no o2 sensor
- Thread starter boostindoo
- Start date
Leaner yields more power but the leaner you go the higher your EGTs also instead of combusting your exploding but what do i know :dunno:
Also gas fumes are 100X more explosive and easier to ignite then in liquid form. Yielding way more energy fuel is just one leg of the triangle
The point when gasoline is most efficient to yeild the most energy is at the peak flashpoint air ratio but no one wants explosions in the cylinder heads.
If it was really as simple as adding higher octane gas more gas to the ratio and a big park bench wing with a coffee can exhaust then every riced honda with that VtACh must be putting down 1500hp lol . . . ..
Also gas fumes are 100X more explosive and easier to ignite then in liquid form. Yielding way more energy fuel is just one leg of the triangle
The point when gasoline is most efficient to yeild the most energy is at the peak flashpoint air ratio but no one wants explosions in the cylinder heads.
If it was really as simple as adding higher octane gas more gas to the ratio and a big park bench wing with a coffee can exhaust then every riced honda with that VtACh must be putting down 1500hp lol . . . ..
Evil: I'll try again. Leaner than what? We need to have a reference point and that point is stoich. EGT peaks at stoich and falls off on either side. Note I said peak and not a particular number of degrees. The peak will be different depending on the power being made. Only when making power above 75% could the peak exceed safe limits.
Go leaner than stoich and power falls off. Go richer and power increases...to a point. Best power occurs about 150 degrees on the rich side of peak EGT, lowest emissions occurs at peak, and best fuel economy occurs about 150 degrees on the lean side of peak. As an aside peak EGT is not the the mixture where the engine generates the most heat. It's only the mixture where the exhaust gases are hottest. The engine generates most heat at best power, which results in a lower EGT. If you could control the mixture at will you could run lean of peak EGT at cruise and save a lot of fuel. I've done it on several cars. You could safely do this while making quite a bit of power. In fact the engine will run cooler and cleaner when run a bit lean.
Rich: I wouldn't call an engine producing 75% of it's rated maximum HP lightly loaded. It can be run lean at that power setting all day long without fear of damage. In fact, as stated above, it's good for it. Since you guys are usually concerned with WOT this is all purely academic.
Boostindo: None of what you're describing is a surprise. Your engine is acting just like it's supposed to with the O2 sensor disconnected.
Reaper: I dunno what the story was with yours but it should not have acted that way. I'm assuming it's not stock.
Go leaner than stoich and power falls off. Go richer and power increases...to a point. Best power occurs about 150 degrees on the rich side of peak EGT, lowest emissions occurs at peak, and best fuel economy occurs about 150 degrees on the lean side of peak. As an aside peak EGT is not the the mixture where the engine generates the most heat. It's only the mixture where the exhaust gases are hottest. The engine generates most heat at best power, which results in a lower EGT. If you could control the mixture at will you could run lean of peak EGT at cruise and save a lot of fuel. I've done it on several cars. You could safely do this while making quite a bit of power. In fact the engine will run cooler and cleaner when run a bit lean.
Rich: I wouldn't call an engine producing 75% of it's rated maximum HP lightly loaded. It can be run lean at that power setting all day long without fear of damage. In fact, as stated above, it's good for it. Since you guys are usually concerned with WOT this is all purely academic.
Boostindo: None of what you're describing is a surprise. Your engine is acting just like it's supposed to with the O2 sensor disconnected.
Reaper: I dunno what the story was with yours but it should not have acted that way. I'm assuming it's not stock.
just checked my codes, got a 25. does that mean i ran lean? probably starting to go a little lean at wot. 11.4lbs on a gt40. got too happy. not gonna hit it any more until i put in the injectors and hks super afr. the injectors are mk4 550, im assuming to pull out 33% like i would the apexi safc? further tuning will be done on the dyno.
i wouldn't pull out anything until you get it tuned or have yur own wideband. my buddy did that on the stock twins and ended up losing a bottom end
low throttle pull ~ 28-33.. high throttle pull ~ 20% and work from there (at lower boost (15-18), dont pull 20% and try to run 30 psi)
good deal guys, i got an aem wideband. so damn glad to have gotten this car to run right. only doing 11lbs on a big ass turbo, but still loving it.
It means either you ran lean for short period of time *during closed loop* or your O2 sensor is dying. Based on the 21 you had before it's likely the sensor. You can check it easily enough, either directly or using Vf. Because there's a chance something else is causing true leaness I wouldn't go boosting it too hard until you're sure.
haha reminds me of one time when i was working on my car and i guess had accidently disconnected the o2 and when i get it started again i got code 21 so i drove it and it was driving well ... but then i stopped knowing the possible dangers and just realized i had forgotten to reconnect. moral of the story
... dont drive without o2 sensor.. it wont ever help you
... dont drive without o2 sensor.. it wont ever help you
Rich said:
Your English is fine, it's your reading comprehension that sucks. Or maybe it's mine. I interpret the above statement to mean an engine producing 75% of it's rated horsepower is lightly loaded ie; "not putting that big of a load on it".
jetjock said:
Any idea how much whp you're generating when cruizing on a flat highway @75% throttle?
i know my 67 would still spool fine wiht 75% throttle.. so.. i'd say 300+ on a stock twined car 250+..Rich said:
you're hardly cruising at 75% throttle.. Fwiw i usually cruise ~ 15% throttle at highway speeds
No, it's far less than that, it's around 150 to 200 whp, depending on wheel stance/size and ride height. You are only maintaining speed, which means only drag and wheel resistance.
You're only generating lots of hp when accelerating, that's when you build up load on your engine. Drag + wheels alone can't generate that.
Throttle position doesn't determine load, there's more factors to it.
With the 'cruising' I meant maintaining speed, no accelleration. I know it's actually speeding @ 75% throttle, but thats fun
I also don't need more than 15% to get along with the traffic.
You're only generating lots of hp when accelerating, that's when you build up load on your engine. Drag + wheels alone can't generate that.
Throttle position doesn't determine load, there's more factors to it.
With the 'cruising' I meant maintaining speed, no accelleration. I know it's actually speeding @ 75% throttle, but thats fun
I also don't need more than 15% to get along with the traffic.
Sigh. One more time: 75% POWER. If an engine is rated at 1000 hp and is making 750 it's at 75% power. On a stock 230 hp Supra that would be 172.5 hp. Use whatever throttle position it takes to make that.
Sure, a car cruising on the highway uses about 25-28% of it's available power to go 60 mph, but how much hp is the engine making to cruise at 150 mph? Or whatever speed it takes to produce 75% of the engine's available hp? Load is load, whether it comes from a dyno, drag from speed, or climbing a hill. In each of those cases is the car accelerating? And do you actually think pilots in cruise flight use only around a quarter of the power available to them? 75% POWER. What's so hard to understand about that?
Sure, a car cruising on the highway uses about 25-28% of it's available power to go 60 mph, but how much hp is the engine making to cruise at 150 mph? Or whatever speed it takes to produce 75% of the engine's available hp? Load is load, whether it comes from a dyno, drag from speed, or climbing a hill. In each of those cases is the car accelerating? And do you actually think pilots in cruise flight use only around a quarter of the power available to them? 75% POWER. What's so hard to understand about that?
OK, I guess I misunderstood/misread, I get your point. Pity you must be so cocky though.
btw I didn't think or say pilots use whatever power, those are your words I never commented to that.
btw I didn't think or say pilots use whatever power, those are your words I never commented to that.
Not cocky, frustrated at having to repeat myself. Don't take it personal. It's not as if you're the only one I have to do it with. The point remains the engine can be safely run lean all day long while making that amount of power. The pilot comment came from your earlier post where you stated an airplane engine in cruise flight at 75% power "doesn't have a big load on it", same as a car cruising on the highway. Now that you understand what I was getting at you can see that's not true.