Car went bad lean on dry shot???
I didn't want to multi quote everyone, so will sum it up. Most gave excellent advice. For the most part, yes a nozzle close will give a better reading and thus be able to add the fuel needed. The problem with it being so far away, along with what Beer said on diluted reading, is air dynamics start to play a role (Dyno tune was correct on being close and missing MAF wires, but this happens, due to air dynamics, very, very seldom up close). Meaning, your n2o can be swept totally past, or around the MAF wires and give no additional cold reading. Nozzle tuning can work great, however, the key to good dry a/f tuning now is to use the HSW "Interface". This product is the absolute bomb for dialing in the a/f ratio on dry hits as well as wet hits, and has the benefit of timing pull, a great investment IMO. Also, this allows for optimum n/a tune. The reason you didn't hurt anything when hitting a 17.x:1 a/f ratio is the simple fact that is was a small hit and subsequent cylinder pressures were not that high. Though, a prolonged run could have hurt your motor. Good thing you didn't start out with a 250rwhp shot, and the reason we always say start small and work your way up checking all parameters as you go.
Robert
On a dry hit your going above what you see on the MAF NA.
If he had a good nozzle location, he could tune only above the NA MAF Frequencies, it really won't have any effect on the NA tune (other than the timing if pulled).
Likely based on the nozzle position, I would agree that he added fuel and unless its setup on COS 5 or other software/hardware tricks, the NA tune probably suffers a bit.
If he had a good nozzle location, he could tune only above the NA MAF Frequencies, it really won't have any effect on the NA tune (other than the timing if pulled).
Likely based on the nozzle position, I would agree that he added fuel and unless its setup on COS 5 or other software/hardware tricks, the NA tune probably suffers a bit.
Last edited by Beer99C5; Mar 9, 2008 at 02:49 PM.
Tuner is wrong, we have gone to 300rwhp shot at about 4/6 inches from MAF. Many tuners really do not understand how a dry works.
Yeppers, and pointed directly at said MAF, then some slight nozzle tuning can be done to fine tune a/f (rotating nozzle, changing style of nozzle, adding extra by pass nozzle, etc.).
Totally false, an old wives tale. If that were true, nobody could drive their cars in Chicago during the winter when temps get below zero on the freeway. Now the MAF screen can freeze due to condensation from the n2o, but we need to remove it for dry hits.
If he was able to compansate with the n/a tune, then running out of injectors hasn't happened yet, but a good point none the less.
I didn't want to multi quote everyone, so will sum it up. Most gave excellent advice. For the most part, yes a nozzle close will give a better reading and thus be able to add the fuel needed. The problem with it being so far away, along with what Beer said on diluted reading, is air dynamics start to play a role (Dyno tune was correct on being close and missing MAF wires, but this happens, due to air dynamics, very, very seldom up close). Meaning, your n2o can be swept totally past, or around the MAF wires and give no additional cold reading. Nozzle tuning can work great, however, the key to good dry a/f tuning now is to use the HSW "Interface". This product is the absolute bomb for dialing in the a/f ratio on dry hits as well as wet hits, and has the benefit of timing pull, a great investment IMO. Also, this allows for optimum n/a tune. The reason you didn't hurt anything when hitting a 17.x:1 a/f ratio is the simple fact that is was a small hit and subsequent cylinder pressures were not that high. Though, a prolonged run could have hurt your motor. Good thing you didn't start out with a 250rwhp shot, and the reason we always say start small and work your way up checking all parameters as you go.
Robert
Yeppers, and pointed directly at said MAF, then some slight nozzle tuning can be done to fine tune a/f (rotating nozzle, changing style of nozzle, adding extra by pass nozzle, etc.).
Totally false, an old wives tale. If that were true, nobody could drive their cars in Chicago during the winter when temps get below zero on the freeway. Now the MAF screen can freeze due to condensation from the n2o, but we need to remove it for dry hits.
If he was able to compansate with the n/a tune, then running out of injectors hasn't happened yet, but a good point none the less.
I didn't want to multi quote everyone, so will sum it up. Most gave excellent advice. For the most part, yes a nozzle close will give a better reading and thus be able to add the fuel needed. The problem with it being so far away, along with what Beer said on diluted reading, is air dynamics start to play a role (Dyno tune was correct on being close and missing MAF wires, but this happens, due to air dynamics, very, very seldom up close). Meaning, your n2o can be swept totally past, or around the MAF wires and give no additional cold reading. Nozzle tuning can work great, however, the key to good dry a/f tuning now is to use the HSW "Interface". This product is the absolute bomb for dialing in the a/f ratio on dry hits as well as wet hits, and has the benefit of timing pull, a great investment IMO. Also, this allows for optimum n/a tune. The reason you didn't hurt anything when hitting a 17.x:1 a/f ratio is the simple fact that is was a small hit and subsequent cylinder pressures were not that high. Though, a prolonged run could have hurt your motor. Good thing you didn't start out with a 250rwhp shot, and the reason we always say start small and work your way up checking all parameters as you go.
Robert
The man has spoken. Excellent advise robert as always. I have read and taken advise from robert on dry hits and setups back when i had one on mine and also when tweaking on buddys cars.
all advice is appreciated. Robert, does it hurt to leave the nozzle where i have it? because we have a relay setup to kick on when i arm the system and this is setup in the tune to pull the timing and add the fuel that i need while spraying, this way my NA tune doesnt suffer. so now that its tuned, i dont have to rely on the maf anymore. so my real question is what is best for performance, closer to the maf or farther?
all advice is appreciated. Robert, does it hurt to leave the nozzle where i have it? because we have a relay setup to kick on when i arm the system and this is setup in the tune to pull the timing and add the fuel that i need while spraying, this way my NA tune doesnt suffer. so now that its tuned, i dont have to rely on the maf anymore. so my real question is what is best for performance, closer to the maf or farther?
Robert
It's hard for me to say things are absolutely fine. If you see that your a/f is fine when spraying, then yes you can leave things alone. However, I suspect that the tuner just added to your WOT Power Enrichment multiplier and this will cause the n/a tune to run rich at WOT. Not really a big deal, other than missing a few n/a ponies from over rich. But then again, he may have done something totally different, so if ya trust him, you'll be fine. The relay could be connected to a resistor that fools another look up table that the boost guys use, IAT vs Fuel Multiplier. This way you can add an additional multiplier on top of the standard N/A multiplier and only comes into effect when spraying. I have messed with this way myself.
Robert
Robert
and stay off my thread if you arent adding useful info.