3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

Interesting boost pattern issue

Thread Tools
 
Search this Thread
 
Old 03-22-09, 11:52 AM
  #1  
Full Member
Thread Starter
 
Integrals's Avatar
 
Join Date: Aug 2007
Location: Arizona
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
Interesting boost pattern issue

Ok so i've searched and tried to find someone having a similar problem to help narrow down the solution but have failed thus far. Anyone who can point me at the right system woudl be very appreciated.

Basically speaking, my car will hit 10psi on primary, and will go to 8psi and back to 10psi when the secondary comes online. Great right?

Ok the problem is if the car is running 3psi, and hits 4k, the psi will drop, and then you can hear the secondary turbine come online and the boost starts to build again.

Cliff notes: Secondary turbine is coming online without the primary getting a full 10psi.
Car has a normal 10 8 10 boost pattern when WOT


Help? lol
Old 03-22-09, 12:58 PM
  #2  
Moderator

iTrader: (7)
 
dgeesaman's Avatar
 
Join Date: May 2002
Location: Fort Kickass
Posts: 12,302
Received 16 Likes on 15 Posts
Have you replaced the check valves? I would start with that.
Old 03-22-09, 02:27 PM
  #3  
Full Member
Thread Starter
 
Integrals's Avatar
 
Join Date: Aug 2007
Location: Arizona
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
Yeah all were replaced with the VITON valves and lines, and i've checked directionality of them. Im well familiar with the issue of the turbines not going back to sequential and running parallel if a check valves bites the dust but this seems to be even weirder lol
Old 03-22-09, 03:14 PM
  #4  
Mr. Links

iTrader: (1)
 
Mahjik's Avatar
 
Join Date: Aug 2001
Location: Kansas City, MO
Posts: 27,595
Received 40 Likes on 26 Posts
Does the boost pattern change per gear? i.e. if you floor it from 1st or 2nd gear does it not get a full 10 PSI on the first turbo (I know it happens quick)? If that happens, does it work properly flooring it from 3rd gear?
Old 03-22-09, 03:16 PM
  #5  
Full Member
Thread Starter
 
Integrals's Avatar
 
Join Date: Aug 2007
Location: Arizona
Posts: 228
Likes: 0
Received 0 Likes on 0 Posts
1st through 3rd it will hit 10 psi, then 8, then 10 again like normal.

Its just when i go like half throttle it will go 5psi, then i can HEAR the secondary turbine come online and the boost will drop 1-2psi and then go back up to 5 and climb back up to 10psi if i give it more throttle with the turbos running in parallel.
OH and the mod list is in the signature if that helps any.

Only thing not listed is it is Vmounted now.
Old 03-22-09, 03:27 PM
  #6  
Mr. Links

iTrader: (1)
 
Mahjik's Avatar
 
Join Date: Aug 2001
Location: Kansas City, MO
Posts: 27,595
Received 40 Likes on 26 Posts
Arrow

You might check this thread:

https://www.rx7club.com/3rd-gen-archives-73/weird-boost-issue-685269/
Old 03-22-09, 04:10 PM
  #7  
Super Raterhater

iTrader: (6)
 
SonicRaT's Avatar
 
Join Date: Dec 2001
Location: NY, MA, MI, OR, TX, and now LA or AZ!
Posts: 10,624
Likes: 0
Received 2 Likes on 2 Posts
That seems to be the normal behavior as the ECU doesn't seem to use feedback on the primary turbo to bring the secondary online. I have the same effect both on a PowerFC and the stock ECU, it seems to be RPM based and above a certain RPM they run non-sequential regardless of the pressure.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
C. Ludwig
Single Turbo RX-7's
49
01-30-19 06:31 AM
Queppa
New Member RX-7 Technical
8
09-02-18 09:53 AM
Jeff20B
1st Generation Specific (1979-1985)
4
06-26-16 10:21 AM



Quick Reply: Interesting boost pattern issue



All times are GMT -5. The time now is 01:33 PM.