Welcome to the North American Subaru Impreza Owners Club Sunday September 23, 2018
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Built Motor Discussion

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 09-13-2018, 12:18 PM   #1
WRXXXED
Scooby Newbie
 
Member#: 432652
Join Date: Oct 2015
Location: Gap, PA
Vehicle:
2010 Subaru WRX STI
61K (Gray)

Default Do i need a tune after aftermarket intake manifold?

Dont know if this thread is in the right discussion but i am running a built motor so i figured why not here...

Currently running a:

Speed density kit
Rotated 3582r
Stock intake manifold

My question is if i run an aftermarket intake manifold will i need a retune? I wouldnt think so because the manifold really just increases flow and the computer will just adjust for the increased flow of air. Just just asking for peoples opinions because im not expert.

Best reguards,
Aaron
* Registered users of the site do not see these ads.
WRXXXED is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 09-13-2018, 12:53 PM   #2
svynx
Scooby Specialist
 
Member#: 210371
Join Date: May 2009
Chapter/Region: MAIC
Location: York, pa
Vehicle:
2002 hybrid 16gxt
'03 Lifted TS

Default

IMO yes, you'll need a retune. Being that you are running a SD tune, anytime you change anything between the throttle body and the cylinders, you'd need a retune.

A good thread to read:
https://forums.nasioc.com/forums/sho....php?t=1906415
svynx is offline   Reply With Quote
Old 09-13-2018, 01:43 PM   #3
mrsaturn7085
Scooby Specialist
 
Member#: 375462
Join Date: Dec 2013
Chapter/Region: NWIC
Location: Portland, OR
Vehicle:
2006 Impreza WRX STI
WR Blue

Default

Yes, you need a re-tune. Period.
mrsaturn7085 is offline   Reply With Quote
Old 09-13-2018, 06:01 PM   #4
bp05obxt
Scooby Newbie
 
Member#: 459799
Join Date: Dec 2016
Default

Quote:
Originally Posted by mrsaturn7085 View Post
Yes, you need a re-tune. Period.


Ditto
bp05obxt is offline   Reply With Quote
Old 09-13-2018, 10:57 PM   #5
mrbunz
Scooby Newbie
 
Member#: 491437
Join Date: Sep 2018
Vehicle:
2007 Subaru wrx sti
blue

Default

Definitely need a re tune
mrbunz is offline   Reply With Quote
Old 09-13-2018, 11:32 PM   #6
WRXXXED
Scooby Newbie
 
Member#: 432652
Join Date: Oct 2015
Location: Gap, PA
Vehicle:
2010 Subaru WRX STI
61K (Gray)

Default

Got it. Need a retune
WRXXXED is offline   Reply With Quote
Old 09-14-2018, 01:03 PM   #7
kellygnsd
Scooby Guru
 
Member#: 32669
Join Date: Feb 2003
Chapter/Region: SCIC
Location: Woodland Hills
Vehicle:
2007 2.34LR, EFR7670
LINK G4+ hybrid STi

Default

Quote:
Originally Posted by svynx View Post
IMO yes, you'll need a retune. Being that you are running a SD tune, anytime you change anything intake and the exhaust, you'd need a retune.

A good thread to read:
https://forums.nasioc.com/forums/sho....php?t=1906415
Fixed
kellygnsd is offline   Reply With Quote
Old 09-14-2018, 01:52 PM   #8
BlackFighter
Scooby Specialist
 
Member#: 193940
Join Date: Nov 2008
Location: Philly
Vehicle:
2004 WRX STI Black
RalliSpec Shortblock

Default

No you don't get it, YOU NEED A RE-TUNE

J/K but with our cars you almost need a retune when you change anything.
BlackFighter is offline   Reply With Quote
Old 09-14-2018, 03:32 PM   #9
subaru_gc8
Scooby Specialist
 
Member#: 29292
Join Date: Nov 2002
Chapter/Region: SCIC
Location: Orange County CA
Vehicle:
2004 WRX wagon
silver

Default

Quote:
Originally Posted by WRXXXED View Post
Dont know if this thread is in the right discussion but i am running a built motor so i figured why not here...

Currently running a:

Speed density kit
Rotated 3582r
Stock intake manifold

My question is if i run an aftermarket intake manifold will i need a retune? I wouldnt think so because the manifold really just increases flow and the computer will just adjust for the increased flow of air. Just just asking for peoples opinions because im not expert.

Best reguards,
Aaron
so will you need one, sure its always good to have the tune match the upgrades. if you are using the stock ecu. it compensate for it some what. a bigger intake manifold will flow more air so im assuming that you will probably lean out more on the low side of the rev range. honestly you stock comp will compensate before the cel comes on. if you don't want to get a tune, just start out slow and build up to full throttle to see what your trims look like. that will tell you more than some guy on the internet thats never tuned a car before So basically datalog datalog datalog and check your trims
subaru_gc8 is online now   Reply With Quote
Old 09-14-2018, 04:01 PM   #10
bp05obxt
Scooby Newbie
 
Member#: 459799
Join Date: Dec 2016
Default

Quote:
Originally Posted by subaru_gc8 View Post
so will you need one, sure its always good to have the tune match the upgrades. if you are using the stock ecu. it compensate for it some what. a bigger intake manifold will flow more air so im assuming that you will probably lean out more on the low side of the rev range. honestly you stock comp will compensate before the cel comes on. if you don't want to get a tune, just start out slow and build up to full throttle to see what your trims look like. that will tell you more than some guy on the internet thats never tuned a car before So basically datalog datalog datalog and check your trims


This is how forums cause issues. The basis of what is being said here is fundamentally flawed. Cars are tuned in order to adjust parameters for different parts. As it was mentioned the ecu can adjust/adapt in certain ways to allow the car to “run” but it doesn’t mean it is right. If the ecu truly relearned and set parameters there would be no need to “tune” the car in the first place.

I get what is being said here, but to play around with something like this and test or try it out to see what happens seems silly. Data logging to wait until something isn’t right is backwards.

Bottom line get a tune when you change things.

If you are close to where the car is getting tuned maybe you can drive it there gently. I hope at least you have an AFR gauge to make sure it is okay in light load. Stay out of boost or heavy load.....
bp05obxt is offline   Reply With Quote
Old 09-14-2018, 04:25 PM   #11
kellygnsd
Scooby Guru
 
Member#: 32669
Join Date: Feb 2003
Chapter/Region: SCIC
Location: Woodland Hills
Vehicle:
2007 2.34LR, EFR7670
LINK G4+ hybrid STi

Default

A MAF based tune would compensate better to this change that a SD tune. On a SD tune you will be following more air into the engine at the same rpm and MAP level and the only way your SD tuned ECU will know this is with a re-tune.
kellygnsd is offline   Reply With Quote
Old 09-14-2018, 08:00 PM   #12
subaru_gc8
Scooby Specialist
 
Member#: 29292
Join Date: Nov 2002
Chapter/Region: SCIC
Location: Orange County CA
Vehicle:
2004 WRX wagon
silver

Default

Quote:
Originally Posted by bp05obxt View Post
This is how forums cause issues. The basis of what is being said here is fundamentally flawed. Cars are tuned in order to adjust parameters for different parts. As it was mentioned the ecu can adjust/adapt in certain ways to allow the car to “run” but it doesn’t mean it is right. If the ecu truly relearned and set parameters there would be no need to “tune” the car in the first place.

I get what is being said here, but to play around with something like this and test or try it out to see what happens seems silly. Data logging to wait until something isn’t right is backwards.

Bottom line get a tune when you change things.

If you are close to where the car is getting tuned maybe you can drive it there gently. I hope at least you have an AFR gauge to make sure it is okay in light load. Stay out of boost or heavy load.....
lol so my question is how much more air is it going to flow it you dont mess with the wastegate duty or just changing the intake manifold? I personally would never put my car on the edge of tuning so yeah. as far as needing a tune, you probably should but what I am saying is it will run. just watch your fuel trims and your afrs, if they start to get a little out of control, just let off the gas.

as for the datalonggin, how do you think tuners know when somethings not right? they dont guess they datalog.... im assuming you have never tuned a car and if that is the case how would you know?

as for Kelly I do have a question, do if your map sensor is running off the manifold pressure, how is the pressure going to change if there is not more air being forced into the manifold, the biggest problem would be more air getting into the heads at the begining of a run but afterwards I was told a bigger manifold doesnt really make that big of a difference.
subaru_gc8 is online now   Reply With Quote
Old 09-15-2018, 01:17 AM   #13
mrsaturn7085
Scooby Specialist
 
Member#: 375462
Join Date: Dec 2013
Chapter/Region: NWIC
Location: Portland, OR
Vehicle:
2006 Impreza WRX STI
WR Blue

Default

Because speed density is an estimation based on a model you create and MAF-based fueling is a measurement using a sensor. Yes, in the end they are both an estimation of air mass... but MAF fueling is a more direct measurement. The downside of course is that MAF controlled fueling will flat-out stop working with an air leak large enough while a speed density setup will let you blow an intake hose and keep running. This is why SD is generally the choice for everything from tuned to full motorsport cars; it is just more reliable.

Kelly is correct in his logic - speed density will always require a tune. Period.

With MAF-based fueling in an ideal scenario, you could change every part of the motor and it would still run. There are, in fact, motor swaps that can be done safely without even retuning using a good MAF based system.
mrsaturn7085 is offline   Reply With Quote
Old 09-15-2018, 01:21 AM   #14
kellygnsd
Scooby Guru
 
Member#: 32669
Join Date: Feb 2003
Chapter/Region: SCIC
Location: Woodland Hills
Vehicle:
2007 2.34LR, EFR7670
LINK G4+ hybrid STi

Default

Quote:
Originally Posted by subaru_gc8 View Post
as for Kelly I do have a question, do if your map sensor is running off the manifold pressure, how is the pressure going to change if there is not more air being forced into the manifold, the biggest problem would be more air getting into the heads at the begining of a run but afterwards I was told a bigger manifold doesnt really make that big of a difference.
A good aftermarket intake manifold can gain you 30+ whp or more on the top end depending on the setup. That 30+whp is a result of the increased volumetric efficiency of the setup, or in simple terms, for the same boost level the engine is flowing more air, therefore making more power.

Most VE based speed density systems are tuned MAP vs RPM in a 3D table. Your old fuel table accounted for X amount of air at what ever arbitrary load point but now the engine is actually flowing 30+ more whp worth of air that could lead to problems. That is not a small % change in airflow a could lead to possibly dangerous lean conditions.

With a MAF based tune, since you are measuring airflow entering the engine directly, changing the manifold is not as big of an issue since the increased flow is accounted for as long as your MAF is not maxed out. You should still datalog though.
kellygnsd is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 03:51 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2018 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.