AFR ratio and splitting jets?

[Cope]

What AFR are folks tuning for/at?

Pump gas, 91 octane, C.A. piss....

12.8 WOT?
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I'm 10.8-1 compression.

Running iron heads, 32 deg all in by 2200 rpm.

She runs hotter than I'd like, 210 at shut down with a stock water pump and 180 T stat. Electric fan, aluminum rad (no shroud) and clean inside block, heads, rad.


Engine is a 360, running hard on the street.
4150 quick fuel, 950 CFM.

I just installed a 5.5 PV (primary PV was plugged, secondary PV still plugged)

80 primary jets and 83 secondary jets on extensions.
I'm just cracking 14 on the wide band. At WOT.

should I just keep throwing fuel at it till I get my AFR down some or till it stumbels?

I'm just wondering if its timing or a lean burn that making me run hot?



What are your thoughts?

Throw fuel at it right?

Should I not be splitting jets? Should I try to the be same jets front and rear?

 

[j par]

I try to run as close to the 14.7 at idle and about 12.5 to 12.4 at wide open throttle. Of course I got this information reading one of my hot rod magazines that had some Mopar on a Dino and doing this kind of pull and that's what they were saying that particular motor was doing well at. So I just use it for my stupid m rule of thumb for myself and it seemed to work.

 

[pishta]

yeah 14.7 at idle is fine, cruise can be a little leaner, WOT should be 12.5ish but its your motor that dictates what it likes best. Why are you running a plugged PV? (oops, just reread that you installed a 5.5) you can throw fuel at it but its will be a global (off idle) enrichment where as the PV will be a controlled low vacuum enrichment. here are some values from a site: (14.7 is generally regarded as stoich)

• 6 AFR - Rich Burn Limit (engine fully warm)
• 9 AFR - Black Smoke | Low Power
• 11.5 AFR - Best Rich Torque at Wide Open Throttle (WOT)
• 12.2 AFR - Safe Best Power at Wide Open Throttle (WOT)
• 13.3 AFR - Lean Best Torque
• 14.6 AFR - Stoichimometirc Air/Fuel Ratio Value (Stoich)
• 15.5 AFR - Lean Cruise
• 16.5 AFR - Usual Best Economy
• 18 AFR - Carbureted Lean Burn Limit
• 22+ AFR - EEC / EFI Lean Burn Limit

 

[Cope]

I want max power with out washing down my rings.

Mileage can suck it. That's not my goal.

I'm blowing the tires off now but I don't want to eat my new engine.

Primary PV was plugged, now it's a 5.5

 

[j par]

I want max power with out washing down my rings.

Mileage can suck it. That's not my goal.

I'm blowing the tires off now but I don't want to eat my new engine.

What are your plugs look like?

 

[Cope]

They look good, timing on the ground strap is a clean transition. My engine guy says they look good but my AFR says different and I'm pushing my luck making passes on the street.

Plugs just read the idle back to the shop any way. I can't do a full pull, shut down and check plugs on the street.

 

[j par]

They look good, timing on the ground strap is a clean transition. My engine guy says they look good but my AFR says different and I'm pushing my luck making passes on the street.

Plugs just read the idle back to the shop any way. I can't do a full pull, shut down and check plugs on the street.

The afr calibrated correctly? Or checked against something else?

 

[yellow rose]

How much idle vacuum at CRUISE?

What plugs? Do you have pictures?

Don't know why you only have 32* total. Sounds like the plug is too hot to start with.

Trust your plugs before the gauge. Unless you are uncomfortable reading plugs.

You can see WOT without cutting the throttle. You look at the fuel ring. The tip of the porcelain is idle and the middle is cruise.

Once you are close you can use a new set of plugs and cut the engine off.

 

[AJ/FormS]

What cam? What head ccs?

 

[roccodart440]

Air-Fuel Ratio Meter Tuning- Car Craft Magazine

Shortcut... 14.7:1 for idle. 12.5:1 to 13.2:1 at WOT. See what your combo likes best.

 

[crackedback]

Higher ethanol content skews the numbers. You might be in the low 12 range or lower for max power.

NEVER tune to a number especially for WOT. Use them only as guidelines. If you are in the area, likely OK.

If you can get to the track, tune to highest mph and observe AFR. That's where the engine is happiest,

 

[DFX 340 Duster]

He doesn't need a track if he is in the Tahoe area...........he can use the freeway!!

 

[TrailBeast]

He doesn't need a track if he is in the Tahoe area...........he can use the freeway!!

Been in a Jaguar XKE at 145 on our way to Reno for the races once.
Kinda scary with someone else driving, but it was a good road to do it on.

I would feel a lot better in the mid to high 12's at WOT and the timing as advanced as I could get it without it causing problems.

BTW, 210 isn't hot.

 

[Cope]

You don't consider 210 as hot?

What's to hot???

 

[roccodart440]

You don't consider 210 as hot?

What's to hot???

"230, then you worry"

 

[B3422w5]

What kind of fan do you have on it? Make and cfm?

 

[yellow rose]

No pictures of the plugs?

 

[TrailBeast]

You don't consider 210 as hot?

What's to hot???

"230, then you worry"

Yea 230 or when the cap can't hold it back, whichever comes first.

 

[j par]

Yea 230 or when the cap can't hold it back, whichever comes first.

That's got to be in Arizona answer for sure LOL

 

[Cope]

230 seems dam close to 210...

I'm gonna start making a fan shroud in the AM. I'll post a pic of a plug tomorrow night.

 

[j par]

230 seems dam close to 210...

I'm gonna start making a fan shroud in the AM. I'll post a pic of a plug tomorrow night.

And agreed! Too close for what I like to see.

 

[AJ/FormS]

I like 205; been there since 99

 

[j par]

I like 205; been there since 99

With a heat gun pointed at the radiator?

 

[TrailBeast]

That's got to be in Arizona answer for sure LOL

Right?
I have had mine up to 230 once before and that was doing 75 with three people in the car going up a big hill coming out of Bullhead City over by Laughlin when it was 104 degrees.

Sure as heck wouldn't want it going that high all the time though, and I agree that doing something about it is a good idea.

 

[AJ/FormS]

With a heat gun pointed at the radiator?

On the runner to the stat housing, on the backside out of the wind. Or pretty much anywhere on the aluminum head there. I run a low-pressure system (7psi), and the top of the rad always has air in it, so it reads much cooler