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Carb Tuning with 02 sensor?
#1227729
05/05/12 05:46 PM
05/05/12 05:46 PM
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Joined: Jan 2003
Posts: 3,862
N.E. Ohio
6bblFLASH
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,862
N.E. Ohio
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I installed an Innovate Digital Wideband 02 kit. Initial readings were 13.5 at max-throttle/power @ 78/84 jetting in a HP-950. Carb has .150 needle&seats fuel pressure steady 5.5lbs at the carb. Jetted up to 80/90`s and just got back from a "spirited" drive and the 02 is still showing 13.5 at max power. Fuel pressure is steady,it "feels" somewhat stronger{which means nothing}.  I`m really suprised 6-jets did`nt showup in the readings?  Anyone with some experience care to chime in?
70` Cuda`,440 6BBL Jerico,Dana 4.56 Still on 93 Pump Gas
9.87 @ 136/1.31-60ft.`09 Mopar Nationals PASSON PERFORMANCE "Stick-Shift" Champ!
2013 StickShift Challenge Winner@ Mopar Nationals!
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Re: Carb Tuning with 02 sensor?
[Re: 6bblFLASH]
#1227730
05/05/12 06:05 PM
05/05/12 06:05 PM
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Joined: May 2011
Posts: 4,492
northern,Ohio,USA
Clanton
master
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master
Joined: May 2011
Posts: 4,492
northern,Ohio,USA
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there is a pattern[in holley carbs]of the main jet increasing 10 sizes for every 100cfm and my 850[w/choke tower] used 87/88 jets with the power vs blocked[known to be worth 10 jet sizes]and stk jets for mine were 80s w/pvs so i realy think you should be more in the low 88/94 range unless the airbleeds make it want less. PS:Is there any chance you are boiling the fuel?[just checking]
Last edited by Clanton; 05/05/12 06:54 PM.
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Re: Carb Tuning with 02 sensor?
[Re: 6bblFLASH]
#1227732
05/05/12 08:46 PM
05/05/12 08:46 PM
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Joined: Aug 2003
Posts: 43,911
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,911
Bend,OR USA
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I'm a firm beleiver in that IF you can't jet the carb. up enough to slow the car down in the 1/4 mile MPH you don't have enough fuel  I have fought this for a long time, many things can cause a shortage of fuel delivery, to small of diameter needles and seats where the last cause  Your wide ban is probally correct on your jetting not enriching your mixture at WOT Are you running a fuel filter before the pump, better yet what are you using for your fuel supply, pump, lines, fuel filter size in microns and so on
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Carb Tuning with 02 sensor?
[Re: Cab_Burge]
#1227733
05/05/12 09:28 PM
05/05/12 09:28 PM
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Joined: Nov 2003
Posts: 5,160
Texas
dannysbee
master
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master
Joined: Nov 2003
Posts: 5,160
Texas
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Many years ago I bought a blown street car off a car lot. While it was for sale the carbs were stolen and the car lot guy replaced them with 600 holley. It ran terable and serged at a cruise. I called Gary Dyer and he told me what to do to do to the carbs. It's been 30 years ago but I do remember that the primary jets were some of the largest available and I had to drill the secondary jets to a size that he gave me. Car ran much better. I would consult with someone that is familiar with blowers with carbs.
Getting old just means you were smarter than some and luckier than others.
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Re: Carb Tuning with 02 sensor?
[Re: Dunnuck Racing]
#1227737
05/06/12 12:08 AM
05/06/12 12:08 AM
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Joined: Jun 2008
Posts: 186
Middleton, ID
curleysracecars
member
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member
Joined: Jun 2008
Posts: 186
Middleton, ID
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O2's will get you in the ballpark, but not the way to make maximum power. Tune by looking at the plugs. And, the O2 being 13.5 or more is getting to be on the lean side. Be careful.
Kyle Curley
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Re: Carb Tuning with 02 sensor?
[Re: 6bblFLASH]
#1227741
05/06/12 09:05 AM
05/06/12 09:05 AM
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Joined: Apr 2011
Posts: 321
jonestown,pa
dmking
enthusiast
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enthusiast
Joined: Apr 2011
Posts: 321
jonestown,pa
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.150 is big  can you run a vacuum guage between the carb body and the inlet of the blower? what power valve do you have in it? it has to be delivery or lean out. you have full exhaust with the o2 close to the collector i imagine? some one told me if the carb is too small for a engine you will have a hard time getting enough fuel but with the air going through it there should be a big signel at the jet and pull a lot of fuel.
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Re: Carb Tuning with 02 sensor?
[Re: dmking]
#1227743
05/06/12 09:14 AM
05/06/12 09:14 AM
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Joined: Apr 2011
Posts: 321
jonestown,pa
dmking
enthusiast
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enthusiast
Joined: Apr 2011
Posts: 321
jonestown,pa
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for fun take the rear jets out. you better see it ritchen up then it would suck if you are at the extent of the passages. on my car though 6 to 8 jet steps front to back with power valve in the front. usually is where i run at the track.
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Re: Carb Tuning with 02 sensor?
[Re: 6bblFLASH]
#1227746
05/06/12 10:10 AM
05/06/12 10:10 AM
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Joined: Mar 2007
Posts: 3,300
Northern Indiana
Dunnuck Racing
master
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master
Joined: Mar 2007
Posts: 3,300
Northern Indiana
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Quote:
Quote:
What hi speed bleeds are in yours???
Keith
I think they are .025????
I will remeasure and write it down.
As far as the fuel supply,it may not be the "best" possible set-up. But at highway speed if you just nail the pedal for a second or 3 it jumps to 13.5 and stays there. Untill I see it go richer THEN climb back to lean then yes I need to make more fuel upgrades.
I did get the cruise in range. Ended up with 75`s in the pri. and opened the PVCR up to .062 {was 052}.
So idle and cruise are acceptable,max power no.
Whats the limit of the passages in the carb. fuel wise? Like the booster stem....
Its a no-name Holley copy,casting issues?
If the bleeds are that small it won't be what I was thinking. I thought maybe you had a huge high speed bleed not letting it get enough signal.
I do remember hearing that some of the knock offs have big issues with the metering blocks and to use Holley or good aftermarket units.
I believe the main fuel channel in the emulsion circuits were the problem.
Keith
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Re: Carb Tuning with 02 sensor?
[Re: MR_P_BODY]
#1227748
05/06/12 11:28 AM
05/06/12 11:28 AM
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Joined: Jan 2003
Posts: 3,862
N.E. Ohio
6bblFLASH
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,862
N.E. Ohio
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swapped out carb for a borrowed CarbShop 950 and the problem is GONE!!!!  With the same jetting as before it is now 11.2-5 at max throttle. Fuel pressure is still at 5.5. Noticable increase in power,pulls in high pretty darn good. Odd thing is I lost 1-lb. of boost???? Went from 5.5 to 4.5????? Less cfm.?????? So now I`ll swap out peice by peice to see what is failing. The metering block suggestion makes sense Thanks for the advise 
70` Cuda`,440 6BBL Jerico,Dana 4.56 Still on 93 Pump Gas
9.87 @ 136/1.31-60ft.`09 Mopar Nationals PASSON PERFORMANCE "Stick-Shift" Champ!
2013 StickShift Challenge Winner@ Mopar Nationals!
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