I know it sounds stupid, and it probably is overly simple but ...

Seriously, what is it about spraying, that makes you have to pull timing? I know it can detonate, very violently, but the reason?

I was thinking about it today at work, I mean I know you should pull a degree ortwo for every 50 extra HP you spray, but the cooling effect of nitrous, I thought, would conteract have all the extra volume of air/fuuel to compress in the combustion chamber. Maybe it doesnt though

Apparently it helps some though as N20 cars can run a couple more degrees of timing than a FI car does. Or at least it seems like it.

 

It is due to the increase in cylinder pressure....the more A/F mixture you force into the combustion chamber the higher the rick of detonation.

 

The main reason you need to pull timing is that nitrous dramatically increases the burn rate of the fuel. You want to try and have everything burned by about 15-17 degrees after TDC. So as you add more and more nitrous the added oxygen being released speeds the burn rate up. Increased cylinder pressure can generate more heat which can lead to preignition which can cause detonation. So even if you could get enough octane to handle the amount of cylinder pressure you are generating you would still need to retard the timing to make sure that you aren't generating peak cylinder pressure too soon in the cycle.

 

Great answer....

 

Thats exactly the kind of awnser I was looking for. Thanks I appriciate.

 

verry good answer