Subaru WRX Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Ok, so this is the first time I have made mods to my wrx, I will give you the run down of parts and the issue as I understand it. 2017 WRX with turbo back exhaust, Perrin FMIC kit, a BOV, misamota race intake, and a Radiator cover, that forces air into the intake and Cobb accessport. When ordering the parts the sales person told me I should be good to run stage 2 bf plus, so on my accessport I loaded stage 2 bf 93 304. The car cranked up fine, no check engine lights, I checked to make sure I had no air leaks and no unhooked wire harness. To the car out for a test drive , sounds great seems to have more power. As I let off the gas the car shuts off. I pull into a parking lot, check my tune to make sure I have the map that I was told, check for codes which there was none. Cranked the car and drove it back home. It seemed like as long as I was on the gas the car was fine. The second I let off to stop it seemed like the rpms would just drop to 0 and the car would shut off. When i got home i tested this, cranked it up and let it Idle, reved the gas and let out it shut off. Can you guys offer any pointer for me to look at?
 

·
Super Moderator
Joined
·
11,417 Posts
Ok, so this is the first time I have made mods to my wrx, I will give you the run down of parts and the issue as I understand it. 2017 WRX with turbo back exhaust, Perrin FMIC kit, a BOV, misamota race intake, and a Radiator cover, that forces air into the intake and Cobb accessport. When ordering the parts the sales person told me I should be good to run stage 2 bf plus, so on my accessport I loaded stage 2 bf 93 304. The car cranked up fine, no check engine lights, I checked to make sure I had no air leaks and no unhooked wire harness. To the car out for a test drive , sounds great seems to have more power. As I let off the gas the car shuts off. I pull into a parking lot, check my tune to make sure I have the map that I was told, check for codes which there was none. Cranked the car and drove it back home. It seemed like as long as I was on the gas the car was fine. The second I let off to stop it seemed like the rpms would just drop to 0 and the car would shut off. When i got home i tested this, cranked it up and let it Idle, reved the gas and let out it shut off. Can you guys offer any pointer for me to look at?
Cobb offers no off the shelf tune that supports what you have on that car.

You need to removed the blow off valve and replace the factory bypass valve, the engine management can not support vent to atmosphere. You then need to go find a reputable tuner in your area and have them tune the car.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #3 ·
Cobb offers no off the shelf tune that supports what you have on that car.

You need to removed the blow off valve and replace the factory bypass valve, the engine management can not support vent to atmosphere. You then need to go find a reputable tuner in your area and have them tune the car.
I am assuming then I will be about to run my BOV after pro tune?
 

·
Super Moderator
Joined
·
11,417 Posts
I am assuming then I will be about to run my BOV after pro tune?
No, you can sell it to recoup some of the cost of the pro tune.

Read the big blow off valve thread. Your car in no way shape or form with the factory ECU supports blow off valves. Only bypass or fully recirculating "blow off" valves (at that point is a bypass valve).

To support one you'll need new engine management capable of supporting speed density over mass airflow.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
No, you can sell it to recoup some of the cost of the pro tune.

Read the big blow off valve thread. Your car in no way shape or form with the factory ECU supports blow off valves. Only bypass or fully recirculating "blow off" valves (at that point is a bypass valve).

To support one you'll need new engine management capable of supporting speed density over mass airflow.
So I just looked up the BOV thread, and please excuse my ignorance , but from what I was reading I have the GFB bov that you can adjust, and I think it can go to 50/50. I was reading the paper work that came with it, and said it might need to be adjusted which I never thought that would cause rich conditions so that info is good to know. But let's talk about the ECU, and this will be where i know very little, but when you said factory ecu will not support it, please correct me if I am wrong but I thought that was the whole point of the accessport was to re-map the ecu to adjust for what I put on it?
 

·
Super Moderator
Joined
·
11,417 Posts
Subarus engine management strategy won't support it. No matter how it's tuned. A maf based system can not account for it like a speed density one will.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
Ok so here is my update, I have adjusted the GFB BOV to somewhere around 50/50, it's hard to tell exactly where it is set to being that you can only get to it from under the car and by feel. 2nd I adjusted the preload on the bov so the rpms do not drop out, I tested the car in the garage and it seemed to be fairly good. Test drive: 1st gear feels good, 2nd gear I noticed when I got around 5k-7k felt rough, same in 3rd gears as well. The over all car does not feel any faster, and I ran a 0-60 pull on the car and because of the rough studder at top end the car ran slower. I also noticed my peak boost dropped, stock with cat back and stage 1 I had 21psi peak, now the highest I got was 17psi. Is this from going from stock TMIC to FMIC? Longer piping equaling psi drop? Or signs i have a leak?
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #8 ·
Update, and new question: After tune the car runs great and I'm getting around 310hp and 345tq. My question now is what is the next thing to do after the bolt ons? Bigger tuber, engine work? If so what?
 
1 - 8 of 8 Posts
Top