How can I measure the supply fuel pressure and what actual fuel pressure the injectors are seeing?

 

Is the regulator before or after the TBI injectors?

 

Yo dude. The regulator works kinda like this I think: The spring pushes down over a section of line that goes to the return line. The tigher it's pushed down, the less fuel can get through. The remaining fuel has to be pushed through the injectors. So actually, in theory, the regulator is on the return line, if you think about it. Then again I am abandoning TBI so I don't know for sure. It's also been a long time since I dismantled a TBI.


But long story short, if you put a fuel pressure guage into the supply line, you'd be measuring the same pressure the injectors are seeing. Think of how pressure works... It's basically a driving force behind it. If there's a leak/hole/valve then the pressure doesn't have a chance to build as high (ie if you opened up the return line as much as it could go, the pressure in the supply line would drop because it's moving through easier).


hit me up on aim and I can try to explain more

 

This is what I have always thought as well, but when speaking with NOS about why they recommend 15-20 psi of fuel pressure for my nitrous kit, when the stock pressure is only 9-13 psi, I was told the supply pressure and injector pressure is different.

 

the stock fuel pump only does about 15-16psi though. hmm

 

If this is true, their recommendations make no sense at all to me. They told me if I put in a high flow fuel pump I would have to put in a smaller fuel jet for the increased line pressure, because as I said before, they claim the injector pressure and line pressure is different. I was also told the stock pump should be plenty. I'm starting to think that both people I talked to didn't have a clue what they were spewing out.

 

I'm pretty sure that the pressure on the injector would be the same as whats in the supply line... otherwise why the hell would people bother with fuel pressure guages???

 

When I get over this virus, I'm going to call NOS again and try to find someone who knows what the hell they are talking about. ****, now I'm scared the jetting for the 150 shot might not even be correct.