[ColeWRX]

Hey guys, I've got a 2003 Subaru Impreza WRX. The only modifications that I have made so far are a Cobb short ram intake, deleted resonator, and deleted muffler. I'm just looking to see a rough idea of how much horsepower I will gain with the following mods:

Walbro 255lph fuel pump
DW 565cc Injectors
GFB Hybrid BOV
Cobb ap v3

Not looking for anything serious, just looking for some rough estimates. Obviously I will have it tuned for the modifications. Thanks in advance!

 

[MainFrame]

Probably somewhere around 200whp.. the stock downpipe (and turbo) will be a big restriction.

 

[zax]

Why would you not install a downpipe?

Those fueling mods are not necessary for stage 1 nor will gain any additional power.

190whp or whereabouts.

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[ColeWRX]

Sorry, should have clarified. I AM installing a down pipe, just not right away. vf39 turbo is coming soon as well.

 

[SD_GR]

I'd do it all at once.

 

[ColeWRX]

Sorry to pest, but say I did this all at once, tune and everything. What kind of numbers would I be looking at then?

 

[zax]

Sorry to pest, but say I did this all at once, tune and everything. What kind of numbers would I be looking at then?

200-230whp.

Numbers mean absolutely nothing. What are you doing with the car i.e. sanctioned racing, personal fun, etc?

 

[ColeWRX]

Thanks man. And to be honest, I just want to tinker right now. Not looking to race or anything. Maybe a few pulls here and there, I just want a little pep under the hood at the moment. Really excited to start modifying. How much boost should I run on stock internals? I thought I read somewhere that I shouldn't exceed 18lbs.

 

[zax]

Thanks man. And to be honest, I just want to tinker right now. Not looking to race or anything. Maybe a few pulls here and there, I just want a little pep under the hood at the moment. Really excited to start modifying. How much boost should I run on stock internals? I thought I read somewhere that I shouldn't exceed 18lbs.

You shouldn't be focusing on boost, focus on the mod paths.

Next step should be a larger TMIC, TGV deletes, and then you can go with a larger turbo.

Make sure the braking and handling matches the power... bugeyes lacked quite a bit in the cornering/braking department.

 

[MainFrame]

How much boost should I run on stock internals? I thought I read somewhere that I shouldn't exceed 18lbs.

That depends entirely on the parts used and how the tune is set up. A good tuner will find the optimal boost for the car during the tuning process.

 

[AltairRules]

Also don't get a bov of any sorts unless you want to go down the path I did to run a bov without negatively affecting the car. Just stick with the stock bpv. FYI it costed me about $200 in work by my tuner to go the bov route and that's just sensors and install

 

[ColeWRX]

Oh awesome! So if you were to point me in a direction from first to last, what order should I install the parts?

 

[ColeWRX]

I was just gonna install a GFB hybrid, that way it doesn't vent to the atmosphere. That wouldn't hurt right?

 

[AltairRules]

As long as it's 100% recirc but I'd just save your money and buy a different part that could improve performance. Every knowledgeable person I've talked to including my tuner, said to stay with the stock bpv unless there's a legitimate reason to replace it because the stock ones are really good.

 

[AltairRules]

I'd actually get a catless up pipe instead of the hybrid bov so you can avoid the fate that I had. My pre cat grenaded and took out my turbo. So, a new catless up pipe, catless DP, 16g turbo, STi dark blues, walbro fuel pump and a tune later......it was driving again. Lol all of which was cheaper than oem parts

 

[ColeWRX]

Awesome, thanks man!

 

[MainFrame]

Oh awesome! So if you were to point me in a direction from first to last, what order should I install the parts?

First, how many miles does the engine have on it, and have you done a compression or leakdown test recently?



I if the entire car is 100% in working order, good condition, all maintenance up to date, etc. Then I would install the vf39, uppipe and downpipe, Walbro 255, a better TMIC, a 3-port EBCS, and plumb the compressor outlet on the turbo directly to the wastegate actuator. Then I would limp, or have it towed to the tuner.. once there I would install ID1000s, plumb the EBCS back in, and have the car protuned.

I would also put a muffler back on the exhaust.. something non obnoxious.

 

[ColeWRX]

Okay awesome, and yeah it's quite ignorant at the moment. So the engine can handle the vf39 with no supporting mods besides a tune? Or install the turbo with the up pipe and dp..

And no, compression test has not been done. It will be before I upgrade the turbo

 

[AltairRules]

First, how many miles does the engine have on it, and have you done a compression or leakdown test recently?



I if the entire car is 100% in working order, good condition, all maintenance up to date, etc. Then I would install the vf39, uppipe and downpipe, Walbro 255, a better TMIC, a 3-port EBCS, and plumb the compressor outlet on the turbo directly to the wastegate actuator. Then I would limp, or have it towed to the tuner.. once there I would install ID1000s, plumb the EBCS back in, and have the car protuned.

I would also put a muffler back on the exhaust.. something non obnoxious.

I prefer subies to have
View attachment 272674
Lol

And also some tuners will send a limp map you can install to get you there to the shop if you've already paid for the dyno session

 

[XJman]

I would get the leak down test done well before you decide to start dumping money into it. If you've already got thousands of dollars in parts laying around and have to replace a short block for thousands you may not have the money for repairs.

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