Holley Tuning with an O2 Sensor

[CUDA JAS]

Over the last 4 days or so I have been working on tuning my Holley using an O2 sensor.

Tuning the carb before, I used the tried and true method on the accel pump of changing cams until I had no bog at WOT.  I was using the green cam, have no bog from idle to WOT.  The car was always a bit lazy, would not spin the tires, but would go, and realy take off at 2000 rpm.  I always atributed it to the combination of the cam, convetor and gears, being mismatched.

I saw on the O2 meter, that at WOT I was going very rich.  So I started going with smaller cams, wow what a change,  I noticed an improvement right away.

I am now down to the smallest (black cam) and although I am still reading rich when I go WOT, I am getting tire spin at take off and can finaly do a burnout. 

Now I am on to fining tuning the pump shot with diffenret nozzels.   

So if anyone was considering an O2 sensor, I would say it is worth the money!!!

[Chryco Psycho]

 

[t1971Chally]

Cuda Jas,

What brand of O2 sensor did you buy?  How easy is it to set up?

twiles

[Talkwrench]

What size / type Holley are we talking, what are your main jet sizes? narrow band O2 sensor?

[CUDA JAS]

Cuda Jas,

What brand of O2 sensor did you buy?  How easy is it to set up?

twiles

I bought a FAST digital O2 meter, used from a board member on another mopar site.

The install and set up is very straight forward, but some welding is involved.  THe meter is upgradeabe to read two sensors at one time, i am currently only using a single sensot.

What size / type Holley are we talking, what are your main jet sizes? narrow band O2 sensor?

I am currenlty runing a 750 vac secondary on a 360 / 727.  I had spent a fair amount of time last year tuning the carb using a vacuum gauge after instaling an Performer RPM intake (I went from a Torker II intake).

Here are the specs on my 360:

74 Cuda with a 360,
Eddy Performer RPM intake,
Eddy torker Plus cam,
The specs are as follows:
@050 Int dur. 222 , Ex dur. 234
Lift Int .447 Ex .450
Intake Centre line 107 Ex centerline 116.
About 9:1 compression.
Holley 750 vac secondary carb.
Dizzy has been recurved, running 22 initial, 38 total all in before 3000.
727 with stock converter
8-3/4 with 3.22s



 

[moparmaniac59]

Sounds wicked Jason!! The O2 sensor sounds like a great tool. I had my carb tuned (air/fuel mixture) on the engine dyno, but it sure would be nice to be able to tweak it using the O2 sensor. Nice work JAS!



                                                                        Matt B.

[Talkwrench]

I could be wrong but is a 750 a bit on the large side for what you've got  Did you have a flatspot off idle- take off? You did say you went a milder pump cam tho'..Mm intererseting I found the oposite when running a 600 on my 292 [Ford] Y block. Had to go a heavy blue cam and a large 35 squirter..
I must get one of those sensors, wide band..handy tool! 

[moparmaniac59]

I had a 750 Holley on my 360 and it was a bit too much, but it was a mildly built 360. I went with a 650 and it has NO stumble and screams now where it had a stumble before. It sounds like it might be a good fit for the 360 JAS has built. 


                                                                      Matt B.

[BS CUDA]

they are a good tool to have and I won't ever go with out one... If you run the single sensor units just put a bung in both sides of exhaust and switch back and forth if ya want... Mine is in the middle of my X pipe ... recomended idle is 14.7 on those things.... I'm pretty close 

I run the autometer ones.

Pro Systems SV1 - Pump Gas 540

And more importantly 12.8 at WOT. Jas - the cam profiles will only spread the fuel out across the path of the throttle -  you will need to decrease the jet sizes to lean it. I also run 50cc pumps front and rear - but the car is rarely idleing    

[Jamiez]

Not to hijack this thread, but are there any options for hooking up a wide band O2 sensor that doesn't involve welding in a bung?  I'd really like to do some tuning, but really don't want to do a lot of modifications.

[Talkwrench]

Usually mechanics have a long lead and shove it up the tailpipe, wouldn't be much to get and exhuast shop to weld it in.

[Chryco Psycho]

Not to hijack this thread, but are there any options for hooking up a wide band O2 sensor that doesn't involve welding in a bung?  I'd really like to do some tuning, but really don't want to do a lot of modifications.

the dynos will insert a sensor into the tailpipe but really the answer is no , you just need a small hole & a welded in bung to insert the O2 , you can plug it or just leave the o2 in place when you are done if you do not want to use it long term

[1970 RT Challenger 1970]

 

[CUDA JAS]

I had a 750 Holley on my 360 and it was a bit too much, but it was a mildly built 360. I went with a 650 and it has NO stumble and screams now where it had a stumble before. It sounds like it might be a good fit for the 360 JAS has built. 


                                                                      Matt B.

I have heard that comment before...but it works fine so I have no plans to change it right now.

I do plan to reduce the primary jets a step or two to lean it out overall.

Jason

[CUDA JAS]

Not to hijack this thread, but are there any options for hooking up a wide band O2 sensor that doesn't involve welding in a bung?  I'd really like to do some tuning, but really don't want to do a lot of modifications.

I have seen a clamp on O2 bung. I think it is was on the FAST website.

Jason