G35 Coupe V35 2003 - 07 Discussion about the 1st Generation V35 G35 Coupe

Fuel system upgrade

  #1  
Old 05-11-2019, 10:14 AM
Registered User
Thread Starter
Join Date: May 2019
Posts: 16
Received 0 Likes on 0 Posts
G35 sedan built short block
Fuel system upgrade

I have a question about upgrading fuel system. I am building a FI project. The short block is built with forged pistons and rods. I want to get a high flow pump, return system kit and high flow injectors. My question is do I need to have it tuned with this upgrade, or can the stock ecu adjust for the difference? I will be adding high flow cats and a spacer soon and donít want to run lean.
 
  #2  
Old 05-11-2019, 10:49 AM
cleric670@gmail's Avatar
BANNED!!!
Join Date: May 2017
Location: Washington State
Posts: 7,018
Received 822 Likes on 756 Posts
Coupe 6MT Premium RAS
You will definitely need a tune unless by some miracle the flow rate of the injectors is perfectly matched to what the forced induction setup will consume, technically it's mathematically POSSIBLE but I've never seen it happen.

Most tuners can give you a baseline tune that will get the car to start so you can check for leaks and stuff, but you should throw the car on a flatbed and tow it to the tuner unless you can drive at low speed with low throttle down to the shop.

You can always watch A/F yourself via OBD2.
 
  #3  
Old 05-11-2019, 11:33 AM
Registered User
Thread Starter
Join Date: May 2019
Posts: 16
Received 0 Likes on 0 Posts
G35 sedan built short block
Ok thanks

[[email protected];7167700]You will definitely need a tune unless by some miracle the flow rate of the injectors is perfectly matched to what the forced induction setup will consume, technically it's mathematically POSSIBLE but I've never seen it happen.

Most tuners can give you a baseline tune that will get the car to start so you can check for leaks and stuff, but you should throw the car on a flatbed and tow it to the tuner unless you can drive at low speed with low throttle down to the shop.

You can always watch A/F yourself via OBD2.
Ok just curious I do have a scanner and can watch short term and long term. I donít want to have to pay for tuning until I have all my mods done. I plan on driving it daily while I am building it.
 
  #4  
Old 05-11-2019, 12:02 PM
cleric670@gmail's Avatar
BANNED!!!
Join Date: May 2017
Location: Washington State
Posts: 7,018
Received 822 Likes on 756 Posts
Coupe 6MT Premium RAS
You're probably fine with the spacer and cats. When you start to mess with FI, injectors, pumps, etc then you'll definitely need a tune.
 
  #5  
Old 05-11-2019, 01:50 PM
LoSt180's Avatar
Premier Member
iTrader: (11)
Join Date: Mar 2011
Location: Maryland
Posts: 2,680
Received 419 Likes on 344 Posts
You will absolutely need a tune if you change injector size. The car is tuned for a specific flow rate, and opens the injectors a specific amount of time. Larger injectors will dump more fuel for the same amount of time open. The ecu can't compensate for such a change and will just throw codes while your car is running stupidly rich.

Change everything at once, then get it tuned. Or work with an e-tuner that will adjust the tune whenever you change parts.
 
  #6  
Old 05-11-2019, 06:24 PM
Registered User
Thread Starter
Join Date: May 2019
Posts: 16
Received 0 Likes on 0 Posts
G35 sedan built short block
Originally Posted by LoSt180 View Post
You will absolutely need a tune if you change injector size. The car is tuned for a specific flow rate, and opens the injectors a specific amount of time. Larger injectors will dump more fuel for the same amount of time open. The ecu can't compensate for such a change and will just throw codes while your car is running stupidly rich.

Change everything at once, then get it tuned. Or work with an e-tuner that will adjust the tune whenever you change parts.
So if for now I just want to upgrade the Fuel system and do a couple mods like a spacer and high flow cats/ exhaust how much would it cost to get it tuned and how much HP do you think I could get NA
 
  #7  
Old 05-11-2019, 07:33 PM
cleric670@gmail's Avatar
BANNED!!!
Join Date: May 2017
Location: Washington State
Posts: 7,018
Received 822 Likes on 756 Posts
Coupe 6MT Premium RAS
Don't do the fuel system changes, save them until you're ready to install the FI. The rest of those mods (spacer, hfc, exhaust, tune) will net you about 40whp. Stock injectors and pump are more than capable of handling delivery of those mods.
 
  #8  
Old 05-11-2019, 08:50 PM
LoSt180's Avatar
Premier Member
iTrader: (11)
Join Date: Mar 2011
Location: Maryland
Posts: 2,680
Received 419 Likes on 344 Posts
^^^ what he said.

PM member seymore4 on here about a tune. Basic Uprev tune should run about $500. He'll give you specifics though, I'm just ball parking it.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
iTzTeddy
Engine, Drivetrain & Forced-Induction
2
04-13-2016 06:18 PM
350z006
Engine - Intake/Fuel
5
06-08-2012 01:18 PM
godmans
Engine, Drivetrain & Forced-Induction
7
03-19-2007 10:20 AM


Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: Fuel system upgrade


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: