Javier S.
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★★★★★
I appreciate that they stock real-deal brands for Supra builds instead of filling the catalog with questionable stuff.
Miguel R.
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★★★★★
I'm picky about what goes on my MK4. J-Spec Garage earned my trust with accurate listings and solid communication.
Steven D.
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★★★★★
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Marcus D.
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★★★★★
It's refreshing to buy Supra parts from a shop that actually knows the platform.
Preston G.
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★★★★★
The turbo and supporting parts I got for my Supra were exactly what I needed. Everything matched the listing.
Trevor M.
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★★★★★
If you're building an RX-7 or Supra, this is a shop you want to know. RaceOnly parts for the rotary and quality Supra gear in one place is a win.
Victor H.
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★★★★★
It didn't feel like I was buying from a generic online store. It felt like a shop built for enthusiasts.
Wyatt N.
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★★★★★
Good communication, real brands, and parts that showed up when they said they would. Hard to beat that.
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