Pontiac Street Performance
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password

 All Forums
 Pontiac Performance
 Intake / Carb and Fuel Delivery Tech
 Wideband tuning
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

2barrelpower
Sitting Bull

USA
135 Posts

Posted - 29 Jun 2015 :  3:07:02 PM  Show Profile  Reply with Quote
Has anyone ever used a wideband afr sensor to tune their carb?

http://www.amazon.com/AEM-30-4110-UEGO-Ratio-Gauge/dp/B00N3VGPYS/ref=sr_1_2?ie=UTF8&qid=1435604681&sr=8-2&keywords=afr+sensor+wideband

69FB, 350P, 9 to 1, Comp 260H, Stock Valve Train, Performer Intake, 1406 Carb, Hooker Headers, Points Style, Crane XRI, Crane PS20, TH350, stock stall, 3.08 gear, and 235/60/15 Firestones.

cortcomp
Coyote

USA
5335 Posts

Posted - 29 Jun 2015 :  3:29:54 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I did, almost that exact one. Easy enough to install. Made idle tuning quick, and after Cliff's advice on what to adjust, i leaned out my part throttle cruise with the APT screw, and i think i adjusted secondaries with a needle swap or i might have just left that rich. I felt better with the APT though, i was kind of rich cruising (12-13:1 if i recall, i went to 14.5:1. Could probably even lean more, but cheap insurance.)
Go to Top of Page

2barrelpower
Sitting Bull

USA
135 Posts

Posted - 30 Jun 2015 :  03:48:52 AM  Show Profile  Reply with Quote
cool, thanks.

69FB, 350P, 9 to 1, Comp 260H, Stock Valve Train, Performer Intake, 1406 Carb, Hooker Headers, Points Style, Crane XRI, Crane PS20, TH350, stock stall, 3.08 gear, and 235/60/15 Firestones.
Go to Top of Page

Bentwings
Tribal Scout

USA
28 Posts

Posted - 27 Jul 2015 :  08:14:17 AM  Show Profile  Reply with Quote
I have an Innovate AFR gage on the dash of my 41 Willys. It's not Pontiac but it's purpose is the same. I have a sbc supercharged.
I use both the AFR and vac gage for tuning. It's really the only practical way to tune a supercharged car for daily street use. I have close to 20k miles on this car.

I found that it takes a full half hour of driving to get everything warmed up and ready for intensive tuning. Please don't tell me your motor warms up in ten minutes, mine does too but that doesn't mean everything else is ready.

I have a complete range of air bleeds and feed restrictions plus jets and power valves for the Holley carbs. You really have to understand how the carbs work and what circuits are operating and when. The two Gages will help. I set cruise at around 14.2 and depending on load it can drift up to the low 15's. Beyond this there will be a lean surge, almost like a miss. Full throttle I get pretty far down 10.8 - 11.0. Leaner than this will get a huge possibly expensive "bang" out of supercharged motors. Unblown I'd try for 12.5-12.8 wide open throttle but the same 14.2 cruise. Midrange is still in the transition slot and barely main jets.

The Holley book is great for studying the operation of the carb.

Frankly I'm not good with QJets but the principal is the same. You just need a handfull of tune up parts.

Don't forget the ignition. Look up in the ignition threads for some good info on Pontiac. I like vac adv to preserve mpg even on my blown motor. 14.1 for 360 mile a couple weeks ago. 87 gas to boot.

I'm looking at a 61 Boniville by the way, that's why I'm here. It will get the AFR right away.
Go to Top of Page

Bentwings
Tribal Scout

USA
28 Posts

Posted - 27 Jul 2015 :  08:21:18 AM  Show Profile  Reply with Quote
quote:
Originally posted by Bentwings

I have an Innovate AFR gage on the dash of my 41 Willys. It's not Pontiac but it's purpose is the same. I have a sbc supercharged.
I use both the AFR and vac gage for tuning. It's really the only practical way to tune a supercharged car for daily street use. I have close to 20k miles on this car.

I found that it takes a full half hour of driving to get everything warmed up and ready for intensive tuning. Please don't tell me your motor warms up in ten minutes, mine does too but that doesn't mean everything else is ready.

I have a complete range of air bleeds and feed restrictions plus jets and power valves for the Holley carbs. You really have to understand how the carbs work and what circuits are operating and when. The two Gages will help. I set cruise at around 14.2 and depending on load it can drift up to the low 15's. Beyond this there will be a lean surge, almost like a miss. Full throttle I get pretty far down 10.8 - 11.0. Leaner than this will get a huge possibly expensive "bang" out of supercharged motors. Unblown I'd try for 12.5-12.8 wide open throttle but the same 14.2 cruise. Midrange is still in the transition slot and barely main jets.

The Holley book is great for studying the operation of the carb.

Frankly I'm not good with QJets but the principal is the same. You just need a handfull of tune up parts.

Don't forget the ignition. Look up in the ignition threads for some good info on Pontiac. I like vac adv to preserve mpg even on my blown motor. 14.1 for 360 mile a couple weeks ago. 87 gas to boot.

I also found that with a heated O2 sensor it's important to turn the key on but don't start until the gage in my case reads 22.4. This calibrates it and insures that cold fuel won't burn it out. Like "wait to start in diesels" . Yeah it is a pain but not nearly the pain of changing expensive O2 sensors.

I'm looking at a 61 Boniville by the way, that's why I'm here. It will get the AFR right away.

Go to Top of Page

Sparafucile
Sitting Bull

158 Posts

Posted - 28 Jul 2015 :  11:54:26 PM  Show Profile  Reply with Quote
What?
Go to Top of Page

Sparafucile
Sitting Bull

158 Posts

Posted - 28 Jul 2015 :  11:58:03 PM  Show Profile  Reply with Quote
quote:
Originally posted by Sparafucile

What?

Go to Top of Page

DanM
Buffalo

80 Posts

Posted - 24 Mar 2017 :  11:31:29 AM  Show Profile  Reply with Quote
I just bought my very own air fuel ratio gauge by AEM and I can't wait to install it then obsess over the readings for the next year's worth of weather changes and the necessary tweaks to my Quadrajet. Finally. It all comes together.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
Go to Top of Page

Blued and Painted
Chief PONTIAC

USA
3404 Posts

Posted - 24 Mar 2017 :  11:46:37 AM  Show Profile  Reply with Quote
Install it as close to the engine as feasible.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
Go to Top of Page

cortcomp
Coyote

USA
5335 Posts

Posted - 24 Mar 2017 :  3:35:49 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I had the same kit, it wasn't too out of place with the black bracket/face, and it was nice to get confirmation that everything was setup and operating well.
Go to Top of Page

DanM
Buffalo

80 Posts

Posted - 27 Mar 2017 :  10:14:02 AM  Show Profile  Reply with Quote
@Blued and Painted, I will take your suggestion. The closest I will mount the sensor will be the first section after the header collector. I'm running true dual w/o a crossover right now (probably forever) and so I will only get one bank, should be fine since I'm using a dual plane intake.

The main reason I picked the more expensive AFR brand is because it has a faceplate that will match fairly well with my existing water temp and oil pressure gauges. I just ordered a 3 gauge mounting bracket to put in place of the two singles that are currently mounted under my dash to the right of my knee to the left of the FM converter. (Original equipment sort of.)

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
Go to Top of Page

DanM
Buffalo

80 Posts

Posted - 29 Mar 2017 :  09:55:51 AM  Show Profile  Reply with Quote
Yesterday I installed my AFR gauge. Next to my auto-meter water temp and oil pressure gauges with their silver bezels and black on white faces I was able to select a face for the AFR and it looks like a long lost twin. Currently just tie wrapped in place. The three hole mounting bracket is en route from Summit.

The numbers are all over the place as the carb goes from circuit to circuit. It totally makes me realize the utility of fuel injection with real time feedback and controls (which is my field.)

Idle is lean at about 16. It's been cool up here in New Hampshire so it has remained about 16 even when warm. Today it's dryer and warmer outside so by the end of my commute the idle was down under 15.

Cruise is essentially the same as idle. With the throttle barely cracked it's mostly idle circuit anyway.

Part throttle I can see the effects of the power piston. 16:1 then bang 12:1.

Accelerator pump seems aggressive. It's squirts bursts of fuel from off-idle at 16 then jumps down to 11 or 10. Wow. I plan to relocate the pump rod to the outer hole which will calm down the pump a skosh. t.b.d.

Full throttle is 11 or less then slowly rises to 13+ as the engine winds up. I need more testing of this mode of operation because with all the wet roads I could hardly keep my tires planted. I wasn't in the mood to drive off the road at WOT at 70 mph while staring at the AFR gauge.

Overall I'm happy with my current carb setup. Yay me! I can't quite figure out why my fuel economy sucks so bad - 11.1 mpg - with my cruise like it is. Maybe when the weather gets milder I'll see my idle and cruise get even richer which might explain things. The problem I am faced with is that in cold winter air it runs lean (physics) and I used to have an off idle stumble. I corrected that with thinner primary rods (went 0.043 to 0.041). This of course will correspondingly richen my idle, off idle, and cruise which will hurt mpg.

current setup: primary jets 77 (wow), primary rods 41. Secondary rods 0.030 with custom tip (essentially DX rods) on 0.530 hanger "D".

possible setup: primary jets 74, primary rods 39. Secondary rod: DX on 0.610 hanger "U" or 0.575 hanger "M".

Changing the primary jet will also lean out the WOT at 2000 rpm. I'm not sure I need to do that. More testing needed. If my WOT at 5000 is too rich and I have to lower my rods to lean it out that will also lean out the 2000 rpm. If that's the case then I may need to keep the bigger jets to prevent lean condition at 2000 by combining the richer primary and leaner secondary.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
Go to Top of Page

cortcomp
Coyote

USA
5335 Posts

Posted - 29 Mar 2017 :  1:47:22 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
A.Pump should be super rich, it basically is dumping fuel in the carb. The idea at accel is to go rich for a moment, not maintain perfect 14.7:1. 16 is pretty lean, i'd try and adjust that out some? I'd think it'd be borderline smelling nasty (Exhaust). Per cliff, WOT can be rich, it doesn't hurt E.T., it's insurance against going lean, and you don't spend enough time at W.O.T. to worry about fuel economy.

Even at barely cracked throttle, i'd want that high 14s maybe 15s? So that and slightly leaner cruising? Tune based on feedback from cooling system, any knocking, whatever.

With the accel pump, i think if you move it to the outer hole, it MAY stumble on rapid transitions. You'll know and it won't hurt anything, easy enough to change back.
Go to Top of Page

Blued and Painted
Chief PONTIAC

USA
3404 Posts

Posted - 30 Mar 2017 :  01:25:35 AM  Show Profile  Reply with Quote
Yes, you need the big pump shot when the throttle blades drop open.
It should lean out to 14 to 1 @ max horse power rating. The rest of the time, it should average 12.5/13 to 1.
You cant run EFI numbers with a carburetor. An injector will atomize the fuel much finer. Where as a carb uses large fuel droplets thru a partially fuel soaked intake manifold to deliver fuel to the combustion chamber.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 30 Mar 2017 01:33:10 AM
Go to Top of Page

DanM
Buffalo

80 Posts

Posted - 30 Mar 2017 :  1:43:31 PM  Show Profile  Reply with Quote
Cortcomp. You said the magic words "borderline smelling nasty (exhaust)." Yes, it smells not so good and I want that to go away even at the expense of fuel economy.

Priority #1: no stinky car.

I will fix that with primary rods going from 0.041" to 0.039" or 0.037". I'll buy both. They're cheap. And another gasket to boot. Maybe even a bigger needle and seat.

Cortcomp you also said another magic word: knocking and cooling. I guess that's actually two words. Geez I've been battling a knock problem for years. This must be it. And it runs hot. Solution same as with stinky car issue. Although... I'm sure I solved my WOT knock problem with the richer secondaries but at least now I can probably add in more timing and gain a couple more HP.

I'm on it.

Regarding the ideal EFR for max HP we shall find out via the dyno. I at least finally managed to get the EFR down to 12 or below at WOT. It rises to the 13's. More testing needed.

Speaking of WOT measurements. Lot's more testing needed. Always more testing at WOT. Never enough...

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Pontiac Street Performance © 2006-2017 Go To Top Of Page
This page was generated in 0.16 seconds. This Site Sponsored By:
Powered By: Snitz Forums 2000 Version 3.4.05