Wideband O2 and carb tuning

[Chippa]

Ok so i've been playing around with some setting as i felt my car was getting too much juice thrown into my 440 for normal driving etc so heres what i have done, please feel free to agree or disagree as i'm sharing this so i can continue to learn.

My 69' 440 is only a mild build , the cam does rob some low end vac (7-7.5 Hg in gear) 727 with 3.23 rear and 750 V/S
3310-4.(wondering if my 750 is too big??)

The 750 had a bit of a stumble off the line with the std 6.5 PV so i changed that to a 4.5....cleaned that up very well

My engine oil after only a short time was smelling pretty fueled up so i decided to dig a bit deeper to try and get my girl running a bit better as most of my driving is in the lower rpm/ cruising

So i did some real time driving with a wideband O2 sniffer up the exhaust taped it all up to the side of the car and ran the digital display to the dash along with a Vac gauge hooked up to sus out the manifold vac as i was driving and heres what i have found.

Intial light throttle taking off etc was showing me that i was going to zero vac really quick which i feel was wasting fuel when when just putting around....sticking my foot into it i was getting a reading of <0.81 at WOT into secondaries which is around 11.9 A/F so back to the workshop to play around with the Holley.

Off with the front bowl/ and metering block, changed out the P.V to a 2.5 PV to try and conserve the enrichment and changed jets from 72's to 67's....backed it out and took off bad move 
It stumbled pretty bad and was above 1.0 so around the block and back in and changed out jets up to 69's


Much better, lost the hesitation and light throttle slow driving was .97 .98 good and hwy cruising was .94(13.8 A/F) at 60mph
so i guess possibly still a bit rich for cruising but i think this is where i have to stay at for the time being
i probably need to change out the metering plate to a few sizes down maybe take a little more fuel out of the secondaries???

So i continue to try and understand things a bit more - i know this is basic stuff for some but you gotta start somewhere

To those who know more any advice is welcomed    i think i did the right thing by trimming the fuel up a bit

Cheers Andrew

[lasvegas69charg]

I'm in the same boat as you. I just bought a wideband and plan on installing it this week. I'm learning how the quick fuel carb works by trial and error. I have put in a smaller power valve, larger accel pump and a larger squirter. I have solved the off line hesitation but while running it smells rich but I have set the idle mixture to max vac(12 in) at idle. I am curious what the a/f will read. I will post with my finding. Also the carb is a 750 vac sec elec choke quick fuel slayer series.

[lasvegas69charg]

i got the innovate motorsports mtx-L a/f wideband hooked up today and my results at idle and cruising is maxed out at 22.4 on the gauge and at wot it is at 16.5  I am new to this gauge but im taking it that the car is running really lean...can anyone help me with the readings?

[471_Magnum]

The 22.4 is probably an indication you've got a cylinder misfiring. Check your plugs/wires.

Innovate use to have a tuning forum that was great for these types of questions. For whatever reason, they shut it down.

I'm in the process of installing a LC-1 / SSI-4 set up on my Road Runner. I'll be logging TPS, MAP, RPM and maybe vehicle speed via some junk yard sourced sensor once I get everything hooked up.

[MSRacing89]

i got the innovate motorsports mtx-L a/f wideband hooked up today and my results at idle and cruising is maxed out at 22.4 on the gauge and at wot it is at 16.5  I am new to this gauge but im taking it that the car is running really lean...can anyone help me with the readings?

If this were an injected system a guy would guess that either you have an exhaust leak or your O2 sensors is not in the correct location.  Exhaust leaks cause havoc in Injected systems as they tell the ECU it is running lean at keep pumping fuel at it to fix it.

I would double check all your welds and look closely for a leak near the sensor.

[MSRacing89]

Ok so i've been playing around with some setting as i felt my car was getting too much juice thrown into my 440 for normal driving etc so heres what i have done, please feel free to agree or disagree as i'm sharing this so i can continue to learn.

My 69' 440 is only a mild build , the cam does rob some low end vac (7-7.5 Hg in gear) 727 with 3.23 rear and 750 V/S
3310-4.(wondering if my 750 is too big??)

The 750 had a bit of a stumble off the line with the std 6.5 PV so i changed that to a 4.5....cleaned that up very well

My engine oil after only a short time was smelling pretty fueled up so i decided to dig a bit deeper to try and get my girl running a bit better as most of my driving is in the lower rpm/ cruising

So i did some real time driving with a wideband O2 sniffer up the exhaust taped it all up to the side of the car and ran the digital display to the dash along with a Vac gauge hooked up to sus out the manifold vac as i was driving and heres what i have found.

Intial light throttle taking off etc was showing me that i was going to zero vac really quick which i feel was wasting fuel when when just putting around....sticking my foot into it i was getting a reading of <0.81 at WOT into secondaries which is around 11.9 A/F so back to the workshop to play around with the Holley.

Off with the front bowl/ and metering block, changed out the P.V to a 2.5 PV to try and conserve the enrichment and changed jets from 72's to 67's....backed it out and took off bad move 
It stumbled pretty bad and was above 1.0 so around the block and back in and changed out jets up to 69's


Much better, lost the hesitation and light throttle slow driving was .97 .98 good and hwy cruising was .94(13.8 A/F) at 60mph
so i guess possibly still a bit rich for cruising but i think this is where i have to stay at for the time being
i probably need to change out the metering plate to a few sizes down maybe take a little more fuel out of the secondaries???

So i continue to try and understand things a bit more - i know this is basic stuff for some but you gotta start somewhere

To those who know more any advice is welcomed    i think i did the right thing by trimming the fuel up a bit

Cheers Andrew

We run 13.8 at cruise with our injected motor.  So you are not far off my friend.  These are not modern engines.  Most of our EFI settings ended very close to our carb settings once it was all said and done.

13.4 idle
13.8 cruise
12.4 WOT

[lasvegas69charg]

i got the innovate motorsports mtx-L a/f wideband hooked up today and my results at idle and cruising is maxed out at 22.4 on the gauge and at wot it is at 16.5  I am new to this gauge but im taking it that the car is running really lean...can anyone help me with the readings?

If this were an injected system a guy would guess that either you have an exhaust leak or your O2 sensors is not in the correct location.  Exhaust leaks cause havoc in Injected systems as they tell the ECU it is running lean at keep pumping fuel at it to fix it.

I would double check all your welds and look closely for a leak near the sensor.

msracing89...that is what innovate motorsports said...a pin hole at the bung would cause this...I know I didn't get full weld on it

[Chippa]

Cheers for the input guys   I am going to replace my exhaust in about 3-4 months time so i think i will invest in getting some O2 sensor bungs put in and buy the Wideband gauge kit (not sure what to go for but i'm sure someone will recommend ) and upgrade my orange box ecu to an MSD streetfire or 6AL type with my std electronic dizzy which should help clean things up a little more....

The guy that was helping me out reckons i should put on a 650 spreadbore holley as it would give me more snappier  response off the line   but i think i'll stay with the 750 vac  

Chippa  

[flyinlow]

Yea , I think leaning to around 14:1 at cruise for a street car is good.  Chemically 14.7 :1 is ideal for  part throttle. richer pumps gas out the tailpipe and into the oil that has no chance of combusting. Leaner makes the engine waste power compressing extra air that has no fuel to oxidize. You do need richer for WOT for best power and detonation suppression.

My mild 440,with a wideband A/f ratio gauge idles about 13.0:1 for smoothness, part throttle around 14.5:1  and 12.5:1 WOT  . Plugs look good and the oil stays clean longer.