S5 turbo..


Not sure what that hardline tee hose goes to, had my mbc from the end of that to the wastegate.

What the heck is that hardline for? From what I know, its a Jspec TII motor. I've had my mbc ran like this for a while but I never noticed any change , figured I didnt have much time to fine tune so I ran it like that for a while.

Picked up a Halman mbc that I am switching in now and figure Id clean this up.

If its just another vacum source, cant I remove it all to clean it up and cap it off wherever the other side leads to?

 

it's for the S5 turbo pre-control solenoid. if you have an electronic boost controller then omit it and cap the line. if you have a manual boost controller you may be able to fine tune it with the solenoid still hooked up. it overshoots the boost at lower RPMs to get the turbo spooled up to max quicker.

the purpose of it is to dump excess boost pressure that the wastegate actuator would see to start opening the wastegate, it basically holds it shut a little bit longer.

 

would i benefit from removing it? i just did some initial test drives, boost may go up to .7 then down to .5

 

If you have an EBC or ball-and-spring type MBC, there's not much need for it. Either of those can keep the wastegate actuator from seeing boost pressure until the desired threshold. Doing so allows the quickest possible spool-up, which is what the turbo duty solenoid is there to do on S5s. Is it even hooked up to anything on your car? If not, the extra nipple isn't doing anything. I just have mine capped off on my S5 turbo, but I should have just unbolted the metal hardline when I was assembling the engine. It's bolted onto the compressor backing plate, so you'd have to remove the turbo to get access.

 

You can remove it, get a $15.00 manual (spring/ball) boost controller off ebay. The electronic one is not as reliable as the manual one.



Here is a picture of mine. It's just going from the nipple after compressor through the boost controller, and then on to the wastegate.

**note** Be careful when you first install a manual controller and you are adjusting it. You might hit the fuel cut if you exceed 10 psi. It feels like you literally hit something.

 

How much boost are you trying to run anyway?

 

hey i have an 88 series 4 vert..ive just installed a boost controller...how much boost can i run before the fuel cuts and...when the fuel cuts is it because the fule pump cant handle the load or is it the computer cutting off the fule so i will have to get a piggyback?
thanks

 

If this is a turbo model, fuel cut is at 8.6 psi. If you do not have an upgraded fuel system and fuel control, you should not be trying to exceed this level. The fuel pump drops in flow, and the secondary injectors stage too late for high boost in the mid-range.

 

ok..i only have the stock boost guage atm untill i install an upgraded aftermarket one..but im pretty sure im not running anywhere near 8. more like 5-6 and it still cuts off. so i need to upgrade my fuel pump or do i just have to get a fuel cut defencer? ive heard that s4 cuts at like 5.5psi or somthing small like that?

also.....if i just need to get a fuel cut defencer so i can raise it to abt 8 or 9 psi what is the limit where i will require a new fuel pump?
(im running with stock ecu and fuel pump atm)

 

lunchbox- I gained 30hp across the entire mid range when I went to a electronic boost controller, the manual one would start to bleed off before it reached full boost. Only reason I had the manual one in there is because the solenoid was not working on the used controller I had in the car at dyno time

For all out drag racing I can see it, for a street car no thanks

 

The fuel cut is saving your engine.