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MG Midget and Sprite Technical - Anyone used a wideband Lambda reader?NMC

I was looking at one for tuning the aeroplane engine since there aren't any rolling roads that can reach above 3000 feet. I used a narrowband in the midget a while back but it was night on useless beyond pointing out the obvious.
Has anyone got some practical experience or know someone I can phone for some impartial advice on the useability of these gadgets?
Thanks
rob multi-sheds thomas

Yep - Innovate motorsport are the people that I use.

http://www.innovatemotorsports.com/products/MTS.php


Dammed good on my engine and I know a lot of other people who have used them on custom builds...
Toby Anscombe

I have the Innovate one too! :o)

Used it for tuning my EFi and it has done the job faultlessly.

Innovate give you a data cable and some software for detailed logging too which is all very useful for interpreting the results later.

The Lambda kit with sensor is around £150 IIRC.
Bob T

Okey dokey.
Now, if I wanted to find out how far out my needle is with a Stromberg CD150 (SU HS4 clone), would I use a wideband? I have a narrowband kit from Lumenition which ranged between too lean and too rich without stopping in the centre for more than 1/2 second.
I need to run the engine and have a crack at choosing a needle for it. The original was fine but it now runs variable timing (3 ATDC to 28 BTDC) instead of a fixed 28 degrees.

Can they really give an accurate figure from which you can plot your needle requirements?

When you run your engine, what does it show? Are you really after 14.7 at all times or does an engine ACTUALLY need to go RICH during the accel phase or does a pump jet merely add fuel to counteract leanneess during fuel inertia (if you see what I mean)

Not much info on the net that I can find and even some dealers I have spoken to seem to be unsure of what snake oil can do. One dealer didn't even know what stoichiometric (sp?) meant!!

Anyone want a day out in south Wales running an aeroplane in the driveway of a quiet suburban cul-de-sac? Bring yer Lambda reader an' I'll supply the beers!

rob multi-sheds thomas

Hi Rob

We just bought an LM2 to move into the 20th century :)

A friend has an LM1 on his Healey, he is experimenting with putting a groove in the needle to encourage the LM1 to show a 'spike' so he knows exactly where to mod his needles.

We ran an MX5 up with an LM1...very responsive. The LM2 has a 1gb sd card and cam record 40 mins of info. one can also buy an rpm pickup to correlate all the info.



Peter
peter burgess

Peter. Similar issue here since the carb is tucked away between the bulkhead and the block. I was thinking of a fine rode glued onto the damper piston a nd a small drilling in the screwed cap so that I can measure the height. I still need to get a better understanding of my 'target' lambda ratios since I've not found any written material telling me if I should be always aiming for just-rich-of-14.7 or whether the ratio should rise under accel. The narrowband showed a lean drop when the throttle was closed and a constant lean at idle (480 rpm. Not bad for a VW beetle engine!) which MAY be due to the piston bottoming out and restricting fuel flow out of the jet. I have a basic understanding of how to affect the readings such as putting a file to the needle, changing damper oil viscosity or changing weber jets but not of what lambda readings I should aim for.

Would any of you guys be willing to take a phone call from me on the subject?

tessa.thomas@tesco.net
rob multi-sheds thomas

Rob, you have mail.
Bob T

Thanks, Bob.

I'm on nights, so I'll call at the middle of next week after the misery ends, if that's OK.

Cheers.
rob multi-sheds thomas

I went through the same insane search with a narrow band sensor in order to find an acceptable needle for an SU conversion (TR6). I mounted a digital camera near one carb which had a graduated stick in the piston rod (like the one used in Hamill's book). The camera was operated by a bicycle cable. The object of this was to determine what station of the needle was involved at a specific rpm with the engine under load and correlate it with the AF meter reading. A wide band sensor might provide more useful info, as the narrow one read all over the scale.
Also, the info I have (don't remember the source) shows that an AF ratio of about 12.5 produces max power and 15.3 gives max economy, so for a street engine, a constant 14.7 shouldn't be the goal.
Berry Price
BTP Price

This thread was discussed between 19/08/2008 and 23/08/2008

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.