Author Topic: Air Fuel Ratio??  (Read 6315 times)

Offline Prof

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Air Fuel Ratio??
« Reply #15 on: June 20, 2011, 02:17:44 PM »
Quote from: a.tapos;702220
I found a thread about this ages ago when i was experimenting and it appears alot of mappers especially americans prefer using lambda rather then afr though your probably better off sticking with what makes it easier for you lambda always confuses me because the measurement is the opposite to what im used to on a 0.1 to 1.0v narrowband sensor,though that in mind we dont use them to tune and ive only ever used narrowband readings on a standard car.Think i went off topic a bit oh well.

lambda and afr are functionally related lambda = afr / afr at stoich - so if you tune for one or the other the results would be the same - with one possible exception - and that\'s differing fuel types.  Since most people don\'t change the fuel type during running of the engine (I say most, because there are meth heads and people who have tanks of other stuff that get injected on boost), afr is fine - provided you tune for the fuel type.
 
Wiki says this :  http://en.wikipedia.org/wiki/Air-fuel_ratio
 
Petrol / Gasoline is 14.7 to 1 afr for stoich burn, but for a turbo\'d car you want to be a lot richer in the boost part of the map - high 11\'s seems to be the favoured numbers - but it can be dependant on whether you run WI or meth on boost, as this can allow leaner afr with no knock.
 
I\'ve been running close on 13.5 on warm idle, can\'t get it higher without the idle becoming unstable, and 14.7-15 in cruise - which is great for fuel economy :):)
 
I run about 11-11.5 on full boost which is too rich and the engine drops power, but it\'s staying that way till more mapping is done.  I\'d rather bog than have to rebuild. :cheers
"Plus this engine is probably one of the most volumetric engines going! It passes more air than a herd of cows eating vindaloo\'s" - courtesy of AtomicRex
 

FD Dave

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Air Fuel Ratio??
« Reply #16 on: June 21, 2011, 01:40:53 PM »
i dont plan to do any mapping myself, i just wanted to check my afr as when idlin i can taste the petrol in my mouth lol.

Offline woolley bully

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Air Fuel Ratio??
« Reply #17 on: February 25, 2013, 06:32:43 PM »
I know this post is a tad old now but can I adjust my fuel maps on my pfc 16bit without a datalogit just using the commander ? As in just adjust the fuel according to afr ? Cuz my cars über rich on tick over to the point where people\'s eyes start watering if I leave running to long :-/ lol

Offline Grant Monkhouse

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Air Fuel Ratio??
« Reply #18 on: February 25, 2013, 06:48:54 PM »
I\'m prety sure you can but your commander may have been locked out if you have had it mapped previously. Your going to need an AFR meter

Offline woolley bully

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Air Fuel Ratio??
« Reply #19 on: February 25, 2013, 07:17:31 PM »
Quote from: Grant Monkhouse;851721
I\'m prety sure you can but your commander may have been locked out if you have had it mapped previously. Your going to need an AFR meter


It\'s still on base map running twins parallel @7psi with decat system but runs very rich from what I can tell  ,, I\'m going to fit a single turbo set up the weekend , I\'m only looking to run 10ish psi as I\'m on stock fuel system , got afr meter on the way ,,but was wondering is the stock fuel system up to the task for running to4s @ 10pai ? an wanted to know if I could adjust the map until I get it mapped

Offline Grant Monkhouse

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Air Fuel Ratio??
« Reply #20 on: February 25, 2013, 07:24:40 PM »
I would say you are most definately goin to need either 850 primaries or 1680cc secondaries, and an Aeromotive fuel pressure regulator

Offline woolley bully

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Air Fuel Ratio??
« Reply #21 on: February 25, 2013, 07:48:40 PM »
Quote from: Grant Monkhouse;851727
I would say you are most definately goin to need either 850 primaries or 1680cc secondaries, and an Aeromotive fuel pressure regulator


In that case then I will mod the primary rail to take the 850 secondary\'s an just get a new secondary rail an run 1680s then with upgrade fpr , someone told me the standard fpr is 3 bar ? Any truth in that ? An also will the fuel lines cope with more than standard fuel pressure ? (Sorry if all this has been coverd before)

Offline Grant Monkhouse

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Air Fuel Ratio??
« Reply #22 on: February 25, 2013, 07:59:16 PM »
Fuel lines will be fine. Just keep the 550 primaries and get the 1680 secondaries with rail, and you defo need the FPR.

Offline woolley bully

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« Reply #23 on: February 25, 2013, 08:04:22 PM »
Ok will do ,, that\'s cleared that up ,, had loads of people saying that 10psi on a to4 would be fine on stock setup because the twins run 10psi standard

Offline Grant Monkhouse

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Air Fuel Ratio??
« Reply #24 on: February 25, 2013, 08:11:52 PM »
You are going to need to change settings on the ecu too, the injector sizes will need changing to 1680.

I suppose you could run it at 10psi without changing anything, providing you monitor the AFR gauge, BUT you won\'t be happy at 10psi for very long. On a single turbo 1 bar should be minimum.

If you have the cash to do the fuel system now then do it.

Offline woolley bully

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« Reply #25 on: February 25, 2013, 08:21:26 PM »
Hmmmm might have a re think on what I\'m going to do as I\'m planing to pull the engine out this summer so I think I\'m going to buy all the parts an fit everything in one hit wile the engines out ,, was hoping to put the single on an run low boost until I upgrade the rest of the parts but if there\'s a good chance it\'s going to run lean I will leave it until summer when I pull the engine an just stick with the twins for now

Offline Grant Monkhouse

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Air Fuel Ratio??
« Reply #26 on: February 25, 2013, 08:26:10 PM »
Best bet is to ring up one of the specialists. And ask your questions.

I personally would do the fuel upgrade before turbo or at the same time.

Offline woolley bully

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« Reply #27 on: February 25, 2013, 09:11:53 PM »
Ok mate , cheers for the info

Offline BlitzBoy

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Air Fuel Ratio??
« Reply #28 on: February 26, 2013, 11:39:33 AM »
10 psi on a T04S and 10 psi on twins is different, the TO4S will be pusing more VOLUME of air, it will be very lean on the stock base map of the APexi
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