^

 

nitrous likes a lot of cylinder pressure, lots of seperation gives you that

 

In a force induction motor I know if there is too much overlap the pressure can escape out the exhaust valve, is it the same with n2o? Only other way I see pressure loss is from the exhaust valve opening too early. Are either of those the case?

 

More cylinder pressure.... does that mean that nitrous motors like more compression?


-Nick
94 Z28, 6 speed

 

yes

 

Really? So that means my 12.5:1 compression on the stroker I'm building would be better than 10.5:1? Could someone explain this to me, I dont' really understand why...

Thanks
-Nick
94 Z28, 6 Speed

 

from all the motors ive built in the past id say thats wrong. nitrous is not a forced induction but it does work better with a lower compression motor. if you slam i 150 shot into a 12.5:1 motor that is not very well equiped...... im just glad its not mine

 

Compression will help any motor. It has nothing to do with how much nitrous you can run in the motor. If you are going to run lots of nitrous with high compression, you just need to make sure you are using the proper fuel, and the timing is correct. The more compression, to an extent, the more hp your motor will make. Lobe seperation angles dont have to be wide for a nitrous application, but that is the latest fad. What they are trying to do is open the exhaust valve a little later, to allow more burn. When you start running high nitrous levels, you will learn that over lap is actually a good thing, and can help you in more then 1 way. It doesnt hurt to blow a little nitrous out the exhaust on overlap, it helps cool off the piston, and clean out hte combustion chamber of any unburnt fuel, or exhaust. The valve timing and events are really what you need to look at when choosing a cam. More lobe seperation isnt going to give you it all the time.

 

i just had the figures the other day about compression. you lose 4% per cc. is it really worth it? you run a 150 shot on a 12.5:1 motor thats already making serious heat,and now your just adding to the burn. you gonna melt something. espicially on a stock motor which i think has composit pistons. go with forged pistons and a little lower compression, its a lot safer and a lot easier on the motor. thats just my opinion

 

Heat is HP. I didnt think the guy was talking about a stock motor, anyways, the compression "heat" isnt what melts parts. A severely lean nitrous injection, along with detonation, is what makes a "blow torch" effect, and cuts right through the heads or pistons. Keep the detonation under control, and the nitrous tune right, and the compression will only help you out.

 

So you're saying that my setup will be fine assuming we do a special tune for running nitrous, and use the right grade fuel? I plan to run 106 octane unleaded anyways.... so that shouldn't be an issue.

BTW. The cam I'm getting has just under 112 lsa.


Thanks
-Nick

 

Like mentioned earlier you should match your ignition advance to the amount of N2O you are running to eliminate detonation. Also it is a good idea to tune with a wide band O2 sensor or EGT's to make sure you are not getting too lean.

Where have you found 106 octane unleaded?

 

Oh, sorry, I guess the highest I've found is 100 and 104. Here are the links...

76 Racing fuels

Sunoco racing fuels


-Nick

 

Thanks Agent. The highest I have ever seen is 100. Looks like I will be trying out the Sunoco when running the spray.