xfactor_pitbulls

iTrader: (16)

I looked through J-rods formula thread and online alittle, cant find what I am looking for. For a 93 octane stoich value what percentage increase and decrease of density will be seen from a constant say 12:1 AFR by temperature? Any help would be appreciated.

crazydavez28

iTrader: (5)

ideal gas law. you'll have to calculate an m and R for that specific mixture i'm assuming that may be a hang-up in the process.

PV=mRT

but you probably want

P= Density*(R/M)*T
Again you'll need the specific R and M for the mixture

justoyz2

Density? What is your end result. I think you are trying to determine what A/F you will have with 12 to 1 compression while using 93 Oct fuel?

If this is your true question, you can only answer is you are in one specific location and the weather condition stay exactly as it is when you capture your first reading.

Dew point, humidity, elevation and temperture determines the A/F at a given moment in time.

I have a closed loop system that manages my A/F ratio via dwell time thru my injectors.
It changes so fast it's unreal.....

To help you, please provide what result you are looking for.......

xfactor_pitbulls

iTrader: (16)

No, if you read my original post, its says based on a constant air/fuel of 12:1. What I am saying has nothing to do with compression. It has to do with exhaust flow and density charateristics relative to area of exhaust. For instance; your exhaust leaving your header/manifold is lets just say 1000* F. By the time that exhaust reaches your exhaust tip (if at the rear of a 10' run) it may only be 250* F. While the temperature cools drastically the volume is also contracting uniformly with the drop in temperature. Another example; you hang two turbos off a turbo manifold just off the engine and they spools many times more efficiently than the guys putting them in the rear of the car. Which is why they are always coating and wrapping the hell out of the hot side pipes to try and keep temperature (or density). Is that more clear?