Retard about to put nozzle before MAF on a dry kit!! Help me change his mind!!!!
09-22-2004, 01:14 AM
#1
Retard about to put nozzle before MAF on a dry kit!! Help me change his mind!!!! I messed up the title of the thread, I meant after, OH well, I got it right in here.
I have a buddy that is fixing to install a dry NOS kit on his 87 Iroc with the 350 TPI. I told him to put the nozzle BEFORE the MAF. Because we all know that the nitrous fogs the MAF and then the computer adds the correct amount of fuel for a safe mixture. My dumbass friend says the guy he bought it from said to put the nozzle after the MAF, right before the throttle body. I told him if he did this the computer will add no fuel, and his car will go lean and then bye bye. Someone else help me out in convincing him to put it BEFORE the MAF before he frys his engine.
I have a buddy that is fixing to install a dry NOS kit on his 87 Iroc with the 350 TPI. I told him to put the nozzle BEFORE the MAF. Because we all know that the nitrous fogs the MAF and then the computer adds the correct amount of fuel for a safe mixture. My dumbass friend says the guy he bought it from said to put the nozzle after the MAF, right before the throttle body. I told him if he did this the computer will add no fuel, and his car will go lean and then bye bye. Someone else help me out in convincing him to put it BEFORE the MAF before he frys his engine.
Last edited by BriancWS6; 09-22-2004 at 02:38 AM.
09-22-2004, 01:41 AM
#2
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you can put it after the maf as long as when the kit activates it bumps up fuel pressure to compensate for the nitrous... ie makes the injectors flow more...
if he doesnt have a booster pump that comes on when he activates at WOT he will pop his motor.
the LT1 Kits are like this... After the MAF, but when u activate the kit fuel PSI jumps to 90 i think... figure out which kit it is... Im not sure but I dont think Pre LS1 Computers compensate for the nitrous through the MAF that well and require the boosted fuel pressure...
find out what kit it is specifically and let us know
if he doesnt have a booster pump that comes on when he activates at WOT he will pop his motor.
the LT1 Kits are like this... After the MAF, but when u activate the kit fuel PSI jumps to 90 i think... figure out which kit it is... Im not sure but I dont think Pre LS1 Computers compensate for the nitrous through the MAF that well and require the boosted fuel pressure...
find out what kit it is specifically and let us know
09-22-2004, 02:00 AM
#3
well, it does have a booster pump that he gave him, but it didn't come with the kit, it was bought seperately. I don't know what kit it is, but it was used on a Mustang last. I just know that if there is nothing to compensate for the nitrous entering the engine it's all over. On the LS1's you put it before the MAF, I thought that's what you did on all cars with a MAF. I just don't want him to mess his car up.
09-22-2004, 07:21 AM
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Only LS1 models use the MAF to obtain the extra fuel. You need the booster pump and I think you tie into the FPR to spike the fuel pressure. You just need to make sure he has all the parts. Like said before, look how the NOS kit for the LT1 works. Thats how its gonna be.
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09-22-2004, 09:20 PM
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Heres how most NOS dry systems work. The kit utilzes 2 nos noids, the first one is there to stop nitrous from entering the nitrous mangagement unit ( similar to an FMU on a blower or turbo car. If it wasnt there the nitrous woluld automaticly bump up the fuel pressure causing a rich running motor, the second reason is it would eventualy blow the regulator up and the nitrous would also leak out of the line. When the first one opens it sends nitrous thru the NMU and a tiny amount of nitrous forces down on the regulator bumping up fuel pressure, this happens quikly and by the time it goes thru the second noid and thru the intake the fuel pressure is already up. On LS1 cars the extra noid isnt even needed. Its used realy to keep the price of the kit up and to make us think we arent getting cheated. Ill post a pic of the NMU tommorow at work. spraying behind the maf is common on cars with the NMU cause the meter doesnt need to richen up the tune.
09-23-2004, 06:49 PM
#11
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Originally Posted by riddler
Tell him it's a great Idea and then be sure to video tape the first time he hits it 
AH ha ha ha ha ha ha, AHH ha ha ha ha ha, oh my, fire's cool!, yeah yeah fire's cool!
09-23-2004, 07:30 PM
#12
Originally Posted by Steve@NitroDaves
Heres how most NOS dry systems work. The kit utilzes 2 nos noids, the first one is there to stop nitrous from entering the nitrous mangagement unit ( similar to an FMU on a blower or turbo car. If it wasnt there the nitrous woluld automaticly bump up the fuel pressure causing a rich running motor, the second reason is it would eventualy blow the regulator up and the nitrous would also leak out of the line. When the first one opens it sends nitrous thru the NMU and a tiny amount of nitrous forces down on the regulator bumping up fuel pressure, this happens quikly and by the time it goes thru the second noid and thru the intake the fuel pressure is already up. On LS1 cars the extra noid isnt even needed. Its used realy to keep the price of the kit up and to make us think we arent getting cheated. Ill post a pic of the NMU tommorow at work. spraying behind the maf is common on cars with the NMU cause the meter doesnt need to richen up the tune.
09-24-2004, 12:36 AM
#15
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Originally Posted by riddler
Tell him it's a great Idea and then be sure to video tape the first time he hits it
ps. save me a copy of the tape.
09-24-2004, 09:01 AM
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Originally Posted by BriancWS6
I didn't know that the pre LS1 cars didn't use the MAF to add the extra fuel. Better to post the thread and find out I'm wrong than take a chance on losing his engine. Thanks for the info, and the pic would be great.
This is the NMU (nitrous management unit) and its acompaning bypass T fiitng. The NMU works just like an FMU on a turbo or blower car. Under nitrous use it raises the fuel pressure just a hair to compensate for the extra airflow (nitrous) coming into the motor. The bypass T has a small jet in it to controll how much pressure is forced onto the regulator. If youve ever noticed when you pull the vacuum line off your FP regulator your fuel presure increases, Thats because at idle you have vacuum pulling the diaphram on the regulator which in turn drops fuel pressure. Under load or WOT your vacuum is gone and the diaphram closes back bumping up the fuel pressure. What the NMU and T fitting does is allow a small amount of nitrous to push harder on the diaphram increasing the fuel pressure even more. Sneaky isnt it!. This is a great way to add fuel without having to always have your FP up causing an all time rich condition. The first noid is what keeps this from happening. When its closed the NMU isnt in operation, but when it opens it works. I hope this makes sence to you guys. Here are a few pics.
09-24-2004, 12:38 PM
#17
Thanks alot for the pics and the explanation. As soon as he gets the car back we'll get the N20 installed. Thanks for everyones help and comments, I'll let you know the end results. What will be fun is still beating my buds car with a built 700R4, stall, 4.10s, slicks, and nitrous, gotta love the LS1!!!
09-24-2004, 04:06 PM
#18
I'll chime in here too...
This is from the 3.8 v6 setup I had (150 dry shot, 13.2 best et). I sprayed before the maf, and I had the dual solenoid setup with pressure to the fpr. I needed both to get the a/f where it needed to be. Fuel pressure would go up from 42 or so, to the 65-70 range. And the pcm would hold the injectors open longer too. I finally ran out of injector, and ran out of single nozzle flow capability at the 150 level.
Spraying directly in front of the maf was bad though. Maf readings were all over the place. Spraying as far away as possible in the lid was a lot better.
To clarify on the dual solenoid setup, if it's wired correctly, the second solenoid won't even open until the fuel pressure has risen.... That's with it tied to a correctly set hobbs switch on the fuel rail. So #1 opens, fuel pressure comes up, and then #2 lets it fly...
This is from the 3.8 v6 setup I had (150 dry shot, 13.2 best et). I sprayed before the maf, and I had the dual solenoid setup with pressure to the fpr. I needed both to get the a/f where it needed to be. Fuel pressure would go up from 42 or so, to the 65-70 range. And the pcm would hold the injectors open longer too. I finally ran out of injector, and ran out of single nozzle flow capability at the 150 level.
Spraying directly in front of the maf was bad though. Maf readings were all over the place. Spraying as far away as possible in the lid was a lot better.
To clarify on the dual solenoid setup, if it's wired correctly, the second solenoid won't even open until the fuel pressure has risen.... That's with it tied to a correctly set hobbs switch on the fuel rail. So #1 opens, fuel pressure comes up, and then #2 lets it fly...
