Ultimate Race Wagon build

5 years ago, almost to the day, I blew the motor on my wagon at the track. Which started the journey to build a streetable wagon that was an ideal track toy. I had 5 goals, 4 of which I accomplished. The 5th was the motor had to last 50k miles. It lasted 29k.

 

My wagon details are here: http://legacygt.com/forums/showthread.php/boxkitas-wagon-181893.html?t=181893

My experiences with that build & the upgrade to the Miata are here: http://legacygt.com/forums/showthread.php/boxkita-racing-track-days-206308.html

And the disastrous results of the HG rebuild here: http://legacygt.com/forums/showthread.php/boxkitas-random-thoughts-while-wagon-collects-dust-garage-233455.html

 

Recently I bought Sgt.Gator's Silver Eagle, which was ICY Racing/Phoenix Racing's SRRT wagon. You can read more it about here: http://legacygt.com/forums/showthread.php/cool-article-05-scca-wagons-floating-around-still-73859.html

 

So with that out of the way, here are my goals:

1. No blank checks - I want to build it in my garage

2. I want similar performance to the 2012 build - 335tq from 4k - 7k & 1.25G cornering

3. Car must be able to run 4 races without losing an engine

4. If possible, car must be a front-runner in its class. This is last for a reason. ST class (http://www.race-st.com/) has almost no limiting rules except ~10lbs/hp. If you can imagine a solution and can implement it, it's legal. If its too good, the rest of the class will make it illegal the following year.

Plan: less drama, more racing.

 

Random list of stuff to do until I can make an organized list to do:

1. Figure out why the engine blew

2. move the dry sump tank to back seat

3. get a closed deck block

4. sort out front aero

5. add rear aero

6. get a 3d scan of wagon for aero

7. learn to weld / get a welder

8. get over my fear of cutting sheet metal and re-work fenders

9. Paint or wrap or dip

10. Get a color scheme

11. Find a sponsor or 3

12. Make a budget - Miata was $1500/weekend all-in

13. Get scales so I can do suspension at home

14. Get an answer to STI rear suspension or LGT rear suspension

Analyze the existing setup. What worked. What didn't. For what did, is it the best solution. For what didn't, why and how to make it better.

 

1. 1st Engine blew

2. 2nd Engine blew

3 - deleted

4. Dry sump tank radiates too much heat

5. Wing is needed in back to plant the rear

6. Wheel bearings didn't wear out (an expensive and common problem 2012 version)

7. Ideal battery placement

8. Data logging system

9. ECU tuning

10. Tire usage

11. FMIC vs TMIC

12. Splitter mounting & location

13. Undertray

14. Suspension settings

15. Windshield fogging issue

16. data logging and idiot lights

17. Suspension components - the wagon suspension design is ~13 years old. Is there a better solution? Will the STI really work? Free Range Racing did a swap and was not happy with the results.

Engine build

 

The wagon will race in a group where the rules says if not specifically denied, it's legal. Looking to be highly "legal".

 

Have been looking at IAG stage 4 short blocks. AWDTuning (Mary Fields' company) uses them in their builds and its hard to argue with their results. I've sent an email off to the shop about a race motor (March 14, 2017). We'll see what we come up with.

93 octane is easy to come by. 100-108 is harder to get, but obtainable. Street wagon was tuned on 96, and tracked on 108 when I could get it and 93 when I couldn't.

 

Looking at an electric water pump - https://daviescraig.com.au/electric-water-pumps . As cavitation at speed was an issue the first time. Yes, running a bigger radiator would have helped. However, that seems like a poorly engineered solution. Not to mention its much harder to vent the bigger radiator. Have been looking at how to vent the radiator thru the hood to cut down on engine temps as well as improve aero.

 

Looking at a racing alternator. Smaller size with a targeted rpm more in line with the race motor's speed. On track, the street car was in 4-6k range most of the time. On the street, it was more of 2500-3500. Vast difference in average rpm range. Having an alternator matched to the average rpm range should gve better performance and lower parasitic drag on motor. Assuming race car will have same working range. One maker of custom alternators gives a how-to choose guide - http://www.powermastermotorsports.com/which_alternator_a.html

 

Looking at intake manifold. The fp or cosworth units look great, but $1100 !! Have been collecting intakes from various models (sti, specb, n/a, etc). The stock 05 plastic one with functional TGV worked fine on the street car. This may be chasing a "bling" item, or not. Needs more work to determine where the blockage in the air intake really is, if any. Found the Forsa Intake manifold (https://forums.nasioc.com/forums/showthread.php?t=2780740). The company is no longer in business, so would need a used setup. Contacting owner to see if they would share plans to make a one-off (and use Sgt.Gator's murray clamps)

 

Still dreaming about swapping in a DIT heads. Maybe willall can make a custom set? So many other fish to fry first.

Aero

 

ST rules say the rear wing has to be mounted behind the centerline of the rear wheels like this (audi tt rs fwd car):

http://photos.motoiq.com/MotoIQ/Features/VLN-TTRS/i-MczJcsD/0/L/_JEF9782-L.jpg

 

Radiator cooling: http://www.motoiq.com/MagazineArticles/ID/2985/PageID/5962/Nerds-Eye-View-Going-Endurance-Racing-With-Raeder-Motorsports-Audi-TT-RS-at-the-Nurburgring.aspx

Engine tuning

Turbo/IC/etc

Cutting weight

Wider tires vs cost vs suspension

 

Adding the fender brace discussion here:

the fender support system is crushable and pretty weak. I thought the front fender braces were bling. Now, I'm not so sure. Wondering what the rules say about reinforcing with metal that looks like tubes. The welds to hold on the OEM supports look ok, however, the metal thickness is not enough. There is room to box in the structure for more support.

 

Wider tires requires moving the strut mounting points inwards, as well as extending the body panels for flares. The front fenders are relatively easy to buff out (english wheel?). The rears are going to take more work. Still looking at the rear subframe from a STi to make this workable. Need to get the rear subframe off the 05 sedan first to measure everything.

What's working/what's not working/what's the plan to fix

Optimist's post: Rose City Opener May 2017 plan

 

it could happen - March 2017

Sub sub sub this will be my favourite new thread.

 

If you're okay with it, I'll update with suggestions here as they come to mind.

 

Turbo Selection

If you haven't already, learn to use the BorgWarner Matchbot. As an example, this is my initial cut at a plot for the EFR 7670 I'm planning on running next year: EFR7670 Correlating with existing dyno charts from GD STi's (Single AVCS) will give you a good idea of how close your results are - you'll probably want to go bigger than a 7670 if you want reliability at those torque numbers.

 

7. learn to weld / get a welder

TIG welding is great, if more difficult to learn than MIG. This is a very well-rated welder at a very well-rated price: AHP AlphaTIG. Patience is key.

 

8. get over my fear of cutting sheet metal and re-work fenders

Yes. Once they're partially mangled, it gets easier not to care.

 

11. FMIC vs TMIC

This is a decision every Subaru owner gets all flustered about at some point. It's a compromise, but for a dedicated track car I'd be leaning towards FMIC. Disadvantages of both are listed below, and advantages are the opposite of the disadvantages.

 

 

Disadvantages

FMIC:

Longer piping = more lag (not a big deal on track where immediate throttle response isn't as critical as AutoX or street use)

More risk of couplings popping off

Off-track excursions and debris are more likely to destroy the intercooler

May require removal of bumper beam (if this is a dedicated track car with no cage, then no biggie if rules allow it)

Moves COG/weight distribution forwards, increases cornering moment of inertia

Typically more expensive when factoring in piping, etc.

 

TMIC:

Limited Core Size

Engine heat heats up intercooler at low speeds (pits, staging, etc)

Limited airflow over intercooler (especially with the relatively small LGT hood scoop, making it difficult to cool down a heat soaked TMIC)

Engine bay is more cramped

Raises COG

 

TMIC Data collection, street use

http://forums.nasioc.com/forums/showthread.php?t=2660933

http://forums.nasioc.com/forums/showthread.php?t=2513808

 

 

 

I'm excited for your findings!

Sub sub sub this will be my favourite new thread.

 

If you're okay with it, I'll update with suggestions here as they come to mind.

 

Turbo Selection

If you haven't already, learn to use the BorgWarner Matchbot. As an example, this is my initial cut at a plot for the EFR 7670 I'm planning on running next year: EFR7670 Correlating with existing dyno charts from GD STi's (Single AVCS) will give you a good idea of how close your results are - you'll probably want to go bigger than a 7670 if you want reliability at those torque numbers.

 

7. learn to weld / get a welder

TIG welding is great, if more difficult to learn than MIG. This is a very well-rated welder at a very well-rated price: AHP AlphaTIG. Patience is key.

 

8. get over my fear of cutting sheet metal and re-work fenders

Yes. Once they're partially mangled, it gets easier not to care.

 

 

I'm excited for your findings!

That borg warner is endlessly fascinating.

 

Feel free to chip in. More the merrier

Sub'd might not add much but I'm sure I'll learn something.

 

Good luck with the build.

I am looking forward to you getting over your fear of hacking fenders. Plus, whatever you figure out for the rear bearings.

I don't know if I have another 5 yrs to wait, but I'll sub for now.

Oh, heck yeah, I'm in.

Sub for closure. I'm just past my 5 year mark myself.

Sub'd for probably being on the crew at race days if I'm not on a ship at the time. And also putting in different ideas as they come to mind.

Just found this thread. Personally I think you should have kept all this in the other thread.

I only blew 2 engines in the Silver Eagle. The first was the oem 2005 one raced by Phoenix (oil pressure loss in turns); the second is yet to be determined by you.

The third engine I blew was my Spec B at ORP.

The fourth engine was the new STI that had an incorrectly setup fuel pump that caused super lean conditions and melted the #4 piston.

 

#18. 6 Speed Tranny heat-cooling. It needs a better external pump cooler, or an additional cooler off the internal oil pump.

 

Here's a few thoughts that are IMHO:

Assuming you are building for ST primarily and SPM & ME0 for extra fun.

 

The front and rear aero are sorted enough for now. I don't understand the comment about needing a wing in the rear, you have a very nice one!

It would be nice to make the front splitter more of a quick on-off setup. The best way to do that is some combination of Dzus like fasteners, quick turns, and removing the front bumper/splitter as one combined unit. It can be done, it will just involve quite a bit of fabrication.

That also means you'll need room to store the front bumper/splitter in your trailer going to the event.

 

Yes you need to learn to weld. I've been a mig/stick welder since 15 years old. I have a TIG but I'm awful with it. I'm going to take TIG classes at the local community college, which will also give me access to some other cool tools.

 

The Blouch turbo is fine for the ST class, no need to replace that.

 

FMIC - TMIC is not an issue, that horse left the barn long ago.

 

Bigger Fenders. Now here's the conundrum! You need bigger wheels and tires. But upsizing them means the puny LGT hubs will be even more stressed. And without tubbing the front and rear wheel wells and all new suspension you'd be moving the wheels outward for even more stress.

 

Ideal battery placement: With that LI-Ion battery it's so light you can put it anywhere you want. I was going to move it behind the driver's seat on the floor just to shorten the power cables to remove weight.

 

Data Logging: The AIM Pista works great. Get Making Sense of Squiggly Lines so you know what it's telling you.

Just found this thread. Personally I think you should have kept all this in the other thread.

I only blew 2 engines in the Silver Eagle. The first was the oem 2005 one raced by Phoenix (oil pressure loss in turns); the second is yet to be determined by you.

The third engine I blew was my Spec B at ORP.

The fourth engine was the new STI that had an incorrectly setup fuel pump that caused super lean conditions and melted the #4 piston.

 

#18. 6 Speed Tranny heat-cooling. It needs a better external pump cooler, or an additional cooler off the internal oil pump.

 

Here's a few thoughts that are IMHO:

Assuming you are building for ST primarily and SPM & ME0 for extra fun.

 

The front and rear aero are sorted enough for now. I don't understand the comment about needing a wing in the rear, you have a very nice one!

It would be nice to make the front splitter more of a quick on-off setup. The best way to do that is some combination of Dzus like fasteners, quick turns, and removing the front bumper/splitter as one combined unit. It can be done, it will just involve quite a bit of fabrication.

That also means you'll need room to store the front bumper/splitter in your trailer going to the event.

 

Yes you need to learn to weld. I've been a mig/stick welder since 15 years old. I have a TIG but I'm awful with it. I'm going to take TIG classes at the local community college, which will also give me access to some other cool tools.

 

The Blouch turbo is fine for the ST class, no need to replace that.

 

FMIC - TMIC is not an issue, that horse left the barn long ago.

 

Bigger Fenders. Now here's the conundrum! You need bigger wheels and tires. But upsizing them means the puny LGT hubs will be even more stressed. And without tubbing the front and rear wheel wells and all new suspension you'd be moving the wheels outward for even more stress.

 

Ideal battery placement: With that LI-Ion battery it's so light you can put it anywhere you want. I was going to move it behind the driver's seat on the floor just to shorten the power cables to remove weight.

 

Data Logging: The AIM Pista works great. Get Making Sense of Squiggly Lines so you know what it's telling you.

I figured id bang away on this on this one until it was running then move back to the other one.

 

Tmic vs fmic - i never bot into it as my tmic never had issues. Sounds like oem vs closed deck.

 

I must have confused engine failures. Thot it was more. Oh well.

 

I had planned to swap 08 sti suspension into wagon which solved hub bearing problem. However need to solve "no engine" problem first.

 

Working my way through data power by buddy fey at the moment.

 

Welding. need to buy one. Kind of thinking its like buying coilovers the first time. Buy anything. use until frustrated. Then buy something better now that you know the right questions to ask.

Welding is all about practice once you fully understand the concept and how to prperly set up your welder.

 

Mig can be learned easily IMO but TIG is a whole other ball game.

 

I second your thoughts on first welder purchase. Anything that utilizes shielding gas will be great for practice.

If you can figure out how to put STI hubs in a LGT you will have solved the single biggest issue stopping LGTs from being great road racing cars.

 

The second issue is the R160 rear diff, but we know how to solve that with a 6 speed swap.

 

I left off the Spec B because by the time you add a front LSD and a trans cooling solution it's more cost effective to get a LGT and do a STI 6 speed swap using the internal pump for a cooler pump.

 

Now that I've run both the LGT Wagon and the STI I will offer this opinion:

 

The LGT Sedan is the best road racer in the Subaru lineup if you can swap in STI hubs.

 

The LGT sedan has the best natural aero, it has more room in the engine compartment for mods, it's easy to put up a firewall across the back seat to wall off a fuel cell and dry sump.

 

Ultimately the BRZ will be the best road racer once someone figures out how to dry sump it. So far no one has. It has super natural aero and weight distribution.

 

If I ever crunch the STI into a ball of twisted metal I may buy a LGT, strip it down completely, seam weld it, and build it up as a great all weather road race car. No matter what you do the car will always be at a disadvantage because the weight is in the wrong end, but when it rains it would be a winner in whatever class you build it to run in.

 

Or find a Murtaya to re-build. I've been looking and have contacted the main guy in the US. There's only 2 in the US, and one is in Seattle. I've invited him to Pacific or The Ridge next time we are racing so we can get a close look at his car.

I was wondering if oil starvation was a factor. Also wondering what can be done about it. I've got KillerB's oil pan and tray, and will only be running summer tires, not slicks, so I'm hoping it won't be an issue for me... but it still makes me nervous.

 

Regarding FMIC vs TMIC, I suggest FMIC because then you can seal off the hood scoop. That should mean lower pressure in the engine compartment, thus more airflow through the radiator & FMIC, thus better cooling for everything. Should also mean a little more net downforce, though that might just be wishful thinking.

 

My car was starting to overheat at The Ridge, partway into a 20 minute session. I had to ease off to keep it from getting out of control, which was a little frustrating. Looking forward to trying again with the hood scoop blocked off. And hopefully sub-90F temperatures.

 

I was at 375whp, and you'll be at 330-350, so that will help a little... but only a little. Is the 10#/hp thing based on the weight of the car, or the weight of the car and driver?

 

Not that there's anything wrong with your current turbo, but.... If you're looking for a turbo kit... I'm intrigued by KillerB's "Spoolinator" kits. Garrett turbo, Tial exhaust housing, v-band flanges, stock location. Not sure if one has been installed on a Legacy yet, but I can at least vouch for their header and stock-flange up-pipe.

What are your plans for engine management and tuning?

 

If you stick with open source tools, there's a couple of tables that help a LOT with a rich dip that happens about a half-second after mashing the throttle. I found them and I'm kind of proud of that. I don't know if Cobb has added them or not. I stopped paying attention ~4 years ago when life got in the way.

 

If you want to DIY, I'm happy to teach you what I know, and lend a book. It is not as complex as it seems, it just takes a lot of time to tweak and log and ponder logs. And a lot of iterations of that tweak/log/ponder cycle.

 

And you might need a safe place to do 3rd-gear pulls up to the rev limit. I used to have the perfect spot, but then the roads got rearranged... going to try to tune my new motor using 3rd-gear pulls to 60-70 and 2nd-gear pulls for the high RPM range. Hoping to do it all without breaking 70. Not sure if possible though.