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Premium Member
2007 Forester XT 4EAT-VTD
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2,145 Posts
Discussion Starter #1
I'm still running 100% stock air intake with the VF48 turbo. I'm ready to make the upgrade and retune, so now the parts collection will begin. Here is what I'm looking at doing:

1. Gimmick turbo inlet
2. Gimmick after MAF pipe
3. Either APS 65mm CAI or the AEM CAI.
4. Possibly replace the '06 STi TMIC with a TXS TMIC

Any preferences on the CAI?

Is the Samco turbo inlet worth the extra $200 over the Gimmick?

Any other suggestions?

Thanks!
 

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Registered
2004 Subaru FXT MT
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1,853 Posts
I'm still running 100% stock air intake with the VF48 turbo. I'm ready to make the upgrade and retune, so now the parts collection will begin. Here is what I'm looking at doing:

1. Gimmick turbo inlet
2. Gimmick after MAF pipe
3. Either APS 65mm CAI or the AEM CAI. I personally like the APS
4. Possibly replace the '06 STi TMIC with a TXS TMIC

Any preferences on the CAI?

Is the Samco turbo inlet worth the extra $200 over the Gimmick?I don't think so

Any other suggestions?

Thanks!
A couple of thoughts in bold above^^
 

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Registered
07 FXT sport
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1,743 Posts
I have the prodrive (rebranded AEM) on the wrx and the 65mm aps on the fxt. They are both really nice units.

The AEM sits MUCH lower (almost behind the bugeye foglight) then the aps. Im not sure if this is a concern of yours but if it is the APS might be the better choice.

dm
 

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2008 FSXT M/T
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4,170 Posts
im looking to replace my spt sri w/ an aps 65mm myself. i also have a samco turbo inlet collecting dust, awaiting a turbo upgrade.
 

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Premium Member
2007 Forester XT 4EAT-VTD
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2,145 Posts
Discussion Starter #8
The AEM sits MUCH lower (almost behind the bugeye foglight) then the aps. Im not sure if this is a concern of yours but if it is the APS might be the better choice.
That is great info, thanks!

Filter access and winter icing are still a concern for me with a CAI. My only other thought is to modify the stock air box with a Beatrush Air Intake Funnel and a high-flow panel filter. This would be in combinatin with the turbo inlet and afterMAF pipe. Would be it wrong to think that this option (with my current level of power mods) would give me most of the gain of an APS or AEM?
 

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05 FXT
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1,540 Posts
I've written a fair amount on this previously. Sadly I didn't take pressure drop data in the past, but at VFXX power levels, I get the impression that huge gains won't be had w/ intake alone. I'm not saying they're bad to do either, and it will make the turbo work a little less hard.

I am a fan of the APS 70 I have which should fit incredibly similar to a 65. And yes, the MAF tube is as much of a restriction as the intake. I have a Gimmick afta-maf and w/ my Perrin inlet and APS, the fit wasn't perfect. I'm not sure who is at fault, but I had to cut and manipulate the afta-maf way more than I would have prefered.
 

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2004 XT
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3,205 Posts
before going rotated I had the perrin big maf and an APS 3in inlet(my tgv's are deleted) and the fit was great. I would recommend aps products. I am wary of having the maf located in the wheel well though. when my CAI was first built we had the MAF in the wheel well and it had problems with it when it got wet so we moved the sensor itself back into the engine bay and left the filter in the wheels well and it works great
 

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Premium Member
2008 FSXT 4EAT
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4,160 Posts
The APS inlet has been discontinued/back-ordered indefinitely. You're other choice for a 3" hard inlet is Agency Power, which leads to a whole other conversation. :biggrin:

After much debate and research, I plan on going with a Gimmick (or eBay) inlet. Have you looked into Zerosports for an after MAF tube? It looks a tad nicer than the GMS piece for almost the same price.




FWIW, my setup will be: Cobb short ram, Zerosports after-maf pipe, Gimmick/eBay inlet.
 

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The Sub kit guy
2005 Forester X & XT VF39
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13,100 Posts
So are there any proven gains with an intake?
I could see it helping with a larger than VFxx turbo, but i've heard an ythign smaller and your basically just adding noise. I"m not sure what to believe. I'm still using my fully stock intake system, but I'd upgrade if it would make a noticable difference.
 

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Premium Member
2008 FSXT 4EAT
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4,160 Posts
So are there any proven gains with an intake?
I could see it helping with a larger than VFxx turbo, but i've heard an ythign smaller and your basically just adding noise. I"m not sure what to believe. I'm still using my fully stock intake system, but I'd upgrade if it would make a noticable difference.
From what I've read, yes, an intake will increase gains if tuned for it, while the after-maf pipe and turbo inlet improve spool.
 

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Premium Member
2007 Forester XT 4EAT-VTD
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2,145 Posts
Discussion Starter #14
So are there any proven gains with an intake?
I could see it helping with a larger than VFxx turbo, but i've heard an ythign smaller and your basically just adding noise. I"m not sure what to believe. I'm still using my fully stock intake system, but I'd upgrade if it would make a noticable difference.
Based on the seemingly never-ending research I've done on this - and according to the guys at EFI Logics - there's some gain to be had. How much I think depends on a number of factors, but I think I should see perhaps 20 WHP from the intake upgrades.

When I installed the VF48, I was not 100% happy with the way the stock turbo inlet mated up with the turbo (the piece that attaches to the turbo seems mighty thin), so I may as well do the entire intake track.

I'll go for a retune in the spring and see how the numbers compare.
 

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05 FXT
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1,540 Posts
I've heard 20whp thrown as well, but based on my experience at even higher HP levels, I'd be incredibly hard pressed to believe that number.

And please explain how a "tune for it" would make a difference...
 

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Premium Member
2007 Forester XT 4EAT-VTD
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2,145 Posts
Discussion Starter #16
I've heard 20whp thrown as well, but based on my experience at even higher HP levels, I'd be incredibly hard pressed to believe that number.
Take a look at these graphs, especially at the curves above 3500 RPM;

'08 FXT 4EAT

My '07 FXT

Same dyno, same tuner.

The mods are almost identical. The first car has a SPT intake, mine is stock. Other than my GS PnP exhaust manifolds, both cars are modded almost identically.

The first car was tuned in January, so no doubt the colder air helped. Mine was tuned in August.

Yes, different cars on different days, but the difference in WHP seems consistent with everything I've read about the benefit of intakes, especially at higher RPMs.

My question has always been, compared to other cars with similar mods except an intake, why was mine about 25 HP less?

As far as "tuning for an intake" I'm not sure what tweaks can be made to optimize the intake modifications. But if I do this, I will get on the dyno again to see any improvements. I guess that's the only way I'll know for sure.
 

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The Sub kit guy
2005 Forester X & XT VF39
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13,100 Posts
I know when I got tuned Bobby said a 3" exhaust and an intake would net me another 25+whp, but I'm not sure which one gave you most the gains. I persoanlly will trade 25whp for the quiet of the stocker intake and STi exhaust.
 

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05 FXT
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1,540 Posts
Well, the plots do make sense to what you're saying. I'd be very curious to see how much air you're moving. As I recall from Tuned200's logs, I thought VFxx's get up to 270'ish g/s.

I will comment that my experiences were all on a stock mid-pipe in the exhaust which I believe is the bottle neck in my current setup. I've been meaning to mess w/ it.
 
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