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Premium Member
2007 Forester XT 4EAT-VTD
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2,138 Posts
Discussion Starter #1
As you know, I recently added the following items under the hood:

- Perrin TMIC replaced STi TMIC
- Samco turbo inlet replaced stock inlet
- AEM cold air intake replaced stock intake
- installed turbo blanket and Grimmspeed AOS

I replaced the TMIC first and I immediately noticed an improvement in throttle reponse. This makes sense as the Perrin has less pressure drop through it.

I then replaced the stock turbo inlet with the Samco, and maybe I felt a difference in throttle response (but maybe I didn't), in any case it was not significant like the TMIC.

Last week, I installed the AEM CAI and that too made a difference in throttle response, and some improvement in the higher RPMs as well.

Today, I returned to EFI Logics for a retune and here are the results - I gained 20 WHP but lost 16 ft./lbs. of torque at peak. Here is the dyno graph that tells the whole story;

Even though I lost 16 ft./lbs. of torque at the 3300 RPM peak, I gained torque from 3500 RPM all the way to redline, where I was up 23 ft./lbs.

WHP gain began at 3700 RPM and opened up by 5000 RPM for the 20 WHP gain at redline.

Maximum boost went from 19.3 to 20.2 at 3300 RPM and from 14.3 to 16.6 at redline.

Injectors are maxed out at 98%, but A/F ratio is maintained at around 11:1. I could gain a bit more with bigger injectors, but I won't do that until (or if) I upgrade the turbo.

With the revised throttle mapping that Chris uploaded last year in combination with these hardware upgrades and new tune, the car is really a pleasure to drive. Power delivery is smooth and very manageable. In all honesty, it feels much stronger than the dyno numbers indicate.

So I think I will drive it and enjoy it for now, until I decide I would like to do the polka...
 

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Registered
2006 Forester XT Limited 4EAT
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2,000 Posts
Very nice numbers, and you gotta love the areas that realized improvements!!
It always nice to see real gains after changing your build.
 

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2008 FSXT M/T
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4,167 Posts
so you lost a smidge of spool and tq but gained more hp. i think thats a good compromise, and you prolly couldnt feel the difference in lowend tq, but i bet she pulls much harder now to redline.
 

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05 FXT
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1,540 Posts
I'm going to say the down low portion is mostly a product of the IC, and the up top is a combination of the parts. If you were able to run that boost at redline previously, you probably would have been close. The GS BCS alone may have gotten you there, but the other mod's make it easier thus not working everything as hard and make the tune a little safer.

Overall good stuff, glad to hear you're happy and it should be good times to drive. Unfortunately you've hit the point of diminshing returns for your $$$ versus fun factor (as now you'll need a bigger turbo + injectors and the power additions get less and less noticeable), but it's still addicting! And thanks for sharing the journey.
 

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Premium Member
04 Acura TSX the slick 6 speed
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2,355 Posts
I've been excited about this thread for weeks. Congrats! Great results!

I spoke to the tuner about the 2.5XT-R and he agrees it's an awesome turbo. He thinks the Perrin TMIC will be OK though he would have to be conservative on the tune.

This place is bad for me (worse for my wallet)!
Uh oh...you've been tuned for one day and are already thinking about another turbo...this could be bad...less for the wallet than for your peace of mind!

Unfortunately you've hit the point of diminshing returns for your $$$ versus fun factor (as now you'll need a bigger turbo + injectors and the power additions get less and less noticeable), but it's still addicting! And thanks for sharing the journey.
Couldn't agree more, I found the same principal in my research. I think a Forester with a VF turbo is a beast and a good place to be. It's like that old Street Fighter game says when you win...

"Just remember, there are great fighters like you all over the world."

So my car is ridiculous fast but no matter how faster it gets, it will never be the fastest!!!

Congrats Canon on some good tuning results. 20psi is crazy...be careful.
 

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Premium Member
2007 Forester XT 4EAT-VTD
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2,138 Posts
Discussion Starter #10
Had a chance to drive it a little more today - the thing really rips through first and second to 80 MPH. Once it hits third gear triple-digit speed comes up mighty fast. For this old guy, it's really fast enough as is!

Also (by design), it doesn't drive like the typical VFxx turbo ugrade with the crazy surge when boost kicks in. The tuner did a great job of giving me plenty of "go-pedal modulation" and the onset of boost is very controllable. The first 40% or so of throttle feels like driving a "healthy" naturally-aspirated car, which makes for wonderful in-town casual driving.

I'm going to update my journal tonight with much more info on my goals, hardware selection and tune.
 

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Premium Member
2007 Forester XT 4EAT-VTD
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2,138 Posts
Discussion Starter #13
That is awesome. Still running stock injectors?
Yes. Chris said there was a tiny bit more available with larger injectors, but not enough to justify the expense.

The only other mod that still has me thinking is meth injection. Sqc146 just had a tune today at EFI Logics after installing the AEM kit and all I can say is HOLY CRAP!

Look Here
 

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2004 FXT 5MT
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1,142 Posts
Hmm Surgeline recommended larger (650cc at least) for my VF23, I think it is a little higher flowing turbo, maybe that's why.
 

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05 FXT
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1,540 Posts
You can max out stock injectors on a VF39/43/48 but it's right up at the edge and as far as I like to push the trans anyway.

In short, yes you could go to 650's and maybe get a hair more performance, but for the time and dollars to get an injector and eek out just a smidge more performance isn't worth it to me.

Hence my earlier statement that the $$$ to power gain after the VFxx phase starts getting hefty. There's just a fair amount more supporting mod required and extra risk involved.
 

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Official sf.org decal guy
2006 FXT
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12,367 Posts
Hmmmm... I'm sure your tuner is great, but that 98% IDC worries me. I know that a tuner put mine at 95% IDC on a VF34 @ 18psi (not sure what my A/F was) and within a year I had a headgasket go. I would really like to see you go to some larger injectors for the safety factor.
 

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2008 FSXT M/T
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4,167 Posts
The only other mod that still has me thinking is meth injection. Sqc146 just had a tune today at EFI Logics after installing the AEM kit and all I can say is HOLY CRAP!

]
well you asked for conservative, jim is looking for a more aggressive tune. im really suprised it made more power over the 100 octance. i could see the spool up, but its not even running that much more boost...



its really hard to compare cars on different days, but look @ this comparison. you vs jim w/ similar mods. he makes more power on less boost.. you even have a larger tmic and cai, wonder whats up w/ that.

 

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Premium Member
2007 Forester XT 4EAT-VTD
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2,138 Posts
Discussion Starter #18
its really hard to compare cars on different days, but look @ this comparison. you vs jim w/ similar mods. he makes more power on less boost.. you even have a larger tmic and cai, wonder whats up w/ that.

Yes, I've been looking at that for a while too. In all honesty, I was expecting at least 270 WHP with my current mods.

I did ask for a conservative tune, which may be part of it. Even though the injectors are at 98%, my A/F ratio is 11.1:1, a little rich IMO. If I was up closer around 11.5:1 or higher, I would be much more concerned about the injector duty.

So, I could spend the $$ for larger injectors, get re-tuned and gain little or nothing.

Or, I could look into doing meth injection which would also lower injector duty and make some significant gains too.
 

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Premium Member
2007 Forester XT 4EAT-VTD
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2,138 Posts
Discussion Starter #19
Hence my earlier statement that the $$$ to power gain after the VFxx phase starts getting hefty. There's just a fair amount more supporting mod required and extra risk involved.
And that sums up well where I am with it myself. I'm somewhat embarassed to admit that I haven't even jumped on it in first gear yet! My usual driving mode is very casual, and I suspect that most people on this forum use boost a lot more than I do. As I stated above, the only other mod I am considering at this point is meth injection - even though it's a PITA to deal with, it would greatly lower my injector duty, provide cooler exhaust temps and IMO be a great finishing touch to my current power mods.

One HUGE saving grace is that I do not need to use the FXT as my daily driver any more. I got back my 2003 Impala from our daughter who is graduating college next month, so I now use that for my 400 miles of commuting every week.
 
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