where do i put the vac hose from a dump valve?

[rx7-mark]

Hi. i have just bought a bailey dump valve to replace my quiet hks one and as i took the hks off i noticed the small vac hose wasnt connected to anything on the engine which could have been making it quiet in the first place. It was just dangling down between some other pipes.

I have fitted the bailey one but it sounds exactly the same as the hks so im guessing it has something to do with the vac hose.

I now have a problem in knowing where to put the new vac hose from the bailey valve.  :confused:

Any help would be appreciated.  :cheers

[rx7veilside]

u need to find where the vac hose previously attatched as this will be leaking vac and boost..for the new bailey just find one of the pipes from the upper inlet manifold that sees both neg vac and positive and tee into it..fyi the vailey dump valve wont open and close unless the vac line is attatched..u have got the single piston bailey have u..it just has a black slleve that opens under vac and closes on positive press

[Ricco_04]

If I am reading your post right then this is where the other end of your pipe would be going.  I also guess that they sound the same cause this pipe is what tells the dump valve to vent.

[rx7-mark]

Yes m8 it is the single piston valve.
I have tried it where you have it on the pic. I have my boost gauge t\'d into this aswell but when i put it there it seemed to be really quiet.
I will have another look when it stops raining.
Thanks for your help guys.

[rx7-mark]

Right. I have just put it on where you have on the pic and the valve is now open, It closes when i rev so i know its working as it should, The only problem i have got now is when i change gear i dont get the swoooosh i should be.

I cant see a adjuster on the valve so i guess im not going to get that noise.

Thanks for your help guys.

[rx7veilside]

dont understand at all.i have the bailey and it is def loud enough.what boost are u running and have u made sure there are no other vac pipes off..do  have a boost gge what is the vac reading on idle..just using ur finger to adjust throttle rev to about 4000rpm and let off with ur finger u shd get the ptsshh sound..valve should be closed when revving and open on lift off.if it is doing this then u must be getting the noise.it will be louder on boost as reving when stationary will not produce any more than atmo pressure not positive pressure

[rx7-mark]

It is a standard engine apart from a apexi induction kit. It is running at 10-12 psi. On idle the boost gauge says -20 psi.


I have just noticed a pipe off but i have no idea where it goes, I cant see anywhere on the engine it will go. I think i will have a look at another rex when i see one this afternoon and see where that pipe goes.  The pipe was hiding under the induction kit so i didnt see it until i started really having a look underneath.

[rx7veilside]

with a induction kit and bailey u shd be getting a noticeable sound definatly..there must be another reason for not getting the noise..u say on idle it is reading -20.this is a very low reading..i dont thing negative pressure is measured in psi..my defi reads -5 to -6 on idle.i think u have a pipe off somewhere

[rx7veilside]

i think u must be loosing pressure before it reaches the dump valve hence no noise.hunt around using ur finger for any pipe that is under vacuam when engine is running

[antnicuk]

have you got it on the primary or secondary turbo?,  you should have it on the primary if i remember correctly.  If its on the 2nd, it wont woosh unless you doing high revs

[rx7-mark]

i have just seen another rex and the pipe i have loose goes to the charge relief valve on the other car and his dump valve is on the pipe i have the charge relief valve on so i have a feeling i have it on the wrong turbo.

I have just given mine a run and it does dump on the second turbo (above 4500 rpm)

Does anyone live near me that has a similar set up so i can see the difference

I am going to try and connect this pipe up somewhere by t pieceing it in.

[antnicuk]

from memory,  there are 2 pipes, with 2 stock dump valves,  just swap them over.

[rx7-mark]

I am going to try and put it on the primary instead of the secondary and see if that gives me a proper dump but im still left with a vac hose left off.
I have no idea where to put it. I have tried t\'ing it in but that didnt work so im going to have to think about that one.

[antnicuk]

when you say you have a vac hose left off,  do you mean that you have a spare with no where to plug it?,  if so, just block it with a bolt.  if you dont mean that i\'m confused.

[rx7-mark]

Right its all sorted out.

The pipe that was left off was the vac to the charge relief valve,
The company i bought it off had taken the charge relief valve off instead of the standard dump valve so i had to repipe the induction kit so the dump valve was on the primary turbo instead of the secondary and the relief valve back onto the secondary.

To put it simple they had piped it up the opposite way to what it should have been and done a bad job at it too.

Thanks for all your help guys and i now have a lovely sounding dump valve that works.

It took some but i got there in the end.

with a induction kit and bailey u shd be getting a noticeable sound definatly..there must be another reason for not getting the noise..u say on idle it is reading -20.this is a very low reading..i dont thing negative pressure is measured in psi..my defi reads -5 to -6 on idle.i think u have a pipe off somewhere

I phoned jimmy\'s and dragon this morning and they said that running at -20 on idle is fine so im glad about that cos i thought i had another problem when it stopped at that after sorting everything out.

Thanks again guys.