|
|
|
|
Thread Tools | Display Modes |
09-21-2010, 08:51 PM | #51 |
Scooby Newbie
Member#: 222641
Join Date: Sep 2009
Chapter/Region:
MAIC
|
If anyone is interested I am selling my Raptor SC kit, PM if interested.
* Registered users of the site do not see these ads.
|
09-21-2010, 09:47 PM | #52 | |
Scooby Newbie
Member#: 206040
Join Date: Mar 2009
Location: Carlsbad, CA
Vehicle:2009 Audi A4 2.0T APR Stage 1 |
Quote:
10-12PSI on stock 2.5i internals with just a good tune and exhaust components for a DD I think is a pipe dream dude. |
|
09-22-2010, 12:04 PM | #53 |
Scooby Specialist
Member#: 223032
Join Date: Sep 2009
Chapter/Region:
MWSOC
Location: Milwaukee (West Allis), WI
Vehicle:2006 Impreza 2.5i CGM |
what makes the internals so brittle? so long as youre not detonating, they should take it just fine. im not saying im right, but what makes them so weak?
|
09-22-2010, 01:18 PM | #54 |
Scooby Newbie
Member#: 206040
Join Date: Mar 2009
Location: Carlsbad, CA
Vehicle:2009 Audi A4 2.0T APR Stage 1 |
They are just not made for boost... Some people argue 5 psi is ok with good EM.. that's not even proven. I would be willing to say 10-12 PSI bone stock internals, exhaust and EM would make a very problematic daily driver.
|
09-22-2010, 01:51 PM | #55 | ||
Scooby Specialist
Member#: 1853
Join Date: Jul 2000
Chapter/Region:
TXIC
Location: SA-TX (Hozer expat)
Vehicle:GC6 Supercharged STM |
Quote:
Some people are still running on a Ludespeed Turbo kit at 6psi after many years. A few are still running a FAT stage 3 with no issues. Some people blew up their 5psi DIY kit after 2 months. Others still have had 10psi for years. I've been running 5psi of Supercharged boost for 2 years now. None of which is proof, just examples. The trend does however seem to be that less people have trouble at or below 6psi. It's become the accepted recommended boost level for the NA scoob. Not a rule, just a norm. Then there is the change in Pistons for the.. what was it.. '05 model? Plenty of reputable people saying they were even less forgiving on boost. In other words, there is no hard-and-fast rule! Just guidelines and a rule-of-thumb. Quote:
Target 10-12 psi if you have a power goal in mind. Fair enough. But, if your just looking for a bit of fun and an increase in power, KISS (keep it simple) and just do the lower 5-8psi. It's just proven to be less likely to go Kaboom when compared to the higher boosted NAs. Last edited by Skidd; 09-22-2010 at 01:57 PM. |
||
09-22-2010, 02:02 PM | #56 |
Scooby Guru
Member#: 60082
Join Date: Apr 2004
Chapter/Region:
MWSOC
Location: Minnesota
Vehicle:2004 Forester STI Silver |
The main issue is the fuel used. It isn't able to support high compression and any reasonable amount of boost before igniting by itself. This is why the turboed cars run 8.0:1 to 8.5:1. You can step to another fuel, E85 for example, and you can get more of both. E85 will let you run stock 10:1 and add up to a couple bars of boost without detonating. However, if you're stuck with 91 octane, you're only option to run any significant level of boost is to drop static compression. Can you run boost with the stock internals, sure. You just can't run much, and not much boost equals not much gains either for the money you're putting into the mod. In retrospect, you can completely rebuild the motor with lower compression pistons, buy all the necessary turbo hardware, and run a more appropriate turbo package on pump gas for less and while making another 50% power over what the high compression, low boost setup can do.
I do question the fragility of the stock internals. I would say the pistons are not specifically designed for it, but the main issue is people attempting to crank up boost and timing and repeatedly getting knock. This is how internals break very easily, even on WRXs and STIs. |
09-22-2010, 04:44 PM | #57 | |
Scooby Specialist
Member#: 102984
Join Date: Dec 2005
Chapter/Region:
MWSOC
Location: Northbrook, IL
Vehicle:2005 2.5RS 4EAT Platinum Silver |
Quote:
|
|
09-22-2010, 04:55 PM | #58 | |
Scooby Newbie
Member#: 206040
Join Date: Mar 2009
Location: Carlsbad, CA
Vehicle:2009 Audi A4 2.0T APR Stage 1 |
Quote:
|
|
09-22-2010, 05:27 PM | #59 |
Scooby Specialist
Member#: 187834
Join Date: Aug 2008
Vehicle:06 2.5i impreza Red |
This is true but with EM being even better these days those risks can be taken. The Cobb unit I have is an amazing piece of hardware that's 1 for fighting det. My 2 core intercooler which drops intake charge by a good bit is 2. Me running 93 oct. Down here is 3 with an occasional 103 oct fill up every once in a while is 3. My colder plugs that I'm running is 4. With 2 and 3 that is fine for say 7 psi of boost. Again I don't gave to worry about boost spike on a SC. There is a guy running the kit 2 years running on 9 psi on an ej20 no issues. Along with my walbro and 440cc injectors I don't think I'll have a problem with running 9-10 psi. I can honestly say next year I want my built tech works block so the need to worry about motor isn't there for me. She is a DD but I also own a wrangler lifted jeep and a gixxer 600 so I gave loads of transportation just gottah pick one that's all. When built block comes she'll be at 14 psi and crazy fun. Right now it's fun on it's own.
|
09-22-2010, 05:34 PM | #60 |
Scooby Specialist
Member#: 187834
Join Date: Aug 2008
Vehicle:06 2.5i impreza Red |
I think it's also for the factor of not many n/a set ups are boosting. Or the blocks at least. With work the blocks can run fine with not a care in the world. That with forged 10:1 pistons and or not rods it's a beast. 2.5i internals are actually really nicely put together. Bearings seem to be better rods and crank too. Once timing is right pistons work just fine with no issues. And that's with getting a good tune and leaving everything as is. Not messing around with it. People seem to think you have to keep playing with tunes once there set. Not true. Once it's tuned just oil maintenance is needed. My motor is at 19k I really think she will last till next year when new block is in. Low
Mileage helps my issue aswell. |
09-22-2010, 07:22 PM | #61 |
Scooby Specialist
Member#: 223032
Join Date: Sep 2009
Chapter/Region:
MWSOC
Location: Milwaukee (West Allis), WI
Vehicle:2006 Impreza 2.5i CGM |
your tune will definitely have to change along with the weather unless you run it conservative enough. if you think otherwise then you're wrong.
|
09-22-2010, 07:27 PM | #62 |
Scooby Specialist
Member#: 41986
Join Date: Aug 2003
Chapter/Region:
NWIC
Location: Hillsboro, OR
Vehicle:'06 STI/'85 Brat |
Wow, a mention of the FAT kit. That takes me back...
Jacob |
09-22-2010, 07:35 PM | #63 |
Scooby Specialist
Member#: 1853
Join Date: Jul 2000
Chapter/Region:
TXIC
Location: SA-TX (Hozer expat)
Vehicle:GC6 Supercharged STM |
|
09-23-2010, 02:03 AM | #64 |
Scooby Specialist
Member#: 187834
Join Date: Aug 2008
Vehicle:06 2.5i impreza Red |
I think other wise actually..I live in the tropics..its 80 degrees year round minus maybe lowest of 70 during the winter..and 95 during the summer. Again conservative should be every tune unless your building a race car lol Other than that its based on sea levels and what not..where as my highest peak might 1500 ft ASL and there aren't any cars going that high only wranglers in off road conditions..so say 1000 feet above for me to 0 at sea level. Until I have an issue or anyone else around with Subbys here in the islands then I'll take your word for it. Until then its get a good tune and leave it alone..maybe adjust for oct. levels but mostly its 93 and I'm sure the computer ca naccount for the fuel so no real need to adjust with software.
|
09-23-2010, 08:58 AM | #65 |
Scooby Specialist
Member#: 223032
Join Date: Sep 2009
Chapter/Region:
MWSOC
Location: Milwaukee (West Allis), WI
Vehicle:2006 Impreza 2.5i CGM |
well arent you lucky, mr. nice weather all year round. yes, that is me being jealous.
the problem with where i live is that its 80* outside in summer and 15* in winter. given that, i make more boost and command more timing in winter. under the wrong situation that means my motor just blew up. |
09-27-2010, 02:57 PM | #66 | |
Scooby Specialist
Member#: 201277
Join Date: Jan 2009
Chapter/Region:
MAIC
Location: Northern VA
Vehicle:2008 08 QSM 5MT LGT QSM |
Quote:
Cast iron or grey iron and cast Al have the same shear strength characteristics that are great for low impact infrequent acute forces not high boost detonation |
|
09-27-2010, 04:51 PM | #67 |
Scooby Specialist
Member#: 102984
Join Date: Dec 2005
Chapter/Region:
MWSOC
Location: Northbrook, IL
Vehicle:2005 2.5RS 4EAT Platinum Silver |
Neither of the USDM WRX or STi pistons are forged.
Rods are different from 2.5RS to WRX/STi but I don't think they're forged either. EJ Cranks are the same throughout. Materials-wise, EJ engines are very, similar, the biggest differences are this: 1. Piston face and Compression 2. Open-deck design Suffice to say: #1 matters the most. People in the past have blamed the lack of boost-ability of the N/A blocks due to the open-deck design, but the true issue is actually the compression. 10:1 static compression with 5 psi of boost is a LOT to ask for even on built engines running pump gas. It's just the limit of physics, ie Ideal Gas Law. And that's only figuring in static compression. I assure you the N/A piston face is quite different from the turbo pistons. This makes dynamic compression very high, and adding boost is just a bad idea. While superchargers are pretty cool, this supercharger is just in essence a belt-driven turbo. I wish beyond wishing that I could use this viably, but in my head the math doesn't add up. On the other hand I would love to see someone use this kit on a WRX block and pistons, and see what happens. |
09-27-2010, 05:24 PM | #68 |
Scooby Specialist
Member#: 223032
Join Date: Sep 2009
Chapter/Region:
MWSOC
Location: Milwaukee (West Allis), WI
Vehicle:2006 Impreza 2.5i CGM |
assuming im coming from a car with hypeuretic pistons that break the top of the piston off in the 1:00 area whenever you run too much boost (heat) because of the piston ring gap closing up and snapping off the top skirt of the piston...what makes these more prone to 'sploding? i dont care for forged things, they just cost more and are just as easy to break if your tune isn't in check anyway. yeah, they'll take a hit or two, but they'll still bite the dust under severe detonation.
yeah, you can always lower the compression ratio and run more boost...but what fun is that? the problem with low CR cars is that out of boost they SUCK for driveability. given that you put enough money into the motor to run a good amount of boost (~15psi) the high CR car would not only make great amounts of power, but it'd drive very nicely even just cruising. i get that 10:1 is high, but there is no way in hell that if you put ported heads, cams, and a nicely sized header/intake combo that you couldnt run at least 10 pounds of boost on the car. i'm thinking it'd take more. also, the CSC setup this kit actually is outdoes any other blower out there by miles. roots blowers suck and turbos are somewhat 'random' at times. a supercharged setup is always predictable and very easy to tune with the linear powerband it creates. |
09-27-2010, 09:38 PM | #69 | |
Scooby Newbie
Member#: 206040
Join Date: Mar 2009
Location: Carlsbad, CA
Vehicle:2009 Audi A4 2.0T APR Stage 1 |
Quote:
If I remember correct it had a larger GT35 turbo and so the supercharger, when the switch was turned on, gave it the instant power and TQ while quickly fully spooling that large turbo for no lag. EDIT: their 2005 shop car was actually twin turbo and super charged too with dual GT30R turbos. Last edited by Audi20Tdriver; 09-27-2010 at 09:44 PM. |
|
09-27-2010, 09:59 PM | #70 | |
Scooby Specialist
Member#: 102984
Join Date: Dec 2005
Chapter/Region:
MWSOC
Location: Northbrook, IL
Vehicle:2005 2.5RS 4EAT Platinum Silver |
Quote:
I also forgot about how Subarus have a very unoptimized CC design. Normally, I would say, "Yes, I'm all for that, and it's all possible!" but these engines are too detonation prone because it the CC. Lower Compression Ratios such as found on WRX and STi are not as bad as one might make it out to be. Sure they're kind of crappy as they are stock, and back when it was the 05 models with the 2.0L peaky thing with a wanky turbo... not my cup of tea, and insurance was too much... However, I recall williaty saying he built an EJ257 with PnP heads, intake, turbo outlet, and some extra other stuff to reduce power lost when off boost. He said it was the first turbo car he actually didn't absolutely hate. Knowing him, that means a lot. I recall him saying that it felt N/A when off boost and had nice power when the turbo started to roll in. In the end, I feel like this is a better option overall, and cheaper, and you still win in the end. |
|
09-27-2010, 10:53 PM | #71 | |
Scooby Newbie
Member#: 222641
Join Date: Sep 2009
Chapter/Region:
MAIC
|
Quote:
|
|
09-27-2010, 11:34 PM | #72 |
Scooby Specialist
Member#: 102984
Join Date: Dec 2005
Chapter/Region:
MWSOC
Location: Northbrook, IL
Vehicle:2005 2.5RS 4EAT Platinum Silver |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
what can you do to a 2006 2.5i to be faster? | ro0kie | Newbies & FAQs | 52 | 10-18-2009 10:57 AM |
What can i do to my 2006 2.5i to increase HP? | 2006-2.5i | Normally Aspirated Powertrain | 22 | 10-13-2006 01:24 PM |
good exhaust for 2006 2.5i? | 06suba | Normally Aspirated Powertrain | 1 | 02-10-2006 10:46 PM |
Block Heater Installation for a 2006 2.5i Imprezza | amorak | Normally Aspirated Powertrain | 6 | 10-30-2005 01:53 AM |
2005 2.5RS or 2006 2.5i or 2006 2.5 wagon | Prelude | Canada Region Forum | 16 | 09-21-2005 04:10 PM |