im with u i cant understand why would use high compression with nos but low compression for boost!!!!

 

I think the n2o can tolerate a little more compression because of the heat that it removes from the engine. A supercharger loads the crank down and a turbo loads up the exhaust which both increase heat in the engine/cylinder. The IATs go up most of the time with forced induction also which increases the chances for detonation. Here is a good article I found if you want to do more reading http://www.aircooled.net/gnrlsite/re.../n2otheory.htm

 

Great reading ^^ thanks Henry!

 

But....... But....... A butt turbo lover couldn't be right?

 

Here's the thing: You make more power from the equivalent amount of boost than you do the equivalent amount of compression. This is because of Boyles law (specifically the pressure law that gives us a linear increase in power for every atmosphere of boost -- e.g. for every atmosphere of boost we add to the engine, we add the equivalent of the same amount of cubic inches at ambient atmosphere -- so a 6.0L engine running at 2 atmospheres *of boost* is the equivalent to an 18.0L engine) So, by going lower compression to accomodate more boost before you see detonation, you are able to add more power than high compression (which does not have a huge linear add, but has a fractional add to hp).

Some pretend numbers to illustrate the point.

Say a 6.0L at 10:1 CR can make 350 hp and support 10psi of boost max. Let's say that's worth 150hp from the 2/3 of an atmosphere. That's 500hp.

Say a 6.0L with 8:1 CR makes 300hp but can support 28psi of boost. It's likely that the 28psi generates some like 400hp. That's 700hp.

The same comparison with a 150 shot of n2o.

6.0L at 10:1 = 350hp, and let's say the n2o is worht 175 actual hp = 525hp.
6.0L at 8:1 = 300hp, and say the n20 is worth 150 here, thats 450hp.

Of course, you could run more than a 150 shot on the 8:1 engine I'd think, but I'm not the n2o expert.

 

That makes sense. During the combustion process nitrous and boost are a lot alike. But out side the cylinder, affect the engine differently...

 

where did the refernce of 33 percent more oxygen come from on the first page. Says something about 33 percent more oxygen, trev.

 

Nitrous has/is 33% oxygen.. the atmosphere has around 20.9% oxygen. that why nitrous is so potent. you get to add more fuel to the mix at 33%. more fuel, more power.....

 

There are 3 molecules grouped together in n2o. Two nitrogens and one oxygen. 1/3 of the n2o molecule is oxygen, 33%.

 

woops, i read that backwards. I understand n2o is two parts nitrogen. From what i read i thought it was implied there was 2 parts oxygen, and i was like that not right. My bad.. back on subject.....