How To do the Easy 1 Bar boost mod

[AJ4]

When I first got my car, it was running dead on 1 Bar. Couldn't find any boost controllers, didn't have an uprated actuator and I couldn't figure out how it was done. After removing the standard solenoid to fit an electronic boost controller, I found a small hole drilled in the side of the standard solenoid. Aparently its a common mod in Japan....

The car ran for over a year with this mod, exactly 1 bar boost, no spiking. I think the hole is 1.2mm, but if anyone wants to try it, I'd suggest drilling a smaller hole first and working up....

 

[Ash10]

This mod is really neat, for several reasons:

1. It's cheap...

2. It's hard to spot - for example, by a hypothetical insurance loss-assessor... :roll:

3. You can keep the correct operation of the solenoid...

For those of you who don't know, the boost control solenoid usually bleeds off around 0.2 bar from the wastegate actuator - the standard wastegate operates at around 0.5 bar, hence factory boost is given by 0.2 + 0.5 = 0.7 bar.

When the engine is cold or the det sensor has been triggered (possibly other operating conditions too), the solenoid closes and boost drops back to a "safe" 0.5 bar.

If you drill the hole on the "outlet" side* such that the solenoid now bleeds 0.5 bar, you'll get 1 bar boost - but still have the "safe" 0.5 bar setting if the engine cold/detting

*the inlet/outside side of the solenoid depends on how it's plumbed in. On my car, that photo shows the hole in the inlet side - in which case the hole would always bleed around 0.3 bar, regardless of the state of the solenoid. That would give 1 bar for normal operation, and 0.3 + 0.5 = 0.8 bar for "safe" mode :!:

Use common sense - look at your particular solenoid and see how it works, then work out the best place for the hole. Oh, and as Ross says above, start with a small hole and work upwards :idea:

 

[DOT2DOT]

Pikeys! lol :lol:

 

[gtir bean]

has anyone got a pic of how its meant to be plumed in?i had a look at one before and i think it had a t pice but cant remember if it was on the pipe from i/c to solenoid or actuator to solenoid.think it eas the i/c to solenoid one and went to the inlet pipe.im going to put mine like this tomorow i think.

 

[Ash10]

has anyone got a pic of how its meant to be plumed in?i had a look at one before and i think it had a t pice but cant remember if it was on the pipe from i/c to solenoid or actuator to solenoid.think it eas the i/c to solenoid one and went to the inlet pipe.im going to put mine like this tomorow i think.

(Big) plumbing diagram here - http://mummachummas.co.uk/pics/BoostControls.gif

 

[gtir bean]

so with everything plummed in the way it shows on the diagram where is the best place to put the hole?

 

[gtir bean]

i just put a 1mm hole in mine and it still boosts to .6 bar.that looks more like at least 1.6mm i think.

 

[gtir bean]

just put a 1.7mm hole in it and still boosts to .6 bar.the hole is in the same place as in the picture and i connected the solenoid upto the battery and i can hear it click.any ideas whats wrong?

 

[AJ4]

not sure, possibly your pipes are connected differently ? If I remember correctly ( and it was a few years ago ) the hole was next to the pipe that was going to the manifold / plenum, so it was bleeding off a bit of boost on the positive side.

 

[gtir bean]

i have mine plummed in the way it is in the diagram so the hole is on the side that goes to the actuator.i swapped them round the other way and it was at .5 bar.im sure its not in safe mode because the timing is ok.im not sure if the pipe i have coming from the back of the manifold has the restrictor in it or not if that would make any diferance.

 

[AJ4]

I suppose it doesn't make any difference if its fitted on the actuator side or not, apart from the safe mode issue.

Are you sure you have the restrictor pipe fitted ? If you can't get it to boost any higher then it sounds like you haven't If you don't have the restictor fitted I think it limits the car to actuator base setting, ie 0.5 - 0.6 bar.

 

[gtir bean]

ill check the pipe tomorow.it sits at bang on .6 bar at full chat.feels log slow compared to 1 bar

 

[Ash10]

How are you measuring boost? The standard factory gauge, or a proper/accurate one? :?:

If you bypass the solenoid altogether (ie: connect the input/output hoses together directly with a coupler) you should get more or less 1 bar. If you don't, then you might have a problem elsewhere...

 

[AJ4]

I take it you mean with the restrictor in place ? If you connect the two pipes together without it you'll have full manifold pressure on the actuator and will open at whatever its mechanical base rate is, around 0.5-0.6 bar. Not sure what it would be with the restrictor in place, like you said, probably about 1 bar. I suppose thats a good way to check if the restrictor is fitted or not, which is what you meant ? 8) Sorry, i was being a bit thick

If you disconnect the pipes altogether you'll get around 1.5 bar for about 4 seconds

 

[Ash10]

I take it you mean with the restrictor in place ? If you connect the two pipes together without it you'll have full manifold pressure on the actuator and will open at whatever its mechanical base rate is, around 0.5-0.6 bar. Not sure what it would be with the restrictor in place, like you said, probably about 1 bar. I suppose thats a good way to check if the restrictor is fitted or not, which is what you meant ? 8) Sorry, i was being a bit thick

You won't have full manifold pressure on the actuator, because some will be bled away into the main air intake - apparently this is the way Hiteq do a quick 1 bar mod, see here... http://bb.gtiroc.com/viewtopic.php?t=23789

As I understand it, the restrictor in the pipe between the plenum and the intercooler frame is to slow the rate at which the pressure builds up (to stop the actuator going prematurely) rather than limit the pressure itself.

It's also worth pointing out that the factory boost gauge is crap - I wasn't convinced by mine, so I disconnected the pressure feed to the sensor to test it. It read about -2 at atmospheric pressure (instead of 0) :? Full boost reads about +3.5 (instead of 5) which is about right for stock

If you disconnect the pipes altogether you'll get around 1.5 bar for about 4 seconds

Don't try this one at home, kids... :shock:

 

[gtir bean]

i have an hks guage.i was running 1 bar before but i just want it so the boost will be cut back if it starts to det or anything.

 

[alfyboy]

be carefull when doing this, cause i drilled the hole too big and the car is running at 1.2 bar :twisted:

 

[Fire & skill]

be carefull when doing this, cause i drilled the hole too big and the car is running at 1.2 bar :twisted:

i think you meant - i drilled the hole at the correct size and its 1.2 bar and not that pussyy 1 bar that the rest of you fucckers are running :lol:

 

[macphegf]

What is peoples opinion of this?
I'm wary of doing things cheeply like this but don't have the money to do it properly . If you do this does it mean that all you need is a fuel pump and air filter?

cheers

 

[Ash10]

I'm wary of doing things cheeply like this but don't have the money to do it properly .

If you don't have the money to do it properly, then you certainly won't have the money to fix it if you screw up... :shock: