I was able to get a wideband O2 sensor (tailpipe sensor) to use to help with my tuning issues. I was able to help it a little bit by changing the accelerator pump position to squirt more gas, but was told that I am still running lean. This run was done under WOT on a dyno. Carb specs below.

http://members.cox.net/zr2much/a_f%20ratio.jpg

What jets should I go to? Should I richen up the primaries or secondaries, or both? Do I need a larger accelerator pump?

The carb is a Edelbrock #1411 750 cfm electric choke. My current setup is .110 primary jets with 073 x 037 metering rods (step 12 in the manual) and pink springs, and .110 secondary jets.

I am going to be running a 100 shot of nitrous (Edelbrock plate system) as well so I want to make sure I'm not lean on the carb.

Anyone??

I can't tell if you need a bigger accelerator shot. It is normal to get a lean spike when you floor it. If you added enough pump shot to get rid of the lean spike it would be so rich it would stumble.

The carb jets, however, are too lean. It's a little hard to see, but it looks like it is running 13.2 or so at high rpm. You need to get that down to 12.5.

It also looks like the primaries are leaner than the secondaries so jet the primaries up first. If it is still leaner than 12.5 at high rpm, jet up the secondaries. Sorry, never changed jets in an Edelbrock carb (is that the AFB?). Just Holleys. On a Holley I'd tell you to start with about 3 sizes larger primary and do another pull. If it was still lean at high rpm I'd tell you to go up 1-2 sizes on the secs. Don't know what that translates to in AFB speak. :)

You need to be real careful with AFR readings on a chassis dyno with the "tailpipe sniffer',,,

If the sensor isn't far enough into the pipe you can sometimes get false lean readings
Yours looks to be on the lean side but you want to jet for best power not AFR unless you are looking for mileage.
Some engines make more power at 12.5, some at 13.2,,,, there is no 'perfect" AFR in regards to power :)
I normally start with the AFR about 13.0, then jet up & then down to see what the engine "likes"
Always go rich first,, worst you can do is hurt power. The other way is not quite as forgiving sometimes :(
This is on an engine dyno, don't have a chassis dyno,,,

BTW, it appears those carbs are real ****y about air cleaners,, just putting my airflow turbine on the carb picked up over 15HP & leaned the carb from about 11.5 to 12.5,, no other changes,,,,

Thanks for the advice guys. At least I have some direction now on what to try. The motor feels real strong on the street so I'm just trying to unleash a little more power from it if possible. I'll jet the primaries up to a .113 and see what that does.

Wolfplace, I was wondering if a tailpipe sensor could give different readings compared to a sensor in the headers. It was a fairly long probe though, but its hard to say. As far as an air cleaner, I have a 14" K&N with one of their filter lids as well.

I've been thinking about picking up a LM-1 wideband O2 scanner to help with tuning. It seems like it would be invaluable for future projects as well. You guys think its worth the money?

The tailpipe probes have two problems. The first is that there's a delay from what happens in the engine until the exhaust has reached the sensor. The delay can be upto a second. Considering your whole run was probably only on the order of 10 seconds that's quite a lot.

Second, any exhaust leak you have will skew the numbers and make them read leaner.

I have a wideband O2 sensor and I highly, highly recommend them. Yes they are worth the money.

I also have the wideband LM-1. Well worth it.

IMO, there should not be that lean spike on the accel pump circuit. Mine dips down to 12.5:1 in the accel circuit, and leans to about 13:1 on the mains.

Jetting these Edelbrock carbs takes just a bit more figuring out... you do not want to just throw jets at it. You really need to do the math and calculate the effective jet sizes based on the interaction between jet and needle. That is why Edelbrock provides those graphs and tables in the tuning guide, they have just done the math for you already. But if you do the math you can come up with more combinations for better tuning. Also note that you are starting out with the lean version of the carb (EC models are leaner than manual choke). You could start out by just duplicating the 1407 jet/rod setup and/or using the tuning table for the 1407 instead of the 1411.

Perfection would be a cruise primary AFR of 14.7 and a power mode AFR of 12.5 with everything open. That 12.5 would probably be an average of maybe 13 on the primary and 12 on the secondary so there was a progressive enrichment correlating with the progressive push on the pedal. At least this would be perfection by the theoretical numbers :)

It does not seem to me like your info really provides enough info to tune all of the possibilities. How do you seperate the affects of the primaries from the secondaries for example? Since this graph was entirely done at max load you cannot tell anything about cruise AFR (note that a slow throttle opening might explain the initial spike too).

That is an interesting spike at the start. I have seen the 750 Ede take a pretty serious vacuum drop when you open it up but that should not be an issue at over 2000 RPM where your graph starts. I would look into the larger accelerator cluster, you likely have the 35 and the biggest they sell (as part of a set) is a 43. I would expect that to flatten out the spike. BTW the numbers on the cluster indicate the jet sizes: 35 is a .035 jet. So you could drill out your current cluster... but it is somewhat irreversible when you do that. I would also recheck the setup of the pump but don't try and use the Edelbrock directions/measurements. Instead make sure you are on the inside arm hole and adjust the link so the pump *almost* bottoms out at full throttle. This will give you maximum pump stroke and thus maximum pump volume.

I will agree completely with the utility of a wide band O2, especially when combined with a vacuum guage. Another you might look into besides the LM-1 is the Tech Edge units: www.wbo2.com. With their setup you could hook up RPM and MAP sensor inputs and then log all the data to a laptop while you drive. Then analyze it all you like. Even export it into a spreadsheet so you can make interesting graphs and play number games. For example what time elapses between 2000 and redline RPM in some gear. Sounds kinda like a dyno ;)

The O2 is really very educational about how things are working.

I have not had a chance to do this (have not had the dedicated time)... but for an optimal tune I would:
1. disconnect the secondary linkage.
2. make a pass with progressive throttle opening to just keep vacuum a couple of inches above the enrichment spring vacuum level.
3. adjust primary cruise needle/jet towards a max AFR of 14.7 repeating runs until I got it.
4. make a pass with snapped full throttle.
5. adjust primary power needle/jet towards a 13 AFR repeating runs until I got it, also tuning the accel pump.
6. reconnect the secondaries
7. make a pass with snapped full throttle
8. adjust secondary jet towards a 12.5 AFR (or whatever gives best power) repeating runs until I got it.

One of the things you might learn from this process is how the primary and secondary interact and how to tune for a flatter AFR curve rather than a sloping up or down curve. Or not, that might just be a characteristic of this carb.

I will agree completely with the utility of a wide band O2, especially when combined with a vacuum guage. Another you might look into besides the LM-1 is the Tech Edge units: www.wbo2.com. With their setup you could hook up RPM and MAP sensor inputs and then log all the data to a laptop while you drive. Then analyze it all you like. Even export it into a spreadsheet so you can make interesting graphs and play number games. For example what time elapses between 2000 and redline RPM in some gear. Sounds kinda like a dyno ;)


That's pretty much what the LM-1 does too, allows external data inputs for MAP, RPM, TPS, EGT, etc etc. I'd have to say though, the software for the LM-1 is more refined than the Tech-Edge. It graphs and calculates everything for you, and they did a great job of calculating everything you'd need to know. I dunno about the Tech-Edge, the LM-1 does not require a laptop while recording (which is nice).

Wolfplace, I was wondering if a tailpipe sensor could give different readings compared to a sensor in the headers. It was a fairly long probe though, but its hard to say. As far as an air cleaner, I have a 14" K&N with one of their filter lids as well.

I've been thinking about picking up a LM-1 wideband O2 scanner to help with tuning. It seems like it would be invaluable for future projects as well. You guys think its worth the money?
=
Yes the tailpipe sensor can give different readings but I can't tell you by how much.
I think it would be worth your time to install a bung at the collector to put you O2 sensor.
The LM1 with the optional RPM converter cable will also graph RPM plus 4 more 0-5 volt inputs if you need them & graph it all on your computer or read AFR or Lambda in real time & will record 44 minutes of data for you.
Pretty cool little box & it comes with a weld-in bung :thumbsup:
But to repeat there is no "perfect" AFR for best power that will work for every engine,,,

If you email me I have a couple of the LM1's in stock,,,

That's pretty much what the LM-1 does too, allows external data inputs for MAP, RPM, TPS, EGT, etc etc. I'd have to say though, the software for the LM-1 is more refined than the Tech-Edge. It graphs and calculates everything for you, and they did a great job of calculating everything you'd need to know. I dunno about the Tech-Edge, the LM-1 does not require a laptop while recording (which is nice).
I have to admit I have not looked into the LM-1 very closely before. A friend bought into the Tech Edge hardware and has been loaning me one of his.

But after running through the Innovate web literature it sounds like they are very similiar in general. I think I would characterize it as the LM-1 is more retail refined as a plug and go solution. The Tech Edge is a more open system which means if you want to spend some time figuring it out you can probably do more with it. Different strokes for different folks.

I think that personally I still prefer the Tech Edge. For one it is a bit cheaper in the full version and a lot cheaper in low-end or kit versions. I like that Tech Edge does not require an extra $$ add-on to read RPM, just hook it up to the coil input and away you go. The inputs on the TE also seem more generally useful and able to handle automotive voltages directly. As to logging and log software, I dunno. Does Innovate S/W allow configuration of inputs to map indications? The TE stuff allows you to put in a table of sensor values and the desired output so you can build in the data translation in the log definition instead of your head.

Vroom, thanks for the info. I'll take a look at the MC carb settings and go from there. I'm pretty much maxed out on the primaries on the 1411 tuning graph. The dyno guy said that the spike was normal which is why I wasn't too worried about that. So you think it isn't and I should try a larger squirter?

Wolfplace, you have an email.

The Tech Edge is a more open system which means if you want to spend some time figuring it out you can probably do more with it. Different strokes for different folks.

I think that personally I still prefer the Tech Edge. For one it is a bit cheaper in the full version and a lot cheaper in low-end or kit versions. I like that Tech Edge does not require an extra $$ add-on to read RPM, just hook it up to the coil input and away you go. The inputs on the TE also seem more generally useful and able to handle automotive voltages directly. As to logging and log software, I dunno. Does Innovate S/W allow configuration of inputs to map indications? The TE stuff allows you to put in a table of sensor values and the desired output so you can build in the data translation in the log definition instead of your head.

I looked into the Tech Edge unuts and I guess I'd like to know which one you've had experience with. The one I was looking at, the 2AO, is priced over 1K unless I've got the conversion from Australian $ incorrect. I also checked out their support message list and it seems a few folks are having problems with some of the units. They also don't seem too happy with the response they are getting from the creators of the product. I'm all for saving a few bucks so I'd like to hear your further comments.

Rod

I looked into the Tech Edge unuts and I guess I'd like to know which one you've had experience with. The one I was looking at, the 2AO, is priced over 1K unless I've got the conversion from Australian $ incorrect. I also checked out their support message list and it seems a few folks are having problems with some of the units. They also don't seem too happy with the response they are getting from the creators of the product. I'm all for saving a few bucks so I'd like to hear your further comments.

Rod
First you must have the conversion WAY off. You should be looking more in the $300-400 US range depending on model and options.

A friend picked up a 2A0 DIY and a 2B0. The 2A0 DIY always seemed a little wacky, especially compared to the 2B0. So when he reclaimed the 2B0 I bought my own and went for the 2B0. I plan to use it with my Accel Gen 6 DFI when I do the EFI conversion. I will use the narrow band output from the 2B0 to feed into the Gen 6. Much cheaper than the Accel wide band brick add-on.

Note that Tech Edge provides a range of products including several in kit or "DIY" form that you put together yourself. The support list gets the worst of the worst with a lot of folks who put one together and have problems getting it to work. I might have liked to save a few $$$ and gotten a kit myself. But I had just enough experience with my friends units that I did not want to mess with it. So I just went for the pre-built unit. I like the extra RJ-45 connector on the 2B0. It means that I can hook up a display and a PC at the same time. I have been following the support forum recently and Tech Edge seems fairly responsive all things considered. People have to remember that it is email with email delays and that TE is on the other side of the world. Response will not be immediate.

So I just went for the pre-built unit. I like the extra RJ-45 connector on the 2B0. It means that I can hook up a display and a PC at the same time. I have been following the support forum recently and Tech Edge seems fairly responsive all things considered. People have to remember that it is email with email delays and that TE is on the other side of the world. Response will not be immediate.

I really appreciate your input. I will continue to visit their forum to learn more about their products and how they're working out for other people. I'm one of those people who are at the very beginning of the learning curve on these systems.

Rod

If you have particular questions about the units you can post them on their email forum. The forum is kinda a community thing with responses coming from users as well as Tech Edge.

I understand what you mean about the learning curve though. The strength of the Tech Edge is the wide variety of capabilities. Unfortunately that may also be the weakness as well because you have to dig for all of the information to figure it out. For example there is a pretty slick PC-based data logger that has programmable guages (so you can show any of the auxiliary inputs for any application) that read in real-time. But it was written by someone else so it is not a standard part of the product. You have to poke around their web site and find the page and then download it yourself. Another example is there is no user manual provided, all documentation is various pages on their web site.

price from Tech Edge website

price description total
1 $655 2B0 package (2B0 unit, LD02, 2.6m7057cbl, LSU-7057) $655.00
Total of above goods = $655.00 -- Total of insurance $19.00
Weight for posting = 1055 grams -- Total of postage $29.00
Total of order in Australian dollars AU$703.00

What am I doing wrong? $531 US money from one of the conversion links on their site. Not bad but still more than the LM-1.

The TE unit is ok, but it's hard to beat the innovate stuff. I have an EFI system so I don't care about a gauge. I got the Innovate LC1 + a LSU4 sensor from a VW dealer. Total cost for the LC1 and the sensor was less than $200.

I also have a TE 2A0 kit laying around. I might hook it up on the other header to compare left/right.

Actually, If anyone is interested I'd be willing to part with the TE. I have the 2A0, display, 2.6 meter cable and a sensor. I'll also throw in a new weld-in bung so it would be a complete kit.

Actually you are not doing anything wrong. That *is* the price for the *full* package.

I just rechecked what the heck I ordered... turns out I deleted the display and sensor on my order and paid AU$463 with shipping and everything. I am still using a friend's display, once I have converted to and tuned the EFI I will remove the display. I also already had a sensor. I also believe you can get the sensor cheaper here in the states. Tech Edge has info on their site about part numbers and sources (like 1stvwparts.com).

Remember that this is the top of the line for Tech Edge. Yeah it is probably more expensive than the LM-1 at first look. If however you consider that to do anything beyond AFR (like RPM, manifold vacuum, exhaust temperature logging) you have to buy extra add-ons for the LM-1 then things even out or look better for the Tech Edge.

For serious/optimal carb tuning I would like to have RPM and a MAP sensor tied into the system. Then hook up the computer, start logging and go drive. You could then read and corelate everything later at your leisure with a nice cold brewski.

Actually you are not doing anything wrong. That *is* the price for the *full* package.

I just rechecked what the heck I ordered... turns out I deleted the display and sensor on my order and paid AU$463 with shipping and everything. I am still using a friend's display, once I have converted to and tuned the EFI I will remove the display. I also already had a sensor. I also believe you can get the sensor cheaper here in the states. Tech Edge has info on their site about part numbers and sources (like 1stvwparts.com).

Remember that this is the top of the line for Tech Edge. Yeah it is probably more expensive than the LM-1 at first look. If however you consider that to do anything beyond AFR (like RPM, manifold vacuum, exhaust temperature logging) you have to buy extra add-ons for the LM-1 then things even out or look better for the Tech Edge.


Thanks for confirming what I was seeing for price.