|
|
|
|
Thread Tools | Display Modes |
01-17-2007, 03:10 PM | #1 |
Scooby Specialist
Member#: 49978
Join Date: Dec 2003
Chapter/Region:
NESIC
Location: Shrewsbury, MA
Vehicle:2002 WRX w/ JDM STi 6spd, EJ255, VF39 & EWG |
Is my WGDC affecting max boost? EWG VF39 2.5L 02 WRX
Here is my problem: I had a Bosal twin dump DP mated to the stock 3rd cat from an 02 WRX. At 20psi with all the below mods (before HKS DP) the car made 220whp and 240wtq. 20psi was the max that the turbo could make, and the shop suggested backpressure was an issue. The wastegate was fully shut, and yet the turbo could make no more boost. They attributed this to the cat creating excessive backpressure.
About a week ago I swapped the Bosal/3rd cat combo in favor of an HKS DP. Now I am only seeing 11psi at WOT in 3rd gear, and 12psi at WOT in 5th (100mph or about 4100-4200RPM). So here are my questions: 1. Could the issue of backpressure have forced my tuner to give uncharacteristic WGDC values that are now preventing me from making more boost? 2. If not, what could be preventing me from making boost? Leaks might be possible, but it was immediately after the downpipe swap and I am sure nothing was bumped. 3. Would using an MBC in place of the stock BCS allow me to figure out if I can make more boost, and is this a reasonable solution in the short run? I know that info is needed to answer my questions, so here's the mod list: USDM Legacy GT EJ255 engine swap (full longblock minus intake manifold and throttle body, no AVCS hooked up) SSAC top mount intercooler EcuTeK flash on 2002 WRX ECU Seimens 660cc injectors Walbro 255lph fuel pump UR EWG uppipe TiAL 38mm WG VF39 with welded flapper HKS heat-coated DP Stock 2005 WRX catback Something else I feel should be mentioned. At 11psi in second gear, the butt dyno feels the same power as it used to feel at 18-19psi. My guess is that the tune had headroom and now the car is making some more power, but I am not sure how much more.
* Registered users of the site do not see these ads.
|
01-17-2007, 10:13 PM | #2 |
Scooby Specialist
Member#: 49978
Join Date: Dec 2003
Chapter/Region:
NESIC
Location: Shrewsbury, MA
Vehicle:2002 WRX w/ JDM STi 6spd, EJ255, VF39 & EWG |
I will answer myself as #3 was performed tonight and we reached 20psi without issue. This should be fine in the short run, we didn't set it close to 20 psi, rather around the 14psi mark. Also, it's 18 degrees F out tonight, so it should be a tad less in warmer weather.
My assumption in #1 was most likely correct. By eliminating the use of the stock BCS, we cured the inability to make boost. Therefore, this is a tuning issue, not a mechanical one. We don't need to address #2. It's alright that no one responded and made a suggestion, I just hope that this will help someone in the future who may run into the same or a similar problem. |
01-18-2007, 08:40 AM | #3 | |
Scooby Specialist
Member#: 44422
Join Date: Sep 2003
Chapter/Region:
SWIC
Location: Gilbert, AZ
Vehicle:2009 G8 GT Cammed, sprayed, stalled |
Quote:
Also, are you using a stock, unmodded BPV? If so, that could also be part of the issue. THey are known to not hold boost above 18-20 psi. They can be modded for $0.16 (search thread) and hold much more boost. |
|
01-18-2007, 12:02 PM | #4 | |
Scooby Specialist
Member#: 49978
Join Date: Dec 2003
Chapter/Region:
NESIC
Location: Shrewsbury, MA
Vehicle:2002 WRX w/ JDM STi 6spd, EJ255, VF39 & EWG |
Quote:
Many people who go to an EWG setup do not utilize the stock BCS, instead they use the GM, Perrin, or Prodrive, or a better EBC like the AVC-R. We are using both ports on the MBC as TiAL suggests in the diagram on their website. Here is how it's set up: The only thing we did was eliminate the vent coming from the top port of the WG to the side port of the MBC. Putting a T in there would release too much air, so I will set it up that way when the GM BCS goes in. |
|
01-18-2007, 12:26 PM | #5 |
Scooby Specialist
Member#: 44422
Join Date: Sep 2003
Chapter/Region:
SWIC
Location: Gilbert, AZ
Vehicle:2009 G8 GT Cammed, sprayed, stalled |
Where is the discharge from your EWG tied in? Or does it dump to atmosphere?
|
01-18-2007, 12:38 PM | #6 |
Scooby Specialist
Member#: 49978
Join Date: Dec 2003
Chapter/Region:
NESIC
Location: Shrewsbury, MA
Vehicle:2002 WRX w/ JDM STi 6spd, EJ255, VF39 & EWG |
The EWG setup is VTA, I love the sound You shoulda seen the smile on my friend's face when telling his brother how awesome it was. It might n ot be super pratical, but it keeps me from mashing the go pedal quite a bit.
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Max Boost on vf39 | S0N | Newbies & FAQs | 5 | 07-16-2007 07:02 AM |
Map Question vf39 2.5L wrx | Mooneyes13 | AccessPort | 2 | 07-14-2007 11:06 AM |
02 WRX, 2.5L STI/wrx heads, GT30R, 93 oct-344whp/329wtq, c16-433whp/398wtq | Astacun1 | Proven Power Bragging | 31 | 12-29-2005 11:16 AM |
max boost with vf39 | stealthblksti | Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) | 3 | 11-22-2005 01:24 AM |
is there a 02 2.5l turbo wrx??? | rmontheweb | General Community | 4 | 11-17-2005 12:21 AM |