RS to a WRX
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Joined: Dec 2006
Posts: 670
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he's right. you CAN squeeze a few extra ponies, but it is only a few extra and without custom EM, internals, E85, and every suspension upgrade known to man you will never keep up with a stock wrx... forget about anything with so much as a Lev.1 Drivermod
I've got 125whp from my engine right now, 30whp+ stock. trust me, i can't wait for my swap... highest privately owned n/a 2.5 I've seen on any board was 158whp. Subiesport magazine a few months ago put out an article on building the 2.5, and after 10 years of working with the same engine design they FINALLY got it to break 200whp using custom standalone EM, E85(ethanol fuel), cams, heads, full intake and exhaust, upgraded fuel system, pulleys, and i think they had a nitrous kit hooked up, but didn't use it because of one reason or another, but i forget.
Anyway, unless you want to change your fuel system to E85 and have to drive, i think to Jupiter, FL to fill your gas tank.... i'd just go with a swap.
read up on Brake Specific Fuel Consumption on sl-i.net, it will give you alot of info on our engines concerning maximum power
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Joined: Dec 2006
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I hear ya man. If I were you I'd try to sell your engine and tranny to someone, or try to trade it and cash for the engine and tranny set that you want, I know alot of places take your old engine as credit if you have them swap the engine, and if the engine is in that good of condition they should offer you a good deal.
GL
GL
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Joined: May 2004
Posts: 434
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In case you choose to keep it N/A(what I want to do) here is a good read on making N/A power from NASIOC
N/A power white paper, long, please critique. - Normally Aspirated Powertrain - NASIOC
Exerpt(more in depth on nasioc):
In your searching (assuming you do any) you will find in every thread about N/A power at least one naysayer who calls you stupid for trying to make N/A power. Their solution is to always swap in a WRX motor or turbo your existing 2.5L motor. The argument being that it provides more power and is less expensive or a better value.
Here is my opinion on the issue. First lets address the cost issue. If you buy a USDM WRX motor you will generally spend $1500 -$3500 on the motor, this should include a wiring harness and ECU. This is money that is spent in one lump sum and is not always easy to do. These motors are almost always used so reliability is a concern. There are many threads of folks buying bad motors and having to chase down the seller to get their money back.
Additional associated with the swap include exhaust parts, uppipe, downpipe and turbo cross member. On top of that is the hours spent splicing the WRX wiring harness into your RS / L harness. For a first timer expect about 30 – 40 man hours. My time is worth about $40 an hour in my business that is an additional cost of $1200. So figure a full $4000 of real dollars as the swap cost. You may need driveline components as well.
With the swap you get a WRX engine that dynos at around 170whp. A stock EJ25 dynos at about 100whp. If you have an older Impreza your car is also lighter than current Impreza so power to weight becomes a factor as well. A 1996 – 2001 impreza only need about 150whp to equal the power to weight ratio of a bugeye WRX. I will illustrate.
A 1998 Impreza weighed about 2800 lbs ( the coupe and sedan less, the wagons more). Based on 100whp a GC style impreza has a p/w ratio of 28:1.
A 2002 WRX weighs about 3100lbs, with 170whp its p/w ratio is 18.24. To equal that p/w ratio the GC owner only needs 152hp at the wheels. This can be achieved with cams, intake, headerback and EM. New these parts would run about $2000. Do some smart shopping and your budget is closer to $1200. You also don’t have to spend the money all at once so you can use WAM (walking around money), those readers who are married know how important that can be. Keep in mind that these numbers assume the two vehicles are dyno on the SAME dyno under similar conditions. Dyno results varily widely from one dyno brand to another, one location to another and even the operator of the dyno can have and impact.
You also don’t have the down time of a swap. Parts can be bought and installed a little at a time, so the car is down for a weekend. Cams are the only parts that put you out for a week or so. The addition of heads can put the N/A owner close to WRX power levels. Coupled with the RS’s better gear ratios, a properly tuned RS can give even Stage 1 WRX’s a run for there money in most situations.
Auto-x favors the tuned N/A car. The WRX needs to spool out of every corner ( the ’06 model fixes this to some degree) unless left foot braking is well executed. The N/A motor sees good power from 2500 rpms to redline.
For the $4000 that a swap would cost a prudent N/A impreza owner should be able to reach the hi comp piston level of build, assuming the labor is DIY. This should give you at least 200hp at the wheels. Keep in mind that their only a handful of ppl attempting a build to this level and it can be time consuming. But a stock WRX needs a Stage 1 mod package to reach these levels, and at that the p/w ratio is still an issue.
N/A power white paper, long, please critique. - Normally Aspirated Powertrain - NASIOC
Exerpt(more in depth on nasioc):
In your searching (assuming you do any) you will find in every thread about N/A power at least one naysayer who calls you stupid for trying to make N/A power. Their solution is to always swap in a WRX motor or turbo your existing 2.5L motor. The argument being that it provides more power and is less expensive or a better value.
Here is my opinion on the issue. First lets address the cost issue. If you buy a USDM WRX motor you will generally spend $1500 -$3500 on the motor, this should include a wiring harness and ECU. This is money that is spent in one lump sum and is not always easy to do. These motors are almost always used so reliability is a concern. There are many threads of folks buying bad motors and having to chase down the seller to get their money back.
Additional associated with the swap include exhaust parts, uppipe, downpipe and turbo cross member. On top of that is the hours spent splicing the WRX wiring harness into your RS / L harness. For a first timer expect about 30 – 40 man hours. My time is worth about $40 an hour in my business that is an additional cost of $1200. So figure a full $4000 of real dollars as the swap cost. You may need driveline components as well.
With the swap you get a WRX engine that dynos at around 170whp. A stock EJ25 dynos at about 100whp. If you have an older Impreza your car is also lighter than current Impreza so power to weight becomes a factor as well. A 1996 – 2001 impreza only need about 150whp to equal the power to weight ratio of a bugeye WRX. I will illustrate.
A 1998 Impreza weighed about 2800 lbs ( the coupe and sedan less, the wagons more). Based on 100whp a GC style impreza has a p/w ratio of 28:1.
A 2002 WRX weighs about 3100lbs, with 170whp its p/w ratio is 18.24. To equal that p/w ratio the GC owner only needs 152hp at the wheels. This can be achieved with cams, intake, headerback and EM. New these parts would run about $2000. Do some smart shopping and your budget is closer to $1200. You also don’t have to spend the money all at once so you can use WAM (walking around money), those readers who are married know how important that can be. Keep in mind that these numbers assume the two vehicles are dyno on the SAME dyno under similar conditions. Dyno results varily widely from one dyno brand to another, one location to another and even the operator of the dyno can have and impact.
You also don’t have the down time of a swap. Parts can be bought and installed a little at a time, so the car is down for a weekend. Cams are the only parts that put you out for a week or so. The addition of heads can put the N/A owner close to WRX power levels. Coupled with the RS’s better gear ratios, a properly tuned RS can give even Stage 1 WRX’s a run for there money in most situations.
Auto-x favors the tuned N/A car. The WRX needs to spool out of every corner ( the ’06 model fixes this to some degree) unless left foot braking is well executed. The N/A motor sees good power from 2500 rpms to redline.
For the $4000 that a swap would cost a prudent N/A impreza owner should be able to reach the hi comp piston level of build, assuming the labor is DIY. This should give you at least 200hp at the wheels. Keep in mind that their only a handful of ppl attempting a build to this level and it can be time consuming. But a stock WRX needs a Stage 1 mod package to reach these levels, and at that the p/w ratio is still an issue.
Thread Starter
aka EJ20T
Joined: Apr 2007
Posts: 563
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sven i cant remeber where exactly where it was but it was in the n/a thread with forced induction and thanks for the advice slows10...i always been told i should wait so imma just wait to see wat research they come out with for the 06-07 RS then go from there
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Joined: Dec 2006
Posts: 670
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like i said, i tried the n/a route.... got wayyyy too expensive, and my main concern with my car, being a Daily Driver, is reliability.
I agree with slows10 on most of what he said, however 200whp from a gc just isn't as easy as it sounds. The money that I've spend on the car would be been WAAY better saved for an engine swap, but again my reasons for a swap are very different for yours. I NEED a new engine or atleast a complete overhaul before i put any more strain on the very old internals.
I commend you on deciding to take your time... rushing into something like this almost never ends well unless daddy is willing to foot the bill when disaster strikes.
the general consensus on intakes for our engines is to get a free-slowing panel filter, remove the snorkus from the fender, and seal the hole in the bumper with a rubber seal that SOA sells, or use duct tape (lucky your car is silver to blend in)
MY opinion is to avoid the big-name brand exhaust companies that charge an arm and a leg for a design that they copied from someone else (except for Cobb), and go to a local exhaust shop and have them bend you some pipe and weld on a free-flowing muffler for cheap. spend the money you saved on a set of headers and lightweight crank pulley.
that should run you
50 for the intake filter
0 for removing your snorkus
200-300 for exhaust
300-350 for headers
700 bucks for atleast 25whp.
I netted 24.7whp gain with those mods except no headers, but had an SAFC2(125) with dyno(100) and wb02 (100)tune. oh and i have a lightweight crank pulley from Agency Power (105)
cams will give you more power, but in most, not all cases will shift your power into a higher rpm level, meaning you will notice a loss of low power, a lag in mid-range, but a noticable gain in higher-rpm's on the order of 15hp depending on other mods..
I never thought that 800 bucks for 15whp was ever worth it, so I've avoided cams since I can't find any for cheaper than 799 new. Delta Cams offers regrinds of your stock cams, but that means you have your stock old cams being pulled out of your car, shipped out to be reground, and then shipped back to you.
alot of down-time, and I don't know that I'd trust my stock cams... but then that shows how little I actually know about cars.
I can give you advice based off of my personal experiences that you can use as a guide to get you on to the right path, but please talk to other people on other forums and get the opinions of the guys that have been building these cars for 20+ years. Use the search feature, they hate being asked this question once every 2 months and will most likely ignore a question as broad as this.
check this out...
SUBARU LEGACY INTERNATIONAL CLUB -- View Forum - Swaps & Conversions thats all about swaps and conversions
SUBARU LEGACY INTERNATIONAL CLUB -- View Forum - Engine & Drivetrain
and thats for your general engine questions, performance or maintainance
I agree with slows10 on most of what he said, however 200whp from a gc just isn't as easy as it sounds. The money that I've spend on the car would be been WAAY better saved for an engine swap, but again my reasons for a swap are very different for yours. I NEED a new engine or atleast a complete overhaul before i put any more strain on the very old internals.
I commend you on deciding to take your time... rushing into something like this almost never ends well unless daddy is willing to foot the bill when disaster strikes.
the general consensus on intakes for our engines is to get a free-slowing panel filter, remove the snorkus from the fender, and seal the hole in the bumper with a rubber seal that SOA sells, or use duct tape (lucky your car is silver to blend in)
MY opinion is to avoid the big-name brand exhaust companies that charge an arm and a leg for a design that they copied from someone else (except for Cobb), and go to a local exhaust shop and have them bend you some pipe and weld on a free-flowing muffler for cheap. spend the money you saved on a set of headers and lightweight crank pulley.
that should run you
50 for the intake filter
0 for removing your snorkus
200-300 for exhaust
300-350 for headers
700 bucks for atleast 25whp.
I netted 24.7whp gain with those mods except no headers, but had an SAFC2(125) with dyno(100) and wb02 (100)tune. oh and i have a lightweight crank pulley from Agency Power (105)
cams will give you more power, but in most, not all cases will shift your power into a higher rpm level, meaning you will notice a loss of low power, a lag in mid-range, but a noticable gain in higher-rpm's on the order of 15hp depending on other mods..
I never thought that 800 bucks for 15whp was ever worth it, so I've avoided cams since I can't find any for cheaper than 799 new. Delta Cams offers regrinds of your stock cams, but that means you have your stock old cams being pulled out of your car, shipped out to be reground, and then shipped back to you.
alot of down-time, and I don't know that I'd trust my stock cams... but then that shows how little I actually know about cars.
I can give you advice based off of my personal experiences that you can use as a guide to get you on to the right path, but please talk to other people on other forums and get the opinions of the guys that have been building these cars for 20+ years. Use the search feature, they hate being asked this question once every 2 months and will most likely ignore a question as broad as this.
check this out...
SUBARU LEGACY INTERNATIONAL CLUB -- View Forum - Swaps & Conversions thats all about swaps and conversions
SUBARU LEGACY INTERNATIONAL CLUB -- View Forum - Engine & Drivetrain
and thats for your general engine questions, performance or maintainance
