PowerKraus
Enthusiast
I've been running nitrous since when TBI motors were 'IT" and SFI was but a dream (pre-Grand National) nevertheless, I continue to educate my noodle by reading various theories, application, and tune tune tune it on my motors. Very often I see inquiries about window switch settings, cam selection, and pro/con of head work. I am posting this information as some may enjoy reading the reasons behind the specific answers provided by this forum. So print this out and read; it is of sufficient length that one can enjoy while taking care of business in thine Throne Room !
Do NOT set your Window Switch to 'start' at a 'low' rpm level.
Nitrous flow remains constant no matter what rpm the engine is running. At lower speeds there is more time for the nitrous to fill the cylinders, so you get more nitrous in the cylinders at low rpms; at a disproportionate rate when compared to predicted RWHP at higher rpms and on 'average."
Dr. Good Head
First the INTAKE -At the proper temperature and pressure, much of the Nitrox you inject is in liquid form. Larger intake ports 'slow' the travel time and allows the nitrous to turn to a gas and reduce the amount of normally aspirated power; the nitrous takes up more room, so there will be less room for air, reducing volumetric efficiency. Also, no need for increased intake duration or a very high lift, so the intake side of the cam does not need to materially differ between that of a NA motor and that of Nitrox.
Then the EXHAUSTING Details - The extra power results in additional exhaust gas volume; extra volume you need to displace. Generally, the 'economics' (that is more $ dollars for you in Rio Linda Florida) of making the exhaust valve large enough (and subsequent unshrouding of the larger valve) is not a viable choice; it is best to look for a dual pattern cam with longer exhaust duration. Opening the valve earlier will help by getting the valve open more and bleeding off some pressure before the piston starts moving up the bore. This does eat into the power stroke, but more power is freed up than would be made by holding it closed longer. Closing the exhaust valve a little earlier helps. As for specs, look for 112-116° lobe separations and keep the intake timing the same, you must install the cam advanced, usually 6-8° advanced (open the valves earlier, and close'm earlier). The good thing about this is that advancing a cam will bring more low-end when running without the nitrous and the wider lobe centre angle will also help idle and vacuum. Also, in keeping with stock exhaust valve sizing, when using Nitrox, you can bet the exhaust valves of a nitrous engine are almost always too small. So with the increased pressure, you want the best flow from the 'git go', so low lift exhaust flow should be your number one concern.
I cannot take credit for the information; I've sourced it, over the years, from various sites, interviews, and conversations with some of the gurus of Nitrous, including Mike Thermos, John @ NX, John Lingenfelter (my early LSx days) and Corkey Bell (Grand National infancy stage in 1986). But as you know, neither real 'fans' of nitrous, but highly knowledgable), and along with others.
__________________
2002 GTS - VECII (Cockpit Mount), fresh air, "Nitrox", bullet exhaust.
[email protected]
Do NOT set your Window Switch to 'start' at a 'low' rpm level.
Nitrous flow remains constant no matter what rpm the engine is running. At lower speeds there is more time for the nitrous to fill the cylinders, so you get more nitrous in the cylinders at low rpms; at a disproportionate rate when compared to predicted RWHP at higher rpms and on 'average."
Dr. Good Head
First the INTAKE -At the proper temperature and pressure, much of the Nitrox you inject is in liquid form. Larger intake ports 'slow' the travel time and allows the nitrous to turn to a gas and reduce the amount of normally aspirated power; the nitrous takes up more room, so there will be less room for air, reducing volumetric efficiency. Also, no need for increased intake duration or a very high lift, so the intake side of the cam does not need to materially differ between that of a NA motor and that of Nitrox.
Then the EXHAUSTING Details - The extra power results in additional exhaust gas volume; extra volume you need to displace. Generally, the 'economics' (that is more $ dollars for you in Rio Linda Florida) of making the exhaust valve large enough (and subsequent unshrouding of the larger valve) is not a viable choice; it is best to look for a dual pattern cam with longer exhaust duration. Opening the valve earlier will help by getting the valve open more and bleeding off some pressure before the piston starts moving up the bore. This does eat into the power stroke, but more power is freed up than would be made by holding it closed longer. Closing the exhaust valve a little earlier helps. As for specs, look for 112-116° lobe separations and keep the intake timing the same, you must install the cam advanced, usually 6-8° advanced (open the valves earlier, and close'm earlier). The good thing about this is that advancing a cam will bring more low-end when running without the nitrous and the wider lobe centre angle will also help idle and vacuum. Also, in keeping with stock exhaust valve sizing, when using Nitrox, you can bet the exhaust valves of a nitrous engine are almost always too small. So with the increased pressure, you want the best flow from the 'git go', so low lift exhaust flow should be your number one concern.
I cannot take credit for the information; I've sourced it, over the years, from various sites, interviews, and conversations with some of the gurus of Nitrous, including Mike Thermos, John @ NX, John Lingenfelter (my early LSx days) and Corkey Bell (Grand National infancy stage in 1986). But as you know, neither real 'fans' of nitrous, but highly knowledgable), and along with others.
__________________
2002 GTS - VECII (Cockpit Mount), fresh air, "Nitrox", bullet exhaust.
[email protected]
