Need help with finding right jetting...

[Mike Gaines]

I do not have an air/fuel sensor gauge in my car to read A/F ratio after a run. I can't put it into neutral (reverse valve body won't allow me to get to neutral without going thru 2nd and 1st at 120mph, lol) after going thru the lights to correctly read the plugs.
What is my best alternative, if any, to get plug reading.
Summit Tech said to merely run it up to 6000 in first, click it out of first gear into neutral, shut if off and coast to a stop to read the plugs...but I dont think this is the same as a wide open run in high gear...
I have no idea if I should go "leaner" or "richer" with my jetting...is it just trial and error going up a little or down a little and see what happens with ET or MPH ?
What do you guys do...to find the best jetting

 

[440roadrunner]

I'm tellin ya. I'll start a big argument here on the "best one", but you REALLY need to commit "the bux" for a wideband setup. I use an innovate, in part because I got into EFI some time ago. Mine is an innovate, which can log events so you can see afterwards "what" and "when' something happened.

I can just about guarantee you that once you use one, you will never ever look back. This could save you an engine. Couple of years ago mine cost me just under 200 with a basic display.

 

[bobtile]

Jet up until your MPH drops. Then back off.

 

[cdr]

Bob is correct.

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I have an afr gauge, but with open headers it can be difficult to get accurate readings. so again,, what Bob said.

 

[ozymaxwedge]

I agree with Bob as well ^^ keep jetting up until your MPH drops. Test and Tune.

 

[62 Dart Convertible]

For a race car, the above suggestions are correct. If you'd like to tune all over the curve for street, there is no replacement for an AFR. They are only around $200...

 

[SUPERSTOCKRACER]

I jet down 2 sizes 1st. Depending on what my plugs look like. See if your MPH and ET get better. 9 out of 10 times you're too rich.
Lean is mean. Bobtile doesn't go fast so I wouldn't listen to him. LMOL.

 

[dvw]

Very simple. Just shut the engine off in gear. It works, thats how we do it. Thr O2 is great tool but plugs will tell true story. The O2 is a great for finding lean/rich spikes.
Doug

 

[Mike Gaines]

Very simple. Just shut the engine off in gear. It works, thats how we do it. Thr O2 is great tool but plugs will tell true story. The O2 is a great for finding lean/rich spikes.
Doug

OK...about just shutting the motor off in high gear after you go thru the traps and 120 some miles per hour and coast to a stop....does that do anything bad to the trans ???

Give me some advice on this suggestion....

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I'm tellin ya. I'll start a big argument here on the "best one", but you REALLY need to commit "the bux" for a wideband setup. I use an innovate, in part because I got into EFI some time ago. Mine is an innovate, which can log events so you can see afterwards "what" and "when' something happened.

I can just about guarantee you that once you use one, you will never ever look back. This could save you an engine. Couple of years ago mine cost me just under 200 with a basic display.

Does a AF sensor setup work ok with headers and NO exhaust system....Please weigh in on this questions guys...
I want to buy an FAST or Inovate AFR setup but dont want to waste my money if it doesnt work well with headers only and NO exhaust system going on back.

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Bob is correct.

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I have an afr gauge, but with open headers it can be difficult to get accurate readings. so again,, what Bob said.

Does an AF setup not work so well with open headers only and no exhaust pipes...let me know guys....your experiences...Thanks

 

[bobtile]

OK...about just shutting the motor off in high gear after you go thru the traps and 120 some miles per hour and coast to a stop....does that do anything bad to the trans ???

Give me some advice on this suggestion....

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Does a AF sensor setup work ok with headers and NO exhaust system....Please weigh in on this questions guys...
I want to buy an FAST or Inovate AFR setup but dont want to waste my money if it doesnt work well with headers only and NO exhaust system going on back.

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Does an AF setup not work so well with open headers only and no exhaust pipes...let me know guys....your experiences...Thanks

You weld bungs into the header collectors. You don't need a full exhaust to run the o2s.

 

[splicer]

Been running my Innovate for 3 years both with open headers and full exhaust. O2 sensor is in the collector.

With open headers, you will get bad readings at idle and cruise speeds, like on the return road, because of air reversion back into the collector.

At WOT during a run, the readings are fine because of the increased exhaust velocity.

With closed exhaust, it reads accurate all the time.

The A/F monitor has shown the result of every significant jet change I have ever made and is invaluable. I would definitely buy another Innovate.

Need any more info, I'm glad to help.

John B.

 

[SUPERSTOCKRACER]

turning your car off in gear stops the transmission pump from turning which equates to no lubrication to the trans. Not a good idea.
What do I know though. I'm the slow guy here!! :icon_rr:

 

[splicer]

Might want to think about that one a bit SSR.......when you lift your foot off the gas at 145 mph, does your engine speed drop to idle ???....No , your engine speed stays up as the cars drive train is now driving the engine and you get engine braking...the tranny pump is still being driven, just from the other end of the car.... LOL....Shutting engine off gets same result only a little more engine braking....as long as you stay in gear

John B.

 

[SUPERSTOCKRACER]

Might want to think about that one a bit SSR.......when you lift your foot off the gas at 145 mph, does your engine speed drop to idle ???....No , your engine speed stays up as the cars drive train is now driving the engine and you get engine braking...the tranny pump is still being driven, just from the other end of the car.... LOL....Shutting engine off gets same result only a little more engine braking....as long as you stay in gear

John B.

You are right. I was thinking going into free nuetral after 3rd gear and shutting off the motor. I just re read the post. My mistake,

 

[splicer]

Only if the engine is able to stop...keep thinkin about it......

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Hey, SSR, it's a bit of a mind twister at best of times...no worries LOL

 

[SUPERSTOCKRACER]

Only if the engine is able to stop...keep thinkin about it......

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Hey, SSR, it's a bit of a mind twister at best of times...no worries LOL

I'm pretty sure ,if I turn off my ignition and go into free neutral my engine & transmission pumpisn't spinning in about 3 seconds unless i'm missing something.

If I'm wrong, I'm going grab myself a Nutty Irishman and drink heavily before the Met game.:icon_jook:

 

[splicer]

Could have something to do with why towing an automatic with a dead engine on it's wheels, in neutral is a no-no....



John B.

 

[SUPERSTOCKRACER]

Could have something to do with why towing an automatic with a dead engine on it's wheels, in neutral is a no-no....



John B.

is this a trick question?

 

[splicer]

Ha,Ha,......no , just an observation....take care...

John B.

 

[68 HEMI GTS]

the pump may turn for a bit but at some point the engine will stop spinning and the pump will quit. i've had my car shut off on the big end and it made some weird *** noises while it was slowing down. not something i would recommend for your trans or your engine. if your going slow enough when you kill it the motor will shut right off. its not the same as being tied to a clutch. the O2 meter as stated is good for tweaking and seeing short bursts of lean rich spots. but just because one engine makes max power at 12.0:0 A/F another may make max power at 12.7:1. they are all different, the ET will tell you what it likes.