PCM Diagnostics & Tuning HP Tuners | Holley | Diablo
Sponsored by:
Sponsored by:

tuning for wet nitrous

Thread Tools
 
Search this Thread
 
Old 08-27-2009, 05:42 PM
  #1  
Staging Lane
Thread Starter
 
TheInferno's Avatar
 
Join Date: Aug 2007
Posts: 57
Likes: 0
Received 0 Likes on 0 Posts
Question tuning for wet nitrous

I was told that with a good tune n/a once i spray a 100 shot the computer is able to pick up the extra load, cylinder density, or whatever i forget what he said. Is this true? and how does it calculate it, its a wet kit so im not spraying tthrough the maf. Or is it best to use the resistor trick? I cant really find a clear answer and idk know anything about how the GM PCM works
Old 08-27-2009, 10:24 PM
  #2  
TECH Veteran
iTrader: (1)
 
gametech's Avatar
 
Join Date: Sep 2004
Location: Stockbridge GA
Posts: 4,214
Likes: 0
Received 532 Likes on 376 Posts
LS1Tech 20 Year Member
Default

If you run a wet shot it bypasses the computer. Dry shots can be read by the MAF until it maxes, but wet shots are a different story. The only way to safely run a wet shot is with a separate tune, tricking the timing, or running a higher octane fuel that supresses detonation under the extra load.
Old 08-27-2009, 11:02 PM
  #3  
TECH Junkie
iTrader: (33)
 
JonCR96Z's Avatar
 
Join Date: Jan 2003
Location: Asheboro, NC
Posts: 3,005
Likes: 0
Received 18 Likes on 10 Posts

Default

As long as your timing isn't crazy high and your AFR is dialed in good on motor, then you'll be fine to just spray 100 shot. Tune the nitrous fueling with the jets.
Old 08-27-2009, 11:03 PM
  #4  
TECH Fanatic
iTrader: (11)
 
SkullV's Avatar
 
Join Date: Feb 2008
Posts: 1,168
Likes: 0
Received 0 Likes on 0 Posts
Default

You basically tune for max NA power and then pull roughly 2* of timing for every 50hp of nitrous increase. If you want an EXCELLENT and simple to use timing tuner that is only active when the system is actually spraying (giving you full timing up until the point of spray and after) check out the Harris Speed Works Interface. It also works great with their "all in one" nitrous controller the MicroEdge.
Old 08-28-2009, 12:45 AM
  #5  
11 Second Club
 
5.7 ute's Avatar
 
Join Date: Oct 2006
Posts: 149
Likes: 0
Received 0 Likes on 0 Posts
Default

Or you can use a COS in Efilive, earth a pin in the PCM when the nitrous is spraying, and pull timing from the custom timing table.
Old 08-28-2009, 03:39 AM
  #6  
TECH Fanatic
iTrader: (3)
 
JDMC5's Avatar
 
Join Date: Feb 2009
Location: Highland, MI
Posts: 1,366
Likes: 0
Received 0 Likes on 0 Posts

Default

The computer will not know there is nitrous being sprayed. I ran a similar setup with my vette except I was running a 150 shot. What I did was tune the engine for n/a, then tune the fuel jet for the nitrous. The timing is a different story. It will not know to pull timing. You have 3 options. ONE: You'll have to pull timing (about 4 degrees) and run it like that all the time. TWO: flash the computer with 4 less degrees when you know you are going to spray. THREE: run a separate timing "tricker" to pull timing when the nitrous is engaged. When I say -4 degrees that is based on an optimum max timing for n/a minus 4. For example, I ran a max of 29 degrees timing n/a on my vette. When I sprayed I pulled timing to about 25 degrees max. I had an integrated iat/ maf sensor so I couldn't run a resistor mod. As far as I can remember all F-bodies run a separate iat sensor so the resistor mod is an option for you. Then again if you are running stock timing you should be fine as far as timing goes because I think the computer (besides the 98 model) only runs about 25 degrees total. PM me if you would like to know more.
Old 08-29-2009, 05:49 PM
  #7  
11 Second Club
 
Dragman's Avatar
 
Join Date: May 2004
Location: Ky
Posts: 528
Likes: 0
Received 0 Likes on 0 Posts

Default

I also run a 150 wet kit. I run -6 degree's and load program when I spray. I tune my AFR with VE table & run open loop SD. Seams to be a better way for me to get my AFR tuned closer to what I want than changing fuel jets.
Old 08-29-2009, 05:58 PM
  #8  
Staging Lane
Thread Starter
 
TheInferno's Avatar
 
Join Date: Aug 2007
Posts: 57
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Dragman
I also run a 150 wet kit. I run -6 degree's and load program when I spray. I tune my AFR with VE table & run open loop SD. Seams to be a better way for me to get my AFR tuned closer to what I want than changing fuel jets.
so you also use load to pull the timing, correct. im going to have i tuned as if i didnt have spray and get as close as i can with the jets and do fine tuning as you did yours.
Old 08-29-2009, 06:11 PM
  #9  
Banned
 
2Tightwads's Avatar
 
Join Date: Jun 2009
Location: San Antonio, TX
Posts: 42
Likes: 0
Received 0 Likes on 0 Posts
Talking

Originally Posted by SkullV
You basically tune for max NA power and then pull roughly 2* of timing for every 50hp of nitrous increase. If you want an EXCELLENT and simple to use timing tuner that is only active when the system is actually spraying (giving you full timing up until the point of spray and after) check out the Harris Speed Works Interface. It also works great with their "all in one" nitrous controller the MicroEdge.
Excellent answer with referal, nice!
Old 08-29-2009, 07:12 PM
  #10  
TECH Fanatic
iTrader: (3)
 
JDMC5's Avatar
 
Join Date: Feb 2009
Location: Highland, MI
Posts: 1,366
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by TheInferno
so you also use load to pull the timing, correct. im going to have i tuned as if i didnt have spray and get as close as i can with the jets and do fine tuning as you did yours.
You can't do that with a wet kit only a dry kit. The engine has no way of knowing there is extra air entering hence the nitrous AND fuel being sprayed, because the maf is bypassed. The dry kit measures the extra load by spraying through the maf, people log the load tables used when spraying and pull timing in those tables. You need to do a resister mod to the IAT that comes on when the nitrous unit is powered up.

Last edited by JDMC5; 08-30-2009 at 02:57 AM. Reason: I was being kind of a dick



Quick Reply: tuning for wet nitrous



All times are GMT -5. The time now is 07:01 AM.