Legacybt 6mt Compromised Autocross Build

[legacybt]

Thanks both!  I'm excited to have this thing under the knife after a few years of accumulating parts. 

This spring a friend and I modified a new-to-me 3" exhaust with twin A'Pexi WS2 mufflers to fit the car.  It's much quieter than the K2 Gear Spec Neo that was installed on there (already a fairly tame exhaust for Subaru standards), and should be ever so slightly less restrictive to boot.  

The muffler hangers were made from scrap tubing lying around but no bender - they'll be redone if they ever fail on me.  Holding up well so far! 

 

The other project that'll be fitted this fall is a conversion to STI front to run the stronger bearings and GR STI Ohlins coilovers.  I had the hubs redrilled to 5x100 and ground the studs to fit the bearing housing.  Mated up with GD WRX or STI axles these should fit - I believe LIC motorsport used to make sets like this.  

 

[Febreze Mee]

Is it cheap enough that you'd be happy spending money on drilling another set should these ever fry? Or would you just replace the bearing itself?

And are you competing with the car? Or just enjoying motorsports recreationally?

Edited July 25, 2023 by Febreze Mee

[legacybt]

12 hours ago, Febreze Mee said:

Is it cheap enough that you'd be happy spending money on drilling another set should these ever fry? Or would you just replace the bearing itself?

And are you competing with the car? Or just enjoying motorsports recreationally?

Yeah, it’s cheap enough as long as I’m removing and reinstalling the studs.  Cash job for a local machinist, so it’s pretty reasonable!

I’m enjoying it recreationally; it’s my daily so I don’t have plans for it to be built up as a full track car.  I unfortunately don’t have the space for a second car, and there aren’t many cars out there that tick all the boxes like this one does - space, speed and fun.  Ideally I’d like to be able to get out to the track 2-3x a year.  

Re. the GR Ohlins coils - I also had rear top hats waterjet and I drilled them out to fit the Ohlins bolt pattern.  

 

[Febreze Mee]

I appreciate the time and energy going into this next chapter of parts. 

[legacybt]

A couple more photos of the front knuckles and hubs for a size comparison.  I’m not excited about the increase in unsprung weight, but I am excited about the increase in strength.   Combined with two piece rotors I’m hoping these stand up to some longer term track abuse.  

Note the difference in spline length between the LGT and STI front axles, the axle nut won’t be fully threaded on.  GD front axles are the same overall and have the right spline length, so I’ll be using those instead.  

Next up: engine stuff.  

[legacybt]

Engine build update time.  I've been reassembling a new-to-me long block.

- STI block and nitrided crank

- Cosworth rods & pistons

- Cosworth KK3766 CNC ported big valve heads & cams

- Grimmspeed head gaskets

The engine had terrible leakdown numbers when I got it, fortunately only due to carbon buildup on the valves stopping them from seating properly.  I partly tore the engine down, checked ring gaps, inspected bores and had the heads cleaned and serviced.  
 

Before: 

 

After: 

 

 

 

More to come!  

 

Edited August 19, 2023 by legacybt

[legacybt]

Another update.  

Engine fit-up is getting closer.  There's been a good bit of custom plumbing, sourcing fittings and electrical harnesses exhaust and turbo outlet elbow welding (thanks to a friend) with plenty more to do.  I wanted to stay TMIC (we'll see how long that decision lasts) and worked to find the shortest turbo-intercooler routing possible.  Very happy with the result, hoping my measurements for space between the turbo and wheel arch are accurate

Setting valve lash was also a super slow process doing it the first time. 

 

Exhaust cams: 20004727 Cosworth EXH EJ20 WRX 268/10.2

- I can't find any info on the specs aside from some old forum posts.  

Intake Cam: Cosworth 20004723 Cosworth EJ25 STI 277/11

- I'm a bit concerned about them not being nicely matched, but oh well.  I'm going to run them as-is.  

 

Turbo: GTX3071R Twin Scroll with dual Tial MVR Wastegates plumbed back into the exhaust

Grimmspeed TMIC

Mooresport fuel rails and Goodridge Aramid lines (not pictured)

ID1300CC injectors

 

Turbo/EWG setup:

 

Engine:

 

Fitting up turbo outlet elbow:

 

Turbo welded:

 

DIY Cylinder 4 Coolant Mod:

There is a ~10mm restrictor in the hose that also prevents it from kinking

 

To do before engine install: 

Get the header heat shields to clear the Killer B oil pan (taken way too long)

Weld up fuel distribution block bracket

Plumb BPV back into intake (better boost recovery, nice-to-have because speed density)

Route coolant hoses to EWGs

Route vacuum lines

Install engine accessories and timing belt

Fit turbo oil feed

Re-do turbo coolant lines in AN

Install wiring harness on engine

Properly install cam covers

Wire up speed density harness (ordered all connectors etc)

Install sandwich plate for oil cooler

Wrap or build heat shields for up pipes

 

 

Things are starting to feel real! It's a slow process.  

Edited September 7, 2023 by legacybt

[Enlight]

Those pictures are giving me flashbacks

[Febreze Mee]

That turbo setup is going to be so, so sweet! I can hear it already.