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Discussion Starter · #1 ·
I snapped the little pipe off the top off my air box today - Doh!

So I thought it time to fit the Boost Controller that has been in my boost for months. So I fit the controller and gentally drive it down to a quiet private road. Then I run it to 2000 rpm in both 1st and 2nd then opened her up in 3rd. Oooppsss hit 16psi so took my foot off the go pedal straight away. Reduce the level quite a bit then try a run again. Get 9psi. Good, so increase it and increase it and increase it. Almost at the same level as before but only getting 9psi. Puzzling until I find the turbo has sucked in the air pipe from the air box. Anyway I reattach the pipe as it should be and start runs again, Hit 16psi so came straight off the accelerator and turned it right down. Managed to get it to 10-11psi before it got to dark.

Anyway I thought there was a boost cut in at 14psi, so how was I able to reach 16psi. I have the same boost guage as many of you here but now doubting how accurate it is. Could it be that I would have to be over 14psi for a certain period of time before the boost cutout kicks in? Any easy way I can test the accuracy of my boost guage?

Thanks :)
 

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i would say its the innacurracy of your gauge.

boost cut is 14.7 ( so nearer 15 psi ) so hitting 16 is quite possible.

how were you checking the boost level?

its quite important you do this in 4th or 5th gear.

i had my boost sitting at 14psi for ages and wwhen i got her dyno'd it came out at 12.5 psi so quite a big difference!!

double check the boost gauge pipes to be air-tight.

trust me, when you hit boost cut, you'll know it!! lol
 

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Discussion Starter · #3 ·
i would say its the innacurracy of your gauge.

boost cut is 14.7 ( so nearer 15 psi ) so hitting 16 is quite possible.

how were you checking the boost level?

its quite important you do this in 4th or 5th gear.

i had my boost sitting at 14psi for ages and wwhen i got her dyno'd it came out at 12.5 psi so quite a big difference!!

double check the boost gauge pipes to be air-tight.

trust me, when you hit boost cut, you'll know it!! lol
I checked all the pipes were air tight but was doing tests in 3rd. (Road I was on wasn't big enough for 4th).

I have heard about the boost cut out, the reason why I came straight off the accelerator when I thought I was going to hit it.

Would making the pipe to the boost guage as short as possible make the reading more accurate?
 

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Discussion Starter · #4 ·
hhmmm your right, you do know when you hit the boost cut lol.

finally able to adjust it to an indicated 13psi. Is this a safe level?

Thanks :)
 

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what is that little pipe on the airbox?

i snapped mine off the otherday,

so i left the pipe that was connected to do just dangling around, until i get it fixed.

i thought that it was just some sort of air temp thingy?

willl this effect perforamnce if its not connected?
 

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what is that little pipe on the airbox?

i snapped mine off the otherday,

so i left the pipe that was connected to do just dangling around, until i get it fixed.

i thought that it was just some sort of air temp thingy?

willl this effect perforamnce if its not connected?
you running a standard BMV or manual boost controller there, with a manual one you get rid of the pipe, i beleve it just release the extra boost from the BMV when it modulating it, should not make any diff at all
 

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willl this effect perforamnce if its not connected?
You should block it off on the airbox (use a screw or bolt), as that goes into the filtered side of the airbox. This means you are sucking some unfiltered air into your turbo - and it only takes a small bit of grit to damage the blades in your turbo, and an even smaller bit to damage your cylinders.
 

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yeah mate.

don't forget, it sounds like it over reading anyway.

so it probably is 11.5 - 12 psi?

only way to sort it for sure is either an AVC-R or get it dyno'd and it will tell you exactly and you guess from there.......

check you actuator arm has no play too
 

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Discussion Starter · #14 ·
yeah mate.

don't forget, it sounds like it over reading anyway.

so it probably is 11.5 - 12 psi?

only way to sort it for sure is either an AVC-R or get it dyno'd and it will tell you exactly and you guess from there.......

check you actuator arm has no play too
Actuator arm has no play, would love a AVC-R but my wife would kill me if I bought one.

When using the BMV I was getting an indicated 9psi on the gauge, assumed this was accurate as I believe the boost is set at 9psi when the BMV packs up?

Pulling better then it was before anyway so even if its at 11.5-12psi its an improvement on before.
 

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Actuator pressure can be anything from 6 to 9psi depending on how much preload there is in the actuator. I'd personally not run mine at 13psi on standard pistons, but it is luck of the draw whether it'll be fine for years and years, or whether it'll start smoking next week.
 

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this is an age old debate.

i say run it at 13 psi. mine was fine ( and i can proove it!! )

boost preassures are only a problem on long levels of boost i.e. a 2 mile straight with foot to the floor.

as most of us don't drive on full boost for more than a few seconds, i doubt it will kill it quick.

unless someone has owned the car from new, there is absolutly no way you can tell the life history of that engine to proove what you're doing is the problem

keep an eye on oil levels and coolant.

run 97 ron fuel and you should be fine.

its just 1 psi above stock!!
 

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It depends on what sort of pistons you have as to whether it is prolonged boost or just any duration of boost that causes the damage.

There are two types of piston. One melts and this usually happens through prolonged high boost as said above. The other type breaks the ringlands (the small islands of piston between the piston rings). This can happen at any time with a high boost level and the damage can take many weeks before it is notices (usually it starts to blue smoke). 11.5psi is stock boost so is generally regarded as as safe as you can get. Some people have got away with 14psi+ for ages whilst others have had problems running 13, so it is a case of luck of the draw I think. The size of turbo and intercooler also have an effect too. You can get away with a slightly higher pressure if you are running a bigger intercooler and/or a bigger turbo as the intake charge is cooler and so the pistons run cooler too.

The debate has raged for ages and ages, with no definitive answer so it is entirely up to you. I'm airing on the side of caution until I fit the new pistons and turbo and then 20psi here we come :D
 
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