Jump to content
LegacyGT.com

Mishimoto (2015 WRX) Intake Fitment on 5th Gen LGT

acumenhokie

Recommended Posts

Mishimoto Newbie

Mishimoto

Posted
Posted
Well gents I have some news and it isn't good. It's blatantly obvious that every part on the 15 WRX is a knock off version of our car but everything has been tweaked just enough that nothing will fit directly. Take a look at the album I posted for details but basically everything is the same basic part with some minor tweaks and all the piping for the 2.0L is slightly smaller than that of the 2.5L. Mounting points require just enough of a rotation to make fitment slightly off. This goes for the piping and box as well as charge pipe. We took a look at the radiator and it would be a very very tight fit with the racerX larger charge pipe. The other issue is that the mounting brackets point outward on the WRX while they point inward on our car. Again, just enough so that nothing fits exactly.

 

More details and side by side posts in the picasa album below. I've also commented on the picture to point out what's different fitment wise. Big shout out goes to John and all the guys at Mishimoto for taking the time to test this for the community and for showing me around the facility. Great to meet everyone.

 

https://plus.google.com/photos/109780854372699670398/albums/6053123623836317681

 

Thank you very much for volunteering your vehicle and time for the test fitting of this intake setup. It is too bad there are so many differences between the two intake systems.

 

We just installed this intake on my brother's 2015 WRX last weekend and in stock form, the MAF placement is a flow measurement nightmare.

 

A royal pain to tune and calibrate the MAF readings.... all because of the proximity of the MAF housing to the cone filter. Ideally, the MAF housing should be another 3-6 inches further downstream on the elbow section (inside the fender) leading to the turbo... but that would require a MAF cable extension.

 

Rob @ AMR Performance will or already has contacted Mishimoto re this.

 

Adding a better flowing non-cone filter caused the car to run super rich (9 or 10:1) at idle, and exceeded the voltage/flow rate limits of the stock MAF sensor beyond 4K RPM, pegging the flow @ 300g/sec, while in reality the car ran extra lean (16:1). On the LGT its likely possible to re-scale and extrapolate this, on the 2015 WRX - not yet.

 

With that the intake components are good quality, even the seemingly flimsy silicone couplers do no collapse under <21-22psi of boost. It sounds great under WoT, engine breaking, turbo spool up.

 

With a re-tune, the WRX picked up an additional 40-55 ft-lbf wtq from 2-3K RPM and maybe 15-20 ft-lbf from 4.2-5K RPM. A modest peak wHP gain of 6-8HP.... but the low-end torque gain and the turbo spool up sound itself was well worth it. Target boost raised to 19psi, a notch above the safe target without the intake.

 

40-55ft-lbf wTQ and 15-30 wHP gain from 2-3K RPM

20ft-lbf wTQ and 10-20 wHP gain from 4.2-5K RPM

6-8 peak wHP gain

 

Here are some tips that might help make things smoother for you acumenhokie:

 

If you can, pickup a 3" ID Dryflow filter to replace their oiled element that comes in the kit and if you opt for a 5" long AEM one (leaving some working room in the airbox), you can see about adding 1-2" of piping or reinforced silicone coupler to create some distance between the filter element and the MAF location. I bet it will help the engine run better as-is or help to make a re-tune easier.

 

If you install the kit as-is, you'll most likely be running lean and it will be tricky (but not impossible) to re-calibrate everything under all load conditions to stabilize the AFRs, long/short term fuels trims, timing advance, etc. This is mainly because of the MAF housing location in reference to the cone filter in this design.

 

As mentioned on other forums, our intake functions perfectly with the stock tune and has been thoroughly tested. Our data has been posted in the response below.

 

As we’ve mentioned before, this intake is not compatible with a cat-back exhaust on the stock tune, this is what is likely causing your overly-lean AFR conditions. We also experienced lean AFR’s with our cat-back equipped test vehicle, which is why we do not recommend using the two together without a tune. To reiterate: our statement that the intake does not require a tune is for an otherwise completely OEM vehicle.

 

Even though your testing is not a valid apples to apples comparison with ours since a CBE was installed we’d still like to address some of the issues and claims you mentioned. MAF readings were not an issue during our testing, idle conditions were also nearly identical to use with the stock intake. The first chart below shows the AFR values at idle for both the OEM and Mishimoto intakes. As you can see they’re very similar: the largest variation between the two is only 3%. During the weeks of testing our WRX we never once noticed any sort of idle issues. The second chart shows the calculated mass air flow during a WOT dyno pull. As you can see the calculated Mass Air Flow is not anywhere close to reaching the sensor’s upper limit. Could you please provide us with the datalog showing the CMAF reaching 300 g/s? It’s very surprising that a CBE causes a 46% increase in calculated mass air flow.

 

http://i60.tinypic.com/291pcn6.png

 

http://i62.tinypic.com/dc9f2p.png

 

MAF location relative to the filter is not going to result in any problems. In fact, the MAF sensor distance to the filter is essentially identical between the stock housing and the Mishimoto housing. The image below displays the distance from the MAF to the end of the intake tube. How did you come up with the conclusion that MAF sensor placement would have any effect on AFRs? Have you conducted any testing to show this? The MAF sensor placement was designed as such partially because a lower location would require cutting and splicing wires (as you’d mentioned) but mainly because previous intake testing has shown us that MAF location makes no difference if the cross sectional area remains constant.

 

http://i59.tinypic.com/2drbdol.jpg

 

The figures below show the AFR readings for the OEM intake and the Mishimoto intake after the car was driven for at least 200 miles and the ECU had a chance to adjust itself. Both AFR curves are similar until the ECU enters open loop at which point the Mishimoto intake becomes slightly leaner yet still within a safe operating range.

 

http://i59.tinypic.com/es14t0.png

 

http://i61.tinypic.com/24q4ghg.png

 

We have conducted around 150 dyno runs without any knock events recorded. Our only knock event recorded was during recent testing/tuning of our prototype downpipe.

 

As far as fuel trim is concerned, you mentioned that “we notice the vehicles short term fuel trim (STFT) and long term fuel trim (LTFT) are not steady.” We would have to agree with this, as the fuel trim readings are in place to show the ECU corrections to adjust the fuel mixture to reach desired values. These values will be oscillating on both the stock intake and the Mishimoto intake. Can you please provide more detail/data points regarding the amounts of fluctuation you experienced?

 

Also, was your testing done immediately after resetting the battery and/or installing the intake? If the ECU did not have a chance to properly adjust itself for the additional air flow then the constant fluctuations in fuel trims are normal. This is all described in the engineering report that was written for the intake. Check out the link below for more information.

 

http://lib.store.yahoo.net/lib/yhst-62631657248580/MMAI-WRX-15-EngineeringReport.pdf

 

Again, although leaner than the stock intake setup, the results from the Mishimoto intake are very safe to run on the stock tune. We also experienced identical AFR readings at idle for both intakes; no fluctuations or other concerns were exhibited.

 

As we mentioned, this intake will function with the factory tune and provide safe AFR’s while providing improved power. As with any performance upgrade, accompanying it with a tune will provide even greater gains. We are offering free tunes for each of the power-adding products we release. These tunes are compatible with the EcuTek device and we have already produced substantial gains.

Link to comment
Share on other sites
Perscitus Veteran

Perscitus

Posted
Posted
Thank you very much for volunteering your vehicle and time for the test fitting of this intake setup. It is too bad there are so many differences between the two intake systems....
Thanks Mishimoto.

 

If or when you get a chance - please log STFT/LTFT (Bank 1), AFRs (commanded and measured), RPM, Load, MAF (g/sec and or voltage) not during WOT pulls or a few seconds at idle.... but a 30-60 mile trip of mixed driving. Cold start, warm up, highway, acceleration events, engine braking, idling. Warm start.

 

Dyno or street WOT pulls won't fully expose the issues we've seen.

Almost all happen between 0 and ~ 25-30% throttle, across multiple load conditions, irrespective of vehicle or engine speeds.

 

Please contact Rob @ AMR for tuner to manufacturer feedback.

Link to comment
Share on other sites
acumenhokie Mentor

acumenhokie

Posted
  • Author
Posted
Any chance we can get a limited run of intakes that would fit the legacygt? GB anyone?

 

The other option would be just to replicate the intake pipes or coolant pipes. It would be the same as the Samco offering but cheaper and more widely available. We saw during the test fit that 1 out of 2 of the intake ones is already a direct fit.

 

See this thread for more info:

http://legacygt.com/forums/showthread.php/samco-intake-and-coolant-lines-210144.html?t=210144

Link to comment
Share on other sites
4thsubaru Collaborator

4thsubaru

Posted
Posted
The other option would be just to replicate the intake pipes or coolant pipes. It would be the same as the Samco offering but cheaper and more widely available. We saw during the test fit that 1 out of 2 of the intake ones is already a direct fit.

 

See this thread for more info:

http://legacygt.com/forums/showthread.php/samco-intake-and-coolant-lines-210144.html?t=210144

 

Thanks I missed that. I really like the closed box. I wounder if we can just purchase the box assuming that part was bolt on and intake box

Link to comment
Share on other sites
  • 1 year later...
GTEASER Grand Master

GTEASER

Posted
Posted
The Mishimoto intake from a 2015 WRX fits our 5th gen lgts I have it installed on my 2010 lgt

 

 

Pic please of how you resolved the issue of the 2015 WRX MAF sensor being different than ours and MAF sensor housing actually working with our MAF sensor.

 

You've shown how 75% of this fits, but not the key portion.

GTEASER's 2012 Legacy GT - Sold

GTEASER's 2009 XTeaser - Sold

GTEASER's 1992 Legacy SS - Sold

Link to comment
Share on other sites
  • 3 weeks later...

Archived

This topic is now archived and is closed to further replies.

Go to topic listing


×
×
  • Create New...

Important Information

Terms of Use

  I accept