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Homebuilt GC8 for Time Attack
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Old 03-03-2015, 04:28 PM   #1
Join Date: Oct 2011
Location: Cyprus
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Posts: 164
Default Homebuilt GC8 for Time Attack

Always wanted to start a build thread but never had enough time or interesting things to write about. Now looking back I thought that I have something to share, some ideas for this season in local racing series, and it will be good to start a journal just for my own record and as a motivation to move forward.

Short background story.

It all started in 2013, by that time I already owned Impreza STi type-R for couple of years and found myself a bit confused with it. Here I need to mention that I live in Cyprus. It's rather small island in Mediterranean Sea Cars are RHD here and before country joined EU lots of JDM cars were imported. So, sometimes you can spot quite rare japaneese cars here. When I saw my Type-R I was amazed because in Europe you rarely could see 2-door Impreza. At that point I wasn't even aware of existence of these models, I thought that type-R sticker is just a bad joke of some honda fan. Also, I wasn't big subaru fan at that time. Imprezas were just much cheaper than similar vintage EVOs.
So, after owning this car for some time I was confused. It was old (1997), poor market value, not very reliable but eating money really fast. Insurance was expensive, fuel costs were crazy... Then I ran into head gasket problem while trying to sort out mess with vac routing. I had engine rebuilt only to get a dropped valve 6 month later (the next week after I got car mapped after prolonged break-in period). So, I just put in used engine from salvage yard and thought "what to do next?"
I wanted to mod the car but I kept questioning myself, why do I need to do that? Well, at that point I ran onto local time attack series and it was perfect. Owning this car become full of sense in one moment and participation in "Street" class with strict regulations promised to save me from expensive mods. Basically I had to keep engine stock and no lightweight parts were allowed, so I could only get suspension. I was happy with this because I wasn't excited in modifying good and quite a rare car extensively. I even bought DZ03G tyres in size that fits without any modifications like arches rolling.
On local track where all time attack events are held I got lap times around 1:18 after I changed some shitty lowering springs for stock sti ones and I managed to get nto 1:15.xx on the first event I took part with coilovers and group N bush kit installed. It was mid-season 2013 and I even managed to win that event in my class although I knew that there's one EVO 6 lapping the track in low 1:14.xx, he just wasn't taking part in that event.

Then my Dunlops arrived. That was the day when I realized that tires are probably the most important single thing that will define your lap time. This time fast EVO came to the event and did low 1:14.xx lap again. I managed get to 1:13.xx. (he had same tires btw ) It was a shock, for me in the first place. The next event was on the next day and some guys came to check the car asking if turbo was stock and so on, because such time for street class car was rather surprising

Long story short, this car took me to second place overall in 2013, and win in 2014 in AWD (Unmodified) Street class. The car won every race it participated in. In 2014 I managed to set fastest unmodified street awd class time ever and if I recall it right - second fastest time among all street cars time loosing more than 0.5 sec to GDB from senior "Street Modied" class (engine mods allowed + removing aircon and stuff) and winning just 0.03 sec from Corvette ZR-1 in third place.

This is how it looks like

And this is one of the most fun videos - free ptactice session before final 2014 event, in wet

2014 Time Attack 5 Practice:

At the end of 2014 season I decided that keeping a track dedicated car in good looking condition capable for driving around city is hard, expensive and not worth it. I promised myself to stop tearing good rare car in competition.

So, this journal will be about this one:

I don't plan anything extraordinary, it's not going to be record breaking project, rather story full of pain and suffering about fixing old cars
hope you like it.
Attached Thumbnails
Homebuilt GC8 for Time Attack-20150213_141432.jpg  

Last edited by -mav-; 03-05-2015 at 07:06 AM..
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Old 03-03-2015, 04:29 PM   #2
Join Date: Oct 2011
Location: Cyprus
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Posts: 164

So, in 2014 my best time was 1:12.73 with following specs:

1997 Impreza STi Typre-R, Version 4
EJ20K engine, VF22 Turbo, stock STi Yellow injectors (I believe 440s), ESL-upgraded ECU running @1 bar boost
Stock V4 intercooler, stock full intake incl air box with air filter
Magnecor competition 8.5 mm spark plug wires
Redline 10W-40 fully synthetic oil
Unknown stainless steel exhaust manifold, 4-in-1 design, 3-inch turbo-back custom exhaust with 200 cpi sports cat
Whiteline roll center andjustment kit
Whiteline front 22mm and 24 mm rear sway bars set to max soft*
BC coilovers Type MH inverted type, pillowbal adjustible top mounts F and R, 5/4 kg/mm springs
Hardrace rear trailing arms and adjustible track arms (more camber adjustment) with hardened rubber.
ALL other rubber parts in suspension and engine/transmission mounting are replaced with STi Group N parts.
Coilovers set almost to max hard setup 27/30 - F and 25/30 R.*
Camber -2.0 F and -2.5 R
Stock GC8 STi brake setup with 4-pot front and 2-pot rear calipers, vented front and rear discs, EBC yellow stuff pads all around and new unbranded "performance" grooved brake discs
walbro 255 lph fuel pump with wrong in-tank fuel filter causing starvation in right turns with less than 3/4 fuel in tank and super-cool custom anti-surge tank which made problem even worse...**
Advan RG-like replica wheels (9kg) with Dunlop Direzza DZ03G (H1 compound) in stock size 215/45 R17. Slightly rubs inner fender in front due to less ride height .
Exterior - original V4 Type-R exterior, except for e-bay fiberglass JUN-replica front lip.
Stock STi V4 5-speed transmission with DCCD
Stock diff (R180) with LSD overhauled using original STi LSD overhaul kit*
Motul transmission oils where applicable
MapDCCD controller adding automatic center diff mode - great tool, really allows you to use AWD on GC8
RaceDAC data aquisition system allowing to record 8 analogue data channels and 2 digital channels, with built-in 3-axis G-sensor and supported by RaceChrono - great tool to measure and improve your performance.
VDO oil temp and oil pressure gauges mounted in original gauge pod
fuel pressure sensor connected to oil pressure gauge trough 2-way switch, also logged by RaceDAC.
All the rest is stock.

Last edited by -mav-; 03-04-2015 at 03:06 AM..
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Old 03-03-2015, 04:53 PM   #3
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That's awesome, would love to do that some day.
Congrats on your racing results, nicely done!
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Old 03-04-2015, 02:47 AM   #4
Join Date: Oct 2011
Location: Cyprus
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About white car. It's 1996 with stock EJ20G, wrx 5 spd tranny and R160 diff. Bought together with my friends for trackdays as joint project but finally ended up on my driveway after rest of participants lost interest or got their own cars.
in fact I was trying to sell it to get something n/a rwd for this season but offers were too low. These cars are quite cheap here, so after lots of time and effort invested in it I couldn't justify selling for price offered...

The plan:

Swap coilovers, sway bars and rear arms from STi and putting stock STi psrts back on the black car.

Check ECU for compatibility and install ESL daughterboard for pre 96 cars
WTA intercooler - it's quite hot here so I thought that it might be useful. Also that's something I always wanted to do. I even got some bits like temperature controller. Thinking about frozenboost coolers, the only problem might be limited space on phase 1 engine. type 13 core will definately fit, but it's rated up to 350 h.p. which is not really far from oem setup. Even if I will drop this idea I will use controller for automatic intercooler water spray
Aircon will be removed for weight reduction with chargecooler radiator fitted instead of aircon one.

interior should be stock as per regulations, except for bucket seats, so I plan to get harness bar and driver bucket seat (I already have OMP harness installed)

Car has yellowstuff pads. Will probably delete abs (not working anyway). Considered 4/2 pot swap, but not sure if it's worth it.
Possibly cooling ducts.

Same as in 2014.

reverse scoop if get chargecooler installed
will remain without wing - imo only adds weight on this track
fog lights will be removed.

Unfortunately no dccd here, will try to swap RaceDAC from black car ir get another one. Racing without datalogging is not that fun

right now I'm trying to swap suspension and it appears to be a major challenge... progress post later...
and btw, first race is on Sunday
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Old 03-04-2015, 10:21 AM   #5
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Why not convert it to rwd? People do it all the time. Love the video btw!
Gotta get me car running

Last edited by KruseMissile; 03-04-2015 at 10:22 AM.. Reason: Just remembered that it wouldn't be in the same race class
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Old 03-04-2015, 11:48 AM   #6
Join Date: Oct 2011
Location: Cyprus
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Well, I don't think it will be competitive in time attack then
I wanted to get mk3 toyota Mr2/MRS. I like tricky platforms and MR layout is one of the things I wanted to try...
There's something in underpowered cars when you can floor it throgh turns trying to keeping momentum and concentrating on steering. There is cool mx5 competition here, they have their own cup. But I can't fit in these cars
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Old 03-04-2015, 04:38 PM   #7
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Nice Rides. Wish my local track had nice curbs like that..damn
2000 SRP Flared NV Auto Built Time Attack 2.0L vf39'd, 02 WRX Wagon, 05 xt Forester!
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Old 03-05-2015, 02:49 AM   #8
Join Date: Oct 2011
Location: Cyprus
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Thanks! Well, this is the only "big" track here in Cyprus, build with drift in mind, but it's great to have it! )
There is also one quite big cart track here, need to visit it sometimes, it used to held time attack events in the past...
Cyprus has great rallying history, it used to host WRC events in the past (only ERC now). Lots of cool gravel roads. Also there are a lot of competition in Hill climb championship, mountain roads are very nice here. I'd love to try it some day, but you really need a caged car, that's not for amateurs. You can spot some great cars there, some of them are also competing in Time attack events. If anything goes well, I will make some photos on Sunday.

So, back to topic. I wanted to swap all suspension bits from STi last Saturday... well, saying that I was too optimisstic is wrong. I failed. In fact on saturday I only managed to find nice looking turbo-back exhaust, bring it home and clean original STi suspension bits I had laying on the shelf for a while. I tried to catch up on Sunday, but... I couldn't break loose subframe bolts on track arms and knuckle bolts of trailing arms of the white car. I worked untill 3 a.m. the day befor yesterday and currently I only managed to remove rear coilover struts and sway bar from STi and put original bits back

This is my driveway where I work on both cars (they parked back-to-back currently)

[CENSORED] bolts...

Coilovers vs. OEM struts and springs.

Catch of the day

So, my plans changed… I have about 6-9 hours left to work on the car. Being realistic I dropped the idea of changing arms. Plans updated.

Front coilovers and sway bar are getting removed off STi. Need to put stock parts on STi not to leave car disassembled. If I have time - rear coilovers and sway bar will be installed on white car

everything goes on white car. Remaining struts, sway bar(s), exhaust, intercooler...

Wheel allignment, finishing works…

Wait, did I said “intercooler”? Yes, I bought new intercooler!


Yes, in this journal new parts may look like this…
I removed my intercooler to unbolt one of downpipe nuts, and I found that blow-off flange was broken by someone who did this before.. I really wounder how it held any boost pressure at all. I went looking for replacement and found this one. It’s same as mine but In better condition anyway. [/FONT]old one:

Bad photo, but it snapped right after 90 deg bend...

The tank will be used as expansion tank for chargecooler setup or (most lkely) for intercooler water spray system. It was the only one they had complete with the pump for the moment...

Last edited by -mav-; 03-05-2015 at 07:11 AM..
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Old 03-06-2015, 12:55 AM   #9
Join Date: Oct 2011
Location: Cyprus
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managed to get front suspension components removed
New ride height

Just before I got coilovers I thought that stock suspension is fine for me, but I wanted more camber. So I got mooresport top mounts. These are great parts, but I wasn't aware that I won't be able to use them with stock springs because they add about 30 mm of ride height. After I got coilovers they came with their own top mounts so these left attached to original struts. Wanted to put my my Group N top mounts but they are currently installed on white car and I had no time for swaping it.

It looks like my R160 diff might have limited slip in it. it was painted black by someone, but under the paint I found badge with letters "TR". Any ideas what it might mean?

So, for this nigt I have big plans...
Swap coilovers into the white car, swap sway bars, install exhaust which I haven't test fitted yet (but it was removed from same car, so hope it will be fine)

Need to clean coilovers before intallation and somehow make a guess on ride height.. After making allignment it cannot be changed. So basically I have one shot. Probably take measurements on current settings and add 5-10 mm... STi was sitting quite low, but it had ALK installed. I plan to get ALK for white car as well, so it will be interesting how it's going to affect cap times ))

Asked in some shops about conerweighting the car, but it seems that "ain't nobody got time for that!"
need to find somebody with the scales...

All mounting hardware and subframe/diff bushes look terrible on white car, probably will order all suspension/subframe bolts and bushes. Group N kit was kind of expensive... Anyone can advice cost effective bush kit for track car?

P.S. I like my storage room )
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Old 03-06-2015, 04:11 AM   #10
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Man, I just read through your whole journal and that's some awesome stuff! Love that you have kept it simple but yet your still making gains/records at the track. What is the track name?

Education is when you read the fine print; experience is what you get when you don't.
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