ideal a/f ratio for b series

[lan evo]

wats the ideal af ratio for b series engine?

 

[hattech-v]

13 shud be ok

 

[hattech-v]

ops.. that one for WOT... cruising 14.7-15.5

 

[lan evo]

so running 12 to 11 on wot consider very very rich lo?

dyno my b16a the other day,only 134whp

afr 12 from 3krpm to 6.5krpm
afr 11 from 6.5krpm

 

[hattech-v]

quite rich.... :)

 

[J101]

as long it doesnt knock at this scorching heat malaysia weather its ok.

 

[udengfahlawi]

safer for it to be a little rich than lean....better to lose a bit power than lose the whole engine....

 

[chris2000]

safer for it to be a little rich than lean....better to lose a bit power than lose the whole engine....

Yup. but going too rich also kills the engine.

2 years ago my MME engine ran 13.5:1 part throttle and at peak rev was 11.5:1. Was worried too rich at peak rev but seems like had no problem.

 

[chris2000]

redza,

how's your car going??

 

[shiroitenshi]

Hmm no correct AFR really IMO, just play with ignition and fuel to get the most torque (or target torque) out.

My map ranges from 14.7 at low revs (idle I set at 15) to 12.8 at WOT, some lower revs I put about 13. someplace leaner a bit just to smooth the torque out, if ignition correction changes it too much. I tuned it for part throttle response mostly, because it's a daily driver, where it sees most at 1-4K rpm. I think I only spend like 2 hours on the WOT, but for my on road tune, I took about 4hours to experiment with the ignition for low rev response. The stock ignition is plenty good for normal engines and increasing it much does nothing (except decrease power), but it's not about the amount really, but rather 'where'. This applies for both fuel and ignition. Depending on cam setting, your peak flow will be different, and so will your peak torque.

When you see the ignition numbers on mine, they're not really that high, compared to the based map... in fact, they're actually lower (I posted it a while back) because I retarded it, and because I run it a little lean at part throttle. (which explains my very low f/c at part throttle)

It's not truly an exact science, but once you understand peak pressure, stroke leverage, piston speed, burn rates and you know what ignition and fuel adjustment does, and you'll find there's not really an ideal AFR. The ideal AFR (which is not a static value) is the one you get the most power out without overheating and seizing your engine.

 

[hattech-v]

actually very hard to blown any n/a engine by afr tuning fault... it is not very sensitive compared to turbo or any other engine piston...
very hard to see any honda piston melting coz running lean... still got but rarely seen...
most of the time the damage caused by the mechanical failure like piston touching valve, sleeve crack etc...

 

[shiroitenshi]

actually very hard to blown any n/a engine by afr tuning fault... it is not very sensitive compared to turbo or any other engine piston...
very hard to see any honda piston melting coz running lean... still got but rarely seen...
most of the time the damage caused by the mechanical failure like piston touching valve, sleeve crack etc...

Yeah, but that's because we're not running extremely high comp.
Try 12+ CR, and see if someone doesn't seize pistons by tuning fault. (ring overheated, ring gap < 0, you know the rest)

Melting pistons, now that's not common for NA.. cracked sleeves.. well.. I'm sure you know how many people go overboard with reboring the slock sleeves.. >P

a lot of mechanical failure probably because some people running stock oem parts still want to rev past 9K.. lol.

I wouldn't blame them tho.. the temptation is always there when you have rev limit control in your own hands.. lol.

Still, right now getting my head around gear ratios.. got a good ratio idea going for full throttle shift, but the price, OMG!

I just tried full throttle shift and realized you need custom gears for it to work.. alamak!

Should finish everything on my car by january, then I'm going to dyno it and see how it goes.

 

[eddie_vtec]

my cruising 18.5 - 15.5...WOT 13.5 - 12.5....

 

[udengfahlawi]

redza,

how's your car going??

not yet ler...

 

[lan evo]

heres the chart

b16a
stock airbox with arc intake chamber
spoon plug cable
itr intake manifold
itr cam
stock extactor
ported n polish and skim head
chipped ecu with cheap chip

only134whp

 

[hattech-v]

yalaaa.... building 250atw monster take a lot of time.... hahaha

 

[hattech-v]

lan, it can be fine tuned...