Nah, this has Vova written all over it.Originally Posted by Evilchap
Maddog isn't back is he?
Nah, this has Vova written all over it.Maddog isn't back is he?
ach look I wanted a proper discussion or explanation of why it has to do this, not a fooking flaming to death for asking the question.
Know what? Stick your fookin SXOC up your arses!
I dont know who maddog or vova is or are, but if they were sane, no wonder they left. See ya
You can all enjoy yer little closed off world now
Last edited by EvilScotsman; 03-01-2010 at 22:28.
ok... admittedly i dont know the physics....
but... please believe me when i say it over fuels with a dv to atmosphere... and i am speaking from experience here...
im not disbelieving you mate. I am saying it doesnt have to do this, and why does it do it, thats all.
Its like going back to the Dark Ages here, when you werent allowed to question anything.
Cheers for the open minded attitude lads)
OK let me have a stab at this one...
How about.. the difference between using a Recirc and an Atmos valve is at the moment of closing the throttle the intake charge is vented. This causes a vacuum in the intake path. Now THIS would cause a rich burn even if the ECU is only expecting an Idle oxygen amount.That I can understand.
As far as just not running a DV at all I'm not so sure. Sure the compressed air is going to be forced back through the turbo etc but surely it would only drop to atmospheric pressure.
Its enough of a delay to make the car overfuel.
yes FOR A SPLIT SECOND!
And Dan, the pressure in a recirc pipe is zero. Neither vac nor boost, just zero.
What is going out, is coming back in, at the same speed less friction losses from the coanda (skin) effect on the pipe walls. At high flow rates turbulence is introduced, and has a Reynold's Number to describe the level of turbulence. Laminar Pipe Flow was one of my hard won subjects at university. I design pumps for a very good living, but according to all the others here, I am apparently a misguided soul. 30 years in pump and flow engineering wasted!
I should have known. And NO ONE put up numbers to prove THEIR point
Last edited by EvilScotsman; 03-01-2010 at 22:42.
seriously its been explained, ill read your thread ''why is my car overfueling'' soon
what is it you said earlier put up or shut up? Maybe you should as the more times people explain it in basically the exact same way you dismiss it. I have a vta my car overfuels didnt before and my dyno print off and every member who attended that day can also back up that it was overfueling and even the dyno operator said it was down to my dump valve but were all wrong
If your car is overfueling when its been tested on a dyno, ie under power/load then you've fitted it wrong.
under load and overrun massively overfueling
under load due to being on stock ecu and overrun because of vta and stock ecu
My car isnt overfuelling!!!
It is bone stock! I was asking an engineering question of the knowledgeable turbo guys.
What did you think I asked it for? There is nothing wrong with my car, it is factory standard. It was just a question.
I'm sure the injectors are cut on overrun/engine breaking?
Anyway, I dont think I'll bother asking anything else in the Closed Society of SXOC. You lot want to kill anyone who poses a difficult question that you really cant answer, except to give blind replies of info you believe to be true, I am not disputing it overfuels, just saying it doesnt have to - IS THAT CLEAR ENOUGH?
Anyway, goodnight Gentlemen, and I use that term loosely.
Keep it chilled mateAnyway, I dont think I'll bother asking anything else in the Closed Society of SXOC. You lot want to kill anyone who poses a difficult question that you really cant answer, except to give blind replies of info you believe to be true, I am not disputing it overfuels, just saying it doesnt have to - IS THAT CLEAR ENOUGH?
Anyway, goodnight Gentlemen, and I use that term loosely.
Dan, all injected systems since Bosch K-Jet cut fuel on the overrun.
If nissan dont, well that explains a lot of things. BMW have been doing that since the 80's.
I thought the Audi lot were anal! Jesus, you would think I insulted someones mother the way some folk tore into me for asking a question they COULDNT answer with any kind of engineering, science, maths or physics.
And in case anyone would like to know, I was a Toyota manufacturing engineer for 7 years, so I think I speak from a point of strength, but others seem to know best. Why do a lot of Jap tuners run no DV or VTA? Because it does no harm whatsoever.
Kabushiki-gaisha - or Toyota, in Toyota City, Aichi was my employer from 1992 to 1999 during which I oversaw comfort electronics and ICE manufacturing, before moving to Intel in The Republic of Ireland, then to turbine design at the Michelin plant for the 2 wind power units that stand on the coast of Dundee.
But I dont know what im talking about, so I officially lose interest in the onslaught that followed a perfectly good question.
Last edited by EvilScotsman; 03-01-2010 at 23:01.
Nissan do mate
The nissan ECU cuts fuel on overrun.
Sorry for the caps, just to distinguish your words from mine if your not trolling then sorry
Its odd then that itrhondaboy has a car that overfuels at a time when the injectors are not firing? Maybe they are stuck open?
Just because you don't want to understand the working of something doesn't mean you should put other people off trying to find out for themselves.
Sure I'm being anal about the overrun situation but it just goes to show the amount of crap that can get spread around the internet.
I've never once said they don't overfuel. I think we have reached a semi sensible answer with this one now though. Although the overfueling on lift off really is for such a short duration that I really wouldn't worry about it.
A little fuel goes a long way with regards pops/bangs etc. I think its generally only made worse by the fact that the standard map is rich at the top end anyway.
You don't need maths or physics to explain it.
If metered air isn't consumed by the engine then it will overfuel.
Ignore the whole turbo and dump valve thing for a moment and consider an N/A engine with an AFM. If you suddenly introduce a leak between the AFM and the throttle body it won't run right, it will overfuel.
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