Dry Shot Harmful to Stock Engine?
Oct 12, 2004 | 07:33 PM
#31
TECH Junkie
Joined: Mar 2003
Posts: 3,271
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From: Katy, TX
Originally Posted by 02denali
i think some were experiencing a slight freezing of the screen when it was to close to the maf. as far as detonation. there will always be some you cant hear. i am running a 150 shot. i keep tabs on my fuel and kr. the tranny will go first. just be cool with it and you will be ok.
Now its been on for almost a year and a half and still runnin strong. To strong for traction and any real times.
(12.89@115.9)
Oct 12, 2004 | 08:23 PM
#32
Thread Starter
TECH Fanatic
Joined: May 2004
Posts: 1,087
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From: Cibolo Tx
Originally Posted by oxidizr
Some basic info on nitrous....
Wet = nitrous+fuel introduced after any air metering devise such as a MAF via nozzles or spray bars.
Dry = nitrous introduced without fuel.
Dry nitrous CAN be introduced before or after the air meter (MAF) so long as the system is designed to function that way.
Dry nitrous before the MAF. In this case the nitrous is injected in a fashion such that the MAF is use to determine proper fueling. (see below for basic explanation of how a MAF works) The MAF reads the change in intake charge temp. It uses that data to determin changes in air desity and thus changes in combustable air. Lower temp = more density = more air = more fuel.
Dry nitrous after the MAF. In this case the nitrous is injected in a manor that does not require the air meter to compensate. In most cases, engine vaccum or tps is used to actuate a fuel boosting system. On a bypassing fuel system the vacuum circuit is usually controlling the fuel pressure regulator and under WOT boosts fuel pressure to a determined value to match nitrous flow. Some systems use tps and o2 readings to activate higher injector cycle time. In either case the injectors are directly influenced into flowing more fuel outside of the air meter's reading.
MAF location
I tend to get my best result wit about 8-12 inches of space between the MAF and fanspray. Distance will not be same in all applications as diameter of the intake and number of bends and fanspray location do play a role.
How much dry nitrous is too much?
Depends on your particular set-up .. many variables to consider ranging from state of motor build to converter size to fuel system stability. I have run 175 HP dry without any failure but watching fuel showed a noticable change in pressure (3-5 psi) and i had to let out.
Just some info ...
How a MAF works
The MAF consists of a heated element and it uses a constant to determine airflow relatie to voltage change. As more air travels across it the element cools and a change in voltage is registered the amount of energy require to heat or reheat the element. The amount of air passing over this element and how much it cools the element is directly corolated to the total air volume taken in. In the case of nitrous use the super cool -273* discharge will cool the element and so much that the MAF adds adequate fueling to support the nitrous being injected.
Richard
Wet = nitrous+fuel introduced after any air metering devise such as a MAF via nozzles or spray bars.
Dry = nitrous introduced without fuel.
Dry nitrous CAN be introduced before or after the air meter (MAF) so long as the system is designed to function that way.
Dry nitrous before the MAF. In this case the nitrous is injected in a fashion such that the MAF is use to determine proper fueling. (see below for basic explanation of how a MAF works) The MAF reads the change in intake charge temp. It uses that data to determin changes in air desity and thus changes in combustable air. Lower temp = more density = more air = more fuel.
Dry nitrous after the MAF. In this case the nitrous is injected in a manor that does not require the air meter to compensate. In most cases, engine vaccum or tps is used to actuate a fuel boosting system. On a bypassing fuel system the vacuum circuit is usually controlling the fuel pressure regulator and under WOT boosts fuel pressure to a determined value to match nitrous flow. Some systems use tps and o2 readings to activate higher injector cycle time. In either case the injectors are directly influenced into flowing more fuel outside of the air meter's reading.
MAF location
I tend to get my best result wit about 8-12 inches of space between the MAF and fanspray. Distance will not be same in all applications as diameter of the intake and number of bends and fanspray location do play a role.
How much dry nitrous is too much?
Depends on your particular set-up .. many variables to consider ranging from state of motor build to converter size to fuel system stability. I have run 175 HP dry without any failure but watching fuel showed a noticable change in pressure (3-5 psi) and i had to let out.
Just some info ...
How a MAF works
The MAF consists of a heated element and it uses a constant to determine airflow relatie to voltage change. As more air travels across it the element cools and a change in voltage is registered the amount of energy require to heat or reheat the element. The amount of air passing over this element and how much it cools the element is directly corolated to the total air volume taken in. In the case of nitrous use the super cool -273* discharge will cool the element and so much that the MAF adds adequate fueling to support the nitrous being injected.
Richard
Oct 12, 2004 | 09:06 PM
#33
Originally Posted by shandy294
What about timing retard since MAF can take care of adding more fuel? Need another system to handle timing?
Richard
Oct 12, 2004 | 10:36 PM
#35
Originally Posted by bigbody
Hey BigKID, I was wondering if you had any pics. of how your dry shot was setup. I would like to know how I should set mine up so I can spray before the MAF. Cause I would rather do it the safe way like you.
Did you leave the whole intake on there an just place the N20 nozzle infront of the MAF?
Did you leave the whole intake on there an just place the N20 nozzle infront of the MAF?
Oct 13, 2004 | 12:55 AM
#36
On The Tree
Joined: Apr 2004
Posts: 125
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OK, so if I keep my same Nelson tune in my truck for now, then I install the Nitrous before the MAF, an I only spray a 100 shot max. Will that be ok? Or would I still have to have Nelson retard the timing still? Cause I dont want to take away 4* of timing, cause I will only spray a few times. My truck is a every day driver as of now, so I dont want to losse any of my natural perfomance from retarding the timeing. You know what I mean.
Oct 13, 2004 | 01:10 AM
#37
TECH Resident
Joined: Sep 2004
Posts: 796
Likes: 11
From: Cali
Good info from Oxidizr....
If you already have a Nelson Tune... send it back.... have him update it for FREE... why not?? tell him you are adding a 100 dry shot and he'll set you up Right.
Now I have a question... is it Necessary to REMOVE the Maf screen when spraying a dry shot before the MAF? I have heard that you can freeze up the maf alot easier if you don't take the screen out... is this true??
here is my current intake setup....
I plan on putting the fogger in the tip of the filter... will this be too close to the MAF??? I think I might be pushing it to the edge, so I might end up moving it near the throttle body for the 100 shot... any suggestions???
If you already have a Nelson Tune... send it back.... have him update it for FREE... why not?? tell him you are adding a 100 dry shot and he'll set you up Right.
Now I have a question... is it Necessary to REMOVE the Maf screen when spraying a dry shot before the MAF? I have heard that you can freeze up the maf alot easier if you don't take the screen out... is this true??
here is my current intake setup....
I plan on putting the fogger in the tip of the filter... will this be too close to the MAF??? I think I might be pushing it to the edge, so I might end up moving it near the throttle body for the 100 shot... any suggestions???
Then you can move your MAF closer to the TB alot easier and not have to worry about freezing it over.
Oct 13, 2004 | 03:13 AM
#39
TECH Resident
Joined: Sep 2004
Posts: 796
Likes: 11
From: Cali
thought about that, but i already have too many things on the list as it is..... dont we all..
It would be easy to do with more room there for sure. Do you think there is an optimal place for the MAF?.. or further away from the nozzle the better. i'd think about 8-14" would be about perfect, but I guess it depends on the jet size and which way it sprays.. Some setups have two jets pointed in and others have say one pointing up the intake tube. I wonder if a certain setup has proved to have better read outs and performance with a dry shot..??
It would be easy to do with more room there for sure. Do you think there is an optimal place for the MAF?.. or further away from the nozzle the better. i'd think about 8-14" would be about perfect, but I guess it depends on the jet size and which way it sprays.. Some setups have two jets pointed in and others have say one pointing up the intake tube. I wonder if a certain setup has proved to have better read outs and performance with a dry shot..??
Oct 13, 2004 | 10:54 PM
#40
Teching In
Joined: Jun 2004
Posts: 5
Likes: 0
From: Alvin
I know you guys might be right on the whole spraying before the MAF thing. But my friend has been spraying a 100 dry shot right infront of the throttle body for like 2 years now. An his struck is still running great. I thought it would of messed up something by now. An he never even hears an denotaton either. So I dont really know what to say.
