Innovate LM-2 for Tuning PMO Carbs
 

Folks,

I've been looking at some of the wideband / AFM tools to help tune my PMO carbs once my 3.2l engine rebuild is complete. The car is a summer daily driver with intent for Auto-X & DE.

Would like a sanity check on what I've come up with.

Considerations, thoughts & question:

1) I would prefer to tune without having to download recorded data to a computer. I have Mac computers; looks like all of the tools have associated data download reviewing applications that are Windows based.

2) From what I can tell, at a minimum I would want to monitor & record AFM and RPM.

3) I don't see any value/relevance to monitoring & recording 2 oxygen sensors (dual wideband), or swapping the oxygen sensor to check both banks on a carb'd motor. Am I wrong here?

4) I don't see the point in having a permanently installed AFM gauge in the car, other the cool looks. You can't really tune carbs from a gauge can you?

With this in mind, I've kind of narrowed down to the Innovate LM-2 basic kit. Based on my research here's my take:

Innovate LM-2 Basic Kit
Pro's:
-Unit allows you to monitor & record AFM and RPM without having to buy any additional components (you can run a wire from the coil to the LM-2 for RPM input)
-Appears you could tune from the info on the built in display - no need to download
-LM-2 has modern (USB or SD card) means to download data if desired
-Can input dual wideband if desired (buy/install additional wide Ox sensor)
-Portable. No intent to leave installed & might be able to help some of the other locals out.
-Basic kit is reasonably priced (can find for ~$250)
Con's:
-Questionable durability (lots of internet feedback showing unreliability)
-Gets rather pricy if you decide you want to add components or additional sensors later on (not necessarily for my Porsche, but my son will be 16 next year...).

Any other thoughts or considerations, or other systems in a similar price range I should look at?

Thanks, Gordo

It is not going to help you to tune the carbs. It will give you overall air-fuel ratio, but that is a final reading as to wether you are lean or rich not if one carb is rich out of the six.

Tuning involves precision adjustments to synch the carbs and to adjust air and fuel for each carburetor by measuring exhaust gasses. Unless you are going to find a way to measure the exhaust of each port then it is not going to benefit tuning.

The key to tuning with carbs is to read the plugs, find the right heat range, gap etc.

I own and use an LM2 in my 1987 930 (permanent install, but I can remove it anytime I wish) and here is my "story" about it. I bought the LM2 kit from Pelican and it only took me 4.5 years to get around to installing it (no lie). Well, right away it did not work (immediately showed an error code that indicated a problem with the heating circuit). I did not expect any warranty, or anything of the sort, as I had owned it for such a long time, and had also read all the horror stories about it, and Innovate products in general, but contacted Pelican anyway. The Pelican rep put me in touch with one of the guys in charge at Innovate, and after some email and a phone conversation with him, he asked me to ship it to them. I did so, and within two weeks, I had a new unit back in my hands with the only charge to me being the shipping cost from me to them. In other words, customer service that was way above and beyond!

So far (about 6 months) the unit has worked flawlessly. It is very easy to understand and operate, and the very large display makes it extremely easy to read day or night, and even at a decent distance.

Configure the carbs... optimizing the jetting... adjusting mixture...

Tuning?

I've got an old LM1 I use for carb tuning. I use it mainly for optimizing jetting but not so much for idle mixture.

JMHO,......

As a reality check, we tuned a LOT of carburetors quite successfully (since 1962) long before wide-band O2 sensors and instruments were invented. :) :) :)

Using simple hand tools and a few chassis dyno pulls to set the WOT fuel mixture, I think you can do this job without an LM instrument provided you are patient and are willing to learn.

O2 wide-band meters are not needed to configure the carbs; that takes VERY close attention to fuel pressure, float settings, and following some guidelines about jetting for your engine's configuration. You can set full throttle AFR's with a dyno session.

Adjusting idle fuel mixture requires a good ear and you should develop that as part of the learning process.

Just have a selection of idle jets, main jets, and air correctors on hand before starting the process. :)

I disagree on at minimum main jetting. A couple hours, a wideband, jet reamer set and an open road and I'll have the AF mix perfect on carbs.
Done it many times.

And I'd never start a new rebuilt engine without a wideband anymore, I know instantly if an engine is leaning out.
Really WB meters are so cheap now why wouldn't you use one?

BTW I don't care for the innovate meters.

Yeah way cheaper than dyno sessions.

The old school way was to read plugs but this apparently doesn't work due to fuel additives (so I am told).

Hmmnn...
 

Gents,

Thanks for the feedback - all good considerations.

A few more thoughts:

Part of the reason I went with carbs was the attractiveness of DIY tuning with basic tools as opposed to having to bring it to someone to hook it to a dyno & computer system to tune.

Meanwhile, as I researched how optimize the PMOs for my engine, I found a lot of recommendations pointing to dyno time to dial them in.

Further research has lead me to believe that I can purchase an AFM tool and optimize the carbs on my own - although I will still probably do a dyno run as a final confirmation that my carbs are good to go and to see if the engine produces the kind of torque curve I'm shooting for.

------------------------------------------

For Steve: I always appreciate your feedback and insights, but on this one, I have to respectfully comment to the contrary - I believe part of the reason you can successfully tune carbs without using a wideband tool is because you've been doing it since 1962... :)

Thanks again guys,

Gordo

Don, good luck, I think I misinterpreted your intentions. I didn't mean to sound negative.

Shane

Gordo,

LOL,..What I'm trying to say is that these are aquired skills which work better than an over-reliance on technology. In many cases, such things serve as "red herrings" which can be very misleading. :) :) :)

I recently had a client with very limited experience who struggled with his PMO tuning
by relying on his LM-2 instead of listening with his ears. All this did was build on some frustration and extend the time it took to get things dialed in.

Nobody is born with such skills and the present is usually the best time to learn. :)

Feel free to call me sometime for some details on this process.

Which Wideband meter do you like?
 

Hi Mark
What brand of Wideband meters do you prefer?

My two cents having tuned carbs for years, you don't need a wideband and it can be misleading. They work and are necessary for EFI as you can tune every cell individually, every parameter, and every condition. On a carb, you tune idle, cruise, and WOT. Your options are limited and there is interplay. A wideband can give you precise incite where precision tuning is not possible. No wideband for me. Give me a unisyn, a stopwatch, a safe measured mile, and my ears. I'm happy. In fact, I'll take a G-TECH over a wideband for carb tuning any day.

I have done a lot of Weber tuning by ear, with air flow meters, etc. I thought I was pretty good as I could always get rid of pops and snaps and backfires with seemingly strong engines that hid few problems. Nevertheless, I have been using two LM2 for tuning in the last few years. I weld in a bung on each of the 6 exhaust ports of the heat exchangers and use 2 LM2s to check AFR at idle (side to side initially) and at high rpms in steady state. I was really amazed at how far off I was on AFR on the last two rebuilds especially at start up when it sounded ok, but was really very lean. I can now quickly change main jets based on a quick reading. Once I was in the range I realized that 1/8 of a turn on the air correction resulted in big changes in AFR at idle. I am now able to tune for the entire range on AFR from idle through 5k. Certainly I see variances when I stomp it or decelerate, but now I know I am always safe. I check all six carbs with the LM2s on every port. I expect that this is more consistently scientific than the old "manual" way.

I'm going a bit simpler
 

Seriously? Am I understanding correctly - you put a wideband oxygen sensor on each exhaust port?

If that's the case, the RDT&E engineer in me loves it, but I'm way too lazy for that kind of business.

Gordo

I've never gone to that much trouble

I use a WMS meter, but they don't make them anymore, they just didn't want to compete with the cheap china units. I like the PLX and you can add other devices to them at a later date if you want.

Like everything it is just one tool in the box, I do know how to do carbs "oldschool" as well and I agree there is more to carbs than just AFR.

yes, one bung per port. I use 2 LM2s to do the side to side comparison, get them close, fine tune for the individual main and air correction jets and then check all the ports for the final tunes. I guess it's the tinkerer in me. The surprise is how much or how little the steady state AFR changes with minor changes in the jets as well as the small changes in the adjustments. This is the miracle cure for no pops, no snaps, no backfires, and no lean conditions. It takes about 2 hours to weld in the bungs and a Sat to tune to what is correct. Now, I can't say that I know exactly what is correct but dialing in 14.0 +- .5 at idle, 3k and 4.5k seems to work great with no pinging. Sometimes a bit of extra richness will cover the WOT and deceleration conditions. Before this, I discovered that one or two cylinders would have perfect air flow compared to others, but might be running lean at 15.5 or so. So, it's more about insurance and consistency and I do have time now that I am older.

This was a nice set up;

Actually its a lost less them that. About $800 (for new stuff). My next project when the engine get dropped again (on a 2 years cycle)... :D

MGL AVIONICS TC-3 THERMOCOUPLE MONITORING SYSTEM from Aircraft Spruce Canada

http://forums.pelicanparts.com/porsche-911-technical-forum/761703-12-channel-egt-cht-install.html

Velocity TC3 (half way down the page)

That is a EGT (exhaust gas temperature) system, although you can still tune with it it's different than a O2 meter.