Air /Fuel Ratio Table.
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Air /Fuel Ratio Table.
Hope this helps a few of you out on working out you air fuel ratios,
Regards Tony C (COOPS)
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Procharger D1SC supercharger and Cossie RS500 Intercooler @ 14psi of Boost. 416 RWHP, (boost leak)
Forged 4.8 V8 kitted out with the dogs Cajones of parts.
Sponsored by: www.v8performanceparts.co.uk, www.interpart.biz, www.caprisport.com & www.baileyperformance.co.uk
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Procharger D1SC supercharger and Cossie RS500 Intercooler @ 14psi of Boost. 416 RWHP, (boost leak)
Forged 4.8 V8 kitted out with the dogs Cajones of parts.
Sponsored by: www.v8performanceparts.co.uk, www.interpart.biz, www.caprisport.com & www.baileyperformance.co.uk
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Looks as good starting point - and as you note, you will probably find it wants it richer than 14.7 around idle.adamnreeves wrote:I've been scouring the net for AFR targets for my 4.6 RV8. Found a few but this is the best I've seen. Comments?
the only adjustment I've made is at 45kpa-50kpa/ 500-800 richer to 13.5AFR as the RV8 likes to be rich at idle. My closed loop is only engaged above 1100rpm anyway.
Probably dont need as much as 12.5 on a n/a engine though - but 12.5 is on the safe side, so you wont go far wrong.
My lump and Muscle Manta's are both stage III 4.6's running Eddy 500 carbs and similar 285 cams. Both need the AFR around 12.2:1 in order to get a good idle. MM's idle was a fraction leaner than mine but not much. I think the long exhaust pipes that he has causes a bit more back pressure and that it good for getting a stable idle, I run large primaries going into sidepipes. I've watched the idle on my car go unstable just by turning the pilot screws in 1/4 of a turn, the AFR was around 13:1. My mates 3.5 with a mild cam will run leaner at idle. (I can't remember the figure).
Both the 4.6 lumps will cruise at 14.5:1, the setup was an 86 primary jet and a 69 needle. We then tried a 70 needle in MM's car and the cruise went down the pan showing 15:1, the car was not drivable! This was just a 1 thou increase in the rod size! The 69 rods are home made. The power step at the moment is 52 but we might try 55. With EFI I'm sure that leaner cruise figures can be used successfully.
Both the 4.6 lumps run 12:1 during 1/2 throttle acceleration (The 55 step might get this up to around 12.5:1). The WOT is 12.5-12.8:1. I have to run a 77 secondary jet, MM's runs an 83 secondary!!
Both the 4.6 lumps will cruise at 14.5:1, the setup was an 86 primary jet and a 69 needle. We then tried a 70 needle in MM's car and the cruise went down the pan showing 15:1, the car was not drivable! This was just a 1 thou increase in the rod size! The 69 rods are home made. The power step at the moment is 52 but we might try 55. With EFI I'm sure that leaner cruise figures can be used successfully.
Both the 4.6 lumps run 12:1 during 1/2 throttle acceleration (The 55 step might get this up to around 12.5:1). The WOT is 12.5-12.8:1. I have to run a 77 secondary jet, MM's runs an 83 secondary!!
Last edited by sidecar on Wed Jul 24, 2013 3:40 pm, edited 1 time in total.
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The factory setting for the 3.5 EFI is 1.5-2% CO, and I find I get a good reliable idle at 14.1 and 600 RPM. On a bog standard 3.5 with MS 2 V3 and IDIS.Eliot wrote:As a note, the 12.5 comment was in the wide open throttle area not the idle area.
Idle will need whatever it needs - it would be as rich as 12, but you risk plug fowling when its cold - try to get into the 13's
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
DaveEFI wrote:The factory setting for the 3.5 EFI is 1.5-2% CO, and I find I get a good reliable idle at 14.1 and 600 RPM. On a bog standard 3.5 with MS 2 V3 and IDIS.Eliot wrote:As a note, the 12.5 comment was in the wide open throttle area not the idle area.
Idle will need whatever it needs - it would be as rich as 12, but you risk plug fowling when its cold - try to get into the 13's
I think that you have hit the nail on the head, a bog stock engine will run leaner on tickover than one that has large bore primaries, gas flowed heads and a longer duration cam. On top of that EFI must help too.
Yup. Once you modify an engine in any way, the stock settings for ignition and fuelling go out the window.sidecar wrote:DaveEFI wrote:The factory setting for the 3.5 EFI is 1.5-2% CO, and I find I get a good reliable idle at 14.1 and 600 RPM. On a bog standard 3.5 with MS 2 V3 and IDIS.Eliot wrote:As a note, the 12.5 comment was in the wide open throttle area not the idle area.
Idle will need whatever it needs - it would be as rich as 12, but you risk plug fowling when its cold - try to get into the 13's
I think that you have hit the nail on the head, a bog stock engine will run leaner on tickover than one that has large bore primaries, gas flowed heads and a longer duration cam. On top of that EFI must help too.
When I was running the standard flapper injection on my 3.5, I bought a 'better' cam said to be suitable for the standard EFI system. Never got it to run properly, as there are no adjustments to the fuelling on that system, other than for idle.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
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im using it on my road car, a rover sd1. if you go to the post on pre-cut lexan the company web site is there and they do all makes of cars. Smile rich
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