The AFR and Injector size Thread

[bardabe]

Alright seems that alot of people have that "what AFR is Ideal" question in mind and search but don't search hard enough or are just too damn lazy. no worries I have taken time out of my so called :valuable life" to write my fellow zilvians the AFR sessentials, Injector size calculator, and come common injector sizes from other cars here we go

Air/Fuel Mixture
6.0 Rich Burn limit (fully warm engine)
9.0 Black Smoke Low Power
11.5 Aproximate rich best torque at WOT
12.2 SAfest best power at WOT
13.3 Aproximate Lean best torque
14.6 Stoichiometric AFR (chemically Ideal)
15.5 Lean Cruise
16.5 Usual Best Economy
18.0 Carburated Burn Limit
22+ EFI Burn Limit

if you are further confused and don't know what to pick here are the answers
11.3 at WOT and full boost
14.6 at idle
12.2 cruise / low thorttle
__________________________________________________ _______________
Injector Size Calculator

Flow Rate = (HP x BSFCX10.5)/ (#injectors x Max Cylce)

Flow rate = CC
HP = at the flywheel
BSFC = Brake specific fuel consumption (0.55 for turbo 0.45 for N/A)

Example:
2.0 Litre SR20DET
Flow= (500HP x 0.55X10.5) / (4 cylinder x 0.8)
Flow = 902cc injectors required
__________________________________________________ _______________

these are some INjectors Sizes I have found:

Nissan RB26(DETT) 440cc, 550cc
Nissan RB25(DET), SR20(DET), VH45 370cc ,VG30(DETT) 370cc
Toyota 7MGE(T) 3SGE(T) (Light green) 315cc. (top feed)
Toyota 7MGE(yellow), 22RTE(pink), 3SGE(Green): 295cc (Top Feed) 2ZZ 370cc
Nissan VG30(DE), KA24(DE), SR20(DE), RB20(DET) 270cc (RB is top feed)
Mitsubishi 2G DSM 450cc top feed.

Originally Posted by thejapino

I can contribute this (not mine, lifted from NICO)

Top Feed
Engine Style Size Impedance* Years / Models
Nissan KA24E Top feed 260cc High S13
Nissan CA18DET Top feed 370cc Low S13
Nissan RB20DET Top feed 270cc High R32
Nissan RB26DETT Top feed 440cc Low R32/R33/R34

Mazda FC NA Top feed 460cc Low 86-87
Mazda FC NA Top feed 460cc High 88
Mazda FC NA Top feed 460cc High 89-91
Mazda FC turbo Top feed 550cc Low 86-87
Mazda FC turbo Top feed 550cc High 88
Mazda FC turbo Top feed 550cc High 89-91
Mazda FC NA Top feed 680cc Low 84-85

DSM 3000GT/Stealth turbo Top feed 360cc Low 91+
DSM Talon/Eclipse nonturbo Top feed 390cc Low 89-94
DSM Talon/Eclipse 1G Top feed 450cc Low 89-94
DSM Talon/Eclipse 2G Top feed 450cc Low 95-99
Mitsubishi Evo Top feed 510cc Low Evo 1-Evo 3
Mitsubishi Evo Top feed 560cc Low Evo 4+

Subaru WRX Top feed 420cc 02+
Subaru JDM STi Top feed 525cc 99+??

Toyota 3S-GE Top feed 295cc High
Toyota 7M-GE Top feed 295cc High Cressida, Supra mk3 NA
Toyota 2JZ-GE Top feed 315cc High Supra mk4 NA, SC/GS/IS300
Toyota 3S-GE Top feed 315cc High
Toyota 7M-GE Top feed 315cc High Cressida, Supra mk3 NA


Side Feed
Engine Style Size Impedance* Years / Models
Nissan KA24DE Side feed 270cc High S13/S14
Nissan SR20DET Side feed 370cc High S13/S14
Nissan SR20DET Side feed 480cc High S15
Nissan RB25DET Side feed 370cc High R33/R34
Nissan VG30DETT Side feed 370cc High Z32

Infiniti VH45DE Side feed 370cc High All Years

NOTE: 90 - 94 Z32 uses a style of injector that is non-compatable with KA fuel rails (still sidefeed), while 95 - 96 uses the same injector as the RB25DET and SR20DET, etc.

Mazda FD Side feed 550cc High 93-98
Mazda FD Side feed 850cc High 93-98
Mazda 20B Side feed 550cc High JDM Mazda Cosmo?

Subaru JDM STi Side feed 550cc (565cc?) High pre 99
Subaru STi Side feed 565cc High 03+

Toyota 7M-GTE Side feed 430cc (440cc?) Low Supra mk3 turbo
Toyota 2JZ-GTE Side feed 550cc Low Supra mk4 turbo
Toyota 3S-GTE Side feed 430cc (440cc?) Low MR2, 91+
Toyota 4A-GZE Side feed? 365cc Low MR2, MK1
Toyota Celica GTS Side feed? 310cc High 2000+
Toyota JDM 1JZ-GTE Side feed 430cc Low Chaser, Supra mk3?
Toyota JDM 2JZ-GTE Side feed 430cc High?* Supra mk4 turbo
Toyota JDM 7M-GTE Side feed 430cc Low Supra mk3 turbo

Ford Turbo Coupe ?? 30lb (~315cc) Low 86-89
Ford Turbo Coupe ?? 35lb (~365cc) Low ??
Honda Prelude (H22A) ?? 345cc Low 92-96 VTEC

*Impedence
Saturated = High Impedence
Peak and Hold = Low Impedence

I will add more as more information is aquired.
enjoy!

[Jordan]

Originally Posted by bardabe

these are some INjectors Sizes I have found:

Nissan RB26(DETT) 480cc, 550cc
Nissan RB25(DET), SR20(DET), VQ45,VG30(DETT) 370cc
Toyota 7MGE(T) 3SGE(T) (Light green) 315cc. (top feed)
Toyota 7MGE(yellow), 22RTE(pink), 3SGE(Green): 295cc (Top Feed)
Nissan VG30(DE), KA24(DE), SR20(DE), RB20(DET) 270cc (RB is top feed)

I will add more as more information is aquired.
enjoy!

VH45

typing for extra length...

[bardabe]

so are we going to sticky this or no?

[usdm180sx]

Good stuff

[bardabe]

So we gonna sticky this bad boy or what? lol midnight bump. and im out zilvia tired need to go pick up a FMIC tomorrow morning.

[bejota180sx]

dont know if this helps, hope it does...

but 2zz toyota engines are 370cc and 2nd gen turbo eclipse are 450cc
subaru STI injectors are 550cc(yellow)

[liv2drift045]

also i thought rb26 injectors were 440's...

good info though *thumbs up*

[lok]

1 lambda = 14.68

[bardabe]

wtf is a "lambda" lol

[SHIFT_Slide]

Lambda is just another expression for a/f mixture. It's based off the stoichiometric air/fuel ratio.

http://en.wikipedia.org/wiki/Oxygen_sensor
http://en.wikipedia.org/wiki/Air-fuel_ratio
http://www.hondata.com/techlambda.html

Just some links to help this thread.

[hijack3d]

Originally Posted by bardabe

__________________________________________________ _______________
Injector Size Calculator

Flow Rate = (HP x BSFCX10.5)/ (#injectors x Max Cylce)

Flow rate = CC
HP = at the flywheel
BSFC = Brake specific fuel consumption (0.55 for turbo 0.45 for N/A)

Example:
2.0 Litre SR20DET
Flow= (500HP x 0.55X10.5) / (4 cylinder x 0.8)
Flow = 902cc injectors required
__________________________________________________ _______________

Furthering on this, and let me know if it confuses some of you guys since I did just cut/paste from my old article on this.. but I thought it'd be good to add. I'd also like to add that, obviously, BSFC will be different for all engines, and some have actually found that the BSFC for their set up is theoretically lower than .55 estimated for turbocharged engines...

Let's insert a scenario. Hypothetically, I want 350whp from my manual transmission RB20DET-powered 240sx. What size injectors will I need? Since our calculation doesn't account for drive train loss, we're going to need to see how much of this horsepower will be at the crank. Statistics say there is a 15-17% loss for manual trannys vs a 20-25% loss for automatics. This is not set in stone, of course. You can manipulate these numbers accordingly.

We can look at this like our crank horsepower is really 15-17% LESS than what our actual horsepower is at the crank (BHP - WHP x (0.15 or 0.17)). Thinking of it like that makes my head hurt though, so we'll think of it another way: Our desired whp is actually 83-85% of our bhp. Following me so far? This is what our equation looks like:

Equation #2:
Calculating BHP
Manuals
BHP = WHP / (0.83 to 0.85)
Automatics
BHP = WHP / (0.75 to 0.80)

Continuing our Scenario:
Let's plug in our numbers to calculate what our BHP would be if we had 350 at the wheel.
BHP = 350whp / (0.83)
BHP = 422bhp

See? We need to be seeing 422hp at the crank in able to have 350hp at the wheel.

Now we need to plug our BHP into our first equation to see how big of injectors we'll really need to get.
[ 422bhp x 0.55 BSFC ] / [ 6 Injectors x 0.85 Duty Cycle ] = 45.51 lbs/min
(45.51 lbs/min) x 10.50 = 477.85cc/min

[thejapino]

I can contribute this (not mine, lifted from NICO)

Top Feed
Engine Style Size Impedance* Years / Models
Nissan KA24E Top feed 260cc High S13
Nissan CA18DET Top feed 370cc Low S13
Nissan RB20DET Top feed 270cc High R32
Nissan RB26DETT Top feed 440cc Low R32/R33/R34

Mazda FC NA Top feed 460cc Low 86-87
Mazda FC NA Top feed 460cc High 88
Mazda FC NA Top feed 460cc High 89-91
Mazda FC turbo Top feed 550cc Low 86-87
Mazda FC turbo Top feed 550cc High 88
Mazda FC turbo Top feed 550cc High 89-91
Mazda FC NA Top feed 680cc Low 84-85

DSM 3000GT/Stealth turbo Top feed 360cc Low 91+
DSM Talon/Eclipse nonturbo Top feed 390cc Low 89-94
DSM Talon/Eclipse 1G Top feed 450cc Low 89-94
DSM Talon/Eclipse 2G Top feed 450cc Low 95-99
Mitsubishi Evo Top feed 510cc Low Evo 1-Evo 3
Mitsubishi Evo Top feed 560cc Low Evo 4+

Subaru WRX Top feed 420cc 02+
Subaru JDM STi Top feed 525cc 99+??

Toyota 3S-GE Top feed 295cc High
Toyota 7M-GE Top feed 295cc High Cressida, Supra mk3 NA
Toyota 2JZ-GE Top feed 315cc High Supra mk4 NA, SC/GS/IS300
Toyota 3S-GE Top feed 315cc High
Toyota 7M-GE Top feed 315cc High Cressida, Supra mk3 NA


Side Feed
Engine Style Size Impedance* Years / Models
Nissan KA24DE Side feed 270cc High S13/S14
Nissan SR20DET Side feed 370cc High S13/S14
Nissan SR20DET Side feed 480cc High S15
Nissan RB25DET Side feed 370cc High R33/R34
Nissan VG30DETT Side feed 370cc High Z32

Infiniti VH45DE Side feed 370cc High All Years

NOTE: 90 - 94 Z32 uses a style of injector that is non-compatable with KA fuel rails (still sidefeed), while 95 - 96 uses the same injector as the RB25DET and SR20DET, etc.

Mazda FD Side feed 550cc High 93-98
Mazda FD Side feed 850cc High 93-98
Mazda 20B Side feed 550cc High JDM Mazda Cosmo?

Subaru JDM STi Side feed 550cc (565cc?) High pre 99
Subaru STi Side feed 565cc High 03+

Toyota 7M-GTE Side feed 430cc (440cc?) Low Supra mk3 turbo
Toyota 2JZ-GTE Side feed 550cc Low Supra mk4 turbo
Toyota 3S-GTE Side feed 430cc (440cc?) Low MR2, 91+
Toyota 4A-GZE Side feed? 365cc Low MR2, MK1
Toyota Celica GTS Side feed? 310cc High 2000+
Toyota JDM 1JZ-GTE Side feed 430cc Low Chaser, Supra mk3?
Toyota JDM 2JZ-GTE Side feed 430cc High?* Supra mk4 turbo
Toyota JDM 7M-GTE Side feed 430cc Low Supra mk3 turbo

Ford Turbo Coupe ?? 30lb (~315cc) Low 86-89
Ford Turbo Coupe ?? 35lb (~365cc) Low ??
Honda Prelude (H22A) ?? 345cc Low 92-96 VTEC

*Impedence
Saturated = High Impedence
Peak and Hold = Low Impedence

[50/50]

The rceng website has an excellent calculator. Just scroll down to the end and plug in your information:

your estimated bhp
# of injectors
bfsc
fuel pressure
duty cycle

and presto....the recommended injector size you need. Check it out:

http://www.rceng.com/technical.aspx?...X17A7N0t2ePHOI

[Hawaiian240]

Are the Mazda 93-98 FD3S Twin Turbo sidefeed injectors a drop in fit into the KA24DE and SR20DET OEM fuel rail?

[drftmark]

Originally Posted by Hawaiian240

Are the Mazda 93-98 FD3S Twin Turbo sidefeed injectors a drop in fit into the KA24DE and SR20DET OEM fuel rail?

I haven't looked anything up but for some reason I think they are low impendence. I am not sure though.

[steve shadows]

Lambda is a more precise measurement

[krazydriver]

I just want to point out that you don't really want to label 14.6 as the "ideal" idle AFR. While OEM often aims for that for emissions reasons, if anyone has tuned their car they will most likely not get that value.

Tuning idle fueling is really in the interests of achieving the highest vacuum possible. Done this way my car idles best at a 13.7 AFR with ~22 in of vac.
Some really crazy cammed stuff has to go as low a 12.5 sometimes.

[97KATURBOSILVIA]

Originally Posted by drftmark

I haven't looked anything up but for some reason I think they are low impendence. I am not sure though.

uuuhhhhh ^^^^^^^^^^^^ you dont need to look it up just look at first post by thread starter. It states "Mazda FD Side feed 550cc High 93-98
Mazda FD Side feed 850cc High 93-98"

FD= 3rd gen rx7 or tt rx7 93-95 for usdm