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Discussion Starter #1
hi ,

i just bought a boost gauge thats 2nd hand , it was fitted to a rover 620ti . he wired it up properly but the boost pipe looks dodgy, it goes from the gauge and half way the pipe changes to halfords clear washer pipe! and then it went on the back of the manifold, he said it sometimes went up to 20 psi!

is this right? i have not fitted one before so does that sound right? is it just one pipe that goes to the nipple on the back of the manifold ? no box or anything?

thanks
john
 

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mine has a single pipe that goes from the gauge all the way to the fanimold...teehee...mine never goes up that far! it just goes upto about 12psi and down to about -30. Which as far as i know is 'normal'. If he plumbed his boost modulator valve up wrong it may over boost like that, or if he has a manual boost controller and has set it 'high'.
 

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Washer pipe is ok, it will do the job fine. And yes, it just goes to a single nipple on the back of the inlet plenum.

If it goes up to 20, and the gauge is in PSI, then that's very bad news - it means the car is overboosting. However, the fuel should cut out at 14.7psi - this is called boost cut, and you'll know it when it happens, because it will just stop accelerating very suddenly, and you'll get thrown forward. If it is overboosting, then there are a number of possible causes, damaged actuator pipe, broken actuator, sticking wastegate etc.
 

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It could be that it was going DOWN to 20 rather than up to it which would be far more acceptable :D
Washer tube is fine, I've used it for years.
 

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Discussion Starter #5
thanks for the replies,

i fitted the boost gauge on my car today and mine seems to be boosting normal but i thought id check it with you lot first

it is at 9/10psi when the revs are at around 4k

and only gets to 12psi at around 5.5k revs or a little more even

i thought that it was supposed to be at 12psi from 4k?

thanks
john
 

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If the original boost control valve is working you'll get a max of 11.5psi
The boost will gradually increase from 6-7psi up to the regulated 11.5psi as the revs climb. You should be getting 6-7psi at around 2.5-3k rpm. Then it'll climb upto about 11.5 at 4-4.5k rpm.

Check that the wastegate isn't rattling. If it is it needs tightening up (easier said than done unless you have really small hands). They tend to go slack with age and you get a metallic rattle at idle and low boost figures if this happens.
 

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Discussion Starter #7
there is a rattling from around 2k - 2.5k but it goes after that and doesnt do it if u use the throttle very lightly,

how do i adjust the wastegate?
 

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If you have very small hands and patience you can do it with the turbo still fitted. Simply remove the actuator arm after loosening the locknut then wind a bit more pre-load into the actuator arm, (half a hole past the wastegate arm is a good guide), then refit it and retighten up the lock nut.
All the work is behind the turbo so access is rather errr interesting.
 

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Discussion Starter #9
just went for another spin and noticed that the car was strugling to get past 9 psi in first gear, in the other gears its a little bettter
 

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If the original boost control valve is working you'll get a max of 11.5psi
The boost will gradually increase from 6-7psi up to the regulated 11.5psi as the revs climb. You should be getting 6-7psi at around 2.5-3k rpm. Then it'll climb upto about 11.5 at 4-4.5k rpm.

Check that the wastegate isn't rattling. If it is it needs tightening up (easier said than done unless you have really small hands). They tend to go slack with age and you get a metallic rattle at idle and low boost figures if this happens.
There is deffo a problem with mine, it maxs out at about 8psi in 5 gear at 4k rpm then seams to die off :eyes: but then again my bar between the actuator and wastegate does rattle :lol:
 

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just went for another spin and noticed that the car was strugling to get past 9 psi in first gear, in the other gears its a little bettter
9psi in first! you will not get the full 11.5psi in 1st or 2nd i beleave, mine doesn't get past about 4-5psi in first , 5-6psi in second the about 8psi in third to fifth.
 

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Discussion Starter #12
also forgot to say that around 2-3k revs the boost seems fine its getting 6-8psi like it should. its after that which suggests it aint boosting properly as the boost doesnt change much
 

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get a boost controller on there and go for 12 psi through the whole rev range! dont boot it in first or second too hard though or it will be bye bye gearbox!
 

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It could just be a failing boost control valve. They aren't the most reliable of things. To check bypass the valve and just run a pipe from the bottom of the throttle body to the actuator.

The boost should now read a solid 6-8psi (actuator pressure) from 3k up to the red line.
If it doesn't then there are issues with the turbo rather than the boost control valve.
 

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Take measurements in 3rd or 4th gear too as in the lower gears things change too fast to see and monitor them properly.
 

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Discussion Starter #17
It could just be a failing boost control valve. They aren't the most reliable of things. To check bypass the valve and just run a pipe from the bottom of the throttle body to the actuator.

The boost should now read a solid 6-8psi (actuator pressure) from 3k up to the red line.
If it doesn't then there are issues with the turbo rather than the boost control valve.
ok ill look into that this weekend, tomorow morning im going to put my new KnN panel filter in and refit the airbox and boost hoses and check if they are leaking at all

if i dont find a leak ill do as you say, or get the wastegate tightened up - how much would it cost for this to be done by a tuning company?

thanks
john
 

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ok ill look into that this weekend, tomorow morning im going to put my new KnN panel filter in and refit the airbox and boost hoses and check if they are leaking at all

if i dont find a leak ill do as you say, or get the wastegate tightened up - how much would it cost for this to be done by a tuning company?

thanks
john

As i've been advised it's eather small hands, take turbo off or undo exhaust mainfold for more space so not that cheap for the last two
 
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