Tuning timing - advice?
02-15-2007, 04:04 PM
#21
0.5 BAR
Join Date: Apr 2006
Posts: 66
02-15-2007, 04:22 PM
#22
3.0 BAR
Join Date: Apr 2005
Posts: 1,521
Re: Tuning timing - advice?
hate to do it (because its honda-tech) , but http://www.honda-tech.com/zerothread?id=1555006&page=1
you should check this out too http://autospeed.drive.com.au/cms/article.html?&A=0353
you should check this out too http://autospeed.drive.com.au/cms/article.html?&A=0353
04-03-2007, 06:27 PM
#23
1.0 BAR
Join Date: Mar 2006
Posts: 266
Re: Tuning timing - advice?
12:1 or whatever number your aiming for is not the magic fuel ratio for any car. each car is going to be different yours mite like the 12:1 mine may like 11:1. the wide band just shows how much fule there is. reading the plug will tell you what the engine needs. i think this is misunderstood and alot of people just gun for a 12:1 or whatever ration there told to gun for. the wideband is a great aid for tuning a car since you can get an idea of how the cars running during the entire pull not just where it stoped at and tune out the rich/lean spots. i believe the best way is to use both methods but ultimatly only the plug will tell the whole story. im not a mad tuna but thats how i understand it after i was schooled by an old school dsm guy.
04-03-2007, 07:08 PM
#24
3.0 BAR
Join Date: Jul 2006
Posts: 2,349
Re: Tuning timing - advice?
Originally Posted by MAJORAHOLE
hate to do it (because its honda-tech) , but http://www.honda-tech.com/zerothread?id=1555006&page=1
you should check this out too http://autospeed.drive.com.au/cms/article.html?&A=0353
you should check this out too http://autospeed.drive.com.au/cms/article.html?&A=0353
If i didnt just by some ear muffs i would try that ----!
04-03-2007, 11:29 PM
#25
0.0 BAR
Join Date: Feb 2003
Posts: 0
Re: Tuning timing - advice?
Originally Posted by dirtygsr94
12:1 or whatever number your aiming for is not the magic fuel ratio for any car. each car is going to be different yours mite like the 12:1 mine may like 11:1. the wide band just shows how much fule there is. reading the plug will tell you what the engine needs.
If you have a precise enough wideband and nothing is wrong with your tuning setup such as exhaust leaks or electrical grounds, then past 11.5:1 on a liquid cooled engine is typically a waste of time. A lot of engines with weak ignitions will misfire in the 11's. Aircooled you normally shoot for mid-10's. A lot of it depends on how much cylinder pressure you have. On that note, I'd like to state that extremely small bore engines like the D16 you can run super rich and the engine likes it with no misfires or loss of power... I've repeated the phenomena where you take out timing and coolant temperatures drop while power increases, and B-series or H-series taken to the point you have a uselessly large amount of power don't do this. The 248 whp (mustang) @ 12 psi was in the mid-11's, you can't make any power on a K-series at that AFR.
But, yeah, plugs! The more I read them the more I love them. It's such a black art, and the sort of camera that would take good pictures of a tiny spark plug tip is about 27th on my list of things to buy. Hrm, with the grand I'm getting back from the gummint for pursuiing my higher education I might buy a camera and rig a magnifying fixture to snap picutres of plugs. It'd be a nice writeup.
04-03-2007, 11:45 PM
#26
1.5 BAR
Join Date: Apr 2006
Posts: 676
Re: Tuning timing - advice?
Joseph, why would an exhaust leak make a difference? AFR is simply an air to fuel ratio correct? So the actually leaking of exhaust is not a problem as the ratio will remain the same unless you add air or lose exhaust, and since the air/exhaust is homogeneous mixture, the exhaust and the air is leaking not just the exhaust. Now the only thing I can think of is air being drawn into the exhaust stream. I can't really see that happening either, so if you could explain it to me that would be great, but I really can't see how an exhaust leak will change the wideband's reading in any significant manner.
04-03-2007, 11:51 PM
#27
0.0 BAR
Join Date: Feb 2003
Posts: 0
Re: Tuning timing - advice?
Widebands don't read AFRs in the chamber, they read exhaust oxygen content. Due to the pulsation of exhaust gas, it is possible for a crack in the exhaust to throw off wideband readings. Generally speaking, a small hole will only throw off readings at idle (no pressure), but I'm what they call a high tone ---- son of a bitch and I don't ---- around. Most everything I've seen that leaked got a lot worse real quick - fix the car, it's a waste of my time to deal with it.
Even if there is significant pressure in the exhaust, and if the flow dynamics and the crack are just right, then Bernoulli's Law goes into full effect. Think venturis. Think pitot tubes. Think slashcuts in the downpipe for crankcase ventilation. Think erroneous sensor readings and bottom end fuckage.
Even if there is significant pressure in the exhaust, and if the flow dynamics and the crack are just right, then Bernoulli's Law goes into full effect. Think venturis. Think pitot tubes. Think slashcuts in the downpipe for crankcase ventilation. Think erroneous sensor readings and bottom end fuckage.
04-04-2007, 12:00 AM
#28
1.5 BAR
Join Date: Apr 2006
Posts: 676
Re: Tuning timing - advice?
We could get incredibly ---- with this if we want. At the point where the exhaust velocity reaches high enough speeds to draw air in from the outside through the crack, it is no longer an exhaust leak. So what is it?
04-04-2007, 12:36 AM
#30
Guest
Posts: n/a
Re: Tuning timing - advice?
Originally Posted by Joseph Davis
Meh, yes and no. Wideband only reads indicated AFRs, not exact ones. There is a lot that throws off readings.
If you have a precise enough wideband and nothing is wrong with your tuning setup such as exhaust leaks or electrical grounds, then past 11.5:1 on a liquid cooled engine is typically a waste of time. A lot of engines with weak ignitions will misfire in the 11's. Aircooled you normally shoot for mid-10's. A lot of it depends on how much cylinder pressure you have. On that note, I'd like to state that extremely small bore engines like the D16 you can run super rich and the engine likes it with no misfires or loss of power... I've repeated the phenomena where you take out timing and coolant temperatures drop while power increases, and B-series or H-series taken to the point you have a uselessly large amount of power don't do this. The 248 whp (mustang) @ 12 psi was in the mid-11's, you can't make any power on a K-series at that AFR.
But, yeah, plugs! The more I read them the more I love them. It's such a black art, and the sort of camera that would take good pictures of a tiny spark plug tip is about 27th on my list of things to buy. Hrm, with the grand I'm getting back from the gummint for pursuiing my higher education I might buy a camera and rig a magnifying fixture to snap picutres of plugs. It'd be a nice writeup.
If you have a precise enough wideband and nothing is wrong with your tuning setup such as exhaust leaks or electrical grounds, then past 11.5:1 on a liquid cooled engine is typically a waste of time. A lot of engines with weak ignitions will misfire in the 11's. Aircooled you normally shoot for mid-10's. A lot of it depends on how much cylinder pressure you have. On that note, I'd like to state that extremely small bore engines like the D16 you can run super rich and the engine likes it with no misfires or loss of power... I've repeated the phenomena where you take out timing and coolant temperatures drop while power increases, and B-series or H-series taken to the point you have a uselessly large amount of power don't do this. The 248 whp (mustang) @ 12 psi was in the mid-11's, you can't make any power on a K-series at that AFR.
But, yeah, plugs! The more I read them the more I love them. It's such a black art, and the sort of camera that would take good pictures of a tiny spark plug tip is about 27th on my list of things to buy. Hrm, with the grand I'm getting back from the gummint for pursuiing my higher education I might buy a camera and rig a magnifying fixture to snap picutres of plugs. It'd be a nice writeup.
Ive got a question though. Do little black specks on fairly clean porclin meen detonation?
