Notices
Engine Management and ECU Remapping This section is to discuss the various aspects of engine management modification for your Subaru.

Surging in 4th and 5th WOT

Thread Tools
 
Search this Thread
 
Old 20 May 2023, 09:56 PM
  #1  
Raw2686
Scooby Newbie
Thread Starter
 
Raw2686's Avatar
 
Join Date: May 2023
Location: Burntwood
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default Surging in 4th and 5th WOT

Hi all, recently brought a WRX with mods, FMIC pink injectors, VF35, decatted, uprated fuel pump and ECUtek remap to 336bhp.
The issue I’m facing is in 4th and 5th the car seems to surge/lunge when wot, if I feather the throttle it drives nice but any more than half I get this problem? I’ve done some bits with no joy, only other thing to note is I’m getting a random misfire codes cylinder 2 and 4 but I’m led to believe this is due to a billet flywheel?
any advice welcomed!
Old 20 May 2023, 11:41 PM
  #2  
JDM_Stig
Scooby Regular
iTrader: (3)
 
JDM_Stig's Avatar
 
Join Date: Feb 2009
Location: Mount Weather
Posts: 5,840
Received 41 Likes on 33 Posts
Default

Time to log whats actually happening, boost/fuelling etc.
Old 21 May 2023, 10:53 AM
  #3  
Raw2686
Scooby Newbie
Thread Starter
 
Raw2686's Avatar
 
Join Date: May 2023
Location: Burntwood
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default

I’m trying to get SSM working or looking at a dyno/diag run. I’m looking at changing my intake pipe as it’s a silicone Perrin one, when the problem happens I make 1.1bar of boost and the surge happens​​​​​​… first and second ok it sometimes happens in third if going up a steep hill?
Old 19 October 2023, 10:22 PM
  #4  
vulnax999
Scooby Senior
Support Scoobynet!
iTrader: (7)
 
vulnax999's Avatar
 
Join Date: May 2003
Posts: 4,347
Received 8 Likes on 7 Posts
Default

Overboosting mate, bad mapping or dodgy boost solenoid, or all those mods make the car too good!
The silicone intake pipes are known to collapse on good boost / high suck ... not sure if Perrin do or do not! ( I have a fair few bits of Perrin on my Scooby ).

Could be a simple boost solenoid hose has come off? So too much boost when booted?

Won't be due to a billet flywheel as that would only cause poor starts / pull away, requiring a slightly higher idle or more throttle on pulling away.

Suggest go back / go to a reputable Subaru mapper and get them to look at the surge problem.


Don't expect you to have equipment to log the engine parameters as suggested above so will need a Subaru specialist or auto electrician or similar.


Last edited by vulnax999; 19 October 2023 at 10:23 PM.
Old 28 October 2023, 06:40 AM
  #5  
Raw2686
Scooby Newbie
Thread Starter
 
Raw2686's Avatar
 
Join Date: May 2023
Location: Burntwood
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default

Hi thanks for the reply.
I have changed the boost solenoid and this sorted the low boost I was experiencing at first.

I have read up that with the VF35 and FMIC they are prone to surge, on one of the forums it suggests the intake pipe diameter to large, I changed the intake for a different silicon one and it’s much better.
ill see if I can find the link.
Old 28 October 2023, 06:50 AM
  #6  
Raw2686
Scooby Newbie
Thread Starter
 
Raw2686's Avatar
 
Join Date: May 2023
Location: Burntwood
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default

https://www.scoobynet.com/general-te...t-problem.html

here’s the thread and its pretty much the same as what I’m experiencing, I have brought a std intake pipe, just need to fit.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
physical
General Technical
9
13 February 2015 09:27 AM
snakecharmer
General Technical
3
19 May 2011 08:25 PM
Semper
General Technical
68
14 April 2009 09:57 AM
stewgb270
General Technical
4
15 February 2009 09:30 AM
ESH
General Technical
15
12 September 2006 11:24 AM



Quick Reply: Surging in 4th and 5th WOT



All times are GMT +1. The time now is 10:06 AM.