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The mkiv Supra Owners Club

1.6+ bar on stock turbos


Homer

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Is it likely to cause problems momentarily hitting 1.6+ bar on the stock turbos?

 

Today I forgot I hadn't set up the bleed valve and took it for a run... after booting it in 2nd I thought 'holy f**k this is too quick' so let off the gas and remembered the bleed valve... The boost gauge recall showed just over 1.6 bar (plus my gauge reads low).

 

Did a couple of short blips on boost, I simply cannot believe how quickly it spools up like this, even at 4k rpm it goes from 0 to 1.5 bar is a fraction of a second! Just a shame the turbo's can't last like this!

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Lol...Throttle happy are we huh? Boost like that for a split moment isnt too bad, if the peak boost period was long enough your FCD would have come into play.

 

Are you still under boosting? (without MBC)

 

I know it'll hit huge boost without the FCD kicking in, but am concerned if a large, short burst has any immediate effect on the turbo or engine (det). It popped and banged a sh*t load after lifting off, something it doesn't normally do.

 

I've fitted a bleed valve so the days of underboosting are over. Hope to set it up tomorrow and be ready for some 1.2-1.3 bar runs at Pod on Sunday if the weathers good.

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Way out of the efficiency map, no point, unless you dont like your current turbos and you want to replace them very soon.;)

 

1.2-1.3 bar?

 

I know 1.6 (or above 1.2 aparently) is pointless on stock turbos but am concerned what effects this could have had on then engine or turbo...

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1.2-1.3 bar?

 

I know 1.6 (or above 1.2 aparently) is pointless on stock turbos but am concerned what effects this could have had on then engine or turbo...

 

Long burst over 1.3 bar would most likely result in the engine running very lean and det occuring, melting pistons, and all this before the tubbies would even die!

 

But with the mods (New I/C, pump etc) you have in place Darryl running 1.2-1.3 Bar would most likely worst case scenario result in early turbo failure if anything, and no damage to the engine as long as you can keep an eye on the AFR's and EGT'S.

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Thats the same conclusions I had drawn. With the spool up being so fast the AEM AFR gauge can't react quick enough, so I have no idea if it ran lean (it's normally incredibly rich at 1 bar throughout the range).

 

Guess only time will tell :) (32k miles BPU and still going strong - lets up the stakes!)

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Thats the same conclusions I had drawn. With the spool up being so fast the AEM AFR gauge can't react quick enough, so I have no idea if it ran lean (it's normally incredibly rich at 1 bar throughout the range).

 

Guess only time will tell :) (32k miles BPU and still going strong - lets up the stakes!)

 

Darryl, if you want my opinion then wait till you have an EBC (you'll need one when your single anyway) and then up the boost, this way the boost spikes will be more controllable (especially with winter comming up) as MBC's are prone for serious boost spiking with higher loads.

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At 1.6 with a normal JSpec you don't get a whole lot more air than with 1.3, so fuel-wise you're not that off.

It's the extra *heat* that could do damage, but if you are doing high speeds it takes a few seconds for it to build up in the chambers - it's not momentary.

 

You really risk popping-off the ceramic turbines though, and potentially scoring the turbo shafts and thrust bearings as well (also depends on how good/fresh your oil was at the time)

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