The Stupid Engine Questions Thread

[DRAGGIN95]

I understand what you are aiming for, but my problem is volume, when you get on the gas hard those smaller lb/hr injector's aren't going to keep up with what the engine need's, a 350 nearly need's bigger injector's bone stock.

 

[barebones 1500]

Help me understand.
Smaller injector, higher pressure could provide same amount of fuel as larger injector low presser right?
If so than I would think the better atomization of fuel would help economy without sacrificing much, if any power.
Tell me where I', wrong. Just trying to understand.

it seems you would be doing alot of work just to get back to were you started. In my head, if you pump more fuel to smaller injectors to get the same amount then the atomization won't change. In theory it will run but i think you will do alot of work just to undo it.

 

[cdub]

a 350 nearly need's bigger injector's bone stock

Good point.
I am not sure how to calculate volume vs. pressure, but I did see a chart somewhere from a TBI performance site. If I can find it, I may see how much pressure is needed to to get a 4.3l or a 5.0l to flow as much as a 350.
What is the 350 injector rated at, how many lbs per hour of fuel? Is it 55# or 61# I have seen both specs.
I read the 4.3 is 45#/hour

 

[cdub]

if you pump more fuel to smaller injectors to get the same amount then the atomization won't change

Wouldn't the atomization be much better at 20 psi vs. 12psi that I have now? If I raise the pressure I have now, I believe I will get better atomization, (and performance) but poor fuel economy.

 

[barebones 1500]

Spraying fuel at a higher pressure will cause a finer mist and that would atomize better but volume would have to increase as well. increased volume would cause it to spray less so no real ground will be gained except for extra pressure on you system which will cause more problems over time.

 

[MOBS]

In my picturing what you're saying, I'd rather have lower pressure higher volume........think about the fuel spray, it sprays in a conical shape....when it's spraying at lower pressure the air grabs it and mixes well...at a higher pressure the gas would shoot thru the air and hit the sides of the tbi or would hit the throttle plates, or shoot straight down and hit the circular indentions in the plenum of the intake.....either which way it does it, I can only imagine that the gas would collect in one of those 3 places and the air-fuel atomization wouldn't occur very well, if at all. It'd be about as efficient as running your car by just pouring gas down the carb.

Ofcourse that's just how I pictured it could go wrong.


*Nevermind, I just noticed what barebones put....it makes sense, gahh, I don't wanna even think about this haha.

 

[cdub]

Thanks for the responses. It's nice to get a sanity check.

Guess I'll shelve this idea and find something else to tinker with.

~C

 

[chipper]

Need help 95 Suburban motor noise?

I have a 95 Suburban 1500SLT w/ a valve slap sound coming from the area of #1 cylinder. I put oil additive in & had stopped the noise, then it returned. More additives not quieting the sound. Is this the end of my motor or could it be something else?

 

[FastOrange]

I have a 95 Suburban 1500SLT w/ a valve slap sound coming from the area of #1 cylinder. I put oil additive in & had stopped the noise, then it returned. More additives not quieting the sound. Is this the end of my motor or could it be something else?

adjust rockers.

 

[chipper]

You have heard of this noise before and made the adjustment?? I'm hearing lots of possible reasons for the sounds. I give it a try...