I have to get larger chokes and re-jet my 1911cc/dual IDF40s and was thinking of installing a wideband air-fuel gauge to help with tuning. I've looked at a few digital gauges for around $200 that include the gauge, O2 sensor, bung, wiring, etc. Wondering if you guys have any sourcing recommendations and install tips. It looks simple from what I've read. Thanks for any help you can provide.

this is the one i would get. http://www.summitracing.com/search/Brand/I...s/?autoview=SKU its the only digital one on the market i believe. mine is the older innovate gauge. its analog, but still works great. haveing a wideband is an invaluable tool for tuning.

I bought mine via Richard Clewett.com... great price and support

Try the innovate MTX. Just be sure and buy the one with the ten foot cable. The motor sports version has a cable only 3 feet long. I've had mine installed for s few months and it is very easy to tune with.

Thanks for the input. Looks like the Innovate is the one to buy...just have not decided on a permanently installed gauge or a hand-held meter for tuning. Is there a benefit to having a AF gauge for every day driving or just when tuning (other than the cool factor which I would enjoy)?

I installed the inovate sensor. It was very helpful. After awhile it is just another distraction. The manual stated that it needs to be powered up. If you use it and decide to remove it, you will want to remove the sensor and install a plug in it's place.

i have both. the lm-2 and the permanently installed gauge. i started off the lm-2 (hand held). thats what i initially used to tune my car. so it was just temped in. cord thru the window. so when i pulled it off to use on my bikes i had nothing in my car. thats when i decided to install a permanent one. two reasons..... 1. when i make any type of changes to the engine i have instant results to see if it affected my a/f ratio. and 2. i like to monitor the a/f. i like to be able to glance at the gauge when im pulling the monster grades on the freeway. it would suck to be running lean at WOT and not know it. data is everything.......to me anyways....

I installed the Innovate LMX gauge mounted using the Rennmetal ash tray replacement. Now the tuning fun begins. Does anyone know of a site or post that I can read to get a better understanding of how to proceed? I'll post the AF numbers from my drive home later today to give you an idea of where I'm starting from.

http://www.thesamba.com/vw/forum/viewtopic...asc&start=0

I have always felt the same too lean is something not to guess at.

Not to hijack but what about dual exhaust with out a crossover ? I have seen setups with 2 sensors has anyone used them?

cool....try to give us all the info you can. jetting sizes,emulsion tubes, venturi sizes, distributor, etc.

A little late to the party but the digital wideband gauge I sell is not made by Innovate.
After my experience with the Innovate LM-2 I avoid anything made by them.

Chris, could you expand on this?





As for me, I have some recent experience with PLX Devices modules and was happy with the results.

I bought the LM-2 because we needed a wideband setup which could be installed in a car with no O2 fitting in the exhaust. The popular LM-1 had been recently discontinued and the LM-2 was being promoted as the replacement. Ok, for the increased price we got two sensors and a nice data logger with rpm recording.
The rpm feature was just about totally useless - it didn't work with most ignitions - and Innovate's first answer was to tell everyone to purchase another one of their devices which could read a raw signal from a coil and turn the signal into something the LM-2 could understand. In spite of numerous complaints on their technical forums, their next best answer was a vaguely outlined signal conditioning device one could make from pieces purchased at Radio Shack. (the circuit included a 0-10,000 ohm, 10 turn pot.)
We built the signal conditioner and tested the LM-2 on a variety of 914s with various ignitions. We tried numerous times to apply their (Innovate techies) "expertise" so we could drive a car and record O2 and rpm for tuning purposes. I think we were able to obtain useful rpm data from one of the systems we tested on. I sure as hell wasn't going to spend another $200 on one of their other devices after spending $500 on something marketed as a complete product, which didn't work as promised.
At one point we flashed the LM-2 with updated firmware which was touted as their final solution to the problem - but that didn't work either.

There was another problem too. The clamp which held the O2 sensor in the tailpipe wasn't very secure and once it came out while we were driving & monitoring AFR. The sensor and clamp dragged on the ground, the cable caught a wheel, and the assembly swung up and dented the customer's fender.
Innovate can go to hell as far as I'm concerned.

Thank you, sir.

Thank you sir

Hey racer chris... sounds like innovate sold you on a plug and pray setup ... sucks. all my experience with innovate products has been so so.

I have an lc-1 and have used lm-1's at the ducati shop on the dyno.

My 2 cents is that those tail sniffers are junk.. They always fall out and screw shit up. If customer's or even buddies are wanting to finer tune these cars you should line up some welding and put bungs in place. this will help you better tune also as the mixture reading will be closer to the head and not mixed together with some excess air at the tail pipe.

Also that signal conditioner circuit idea should work but the circuit most likely wasn't designed well enough. I bet one of the vr sensor conditioners circuits on my megasquirt 2 could give a good solid pulse signal to the lm-2

Here's what I have:
1911 cc with 8.6:1 compression
Webcam #86 with Bursch exhaust
ACN SVDA with vacuum connected below throttle plates. Timing set at 27 BTDC at 3500 rpm (vacuum disconnected)
IDF40s with 32mm chokes, 135M, F11, 210A, 50I
AF at idle is 12.5.
When I accelerate easy in 1st gear it goes way lean...like 16-19+ and hesitates. Pretty much does the same in all gears, at steady state and 2500 rpm AF is 13.5 but giving a little throttle the AF jumps up to 16+ and it hesitates. Same at 3500 rpm. At 4500 rpm steady state the AF is 15.5. I will drive it more over the next couple days and take better notes. Sorry for not having better data but I had to rush home to meet a realtor...3 hours later my head hurts and I'm trying to remember AF data .

sounds like your idles are real close. and your mains are too lean. you should install the biggest mains you have, so you know when they tip in. it will be obvious. when you go thru your progressive circuit, it will get leaner and leaner till your mains come in then it will swing way rich. since your idles are so close, i have 50's in my 1.8 also. you need to work on your air corrector jets. i like to call these timing jets. your hesitation is caused by too small of an air corrector. the air corrector jet determines when your mains tip in. bigger air jet brings the mains on sooner. smaller airs bring them in later. that is the reason to start with huge mains. so you can see exactly when they come in. then you gradually go bigger on your airs untill the hesitation is gone. then jet your mains. then your done. you want your WOT a/f to be 12.5 - 13.2

I'll get new mains tomorrow because the 135s installed are the biggest I have. Do you think 145s are big enough? Regarding the air corrector jets, I have 210s installed and the biggest I see listed is 220. Is there anything besides larger air corrector jets that will bring the mains in sooner?

PLX Controller Unit

http://www.youtube.com/watch?v=xTRKGP9N1PY...re=channel_page

lets work one problem at a time....what is your wide open throttle readings now? find a long gradual incline and do some 3rd and 4th gear WOT pulls. are your plugs new? valves adjusted? carbs synced? air filters clean? do you run premium fuel?

i forgot........one very important thing. you need to disable you accelerator pump squirters. i just pull the little cotter pin thing and let the arm fall. when your done with the jetting we will hook them back up. you may find you only need a little squirt from them. but you have to disable them cuz they will throw of your readings.

do you have a jet reamer and jet gauges. they may save you alot of money in jets. my jetting is 50 idles, 300 air (no jet installed) and 185 mains. the wide band doesnt lie. i know my jetting is crazy. but i have zero hesitation. smooth transition, and get 40 mpg. and pulls like a freight train.

That is very interesting Doug!

This is what I've bought via Richard Clewett @http://www.clewett.com

I'm very happy with it.

Just buttoned up the car to take for a drive to get WOT readings.

The top of the velocity stacks are only 1/2" from the top air cleaner cover. Is this right? Seems there isn't a lot of room for the air??

Plugs, valve adjustment, air cleaners were all serviced/replaced about 500 miles ago. Just installed the cable sync linkage from Tangerine...carbs are sync'ed. I'll post AF numbers in a while. Thanks.

Yep, me too.

I found #1 idle jet was plugged so I cleaned that out and readjusted the idle mixtures/sync. AF at 900 rpm idle is 12.5. WOT in 4th gear starts at 11.0 at 2000 rpm (maybe influenced by accel pump), at 3000 its 12.5, 4000 is 12.5-13, 5000 to redline is 13.5-14.0. Steady state 3rd gear I can see the AF jump from 12.5 to 13.5-14.0 when I ease it up from 3000 to 3200 rpm so I think that it when the mains kick in. It runs strong, only issue now is slight hesitation off idle. Next time I'll disconnect the accel pump. Feeling much better now with the way it's running.

good progress....the best way to tell when your mains kick in is to pull your whole main stacks OUT. and drive your car around on just your idle jets......you will get a good feel for the tip in. you'll be surprised how well you can do with just your idles.....just dont try to climb any hills . these carburators operate on throttle position and vacuum. i know since we dont have tps's all we have to go by is rpm. but rpm really isnt a good reference. thats why i suggest pulling your main stacks and driving around town. drive alot. all day. so you know what your throttle position is at tip in.....

you deffinatly need to disable the squirters. its throwing off your readings....try again and post back.... your getting close. p.s. im using cb performance idle jet doctors and havnt had a plugged jet since.....i also run uni foam prefilters on my carbs. i still have that offroad mentality .

chris.....what is interesting? my jetting? or my jetting technique?

Will disconnect squirters and take more readings. With the main stacks removed, how will I know when the mains kick in? Also, do you think it's an issue of only 1/2" gap between the velocity stack and air filter? That's the ways it's always been but it doesn't seem right. Do most setups run the velocity stacks?

Yes.

With the squirters disconnected I got basically the same AF readings. WOT in 4th gear AF is 11.0 at 2500, 11.8-12.2 at 3500, 12-12.5 from 4500 to redline. Except for more hesitation it drove the same as far as I could tell. I'm tempted to try with velocity stacks removed to see if that makes a difference. Thoughts? Thanks.

You can lean out the idle mixture a bit more by opening the air bleed screws just a little further. That won't affect the mixture once the butterflies start to open.

At 2000 rpm the main jets are not a major factor.

I don't think the v-stacks being close to the air cleaner tops has anything to do with your hesitation.

the 1/2 inch may or may not be a problem....i run velocity stacks but it seems like i have more room than that. its raining right now or i would run out and check. post up some pictures of your setup. you could find out pretty easy while your out testing......make a pass with your tops on than make another pass with them off. and see if things changed. and report your findings.

you will know right away when your mains tip in.....the car will fall flat on its face. this step will teach you how to feel the progressin circuit. it is very important. soon you will be a weber master. thats why we are starting from square one. idles........disable you squirters, remove your main stacks, reset your mixture screws (lean drop) then drive it around. you will find out how the idle circuit works and when it stops working. and that will depend on your throttle position and vacuum. the farther you open the throttle the higher the vacuum, your idles will gradually become overwhelmed (leaner and leaner) youll see it on the gauge. thats when your mains will take over. but not yours cuz your mains will be on your work bench

the idle and progressive circuit are handled by the same jet in the IDF carb.

dont wory about your off idle hesitation right now. we'll fix that after your jetting is done. that will be solved when you recconnect your squirters.

Here's a picture of my carb setup. The stacks are 2.5" tall and air cleaner is 3.125" tall. The picture make it look like there is more space then there really is.

did you try it with and without the carb top? did it make any difference?

I removed the velocity stacks and could not tell the difference. I've left them off for now. Today I removed the main jet stacks and drove around. It ran OK if I took it easy up to about 3k rpm then it died. Anytime I put my foot into it it died. AF was around 12.1 at steady state and 1500 rpm. I was running .50 idles so I installed a set of .45s and it still ran good but the AF was 13.5 at 1500 rpm. I think the .45s are good at least for now. Comments? I reinstalled the jet stacks and there was a wide band that hesitated and went lean, AFs at 18-20+. I installed 1.50 mains and it runs strong and most of the hesitation is gone. AF is around 13.0 when easing the throttle wide open in 3rd gear. If I mash it down the AF drops to 10-11 and stays there. I'm not sure what to do from here. So currently I'm running 32mm vent; .45I/150M/2.35A. The accel pumps are reconnected.

so now that you know what its like driving on the progression circuit (no jet stacks) is your hesitation at the end of the progression? befor the mains tip in? if so, open your air jet one more step. if your hesitation is off idle ore when the accelerater is depressed from a steady state, add a turn or two to your squirters. your almost there.....

.45's are awesome for your idles..... you should get really good gas milage during cruise. then should really come alive when you step on it...