ok im gonna do an adjustable regulator and hook up a volt-meter to the o2 sensor and do some tunning from there...what i need to know is what kinda reading i should get a WOT...i remember hearing something around .900 or .750 is a good mixture...any help would be great thanks

 

Neither. You tune for HP not some reading on a gauge.

Mph at the track is a good indicator of HP.

 

yea Brent thanks but it's becoming a rare occurance that i get to the track...after some mods i went about a half second and 4 mph slower so i pulled some plugs and it's definetly lean...im gonna get to the track sat but i can't really go adjusting fuel pressure and whatnot while im there...im trying to get it in a decent tune for then so i have a better idea of what has to be done...anyone else who can possibly help w/the question i asked?...thanks

 

and if you don't tune to something you can read it is a good way to waste time hunting for an answer. the days of tuning based on tone, smell, and mph are long gone dude. i miss them, but i gotta say they are gone.
a good reading for the O2 would be in the high 800's or right around 900 in high gear at WOT.
this reading will not give you the absolute most power, that always comes from seeing how lean you can run the motor before it blows up. by tuning into this range you will make very good power with out risking any lean out in any weather condition.
this is important since the example night for your lean condition the weatehr was in the mid 40's by your last run. we are gonna get a lot of good nights like that for the rest of the year.

later
tim


------------------
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Thats absolute baloney. If you think race teams don't tune by MPH and laptimes you're mistaken. The goal is to go the fastest, not hit some O2 reading or AFR. Whatever runs the fastest is the best setting.

A gauge reading never has delivered max performance. The ONLY way to get max power is compare engine performance (as indicated by MPH or dyno) and make changes based on the trends you see.

Why would I read my O2 sensor when MPH or HP tells me exactly what I need to know? If the car runs fastest at 700mv who cares?

O2 sensors do not indicate AFR's accurately anyway. A wideband is needed for that. One car may run fastest at 900, another at 750. There aren't any magic numbers.

[This message has been edited by Brent (edited September 25, 2001).]

 

LOL, don't tell me how "race teams" tune stuff dude. i can tell you haw modern race cars, even carbed ones get tuned, it's called data logging. nascar, nhra, formula one, everybody who can afford it uses it. they don't come up with adjustmenst out of the air buddy, it is stone cold research.
yes they may decide to make an adjustment based on what they think is coming next(hang around any good stocker at an nhra event), but the bases for all of that is electronic data in any class that will allow it.
i don't know what kind of racing you are into, but i can tell you for a fact that anyone that doesn't use data acquisition on the engine is not getting everything out of it.
the same goes for the chassis in top level racing too. g meters and micro switches are all over those things. you should see allthe cool *** stuff these guys have to read over after a weekend of racing. it is some of the coolest stuff anywhere.
trust me, i was all about the low tech route for years, i hae set any number of carbs for people before from the sound of the engine or the haze on the plugs. i can do it in half the time using the same low tech adjustments(in this case fuel pressure instead of jet sizes)if i have a read of the engine runnign real time in front of me.
the only thing i still set low tech is base timing, the turn it til it pings method, and i even go back and reset that by computer later.

later
tim


------------------
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You didn't read what I wrote. Engine performance is the bottom line. Datalogging gives you clues on how to get to maximum performance, but it doesn't replace performance measurement.

You will never achieve maximum power relying on datalogging only.

Setting fuel pressure to achieve a certain O2 reading will not give you max performance.

 

brent, you said"You tune for HP not some reading on a gauge." adn that is what i responded too.
the thing you have to realize is that the reading on that gauge is HP, or at least the potential for it. it is far more accurate than a given mph(since that will change with the weather) and far more in tune with what is actually right or wrong with the engine, especially in a computer controlled application.

later
tim

later
tim

------------------
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Wrong. A reading on a gauge (O2 volts) is not HP because the O2 is not reliable for WOT and every engine likes a different WOT AFR. You cannot tune for a specific AFR. Some engines like 11:1 some like 13:1. The only way to find what AFR the engine wants is with performance measurement.

The performance of a vehicle is only gauged by it's speed or HP in a measured event.

Potential? No gauge reading indicates the potential of an engine.

You tune for gauge readings and you will never realize the potential of your car.

Computer control has nothing to do with it. An engine wants a certain AFR at WOT, carb or EFI.

It seems you have been blinded by the marketing schemes the aftermarket has thrust on us.

If my car runs faster when I raise/lower the FP/timing I don't care what the O2 reading is.

 

Let's get some things straight here. From my knowledge, plug cuts and hp are the best ways to tune any car. An o2 sensor is good for idle and light throttle, not WOT operation. At WOT the car goes instantly to 128 BLM anyways and then in PE (power enrichment) mode it does a little tuning based on the o2 sensor.
SO.... you can tune your cars idle and light throttle/cruise with an o2 sensor but don't use it over a spark plug reading! Go WOT in 3rd gear till about 3000rpm with engine load then turn off car and pull over right away. Check the number 3 cylinder spark plug, that is the best way to tune your WOT. It doesn't take much time and headers cool down pretty quick.
If you find that you're running really lean at WOT then you have 3 options Randy:

1. Bump fuel pressure
2. Get vacuum adjustable fuel pressure regulator
3. Get custom eprom

Option 1 is the cheapest BUT you'll have a super rich idle and crappy gas milage not to mention fouled plugs more frequently. Oh yeah, and let me be the first to tell you running rich with a cat converter isn't a good idea (melts carpet, ask Tim). Option 2 is a mechanical fix to your fuel starved power house. I don't think I have to say much about option 3 other than you've got mail.

------------------
, Jon (350 TBI!)
91 Red My website

 

the O2 reading is used to detrermine that. since the engine in question is a standard combination, not a radical or different package. we have all the info on what the engine needs to perform the best.
that means teh O2 sensor is like a road map to the hp. while it is great to say that the final reading of performance can only come from testing the hp, that is not always practical.
by reading what the engine is seeing through thte O2 sensor you can get the engine very close to it's best AFR.
just blindly tuning a car based on mph is wasteful and inaccurate. you can have a car lay down because it is too rich or too lean, by reading the O2 you can tell which direction it needs to go. also by looking at the O2's you can keep the car in it's best AFR easier than just trying to guess it as the weather changes.

later
tim



------------------
91 Camaro RS-LO3,Auto
New Times Coming Soon!
Check Out The East Coast F-Body Nationals Home Page
www.geocities.com/njspeeder
My MAFB.ORG Home Page
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DSI Racing Home Page
www.geocities.com/foff667

 

Wrong again. There is NO UNIVERSAL O2 VOLTAGE for max performance, stock engine or not. Period.

Practical? Good grief! If you can't measure performance, you are pissing in the wind.

You are believing a very big lie. Only performance measrurement can tell you what AFR the engine wants.


You better do some research on O2 sensors and tuning.

The purpose of datalogging is to shorten the tuning time. Not replace MPH with a reading on a gauge.