boost drops at high rpm

[escortman]

i have a afm 4agze in my fx wiht a front mount and a honda pulley gets 7.5psi max at nite but at about 5500rpm hte boost drops back to about 6psi sometimes a little lower whys this?

[bluemaumau]

search abv mod

[bluemaumau]

too be fair tho ive read that thing a few times and still cant figure out how to do it

[escortman]

o rite cuz the guy i bought it off sed it wasnt runnign the abv or something

[escortman]

found hte thread and had a look but i cant tell which is which i have a foto of some hoses by inlet manifold could anyone take a look

[ae93_sx]

I don't think the abv mod would be effecting it in this case. My understanding is that the abv just stops ou from going over 8 or 9psi.

when my afm 4agze was supercharged it used to loose about 1psi high in the revs, i'm not sure what the cause was though, i had done the abv mod too.

[Chickenman]

Superchargers lose their efficiency at higher rev ranges, especially the smaller ones on 4agze's.

Also the engine is swallowing more air so the resistance that creates positive boost pressure is lessened and your boost gauge sees a drop.

And... as air is compressed it heats up and loses density, so when your sc is creating too much heat and the intercooler can't cool it you see a pressure drop. happens in standard turbo cars as well on warm days as the intercooler efficiency drops.



OR... They just run out of puff up there.

Simple and easy

[IH8TEC]

I don't think the abv mod would be effecting it in this case. My understanding is that the abv just stops ou from going over 8 or 9psi.

when my afm 4agze was supercharged it used to loose about 1psi high in the revs, i'm not sure what the cause was though, i had done the abv mod too.

mine used to gain about 1psi in the last after 6500rpm.

[crshbndct]

honda pulley?

[escortman]

yeh i know previous owner put it on siad it went form 6psi that the factory pulley gave to 7.5

[crnkin]

(turbo it)

[escortman]

yeh but i have to move the radiator and find a dump pipe for it

[crnkin]

(turbo)

[escortman]

ok jus realised i have no school anymore and dont start work till dec 11, looks like im gona turb nxt week, crnkin u up in aucks now? know anyone with spare dump pipe for the vf10

[crnkin]

yep i live in ellerslie

I have a vf10 dump pipe flange and an arc welder with your cars name writeen all over it

if your cars name is "warning, do now attempt to modify 15 amp plug to fit 10 amp household socket with an angle grinder"

[escortman]

o ok

lmao sounds about rite