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running lean


costas1

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Do j spec supras have the same fuel pump as uk/us ones? And yes dynojet dynos seem to show slight bigger numbers than mustangs...but do not know if the afr sensor the tuner used also is a bit off..cause as i wrote above the car's setup is like this for at least 6 years..it should be something wrong by now i think

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I had a dyno run done years ago with a bunch of others when I had hybrids, 550cc injectors, a Walbro, and Chris Wilson had done the fuelling with an Apexi AFC. Their dyno was only rated to about 450bhp, which they didn't own up to, and instead they hung the wideband out the tailpipe to pick up ambient air and accused my car of running so dangerously lean they had to abort the run, and that'll be £40 please.

 

So maybe it's just dodgy dyno operators if you've been running like this for 5 years.

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They installed the afr sensor in the tailpipe also ..is that the wrong way to do it?i do not know..i guess the best thing i can do is to.take the car to another dyno..problem is there is anotherone available here but is also a dynojet..my question is this.,bpu mods are standard and i have all of them made except the fuel pump(according to some stock.pump is good.enough)..all bpu supras run between 1-1.2 bar boost.,do all of them run so lean like me?my.thought is either my injectors or pump need to be ckecked.or the dyno and the sensor we used is all over the place

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They installed the afr sensor in the tailpipe also ..is that the wrong way to do it?i do not know..i guess the best thing i can do is to.take the car to another dyno..problem is there is anotherone available here but is also a dynojet..my question is this.,bpu mods are standard and i have all of them made except the fuel pump(according to some stock.pump is good.enough)..all bpu supras run between 1-1.2 bar boost.,do all of them run so lean like me?my.thought is either my injectors or pump need to be ckecked.or the dyno and the sensor we used is all over the place

 

 

 

Going by all you have said I would suspect the dyno operator of not putting the AFR sensor far enough up the tail pipe, (it could be due to there being baffles in the way so it couldn't go further) anyway the result is that the is too much atmospheric air being read, giving rise to the weak mixture reading.

 

If you car has been running fine for so long I think its highly unlikely that its a genuine reading, it would have caused damage long ago,

If you are concerned I would either try another wide-band sensor/dyno, or buy yourself a decent wide-band set up and fit, that way you will be able to tell your AFRs at a glance.

Normally all BPU supras will show rich mixture at WOT IE around 10AFR.

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After a quick read:

1. EGT Sensor in the Decat is totally useless BUT if you are really seeing 800°C in there you're in a Temp range before the Turbos that is highly dangerous AND it would indicate that your AFRs are really on the Lean side. On the other side i don't think it will be into the 14s otherwise you'd have knocked out the engine Long time ago. And maybe you have but it's not showing yet. We've had 2JZ Engines running like a charm and when forging the engine 1 or more conrods were bent.

2. The Jspec Pumps are weaker and will go into the 12-13 AFR range on 1.2bar. The EU/UK are a whole other story.

3. No way in this or another dimension will you get 425 Wheel horse power on a JSpec with 440CC Injectors. Crank Horsepower is another story though. This would be achievable.

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@tricky first of all thx for all the replies and your concern..the egt is hks and maybe i am saying wrongly as where the sensor is located(it is approx in the middle of the car on the exhaust pipe)when you get your self on the ground you can see the sensor fitted on the exhaust.. as far as the dyno wideband in the video i posted at the end when the camera comes in the back you can clearly see the sesnor used stack in the muffler in the back..(do not know if this is how is supposed to be)

@tuneR broken gasket you mean head engine gasket? if i had that i would have engine temperature problems right? i don't..the car runs smooth

@cannislupus.thx for the reply as i wanted to know about j spec fuel pumps..so a wallbro 255 is better than a j spec crap?

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Although the EGT sensor is fitted in the wrong place (normally should be fitted to no 6 exhaust manifold runner before the turbo to get authentic readings)

I am still inclined to think its faulty, as 800C would mean manifold temps of over 1,000C which would indicate a big problem.

 

@Costas1 are you sure this is the EGT sensor? and not the std cat temp sensor?

 

As I said previously IF the wide band AFR sensor was not inserted far enough into the tail pipe, it will NOT show the correct reading.

As for the fuel pumps, its a case of different opinions, I have run my BPU supra with a std J spec pump and had genuine AFR readings of 10 AFR and under on my Innovate wide band AFR gauge, and later changed it for a walbro 255 and got exactly the same AFRs.

 

Anyway as I said the only real way to double check this is to fit a wide band AFR gauge and check for your self, as I strongly suspect that your tuners dyno is set up wrong.

 

Costas1 can you maybe post up some pics of the EGT sensor location?

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@tuner were you talking about an exhaust gasket?

 

Ya one of the 3" gaskets on the connection between the first and second decats had a break in it, taking in air but car was running fine, couldn't figure it out. Only found out when putting the cat back in for the NCT (Irish MOT).

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@tuneR thx.i will try and take the car to an exhaust garage to check the gaskets..i am planning to take the car to another dyno end of the month and see what happens..i have been searching in you tube and on the internet and i saw a lot of bpu supras (jspec and uk/us spec) hitting 400+ on the wheels so i do not know whats true or not..all i am saying if the second dyno shows similar numbers i will be very confused..we have to start the discussion all over again..lol

i do not know how much difference would make that here we use 98 octane gas and for my run we used some octane booster also..

 

 

p.s.. i was told that a uk bpu supra in greece hitted 500 on the wheels just with a remap..

Edited by costas1 (see edit history)
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yes i know ric..but an aftermarket ecu is still bpu right? this guy was talking about stock twins stock injectors and they hit that on 25psi of boost..anw as i mention above i saw a lot bpu supras in you tube hitting above 400 on the wheels so i do not know..i will test a second dyno end of the month

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As I said in my PM Costas, I have never seen a BPU supra achieve a genuine 400BHP at the wheels, and I am very doubtful its at all posible, I think 400- to 420BHP at the flywheel is possible using a piggyback ECU to lean out the over rich fuelling and adjust the timing also.

But as soon as you start to push the boost on the std turbos beyond their efficiency you will just end up with high EGTs and loose power.

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You cant remap a standard ECU. It will be a lot more than BPU, 500 is also a stretch, perhaps 430-450

 

The Standard ECU can be remapped. There even have been modded ECUs with map Switching. But as everyone was following the lazy ass americans piggy backs etc became the standard and the OEM ECU was deemed umappable... :(

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The Standard ECU can be remapped. There even have been modded ECUs with map Switching. But as everyone was following the lazy ass americans piggy backs etc became the standard and the OEM ECU was deemed umappable... :(

 

The standard ecu can't be remapped, hence why piggy backs and stand alone ecu's like Syvecs are so popular.

 

Not because of Americans.

You can get modified ecu's, but that's not remapping.

It's not plug and play, and has nothing to do with lazy americans.

 

It's down to cost, and what is achievable.

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