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The mkiv Supra Owners Club

Bleeding T !


lovatt

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i fitted a 1/4" bleeder T to my 93tt jspec auto, i hit boost cut a couple of times last week but today i fitted the FCD, i dont get boost cut now but when the second trurbo cuts in it seems to judder, the boost gauge is flickering around 1.2 bar but at one point it shot up to 1.5 ! do i need to reset the ecu, can you feel boost spikes ?

 

the judder is like the boost is going up and down in cycles of 1-2 second intervals, but the boost gauge looks quite stable, it feels like when you are running out of petrol but there is a full tank of optimax.

 

i also noticed there is a small amount of oil comming out of the bleeder T, is this normal ?

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Hi Lovatt,

What type of bleeder is it? Have you a way of adjusting boost with it?

 

I ran a bleeder- for more than 18months without any problems. Mine was a metal piece with a screw-pin. I configured it on several runs by bleeding off the air bit by bit (by turning the screw), until I got a consistent 1.2bar (indicated on the boost guage). On very cold day it peaked to 1.3bar (indicated). My guage warning was set to just over 1.3bar. Only thing was that the adjustments were done under-bonnet, but a pipe can be fed from the open end to the cockpit.

 

Rgds,

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I got my bleeder valve from Chris Wilson.

Its very high quality.

 

It works very well and even I managed to fit it myselsf. If you have an extra piece of hose then you dont have to cut the stock hoses and its easier to put it back to normal if you need to.

 

Cuba

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This sounds very much like a spark plug problem, the plugs spark is being blown out by the higher charge pressure.

 

Have you got a cooler grade plug fitted than standard? If not you need to.

Try NGK 6097 (BKR7E)

(or the BKR7EVX as I've just fitted this morning)

 

 

So many people have the same problem and it's always been plugs.

 

You MUST fit lower temerature plugs when increasing boost. Bosch recommend a grade lower for each 15BHP increase.

 

If you see no engine warning lights it is NOT fuel cut.

 

I bet you'll find your problem feels very similar to hitting the rev limiter.

 

 

Regards

Pete

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Definitely not suggesting bleeders are being criticised and yes overboost can occur, but it is important to clarify that that really does depend on the type of bleeder used i.e. the mechanism used to adjust the amount of air being bled off. If the mechanism is not robust, then air can leak around it, thus leading to overboosting. The screw-pin type bleeders (circa £10) perform the function very well indeed and as I say, slight variations were experienced (dependent on many factors) but never overboosting.

 

Rgds,

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i am running the 1/4" T without any sort of valve, i thought it was just optional. have i got it all wrong as usual ! even though it seems to hold 1.2 bar ? it only went to 1.5 once and it wont seem to do it again

 

i had thought of the spark plugs and yes it does feel like the rev limiter, i will get the recomended plugs tommorow as i dont know how long mine have been on the car anyway (only had it since december)

 

thanks for all the help, anymore is welcome

:)

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If I read that correctly then there is no way you can control your boost. Some days it might be 1.2bar some days it might hit 1.4bar. You are at the mercy of your wastegate. My advice for what it's worth would be to either fit a valve to your current one, get one off CW (will have a valve/screw-pin to control boost), or go back to stock and raise boost with an electronic boost controller.

 

Rgds,

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Well I certainly didn't need mine once my car was decatted! I know of a couple UK spec owners who retained the bleeder after decatting, but as yours is a J-spec, you shouldn't need it anymore. Which incidentally, is a good reason for not butchering the original pipework.

 

Rgds,

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Great stuff. How is the 'calibration' going? As for the #1 turbo bleeder mod, I've not been tempted to try it but I recall that a chap (Hardhead?) might have done. Or maybe his experiment was the 'true-twin/parallel turbo' mod. I can't remember for sure. Your best bet is to do a search.

 

Rgds

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