Travis Moore
Expert
If you guys are using a good wideband with a serviceable sensor-a 11/1 AF ratio@WOT is safe, regardless of the fuel in the tank.
It seems like a lot of you guys are wanting to run things on the ragged edge to gain a few horsepower, weather it be max boost on the minumum octane, or the leanest possible AF ratio. In those situations, a slightly innacurate a/f # could very well make or break your engine.
Bottom line is run it with a wide safety margin (11/1) and plenty of MOTOR octane to keep things safe. You'll lose 10 HP and be able to hold it WOT all day vs. gaining 10 HP and wondering what is going to happen everytime you pull the trigger.
For a starting point on octane (I don't believe in the calculators, I believe in real world testing), I ran 11psi last year on my Bender stage 2 kit with AVGAS-stock engine. No problems.
T
It seems like a lot of you guys are wanting to run things on the ragged edge to gain a few horsepower, weather it be max boost on the minumum octane, or the leanest possible AF ratio. In those situations, a slightly innacurate a/f # could very well make or break your engine.
Bottom line is run it with a wide safety margin (11/1) and plenty of MOTOR octane to keep things safe. You'll lose 10 HP and be able to hold it WOT all day vs. gaining 10 HP and wondering what is going to happen everytime you pull the trigger.
For a starting point on octane (I don't believe in the calculators, I believe in real world testing), I ran 11psi last year on my Bender stage 2 kit with AVGAS-stock engine. No problems.
T
Skydog
TY 4 Stroke God
That is pretty fat , could get some rich knock.
Travis Moore
Expert
Skydog said:
No chance-but I'd say anything up to 11.5 is very safe.
TurboJamie
TY 4 Stroke God
My sled will rich knock at 11.1:1 - 11.5:1 lean it out and the knock goes away.
ken_climb
TY 4 Stroke Junkie
My wide open a/f is 10.9 with my mcx apex............ It tends to blubber off the line so I want to get it leaned out a bit. I know of a guy running a boondockers side mount and he runs his w.o.t. 14-15:1 so I'm sure if I get mine to 12:1 I'll still be safe. What do the Alpine guy's run there a/f's at?
Skydog
TY 4 Stroke God
a7m266d
How you like that knock box? How did you set it? I just put one on my sled!!
Thank you Skydog
How you like that knock box? How did you set it? I just put one on my sled!!
Thank you Skydog
TurboJamie
TY 4 Stroke God
Basically you put good fuel in it and lean it out until you see knock, this is what I did anyways. Then you KNOW its knocking adjust the sensetivity till you see knock. Then on regular fuel you will know its knocking. So for me to run on pump fuel I had 50/50 in the tank which we know shouldn't knock on pump fuel settings at 12:1 so I just ran the crap out of it a few times to get the IC hot worst case scenerio then adjusted the thing to 13:1 and adjusted the sensetivity until I saw knock. Then I put my fuel numbres back to 12:1 and no knock was present. Now on pump fuel if I see knock then I know it is really there.
I ran a stock motor @ 10 psi all winter with no problems this way.
I ran a stock motor @ 10 psi all winter with no problems this way.
Okay first time out Saturday. (bender stage 2, stock carbs)
I was running 1-2lbs of boost. 93 octane gas. (couldnt go more, blew the cooler off the sled and didnt have the wrench to tighten it back down..up front)
Anyway 30-50 mph I am running 10.5-11.5. Then I let up and it jumps to 14.5-15 and acts like its loading up. After reading this, is it leaning out???
Can someone give me a little insight on this?
Thanks, Familyman
I was running 1-2lbs of boost. 93 octane gas. (couldnt go more, blew the cooler off the sled and didnt have the wrench to tighten it back down..up front)
Anyway 30-50 mph I am running 10.5-11.5. Then I let up and it jumps to 14.5-15 and acts like its loading up. After reading this, is it leaning out???
Can someone give me a little insight on this?
Thanks, Familyman
Skydog
TY 4 Stroke God
Yea your Bender will be lean in mid range. Mine was all ways 14-15 in mid but hammer down and right to 11.5 or so.
Skydog
TY 4 Stroke God
Raise the needle alittle more,
Need for Speed 2
TY 4 Stroke Junkie
what creates the knock when rich. im curious never heard of this before. been around alot of engines never knew of such a thing. hammer can you shed some onthis please.
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