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The mkiv Supra Owners Club

boost control!!


toyo rob

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right then,

 

i have a boost gauge and bleed valve, do i need a boost controller as well??.

 

prob is i was told i should run the 1.2 bar but i seem to run 1.2 in 1st and 2nd, then 1.3 or so in 3rd, then she flies up to 1.4-5 in the next 3 gears. soon to get a full de-cat done and since ive been having a few probs wih the exhaust at the mo, too many unfortunate problems to list just leave it at im feeling really unlucky, will she quieten down once a full system is in place. have had friends ignore good advice about boost and heard the stories so am really concerned. itts just so hard to not just put my foot down but have to keep an eye on the gauge to stop the OB.

 

plllleeeeaaaaassssseeee help,

 

Cheers

 

Rob S

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Though not an expert on such matters ...

 

A full-decat negates the need for a bleed valve or a boost controller.

 

You'd only want a bc if you were running with 1 cat still in the system.

 

I thought the safest maximum you can run at is 1.2Bar (18psi).

If it was my car - I'd take the bleed valve out and return it to 0.8Bar - until you get a decat done.

 

I'm curious however, that you managed to boost over 1Bar without a Fuel Cut Defender - unless you've already got one or your ECU has been remapped.

 

Clarkey

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EDITTED :)

 

Rob, check the bleed valve and the piping where it is T-d in. I set it to 1.2 bar in[ EDIT] COLD weather, so if its going higher (and you haven't adjusted it) there is a leak in the piping. Should be easy to find, where the valve is connected.

 

Also, if you are goin for a full decat, this will raise the boost on its own, so I would definately remove the bleed valve completely (Just replace with a piece of vacuum tubing). You may well need a 'restrictor ring', a small ring of metal which goes in the exhaust to bring the boost down to 1.2 bar (or lower!) after a decat.

 

Please dont run it too often at 1.4, she wont like it !

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BTW Sorry to hear that you are having problems with her. :confused:

The only thing I had, was an intermittently random active spoiler.

From reading on here, I think it was most likely the odomoter that may have been the cause. The odo resends the vehicle speed signal around the car, hence the confused spoiler.

As it was only occasionally and I planned to get a front mount IC (which means the active spoiler cant be used), I never worried about it too much.

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Got an FCD cause was runnin 1.2 beore all this started.

when i got the money obviously want to upgrade the whole doing a bit at a time when funds become available so eventually probably want to upgrade the engine and maybe push up the boost. does this mean cough up for a decent controller now and be secure in the fact that its not money wasted or what???

 

 

Cheers for the info, keep it comin,

 

 

Rob S

 

shes Jap, soon to be De Cat

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Its very unlikely that you will need a boost controller when you go full decat in a jspec. If anything a restrictor ring might be needed to bring it down to 1.2 bar.

 

By the way, you know that used to be my car right ? :) I think you bought it off me around April ?

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What I would do is set it to hit 1.2 bar in 6th in COLD weather. This way you have the worse case scenario, and so then in warmer weather (less dense air) and in lower gears you should only ever hit 1.2 bar max. (Running above this with your current set-up is not good, and could turn out to be costly!)

 

As has been mentioned, if de-cat is the way you would like to go, I would remove the bleed valve when you get that done, and fit a restrictor ring to bring the boost back down to 1.2 bar in 6th in cold weather.

 

When you start to make further mods, which will include uprating the fuel system and turbo's and then building the engine, you'd probably end up wanting something that will give you a bit more control over what boost you run, and end up buying an electronic boost controller. It soon add's up believe me......

 

Good luck with it ;)

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Oops yeah thats what I meant !

Sorry, it been a while. I set it to about 1.1 in the summer. And may have set it down a little for the winter.

 

 

Either way, the bleed valve was on there across all seasons, set to a max of 1.2 B, without needing adjusting :D

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IMHO a bleed valve is a nasty mod for a MKIV supra. It is very crude and will be subject to atmosphric changes.

 

You need a controller that will hold the maximum boost you set regardless of external conditions.

 

Use bleed valves and risk boost spikes at your peril.:flame Dev :flame Dev

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