turbo boost discharge
Turbo Mini Forums

when my metro was running it seemed to have a problem when the turbo was spinning up.
in first and second gear the car would be fine, turbo would spin up nicely and go, and the dump valve would blow between gears.

but when in 3rd of 4th gear, when the turbo starts to spin and i put my foot down a bit more it seemed to dump all ov the pressure out and go nowhere. it would do this repeatedly.

can any one give me any possibilities.

i have also been having probs with the exhaust manifold keep leaking and blowing thru the gasket, this could be something to do with the boost discharge prob. i dont know.

i was told by sum 1 one this site that the manifold could be warped and that this does happen so i have been looking for a new one and attepted to remove the old one. The manual says i am to drop the whole exhaust from underneath which i really havnt got time to do. is this right? there is no easy way....

how much boost are you running dude? have you blocked off the standard overboost valve in the plenum if you're running over 10psi or so?

Other than that check all your boost hoses etc, all i can think of at the minute.

i'm sure this will be the std valve as bud says.

take the plenum off and split it in two. the valve and spring should be visible. then just either strengthen the spring (people do this with 5p's!) or block it off completely.

manifolds are known to warp, it needs to come off and be sorted. you dont need to drop the exhuast, just remove the clamp and leave it hanging there. its not a quick job to get it all off though really.

A new one could quite easily be warped as well, its better to use yours and sort it as once its heat cycled then its unlikely you'll have to do it again.

ps, the only reason you get it in 3 and 4 and not 1st and 2nd is most likely due to you not really seeing full boost till 3rd gear.

even with the standard over boost spring thing it would still dump out the dump valve in all gears.

could be the inlet pipe crushing when sucked.

could be the fuel filter starving it under load. (with a float chamber full it would run for a bit ie 1st and 2nd then run out in 3rd)(try coasting in 3rd and then boot it)

could be lots of things. where do you live? some one here could have a look.

Im from OXFORD keep meaning to put it by my name, if sum one could have a look that wud be great cos ive come to a point i dont know what to look for.

i havnt altered any thing so it should be running standard boost, which is 4-5psi??

i have blocked off the standard dump valve and put an aftermarket one on the plenum.

and thanks for more info on the manifold, ill unwillingly crack on with it later.
if any one can come and look at my car for me it would be much apreciated. PM me or sumthing.

they will blow round the metal gasket i have had probs with mine in the past you just have to do them up bloody tight and put the tabs over.

always looking for them bigger bunches of bannanas

still sound like the pipe from the air filter to the turbo sucking flat when on boost. seen it so many times. runs well but as it comes on boost there is a total loss of power. try it without the pipe but remember anything being sucked in hits the turbo thats spining at silly speeds causing massive damage. only run as a test.

as for the manifold. yes they do warp but it is important to fit either the turbo manifold gasket or the injection manifold gasket.

yeah i have been looking on mini sped and seen they do a reinforced gasket for injection and turbo's. im going to get one of them and just have one last go to see if it will blow. has allready desrtryed 3 standard gaskets. minispeed also sell the intake hose so i may aswell buy 1 of them too to elimanate the other prob. i will let u know how it goes....

sorry if got the wrong gasget, the injection ones ive found the best

always looking for them bigger bunches of bannanas

I have always found that std metro turbo items work best for me, providing the surfaces are flat and the ports do not excede the metal reinforced rings

a little update:

i have reassembled the top halef of the engine now.
i got a reinforced manifold gasket from minispeed and fitted that along the new manifold studs washers and nuts.

Fitted a new air inlet hose from the turbo to air filter as someone metioned above, the old one wasnt in the grestest condition which i really didnt notice the first time it was off.

when i originally took the carb off i did completely block off the std dump valve, left the end cap in there with a bolt behind it. (this is cool right)

SO ALL SEEMS WELL. it started a dream afterwards and after setting the tappets up it sounded sweet as a nut. MOT is booked for monday so im not really driving it before then in hope that the manifold gasket doesnt blow AGAIN. fingers crossed my baby will be on the road next week.

Keep at it buddy you will get there in the end.

hi people. the metro flew thru its MOT on monday without anything needing to be done. allthough it broke down on the way to the mot garage. LOL
it seems when the carb gets hot it doesnt like me and doesnt start.

i am still having the problem with turbo boost type discharge.
it seems like the wastegate/actuator is stuck open according to a friend of mine.

when i get it up to 3500/4000 revs the turbo starts spinning up when its about to kick in it bottles it and kind of stuters
IF ANY 1 is around oxford area maybee you cud come and see my problem and put your finger on it.

i have a spare actuator you can try

just a couple of things.

first, you said you blocked the standard dump valve. this is not a dump valve but a safety releif valve. this lifts at 7/8psi to stop over boost. i hope your bolt seals this, if not when on boost there will be a wistle from it. (could be your problem but not likely)

second. your loss of boost.

it could be the fuel pressure regulator. this could be plumbed incorrectly or out of adjustment or broken.

it could be a split pipe, the short one from the carb to the carb/inlet manifold. when this goes totaly the car will run but not pull away, you could have a slight leak.

it could be a boost leak. check the silicone hose from the turbo to the plenum etc. if you have a massive boost leak it will drive fine at low revs and off boost but will splutter like mad when it should be on boost. again could be the ally pipe from the turbo, the orange silicone hose, your bolt in the plenum.

infact the more i think about it the more this confuses me. how can you retain the plastic cap/seal in the safety valve and have a bolt fitted? i use a nut, bolt and washers through the hole with sealant. i cant see how the original cap can still be there. are you sure this is blocked and air tight?

if the waste gate sticks open you get no boost and the car drives like a 1ltr. if it sticks shut the car goes like stink with massive boost levels untill it blows up.

I had a similar problem with mine at Avon last year, it would boost in 1st and 2nd but nothing in 3rd and 4th!

It turned out to be an intercooler hose not sealing up properly on the intercooler and popping off when i got to full boost.

Check your hoses are all tight, and if your running an intercooler check that its not blowing anywhere. if there are no visable signs of leaks then it could be worth running without it to see if it makes a difference.

if that side seems ok, check that the hose from the plenum to the FPR is ok. if its split you'll be under fueling but only notice it when theres load on the engine e.g 3rd and 4th gear.

Where abouts Oxford do you live?

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1/4mile in 13.2sec @ 111 terminal on 15psi

Just thought are you still running that electronic boost control (cant think what the correct name for it is) Lol.

I may be wrong but that stages the boost 4psi to 7 or 8. if your bleeding air off that could be something to do with it?

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1/4mile in 13.2sec @ 111 terminal on 15psi

i am not running any type of electronic boost control (unless it is fitted as standard)

im from wallingford just outside oxford itself.

the metro came with an ECU to limit boost so as to save the gearbox.

i've just seen the photos you have posted of the white metro turbo. and seen the engine bay.

it looks like your running K&N crank case breathers. you also have the hose from the top middle of the inlet manifold to the one way valve and the intake pipe. since you have K&N filters there's no need for this pipe and the one way valve ( red colour plastic thing ). since these can go wrong leading to a boost leak you could check this