i ran a search and couldnt get a very detailed answer. i was curious if you could run 15+psi of boost on pump gas, how much of a factor does octane play with f/i applications, i'm sure with sufficient tuning it isnt as much of a problem.

 

It depends on which motor you are running. b18's have safely put out 450whp on pump gas whereas H series motors tend to promote problems on pump gas above 350whp. Here is a little bit of information on MSBC which is basically the saferange on how much power a motor can run on a certain octane.

"MSBC stands for Mean specific brake consumption or you can also call it Brake Specific Fuel Consumption (BSFC). This term is basically the ratio of the engine fuel consumption to the engine power output (as measured at the flywheel). BSFC has units of grams of fuel per kilowatt-hour (g/kWh) or pounds mass of fuel per brake horsepower-hour (lb/bhp-hr). BSFC is a measure of engine efficiency.

The H-series engines are less efficient than b-series. This means you need to run higher octane to sustain detonation." - boostedhybrid

The MSBC depends on factors such as combustion chamber design, the material of the head, head flow, etc etc.

 

"MSBC stands for Mean specific brake consumption or you can also call it Brake Specific Fuel Consumption (BSFC). This term is basically the ratio of the engine fuel consumption to the engine power output (as measured at the flywheel). BSFC has units of grams of fuel per kilowatt-hour (g/kWh) or pounds mass of fuel per brake horsepower-hour (lb/bhp-hr). BSFC is a measure of engine efficiency. "

bump for confusing me

 

It means this:

B series motors can get away with more power and less octane then an H series motor will.

 

I got that much but the (g/kwh) MSBC (BSFC) (lb/bhp-hr) all this is confusing to me.

thanks explaning it I just thought that it was cool becuase I haven't ben that lost in a thread in a wile!!!!!!!!!!

 

15psi is kind of missleading. What size turbo? What engine. He's exactly right with the calculations so what you need to look at is

1. What is the expected WHP at 15psi
2. What engine.

If 15psi fits in the calc then go for it with proper tuning. If not don't push your luck.

 

when i said 15+psi it was basically a ball park figure
for instance i would hope for 350+ hp to the wheels @15psi
also, how much trouble are you asking for running 93 octane on that kind of power
as long as you have it tuned right, is it rough on the engine?

turbo:planning on sc61
injectors: 550cc(maybe larger)
engine:b18b

thanks for the help

 

You should be able to get 350 whp on pump gas. That block is fairly stout. In order to do that you will need a good fuel management setup though. Otherwise your playing with fire. 350 whp is doable though.