25

Steve’s STi: Doing It Right!

by Frank Ewald 

In 2003 the sparkling new, blue Subaru  WRX STi contained enough power and handling to more than challenge Steve’s driving capability. Driving off the lot he knew that he had purchased an amazing car and that it had so much more power than he would ever fully utilize and that the AWD capabilities meant that he would have control in all situations. Then he started going to autocrosses and high performance driving schools. After that, there was no turning back. The curse of car modification hit – and it hit hard – and as the weaknesses of the once amazing STi were found, fixes were sought. Over the last decade Stephen Deneka’s Subaru WRX STi has been rebuilt into a fine machine, but over the last three years it has been transformed into a beautiful machine that almost defies belief.

 

There's no challenge recognizing this car as a Subaru WRX STi. The wing, splitter, and cage indicate that it has been "lightly" modified from when it left the showroom floor in 2003.

Steve’s STi was one of the first STi’s in Canada and he picked it up on June 30, 2003. It was a 2004 model. He was so impressed with his purchase and with this amazing performance machine that he took it out to a local track (Nelson at Shannonville Motorsport Park) with the thought, like everyone else who heads to the track for the first time in their amazing performance car, that he would blow the doors off of everyone who would ‘oooh’ and ‘aaahh’ at this amazing machine, fresh off the boat from Japan. Instead, he was beaten by his buddy Daniel who was driving a mere WRX. That was a turning point and the start of an ongoing passion for track schools. He took all instruction that was available – 25 schools between 2005 and 2006. He did not stop there, he then began instructing at the schools, and then began organizing them. Steve started participating in AutoSlalom in 2005, Navigational Rally events in 2006, and in 2006 also began participating in Ontario Time Attack events.

 

Sitting trackside at Canadian Tire Motorsport Park during a CASC event and you can sense that this car wants to be out on the track! I'm certainly looking forward to seeing it fly by the next time I'm on track with Steve.

The STi was a brilliant purchase because Steve knew that it came prepared from the factory for the kind of driving that he was going to do. He was not going to modify it nor allow anyone else to modify it. That, however, was before he got so actively involved in motorsport events. As his driving skill improved Steve began to see the inherent weaknesses of the car. For example, the 2004 model was very prone to understeer (a Cusco front differential later improved that), the suspension was too soft and squishy, and – of course – it simply did not have enough power! That began what will likely be a lifetime of upgrades and changes. We will document a few of them here.

 

I don't know about you, but I love being near corners and watching the cars as they fly by. Some struggle, some float through, and then there are cars like Steve's STi. It's made for the race track and you can tell. What an incredible car!
 
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Comments
Grigore
Grigorelink
Tuesday, January 06, 2015 3:28 AM
What is up with these re uploads?
nissannx
nissannxlink
Tuesday, January 06, 2015 3:48 AM
Grigore, this isn't a reload. In the editing stage it was posted before it was ready and removed a couple of hours later. So if you saw it, that was pre-production. This is the edited draft. Sorry for the inconvenience, but I am fussy about ensuring accuracy in fact and writing. So is the rest of the MotoIQ team.
spdracerut
spdracerutlink
Tuesday, January 06, 2015 10:02 AM
Looking at the engine bay pictures... I was thinking something looked odd. Tubbed out! Ha! I think that's a first I've seen on a STi.
Empty Garage
Empty Garagelink
Tuesday, January 06, 2015 10:54 AM
I believe you are incorrect in the tires:
295 30 18 Yokohama A048s

Those look to be AD08 or ADO8R tires in the top picture of Page 6.

AD08 R
http://www.tirerack.com/tires/tires.jsp?tireMake=Yokohama&tireModel=ADVAN+Neova+AD08+R

A048
http://www.tirerack.com/tires/tires.jsp?tireMake=Yokohama&tireModel=ADVAN+A048
nissannx
nissannxlink
Tuesday, January 06, 2015 11:27 AM
Hey EG, you're right! Those aren't track tires and I believe they are AD08s. However, on the track he uses A048s. In the pic you're referring to (an I think all of the stationary pics) he was preparing to leave the track thus had his street tires on. I didn't include that in the article. Hope that helps.
Steve - Slowpoke842
Steve - Slowpoke842link
Tuesday, January 06, 2015 8:17 PM
Good eye, E.G. AD08's were mostly for transit to/from the track, but had to be used at Grand Bend due to logistics issues and the different tire rules between the two main series we run, and the tires available to us. Due to changing rules and strategy from year to year, we had duplicate sets of AD08 and A048 in both 265/35/18 and 295/30/18. I'm hoping we can get some A050 softs in North America next year! Those World Time Attack teams hogged them all this year. :)
revoltrise
revoltriselink
Tuesday, January 06, 2015 9:08 PM
That's not duct tape. Racecars don't get duct tape. They get high speed tape, because racecars.
Mike Kojima
Mike Kojimalink
Tuesday, January 06, 2015 11:52 PM
To the big tires cause wheel bearing or piston knockback issues?
nissannx
nissannxlink
Wednesday, January 07, 2015 4:19 AM
spdracerut - it's true but the build is so good that you're trying to figure out what's going on!

Steve - Slowpoke842, thanks for joining in. Since it's your car you'll be able to answer some of these questions without me calling you up and picking your brain!

revoltrise, I stand corrected. You are right, it must be high speed tape! ;)

Mike, I'll leave that question to Steve - because until he allows me to be a co-driver I won't have personal experience with those questions!
Trofeo
Trofeolink
Thursday, January 08, 2015 9:29 AM
Why be so clandestine about the dyno sheet? 450whp, even 550 whp isn't anything great on a sleeved, forged Subaru. Water injection??? seriously? The article states he runs 109 octane fuel, is WI really necessary? I'd like to see dyno runs with and without WI on 109 octane. I ran water injection.....10 years ago. Then this new fangled thing called E85 and E99 became readily available.
Next time do an article on Element Tuning's STi, and spare us readers the pain of 15 fender flare, engine bay and "tub" shots.
nissannx
nissannxlink
Thursday, January 08, 2015 10:18 AM
Trofeo, blunt and to the point. I'll take those into consideration for future. Gaithersburg is a bit far for me, but maybe ...
Mike Kojima
Mike Kojimalink
Thursday, January 08, 2015 5:53 PM
Subarus are not reliable at the 550 hp mark in a real road racing environment no matter how you build the bottom end.
Steve - Slowpoke842
Steve - Slowpoke842link
Thursday, January 08, 2015 7:26 PM
Mike Kojima: I was not expecting to make it through the season on one set of wheel bearings, but that certainly was the case. Granted, we only got into stickier compounds at the end of the season. We'll do preventive bearing change before starting the Ontario 1500 for sure. As you likely guessed, we're running the 5x114.3 hubs and bearings. Previously I had run SixGun Racing 5x100 bolt spacing with 5x114.3 bearings, so my thrice a season bearing changes ended a while ago.

Pad knockback since going to the StopTech calipers is less than I had with the stock Brembos, but I picked up the habit of left-foot brake taps before critical braking zones years ago with the 5x100 bearings. My co-driver Trevor doesn't do that and doesn't notice the very mild knock-back. Good ducting to keep hub temps cool and SRF fluid for fade resistance certainly helps the braking feel.
Steve - Slowpoke842
Steve - Slowpoke842link
Thursday, January 08, 2015 7:41 PM
Trolleo: You're probably not familiar with things north of the border, but E85 and E99 are not easy to source here, and water absorption and separation become an issue. MS109 makes great torque and doesn't suffer major storage issues.

My favourite track here is Mosport (now called Canadian Tire Motorsports Park) which has an approximate 25 second successive gear dyno pull leaving turn 5C at the torque peak of third gear on an uphill climb and finish into the braking zone of turn 8 at the HP peak of sixth gear. Though water injection isn't needed for knock resistance, it's used to drop EGT's. FYI: That's a good thing when you basically run full throttle at high load for 25 seconds.

For the Ontario 1500 we'll have to run a spec fuel which will likely be 91, 93 or 94 octane pump fuel from random stations around Southern Ontario. Once we find out what that fuel is, we'll put in a tune that's closer to the edge of what I normally run with race gas and run pure meth through the Aquamist system. I won't rely on even a good water injection system for a base tune. For me, an aftermarket water injection system will always be added safety, not required to avoid random pieces of metal leaving the block at inopportune moments.

As for WHP... I have honestly disclosed 1300cc injectors, race gas, BW S300SX 8375, 2.5L of displacement, cams and upsized valves in the ported heads, Full race twin-scroll set up and a 3" exhaust. You tell me what horsepower I can make for road race conditions.
Steve - Slowpoke842
Steve - Slowpoke842link
Thursday, January 08, 2015 7:44 PM
Seems I can't edit. Hrmm.. I meant leaving turn 5B. My bad.
Trofeo
Trofeolink
Friday, January 09, 2015 9:38 AM
Slowpoke842-If you have access to VP 109, there must be a dealer nearby, why not switch to VP C85? Poor storage and handling shouldn't be the deciding factor is what fuel you use. Both ethanol and oxygenated fuels (E10, VP109) are hydroscopic.

The twin scroll turbine is probably your limiting factor, not the compressor's flow. That coupled with a conservative tune? (contributing to your high EGT's, or too small of a turbine housing?) I'd estimate you're around 475 whp, ~400 wtq on VP109 with methanol injection (Dynojet numbers). You aren't injector limited, that's for sure. It's a tough balance between best turbine housing size and transient response.

Most high HP Subaru engine's fail from issues related to oil pressure/flow, lifting the heads from very aggressive antilag (which you shouldn't have with the Cobb 14mm studs) or trying to make competitive drag race numbers (900+ WHP). I'd sell the Cosworth manifold, buy an NA 2.5 manifold (since it flows similar CFM)and use the remaining funds on a dry sump system. Or at minimum a ported oil pump, shim the relief valve and maybe throw in an Accusump for good measure.

EGT numbers (like other pertinent information) are nowhere to be found in the article, but I'm pretty sure your stainless exhaust valves and Inconel turbine wheel can handle the heat, even in a road race environment. It sounds like the WI is treating the symptom and not the problem. There is no reason a properly built, properly tuned Subaru engine should melt down, especially in a cooler, northern climate.
Trofeo
Trofeolink
Friday, January 09, 2015 9:53 AM
Sorry to troll, but I don't want to see MotoIQ turn into another website that writes articles for the ADD/LCD-Instabook-millennial-dorifto crowd. Some of us still nerd-out to alignment settings, dyno numbers, lobe separation, compression ratio's, etc. etc (ad nauseam).
nissannx
nissannxlink
Friday, January 09, 2015 10:38 AM
I'm probably one of the least technical writers for MotoIQ, so I appreciate that insight Trofeo. I hope that my articles don't ever become boring - as they are usually about vehicles and motorsport related activities that I enjoy. And hopefully readers will also.
And honestly, I could look at the tubbed wheelwells a lot more.
Trofeo
Trofeolink
Friday, January 09, 2015 2:46 PM
Nissannx-I'm not trying to tear apart your article, maybe I was a bit too harsh. Tubbed wheel wells are far better than 50+mm wheel spacer when fitting large width wheels/tires. Keep the motorsport articles coming, but maybe incorporate more technical info, maybe owner provided engine/chassis build photos, etc. Give the reader something to aspire to as opposed to making the car seem financially unattainable.
Trofeo
Trofeolink
Friday, January 09, 2015 2:49 PM
Here's a link to an interesting article. Given all the hype on twin scroll set-ups, I like to throw this on the table for discussion or perhaps a future article.

http://www.racecar-engineering.com/news/racing-tech/boost-group-n-and-wrc-turbos/
Dan DeRosia
Dan DeRosialink
Tuesday, January 13, 2015 6:12 PM
Most high HP Subarus do not do roadrace duty. There's so many issues with the oiling system past what can be easily fixed with just changing the oil pump, and getting any boosted motor to reject heat at those sort of power levels is problematic at best. That and the EJ25 just gets really sensitive to all sorts of things because the bore is really too big. So yeah, water injection and high octane fuel to tolerate what internet car forums would consider modest power outputs completely makes sense... because there's a difference between going a quarter mile, or freeway onramp blasts, or one lap even... and doing multiple laps.

Seriously, look at how people who do actual roadrace stuff build their engines when they don't feel like hauling them home in a recycling bin every few events.
nissannx
nissannxlink
Wednesday, January 14, 2015 2:35 PM
Can-Jam has a lot of experience with Rally and Road Race engine builds. I'd be happy to have one of their engines and go road racing with it!

And Trofeo, I'll keep the articles coming. And I look forward to your comments. Valid points and I appreciate them! So keep them coming too!
nissannx
nissannxlink
Wednesday, January 14, 2015 2:37 PM
Valid points, Dan. Unfortunately I've seen a few Subaru's leave the track on flatbeds because they couldn't handle the cornering G-forces. That won't be Steve's Subaru! ;)
Steve - Slowpoke842
Steve - Slowpoke842link
Friday, January 16, 2015 6:42 AM
Dan: It was CanJam's success with the Versace Parfums cars at the same tracks I run at in endurance races that convinced me I needed their expertise. I am doing Time Attack at the moment, so maximum 10 lap practice sessions at this point, but I still wanted it built to survive sprint road racing sessions. They achieve a lot without going to full dry sump.

http://www.flickr.com/photos/ricardipus/5383057469/

I think Subaru's biggest mistake is not putting larger oil pans on these cars from the factory. The twin scroll headers also limit large pan choices.
Dan DeRosia
Dan DeRosialink
Friday, January 16, 2015 2:35 PM
My biggest gripe is the oiling layout in the stock cranks, but the ones with the good layout (basically Cosworth or Arrow) are big bucks. There's also a lot of other weird compromises to fit the engine between the framerails, and very few production engines do a good enough job cooling the valve seats to stand up to really high boost for a sustained period.

My point was really just that unless they've done it, everyone underestimates how hard it is to make engines live on a road course at full speed.
Micah McMahan
Micah McMahanlink
Monday, January 19, 2015 4:09 AM
Mike, I'll gladly disagree. A properly built EJ25 ran just fine in for three seasons in Turn In Concepts' Unlimited TA car (3100 lb piggy)...well, until the factory crank dampener chunked rubber at 8500 RPM at Road Atlanta hahaha (but that could have been avoided).

Fixing the shortcomings of an EJ engine is a hobby of mine.
Steve - Slowpoke842
Steve - Slowpoke842link
Tuesday, January 20, 2015 7:34 AM
Dan: Keeping the heads breathing well with a well matched hotside, good headers and the upsized valves and ported heads was a core priority. You're right, that's the reason for the double safety of race gas and water injection: low EGT's. Until you've done a few seasons of it and suffered the consequences, people really don't understand how seemingly "random" things can go wrong if you don't take every precaution. And it all is based on a conservative tune and HP goal.

Even on higher boost settings the EGT's are usually below 750 deg C in sustained sessions. We started in 2012 with a 1.00 A/R, but dropped to 0.88 in 2014 for faster response (1000rpm lower torque peak) and only saw slight EGT increases at the highest boost settings. The exhaust pops on shifts, but doesn't throw flames anymore since adding the water injection and tuning on the Vipec.

We seem to have some experienced Subie track people in these comments.... let me ask you something. I've had my stock transmission freshened twice over the years and when I look back at the data logs, I was able to do sub 0.20 shifts (loss of acceleration to resumption of acceleration) without a problem but now 0.20 is around the limit for where I might get grind. We think it's the Subaru superseded synchro parts number and that the original 2004 synchros had faster engagement.
Did anyone else who had an original 2004 gearbox experience the same thing when they freshened the synchros? I've tried a variety of straight transmission fluids and cocktails. Although I can make the situation worse, I can't get the same shift speed with the same fluids I ran before.

Another possibility is that it's the difference in mass from my old single plate four puck Bully clutch and 16lb flywheel compared to the twin plate I run now. Maybe having more mass and not decelerating as fast as the old setup and engaging at higher RPM? Maybe also some different throttle plate close characteristics when we switched from ECUTEK to Vipec?

Did anyone else find a difference in minimum shift speed after rebuilding their 2004 boxes?
Steve - Slowpoke842
Steve - Slowpoke842link
Tuesday, January 20, 2015 7:47 AM
A tip for the new guys starting out down the engine path with a budget... find an honest shop and builder with a good record of finishing the same type of events you'll be doing. Road race is different than drag and rally, and rally is different than everything else.

When I first started working with CanJam they asked me what my horsepower goal was. I responded "Three years". They looked at me a little baffled. "I want to make horsepower for three years without a failure. You tell me what that horsepower number needs to be." We've agreed that I'm probably going to need some bearing and ring freshening at a maximum interval of two years, and we're relying on oil analysis, dyno results and compression/leakdown to cue that. But it's a big price difference between freshening and failure. Start off conservative.
nissannx
nissannxlink
Tuesday, January 20, 2015 9:30 AM
LOL, Steve. I think "Three Years!" would have been the article title if you had told me this earlier! I love it!
Dan DeRosia
Dan DeRosialink
Thursday, January 22, 2015 5:38 PM
"1 year" is my goal for the rotary powered project I'm working on; I totally get that. I've done the math and can't afford to roadrace a turbo car, but freshening rotaries I can do in my sleep by now. ... well, also there's no place to race turbo cars around here without megabucks.
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