Boost reference.

[kenhaw]

Hi Guys

Where do you connect the hoses for boost gauges, map sensor and other boost related things?
I have some installed in the hat because it seems the boost is biggest there compaired to the manifold.

[wicked68]

Hi Guys

Where do you connect the hoses for boost gauges, map sensor and other boost related things?
I have some installed in the hat because it seems the boost is biggest there compaired to the manifold.

I put everything on the back of the "hat" so that they run straight back through the firewall to my guages and computer.

[GetMore]

You want them all after the throttle blades. If there is a difference between the pressure in the manifold and the pressure in the hat I'd say you should go to the manifold, since it's what the engine sees.

[camcojb]

you want a boost gauge, timing retard box, wastegate(s) and controllers, surge valve, etc. below the throttle blades, not in the hat. The only line in the hat would be the line to the fuel pressure regulator or mechanical fuel pump if no regulator, on a blow through carb setup.

Jody

[kenhaw]

you want a boost gauge, timing retard box, wastegate(s) and controllers, surge valve, etc. below the throttle blades, not in the hat. The only line in the hat would be the line to the fuel pressure regulator or mechanical fuel pump if no regulator, on a blow through carb setup.

Jody

Ok, but why is there such a big difference in the levels of boost seen in the hat and below the throttleblades?

[camcojb]

Ok, but why is there such a big difference in the levels of boost seen in the hat and below the throttleblades?

because there's pressure on top of the throttle blades due to the blower spinning all the time. Problem is, that boost in the hat is vacuum in the engine at cruise and light throttle.

A diesel may go down the road cruising under boost, but not most any gas engine. All your timing retards, etc. need to see the condition the ENGINE is seeing, not the hat. If you hooked a timing retard to the hat for example, which may show 6 psi going down the road at a cruise, it would be pulling timing. You don't need the timing pulled the engine isn't in boost, just above the throttle blades is.

Another example would be with a water injection kit. You hook it up to the hat for reference and it may be injecting during cruise, because it would think the engine is in boost when it is not.

Anything related to the engine condition operation needs to be below the throttle blades, to see what the engine is seeing, not what the hat is seeing. The only critical reference line in the hat is for a blow through carb, and that goes to the fuel pressure regulator. You have to have that as the fuel bowls have pressure in them at a cruise as they're directly connected to the hat and above the throttle blades. If you have 6 psi of pressure in the bowls and the fuel pressure doesn't rise the same amount, your 7 psi of fuel pressure is now acting like 1 psi, as it takes 6 psi just to balance out and push past the pressure in the fuel bowl. So that line needs to relate directly to the hat and fuel pressure regulator, but nothing else goes in the hat (other than water injection if you choose to).

Jody

[kenhaw]

Thanks Jody

That explains everything loud and clearly.

[Tom Vogel]

Anything related to the engine condition operation needs to be below the throttle blades, to see what the engine is seeing, not what the hat is seeing. The only critical reference line in the hat is for a blow through carb, and that goes to the fuel pressure regulator.

Jody[/quote]

This is what Procharger says.