7psi boost + N2O + WI....thoughts?

[PITBULL]

I've decided to run a nitrous/WI combo on my Vortech blown 4.0 V-6. The motor is set up for 9:1 static CR and fueling is done with larger injectors and a calibrated Mass Airflow Sensor, not a FMU.

The nitrous kit is a dry fogger, I'll probably start with a 35 shot to keep it on the safe side.

I have some questions, maybe someone has done something like this before and can help me out.

The discharge tubing from the supercharger to the intake isn't very long, 12 inches max.

What are everyone's recommendations as far as nitrous and WI nozzle placement? I know they both need to be as far away from the intake as possible for optimum mixing and distribution to the cylinders. Is it preferable to have the nitrous upstream or downstream of the WI nozzle?

I am probably going to just use about a 25% methanol to water mix to offset any freezing effect the nitrous may have....I don't think I will need the methanol for fueling since the dry nitrous kit is going to help with that.

What about timing retard? I know with WI alone I will be able to keep my timing advance with the blower...but typically nitrous users retard their timing. Any suggestions here?

Any other tuning tips you guys have on blower/nitrous combinations or nitrous/WI setups would really be appreciated.

Thanks!

[StiScoobySnacks.]

Don't use a dry nitrous kit. there bad for your motor. the dry kit works by sprying nitrous into you intake and adds fuel through your injectors. the nitrous will not flow evenly to each cylinder, this will make some cylinders run rich and some the run lean. if you use a wet kit, the kit will spry nitrous and fuel into you intake. the mixture of nitrous and fuel will flow together into the motor evenly. if you want the best and safest way the use nitrous get a direct port wet kit, the kit works by sprying nitrous and fuel evenly into you intake maniflod.

[Rootzz06]

Scooby has some good points about uneven distrobution but I have seen alot of people run the dry kits at low HP levels without any problem.One thing I can tell you is that the GM MAF FI system guys put the dry nozzle kits in thier airbox,before the MAF.I think that if you use a dry shot after the MAF the computer may not adjust for the added oxygen.I dont know if the MAF or the oxygen sensors or both are what adjusts the AFR when using a dry shot."my theory"using methanol in your WI system can also be a way of adding extra fuel/detonation suppression for your nitrous shot.a week ago I completed my first WI and nitrous install (wet kit) so I am learning and tuning still.

[PITBULL]

My application uses speed density (MAP) so tricking the MAF won't really work for me. My dry kit adds fuel by spiking the fuel pressure (an adjustable feature) so it forces more fuel through the injectors. It's a little on the rich side so I may reduce the amount of fuel pressure it adds when incorporating WI. Fuel flow volume shouldn't be a problem since I'm running a 190lph in-tank and a 155lph in line fuel pumps.

[Rootzz06]

That sounds cool Pitbull--I have installed a wet system but havent tried it out yet.I probably could have used a dry setup.My AFR is at 12.5 WOT.without the NOS.If you are running rich then you dont need any more fuel.I guess you have experience with your setup already so I'll ask you a question---do you have to retard timing or did you have any knock retard?I am thinking that injecting alky will help keep detonation down when using nitrous but first I should see if I even have a problem.There are a few items on the market that retard timing while the nitrous is on so you dont have to re-tune and run less timing all the time.

[PITBULL]

I am using a Racetech SDS ECU standalone computer that has a nitrous timing retard function. I am not sure I will need that though....Snow Performance claims that when you use WI with nitrous or a boost+nitrous application you don't need to retard timing whatsoever. Also, they mentioned that a 25% methanol to 75% water mixture is best in those types of setups so you don't overfuel. Also, as far as timing is concerned, you shouldn't need to retard anything if you're running a small (i.e. 50hp-75hp or less) shot.

I'll post results when I get a chance

[Rootzz06]

Pitbull--I'm going to run a setup like that too--I bought a timing control that can retard timing active when nos is on--but I am also waiting to see if I need it.I think we are going to have to run some alchohol for best detonation control.It would be nice not to have to retard timing.but also if the WI system fails I want a protection in place so nothing gets melted.Dyno tune has a nice new AFR lean shutdown for use with nitrous.Casper electronics sell a knock alert guage/alarm.I am thinking of a way to use the knock alert to shut down the nitrous or retard timing.I know the ECM in my car is sopposed to do that but......