|
Re: Tuning Results From An O2 Kit?
[Re: davenc]
#937153
03/23/12 07:29 PM
03/23/12 07:29 PM
|
Joined: Apr 2008
Posts: 90
NL
Frederick
member
|
member
Joined: Apr 2008
Posts: 90
NL
|
Quote:
I think the primary author of that thread where you took those illustrations would rather disagree with your fourth sentence. One of Tuner's points is that emulsification is not a primary goal. Also the top emulsion-hole and 'kill bleed' hole are used in the main circuit to vary the initial pressure drop. Here's the thread, Mr Tuner sir, Holley emulsion holes? you can decide for yourselves. Motorhead's graphic will show up in the second thread linked at the end of that one.
Mattax,
Thanks for clearing that up.
I'm no expert, didn't know anything about Holley's until a year ago. But trying to learn more everyday.
Can't find it anymore, but the statement I made came from the innovate forum too.
Agreed lot's of good reading there.
Quote:
Fredrick,
I think what you and Dave have been discussing is basically correct. And agreed you have to get the float fixed because that's effecting the pressure head and everything in the wells.
My only additional recommendation is to determine the HSAB based on the wide open throttle acceleration through the top of the RPM and load range. Your engine may be perfectly fine going to 16:1 AFR before the PV kicks in. It depends on the engine and the load. If you hold it at that point and it goes flat and loses power, then its too lean. In that case, adjust the main jets or open the power valve sooner.
Also take a look at your the spark plugs after doing that.
PS. As you may have seen on the Innovate forum, I found it useful to do testing with the secondaries disconnected.
Thanks, good to know I'm on the right track.
Am I correct in understanding that with a flat fuel curve of say 12.5 at WOT the mixture will still go lean on medium acceleration before the PV opens?
And that if you get problems you can't fix them with a different air bleed?
I'm genuinely interested in this and I haven't been able to find anything on this on the innovate forum.
Only that Tuner said the it's normal the mixture would go lean before the PV opens, but not why or how to solve it.(if it becomes a problem)
383B, 9.8:1, Lunati 60302(220/226@0.050 262/268Dur, 0.475"/0.494", Stealth heads, Performer manifold, QF SS-750-AN carb, 3.31Diff, A833 4-speed manual.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Frederick]
#937154
03/24/12 12:01 AM
03/24/12 12:01 AM
|
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax
top fuel
|
top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
|
You're welcome. Glad I could help on that one. Let's face it. This is a tough subject to explain clearly, and then sometimes even the most knowledgable ones either misunderstand or mistate, or just jump in their thinking in way its hard to follow. Quote:
Am I correct in understanding that with a flat fuel curve of say 12.5 at WOT the mixture will still go lean on medium acceleration before the PV opens?
Correct. That is the way fuel delivery is normally set up. Perhaps the best graphic of that is the one from Obert in Tuners post.
Quote:
And that if you get problems you can't fix them with a different air bleed?
If you're asking about part throttle problems, I wouldn't say can't, but it didn't fit the description of the problem you described.
As you saw in both those charts that you referenced, the main air bleed has the most impact on the mixture when the circuit starts to operate and as it gets toward maximum flow. My experience and observations has been that the main circuit is providing most of the fuel when holding a steady speed around 60 mph (3000 rpm). In otherwords, around this point it has just fully taken over from the idle circuit. Changing the main air bleed (MAB) will likely start the mains a little sooner or a little later. But it will also effect the mix at the top of the rpm range.
So if you've got a nice flat AFR at WOT, and you change the MAB, it will effect the AFR at the top of the WOT. In my thread A little Dyno Fun: Disconnecting Secondaries you can see that the Primary MAB is pretty close but the Secondary MAB (and or e-holes) are not a good match.
The situation you described was that getting maybe 70% into the throttle, the load was too much for the lean AFRs. Looking back at Tuner's post #17 linked above, see the pages from Larew and Taylor have need to go richer at different loads. The one engine needs richer mixture at near 90% maximum load where the other somewhere around 70%. So your PV is opening by 90% load, but maybe not at 70% load. A higher power valve woild take car of that.
I'll also attach an AFR table (using E10 pump gas) from my own setup last September. It's not perfect by any means but gives you an idea of the relationship with vacuum and rpm. It includes only data from when the throttle was steady. The larger vacuum numbers for any given rpm are when the engine is light coasting and very light (nearly closed) throttle. [right click to see it full size}
Somewheres in the Innovate forums you can find some discussions of PV tuning. Some practical, some informative but unless you have access to a 4 or 5 gas analyzer, just informative. I've spent hours there digging back to the begining. Slowly I've absorbed some of it.
Last edited by Mattax; 03/24/12 12:08 AM.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Mattax]
#937155
03/24/12 07:45 AM
03/24/12 07:45 AM
|
Joined: Jan 2003
Posts: 5,443
Indiana
YO7_A66
OP
master
|
OP
master
Joined: Jan 2003
Posts: 5,443
Indiana
|
Mattax
""you can see that the Primary MAB is pretty close but the Secondary MAB (and or e-holes) are not a good match.""
When do you know (per the chart) when to tune the PMAB versus the SMAB?
(Is it at the 3400rpm per your chart?
Thank you
1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: YO7_A66]
#937156
03/24/12 09:49 AM
03/24/12 09:49 AM
|
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax
top fuel
|
top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
|
I seperated the Primary MAB (aka HSAB) from the Secondaries based on the dyno runs posted in A little dyno fun . The above table is mostly idle/transition circuit and primaries. It's possible that secondaries could have been cracking open at 3400 rpm or less, but I don't think they are in this particular chart. So first lets go to the dyno runs. Below is one of the pdfs from logworks. [You can see it better in Logworks but it also shows on the Dynojet's data, see the pdfs in the Dyno thread for these.] In this particular pair of runs, full throttle was applied just above 4000 rpm (so the transmission would not downshift). Notice the primary only run has a fairly flat AFR curve. HSAB is fine. However the run with the secondaries has an AFR curve that goes lean to rich at the start and then trends lean. (Side note: Start is around 4000+ rpm due to the test, if you look at the tests with full throttle starting in mid 2nd gear, secondareies are partially open when 3rd gear hits.) Since we know the primary WOT fuel curve is flat, the issue here is mostly if not all in the secondaries. Just based on the trending lean, the it would seem the secondary HSAB is too large. Further, its possible the lean then rich start of the secondaries is due to the secondary HSABs being too large. Then, if the secondaries are starting to open on the highway (possible with a light spring or a mechanical linkage set to open early) it would show up in the table above. In my case, when running the yellow secondary spring, it looked to me like the secondary main circuit might have been effecting normal high speed (65 mph) highway driving a little bit. In my case, it was a little lean because as we can see from the WOT run, the secondaries mains are having trouble starting up. Based on the numbers, the table above is not from a light secondary spring configuration but I'd have to check my notes. However, the heavier spring is not a solution to the secondary circuits AFR curve. Its just changing when the secondaries open, it doesn't address the curve. Once the curve is right, the opening should be seamless and then it will be easier to determine how quickly they can be brought into play and still help performance (good rsponse, more torque and power). Bottom line is that both primary and seconday HSAB should be set based on track or dyno data. edit: jpg rather than pdf attached. X axis (bottom) is Time, Vertical axis is RPM , AFR, and Vacuum.
Last edited by Mattax; 03/24/12 10:12 AM.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: YO7_A66]
#937159
03/26/12 10:09 AM
03/26/12 10:09 AM
|
Joined: Jan 2003
Posts: 5,443
Indiana
YO7_A66
OP
master
|
OP
master
Joined: Jan 2003
Posts: 5,443
Indiana
|
Since I was showing some mid-high 15's in my last test drive, I decided to swap the .064" IAB's for some .060" IABS and give it another test drive. The first A/F number is with the leaner .064" IAB's and the second A/F number is with the new .060's (all four in each case). This is a good reference as to what one IAB swap will do to the A/F reading. This one change made a .6-1.0 change in the cruise A/F readings with the outside temps only 8 degrees difference between tests:
In D (foot on the brake): 13.2-13.4 // 13.0-13.2
30: 14.2 // 13.6
40: 14.6-14.8 // 14.0
45: 15.4-15.8 // 14.4
50: 15.2-15.6 // 14.6
60: 14.4 // 14.6
3500rpms (70mph): 14.2 // 14.6
4000rpms:(apx 75mph): 14.2 // 14.4
The .060" IAB's richened the 40-50mph cruising A/F numbers away from the mid-high 15's and brought them back down to the 14's where I want them.
Since my local gas station is E10 and the Stoich for E10 is 14.1 (gasoline 14.7), it looks like I have the cruise numbers in good shape. My in D (foot on brake) numbers show the best vacuum results when I am reading 13.2/13.4. So my 30mph reading will probably stay in the 13.6-13.8 range which I can live with. The 60mph+ numbers leaned out a bit but that might be because I lowered my primary float about 1/8 turn. Both of my floats are now about 1/8" above the bottom of the sight glass for reference.
My 50mph to WOT and my 55mph to WOT (cruise to WOT) are still showing a 12.8-13.0 reading until the WOT shift point occurs at 5700rpms. I was also getting a lean hesitation at the WOT downshift which I can easily fix with a pump cam adjustment on the secondary side.
My next test is to get the cruise to WOT readings back down into the low to mid 12's (E10% Stoich=12.2). Once I see what the secondary pump adjustment does to the WOT A/F number, I may reduce my secondary HSAB's down from the current .039" to .036" to see if I can "sneak-up" on the low to mid 12's. I decided to go this route instead of changing the secondary jets because I have leaned out the HSAB's as part of my primary tuning, and now I might be able to reduce the secondary HSAB's back down closer to stock (.031").
Would changing the "Secondary" HSAB's be a better choice or should I just go with the secondary jet swap?
Thanks
1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Mattax]
#937160
03/26/12 12:30 PM
03/26/12 12:30 PM
|
Joined: Apr 2008
Posts: 90
NL
Frederick
member
|
member
Joined: Apr 2008
Posts: 90
NL
|
@Mattax Thanks a lot for explaining. To be honest I'm not yet sure if there is a problem or not, but I always like to think ahead. Until now I've only been tuning at different cruise rpms. But what I haven't noticed before(not paying attention to) is that on acceleration the mixture goes lean. 15-15.5 AFR on perhaps 40-50 percent of throttle and the faster I accelerate the leaner it goes. Didn't get any stumble or pinging(I think) but it got me scared enough not to go push it any further before doing some more research and getting AFR's right at all cruise rpms. I'm going to try a smaller HSAB on the next run and cruise at higher rpms first before doing a WOT run. (HSABs from 0.033 to 0.031) Hope the float will arrive soon. 
Last edited by Frederick; 03/26/12 12:37 PM.
383B, 9.8:1, Lunati 60302(220/226@0.050 262/268Dur, 0.475"/0.494", Stealth heads, Performer manifold, QF SS-750-AN carb, 3.31Diff, A833 4-speed manual.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Frederick]
#937161
03/26/12 06:49 PM
03/26/12 06:49 PM
|
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax
top fuel
|
top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
|
Hope you're not letting the AFR numbers scare you. But when you write 'right AFRs' it seems like you're chasing numbers. Think of AFR numbers not as goals, but reference points, clues that help you figure out what is going on. Every engine will have slightly different needs. Your goals should be most economy and most power.
Urich & Fisher's Holley Carburetors and Manifolds provides a small section on part throttle tuning. It's aimed at road racing but the test methodology is to hold a vacuum in 3 or 4rth gear and measure the time it takes to accelerate over a set distance. Then do it again at a lower vacuum (more throttle) and again lower yet. Take it down to the PV opening. Then do it all again with richer or leaner jets until you get the best times. If the best jets don't match the jetting for best WOT, then adjust the PVCR.
That's pretty tricky to do safely on public streets even with a data logger, at least around here. However a dyno that can apply an eddy current load can work toward a similar test program. I tried it on inertia only but I don't think its terribly valid and its hard to control the throttle because the load isn't higher enough. There aren't too many dyno operators that are going to be this sophisticated about dyno testing and know carbs.
Simplest approach is to get best mph on the 1/4 mile. The nice thing about AFR monitoring is you can see if its changing during the WOT top gear. If it is, look at the HSABs. Then see if you can go leaner for highway cruise with the primary main jets. It won't ping at light throttle, it will lose power or rev up and down. At that point, you got to slow the car down to 50 or 55 mph and when you get back, jet richer. If you're doing WOT on an inertia dyno, jet a step or two richer before going out to the real world. I didn't one time, and thats how I got to experience what too lean feels like.
- I'm not sure if it the table I posted was clear. Throttle position is roughly a diagonal line on that table. A throttle position sensor is certainly another good tool in the datalogger arsenal. I'd like to add one.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Mattax]
#937162
03/27/12 06:24 AM
03/27/12 06:24 AM
|
Joined: Apr 2008
Posts: 90
NL
Frederick
member
|
member
Joined: Apr 2008
Posts: 90
NL
|
With right I meant pretty even at all rpm's not leaning at higher rpm's. But you're right, 14AFR at cruise and leaning out more the more you step on it do scare me. Yes, the graph was clear(Higher vacuum = lower load, Closer to 0 = higher load) However it doesn't show the leaning out at the level I'm experiencing. (15-16) 4 speed manual, so I think 1/4 mile will vary too much. But the Ulrich method would be a great idea. Thanks for that.  Finding a quiet road is much easier here than finding a drag strip. Think the nearest is about 100 miles. Do you use a throttle stop to accelerate at the same rate every time? I know logging would be a great and I've tried logging rpms with the LM1 but it's very unstable and it screws with the AFR as well.  I might have a fix for it, but not tried it yet.
383B, 9.8:1, Lunati 60302(220/226@0.050 262/268Dur, 0.475"/0.494", Stealth heads, Performer manifold, QF SS-750-AN carb, 3.31Diff, A833 4-speed manual.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: YO7_A66]
#937163
03/27/12 08:59 AM
03/27/12 08:59 AM
|
Joined: Jan 2003
Posts: 5,443
Indiana
YO7_A66
OP
master
|
OP
master
Joined: Jan 2003
Posts: 5,443
Indiana
|
My next test is to get the cruise to WOT readings back down into the low to mid 12's (E10% Stoich=12.2). Once I see what the secondary pump adjustment does to the WOT A/F number, I may reduce my secondary HSAB's down from the current .039" to .036" to see if I can "sneak-up" on the low to mid 12's. I decided to go this route instead of changing the secondary jets because I have leaned out the HSAB's as part of my primary tuning, and now I might be able to reduce the secondary HSAB's back down closer to stock (.031").
Would changing the "Secondary" HSAB's be a better choice or should I just go with the secondary jet swap? Note: My current secondary jets are 80's. This is the easy swap but I am not sure that it is the correct swap, mainly because I would be changing out the secondary HSAB's only.
Thanks
1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Frederick]
#937164
03/27/12 09:38 AM
03/27/12 09:38 AM
|
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax
top fuel
|
top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
|
Quote:
With right I meant pretty even at all rpm's not leaning at higher rpm's.
You may be on the right track. It depends on throttle position. If you are opening the throttle a bit at higher rpm, then the leaner AFR is normal. More throttle is needed to hold higher speeds steady so this is a tough variable to nail without a TPS.
Quote:
But you're right, 14AFR at cruise and leaning out more the more you step on it do scare me.
Yes, the graph was clear(Higher vacuum = lower load, Closer to 0 = higher load)
However it doesn't show the leaning out at the level I'm experiencing. (15-16)
Thats only due to the peculiarities of my setup. With more dynamic (and static) compression the motor would have more heat and more effecient combustion. It was OK on pump gas 10 years ago but now is marginal. The trend and pattern is prtty univeral, but the numbers and the PV location will vary considerably.
Quote:
Do you use a throttle stop to accelerate at the same rate every time?
Throttle stop is an interesting idea. I think the way to do it on a dyno may be to hold the throttle steady against a load and let the vacuum vary. The way I was trying it was to watch the vacuum gage and vary the throttle to 'crowd' 14"Hg then 12" then 10".
If you can get the rpm working with your logger, and maybe an extra set of eyes and ears, you can probably do this safely on pavement rather than rollers. Put it in 3rd gear and start the acceleration from 30 mph each time. Urich was recommending 30-80 mph but you could cut that top speed down if needed. You'll have the advantage of the rpm rise logged vs a stopwatch. Could it be done with throttle stop instead of vacuum gage? Don't know. I'd have to think about that. If you hold the throttle steady, the vacuum will rise with increasing rpm. So you'll not get the high load/low vacuum data in the higher rpm range.
Here's the post with dyno log of part throttle runs. When I've done crowds on the street, they are often short and not repeatable enough to compare. But it sounds like you may have the right situation to do it.
The Mike Urich and Bill Fisher Holley book is definately worth buying. There's a newer edition with Fuel Injection but you don't need that one. Urich was VP of engineering at Holley. I think that gives him a technical edge of the majority of authors.
Not sure what is up with your RPM logging. That's the big downfall of the Innovate stuff. Its not that user friendly and its a little flakey. I'm using an LM1 with the LMA3 (aka Aux box). I'm no longer using the rpm input, but the frequency channel set for rpm.
Last edited by Mattax; 03/27/12 09:50 AM.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Mattax]
#937165
03/27/12 10:26 AM
03/27/12 10:26 AM
|
Joined: Apr 2008
Posts: 90
NL
Frederick
member
|
member
Joined: Apr 2008
Posts: 90
NL
|
I was suggesting the throttle stop because I thought trying to keep a constant vacuum would mean working the throttle and hence engaging the accelerator pump. But in your logs I don't see this problem, AFRs are pretty constant. Did you disconnect the accelerator pump? Quote:
If you hold the throttle steady, the vacuum will rise with increasing rpm. So you'll not get the high load/low vacuum data in the higher rpm range.
Not even at WOT?
I was thinking you could vary the throttle stop from 10%-100% throttle.
The problem I have with connecting rpm is that it's impossible to read, it's incredibly spikey.
And it also makes the AFR spike.
I think it's electrical interference and the rpm converter not being able to handle it.
There are some threads on how to solve it on the innovate forum. I'm sure you've seen it, it involves making a pre-conditioning board to make sure the input voltage doesn't go above 5.0 Volts.
But like I said I have not tested it yet.
Quote:
I'm no longer using the rpm input, but the frequency channel set for rpm.
Any reason for using the frequency channel instead?
Quote:
The Mike Urich and Bill Fisher Holley book is definately worth buying.
I've got the Ulrich & Fisher book on Carburetors, Manifolds and Fuel Injection as well as the one by Dave Emanuel. 
The Ulrich & Fisher is better for tuning.
383B, 9.8:1, Lunati 60302(220/226@0.050 262/268Dur, 0.475"/0.494", Stealth heads, Performer manifold, QF SS-750-AN carb, 3.31Diff, A833 4-speed manual.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Frederick]
#937166
03/27/12 11:02 AM
03/27/12 11:02 AM
|
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax
top fuel
|
top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
|
Well you're right about WOT. The vacuum rise at WOT is very small especially with a four barrel. I didn't think of that.
Oh I think the throttle stop idea has potential. Its a different approach but not wrong. My thought for doing this type of testing on a dyno was similar. The dyno would need a load on it. My best low speed testing (idle circuit) was very gentle accelerations from dead stop holding the throttle steady.
I'm using the frequency channel because the rpm input died. This was after they fixed the Auxbox's built in MAP. They offered to repair but I needed to continue testing. Maybe I'll send it back now that I'm not using it for at least a few weeks.
Does the Urich version with FI still have the section on Road Race Tuning?
Last edited by Mattax; 03/27/12 11:06 AM.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Frederick]
#937167
03/27/12 12:33 PM
03/27/12 12:33 PM
|
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax
top fuel
|
top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
|
Accelerator pump was not disconnected. I think it is not apparent in the part throttle dyno logs for two reasons. First is that the throttle is already far enough open that the pump is little needed. In theory, pump shot is mostly to help the 'idle circuits' which can't respond to changes the way the mains can. Second reason is the throttle movements were gentle and relatively small. Any pump shot contribution would be spread out over the time of the throttle movement.
Attached is a screen shot of some part throttle crowds going uphill. Its a different carb, a 650 vacuum secondary that I was mucking up, err, learning on. Here it is set up with an 8.5 PV and the primary jets are too rich. But the main point is you can see a very brief lean pike with the begining of each increase in throttle. Could be the accelerator pump (or lack of it). Its a less than a second, and doesn't show on the accelerometer nor was it felt.
Only for the light part throttle was the vacuum held steady or 'crowded'.
-
edit. The few seconds notiicbly richer in the begining of the Light Part Throttle probably is from accelerator pump. Since I had lifted just before, the throttle position was starting from nearly closed. Thats a longer period than I normally see when logging the for pump shot tuning. Usually its all done in a second give or take a little.
Last edited by Mattax; 03/27/12 12:50 PM.
|
|
|
Re: Tuning Results From An O2 Kit?
[Re: Mattax]
#937168
03/27/12 12:53 PM
03/27/12 12:53 PM
|
Joined: Apr 2008
Posts: 90
NL
Frederick
member
|
member
Joined: Apr 2008
Posts: 90
NL
|
Quote:
Well you're right about WOT. The vacuum rise at WOT is very small especially with a four barrel. I didn't think of that.
Oh I think the throttle stop idea has potential. Its a different approach but not wrong. My thought for doing this type of testing on a dyno was similar. The dyno would need a load on it. My best low speed testing (idle circuit) was very gentle accelerations from dead stop holding the throttle steady.
One thing which might be a problem with the throttle stop idea is that at the same throttle position you can't put different loads on it.
A hill would give more load options, but we're kind of short of them here.
Quote:
Does the Urich version with FI still have the section on Road Race Tuning?
I think it does, but I'll check when I get home.
383B, 9.8:1, Lunati 60302(220/226@0.050 262/268Dur, 0.475"/0.494", Stealth heads, Performer manifold, QF SS-750-AN carb, 3.31Diff, A833 4-speed manual.
|
|
|
|
|
