KlubFoot Posted January 4, 2005 Report Share Posted January 4, 2005 How does compression ratio affect the amount of nitrous you can use? I know with a turbo or supercharger, the lower the CR the less chances you have of detonation. What about nitrous? Same rules apply or is it different? Also, I've heard hypereutectic pistons can be better then forged pistons in a nitrous application, I don't see what the sense is in that assumption, but I guess it doesn't hurt to ask. Thanks for your responses. Taran Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted January 4, 2005 Report Share Posted January 4, 2005 forged is always better it has more detonation resistance. nitrous is a little closer to naturally aspirated becuase the extra oxygen and fuel are generally just sucked into the motor throught the throttle body. a higher compression ratio will help not hurt with nitrous Quote Link to comment Share on other sites More sharing options...
Razorback Posted January 4, 2005 Report Share Posted January 4, 2005 nitrous likes compression boost hates compression I had a ~10.5:1 CR motor when I ran a 100/150 shot regularly and had no issues. My boosted motor has ~9.75:1 compression. Quote Link to comment Share on other sites More sharing options...
JaSSon Posted January 4, 2005 Report Share Posted January 4, 2005 All you need to know is this: Spray it until it hydrolocks, then back it out just a tiny bit. Quote Link to comment Share on other sites More sharing options...
desperado Posted January 4, 2005 Report Share Posted January 4, 2005 Gee Jason, I wonder where you heard that one???? But I think is was you can do what ever to rice mobile, spray the fucker till it hydrolocks, I will still beat you. Or something to that effect. Quote Link to comment Share on other sites More sharing options...
Buckeye1647545503 Posted January 4, 2005 Report Share Posted January 4, 2005 Call Hensler racing he knows he shit with nitrous. He runs a sprayed car in the NMRA Quote Link to comment Share on other sites More sharing options...
Nate1647545505 Posted January 5, 2005 Report Share Posted January 5, 2005 Originally posted by Razorback: nitrous likes compression boost hates compression I had a ~10.5:1 CR motor when I ran a 100/150 shot regularly and had no issues. My boosted motor has ~9.75:1 compression.Both of your situations don't like compression, they just are differant. Your C/R is lowered because of the marginally larger heat in the intake charge. We all know that when you compress air, you cannot keep it the same temp, with compression, the charge gets hotter. Nitrous, however, is a gas under 900-1xxx psi, and it delivers a more dense charge, at -175 degrees F. This is why you can take an almost stock LS or modular motor and hit it with such a big shot. The motor is large and has a low hp/liter output, the motor is more tolerant to detonation and pre-ignition. Nitrous is really nothing more than cold boost. You have more density in a cylinder when your under spray, creating more power. It basically should be treated like a blown car, except in the fact you have more of an area to work with, regarding timing and tuning thanks to the colder temps vs blown or turbo. A motor can only handle X amount cyl pressure before something lets go. If your not planning on building the motor around the bottle, look into the tuning aspect, it will keep the motor together, and give you the most bang for the buck. [ 05. January 2005, 01:18 PM: Message edited by: Deals On Wheels ] Quote Link to comment Share on other sites More sharing options...
OGRE Posted January 5, 2005 Report Share Posted January 5, 2005 Originally posted by Gas,Grass,or Ass: forged is always better it has more detonation resistance. nitrous is a little closer to naturally aspirated becuase the extra oxygen and fuel are generally just sucked into the motor throught the throttle body. a higher compression ratio will help not hurt with nitrous Many people lump engines into two catigories, N/A (natually aspirated) or PA (power adder). Aspirate means to inhale when By definition N2O actually fits under both catigories. Aspiration refers to how air enters the engine, not what is contained in it. N20 is not "forced" into the car (typically) so it is not boost (even though it does have an expanding effect when entering the engine because of heat) Although so does air, only on a smaller scale due to the fact that air isnt entering at the super-cold temps that N2O does. It is widley accepted that N2O is not Natually aspirated throughout racing, and many automotive people but the actual meanings of the word is different to what has been accepted. Quote Link to comment Share on other sites More sharing options...
Razorback Posted January 5, 2005 Report Share Posted January 5, 2005 Your C/R is lowered because of the marginally larger heat in the intake charge. We all know that when you compress air, you cannot keep it the same temp, with compression, the charge gets hotter.No, it's lowered because I have 5.2cc dished pistons in there now instead of flat tops. Nitrous, however, is a gas under 900-1xxx psi, and it delivers a more dense charge, at -175 degrees F.You are correct, nitrous oxide is at approximately -175 degrees F. This is why nitrous likes compression -- it provides its own intercooling. Thank you for defining why nitrous likes compression -- this is probably why the majority of built race cars for nitrous run 11:1+ compression ratios and boosted cars aim for far lower compression ratios (my 9.75:1 CR in my Cobra motor would be considered high by many individuals for a non-intercooled, boosted setup). Quote Link to comment Share on other sites More sharing options...
Nate1647545505 Posted January 5, 2005 Report Share Posted January 5, 2005 Originally posted by Razorback: No, it's lowered because I have 5.2cc dished pistons in there now instead of flat tops. You are correct, nitrous oxide is at approximately -175 degrees F. This is why nitrous likes compression -- it provides its own intercooling. Thank you for defining why nitrous likes compression -- this is probably why the majority of built race cars for nitrous run 11:1+ compression ratios and boosted cars aim for far lower compression ratios (my 9.75:1 CR in my Cobra motor would be considered high by many individuals for a non-intercooled, boosted setup). It is not just limited to C/R... Try spraying a high compression motor, with low displacement...What will happen? Try taking an s2000 and throwing a 150 shot on it, what will happen? The motor has a high output per litre, if it detonates, its toast. Take your 4.6 and throw a 150 shot on it, you can relative speaking, have safe power. You also have fogred dished pistons...you have more resitance to detonation. All cars work under some detonation, just the size and design of the motor determine when the motor goes kablewy. Compare appllees with applees and oranges with oranges. Full built race cars are that,FULL BUILT. I'm not arguing the fact that you can run a higher compression with nitrous, I'm arguing it has ALOT to do with size and output of the motor. A stock bottom end can only take so much heat and pressure before it goes pop, this is why FI needs lower compression than spray. I think I'm repeating myself here or something. When I said "we all know..." I meant that as, its a common thing, and not as a personal attack. I'm probably making this out than much more than it needs to be. Also, I haven't seen your car in the Devry parking lot at all, are still going there? Quote Link to comment Share on other sites More sharing options...
Nitrousbird Posted January 5, 2005 Report Share Posted January 5, 2005 Originally posted by Shrek: N20 is not "forced" into the carYou don't consider something under 1000psi of pressure being "forced" into the motor?? Of course nitrous isn't considered forced induction, it is being forced into the motor. Quote Link to comment Share on other sites More sharing options...
Razorback Posted January 5, 2005 Report Share Posted January 5, 2005 Originally posted by Deals On Wheels: It is not just limited to C/R... Try spraying a high compression motor, with low displacement...What will happen? Try taking an s2000 and throwing a 150 shot on it, what will happen? The motor has a high output per litre, if it detonates, its toast. Take your 4.6 and throw a 150 shot on it, you can relative speaking, have safe power. You also have fogred dished pistons...you have more resitance to detonation. All cars work under some detonation, just the size and design of the motor determine when the motor goes kablewy. Compare appllees with applees and oranges with oranges. Full built race cars are that,FULL BUILT. I'm not arguing the fact that you can run a higher compression with nitrous, I'm arguing it has ALOT to do with size and output of the motor. A stock bottom end can only take so much heat and pressure before it goes pop, this is why FI needs lower compression than spray. I think I'm repeating myself here or something. When I said "we all know..." I meant that as, its a common thing, and not as a personal attack. I'm probably making this out than much more than it needs to be. Also, I haven't seen your car in the Devry parking lot at all, are still going there?That's fine, you can argue that about size and out put of the motor -- kinda common sense. Probably why the Honda Civics I see at the track never run more than a 55-75 shot. Common sense -- most of the time anyway unless you get a full blown ricer playing with nitrous. smile.gif And I never had forged pistons with nitrous on my old motor w/ 10.5:1 CR -- flat top stockers with the 150 shot. smile.gif Yeah I think it's being blown up a bit. I think you and I are on the same page, just have a different way of calling the sky blue. And yes, I'm finishing up my second degree at DeVry. When I finish it up this year in June I will have gone for just slightly over 4 years. I only drive my car when the weather is good, otherwise I drive a beater -- needless to say I've driven my car about twice in the last 3 weeks. I also park my car out in BFE -- I park the beaters a bit closer. What do you drive? I'll try to keep an eye out for ya. Quote Link to comment Share on other sites More sharing options...
Nate1647545505 Posted January 5, 2005 Report Share Posted January 5, 2005 Black GTP, its all stock on the outside so it kind of blends in... It doesn't have a Devry sticker though..What degrees are you working on, worked on? Quote Link to comment Share on other sites More sharing options...
Razorback Posted January 5, 2005 Report Share Posted January 5, 2005 Originally posted by Deals On Wheels: Black GTP, its all stock on the outside so it kind of blends in... It doesn't have a Devry sticker though..What degrees are you working on, worked on?I have the ECT degree (Electronics & Computer Tech), and I'm finishing up the BTM (Bachelor's in Technical Management). I put my sticker on the rear windshield. I don't recall seeing your car though. I go at night though too, work during the day. Quote Link to comment Share on other sites More sharing options...
Nate1647545505 Posted January 5, 2005 Report Share Posted January 5, 2005 Originally posted by Razorback: I have the ECT degree (Electronics & Computer Tech), and I'm finishing up the BTM (Bachelor's in Technical Management). I put my sticker on the rear windshield. I don't recall seeing your car though. I go at night though too, work during the day.Ah, I go in the mornings for EET. Sometime's I'm there working on something though... rock on. Quote Link to comment Share on other sites More sharing options...
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