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Old 09-09-2010, 09:39 PM   #1
00LGTP
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Default 05+ manifold project

i am currently in the process of putting a 07 2.5i IM on my 2.5rs.

im pretty sure i have everything i need planned out, just need to get parts and physically do it.

i have found very little info about people doing this, which is why i wanted to see what info you guys have obtained.

any info will be helpful, im open to all suggestions.
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Old 09-11-2010, 01:35 AM   #2
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The only difficulty is in mounting the throttle since you have a cable throttle and the 05+ IM is for DBW. There's some brackets and things you'll have to have custom fabbed at a machine shop to allow the cable throttle to function.
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Old 09-12-2010, 10:33 PM   #3
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and fab some sort of port for the Idle air to flow through. My best idea right now is to hog out the hole in the TB, tap an AN Pipe-flare fitting in and do the same somewhere on the intake manifold.
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Old 09-12-2010, 10:34 PM   #4
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Isn't the entire idle-air apparatus integrated into the throttle body?
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Old 09-14-2010, 11:40 PM   #5
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i compared gaskets and came to the conclusion that my stock RS TB will bolt up, but that stupid IACV passage has to be in the way.

i have a TB spacer, so i block it off on the manifold side, drill a hole/install fitting, run a hose from that fitting to the IM plenum.

done!

cable will be easy, small bracket.

the map sensor!

im going to port out on of the EGR holes, only need about a 1/8" all the way around, polish it up nice and pray i did a good job and that O ring will seal. i can always use sensor save gasket sealer.

bolting it up will be no harder of bolting on another plate to the stock EGR threads and drilling holes with bolts for the map.


you guys know it will work!

if you guys get a chance, let me know what you think about this for the fuel system.

http://www.rs25.com/forums/f13/t1427...-his-hose.html
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Old 09-15-2010, 11:39 AM   #6
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Nice! Thanks for putting this out there for everyone.

Aside from zzyzxx running one in the 300hp NA car, does anyone have any info on the gains that can be achieved by swapping to the newer manifold?

Jacob
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Old 09-15-2010, 05:31 PM   #7
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Quote:
Originally Posted by renob123 View Post
Nice! Thanks for putting this out there for everyone.

Aside from zzyzxx running one in the 300hp NA car, does anyone have any info on the gains that can be achieved by swapping to the newer manifold?

Jacob
i havent found anything, which is why i made this thread.

more brains on the job is a good thing.
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Old 09-15-2010, 05:33 PM   #8
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Quote:
Originally Posted by 00LGTP View Post
i havent found anything, which is why i made this thread.

more brains on the job is a good thing.
Ahh, so you plan to post some of the gains or a flowbench or something? I'm very interested.

Jacob
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Old 09-15-2010, 05:39 PM   #9
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ill post pics and explain how i did things but i cant be bothered by a flowbench.

dont get me wrong i would love too, but im a full time college student and (Automotive Technology and Management) i have limited time.
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Old 09-15-2010, 05:47 PM   #10
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Quote:
Originally Posted by 00LGTP View Post
ill post pics and explain how i did things but i cant be bothered by a flowbench.

dont get me wrong i would love too, but im a full time college student and (Automotive Technology and Management) i have limited time.
That's cool. I was asking about gains, and you said that was why you made this thread. I'd call it more of a how-to, which is great, but I wanted to see the gains.

Jacob
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Old 09-15-2010, 05:52 PM   #11
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Quote:
Originally Posted by renob123 View Post
That's cool. I was asking about gains, and you said that was why you made this thread. I'd call it more of a how-to, which is great, but I wanted to see the gains.

Jacob
lol yea guess " how to" is more like it.

butt dyno for now, real dyno when the chance pops up in the future.
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Old 09-15-2010, 05:55 PM   #12
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Quote:
Originally Posted by 00LGTP View Post
lol yea guess " how to" is more like it.

butt dyno for now, real dyno when the chance pops up in the future.
Cool. Until then, does anyone else have any ideas of the actual gains from this swap? I've never heard of any. I've just heard zzyzxx saying they used it.

Jacob
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Old 09-16-2010, 08:33 AM   #13
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Contact 42 Autosports. They've done it and came to the conclusion that the stock intake tract can't provide enough air to make it an all out winner. There are more details, but you should contact them to get the whole story.

Jay
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Old 09-17-2010, 02:02 PM   #14
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Quote:
Originally Posted by Storm View Post
They've done it and came to the conclusion that the stock intake tract can't provide enough air to make it an all out winner.

Jay
So what you are saying is that the heads outflow the stock intake?
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Old 09-17-2010, 02:51 PM   #15
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Originally Posted by RaineMan View Post
So what you are saying is that the heads outflow the stock intake?
i think he means the stock intake tubing cant flow enough to see gain.

its not all about the volume of air, the runner lengths are long and P&P from the factory.
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Old 09-17-2010, 02:57 PM   #16
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Quote:
Originally Posted by 00LGTP View Post
i think he means the stock intake tubing cant flow enough to see gain.

its not all about the volume of air, the runner lengths are long and P&P from the factory.
OK... I think I get you. The IM can handle more flow than the stock tubing and filter provide. Certainly an good case for intake modification if I've ever seen one.

What about the heads? Can they handle more air than the stock intake can provide as well? Generally that's where you hit a wall when it comes to NA engines... if the heads flow less CFM than the IM or intake tubes then modifying the intake won't do you any good anyways.
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Old 10-05-2010, 08:08 PM   #17
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Quote:
Originally Posted by 00LGTP View Post
i think he means the stock intake tubing cant flow enough to see gain.

its not all about the volume of air, the runner lengths are long and P&P from the factory.
The intake, pre throttle body, is fine for flow. It doesn't limit the car in any way. You can remove all of it and have just the throttle body itself, and there will be zero gains in power up top. The intake piping simply is not restrictive.

What is restrictive is the head/cam. Subaru designs the intake system to flow the same throughout. This means the throttle body, intake manifold, heads, and cams are all geared to flow the same amount and have the same velocity. This of course makes the system share the same restriction. If you increase intake manifold flow, you need to also increase the flow through the heads. This means porting. The cams will also have their own design limitations and are geared for the stock hardware. The exhaust manifold will be designed for stock flow too.

Effectively you want to scale up everything from the start of the intake piping to the end of the exhaust tail pipe. Uneven sizing and restrictions anywhere can limit overall gains.






Is that bracket for the MAP? The runner will exhibit sizable pressure variations in the runner. I question if the MAP reading will be decent enough to be useful. It really should be reading from the center of the plenum area like it is on the older manifold. I'm not sure how ell the ECU will like what it measures from a runner.
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Old 10-05-2010, 08:17 PM   #18
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Quote:
Originally Posted by Back Road Runner View Post
The intake, pre throttle body, is fine for flow. It doesn't limit the car in any way. You can remove all of it and have just the throttle body itself, and there will be zero gains in power up top. The intake piping simply is not restrictive.

What is restrictive is the head/cam. Subaru designs the intake system to flow the same throughout. This means the throttle body, intake manifold, heads, and cams are all geared to flow the same amount and have the same velocity. This of course makes the system share the same restriction. If you increase intake manifold flow, you need to also increase the flow through the heads. This means porting. The cams will also have their own design limitations and are geared for the stock hardware. The exhaust manifold will be designed for stock flow too.

Effectively you want to scale up everything from the start of the intake piping to the end of the exhaust tail pipe. Uneven sizing and restrictions anywhere can limit overall gains.






Is that bracket for the MAP? The runner will exhibit sizable pressure variations in the runner. I question if the MAP reading will be decent enough to be useful. It really should be reading from the center of the plenum area like it is on the older manifold. I'm not sure how ell the ECU will like what it measures from a runner.

i have every else supporting mod.

Im tnice17 on RS25 and we met up at the ECS meet, now i think you remember me and my car.

yes its for the map. i didnt want to risk welding on the cast aluminium and after talking to a few of my instructors they said it should be good enough for an accurate reading.

some GM MAP sensors are mounted on the firewall and has a small hose going from the intake manifold to the sensor. so i think my location will be ok. well we will find out!

im going to use the 07 injectors with a modified 00/07 rail and RPR
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Old 09-17-2010, 01:49 PM   #19
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^^ send them an email, waiting for a reply.

does anyone know if stock 2.5i injectors will work with a WRX/STI aftermarket fuel rail?

gotta spend a certain amount on a FPR, so might as well do it while i have it apart and do a fuel rail/FPR combo. ebay sells come kits with lines and everything i need. normally i wouldnt mess with ebay stuff but machined aluminum is machined aluminum.
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Old 09-17-2010, 04:18 PM   #20
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Exactly.....the torquebox made for pre-05 cars has a small inlet and the CAI they developed for those cars ended up not being a good match for that manifold. The torquebox made for that unit was better, but still short of what they had prior to bolting it on. IIRC, the best gains came from a 4" cone filter (from a GTR) taped directly onto the TB.

The smaller volume of the 05 torquebox works well enough, but the inlet to it needs opened up substantially to let it work.

Jay
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Old 09-17-2010, 04:24 PM   #21
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So I take it the intake was redesigned for 06+? Just trying to figure out where my car fits in this.
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Old 09-17-2010, 04:48 PM   #22
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Quote:
Originally Posted by RaineMan View Post
So I take it the intake was redesigned for 06+? Just trying to figure out where my car fits in this.
you already have the manifold i am putting on.

here is the fuel rail/line kit i was talking about earlier.

http://cgi.ebay.com/ebaymotors/High-...mZ280562461348
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Old 09-18-2010, 09:13 PM   #23
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Quote:
Originally Posted by 00LGTP View Post
you already have the manifold i am putting on.

here is the fuel rail/line kit i was talking about earlier.

http://cgi.ebay.com/ebaymotors/High-...mZ280562461348
anyone have an opinion?

FPR- maybe get another one, but the rails and lines are rails and lines.

the 08 WRX injectors(blue) and 2.5i (yellow) are the same, i just need to know if the distance from the center of the injector bore to the other. might work, fabbing a bracket for the rail would be easy.

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Old 09-17-2010, 04:56 PM   #24
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Quote:
Originally Posted by RaineMan View Post
So I take it the intake was redesigned for 06+? Just trying to figure out where my car fits in this.
05 and 06 are pretty much the same. The big change is between 04 and 05.
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Old 09-17-2010, 05:37 PM   #25
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Quote:
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05 and 06 are pretty much the same. The big change is between 04 and 05.
And 07 is identical to 06 then?
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