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The mkiv Supra Owners Club

Running lean on dyno


Slippery

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hybrids at 1.4bar should result in around 400BHP-420BHP at least, as the std 440cc injectors should be capable of supporting 420-440BHP at 100% DC,

 

 

This is a very good point! also running lean would give you a higher power figure mine run into 11.8 which gave me a massive power figure.

 

are you running ttc or sequential i know what the plot looks like but want to be sure

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Do you have an exhaust gas temp gauge fitted?

 

For now I would turn down the boost to 1.0-1.2bar - fueling *may* still be marginal at 1.2bar with the extra air flow the hyrbid turbos provide - I would err on the side of caution until you can get an AFR fitted and check what boost pressure is safe to run.

 

UK 550cc injectors are a straight swap but you will also need to fit a resistor pack as the UK injectors are low impedance (J-spec injectors are high impedance and do not need a resistor pack.)

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UK 550cc injectors are a straight swap but you will also need to fit a resistor pack as the UK injectors are low impedance (J-spec injectors are high impedance and do not need a resistor pack.)

 

Or get some Power Enterprise High Imp 550cc drop-ins :)

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Lowering boost to 1.2bar is a good idea its the 12v mod I dont like, depending which guide you follow it will leave the pump running all the time, even in the event of an accident which I wouldnt fancy if I was stuck in the car, hence my dangerous comment. Also the 12v mod only really has any affect off boost and low boost as the pump switches to full 12v when needed anyway.

 

Unless I am misunderstanding something here.

 

Its possible the fuel pump controller isnt switching to 12 volts under boost or dropping its output even when switched - hence lower fuel flow ,its not hard to wire for engine off /pump off . its only switched to quieten the pump and heat the fuel a bit less

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There is a couple of things in this that don't quite add up, firstly your run of only 379BHP with hybrid turbos and 1.4bar, i ran 369BHP on std turbos at 1.2 bar,

in theory and quite often in practice, hybrids at 1.4bar should result in around 400BHP-420BHP at least, as the std 440cc injectors should be capable of supporting 420-440BHP at 100% DC,

 

The second being that when the std ECU sees full boost or more, it will run the injectors by default at 100% DC,

Now providing the std fuel pump is in good condition it is also capable of supporting the fuel volume.

 

I also ran hybrids in TTC mode at 1.3 BAR useing EMU, and at first std 440cc injectors,and i was actually pulling fuel in order to get it out of the 9 and 10s AFR.

 

Ashleigh at Austec said that they were not running with air comparsators on the dyno and was getting wheel spin aswell . Otherwise it would of shown around the 410 mark.

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This is a very good point! also running lean would give you a higher power figure mine run into 11.8 which gave me a massive power figure.

 

are you running ttc or sequential i know what the plot looks like but want to be sure

 

I am running sequential

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Ashleigh at Austec said that they were not running with air comparsators on the dyno and was getting wheel spin aswell . Otherwise it would of shown around the 410 mark.

 

so how did other cars make more power then yours then, i dont know lets say 799bhp like steve m now im sure that would wheel spin

 

anyway thats not the point dont want to drag this off topic

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Its possible the fuel pump controller isnt switching to 12 volts under boost or dropping its output even when switched - hence lower fuel flow ,its not hard to wire for engine off /pump off . its only switched to quieten the pump and heat the fuel a bit less

 

 

Thats also a good point, and could well have that affect.

 

Ashleigh at Austec said that they were not running with air comparsators on the dyno and was getting wheel spin aswell . Otherwise it would of shown around the 410 mark.

 

The default AIT compensation on the dyno from not having it imputed or connected, shouldn't make a big difference, and also that chart shows not characteristic's of wheel spin, so i am confused.

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Lowering boost to 1.2bar is a good idea its the 12v mod I dont like, depending which guide you follow it will leave the pump running all the time, even in the event of an accident which I wouldnt fancy if I was stuck in the car, hence my dangerous comment. Also the 12v mod only really has any affect off boost and low boost as the pump switches to full 12v when needed anyway.

 

Unless I am misunderstanding something here.

 

Its only dangerous when bodged and not done with a relay, done properly the cut out will still work, its not even on a stock pump its on either a walboro or Bosch, both motorsport pumps designed I guess to work at 12v not 9.

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This is a very good point! also running lean would give you a higher power figure mine run into 11.8 which gave me a massive power figure.

 

are you running ttc or sequential i know what the plot looks like but want to be sure

 

I am running sequential

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so how did other cars make more power then yours then, i dont know lets say 799bhp like steve m now im sure that would wheel spin

 

anyway thats not the point dont want to drag this off topic

 

Don't know mate only can say what ashliegh told me .

Not out for willy waving of mines bigger just want to get her running safely.

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Stock MAP sensor is a consideration also - doesn't have the resolution to 'see' past ~ 1.1 bar, hence the ECU opens the taps on the injectors 100% at the voltage the FCD is set to clamp the signal at. FCD adjustment should be set to clamp at 4.3 volts IIRC (feeds stock ECU that signal at boost levels / voltages above that to stop the fuel cut safety) so whatever setting equates to this on your model FCD, lower clamp settings would mean the stock ECU is fuelling for lower boost levels and could give some more fuel if adjusted.

 

Please check my values above out - it's been a while since I messed around with this stuff.

 

Personally I'd just wind the boost back as it just gets super heated above 1.2 bar ish anyways and the power gain is severely diminished, best setup is stock ceramics before going single - hybrids are just plain shit IMO as the gains are minimal especially when you factor in the stuff to do it right as Wez has detailed and are at the expense of lag.... then they invariably self-destruct.

 

:)

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