Let's get this B**** tuned!

[GearAddict]

I've had a hell of a time getting my RR running smooth, I've been all over the map on tuning and up till recently it was starting to feel like I was just throwing darts. So I bit the bullet and bought a UEGO Wideband O2 gauge and had the bungs installed this morning.

My goal is to get the carb and timing working as optimal for street use as possible.

383, 4 speed, MP 509 cam, Holley 670 Street Avenger carb (changed Power Valve to 3.5) , MSD 6A and MSD Ready to Run Dist w/vac advance hooked to timed port.

I hooked up the meter, temporarily outside of the car, and warmed the motor up to operating temp (190) and took some baseline readings. (O2 Sensor in passenger side exhaust)

RPM Idle 1K
Vac 7
Air/Fuel 14 (fluctuated from 13.6-14.2)

I haven't taken a timing reading yet, but It was set at about 20 initial last I checked.

Some observations....
When I blipped the throttle the air fuel would go to 11:1-12:1 range (WOT)
If i raised rpms slowly to 3K (POT) it would got to 15:1

I have a new set of plugs, that I will install as soon as the car cools down and will report back on changes.

In the meantime, I'd love any help on walking through tuning her up from here.

Thanks in advance.

 

[super-bee_ski]

Cool
Great tools there!

That vacuum gage reading..is that at idle? 7 PSI?
I think that is LOW, personally.

Engine was warmed up.


Okay, I am following this thread.

 

[GearAddict]

That vacuum gage reading..is that at idle? 7 PSI?
I think that is LOW, personally..

It is low, but seems to be in line with others that are using the 509 cam... I've never been able to get it much higher than that at idle

 

[Hemi Rebel]

Doesnt look like its too far off. Need to drive it and see where its at

 

[bigmanjbmopar]

I did this same thing recently, 15 when you get it to 3k is normal lean mode blipping it and seeing 11 or less is a off throttle rich mode all normal for what you have done. When you get out on the road you will notice 12.5-15 cruising and when you drop the hammer you see it go up to 15-17 lean then let off the gas and watch it go 9-11 rich. All normal stuff.

 

[SlinktRR]

I get 9 max at 1000rpm with a .484 purple 383, so 7 is reasonable. 509 cam is big for a 383. Shoot for 13:1 at wot and 15 at cruise, light tan color on the plugs. Have fun tuning it's worth the time.

 

[Belle66]

engine tuning

I put an ACCEL DFI system on another car & used a laptop and wideband sensor to tune. This is good for drivability. For WOT I found that reading the spark plugs was the only way to be sure the engine was tuned right.

 

[GearAddict]

Here's 1 plug that is pretty representative of the other cylinders... This is still baseline reading, I replaced all plugs last night and will run and re-check.

http://www.4secondsflat.com/Spark_plug_reading.html

Based on this article, it appears I have too much timing going on? Any other thoughts?

View attachment 261662

 

[lewtot184]

if you pull back timing vacuum will decrease further. degrees probably need to be taken out of the distributor.

 

[SlinktRR]

Those plugs look like mine, slightly more rich. I run as much initial as possible to maintain decent vac but still allow for easy starts which you may also need to do with the cam you are using. You can recurve the distributor if you haven't already but you are in good shape for the street IMO. Maybe try some WOT runs and check plugs after to dial in metering for power.

 

[GearAddict]

OK.. I got sidetracked, but finally got back on this project this weekend. I temporarily wired the gauge inside the car so I could see it while driving under load.

I took her out for a drive yesterday and tried to log some results. I'm thinking I will take a video and post later this week, as the gauge is constantly moving, so at best at the moment, I can make general comments on what I saw.

1. Idle - 13.5-14.4 @ 1K

2. Short burst (2-3sec), WOT, 2nd gear, 3rd gear.. quick blip to 11:1 then hangs in the 12.5:1 - 13:1 range for the remainder of the pull. Pulled hard, with slight stumble observed on one of the pulls... I have a very light spring on the Vac Sec... maybe went too light?

3. Part Throttle cruise, held steady in the 2K-2.5K RPM range 3rd & 4th gear, Looks to run lean between 15.0 - 16.0

My initial, uneducated thought is that Idle and WOT is good? but the part throttle lean needs to be solved?

If so... can someone help me with what the best way to address is? Jetting? Is this a idle transition circuit issue?

Also, if someone has suggestion on specific conditions to record data (aside from the above steps).

Thanks in advance for the input.

 

[wvmarv]

Here's 1 plug that is pretty representative of the other cylinders... This is still baseline reading, I replaced all plugs last night and will run and re-check.

http://www.4secondsflat.com/Spark_plug_reading.html

Based on this article, it appears I have too much timing going on? Any other thoughts?

View attachment 261662

That plug looks good to me. Maybe a little on the lean side. Sure doesn't look like they need replaced.

 

[GearAddict]

Interesting... This article, seems to indicate that my readings above are in a pretty good range for the types of load tested

http://www.autospeed.com/cms/article.html?&A=1595