F1 EFR 7670 Twinscroll External Wastegate Full-Race kit install
 

https://cimg6.ibsrv.net/gimg/www.s2k...dc970910ad.jpg

I made another thread addressing how many turbo'd s2k's end up for sale. I didn't want to end up being that guywith a 'pretentious build'. I want to keep it simple and enjoy my s2k until death do us part. I wanted to take on a build and be able to replace and diagnose parts myself in order to avoid the stealerships or jiffy lube mechanics at all costs. Being so committed and knowing what I want makes it easy to set up my parameters for this build:

For this build i wanted to use quality parts, delete unnecesary components to free up space and complexity to wrench around the car. I want to put things together in a way that will maximize engine efficiency/longevity/refinement/keep things easy to diagnose/pull apart and replace.

My turbo build parameters:
(1)Make max amount of power out of an AP2 shortblock for street use/highway pulls.
(2)Have a setup that will minimize turbo lag.
(3)Keep stock look/sound including oem wheels, mufflers, motor mounts.
(4)Rev to 10K rpm's (For the sound, uniqueness, and traction philosophy of laying down power up in the rpm's let's you run smaller tires and keep traction ala highhorsepower fwd civics style).

Devil is in the details, basically am shooting for 650whp with earliest spool/best transient response possible in an oem’ish looking AP2 that can rev to 10K RPM.

Parts(reasons) are below, again this is to guide and inform anyone that might want to learn in the future of a very detailed goal oriented build.
Turbo
BorgWarger 7670EFR turbo which features:

• T4 Flange(bigger flange will keep intake temps down/increase engine longevity/allow for more power but sacrificing a bit of turbo lag)
• Stainless steel turbine housing(thinner steel housing basically aids in keeping exhaust temps hot/increases turbo spool)
• Twinscroll turbine housing(Faster turbo spool)
• 1.05AR(bigger AR will keep intaket temps down/increase engine longevity/allow for more power but sacrificing a bit of turbo lag)
• Titanium aluminide turbine wheel(most lightweight turbing wheel i could find to help transient response/spool up time)
• Ceramic ball bearing center housing(faster turbo spool)
• EFR Anti-surge cover(faster transient turbo response)
• EFR compressor housing re-circulation valve(basically a BOV that ebables faster transient turbo response)

Turbo Manifold
Full-Race Twinscroll Dual External Wastegate Turbo Manifold:

• Forward Facing manifold(slower spool up/more top end flow)
• High quality manifold (will not crack even when wrapped with exhaust wrap)
• 3" downpipe with electric cutout/oem mufflers.
• Dual external wastegates(best control of turbo pressure/aids in relieving exhaust backpressure)
• Titanium wategate downpipes(saves weight/decreases resonance and simplifies the install/removal of turbo)
• Twinscroll manifold[separates exhaust cylinder pulses enabling fastest spool possible/more efficient turbo spool)

Improving Tubo Spool Mods
that will help engine spool turbo up faster directly or indirectly/handle more boost:

• E85Fuel(allow for more power/less turbo lag)
• Injector Dynamics 1300CC Injectors(Excellent idle/low and high throttle response)
• 8lb ACT Prolite Flywheel(will help engine rev up faster/the faster we can climb rpm's the faster we can get into boost)
• Fluidampr crank pulley(will help engine rev up faster/absorb vibration from crank)
• Vibrant 6"velocity stack routed to passenger side headlight for colder air 3.5"turbine intake pipe(will help spool/power)
• Full exhaust manifold/pipes/turbo heat wrap(will keep heat in exhaust/faster spool/cooler engine
• Electric boost controller(will keep wastegates shut right before desired boost for quickest spool possible right up to desired boost pressure)
• AEM infinity ECU(Volumetric Efficiency based ecu is very straightforward to use)
• SOS throttle body(Modified oem throttle body enabling better flow through TB/will help top end flow)
• CNC Ported 4Piston Cylinder head(will help turbo spool up faster/better top end flow)

Getting more focused on highway pulls these are more build items i plan on adding/running.

• Full Ferrea valvetrain with titanium retainers/(will be lightening valvetrain to increase RPM to 10K rpm)
• BC stage 2 turbo cams(to make power more up top/stay in power band/ to rev out gears longer)
• Taller 245/45/17 Pilot Sport 4S rear tires(effectively increase gearing by 4%, add vertical/straight line grip/keep ride as quiet as possible)

https://cimg1.ibsrv.net/gimg/www.s2k...3b2ba59f47.jpg
My old greddy kit i removed a few days ago

https://cimg4.ibsrv.net/gimg/www.s2k...11c3f076cd.jpg

Thinking of removing this vtec pressure switch to feed oil to turbo
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Plan to install this 6\" velocity stack and air filter. Isnt as much space as i thought to make it fit. Turbo has 3.5" intake. This was on my wishlist for my build so ill have to make it fit somehow. Good news is that its right where an intake needs to be on turbod s2k. Near passenger headlight away from exhaust

https://cimg7.ibsrv.net/gimg/www.s2k...25cbadbda3.jpg

Almost there

Its gonna spool what it spools at.... not much you can do LOL

BW EFR turbos should have the best spool. TTBOMK are the only turbos with titanium aluminide turbine blades. Garrett went with hi-temp MAR-M on the new G-series, but that isn't lightweight.

For some reason Full-Race doesn't list their kit with an internal wastegate divided T4, but I imagine they would build it. The 1.05 AR EWG T4 they list with their manifolds should scroll as fast as the .92 AR twin scroll on a IWG T4 manifold, although the spooling difference should be small. Give them a call. Note that they build an EFR IWG manifold for the Supra with a 2JZ-GTE, so it wasn't an IWG issue.

I don't think there is any reason to not use the IWG on the EFR and its built in recirculating BOV. It also comes with a 3-port boost controller mounted on the compressor housing. Common changes are to use the Turbosmart IWG wastegate controller, a direct fit, and either Turbosmart recirculating Kompact BOV (they have a model that screws as a direct replacement) or the Full-Race aluminum cover over the EFR BOV.

There is a guy running a compound turbo S2000 with two EFRs. Videos on YouTube and I believe a thread here.

Sound Performance has a Quick Spool Valve (not cheap) that fits between a twin scroll T4 turbine housing and a non-divided T4 manifold. It has a flapper that directs the flow to one scroll. 4 years ago BW displayed an EFR turbine housing that had a similar flapper built into the housing so it could use a divided T4 manifold, but it apparently never made production.

Then, of course, there is anti-lag. BW has a speed sensor for the EFR and an EGT sensor may also be helpful to avoid excessive turbine spool or temps.

Boost, fuel, and horsepower levels aren't specified. If the power level is under 500-550 and/or a oxygenated fuel is used, it may be possible to use the small frame EFR, such as the 7361, rather than a big frame EFR. The smaller turbo should spool faster.

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Not much done today but i was able to atleast get the filter more in line.

https://cimg7.ibsrv.net/gimg/www.s2k...5ce9f754d0.jpg

Plenty of space to install and get to the factory oil filter. Not going to miss using an oil filter relocation kit! Oil relocation kit just adds more complexity and possible leaks/take up vital space/are in a really hot environment. Plus not having to pump through an extra 2ft of hoses should make oil pump and oil pressures happier