Welcome to the North American Subaru Impreza Owners Club Wednesday August 27, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Factory 2.5L Turbo Powertrain

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 11-15-2012, 04:40 AM   #1
JBones81
Scooby Newbie
 
Member#: 304046
Join Date: Dec 2011
Location: NorCal
Vehicle:
2013 BMW 335i
blue

Default Next round of mods...need more fuel yet?

Car is 2012 WRX sedan:

Currently, I have the Cobb SF intake/box and their ots stage 1 on accessport, and the nameless performance muffler delete setup. I'm gonna order the cobb catted dp, and do the stage 2 map...was also really leaning toward doing the process west top mount ic, and then getting it pro tuned. If I'm gonna go beyond the dp and stage 2 to add the tmic and protune, do I need to start upgrading the fuel system at all prior to wrapping it up, or am I ok unless I go beyond the listed mods??

fwiw, I'm in Northern CA and can't get better than 91 anywhere...and it's tuned by cobb on that AZ, NV, CA tune cause apparently our gas is that bad

thoughts at this point in mods??
* Registered users of the site do not see these ads.
JBones81 is offline   Reply With Quote
Old 11-15-2012, 06:47 AM   #2
GrumpyPitbull
Scooby Specialist
 
Member#: 313311
Join Date: Mar 2012
Chapter/Region: MWSOC
Location: Twin Cities, MN
Default

Your going to get differing opinions on this. Its a support mod, so many people feel you should not do it unless absolutely necessary.

Me personally, I would check the idc and if it is over 90% I would upgrade the injectors and pump. My feeling is if you going to spend thousands on parts .. why not spend an extra 500 or so to ensure your fuel system is up to snuff.

You will likely be around 95% at stage 2 with a tmic .. some have even reported being at 95 with just a stage 2 ots map. I suspect it is one of the reasons we see so many pistons popping on stage 2 cars ... But that's purely my own speculation.
GrumpyPitbull is offline   Reply With Quote
Old 11-15-2012, 06:53 AM   #3
HinshawWRX
Medium Frank
Moderator
 
Member#: 140114
Join Date: Feb 2007
Chapter/Region: MAIC
Location: Common Sense, VA
Vehicle:
2014 Porsche
GT3 (Currently on Fire)

Default

Your injectors will be CLOSE to maxed, but not enough to require injectors.

So needed? No. Decent upgrade before a protune to ensure room for growth? Sure.
HinshawWRX is offline   Reply With Quote
Old 11-15-2012, 08:26 AM   #4
xluben
Scooby Guru
 
Member#: 261612
Join Date: Oct 2010
Location: Minneapolis, MN
Vehicle:
2012 Forester 2.5X
2002 WRX Sedan

Default

Quote:
Originally Posted by HinshawWRX View Post
Your injectors will be CLOSE to maxed, but not enough to require injectors.

So needed? No. Decent upgrade before a protune to ensure room for growth? Sure.
Agreed.
xluben is online now   Reply With Quote
Old 11-15-2012, 09:30 AM   #5
drewvdw
Scooby Guru
 
Member#: 255776
Join Date: Aug 2010
Chapter/Region: MWSOC
Location: Laramie, WY
Vehicle:
2010 LR WRX
MPS powered.

Default

What these guys are saying. After tuning a few 09+ WRX's my tuner highly recommended fuel pumps and injectors to go in with an intercooler and/or downpipe.
drewvdw is online now   Reply With Quote
Old 11-15-2012, 09:48 AM   #6
xluben
Scooby Guru
 
Member#: 261612
Join Date: Oct 2010
Location: Minneapolis, MN
Vehicle:
2012 Forester 2.5X
2002 WRX Sedan

Default

As long as you have a good tune you should be fine. The fuel system will probably be the limitation, but the extra $500 you'll spend on fuel will probably only get you 5% more power at most. Worth it if you're going for more later, but maybe not if this is all the further you want to mod.
xluben is online now   Reply With Quote
Old 11-15-2012, 11:12 AM   #7
thisisntjared
Scooby Specialist
 
Member#: 177891
Join Date: Apr 2008
Chapter/Region: Tri-State
Location: south jersey
Vehicle:
06 wrx wagon
child seat/tow hitch cgm

Default

Quote:
Originally Posted by xluben View Post
As long as you have a good tune you should be fine. The fuel system will probably be the limitation, but the extra $500 you'll spend on fuel will probably only get you 5% more power at most. Worth it if you're going for more later, but maybe not if this is all the further you want to mod.
i agree with this. if you were to go e85 or get a bigger turbo, that is when you will be genuinely annoyed with your current fuel ceiling. but until then, and especially if you are not having a custom tune on a dyno, the limits of your current fueling wont aggravate you.

you could just wait to upgrade fuel at the same time you have a custom tune done for other big power upgrades
thisisntjared is offline   Reply With Quote
Old 11-16-2012, 04:28 AM   #8
JBones81
Scooby Newbie
 
Member#: 304046
Join Date: Dec 2011
Location: NorCal
Vehicle:
2013 BMW 335i
blue

Default

ok, so I get that upgrading fuel components would be a solid move, pending future upgrades, but now I'm concerned (from reading response above) that I'll be so close to maxxing my stock fuel system's capabilites just with a downpipe and stage 2...

before starting this thread, I hadn't heard this concern. Should I be worried?
JBones81 is offline   Reply With Quote
Old 11-16-2012, 06:57 AM   #9
HinshawWRX
Medium Frank
Moderator
 
Member#: 140114
Join Date: Feb 2007
Chapter/Region: MAIC
Location: Common Sense, VA
Vehicle:
2014 Porsche
GT3 (Currently on Fire)

Default

No, no need to be worried. Remember, you will be CLOSE to "maxing out" based on Stage 2, but doesn't mean you NEED to replace anything if you don't plan on going bigger.
HinshawWRX is offline   Reply With Quote
Old 11-16-2012, 07:28 AM   #10
tunertype
Scooby Newbie
 
Member#: 335033
Join Date: Oct 2012
Chapter/Region: NESIC
Location: Holyoke, MA
Vehicle:
2009 wrx
Dark Gray Metallic

Default

at stage 2 your injectors at 95% can provide all the fuel you need. with the intercooler you might be able to push alittle more boost and could get to around 100% IDC. your car will run like this fine until the injector gives up.(think how long a stalled drill will last if you keep giving it power... about 1 minutes and then burn fire death). Anything over 80% hurts the injectors reliability, but upgrading injectors when your at 95% will net you 0hp gain only increased reliability.

i would upgrade the injectors if its a DD. if its a weekend or track car keep stock injectors. also you really don't need to upgrade the fuel pump, but most do when getting injectors at $80 its cheap insurance. and you don't need to go crazy 650cc would be plenty. also if your cheap you can get a fpr and your 560cc can flow 605cc @50psi.
tunertype is offline   Reply With Quote
Old 11-16-2012, 09:05 AM   #11
Leafy
Scooby Specialist
 
Member#: 330625
Join Date: Aug 2012
Chapter/Region: NESIC
Location: MA
Vehicle:
2006 WRX
WRB

Default

Quote:
Originally Posted by tunertype View Post
Anything over 80% hurts the injectors reliability, but upgrading injectors when your at 95% will net you 0hp gain only increased reliability.
I wouldn't quite say that. Some big race engine shops like Rebello believe that when the fuel injector is open you are blocking a little bit of air flow, ie a long injector duty cycle hurts power. HOWEVER, I also have never seen any data for or against this theory.

Another thing that could explain why their theory is caused; since you're maxing out the injectors to hit you targeted afr you could have very different afrs on different cylinders just from the manufacturing tolerances of the injectors, which would effect power. This does happen.
Leafy is offline   Reply With Quote
Old 11-16-2012, 09:38 AM   #12
thisisntjared
Scooby Specialist
 
Member#: 177891
Join Date: Apr 2008
Chapter/Region: Tri-State
Location: south jersey
Vehicle:
06 wrx wagon
child seat/tow hitch cgm

Default

Quote:
Originally Posted by tunertype View Post
i would upgrade the injectors if its a DD. if its a weekend or track car keep stock injectors.
this only makes sense at surface value where daily drivers must be reliable and track cars may be as rigorously required to be reliable. a daily driver is floored to redline occasionally. a track car is floored to redline at every given opportunity. so which is going to push the injectors harder?

anyway, an OTS stage 2 map should not require any fueling upgrades. i know its a different car, but i ran the cobb ots stage 2 map on stock fueling for 2 years with no problems and complete peace of mind.
thisisntjared is offline   Reply With Quote
Old 11-16-2012, 09:40 AM   #13
Leafy
Scooby Specialist
 
Member#: 330625
Join Date: Aug 2012
Chapter/Region: NESIC
Location: MA
Vehicle:
2006 WRX
WRB

Default

Quote:
Originally Posted by thisisntjared View Post
this only makes sense at surface value where daily drivers must be reliable and track cars may be as rigorously required to be reliable. a daily driver is floored to redline occasionally. a track car is floored to redline at every given opportunity. so which is going to push the injectors harder?
On the flip side, which one ****s you more if it breaks? Race car you just winch back onto the trailer, daily you ride your bike to work.
Leafy is offline   Reply With Quote
Old 11-16-2012, 12:23 PM   #14
Dave D.
Scooby Specialist
 
Member#: 130990
Join Date: Nov 2006
Chapter/Region: NWIC
Location: Menzel Lake, WA
Vehicle:
06 Red Ltd.Wagon
I need a new tuner!

Default

If you are going to go bigger on the injectors, I'd recommend something that will also support a larger turbo -- I'd say 750 at least. If you go, say 20g or more in the future 750 may even fall a bit short. No point in replacing injectors twice, IMO.

But I also think you don't need bigger injectors for what you are planning to do.

(Speaking from experience. My hta68 was starting to max out my 725's -- now running 1000's.)

Last edited by Dave D.; 11-16-2012 at 02:46 PM.
Dave D. is offline   Reply With Quote
Old 11-16-2012, 02:42 PM   #15
thisisntjared
Scooby Specialist
 
Member#: 177891
Join Date: Apr 2008
Chapter/Region: Tri-State
Location: south jersey
Vehicle:
06 wrx wagon
child seat/tow hitch cgm

Default

Quote:
Originally Posted by Leafy View Post
On the flip side, which one ****s you more if it breaks? Race car you just winch back onto the trailer, daily you ride your bike to work.
no you just rent a car. both suck, just one environment increases your probability of disaster.
thisisntjared is offline   Reply With Quote
Old 11-16-2012, 06:29 PM   #16
JBones81
Scooby Newbie
 
Member#: 304046
Join Date: Dec 2011
Location: NorCal
Vehicle:
2013 BMW 335i
blue

Default

this is my daily driver...I just want the most power I can get without really affecting reliability.

My last car was an 08 c6 corvette, (actually, last car was an 03 SRT-4...but it sucked) and I was able to find a great balance between power and reliabilty by doing all the intake/exhaust mods and a tune. The car ran great, (11.6@123mph, 32mpg on the freeway) and nothing broke. I know this car won't be deep into the 11s with bolt ons, but like I said, as much as possible without hurting the car is all i'm going for here.

thanks guys,
JBones81 is offline   Reply With Quote
Old 11-16-2012, 06:38 PM   #17
06sc0obySTI
Scooby Newbie
 
Member#: 337620
Join Date: Nov 2012
Chapter/Region: Tri-State
Location: new jersey
Vehicle:
02 wrx
world rally blue

Default

not really needed but def think about bigger injectors and fuel pump in the near future. im running 1000cc injectors which is a little OD but whatever and a walboro 255 fuel pump which is working great for me
06sc0obySTI 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 11:01 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.