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Discussion Starter · #1 ·
Hello all I have a question that I cant find the exact answer I am looking for. I have a 2007 sti currently modded to 345whp. Im looking to take it to the next power level with e85 hoping to reach 450whp. Currently I am running a 73mm kstech and have already gone through the state ref process here in Ca and dont want to again. My goal is to make the engine bay as stock looking as possible and why I run a tmic with a blouch 2.5xtr 10cm w/2.5 inlet. I need to ditch the intake because of not being CARB approved. I am thinking of running the stock airbox with a knn drop in filter. Do you guys think the stock airbox will support the power I am looking for? I have read posts of folks saying it will support 400+ but i have not seen the proof so lets talk about it. I ordered a knn typhoon and compared the filter area to the stock filter and my kstech filter which i dont see a significant difference in filter area so im going to return it. Also I am aware the MAF will max out and why im going speed density so it will not be an issue anymore. Thoughts and suggestions are welcomed thanks.
 

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I remember around 2012ish there was someone running a stealthy TMIC with a blouch dom and a JDM STi air intake with drop in filter (MAF housing was 70mm) on a 2007 SWP STi. Lemme research and see if I can find more information.

I believe the stock GD STi MAF housing is about 65mm. I don't think that will flow enough to support 450whp.

Blouch 2.5xtr 10 cm with the 2.4 inlet, TMIC, speed density and e85 should have no issue netting 450whp on a DynoJet with supporting mods. I would definitely add a ELH to that mix if you can.

Can the COBB Airbox be used? I've recently seen someone make 425 whp with more to go on a 05 STi with a FP Black with that intake.

P.S. with being stat reffed, don't they spot the fuel system mods (injectors/rails)?
 

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Found it!


JDM 85mm air box from a Version 6 STi.
 

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You can always push a setup like this to make that target goal. The problem will be how efficiently you make the power. That's where the differences will be. If you compare an aftermarket TMIC, turbo inlet, and airbox/intake to a stock setup, you'll find the aftermarket setup will make more power at the same boost, or the same power at less boost. Not only that, the width of the area under the curve will be improved.

E85 will help you out a lot though. I think that target will be dyno dependent though. Running an stage 2 setup (GD) on our Mustang dyno is at best 350whp on a really really good day, with E85.
 

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Discussion Starter · #5 ·
I remember around 2012ish there was someone running a stealthy TMIC with a blouch dom and a JDM STi air intake with drop in filter (MAF housing was 70mm) on a 2007 SWP STi. Lemme research and see if I can find more information.

I believe the stock GD STi MAF housing is about 65mm. I don't think that will flow enough to support 450whp.

Blouch 2.5xtr 10 cm with the 2.4 inlet, TMIC, speed density and e85 should have no issue netting 450whp on a DynoJet with supporting mods. I would definitely add a ELH to that mix if you can.

Can the COBB Airbox be used? I've recently seen someone make 425 whp with more to go on a 05 STi with a FP Black with that intake.

P.S. with being stat reffed, don't they spot the fuel system mods (injectors/rails)?
I will no longer be using the MAF sensor as i will be running speed density so I am aware that it will not support 450. Are you saying the 65mm tube size wont support 450whp? I sold my tomei elh and got a killer b holy header. The cobb air box last i heard this week they are in the process of getting it CARB approved. I watch smeedia on youtube man he did good work on that 2005 car. As far as fueling goes my car looks pretty much stock in the fueling department. I have a AEM340 in tank, id 1000's and a cobb flex fuel kit.
 

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Discussion Starter · #6 ·
Found it!


JDM 85mm air box from a Version 6 STi.
Could you point me in the direction of where i could possibly purchase one? Thanks for the info something i had no idea the JDM car uses a bigger airbox.
 

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Discussion Starter · #7 · (Edited)
You can always push a setup like this to make that target goal. The problem will be how efficiently you make the power. That's where the differences will be. If you compare an aftermarket TMIC, turbo inlet, and airbox/intake to a stock setup, you'll find the aftermarket setup will make more power at the same boost, or the same power at less boost. Not only that, the width of the area under the curve will be improved.

E85 will help you out a lot though. I think that target will be dyno dependent though. Running an stage 2 setup (GD) on our Mustang dyno is at best 350whp on a really really good day, with E85.
Totally understand what your saying, so the tuner will have to push it a little harder to make the same power on a restrictive intake setup. I do have a perrin inlet installed and was toying with the idea of getting an AEM CAI but dont like how the filter sits so low in the bumper and prone to water ingestion even though it hardly rains here in socal. Should I keep the K&N typhoon and run the stock snorkle? I am not against buying other intakes or using this KNN. Will they support the power even though the tube size is so close to the stock? Smeedia on youtube is running a cobb sf on his fp black and making 450. Is the cobb maf housing stock size?
 

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im not sure if this will help but the RA and 18? up use a different airbox...in my GR I cut the bottom out to clear my headlight and it looks like a stock air setup...could probably go stealthy with your cone filter into the airbox and black turbo inlet/afta maf hose...wont be blingy but will work
 

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With a silicone turbo inlet, you may run into collapsing the inlet using the stock airbox pushing the turbo pressure to net 450 whp.

It would be great if you could get the COBB shortram intake (especially with the heatshield box). I'm pretty sure that the MAF housing is 65mm since COBB doesn't note that a tune is REQUIRED. I'm sure it flows much better with an open filter element and smoother tube/hose vs. OEM.

Great to hear you are running a Equal length header, especially a Killer B (love mine!).

With a AEM340 in tank, id 1000's and cobb flex fuel kit; I think you'll need at least ID1300's and maybe hardwire the pump (depending on the dyno you are on shooting for 450 whp).

You will have to contact some of the larger JDM parts import companies and they should be able to source you a JDM 85mm air box from a Version 6 STi. I have noticed with most of the JDM engines for sale, they don't include the intake box, so they probably stockpile these kinds of parts?
 

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Discussion Starter · #10 ·
May 1st is the dyno appointment and still have time to think about what im going to do with the intake situation. I just got done building the car (again) after having to return to stock for state ref. Had to do valve seals as it would smoke only after start up and while I was in there installed ARP 2000 head studs, head gaskets, cobb ff, killer b holy header and up pipe, killer b cast oil pan and baffle, new exedy twin disc that makes nasty noises i love it haha.
 
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