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Old 09-20-2005, 05:17 PM   #1
zzyzx
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Default Zzyzx Motorsports 2.5 RS breaks 300 NA HP

Here's the official Press Release. The dyno graph is posted here on the website.

Quote:
FOR IMMEDIATE RELEASE
September 20, 2005

Zzyzx Motorsports Impreza 2.5 RS breaks 300 NA horsepower

TechWorks Engineering (Calgary, Alberta, Canada), Dieman Motorsports (Lees Summit, MO) and Zzyzx Motorsports (Overland Park, KS) conspired to build the most powerful normally aspirated Subaru 2.5L Flat-4 in North America. At more than 300 CHP, the output shatters any previously documented efforts to date.

Utilizing an MD Mustang IMP dynomometer, the engine output hit 235 WHP at 6450 RPM and 209 WTQ at 4600 RPM. "We typically see 233 WHP for a WRX STi, which is rated at 300 CHP, comments Jake Diehl, owner of Dieman Motorsports. "This engine puts down roughly 185 WTQ at 2000 RPM and carries a nearly flat torque curve up to 4600 RPM where it makes 209 WTQ, then tapers off to roughly 185 WTQ at 6500 RPM. Though the peak of 209 WTQ is at 4600 RPM, peak numbers don't readily describe the output of this engine. There is more power under the curve than any stock STi can wish for. Based on the average WRX STi, WRX and 2.5 RS data for our dyno, we're looking at peak outputs of roughly 302 CHP, and 276 CTQ."

The longblock was built entirely by TechWorks Engineering. "The recipe for the engine is less exotic than most would guess.", comments Tom Penner, owner of TechWorks Engineering. This engine uses our off the shelf 11.2:1 CR forged pistons, Stage II SOHC Street cams and headwork to maximize both velocity and flow. We consider this a Stage III engine build as it requires high-octane gas and stand-alone engine management, but simply lowering the compression ratio would still yield impressive output in a more streetable configuration." The TWE headers are a race-only 4-2-1 design, with large primaries. "The design of the headers was twofold: to provide power up top, and to lower dynamic compression in the lower RPMs to avoid torque spikes and detonation.", comments Tom. The trough in the torque curve from roughly 3000 to 4500 RPM is a direct result of the header design.

"I knew we needed to find a different intake manifold as the pre-2005 designs clearly are not meant to make power up top; this is a well documented.", comments Steve Sulatycki, owner of Zzyzx Motorsports. "Looking over the options, it appeared the 2005+ 2.5 RS intake manifold design was clearly superior and I decided to mate a high-flow 65mm throttle body to the '05 intake manifold. I had no idea what kind of numbers we'd be making."

"Once the car made it's first 220+ horsepower pull with very little timing and 11.5:1 AFRs we knew we had a strong motor on our hands. I proceeded to level out the AFRs to a very conservative 12:6:1 AFR and we started making pulls in the 230+ WHP range.", comments Jake. "As this engine was built and is being used for road racing, we stayed with a conservative tune for longevity. This is no dyno queen, and these numbers are real-world, not one-offs."

"The engine makes power everywhere", comments Steve. "This kind of power is useable on the street, at an autocross or road racing. It's perhaps the most versatile power delivery you can ask for and the flat torque curve results in a very predictable and controllable chassis when you have the car at it's limits."

The dyno graph is available at the Zzyzx Motorsports website.

Contact Info:

Tom Penner
TechWorks Engineering
403-288-8568
http://www.techworkseng.com


Jake Diehl
Dieman Motorsports
816-347-1950
http://www.diemanmotorsports.com


Steve Sulatycki
Zzyzx Motorsports
913-706-5496
http://zzyzxmotorsports.com
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Old 09-20-2005, 05:22 PM   #2
SilverSurfer04STi
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Quote:
Originally Posted by zzyzx
Here's the official Press Release. The dyno graph is posted here on the website.
I like that type of power, but what is the approximate cost to turn a stock RS or i into this type of performer? Did they keep the stock clutch and trans?
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Old 09-20-2005, 05:55 PM   #3
jbotage9er
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neat! That makes as much NA power as a c4 vette 5.7L V8
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Old 09-20-2005, 06:07 PM   #4
AntiochCali
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Quote:
Originally Posted by jbotage9er
neat! That makes as much NA power as a c4 vette 5.7L V8
The torque curve for the C4 though doesn't drop off to 145 ft-lbs above 5000 rpms...it is relatively stable across the entire rpm band...it is great power for an RS though, really cool if it is an affordable kit.
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Old 09-20-2005, 06:15 PM   #5
zzyzx
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Quote:
Originally Posted by AntiochCali
The torque curve for the C4 though doesn't drop off to 145 ft-lbs above 5000 rpms...it is relatively stable across the entire rpm band...it is great power for an RS though, really cool if it is an affordable kit.


Are we looking at the same dyno graph? The scale is 2000 - 7500 RPM. The output is 145 ft-lbs @ 7500 RPM, not 5000.
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Old 09-20-2005, 06:19 PM   #6
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Awesome results Steve. The hard work is paying off!!!!

Jay Storm
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Old 09-20-2005, 06:19 PM   #7
8Complex

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Drop in pistons = $719
Stage 2 SOHC heads = $3244
Gasket kit = $200
Standalone = $1500 (guess)
Injectors & fuel pump = $200 (guess)
Clutch = $325

Total = about $6200



Looks like it'd be fun... perhaps a reflash, and possibly core returns from your stock heads, could make it more affordable.
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Old 09-20-2005, 06:38 PM   #8
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wow, that's impressive. I never would have guessed
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Old 09-20-2005, 06:57 PM   #9
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We need to know how this compare to the stock sti on the road. Any vid on the drive to show us that comparison?
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Old 09-20-2005, 06:57 PM   #10
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what year RS?
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Old 09-20-2005, 07:29 PM   #11
Patrick L
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Quote:
Originally Posted by rally_on
what year RS?
2000, it's the same RS on his website.
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Old 09-20-2005, 07:57 PM   #12
poormansporsche
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Things to add most likely...

My05 2.5RS intake manni
Custom throttle body
prolly new fuel delivery

cheers

garrett
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Old 09-20-2005, 08:05 PM   #13
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Quote:
Originally Posted by 8Complex
Drop in pistons = $719
Stage 2 SOHC heads = $3244
Gasket kit = $200
Standalone = $1500 (guess)
Injectors & fuel pump = $200 (guess)
Clutch = $325

Total = about $6200



Looks like it'd be fun... perhaps a reflash, and possibly core returns from your stock heads, could make it more affordable.

this can be done on a 2005 RS right?
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Old 09-20-2005, 08:07 PM   #14
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Hey TWE!

You need to get the intake below of the EJ204 and EJ254 from NZ, AUS or JP.

Its a variable intake that works very well over 200chp, 238cnm.

I would love this on my AVCS. Would be interested to see what the results really would be.



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Old 09-20-2005, 08:46 PM   #15
Kostamojen
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Cool, havent seen that intake manifold yet...
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Old 09-20-2005, 11:42 PM   #16
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Exactly what octane?
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Old 09-21-2005, 12:42 AM   #17
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Quote:
Originally Posted by mrubino83
So we know that it is a 2.5rs motor, stgII cam, Im gonna say PnP'd heads, new bottom end (any guesses on the C/R?) Im gonna say ( and this is just a wild guess) 11-1, and then the obvious:intake exhaust, header, new/flashed ECU, etc...
not a bad guess if I do say say so myself Nice work guys!!
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Old 09-21-2005, 08:23 AM   #18
insaneSTI
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what's it run in the 1/4
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Old 09-21-2005, 12:07 PM   #19
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Glad to see some of the details of the build put together. While obviously it takes some real money to make some real power, it also confirms my longheld belief that you can make some pretty serious power with what is essentially a stock bottom end. Our open deck Ej25 blocks are better blocks than most people give them credit for...
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Old 09-21-2005, 02:18 PM   #20
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never thought i would see the day...what octane is this at?
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Old 09-21-2005, 02:29 PM   #21
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I wonder how much hp would be lost if it were tuned to run on 91 octane? But then i guess we need to know what octane it was tuned on in the first place.

Great job kind of wish there were more NA build ups of subarus.
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Old 09-21-2005, 02:48 PM   #22
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*sports wood*
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Old 09-21-2005, 02:57 PM   #23
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i'd rather build up an n/a before doing an entire swap. i'm very interested in details and pricing.

josh
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Old 09-21-2005, 04:36 PM   #24
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Those are amazing numbers at the crank - 302hp & 276 ft-lbs. Which in a 2.5L engine means 120.8 hp per liter!!!

Imagine if the same results could be gained from doing those same mods to a 3.3L EG33! You'll be psuhing just 2hp shy of 400!!!
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Old 09-21-2005, 07:49 PM   #25
SilverSurfer04STi
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Quote:
Originally Posted by 8Complex
Drop in pistons = $719
Stage 2 SOHC heads = $3244
Gasket kit = $200
Standalone = $1500 (guess)
Injectors & fuel pump = $200 (guess)
Clutch = $325

Total = about $6200



Looks like it'd be fun... perhaps a reflash, and possibly core returns from your stock heads, could make it more affordable.
Kinda pricey, but not too bad. Especially considering the low price of an RS to begin with. Would love to drive it to see how it compares to a stock STi.
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