sti lol

Trying to wrap my head around the way holley says to use their 3 ports. Teed together with a pressure sensor on the top of a gate. What is the reasoning behind using 2 teed together instead of just using one the way every other 3 port says... I'd like to use a 4 port but I also want to keep a nice holly plug and play for my efi.. can someone please give me the simple "tee them together because..." I'm using my pressure source as the compressor not co2..

svslow

This is the best way to run it

sti lol

That is a 2 port. The 3 port shows compressor into the bottom of the wg and the 2 3 ports teed off into the top with a dome sensor in the other top. Need to know why. I know ones to fill and one to vent but do 3 ports not have inlet, outlet and front vent? Curious why you need a designated vent 3 port?

svslow

The picture I posted about is the easiest way, in my opinion, to use a 3 port solenoid. In this configuration, the solenoid regulates how much pressure is sent to the top of the gate and the bottom port receives full compressor pressure. The differential across the two ports is what controls when the gate opens.

dburt86

iTrader: (2)

Every time i plumb one, i confuse myself and i literally have to blow into the solenoid to figure it out. Ive been doing this a long time, you would think id remember by now. Its emarassaing.

But in that configuration above, in the pic, the 3rd port is a vent to port 2 so when the solenoid is off, the upper port of the gate can vent out of port 3 because if it doesnt, it will trap pressure in the top of the wastegate, giving you inconsistent boost control every time you wack it.

dburt86

iTrader: (2)

The way you wanna run it for big boost is
pressure source to port 2
Bottom of gate to port 3
top of gate to port 1

A small hole in top of gate line to vent the pressure out (essentially what port 3 would do in the pic above)

svslow

Holley's 67 page instruction manual doesn't really seem to make it straight forward I'm sure.

stevieturbo

They are all using the same design of 3 port solenoid, just using it in different ways. And the image above is a 3 port solenoid, not a 2 port.

Why they feel the need to have a fill and vent solenoid when a single solenoid will do exactly the same job....is a mystery.

But if you dont understand all the differences, ( and all software configurations ) then just follow their instructions for the outcome you wish to achieve.

I guess the only one benefit of having two individual solenoids for fill/vent is it may be a little more efficient in terms of CO2 usage/wastage

sti lol

Thanks for chiming in gents! I'm also assuming the 2 3 port setup is more for co2 control than using the compressor for a pressure source. Seems like people follow that holly document with a really nice picture and can't really explain why. I always thought of a 3 port as in/ vent out the front and out to the wastegate top. 4 port controlling top and bottom of gate. I struggle to realize why you need a complete solenoid to vent when the original inlet solenoid has a vent built In. I'm hoping for some tune say guys to help and say "when I tune cars, it's simple with 2 because. .." rather than because holly page 67 says so...

I also have to do some co2 research as I have free access to tanks and fills. Just need to wrap my head around how simple people make it seem. Bottle/regulator and a hose to the solenoid.. guess you leave your regulator at a set amount (say 20 pounds) and tune the solenoid to use that ammo t of pressure to hold the dome down when needed...

93camaro_zzz

iTrader: (13)

Do you just not want to buy another 3 port sensor? Maybe it is just the way that Holley is actually programmed. Who knows.