Some Nitrous Questions

D

DRock9

New Member
Aug 22, 2006
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#1
I have a dilema on my hands about what route to go with my car, I am not going to go with SC and N20 because my motor can't handle it and it doesn't make any sense to do SC before H/C/I because of the fact I have to take the SC off to install it.

I guess what I am going to do is to put a 125 wet shot on the car but I need to know what I will have to upgrade to so that it can handle it and my H/C/I in the future. It doesn't make much sense to me to buy 24lb injectors when I will need 48lb once I put my HCI on, it would just be money wasted.

I also can't seem to find a 125 wet shot from any good company, the only one I can find is Zex but i've been told to stay away from Zex. 125 is the max the stock block can handle correct? I want whatever the most I can get on my car, whether it be 150 or 125 as long as it is the best.

Right now I have BBK Headers, Mac H-pipe, K&N Filter, and Air silencer/MAF screen removal.

Questions:

1) Is it bad to go with injectors that are too big?
2) How much MPG will I lose by switching to 48's?
3) What size injectors would you reccomend for a 125wet shot + Trickflow Top End?
4) Also what size MAF should I get, 80mm?
5) What other fuel modifications do I need? Can I get away with just a newer 155lph fuel pump or is that too small?
6) What is better for injection, EFI Plate or Air Intake Tube?

Thanks for all your help! When you are done with the quiz please put it on my desk and I will have it graded by the end of class today.
 
#2
I think you're majorly confused about a few things. Your block is limited by power, not the size of the shot. I've sprayed 250hp on a stock shortblock several times. I have close friends that spray 300hp on their stock shortblock altough they do tend to push a lot of head gaskets. You'll have no problem spraying 150hp on a H/C/I stock shortblock combo.

1. The wet kit supplies it's own fuel. You only need an injector to supply the motor.
2. If it's tuned to the correct a/f. you shouldn't lose any mileage. The size of the injector will only cause a change in the pressure it must run at to supply a given amount of fuel. Your car is only going to use so much fuel. As long as it's not pig rich, you'll just run a lower pressure with a bigger injector. But a 48lb (which I've never seen before) injector is WAY too big for what you want anyway.
3. 24lb or 30lb at the most
4. PMAS 75mm or maybe an 80mm
5. Go straight for a 255lph. Why wouldn't you? They can be had for under $100 from www.jdsperformance.com.
6. The EFI plate is better. But that doesn't mean anything really. I'd go with the nozzle kit. It's just over half the cost of the plate kit and will work flawlessly for anything you're most likely going to use. I've put 250hp through a nozzle kit. Don't let some noob come in here and crying "pooling" when they have no experience on the subject and are just spewing crap they read from somewhere.

Nitrous Express FTW!
 
#4
At the risk of starting a war here I am going to throw my .02 in here. Everything fullAuto has said is correct. The only thing I am going to say is that I have SEEN several incidents where a nozzle wet shot was used and because of the long runners in the 5.0 intake the fuel has pooled and KABOOM blown the intake threw the hood 15 feet in the air. Like I said I have SEEN this happen and not just read about it. I am not saying this happens a lot as I am sure it doesn't but the safest bet is going to be the plate system but as said it is pretty pricey. I would go with a NX kit for sure as I have seen the NOS, ZEX, and NX kits and the NX kits are the best quality IMO. Basically you have to decide if the saving $400 on a nozzle kit is worth the chance that someday you get some pooling and there goes your intake through the hood. I am sure you could spray a nozzle kit for 15 years and never have a problem but the chance is greater with the nozzle over the plate system. Good Luck with your decision.
 
#5
Why have you been told to stay away from Zex? The only drawback to the Zex is that if you are tuning the car to the edge, the Zex management box will give you problems because of the way it is designed. They designed it to be much safer for the guy who just throws on nitrous but doesn't get a tune, bottle warmers and things like that to run the nitrous the way it should be. I run the Zex w/100 shot on my 347. Have been for well over a year. It hasn't given me a problem on my conservative tune for my daily driver.

75 or larger mass air meter
As far as the fuel pump go 255, 190 at the minumum.
24 lb or 30 fuel injectors with hci and the juice.
Yes it is bad to go with too big of an injector. If the car will even run it will run like crap. The f/p will be so low that the spray pattern will be horrible. It will be like a squirt/ drizzle than a mist. plus with a wet kit you need the f/p above a certain psi. I can't remember what my Zex book said.
Plate kits cost quite a bit more than a nozzle kit. But as to which one is better, well, they both do the same thing.......add power.
 
#7
No, it wont be the same as with a dry kit because on a dry kit the injectors are supplying the fuel for the nitrous so you will need more pressure to supply the fuel. On a wet kit it would be around 38 or so in order to spray i believe
 
#8
89streetbeast said:
my NOS brand dry kit called for 80psi fuel pressure, dunno if its the same for a wet kit or not:shrug:
Click to expand...

No it wouldn't be. A dry kit needs more fuel pressure because the dry kit relies on the fuel injectors for the extra fuel. A wet kit uses a separate fuel feed line to add the extra fuel needed during spray.

***EDIT***
I got beat to the punch :)
 
#9
I run a TFS plate kit, rebadged NX kit, on my 93 with a 100 shot. It took over 1 sec off my times. Personally I like the plate kits but that is just preference, I wanted one for Christmas last year so I asked big and got it :D. Your questions have been answered pretty well by the previous posters but I wanted to let you know about some other stuff you should consider adding with the nitrous kit.

I would recommend getting a window switch either digital or with rpm pills that you can swap out. It prevents engaging the nitrous at to low of an RPM and also protects against missed shifts and overrevving with nitrous. Saved my motor on a missed shift so it was well worth the $100 or so it cost.

Fuel pressure switch. Will drop out the nitrous if the fuel pressure drops below a certain PSI. Prevents you from spraying nitrous with low fuel pressure, not a good thing.

Like Fullauto said there will be some that will talk about puddling fuel in the upper with a nozzle kit. Does it happen? Yeah and if it backfires it can do damage but most of the time it is because the person running the kit didn't have the proper safety features or bypassed them and sprayed at to low of an RPM. The upper intake is great for flowing air but at lower RPMs it isn't so great for flowing fuel, even when it is suspend in an air fuel mixtures. This is where thing like the window switch come into play. I have mine set at 3k on 6k off. You will have sufficient air velocity to keep the fuel in suspended in the air. Puddling and backfires in the upper don't happen all the time but they can happen. Having the right equipment to prevent them is the important thing.
 
#10
RYC CUKR does make some good points about having the nitrous system setup correctly with a window switch. That will for sure lower your chance of having a problem with the wetkit and pooling. Whatever way you go you will be fine if you are just careful and don't get cheap with how you set it up. Set it up correctly the the first time so your not sorry later on down the road. Good Luck.
 
#11
Wow thank you all for all of the info! You have been awesome help, and I'm sure whoever searches for nitrous questions in the future will have all their answers found in here.

I was thinking about getting the four button panel from http://turbomustangs.com/store/store.php and I was wondering if that would qualify as a window switch or if I will need to get one separately. Also is a purge system and bottle warmer neccessary for me to use it? I plan on getting a warmer then purge(maybe) ASAP but I won't have it in time when I install the system...maybe a couple weeks later. Thanks again for all the help, you guys are amazing!
 
#13
Ok thanks, I didn't think that was one...also what keeps the nitrous from spraying when you are in 1st or 2nd? Do you hit the arm button in the middle of your run when you are going down the track?
 
#14
You really need a bottle warmer to keep bottle pressure where its optimal. A purge just purges air out of the line so you get the purest shot of nitrous. I spray through all 4 gears. I run with the wide open throttle switch. My window switch is 3000 rpm and 6200 rpm.
 
#16
bubba-dough said:
You really need a bottle warmer to keep bottle pressure where its optimal. A purge just purges air out of the line so you get the purest shot of nitrous. I spray through all 4 gears. I run with the wide open throttle switch. My window switch is 3000 rpm and 6200 rpm.
Click to expand...


and you still have a master switch that shuts off the whole system if you want...right?
 
#17
It's not that pooling doesn't happen. It does. But it's always, 100% of the time, without a shadow of a doubt, user error. I've seen it more than my fair share of times. I not only have been using nitrous for just short of 13 years but I also own a business that almost exclusively sells nitrous to other businesses. The long runner concept was an excuse people came up with to make themselves feel better. It's the same thing when people say 5.4" rod 347s burn oil. It's not the pin intersecting the ring, it's poor assembly.

If there were even on honest .01% chance of pooling without the user ****ing something up, I'd have blown up dozens of motors. I've sprayed 250hp through standard Shark nozzles (not even the SHOs) with no problems. And I've done it many times. Do I recommend this to customers? Hell no. I do a LOT of stuff I wouldn't recommend to customers. But I didn't start off doing most of the stuff I do now either.

As far as Zex is concerned, it's a beginner's kit. Their entire marketing ploy is ease of installation. They are definately easy to install. That's all they've got going for them. You'll mainly see modular owners and conservative pushrod guys use it. You aren't going to see many 10sec cars or guys getting aggressive running Zex. And pro racers? If they're not getting it free, they're not running it. About the only kit that makes them look good is Cold Fusion. Now there's some swap meet nitrous. Nothing screams, "I didn't research before I bought" like a Cold Fusion owner.
 
#18
Dont mean to Jack this thread but since your talking different brands of nitrous what do you think of DynoTune? I just bought a dry kit for my car, I havnt installed it yet but it looks like good quality stuff and its a nice complete kit for a good price. Any thoughts?
 
#20
cobra2798 said:
Dont mean to Jack this thread but since your talking different brands of nitrous what do you think of DynoTune? I just bought a dry kit for my car, I havnt installed it yet but it looks like good quality stuff and its a nice complete kit for a good price. Any thoughts?
Click to expand...

Their wet nozzle design is one of the best. I don't sell it and there may be a few cons compared to some other brands (but there are with everyone), but nevertheless it's one of the top brands on the market. I have no experience with their dry kits though.
 
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