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Cobb Accessport v3 loss of power? 04 wrx

12K views 16 replies 10 participants last post by  tjkuip0 
#1 ·
Hey guys. I joined the forums to see if you guys have any suggestions or knowledge about this problem. I have a 2004 Subaru impreza wrx. I got it completely stock and the mods up to now are:
SRS down pipe
SRS manifold
SRS up pipe
HKS bov
K&N Intake filter
full 3" Straight pipe down to a magnaflow muffler.
I was running a steady 14.4-14.5 quarter mile on the track (without the magnaflow straight pipe and intake filter)
I got my bolt ons done and decided to purchase a cobb accessport v3 brand new. I installed the stage 2 93 octane base map thinking that my car would push in the high 13s and run a little better. At first it seemed smoother to drive but I went to the track later that night I was running 15.4 to 15.8s? I gained a second. I know it takes a bit for your car to get used to a base map but it's been a week and it seems to be much slower and sluggish. From a launch it seems to be strong but when I shift into second it seems to just drop really low (4000-4500 rpms) and it just seems like it drops to low of rpms and then tries to catch back up. So I've narrowed it down to a either the magnaflow muffler, or the cobb. Maybe I just need a pro tune but it just seems a little odd to lose a full second. My launches were fine too, didn't miss any gears, clutch didn't seem to be slipping or my motor didn't seem to lose any power or compression? any help would be greatly appreciated.
 
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#2 ·
Well for starters, your muffler didn't cause you a second, and surely your AP didn't.

When did you put that BOV on?
This may be a touch OT, but that is probably one of the worst on the market. Only second to a $10 eBay valve.
Your map is expecting to see that air come back through the intake which is no longer happening.
So I'd start with replacing that with a Cobb XLE or something close to that.
A BPV is a must.

Others will chime in soon on other routes you should go with your car.
 
#3 ·
What are you boosting up to? Maybe your HKS BOV is leaking and either is not able to handle the boost or needs to be adjusted. I have a 05 WRX wagon with the stage 2 93 Octane and boost a steady 16.5-16.75. I have pretty much the same mods as you although I don't have the manifold or the HKS BOV, mine are both stock. So my first guess would be the BOV.

Also is the HKS recirculating or is it venting to the atmosphere?
 
#4 ·
You shouldn't be running that map because it was not made for your mods.

1. Catless downpipe. The Cobb map was made for a catted downpipe.
2. Upgraded manifold. This increases the exhaust flow even more especially when combined with a Catless downpipe. Not compatible with this map.
3. Hks bov. This bov is doing nothing but adding more problems to the equation. A bov/bpv does nothing when at full throttle unless its leaking. The HKS is one of the worst for leaking. The system was designed for the air to be rerouted back into the intake. This combats compressor surge and also helps keep the turbo spooling between shifts. The HKS vents the air into the atmosphere instead of back into the intake. The ecu has already measured this air and is calculating fuel and such for it when it is rerouted like it is supposed to be. The Cobb map wasn't made with a bov in mind.

You should probably get a stock bpv or a good quality aftermarket one and a protune if you want everything right. I bet this will get your timeslips back where they were or better.
 
#5 ·
1. What is your DAM? Have you done any logging at all?

2. Take the valve off. Put the stock one back on. Do your runs again.

It could also be that your car is rejecting the OTS maps. These are generic base maps and some cars take better than others to them. These should never be pushed into motorsports use as they are not safe for it. Dozens of people have lost motors motors doing this.
 
#6 ·
I know all cars react to the OTS Maps differently but my exhaust system is completely Cat-less and I see no issues. Although I don't have the manifold which does change things.

Is the manifold an equal or unequal length header?

I would personally start with changing back to the stock BPV and see how things go. If you see improvement but not what you are looking for then go back to the stock manifold as well and see how things go.

Log a pull and upload it for us to view. You can also send it to Cobb and they can probably help you out.
 
#7 ·
This is the first time I've ever even heard of it being the bov. It's a $300 bov and its a HKS, so I am almost certain it's not the bov. My best was a 14.3 on the track with a shitty launch. I was running the 14.3 with the HKS bov and I got the car with the bov on before I did anything at all it had it. When I hit the 14.3 I was running it with the bov, manifold, up pipe, and down pipe. I didn't have the intake, cobb, or 3" exhaust. Oh, and btw I was running it with a down pipe to the stock resonator, to nothing. It has no muffler (the guy took it off when I bought the car) and when I put the cobb and 3" exhaust to a magnaflow thats when I gained a full second. So it's either the cobb accessport or the magnaflow. Alot of people say the magnaflow but in my opinion, before I put the cobb on it felt like it was running hard and strong and after the cobb it felt slower when I got on it. It just seems like when I redline in first and shift into second the rpms drop way to low and try to catch up.
 
#10 ·
I would think the OTS map is causing the issue. It is a generic map not designed for your specific car. Every car is different, with that being said the map may not have all parts of the tune zeroed in on what your car may need or want causing performance to be taken away. As brafal stated those maps were not designed to drive hard on. Even if they were I can't say I'd trust them for long lengths of time driving the car hard being that they are generic. I would highly suggest/recommend getting a protune/etune before driving the car hard at the track again. Do yourself and your car a favor. I would also get rid of the BOV and either go back stock BPV or go to a nice aftermarket BPV, either Cobb or Forge.
 
#11 ·
@Chri,

When you install the Cobb Accessport the first thing it does is download your existing map and reflashes your ECU with their OTS map. that may be why you are feeling a huge loss of power and a lost second. To resolve the issue you might be able to just uninstall the accessport ( turn the key to on, go to the bottom of the menu and choose uninstall) it should revert to whatever map was on the car when you first installed it. That might help : )

Either way Please have a professional tune you car. Im not going to bash on your HKS or question your magniflow exhaust but please have a pro tune your car. Cobb cannot create an OTS map for every possible configuration of intake/exhaust and you have aftermarket headers and an "offroad only" catless down pipe. For your build a pro tuner will be able to unlock some real power and it is possible that one of your parts may not be handling the power properly.

the only thing I would change is the BOV for a BPV, your parts list did not suggest an aftermarket computer to handle the loss in airflow after an atmospheric pressure dump. a bypass valve will prevent any undue rich condition and will help you keep a more even power curve between shifts. Losing power to a rich condition between shifts could definitly turn a 14 second car into a 15 second car. especially with 3 shifts.

I would take it t a tuner and have it dyno tuned then track it a gain and let us know how your 14 sec car is running.
 
#13 ·
I appreciate the inputs and help. I'll double check the bov but if I was running low 14s with the hks bov and put a cobb on and now gained a second. It's most likely not the bov. In my poinion of driving the car it seems to be the map. Maybe I just need a pro tune and it should resove these problems. Alot of people are saying it's the muffler but it's 3" straight piped to a 3" inlet and outlet magnaflow pan. It's kinda quiet unless you get on it but I'm not sure it's the muffler either. Probably the cobb. I was thinking of just uninstalling the cobb and then running it on the stock map and see if I gain any time. That will prove that it is the cobb.
 
#15 ·
I said it in my previous post when you install the Access-Port and OTS map it removes the stock map and adds the cobb OTS map of your choice. Please follow the uninstall process for your access-port and have your favorite tuner make a map for you. you can download it onto your accessport and you will be able to use the accessport properly. Otherwise you are using a cobb OTS map with the wrong supporting mods.
 
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