2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Who thinks 12 psi is too much for stock injectors?

Old Dec 8, 2002 | 11:02 PM
  #1  
Bambam7's Avatar
Thread Starter
I came, I saw, I boosted.
Tenured Member 10 Years
 
Joined: Apr 2001
Posts: 1,921
Likes: 0
From: Windsor, Ontario, Canada
Who thinks 12 psi is too much for stock injectors?

Hi... OK, The turbo NA is running well.... but I am not getting enough fuel.
1st and second gear are fine, getting only to 8-9 psi.
3rd hits about 10 psi, but 4th gear goes to 12+
It keeps pinging a bit around 5500 rpms (so I let off immediately of course), there is a lean spot (goes up to around 13:1)
This is on my high-comp S5 N/A rotors too! Not cool. I want around 11:1 at most
Anyways, I can set my S-AFC to full (50% more) rich at 5000, and it doesn't get any richer.... the 12 psi is definatly too much for the stock TII fuel system, I guess 9 psi is about the limit.
Question is... is it the fuel pump or the injectors that need to be upgraded??
Reply
Old Dec 8, 2002 | 11:52 PM
  #2  
No7Yet's Avatar
Rotary Enthusiast
Tenured Member 10 Years
 
Joined: Aug 2001
Posts: 1,402
Likes: 0
From: Tallahassee, FL
Both.

Brandon
Reply
Old Dec 8, 2002 | 11:54 PM
  #3  
dr0x's Avatar
pei > caek
Tenured Member 05 Years
 
Joined: May 2002
Posts: 4,643
Likes: 0
From: Mars
Id say both, but if you are strapped for cash right now get a good pump and stay away from boost
Reply
Old Dec 9, 2002 | 12:07 AM
  #4  
Scott 89t2's Avatar
SOLD THE RX-7!
Tenured Member 10 Years
 
Joined: Mar 2001
Posts: 7,451
Likes: 0
From: Vancouver, BC, Canada
what pump are you using?? please don't say the N/A pump?!?! that flows 1/2 as much as the turbo pump flows. and the turbo one is barly enough.

what ecu? turbo or N/A ? if N/A you probbaly have way to much timming.

13 is way too lean. should be 11.7:1 or so.

stock injectors are good for 12psi or 280hp or so.

I asume you are running 94 oct? or the highest in your area?
Reply
Old Dec 9, 2002 | 12:15 AM
  #5  
j9fd3s's Avatar
Moderator
Community Builder
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Mar 2001
Posts: 31,837
Likes: 3,234
From: https://www2.mazda.com/en/100th/
you can also bypass the fuel pressure regulator solenoid, that will give you a little more fuel under boost

mike
Reply
Old Dec 9, 2002 | 12:27 AM
  #6  
Bambam7's Avatar
Thread Starter
I came, I saw, I boosted.
Tenured Member 10 Years
 
Joined: Apr 2001
Posts: 1,921
Likes: 0
From: Windsor, Ontario, Canada
I am running a TII pump. I thought that this, with the 4 550's would be enough.. I guess not!
I havn't rewired the pump yet, using a direct battery connection, and a relay. I will do that ASAP.

I have backed the timing off about 3-4 degrees. (N/A ECU) If I back it off any more it KILLS power under 2000 rpms.


Well, I'll probably rewire, and then just wrap some duct tape around the air filter to keep things in check untill I get an FD pump and some 720's or something.....

Thanks for the input!
Reply
Old Dec 9, 2002 | 01:09 AM
  #7  
Scott 89t2's Avatar
SOLD THE RX-7!
Tenured Member 10 Years
 
Joined: Mar 2001
Posts: 7,451
Likes: 0
From: Vancouver, BC, Canada
oh ya you are probably running the N/A FPR right??? you are missing 10 psi of fuel pressure at 10psi boost!! so you are running around 20% less fuel then a TII would at 10psi...
the stock TII FPR increases FP 1 psi for every psi of boost.
Reply
Old Dec 9, 2002 | 01:12 AM
  #8  
Scott 89t2's Avatar
SOLD THE RX-7!
Tenured Member 10 Years
 
Joined: Mar 2001
Posts: 7,451
Likes: 0
From: Vancouver, BC, Canada
Originally posted by Bambam7

I have backed the timing off about 3-4 degrees. (N/A ECU) If I back it off any more it KILLS power under 2000 rpms.

well.... that's why you don't turbo an N/A turbo or standalone ECU will give timming at the low end, while retarding the top end
Reply
Old Dec 11, 2002 | 02:03 AM
  #9  
NZConvertible's Avatar
I'm a boost creep...
Tenured Member 05 Years
 
Joined: Jan 2002
Posts: 15,608
Likes: 8
From: Auckland, New Zealand
Originally posted by j9fd3s
you can also bypass the fuel pressure regulator solenoid, that will give you a little more fuel under boost
No it won't! Please don't dish out info about systems you don't understand the workings of.
Reply
Old Dec 11, 2002 | 08:34 AM
  #10  
adamlewis's Avatar
Back from teh deadly!
Tenured Member 20 Years
 
Joined: Feb 2001
Posts: 1,163
Likes: 0
From: Louisville KY 40299
Originally posted by NZConvertible
No it won't! Please don't dish out info about systems you don't understand the workings of.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
Jul 1, 2023 04:40 PM
dkwasherexd
Single Turbo RX-7's
21
May 27, 2017 04:51 AM
armans
3rd Generation Specific (1993-2002)
5
Aug 15, 2015 09:08 PM
Snook
3rd Generation Specific (1993-2002)
12
Aug 15, 2015 08:18 AM
RCCAZ 1
1st Generation Specific (1979-1985)
5
Aug 11, 2015 07:05 PM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 11:24 AM.