I heard goods and bads about the NOS TPI kits, and have heard good about NX, but haven't heard much about them period. I'm just looking for inputs about both. Also, I read that NX doesn't use the plate like NOS, and in that case, how does it work? I know the NOS kits go for about $450 new, what are the prices on NX and where can you get them? Thanks.

------------------
'89 Camaro RS 6cyl. auto, don't know how much longer I'll have it.
'90 Iroc TPI 305, 5 spd B&M Ripper shifter, hopefully I can rob a bank or something and get more
www.geocities.com/irocnroll90

 

NX is an overall better kit...but it is also more expensive. The main diff. is the 'noids. NOS are puny looking compared to NX. NX acessories are much better tho. NX works w/a fogger nozzel type. I'd stay away from a plate system coz they have flow distribution problems. Derrick

 

Are you telling my90iroc to go to a fogger? Or are you saying that one nozzel in the intake track atomizes and distributes better than a plate?

If one nozzel in the intake was superior than carb guys would follow suit.

I like the plate but wouldn't buy an NOS system again.

------------------
1991 Firebird
350 L98 (was a 305 TBI)
T-5 transmission
Edelbrock TES and cat back
Accel manifold
NOS
subframes
jegster torque arm
MSD Digital 6
AFPR
Lakewood lcas
Hurst linelock
SLP cam (206 212 .480 .486)
relocated battery
cold air
Hypertech chip
centerforce df clutch
poly bushings and mounts
AFR 190s
Harland sharp 1.5 rockers
a/f gauge
autopower rollbar

12.44 @ 114.63 juiced uncorrected

13.549 @ 102 non juiced uncorrected

 

putting a plate under a carb and putting a plate behind a a throttle body are two different things.

What seems to happen with the NOS kit is that the first two cylinders dont get distributed well...that is why the NX one is better because it puts it in the intake tract

 

I really think that the principal behind placing a plate under a carb and behind a TB are very similar. As common knowledge, the less bends that a mixture, whether it be air/fuel or n2o/ fuel, undergo the less likely that mixture is to, well, unmix. So, placing a fogger nozzel in the intake tract(even a straight shot before the TB) will cause that mixture to be separated into componets more so than a plate.

 

From what I recall, there is also an issue of initial mixing. that is to say that you get a better mix out of a fogger nozzle than you would a plate so you can afford for some of it to drop out & still be better than a plate.

The owner of the Vette shop that I goto, had someone make him some plates that he put fogger nozzles into (behind the TB) & he put the same nozzle ahead of the TB, in the intake track. He got about the same performance from both of them. He was selling the plates (He sells NX btw), but has stopped. it is simpler just to put the nozzle into the intake right ahead of the TB & call it a day. there is not moving of the TB, no adapter for the cable, no longer bolts etc. & you can get those nozzles to flow a ton of fuel, & more importantly, imo, is that it flows well & mixes well.

& all that was said about the NX solenoids is true as well, they are just better quality & higher flow, BUT more $$$.

If anyone wants to see one of those plates that he made, I can get some pictures.

BW

------------------
Bobalos
aka Bob W.
www.r71camaro.homestead.com
r71chevy@earthlink.net
<><

 

As stated the NX solenoids are larger, allowing more HP. The NX kits are rated at rear wheel HP. That means an NX 100 HP jetted kit makes 100 HP at the rear wheels. I don't know if it is still true but NOS used to rate their HP at the crankshaft. That is why they used smaller solenoids in the kits. Both kits can make great power, You just need to use larger jets in the NOS kit to get the same rear wheel output. NX kits have a high flow bottle valve. With NOS that was an extra cost option. I don't know if it still is.
The reason the plate kits have distribution problems in the front two passenger side cylinders is not so much a dropout issue, that can happen either way. The issue is that the spray bar in the plate is so close to the entrance to the runners for those two cylinders that the n2o and fuel don't have enough room/time to get mixed in the first place. The biggest part of the nitrous plume and fuel spray right past those two cylinders, mixing in the air inside the plenum. A fogger type nozzle mixes the fuel and nitrous closer to the nozzle. By mounting the nozzle in front of the throttle body instead of behind it the nitrous and fuel have more time to mix thoroughly before reaching those first two cylinders. Of course after that, dropout becomes an issue with either kit.
NX has two kits for TPI engines.
•One is a single stage kit with jets for 50, 75, 100, 150 HP.
•Another is a two stage kit that includes the above kit plus a second additional stage of 50, 75, 100, 150 HP.
You can also buy the single stage kit now and buy a second stage kit as an add-on later.
NX makes a better bottle heater control. It is based on bottle pressure. That is the whole idea of having a heater in the first place, specific pressure not a specific temperature.
Just my own opinions, but I think the NX kit is well designed and worth the few extra bucks.
I got mine from a buddy that is an NX dealer.
He gets $472.00 for a single stage TPI kit. I have seen them going from mail order houses for anywhere from $470-$490 on average.

------------------

Tracy /AKA IROCKZ4me
'86 IROC-Z Camaro
"Cogito ergo zoom"

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

EFI Performance Club on Yahoo

 

FYI, in a plate system the fuel and nitrous mix almost in the spray bar. The holes are angled so that the fuel is sprayed directly into the n20. So stating that the two don't have enough time to mix is completely false. In my opinion, the closer the juice/fuel mixture is to the cylinders the better. Hence the reason that a fogger is superior. By your logic why not just inject it right behind the air filter? That will give it plenty of time to mix, right? Plus with a plate system, there are numerous nozzels to mix instead of just one in the intake tract. Smaller orifice=better atomization.

 

FYI, he said thoroughly mix, yes they will have already mixed some with a spray bar, but with the fuel and nitrous that close to the runner the two will not have mixed all the way by the time it reaches the first runner. besides, he was just stating an opinion and so were you, so dont go around saying he was completely false.

[This message has been edited by TexasLT1 (edited June 13, 2001).]

 

Guys, I'm not a NOx guy... here is a different perspective:

The TPI manifold was designed as a dry flow intake. Fuel distribution was not a consideration. It seems that by injecting fuel prior to the runners you are asking the system to do something it cannot do due to its design. What happens if a cylinder gets 150 hp shot of nitrous but only 75 hp of additional fuel because the fuel is heavy and couldnt turn the corner? This has the potential to be a very dangerous situation with a dry flow manifold.

Again, I know very little about nitrous but isn't a setup where the jets are in the runners a much better solution with a dry flow intake?

 

Well said TexasLT1. That's why this is called the "thirdgen.org message boards" and not the "my opinion is the only one that counts or is right board"
By the way the part about the spray bar in the TPI plate systems being to close to the first to ports is not ony my personal opinion but apparently that of the NX engineers too. At least that is why the NX guys I talked to gave me for them using the shark nozzle setup they use on their TPI kits That and also that their shark nozzle had better atomzation of the fuel and a more thorough mix of the fuel and nitrous.

No putting the nozzle near the air cleaner wouldn't be better...DUH. Why not just put it in front of the grill opening by the foglight housings. Yeah thats the ticket. Unless I can find some of those osmosis spraybars.

Now really, the closer to the throttle body the fogger is, the better off you would be to reduce drop out. But by being 3 or 4 inches or so away from the entry of the first two cylinders you should improve mixture quallity to those cylinders. One system sprays behind the throttle body, the other (if properly installed) sprays just in front of it, (not at the air filter). I don't think the length of the thickness of the throttle body would cause too much drop out, but may improve the amount of nitrous and fuel getting in those first two cylinders

Yes Dan W, a dry ntrous system would have the most equal distribution of all. The only reason I can think of for every manufacture not using that setup would be the difficulty in getting the correct amount of fuel enrichment though the fuel injectors. If everyone had a stock TPI with stock injectors then that wouldn't be too hard, but with custom mods and non stock size injectors a way to change (and get it right) the fuel enrichment would be required. Most (if not all) of the nitrous manufacturers try to make installing and using their kits as fool proof as possible, and sell to as wide a range of people as possible, so making a kit that would be easy to get the nitrous/fuel mix wrong is out. You also have to make sure that your injectors are not already maxed out. you need enough "head room" in your injecor sizing to cover not only your engines natural output but also that of the nitrous system.
But counting out "stricktly bolt on" users, If you knew what you were doing you certainly could get great results this way. The DFI computers and PMS piggy back computers have fuel enrichment tables for dry nitrous systems. But if you are just getting one of those for the dry nitrous use that would be a little expensive, and if you made a calibration error on the lean side it could get verry expensive.


So the next best thing would be individual port foggers. Of course that is expensive and takes up a good bit more room than a single(or double) fogger nozzle or plate system. But as near equall as posssible amouts of nitrous & fuel are deliverd to each port.

------------------

Tracy /AKA IROCKZ4me
'86 IROC-Z Camaro
"Cogito ergo zoom"

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

EFI Performance Club on Yahoo


[This message has been edited by IROCKZ4me (edited June 14, 2001).]

 

PS:
FYI...
If you haven't noticed, I love a good (or bad) debate!

 

Alright, IrocZ4me, please consult your freshman biology book before making anymore posts. I find your reference to the "osmotic spraybar" to be somewhat sad.


By your logic, by placing the nitrous 3 inches in front of the throttle body, you achieve a more thorough mixture in the plenum. You may be right. But this might not solve the distribution problem. As the fuel/nitrous mixture is accelerated by the air, it approaches the same velocity of the air travelling through the throttle body. Assuming that the fuel and nitrous are thoroughly mixed at this point gives the combination a much greater momentum travelling towards the rear of the plenum, thus causing an increasing nitrous/fuel gradient as you travel towards the rear of the plenum, and a subsequent distribution problem.


By using the plate system, you do lose the three inches of mixing distance, but this situation is remedied by the violent colision of nitrous and fuel brought about by the "osmotic spraybar" I believe you called it. The less velocity the nitrous/fuel mixture has as it fills the plenum, the more likely it is to stay in suspension (less momentum) and evenly distribute itself throughout the plenum. Moreover, I would readily give up three inches of mixing at a velocity of 246 ft/s (168 MPH)(it covers this distance in a time of .001 seconds) to decrease the total velocity (momentum) of the mixture. The velocity of the air coming through the throttle body >> velocity of the air through the plenum. This is because the air expands to fill the volume of the plenum.


Now let's talk about the instantaneous pressure gradient that aids in distribution. Once again, because of the momentum of the incoming air, the rear of the plenum will have more air per unit volume than the front of the plenum (pressure in back > pressure in front). Now we have 2 situations
#1. Your way
#2. My way


Your way, the momentum of the nitrous/fuel mixture collides with the rear of the plenum, sits there, and waits for it's own intermolecular forces to distribute itself against the pressure gradient. My way, much less velocity and the mixing and distribution occur along the pressure gradient. Because there is less pressure in the front of the plenum, the mixture first fills this volume, distributes itself evenly, and is carried to the rear of the plenum by the velocity of incoming air.


I realize that these points are two extremes, and that the correct answer lies as we approach a comprimise between these two extremes, but I'm going to bet the answer lies more on my side of the spectrum.

Also, do not believe everything that an engineer tells you. You should realize that it is much less expensive for Nx to use one nozzle than it would be for them to manufacture the plate system used by NOS. It is probably just a cost issue that they try to back up with information people will readily accept.

 

NOS supports my argument. But take it with a grain of salt because they sell plate systems.

From: nos@support.holley.com
Date: Thu, 14 Jun 2001 08:56:56 -0700
Subject: Re: Plate or fogger nozzel? [T20010614003S]
To: jmay@eng.utoledo.edu
X-Mailer: Microsoft Outlook Express 5.00.2615.200


The plate will give you better atomization and distribution. They are
probably not significant gains but would be better. By using the plate you
avoid the risk of turbulent flow through the throttlebody.


Thanks, NOS tech dept.

 

It was a joke Get over it.
I don't think I could consult my freshman bio book because I doubt I could find it. It's so old I would have to brush up on my latin to read it any way. (that's a joke too, implying it was written when latin was still a living language.) I think my senior physics book (written in Egyption hieroglyphics, it's so old the paper mites that lived there have died, fossilized and have been carbon dated to determine my graduation date) or my daily occupational use of reverse osmosis filtration devices fueled my joke. Either way, it was a joke.
For the nitrous to virtually mix inside the spray bar instead of mixing outside of it when the nitrous plumes intersect the fuel sprays and mixing there, the nitrous or fuel would have to pass through an aluminum barrier (not exactly a good semiperemeable membrane but I took a little artistic license to make a joke).

I'm sure you are right about taking things engineers say about their own designs & products with a grain of salt. I believe the same way. They all obviously have a biased opinion and believe they have chosen the best option available. Of course what criteria they based their best choice from may not always be the same criteria or be weighted the same as each of the rest of us might choose. Production cost is always considered But then from what I have seen NX hasn't cut corners in too many places based on cost. They could easily use smaller less expensive solenoids in their kits and use smaller "standard" sized bottle valves that others use. They could use cheaper thermostatic based bottle heater controls instead of higher priced pressure based transducer. They could offer a cheaper flow restricting solenoid type remote bottle valve. But they just don't because it isn't good enough. Given all that I doubt that they would choose a nozzle over a plate because of any cost difference. I'm sure it would be a small difference if there is any anyway. Since they also produce many spraybar systems, (some very exotic) They must also feel there is a good reason to use them on certain apps. I would be willing to believe that ease of installation may have been an issue in their choice of a nozzle for most mutiport EFI systems they produce. After all the real bottom line is based on how merchandisable a product is. They want to sell as many kits as possible. So if a nozzle system works well and it is easier to install then more consumers are likely to choose it. I also keep in mind that NX is all about building a better mouse trap. They don't want to make a good system, they want to make the best system and their unique products point to that. Their products cost more to produce and therefore sell for more but in my opinion they are well worth it. (except maybe for that pricey bottle blanket, but then there heater is so good you don't really need a blanket unless you run in the arctic circle.)


The point about inertia causing the fuel in the nozzle system to potentialy rush past the port inlets and "splat" on the rear of the plenum is certainly valid. The question is "is distribution unbalanced more from that or from the nitrous/fuel mix coming from a spray bar being swept away from the inlet of those first two cylinders by the high velocity airflow coming through the throttle body?" Another question that brings up is "would a larger throttle body with higher bulk flow but less velocity be a better choice as far as nitrous use and dispersion is concerned?" Hmmm...


Anyway both systems obviously work and work well. At least they do at the power levels they each are designed to.

I personaly favor & choose the NX system. It works very well for me and I have seen other cars pick up when switching from other brands to an NX kit. The buddy that I mentioned that is an NX dealer sells a lot of kits at the dragstrip that way. Real world testing. When he sees someone running another brand of kit he offers them a chance to test an NX kit in their own car. He tells them that they can install an NX kit jetted at the same level that they are already running with their own kit and their car will pick up (usually atleast 2 or 3 tenths in the eighth, more in the quarter). Not many people pass up a chance to do a free test just to see. He has sold a lot of systems that way. I don't know of any time that a car has not picked up.


[This message has been edited by IROCKZ4me (edited June 14, 2001).]

 

I have a great idea. how about we cut the top off of one of those TPI plenums, tap some holes into it & put a Lexan top onto it. now we can strap the car to a dyno & do a nozzle vs plate test. this way we can broadast it on the Web so that we can all watch for ourselves & see what happens.

who's game?

BW

------------------
Bobalos
aka Bob W.
www.r71camaro.homestead.com
r71chevy@earthlink.net
<><

 

How does the NX kit work? Does it have a WOT switch and an arming switch like the NOS kit, or is it different? Thanks again.

------------------
'89 Camaro RS 6cyl. auto, don't know how much longer I'll have it.
'90 Iroc TPI 305, 5 spd B&M Ripper shifter, hopefully I can rob a bank or something and get more
www.geocities.com/irocnroll90

 

Yeah Bobalos, that is a test I would like to see. Filmed in High resolution for good slow motion viewing. Also using thermocouples on all header tubes.

<hr>

Yes the NX kit comes with a toggle type arming switch that lights when armed, and it comes with a micro lever switch for WOT activation. Of course you can use any other swiching methods you may want to as well.

 

hey i got a better idea for the distribution test. how about we get everyone with a 305 peanut cam motor and have them spray a 250 a 300 and a 400 untill they blow their engines. with both kinds of systems. then we can inspect the remains and figure out wich is better. The 305 peanut cam motor will not be a big loss. the people that own them need 350's any way.

------------------
90 IROC l98
last season best corected 13.62 @102
mods
full exhaust, AFPR, pulley, jet stage 1 chip, billet servo, 52mm throttle body, slp runners and some 1.6 RR's and a few other little things.
243 RWHP and 342 RWTQ with hot engine and 90 octain fuel