34:1 Afr?!

[maddog]

Changed the injectors to from Bosch EV1 (design 2) to Bosch EV6 (design 3). Another large difference on the fringes of lean burn.

The EV6 design injectors are better atomising injectors and it certainly helps with running more leaner mixtures before lean misfire, helps idle quality heaps, drivability from cold start and smoother driving.

Coupled with the higher coil voltage has certainly been a huge improvement (for me) I didn't really expect.

[Pinhead]

How about mileage? Are you giong to get a wideband sensor that can see how far you're going? EGT's?

Instead of spending $200+ for a used MSD booster or $150 plus for an off brand, I'm going to build one.

Power supply : High power supply regulater 0-30V 20A by LM338

[maddog]

Tell us how you go with that power supply. Its looks good. How hard is it to put together, does it come with a preprinted board or do you have to make this yourself.

Mileage, havent checked it out but the stock factory tune gave me around 400-450km a tank on a set route. With programable EMS and tuning around the 15 to 15.5:1 A/F ratio gave me a solid 600km per tank on the same route. With the new injectors and coil voltage I see an easy 50km extra on that route but need to check. For me its not just economy, its the improved drivability,idle and tunabiliy. The tuning window has opened up heaps and made it so much easier to tune. Cold starts are so much better (minimal temp compensation as compared to previously), the car is alot better to drive.

Re: wideband, I have a Innovate LC-1 I bought a couple of years ago but couldnt get to work on my EMS8860 at the time. Once I get this working I will be able to measure 22:1 on my laptop

Other things I am going to do are heating the fuel via coolant and making up a good oil/air seperator for the crankcase vapours to pass thru before going back into the intake. Neither are going to increase economy on its own but with tuning will allow me to push this lean burn to the limit. This engine I am experimenting on has done 330000km and has a bit of blowby and oil in the throttle body so a well built oil/air seperater (not just a can) will help.

[crazyman]

A thought just occurred to me while on the can. While that may be TMI, will this work for a cheap way to boost voltage to the coil?



I have an old one at the house somewhere, it's a 20 volt 1 Farad capacitor. IIRC, the thing keeps storing until it reaches it's limit, around 20v, even from a 12v battery. Just hook it up like this.

Bat to cap, cap to relay, relay to positive side of coil. Use the original coil positive to switch the relay on and off so the engine shuts off when you want it to.


EDIT:::: I learned something. They only charge to whatever voltage you give them. 20v is it's max rating.
It would however provide a beautiful, rock solid, DC voltage to the coil.

[MAP]

Hi,

Q = CV, so i = dQ/dt = i = C dv/dt. The capacitance is just a way to store energy in the electric field set-up between the capacitor plates. When the instantaneous power load is high, a capacitor's main utility is to minimize the drop in supply voltage. That's if it's used as a supply rail voltage "stiffener," as they say in EE parlance. To use a crude analogy, a capacitor is like a WC tank. Energy derived from water-line pressure slowly fills the tank, but the moment you flush the WC, it's the gravitational potential energy of the water in the tank that provides the big "oomph" to get a first-rate flush.

But going back over the past several posts - it seems like quite a few of you are doing a lot to further the state of the art here (at least at the aftermarket level - Lean Burn, OTOH, is carrying the torch forward at the OEM level.) I can't wait to see the developments that get posted here!

Best,
Mark

[MAP]

Greetings again,

If I were in the aftermarket automotive business (let alone the OEM,) I'd look at today's oil situation as a golden business opportunity: develop EFI kits for popular motors with wideband O2 sensors, with wideband duty-cycle injectors, or perhaps pairs of injectors per cylinder, coupled with the kind of ignition characteristics needed to support very lean AFR's at light load. Non-emissions applications only, of course, due to NOx.

With the price of gas nowadays, and for people who would drive their "hobby" cars daily, the amortization rate could justify a system costing thousands of dollars at the retail end of things. Who would have believed it just a few short years ago?

Or, if I were a carburetor manufacturer, I'd concentrate R&D resources to maximize very light-throttle performance, in addition to the WOT aspect that the aftermarket has focused on since nearly time immemorial. Can you imagine the advertising mileage that could be gleaned from claiming a design that excels in both aspects?

To the movers and shakers out there (and I know at least a few of you are lurking who haven't posted,) hint, hint!

Best,
Mark

[Pinhead]

Originally Posted by maddog

Tell us how you go with that power supply. Its looks good. How hard is it to put together, does it come with a preprinted board or do you have to make this yourself.

I have to put everything together from scratch. I picked up the main components yesterday, but since I'm such a tightwad it's going to take a little while to find the heatsinks, casing, etc. for cheap (hopefully free ).

[howieschoon]

Hello all,
This may be a stupid question to some but I know that people have talked about burning valves, etc. when running even slightly lean AFR. Is this only a problem under full throttle (high loads) because then the engine is making more or less as much heat as it can and it has trouble getting rid of some of that heat fast enough? I really should know this but am somewhat ashamed to admit that I do not know it for sure. The idea with lean AFRs is to keep dynamic compression high (and therefore efficiency) at part throttle, light loads, correct? So when the load starts to get higher the AFR would go closer to stoich, much like a diesel. I do hope that I am right in these respects, or I am going to feel really dumb
Thanks,
Howard

[Brian P]

That's pretty much the way it is. You're not going to burn an exhaust valve at 10% load (or whatever).