1987 voyager with displacement on demand...

[lookin]

Quote:

Originally Posted by c2xejk Having built one out of automotive grade components for some testing, I can definitively say it would _NOT_ cost $100.... Even in small quantity, the parts were more like $20-30... The op amp chip I used was smaller than a dime... Probably fit 2-4 on a dime... The resistors in series would only lower the sensed voltage which would make the ECU think the engine was slightly leaner. That would result in adding more fuel... That is the opposite of the goal in this case...

Hi. My name is Dyan. I am a Sr. Test Engineer at ITT Aerospace Communications. I have 40 years experience in electronics test and design. Natasha asked me to respond to you Ed.

Yes you can build an amplifier for about 20 to 30 dollars. But to build a quality instrumentation amplifier that is temperature compensated, EMI shielded, vibration and weather resistant, costs considerably more. You need a quality PCB, an instrumentation op amp, a high quality voltage regulator and EMI shielding, all in a hermetically sealed enclosure. What you made for testing purposes, is just that, for testing. In other words we are talking apples and oranges. In 1976 I designed an engine analyzer for Clayton Mfg. I learned a great deal about engine EMI and thermal problems, and I needed to change my design several times because of this. My first designs worked great, in the lab, or for a limited time when exposed to an actual running engine. So I understand what is required.

Dyan

[lekota]

Could one thread a 2nd o2 sensor into the end of the front manifold and wire it so that when you switch to the front cylinders, the ecu would read from that sensor. I imagine that would solve the a/f ratio on the front cylinders to some extent.

Obviously the rear cylinders would need a more complex solution (custom header or switches/resistors/other electronic components discussed above) due to the design.

[c2xejk]

I am still trying to find the schematic... That said, it was not that different from many that are in the part books... Pretty basic stuff used all the time in automotive controllers all the time. Many of these controllers are built and sold in bulk for $100-200/controller... (we even make some that sell for a lot less...)

As I said before, the guy that designed designs controllers for automotive use by a major automotive supplier. This circuit is very similar to the one that he would use in an automotive controller. They work down to -40C....

To seal it, put in a plastic case and RTV it. Mount it where water is less likely to get at it and you will be fine. As far as EMI, wasn't an issue in my testing, but my part was located in the passenger compartment so I could tweak an monitor it. That said, I didn't see any problems when I was monitoring it with my oscilloscope...

Simple voltage regulators are available at even places like Radio Shack for under $5... Likely that you could also use the +5v power supply that the sensors use...

Most of these parts now have temperature compensation built into them...

Though thinking about the circuit, it would likely need to be modified to amplify the signal. The circuit was originally designed to attenuate. If anybody has access to a parts book, you could find a design listed there that would work...

Quote:

Originally Posted by lookin Hi. My name is Dyan. I am a Sr. Test Engineer at ITT Aerospace Communications. I have 40 years experience in electronics test and design. Natasha asked me to respond to you Ed. Yes you can build an amplifier for about 20 to 30 dollars. But to build a quality instrumentation amplifier that is temperature compensated, EMI shielded, vibration and weather resistant, costs considerably more. You need a quality PCB, an instrumentation op amp, a high quality voltage regulator and EMI shielding, all in a hermetically sealed enclosure. What you made for testing purposes, is just that, for testing. In other words we are talking apples and oranges. In 1976 I designed an engine analyzer for Clayton Mfg. I learned a great deal about engine EMI and thermal problems, and I needed to change my design several times because of this. My first designs worked great, in the lab, or for a limited time when exposed to an actual running engine. So I understand what is required. Dyan

[sleeperspirit]

i went to school with a couple girls that plan to be Techs and i think its going to be tough to find a job cause of all this BS sexual harrassment crap. if anyones ever worked at a shop they all know what happends when a bunch of guys work together every day

[lookin]

never mind

[sgt. minivan]

it would be awsome if she could make me a board to control the 2 banks of cylinders.

[phantomrt]

Dudes, simply disconnecting fuel injectors and not doing anything else and getting better gas mileage is a total myth.

[Boogieman142]

that amp isn't that what an "EFIE" is the plans are 9.00 and the whole thing is 60.00 and the price goes down the more you buy....group buy maybee. I've got one on my sentra and it does work. their prices are

1-4 - $60.00
5-9 - $42.00
10-24 - $40.20
25+ - $39.00

Eagle-Research: Fuel Savers HydroCarbon Oxygenator EFIE

[Ondonti]

Quote:

Originally Posted by phantomrt Dudes, simply disconnecting fuel injectors and not doing anything else and getting better gas mileage is a total myth.

Mind explaining that?

[phantomrt]

As already mentioned, there will be clean oxygen getting pumped into the exhaust, and of course the oxygen sensor feedback will compensate with more fuel to the three cylinders still running. Thats one reason. Next reason is that since you're into the throttle more, there's less ignition advance. Gas mileage will slump. We can get in a huge debate on what cylinder combustion chamber pressures become--with more throttle, they'd increase in pressure/efficiency under certain circumstances, but as I said, this is well open for debate.

If there's any way in the world that this quick modification would result in better mileage, there is no way its going to go from 25 mpg to 30+ mpg by doing so.

Last of all, if doing such a simple modification will result in a NINE mile per gallon increase, even if it is JUST on the highway, the auto manufacturers would have absolutely NO trouble getting their corporate average fuel economy well above what the government requires, and it would cost them next to nothing to do it.

A 35 mpg purely gasoline powered minivan won't happen. Not like this.

[Ondonti]

I dont know. 200-300 rpms cruising speed difference in my spirit between the 3.5 and 3.77 trans makes a 5mpg difference. Difference shown over multiple 950+ mile trips.

[Boogieman142]

i get 35 give or take 5 depending on habits at the time with 3.85 gears, i actually gained a tad over the 604

[sgt. minivan]

Quote:

Originally Posted by phantomrt As already mentioned, there will be clean oxygen getting pumped into the exhaust, and of course the oxygen sensor feedback will compensate with more fuel to the three cylinders still running. Thats one reason. Next reason is that since you're into the throttle more, there's less ignition advance. Gas mileage will slump. We can get in a huge debate on what cylinder combustion chamber pressures become--with more throttle, they'd increase in pressure/efficiency under certain circumstances, but as I said, this is well open for debate. If there's any way in the world that this quick modification would result in better mileage, there is no way its going to go from 25 mpg to 30+ mpg by doing so. Last of all, if doing such a simple modification will result in a NINE mile per gallon increase, even if it is JUST on the highway, the auto manufacturers would have absolutely NO trouble getting their corporate average fuel economy well above what the government requires, and it would cost them next to nothing to do it. A 35 mpg purely gasoline powered minivan won't happen. Not like this.

Got one question for you.... have you ever tried this?? hmmm i didnt think so, so before you go basically calling me a lier, why dont you do it, i DID do it and it DOES work, ive already explaned that its not very practical, but does work under certian situations... i say yes you say no, i have done and proved yes to be yes, you have not, but still say no??? wtf??

[roguetrip]

This is interesting, I think looking into what chrysler did to the new hemi with being able to switch off 4 cylinders would give more insight to this.

With firing order 2-4-6 that would give quite a bit of rocking for each rotation and would wear the main bearings along with the rings out a bit faster by gasoline blow by from in enriched enviroment enticed with abnormal vibration.

Now if rocking and wear doesn't get ya, then a way to maybe eliminate the O2 putting the system into rich when the 1-3-5 cylinders are off, it wouldn't be cheap, but make a dual exhaust with dual O2 sensors, now the bank that gets turned of, also switch off the O2 sensor for that bank so it doesn't give a bad reading. Now all that air from the cylinders won't be interferring with the working cylinders and making the O2 run rich for the other pistons which would in turn wear rings faster and have to change oil more frequent due to blowby of gas into the system. I know lots of guys with thow flame thowers out of custom exhaust manifolds let the engine run very rich and cause those issues.

Also when running a dual exhaust on half the cylinders, i'd go for really small exhaust piping for better back pressure to keep RPM's up. 1 7/8's or less would probably be idea.

[Phatfoto]

I don't see how the ECM will be rich... Only three injectors are firing. As long as it is in closed loop mode, its reading the O2 sensor. It isn't until later generations that the ECM could detect misfires.

But yes, I do see where bearings would take a beating...