so im getting a wrx, can someone help me out with a little info - Page 2 - PbNation
Find fields & stores near you!
Find fields and stores
Zipcode
PbNation News
PbNation News
Community Focus
Community Focus

 
Archived Thread - Cannot Edit  
Old 07-30-2004, 02:02 PM #22
golfer
IMAREALTUNERLOL
 
golfer's Avatar
 
Join Date: Apr 2001
Location: Eau Claire, WI
 has been a member for 10 years
Primary reason of a BOV is to reduce strain on the compressor turbine wheel due to compressor surge. Between shifts, or sudden throttle lift-off, the turbine is still spinning very fast (but slowing) and pumping air at the closed throttle plate, as well as placing strain on the intercooler, hoses and fittings. A BOV keeps air from flowing backwards over the compressor wheel, allowing the turbine to continue spinning freely. When back on the throttle, boost pressure quickly rises again with little lag.

I win.
__________________
You wish you were this cool...
golfer is offline  
Old Sponsored Links Remove Advertisement
Advertisement
Old 07-30-2004, 03:11 PM #23
Frenchtoastdude
Ohhhh Yeeeaaaa
 
Frenchtoastdude's Avatar
 
Join Date: Oct 2001
Location: Oregon
 has been a member for 10 years
damn thanks for all the info, its not going to be tough to pass DEQ with a catback is it? and I may hold off on the cold air for a while, Im still deciding on the BOV since im getting good and bad opinions.
__________________
Oregon State University
College World Series Champions 2006, 2007
Frenchtoastdude is offline  
Old 07-30-2004, 04:40 PM #24
pntballfreak
 
 
Join Date: Mar 2002
Location: orange county/Socal
 has been a member for 10 years
So much misinformation...

1st off...try going to Nasioc and do some research on all the options out there.

IMO, the 1st mod you should do is engine management...UTEC, Accessport, ECUtek, etc. I went with the Accessport just cuz it's pretty user friendly. I'm running a Stg. 1, 91oct. map and dynoed at 200whp. I didn't do a initial run stock, so I'm not sure how much I gained. However, stock WRX's were dynoing ~180whp all day.

Next up would be opening up the exhaust...uppipe and turboback. There are so many choices out there...just depends on your budget. I have a gutted stock uppipe, Stromung downpipe and HKS catback sitting in the garage...all totalled to about $700. I'm actually gonna sell the HKS and get something more stealthy. An intake might cause problems with the MAF sensor and you might run a little lean depending on the intake. I suggest saving the money on the exhaust parts.

BOV's...personally, unless your running crazy amounts of boost, I wouldn't spend $150+ for sound...there is no performance gain with an aftermarket BOV on a stock turbo. The stock bypass/blow-off (whatever you want to call it) can hold up to 21psi. It's recirculating which is why you don't hear the typical "pssshhhh" sound. Running a 100% atmospheric BOV will make you run rich. GFB and Worx Tuning both make BOV's which are adjustable...meaning that you can adjust how much you can make atmospheric/recirculating...so you can get the sound and still run okay. I'm currently running a GFB Hybrid BOV...but am going back to stock. I was lucky and bought it used for $75... I ran it at 100% atmospheric and had stumbling problems. It's at 50/50 right now and have none of the stumbling problems. BUT, now I'm having a problem with compressor surge. The sound was fun for a while, but I'm worried about the longevity of the turbo.

Basically, what I would recommend is engine management, first, and exhaust (turboback) next. That's good for ~225-230whp.

Last edited by pntballfreak : 07-30-2004 at 04:44 PM.
pntballfreak is offline  
Old 07-30-2004, 05:57 PM #25
hiaseas
Tool
 
hiaseas's Avatar
 
Join Date: Feb 2001
Location: Long Island, NY
 has been a member for 10 years
I have an 04 WRX, I figure my first mod will be getting new wheels and tires because the stock tires are horrible.

Whats the nicest/deepest sounding exhaust out there for the WRX?
hiaseas is offline  
Old 07-30-2004, 06:06 PM #26
Frenchtoastdude
Ohhhh Yeeeaaaa
 
Frenchtoastdude's Avatar
 
Join Date: Oct 2001
Location: Oregon
 has been a member for 10 years
ya can I get a few opinions on which exhaust to get and also can someone explain running rich, I have a 4runner right now which im selling for 10 grand and I had a civic before, I didnt really care about performance, im new to all this.
__________________
Oregon State University
College World Series Champions 2006, 2007
Frenchtoastdude is offline  
Old 07-30-2004, 07:05 PM #27
pntballfreak
 
 
Join Date: Mar 2002
Location: orange county/Socal
 has been a member for 10 years
Put it simply...it's when there's more fuel versus air in the combustion chamber.

Exhaust...depends on what you want. If you want something relatively quiet, there's the Greddy Evo, Borla Hush, or the Prodrive axleback. Then you have the N1/canister style like the HKS Hi-power, Blitz Nurspec, Expilir (sp?), etc. Personally, I want something fairly quiet and looks stock, so I think I'm gonna go with the Borla Hush.
pntballfreak is offline  
Old 07-30-2004, 10:43 PM #28
ok fine
Traces of Day
 
Join Date: Aug 2003
 has been a member for 10 years
Thinking about putting an intake, blow off valve, or boost controller on your WRX? Before posting about it, check this out cuz the WRX isn't every other car out there and a lot of the 'normal' mods don't work the same way on it.

Intakes: The Mass Air Flow sensor (measures the amount of air going into the engine) on the WRX is very sensitive. It is designed and calibrated for the diameter of the stock intake piping, the way it's mounted on the piping, and the distance it is from the turbo inlet. Many of the aftermarket intakes for the WRX did not take this into consideration. Some of them have diameters that differ enough from stock to cause serious problems.

Even the intakes designed properly for use on the WRX rarely cause gains in power. It is generally accepted that the stock intake doesn't start to become a restriction until 300 hp and I personally think it's higher than that. High enough that with the stock turbo it's impossible to make enough power for the intake to become a restriction. With the silencer removed, the intake is pretty darn similar to an open, short-ram style intake, and if you have a properly designed aftermarket intake the tubing is the exact same diameter as stock anyway... so where's the restriction coming from? Many intakes lean out the air/fuel mixture, which can be good for a couple ponies on a car with no tuning. Once tuned though for either the stocker or an aftermarket one, I don't think a difference would be seen.

The intake most well-known to cause problems is the AEM (short ram or CAI, doesn't matter). Not only does it cause the MAF reading to be off, but it causes irradic readings that make it IMPOSSIBLE to tune for. No tuner (Vishnu, Cobb, TurboXS, etc) will even touch a car with an AEM intake on it, period. Best bet? Put the money somewhere beneficial!

BOV's: The stock valve is a recirculation valve. All of the air it bypasses gets sent right back into the intake and then into the engine. The thing is that it gets sent back into the intake after the MAF sensor so it's not actually measured. The ECU just assumes that it's getting all of that air back into the engine. So when you swap on an aftermarket BOV that vents all of that air into the atmosphere, obviously none of it's going back. However, the ECU doesn't know this so it's still injecting fuel for all of that air. This causes a brief rich condition every time the BOV does its thing. It's not really a big deal, but these are the side effects:

-- slight hesitation while the car burns off that extra fuel. Most people can't even feel this and it depends a lot on your driving style. Certain BOV's are worse than others in this regard, but even the worst one isn't that bad so if you really, really need the psssshh sound you may want to just bit the bullet on this one.
-- Afterfiring. This one you're going to have if you get an atmospheric valve. That extra fuel is going to burn in your exhaust, and it will cause a popping sound. If you're catless, it's gonna be fairly loud and might get annoying after a while. Some people like it, I found it annoying. If you have cats you may not really notice it, but that means the cats are destroying all of that extra fuel and are going to break down and need replacement sooner than they would otherwise.
-- Idle problems. This I don't really attribute with a general BOV problem, it's really a problem with a poorly-tuned BOV. However, lots and lots of people have problems with the car's idle when they put an aftermarket valve on so it's gotta be mentioned. Obviously if your car doesn't idle right it's a big problem.

Bottom line is that the stock valve is, by far, the best. The car runs and performs the best with it. It is good up to 18 to 20 psi. If you're running less, you DO NOT need to replace it. Anybody that tells you a BOV is a performance mod on the WRX is wrong. 50/50 and adjustable valves cause less problems than totally atmospheric ones, but the stocker still wins out for performance. It's even semi-noisy if you remove the intake silencer and pop a nicer panel filter like an ITG in there. I can hear mine echo off walls and stuff...

Boost Controllers: Manual or electronic, both can cause serious problems. With the stock boost control system, the car only gives you full boost at full throttle (which is over like 76% or something... ish). With an aftermarket boost controller, you'll get full boost whenever the turbo is capable of it, which includes partial throttle times from like 15% throttle on up. You do a lot of daily driving and highway driving in this range. The problem is with the ECU once again. At partial throttle the car usually sees 7 to 10 psi, or about wastegate pressure. It injects only enough fuel for 7-10 psi. When you pop a boost controller on there it just assumes you're still getting 7-10 psi, but you're getting full boost, which is probably 14.5 to 16.5 depending on where you set it. So you've got the fuel for 7-10 psi but 14.5-16.5 psi of boost! This causes an extremely lean condition because of all that extra air without any extra fuel, EGT's (exhaust gas temperatures) shoot through the roof, and soon a piston melts.

There are a couple ways around this problem. One is to drive your car at under 10% throttle or at full throttle all the time and never drive anywhere in-between. There are plenty of people who do this, but that seems like a huge and annoying sacrifice. You could get a Vishnu EMI adapter (or similar product), which tricks the ECU and makes it safe to run full boost at partial throttle, but it makes the car a bit choppy as the transition between closed and open loop operation is not well defined. Or you could get a very fancy and expensive electronic boost controller that has throttle position input. Basically you tell it not to step in unless your throttle position is over 80% or whatever number you choose. However, these are like $600+++

Now here's the kicker. For under $400 you can have your ECU reflashed. This not only raises boost SAFELY but it changes your ignition timing and fuel curves to fully take advantage of it. Less money, total safety, and more HP because of the additional tuning. Boost isn't everything. Tuning for that boost will truly make your car fly. If you need solid proof: my friend dyno'd his car with identical mods to mine, except he had a boost controller set at 16.5 psi on high setting and I have Cobb Stage 2 tuning. He put down 219 whp on the dyno, and I put down 237. I made 18 more hp at the wheels with slightly less boost and I'm not going to melt a piston like he did after about 5 months of running the boost controller. And his had two settings... 90% of the time he was running it at 14.5 psi, which is stock boost. You don't have to crank it to melt a piston. On top of that, my curves were smoother and my A/F ratio was much, much better controlled.

Turbo Timers: They're cool but you don't technically need it on a WRX. On the rex the turbo is lubricated by the oil and cooled by the coolant. On a lot of cars the oil does both jobs, which is why you leave your engine running afterwards--to keep the oil circulating. That could apply with coolant also, but Subaru actually did something cool here:

You know that coolant resevoir tank that's above the turbo up on the left (passenger) side of the engine? Well the coolant entry to the turbo is below it, and the coolant outlet comes off of the top of it and goes right to that resevoir. Basically, even after the engine is off, if the turbo is hot it will continue to circulate the coolant because the coolant inside of the turbo gets heated above the temp of the rest of the coolant and rises up into that resevoir. When that happens cooler coolant from below the turbo gets sucked up into it and it keeps cycling until the difference in the temperature of the turbo and the coolant isn't very big.

If you take a hard drive and get the turbo really hot and don't drive gently for a couple minutes before parking just chill in the car for a minute and let it idle down. Never a bad idea to let it idle for a minute so some stuff can cool down and things can settle and whatnot, but 99% of the time there's no reason for the car to idle at all.

Not getting one will save you $120+... get intercooler hoses or put it towards a downpipe or something instead

BTW -- MisterX reminded me that installing a turbo timer will very likely cause your dealer to void your engine warranty if you go in with any sort of engine-related problem, or if they see it in your car while you're at the dealership for something else. For a mod like this, it's definitely not worth the risk.

__________________________________________________ ________________________________

Now just so you know, I've had an intake, I've tried three BOV's, have a turbo timer and I've run an expensive electronic boost controller in conjunction with a Vishnu EMI adapter for safety. The short ram intake I had was one of the properly designed ones. Going back and forth from that to the stocker I was able to tell no difference. Actually, at night when it was really, really cold I felt slightly better pull with the stocker pulling cold air out of the fender vs. the short ram taking warm air from the engine compartment. Normally this doesn't make a difference because the turbo heats up the air anyway, but when it was super cold out I could tell. I liked the sound of the BOV's of course but they were all obnoxious and it ran sooooo much better with the stocker I always went back to stock. I sold the boost controller and EMI adapter for much more than my current tuning cost. Not only does the car make a whole lot more power with the tuning, but it's smooooooth smooooooth smooooooth. It feels sooooo good. You can't touch that with a boost controller.

So there are the facts. Choose your mods wisely.

POSTED BY:EJ20Legacy
of wrxfanatics.com
__________________
Traces of Day
ok fine is offline  
 




Posting Rules
Forum Jump