High Compression W/ N20 .... Good or bad
High Compression W/ N20 .... Good or bad
just wondering, when considiring to run nitrous on NA engine, will higher compression promote detonation, is lower compression desired in such applications, like a turbocharged engine? Also do pistons hold up to the pressure or aftermarket pistons are needed.
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WDRacing
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I'm not the most experienced with N2O, but I've built a few engines. N2O is extremely cold, which makes it less prone to detonation as long it has enough fuel mixed with it so as not to create a lean condition. As with any engine, your going to run into a point where your bottom end will start to weaken do to increased cylinder pressure. I'd say your rods would bend first. But one can never be sure. The best bet would be replace the rods and pistons at the same time.
I'd say the best thing would be to put your car on a dyno and slowly increase the N2O/Fuel while using a wideband O2 and accurate EGT sensor to monitor knock and so forth.
Don't forget you'll need to have your timing adjusted for N2O as well. I believe the correct ratio for a wet type system is 2 degree's retard for every 50HP of N2O. But you'd better ask the N2O manufacturer for the details.
Hope that helped some...
WD
I'd say the best thing would be to put your car on a dyno and slowly increase the N2O/Fuel while using a wideband O2 and accurate EGT sensor to monitor knock and so forth.
Don't forget you'll need to have your timing adjusted for N2O as well. I believe the correct ratio for a wet type system is 2 degree's retard for every 50HP of N2O. But you'd better ask the N2O manufacturer for the details.
Hope that helped some...
WD
some great information, but im wondering that if i plan to install a nitrous system on the engine, forged piston and rods are goin to be necessary to help it live a long life, but since the nitrous will have a more explosive reaction than gasoline, would it be best to use lower compression pistons or would it be just the same thing to use higher compression ones. I want the engine to be reliable.
then dont use nitrous at all. nitrous+reliable=false
unless you build it right, I dont think higher compression pistons and things would hurt, as long as you dont try to dump a ****-ton of n20 into the engine without proper tuning. I would get a nice adjustable setup, set it to maybe 30hp after you rebuild the engine and tune it from there.-chet
unless you build it right, I dont think higher compression pistons and things would hurt, as long as you dont try to dump a ****-ton of n20 into the engine without proper tuning. I would get a nice adjustable setup, set it to maybe 30hp after you rebuild the engine and tune it from there.-chet
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Scott McLellan
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Just curious, what makes N2O so "unreliable?" Seems like it would be more realistic because you could drive on just engine to get good gas milage and have the rocket power when you want it at the flip of a switch. As long as the engine is built and the Nos is controlled by some controller it would be just fine seems like. More horsepower=less reliable in all applications even turbo. There is a reason nitrous is considered to be the best "bang for the buck".....
"More horsepower=less reliable in all applications even turbo. There is a reason nitrous is considered to be the best "bang for the buck"....."
uh. negative, a well built turbo engine will last far longer than nitrous injected one. nitrous has a horrible tendancy to cause detonation, and cause odd engine problems after long use.
I know turbo can cause detonation, but Im talking about flip of the switch "kaboom" type stuff. nitrous is considered best bnag-for-buck because it is cheap HP. but its not reliable HP. turbos are.and who the hell gave you the idea that more HP means its less reliable, your on crack. look at the m5 V-8. that sucker will run for 80k and puts out 400hp. almost 3 times as much as most civics, or even 240's.-chetanything can break if you do it wrong, nitous is usually run very haphazardly to keep costs low(thus the 'bang for buck' you refer to). a good nitrous controll system costs about 1200 dollars or more, with tank, warmer, ECU plug in, switches, jets, and progressive FMU and Nitrous pressure regulators. without those, your literally flooding your engine with more oxygen(thats what it does) than its calibrated to take, causeing serious problems(detonation for example) since nitrous systems dont use any feed in to the ECU, MAF< etc, as a turbo system does.
uh. negative, a well built turbo engine will last far longer than nitrous injected one. nitrous has a horrible tendancy to cause detonation, and cause odd engine problems after long use.
I know turbo can cause detonation, but Im talking about flip of the switch "kaboom" type stuff. nitrous is considered best bnag-for-buck because it is cheap HP. but its not reliable HP. turbos are.and who the hell gave you the idea that more HP means its less reliable, your on crack. look at the m5 V-8. that sucker will run for 80k and puts out 400hp. almost 3 times as much as most civics, or even 240's.-chetanything can break if you do it wrong, nitous is usually run very haphazardly to keep costs low(thus the 'bang for buck' you refer to). a good nitrous controll system costs about 1200 dollars or more, with tank, warmer, ECU plug in, switches, jets, and progressive FMU and Nitrous pressure regulators. without those, your literally flooding your engine with more oxygen(thats what it does) than its calibrated to take, causeing serious problems(detonation for example) since nitrous systems dont use any feed in to the ECU, MAF< etc, as a turbo system does.
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WDRacing
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N2O can be used extremely safely, just the same as the any forced induction. You just have to use a quality kit. N2O has been around for years. There are tons of secrets...
My advice to you on reducing your CR would be this. Your not using N20 all the time. So your daily driving will go to crap if you lower your CR. Call the guys at NOS, they won't steer you the wrong way. I would suggest not going over 50hp without the use of a dyno. Oh, one tip I can think of. If the car starts to detonate, don't just add fuel. First reduce the amount of N2O then add fuel.
Make some phone calls and send some emails...
WD
My advice to you on reducing your CR would be this. Your not using N20 all the time. So your daily driving will go to crap if you lower your CR. Call the guys at NOS, they won't steer you the wrong way. I would suggest not going over 50hp without the use of a dyno. Oh, one tip I can think of. If the car starts to detonate, don't just add fuel. First reduce the amount of N2O then add fuel.
Make some phone calls and send some emails...
WD
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Scott McLellan
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For the original question about compression. Couldn't you just put in a little premium fuel and some octane booster for the nos, and use regular fuel (cheaper) for normal driving and keep normal compression? Just don't run a chip that advances the timing and maybe use something that retards the timing for the nos. Compression doesn't really matter with nitrous like it does with turbo. It's happy in any built engine that is, key words, properly built and tuned.
N20 work like Force Induction. Instead of increasing cylinder pressure, you increase the density of Oxygen of the intake air. up from 21% atmospheric air to 33% Nitrous Oxide ( 2 Nitrous, 1 Oxygen, -> 33% )
Since the oxygen is increase, you need to increase fuel to maintain proper Air/Fuel ratio. If not , detonation, pinging, knock will occur.
To be in safe side, you retard timing, increase fuel octane, use cooler plug to slow down the burn process/prevent detonation. You can also use more fuel to lower air/fuel ratio to 1. make intake air cooler ( less changes for detonation) 2. increase octane contain ( more fuel more octane )
Reducing Compression Ratio is one of the method to be in safe side for Nitrous Oxide, just like Force Induction.
If use regular fuel and some octane booster work that well, why not every racer use these method to increase 130+ octane ? And why Fuel company don't produce such Octane Booster and stop making premium gas ?
Before running Nitrous, make sure 1. engine is healthy ( hold good psi at compression test )2. DO NOT use plantinum spark plugs. High temperature in nitrous burning will fault the plugs.3. Use colder spark plugs. Nitrous Oxide Generate a lot of heat4. Use higher octane fuel if possible. To reduce killing detonation5. Retard timing. 1 - 3 degree depend on your application6. Working fuel system. Make sure your fuel filter and fuel pump is up and ready7. Take extra precaution. Graduately increase your nitrous application from small to big. start from 25 or 35 shot recommended. Check your spark plugs frequently for lean indicate.8. Get a Air/Fuel ration gauge ( not very accurate ) or EGT gauge ( not accurate if running too rich ) for safety measure against nitrous oxide use. If you have Wide-Band O2 sensor, that will work the best.9. Make sure you nozzle is at least 6 inches away from throttle body. And also make sure you nozzle is set at the center piping of your intake to ensure proper distrubution. Setting too far in or too far out will cause lean in certain cylinder due to how air flow in high RPM.
Running big shot or small shot have no different if you don't run it right. Detonation will still occur even at small shot.
Since the oxygen is increase, you need to increase fuel to maintain proper Air/Fuel ratio. If not , detonation, pinging, knock will occur.
To be in safe side, you retard timing, increase fuel octane, use cooler plug to slow down the burn process/prevent detonation. You can also use more fuel to lower air/fuel ratio to 1. make intake air cooler ( less changes for detonation) 2. increase octane contain ( more fuel more octane )
Reducing Compression Ratio is one of the method to be in safe side for Nitrous Oxide, just like Force Induction.
If use regular fuel and some octane booster work that well, why not every racer use these method to increase 130+ octane ? And why Fuel company don't produce such Octane Booster and stop making premium gas ?
Before running Nitrous, make sure 1. engine is healthy ( hold good psi at compression test )2. DO NOT use plantinum spark plugs. High temperature in nitrous burning will fault the plugs.3. Use colder spark plugs. Nitrous Oxide Generate a lot of heat4. Use higher octane fuel if possible. To reduce killing detonation5. Retard timing. 1 - 3 degree depend on your application6. Working fuel system. Make sure your fuel filter and fuel pump is up and ready7. Take extra precaution. Graduately increase your nitrous application from small to big. start from 25 or 35 shot recommended. Check your spark plugs frequently for lean indicate.8. Get a Air/Fuel ration gauge ( not very accurate ) or EGT gauge ( not accurate if running too rich ) for safety measure against nitrous oxide use. If you have Wide-Band O2 sensor, that will work the best.9. Make sure you nozzle is at least 6 inches away from throttle body. And also make sure you nozzle is set at the center piping of your intake to ensure proper distrubution. Setting too far in or too far out will cause lean in certain cylinder due to how air flow in high RPM.
Running big shot or small shot have no different if you don't run it right. Detonation will still occur even at small shot.
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C-Kwik
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This topic could go on forever. There are positives and negatives to everything. Both forced induction and Nitrous systems essentially bring more oxygen into the motor allowing more power to be made. Nitrous injects a cooler charge into the cylinder. Forced induction tends to be hotter. Fuel requirements are similar, and both can benefit from some quenching effects of running a little rich to avoid detonation. Timing is also an issue for both systems.
I have not looked into Nitrous a whole lot, but I speculate it may burn a mixture faster than atmospheric air that holds the same oxygen content since it won't have as much of a buffer. I haven't seen any actual data on this, so it's pure speculation. This could lead me to believe that there may be higher peak pressures in the cylinder, so that may cause parts to fail. But I would argue that it's likely detonation that causes most failures.
As I've said in another thread before, Compression loads do not cause fatigue. Tensile loads(pulling) contributes to fatigue. Not that rods can't fail, but it would either fail or it wouldn't. There's no inbetween just from more peak cylinder pressure. Tensile loads are determined by weight and acceleration(or deceleration) of the piston, particularly when it reaches TDC on the exhaust stroke since there is no compressive load to offset the tensile load.
The Key to adding power reliably on any motor is tuning. Detonation can cause pressures up to 10 times as much as a piston would normally see. This tends to be a leading cause of failures. Control the detonation and you will probably be fine.
I have not looked into Nitrous a whole lot, but I speculate it may burn a mixture faster than atmospheric air that holds the same oxygen content since it won't have as much of a buffer. I haven't seen any actual data on this, so it's pure speculation. This could lead me to believe that there may be higher peak pressures in the cylinder, so that may cause parts to fail. But I would argue that it's likely detonation that causes most failures.
As I've said in another thread before, Compression loads do not cause fatigue. Tensile loads(pulling) contributes to fatigue. Not that rods can't fail, but it would either fail or it wouldn't. There's no inbetween just from more peak cylinder pressure. Tensile loads are determined by weight and acceleration(or deceleration) of the piston, particularly when it reaches TDC on the exhaust stroke since there is no compressive load to offset the tensile load.
The Key to adding power reliably on any motor is tuning. Detonation can cause pressures up to 10 times as much as a piston would normally see. This tends to be a leading cause of failures. Control the detonation and you will probably be fine.
nos=reliablenos not tuned correctly= broken engine
nos is very reliable..and great..if you tune it correctly...i used a 75 shot for 3 years and 15+ bottles on a stock sohc motor...NO PROBLEMS AT ALL....you must install and tune the nos correctly...thats all....as far as a power adder its great...punches much harder than a turbo..
nos is very reliable..and great..if you tune it correctly...i used a 75 shot for 3 years and 15+ bottles on a stock sohc motor...NO PROBLEMS AT ALL....you must install and tune the nos correctly...thats all....as far as a power adder its great...punches much harder than a turbo..
Exar-Kun wrote:then dont use nitrous at all. nitrous+reliable=false
unless you build it right, I dont think higher compression pistons and things would hurt, as long as you dont try to dump a ****-ton of n20 into the engine without proper tuning. I would get a nice adjustable setup, set it to maybe 30hp after you rebuild the engine and tune it from there.-chet