NOS Kit...bad idea?
10-20-03, 11:37 AM
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NOS Kit...bad idea?
I know the subject has probably been beaten to death, but I have a friend that wants to sell me a nitrous kit for $200, all I'd really have to do is have it instaleld and maybe add a bottle warmer and auto-valve. Does any one out there have an experiences they can share about nitrous? Would it be worth the $350 (installed) it will cost me? Would anyone recommend a certain exhaust or intake? I am not a racer, don't want to spend the $10k for a decent turbo kit, and probably won't have a problem with refilling the tank every week. I'm just planning on using it for occasional traffic light races. This is for a 2nd gen GS4.
10-20-03, 12:12 PM
#2
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Are you going to dyno tune it as well or just stick the kit on? Are you going to use a window switch? The cost of the kit is good but its everthing else involved.....
10-20-03, 12:16 PM
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I'm not sure what a window switch is, if you're talking about a "full throtte" switch, yes, it would be full throttle only. I suppose a dyno tune may be in order. I am just concerned that 995 of my driving will not include NOS, so why would I want to make timing adjustments and tune it for NOS runs? Unless it's absolutely necessary or highly recommended.
10-21-03, 08:28 AM
#4
Lexus Test Driver
Let me give you a little bit of advice about Nitrous (it's not NOS people, it's n-i-t-r-o-u-s. NOS is a BRAND 
):
I've used nitrous on my other car for 3 yrs. I started with the very simple single fogger dry setup, all the way up to the direct port setup on there today. The key to nitrous usage is TUNING. Tuning is the proverbial missing link and the source of a lot of fallacies about nitrous. Nitrous by itself does absolutely nothing. It is an oxidizer. An oxidizer works as a catalyst in internal combustion engines to make it possible to burn more fuel. The burning of MORE fuel is where the HP comes from, not the nitrous. So it stands to generally reason....why not put more nitrous in and hence be able to burn more fuel to get more HP? Perfectly fine, except this is where AFR come into effect.
If you pump in more nitrous than fuel, that makes a condition called LEAN. Lean mixtures is what causes engines to BLOW. If the opposite happens (too much fuel, not enough nitrous), then you have a RICH mixture. The rich mixture is "safe" as far as the engine damage is concerned, but it also robs HP. The trick is to run the car at the right "mix" to get the most HP without blowing parts up.
Another big enemy of nitrous is detonation, i.e. pinging or knock. This occurs when octane levels are too low for the load on the engine, internal cyl pressures are too high, incorrect ignition timing, or even too high of engine temps. The knocking comes from the gas/air mixture inside the cyl gets lit before it's normal time. Therefore, it's obvious why you would not want the piston on it's way up when you pump nitrous (which increases the cyl pressures dramatically to make HP) then pushing the cyl back down when it's not supposed to. This where a lot of our parents horror stories of "thrown rods" thru the block come from. They forgot to retard the timing of the "hot rod" before sending nitrous in.
With all that said, nitrous is a safe and cost effective way to obtain instant HP boost. The key is remembering the nutshell info I just went over. Timing you can do nothing about in our cars. It is controlled by the ecu. You can put in "colder" plugs as a "backyard" way to ward off detonation. You also have to run premium whenever you run nitrous. You also have to control fuel pressure to ensure either to put more or take some away when tuning. If additional fuel is needed, sometimes is good to add in a more powerful fuel pump. This will ensure you don't starve the engine of fuel at the critical times when running nitrous.
As for additional equipment: A bottle heater (not just blanket) is crucial to any setup. Nitrous is a very very cold liquid with a very low boiling point. When the nitrous is exposed to any heat, it turns into the white gas everyone has always seen. While in the bottle, the amount of nitrous in the bottle determines the amount of pressure the bottle has. The more pressure, the more nitrous comes out when activated, etc. When the bottles starts to lose any amount, the pressure significantly drops reducing the amount of nitrous flowing. This interferes with tuning because you have "tuned" your car for X amount of nitrous and Y amount of fuel. If any of the two is reduced, it automatically makes the other more. In other words, if your pump can't keep up and suddenly loses fuel pressure....then you will have more nitrous than fuel, hence LEAN, hence BOOM. The same way....if you have plenty of fuel, but suddenly the nitrous pressure drops.....super RICH happens, and you lose a ton of HP. This is why if you heat the bottle at constant temps (people use to cheat by heating the bottle at the track with a blow torch
) it will remain at a constant pressure, therefore if you can control the fuel pressure when the system is engaged then you will have a properly tuned system for your car. See how it all fits together.
Finally: A window switch is a relay box that temporarily shuts down the flow of nitrous during shifts. This is used primarily in 5spd cars because it is not good to "spray" between shifts or "spray" if you accidentally miss shift and hit the rev limiter. In an auto car, it is not necessary to have a window switch because the ecu will control the shift points (if you let it). I have never used one in any of my auto cars.
BTW, the amount of HP derived from any NOS system is based primarily on "pills" or "jets". These jets have a set orafice opening. Based on the size of the orafice you can determine different combos of fuel jets and nitrous jets to derive at the desired HP level. Always remembering that the more you go up, the more fuel you need, less timing, etc.
There are several kits that take a lot of this "tuning" guesswork away. ZEX makes a very good one that requires no additional fuel pumps or anything. It is a WET kit though. These kits are "safer" to use for the novice. I felt I should briefly touch on the theory behind nitrous, so that regardless which kit you choose...you know why things happen the way they do.
To explain a WET kit: Well, maybe next time.....
):I've used nitrous on my other car for 3 yrs. I started with the very simple single fogger dry setup, all the way up to the direct port setup on there today. The key to nitrous usage is TUNING. Tuning is the proverbial missing link and the source of a lot of fallacies about nitrous. Nitrous by itself does absolutely nothing. It is an oxidizer. An oxidizer works as a catalyst in internal combustion engines to make it possible to burn more fuel. The burning of MORE fuel is where the HP comes from, not the nitrous. So it stands to generally reason....why not put more nitrous in and hence be able to burn more fuel to get more HP? Perfectly fine, except this is where AFR come into effect.
If you pump in more nitrous than fuel, that makes a condition called LEAN. Lean mixtures is what causes engines to BLOW. If the opposite happens (too much fuel, not enough nitrous), then you have a RICH mixture. The rich mixture is "safe" as far as the engine damage is concerned, but it also robs HP. The trick is to run the car at the right "mix" to get the most HP without blowing parts up.
Another big enemy of nitrous is detonation, i.e. pinging or knock. This occurs when octane levels are too low for the load on the engine, internal cyl pressures are too high, incorrect ignition timing, or even too high of engine temps. The knocking comes from the gas/air mixture inside the cyl gets lit before it's normal time. Therefore, it's obvious why you would not want the piston on it's way up when you pump nitrous (which increases the cyl pressures dramatically to make HP) then pushing the cyl back down when it's not supposed to. This where a lot of our parents horror stories of "thrown rods" thru the block come from. They forgot to retard the timing of the "hot rod" before sending nitrous in.
With all that said, nitrous is a safe and cost effective way to obtain instant HP boost. The key is remembering the nutshell info I just went over. Timing you can do nothing about in our cars. It is controlled by the ecu. You can put in "colder" plugs as a "backyard" way to ward off detonation. You also have to run premium whenever you run nitrous. You also have to control fuel pressure to ensure either to put more or take some away when tuning. If additional fuel is needed, sometimes is good to add in a more powerful fuel pump. This will ensure you don't starve the engine of fuel at the critical times when running nitrous.
As for additional equipment: A bottle heater (not just blanket) is crucial to any setup. Nitrous is a very very cold liquid with a very low boiling point. When the nitrous is exposed to any heat, it turns into the white gas everyone has always seen. While in the bottle, the amount of nitrous in the bottle determines the amount of pressure the bottle has. The more pressure, the more nitrous comes out when activated, etc. When the bottles starts to lose any amount, the pressure significantly drops reducing the amount of nitrous flowing. This interferes with tuning because you have "tuned" your car for X amount of nitrous and Y amount of fuel. If any of the two is reduced, it automatically makes the other more. In other words, if your pump can't keep up and suddenly loses fuel pressure....then you will have more nitrous than fuel, hence LEAN, hence BOOM. The same way....if you have plenty of fuel, but suddenly the nitrous pressure drops.....super RICH happens, and you lose a ton of HP. This is why if you heat the bottle at constant temps (people use to cheat by heating the bottle at the track with a blow torch
) it will remain at a constant pressure, therefore if you can control the fuel pressure when the system is engaged then you will have a properly tuned system for your car. See how it all fits together.Finally: A window switch is a relay box that temporarily shuts down the flow of nitrous during shifts. This is used primarily in 5spd cars because it is not good to "spray" between shifts or "spray" if you accidentally miss shift and hit the rev limiter. In an auto car, it is not necessary to have a window switch because the ecu will control the shift points (if you let it). I have never used one in any of my auto cars.
BTW, the amount of HP derived from any NOS system is based primarily on "pills" or "jets". These jets have a set orafice opening. Based on the size of the orafice you can determine different combos of fuel jets and nitrous jets to derive at the desired HP level. Always remembering that the more you go up, the more fuel you need, less timing, etc.
There are several kits that take a lot of this "tuning" guesswork away. ZEX makes a very good one that requires no additional fuel pumps or anything. It is a WET kit though. These kits are "safer" to use for the novice. I felt I should briefly touch on the theory behind nitrous, so that regardless which kit you choose...you know why things happen the way they do.
To explain a WET kit: Well, maybe next time.....
Last edited by jmecbr900; 10-21-03 at 08:34 AM.
10-21-03, 08:54 AM
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Hey man, the longer the wind, the more info...that's what I'm here to get. 
Very informative post, thanks. I pretty much know the dangers of running too lean and blowing the motor, I also understand that the 1UZ-Fe has a farily strong top end.
I did however have concerns about the automatic tranny and nitrous flowing too much during shifts, should this not be a concern?
You said timing can't be manually adjusted, but the dealership told me they charge for a timing adjustment after they put new plugs in...is this BS, or do they adjust the timing via ecu? I figured it was BS, changed the plugs myself and haven't had any noticeable timing problems.
I have denzo iridium plugs, will they suffice for use with nitrous? And I guess I should increase the gap size? I am planning on using the 75 shot, dry.
Very informative post, thanks. I pretty much know the dangers of running too lean and blowing the motor, I also understand that the 1UZ-Fe has a farily strong top end.
I did however have concerns about the automatic tranny and nitrous flowing too much during shifts, should this not be a concern?
You said timing can't be manually adjusted, but the dealership told me they charge for a timing adjustment after they put new plugs in...is this BS, or do they adjust the timing via ecu? I figured it was BS, changed the plugs myself and haven't had any noticeable timing problems.
I have denzo iridium plugs, will they suffice for use with nitrous? And I guess I should increase the gap size? I am planning on using the 75 shot, dry.
10-21-03, 09:43 AM
#7
Lexus Test Driver
Unless there's a way I'm not aware of or it's different on older GS's.....the timing is controlled strictly by the ecu. There is no handheld that can change the ecu. In order for the ecu to change the programmed timing map is to be a custom ecu.
As for spraying during shifts, the window switch is very inexpensive. The added safety is worth the cost. I personally have never used because I had custom valve bodies on the auto's and therefore the shifts were almost instantaneous. So what little amount I sprayed while shifting was minimal. Besides my auto tranny is built so it could stand it anyway. As for stock Lexus trannies....I don't know enough to advice one way or another. If you are concerned, get a window switch. It's a small price to pay for peace of mind.
As for the plugs: Go to the auto parts store and buy the cheaper version NON-IRIDIUM plug for you car. I would go a step further and get them 1 step colder. They say the rule of thumb is 1 step colder for every 50 shot of nitrous. The reason for the cheaper plug is that they have a wider electrode which in turn guards against the "blow out" of the spark sometimes related to thin (Iridium or plat) electrodes of our oem plugs supposedly caused by any "forced induction". I have used the cheaper wider electrode plugs in mine up to 2 steps colder w/o any problems. They end working out great because you will have to check your plugs more often for signs of detonation anyway. This way, using cheap plugs lets you throw them out and change them more often w/o it costing you an arm and a leg. The one draw back is that it will idle funny when it's cold if you use colder plugs. No biggie. BTW, you decrease the gap size not increase it. It's again to avoid the blow out mentioned above.
I have used both dry and wet setups. The wet setups are much better to use since they inject fuel at the same time and therefore are less likely to run LEAN. They do have a drawback. Depending on the length of the intake runner, the wet setup is said to create puddling. This puddling in turn is associated with the dangers of premature ignition. I personally have not seen this happen, but have read numerous articles mentioning that. Maybe its one of those "urban legends"...
Either way, the dry setup (if it's NOS brand) is going to require some kind of rise in fuel pressure for the additional fuel. That is most of the time done from one of the two solenoids in the system. The solenoid will pull vaccum, when the system engages, from the stock pressure regulator causing the system to momentarily get super rich which in turn compensates nicely with the added nitrous. At 75 shot, you should have no problems, but sometimes you have be careful not to go above your injectors duty cycle or the fuel pumps max volume. This is why I was mentioning the bigger fuel pump earlier. This is usually done because car makers put the smallest pump necessary to work stock. They didn't ever factor having to momentarily up the fuel volume considerably, so the stock pump peters out in the top end.
As for spraying during shifts, the window switch is very inexpensive. The added safety is worth the cost. I personally have never used because I had custom valve bodies on the auto's and therefore the shifts were almost instantaneous. So what little amount I sprayed while shifting was minimal. Besides my auto tranny is built so it could stand it anyway. As for stock Lexus trannies....I don't know enough to advice one way or another. If you are concerned, get a window switch. It's a small price to pay for peace of mind.
As for the plugs: Go to the auto parts store and buy the cheaper version NON-IRIDIUM plug for you car. I would go a step further and get them 1 step colder. They say the rule of thumb is 1 step colder for every 50 shot of nitrous. The reason for the cheaper plug is that they have a wider electrode which in turn guards against the "blow out" of the spark sometimes related to thin (Iridium or plat) electrodes of our oem plugs supposedly caused by any "forced induction". I have used the cheaper wider electrode plugs in mine up to 2 steps colder w/o any problems. They end working out great because you will have to check your plugs more often for signs of detonation anyway. This way, using cheap plugs lets you throw them out and change them more often w/o it costing you an arm and a leg. The one draw back is that it will idle funny when it's cold if you use colder plugs. No biggie. BTW, you decrease the gap size not increase it. It's again to avoid the blow out mentioned above.
I have used both dry and wet setups. The wet setups are much better to use since they inject fuel at the same time and therefore are less likely to run LEAN. They do have a drawback. Depending on the length of the intake runner, the wet setup is said to create puddling. This puddling in turn is associated with the dangers of premature ignition. I personally have not seen this happen, but have read numerous articles mentioning that. Maybe its one of those "urban legends"...
Either way, the dry setup (if it's NOS brand) is going to require some kind of rise in fuel pressure for the additional fuel. That is most of the time done from one of the two solenoids in the system. The solenoid will pull vaccum, when the system engages, from the stock pressure regulator causing the system to momentarily get super rich which in turn compensates nicely with the added nitrous. At 75 shot, you should have no problems, but sometimes you have be careful not to go above your injectors duty cycle or the fuel pumps max volume. This is why I was mentioning the bigger fuel pump earlier. This is usually done because car makers put the smallest pump necessary to work stock. They didn't ever factor having to momentarily up the fuel volume considerably, so the stock pump peters out in the top end.
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10-21-03, 09:53 AM
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OK so my shpping list just increased a little from just a bottle warmer and auto-valve.
Cheaper plugs huh? I guess I'll have to experiment.
Also, as far as that fuel pump goes, do you have a recommendation a particular one?
Window switch is definately on the list.
Cheaper plugs huh? I guess I'll have to experiment.
Also, as far as that fuel pump goes, do you have a recommendation a particular one?
Window switch is definately on the list.
10-21-03, 10:04 AM
#9
Lexus Test Driver
Originally posted by SilverLexo
OK so my shpping list just increased a little from just a bottle warmer and auto-valve.
Cheaper plugs huh? I guess I'll have to experiment.
Also, as far as that fuel pump goes, do you have a recommendation a particular one?
Window switch is definately on the list.
OK so my shpping list just increased a little from just a bottle warmer and auto-valve.
Cheaper plugs huh? I guess I'll have to experiment.
Also, as far as that fuel pump goes, do you have a recommendation a particular one?
Window switch is definately on the list.
Yep, cheaper in this case is better.
The only fuel pump I would ever recommend is the Walbro. They are very very reliable and have different kinds to suit your needs. I'm not sure which one you would need for the Lexus (I could tell you for Nissan) but I'm sure someone in this site has one they may be able to give you the part number off of. If you can't find anywhere to get it, let me know and I'll hook you up with the guy that I get mine from.
10-21-03, 10:17 AM
#10
Lexus Test Driver
As much as I'd hate to say it, EBAY is a good source for nitrous parts. You can find assorted jets, valves, heater, blanket, etc. cheap. As always, make sure you check out who you're buying from BEFORE you decide to bid.
I bought a lot of my parts from ebay when I first started out with nitrous. It's a good place to find all the possible choices available out there. Summit and Jeggs are also good sources.
I bought a lot of my parts from ebay when I first started out with nitrous. It's a good place to find all the possible choices available out there. Summit and Jeggs are also good sources.
10-21-03, 05:26 PM
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Tuning is a must!!!! I had my car dynoed today and on n.i.t.r.o.u.s (LOL) she was running wayyyy lean. I had no idea, I have been running this way for about 2 months now. The guys/gals at TPS dyno tuned my IS a little and changed some fuel jets and now is better, gained HP too! If used correctly, nitrous is a lot of fun!
10-21-03, 05:30 PM
#12
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Really? Is it a wetor dry setup? Have you upgraded your fuel pump? I'm sure it's set on WOT, but do you have a window switch?
Oh yeah, one more thing...how the heck is that window switch going to know when my lex wants to switch gears? Seems like it would have to be hooked up to the ecu somewhere?
Oh yeah, one more thing...how the heck is that window switch going to know when my lex wants to switch gears? Seems like it would have to be hooked up to the ecu somewhere?
10-21-03, 05:35 PM
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Mine is a wet kit. The WOT switch is activated by the pedal but the NOS kit is turned on my a on/off switch. I turn on the NOS kit, and next time I hammer it, the NOS is there. I am still using stock fuel pump at moment, but once the supercharger is on, no more.
10-21-03, 05:42 PM
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gotcha on that one.(that's what my remote valve will be for).
I'm just wondering about Nitrous flowing between shifts...doesn't the fuel slow down a bit while shifting in an auto? You probably don't have that problem because your Nitrous flows throught the injectors (fuel stops, nos stops). But with a dry setup, how can I be sure that the nitrous won't be waaay to lean during shift points?
I'm just wondering about Nitrous flowing between shifts...doesn't the fuel slow down a bit while shifting in an auto? You probably don't have that problem because your Nitrous flows throught the injectors (fuel stops, nos stops). But with a dry setup, how can I be sure that the nitrous won't be waaay to lean during shift points?
10-22-03, 03:12 AM
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I am a 5spd so I can't tell ya on this one. It is a WOT switch and will continue to spray fuel/nitrous while the pedal is to the floor. It will not lean out fuel or spray unless I take my foot off the pedal a wee bit and close the WOT switch.