I can get a wet kit from my buddy, but he just has the nozzle's that you tap into your intake tube after the air filter. Has anyone used Nitrous on a TPI motor without using the plate? How much of a difference? what kind of concerns would there be?

Ryan

 

I used nitrous on my 1996 S-10 4.3 I had a wet nitrous works system from an LS1 on it and jetted at a 75 shot. I dropped from a 15.7@87that night to a 14.0@95. I loved the nitrous but filling the bottle got $$$$$$$! $35 to fill a 10# bottle here.

 

also mine was a fogger nozzle like the one youre talking about. You can use it on your car. Just remember to retard the timing on your car according to the shot youre going to run. A wet system is the safest system. Way better than a dry system.

 

how do you adjust your timing on a car that has a computer controlled timing? I thought you could only change base/idle timing, and that changing that doesn't really effect anything

Ryan

 

And why is that? A dry shot enriches the mixture thru the injectors. actually it is probably safer as you don't have another solenoid to worry about.
You can retard your timing a couple of different ways. Depends if you want to spend money or not. You can back up your base everything will follow.

 

There were 2 main reasons that NOS got away from the fogger nozzle setup for tpi's and LT-1's. They really only flow a max of 50hp of nitrous per nozzle, and fuel distribution sucked, oh yeah plumbing sucked to. You can buy plates used for 100.00 or so. I would NEVER plumb a wet system that far away. Buy a plate and it will help the fuel atomization. Nitrous is not the place to cut corners or experiment if you have no experience.

 

The injectors will only compensate for so much. The ECM has a programmed compensation limit before it throws a code. The typical rule is if you're going 100+ hp shots, go wet.

 

Man, you guys are giving me a headache.

First, dry kits add fuel by using the n2o pressure to boost your fuel pressure. The ECM has no idea what the fuel pressure is and at WOT the O2 sensor doesn’t effect your mixture. If you raise pressure, you get more fuel, as simple as that. The ECM won’t know and won’t do anything about it. It’s not going to throw a code.

Second, yes, dry kits add fuel at the injectors, but that doesn’t necessarily make them better. There is almost no way to exactly, repeatable dial in how much fuel will be added, and if you change your fuel system, especially injectors you’re starting from scratch with figuring out roughly where you need to be with the fuel jet. A bigger problem is that generally, GM injectors aren’t too happy with high fuel pressures and chances are pretty good that when that solenoid opens and the FP spikes the injectors lock and you get _no_ fuel. N2O + lean condition = boom

Wet systems meter the actual fuel delivered by a jet, so you can change and dial it in relatively consistently. Fuel pressure changes will change the amount of fuel delivered, but that can be calculated just like you calculate what the fuel pressure does to the injector flow.

Personally, I feel that dry setups are great for <100hp, 125 at the outside, above that your much better off going wet.

Third, as far as where/how you inject… there are plenty of fogger type nozzles that are great for well over 50hp, some getting into the 250hp range. The problem with the plate/bar setup is that they are usually setup with the spray bars an inch or so apart on the TPI style setups, with the holes drilled so that the 2 streams intersect an inch or so into the plenum. Not only does this tend to give you a iffy N2O/fuel mixture, but take a look around your plenum, what do you think happens to the first couple cylinders?

Fuel/N2O fogger nozzles are designed so that the fuel comes up the middle and the N2O comes from behind it/around it. The N2O at roughly 1000psi shears the fuel stream atomizing it on the spot, giving a more consistent mixture. Assuming that you inject it at a reasonable time (IE, only at WOT and at a sufficiently high rpm that the airflow through the intake is at full boogie, say over 3000), your distribution will be roughly similar to that of the airflow, something that you’ll never see with an EFI plate system unless the whole intake was designed around the N2O plate.

Secondly, the option of mounting the nozzle where you want becomes a tuning option. Typically, you want to mount it within 6”, or maybe a foot at the outside of the TB, but the closer you get it to the TB the harder it hits, the farther you go from the TB the softer it hits. Consider this when you try to launch something like an L98, with just enough (way too much ) torque, a 3.06:1 first gear, typically 3.73 rear gears and something like a vigilante converter with a 2.5:1 torque multiplication ratio… do you want that spray coming in soft or hard?

 

Thanks 83 Crossfire TA...VERY good information. It actually makes things easier for me, cause if I don't have to buy a plate I'll have a complete fogger kit in a straight up trade. I was hoping I wouldn't have to fork out for a plate since I prolly won't use the nitrous for very long. I'm kind of a believer in NA power or if any power adders... a turbo or supercharger. Nitrous will give me the edge I need now to blow away my buddy's 95 V6 Probe with a custom turbo setup. Don't laugh, it's FAST!!! Stand alone fuel and spark, GM turbo off a 6.5L diesel, 3 inch downpipe and exhaust, custom fuel rail, millenia injectors (bigger), and running 8-9 psi. Yeah, it's high maintinence and is on the edge of blowing, but hell it gets a car and a half from 60-90. That's when I catch up...surprisingly...I've got long tube headers, 3 inch exhaust, edlebrock base manifold, and a open K&N. With the headers I'm getting a lot of pull up top, especially above 100. Bone stock I was able to hit 140, but between 110-140 there wasn't much pull, now there is a lot of pull up there.

The other thing I'm concerned with is timing. Is retarding base timing going to effect anything? And fuel....is what kinda pressure should I run? I need to get a AFPR too, lol.

Ryan

 

Yeah, I'm stupid. I shouldn't post after 10 PM.

 

I can make just about anything go faster, but I don’t think I can help that

If you were set on it I’m sure I’ve got an NOS plate here that I could sell you, but I don’t really see the point.

I hope that you’re not running to those speeds on the street (I’ll admit that I’ve done it, but it was also in a more controlled environment than your typical streetrace). If I remember right, those probes should be around 145hp stock, 10psi would still put him at under 240hp which should still have him within range of an L98 with the mods you’ve listed, and not that far away from an LB9… maybe some time spent tuning/tweaking is in order?

After a lot of tinkering, I found that my formula ran EXACTLY THE SAME times at the track with the timing set anywhere between 4 and 14* (past that it pinged and slowed down, I didn’t try lower) so I’ve had it at 4* for a while now. Retarding the timing isn’t even recommended by all the N2O kit manufacturers (ex, NX recommends against it). The fact is that timing has very little effect when you’re spraying, the mixture is harder to ignite and ignites later but once it does the extra O2 causes it to burn faster so the net effect is that you could probably advance the timing slightly or retard it A LOT and still see very similar power numbers.

The reason that timing is retarded when spraying is that most cars are very close to spark knock anyway, and if you get it with an extra 150hp or so going through the engine it will do more damage. Typically, if you’re talking a 100-175hp shot, you should be able to leave the timing alone, run some plugs a heat range or 2 colder and you’ll be fine. (based on my experimenting with it I’d probably set the base timing at 4* and run some ac 41 or 42 plugs in a 350 and some 43’s in a 305)

 

I run a single nozzle setup from nx. I have it jetted now to 150hp but it will support up to 250hp. I am going to jet it to 200 soon and I will let you know how it works. BTW I got the nozzle mounted about 10" from the TB and it does not hit that hard at all. Had a plate system before and it worked good also but hit a lot harder. Had to wait almost to second gear before hitting it with et streets and a lot of suspension mods!