can I hire somebody here?

[Roff]

LM324 is a quad op amp, which is good, because he needs more than two.

 

[shortbus=]

Like TCMTECH has said, what you are after doesn't make sense! You have changed your mind a couple of times!

"The circuit needs to use the tach wire from a GM HEI module
measure the rate change of the frequency, if the rate change is too great it needs to output a ground signal so I can trip a light or buzzer....."

"They did have something close, a "frequency switch" but it only worked by tripping with a set frequency range, where as i need something that trips with a change in frequency rate.... make sense?"

"on each acceleration i need a circuit that checks and makes sure the engine is not accelerating too fast, I would like this to be simple without using PIC programming "

"at ANY time over 2000 rpm & has a trigger rate greater than X it should fire (tripping the relay), as soon as the rate is decreased below X threshold it should reset (releasing the relay).
It should work at a minimum of every 1/2 a second, the faster the better, (down to about 1/5 of a second maybe.)

HOW IS THIS "CIRCUIT"SUPPOSED TO MEASURE RATE OF CHANGE WITHOUT A "CLOCK" TO MEASURE AGAINST? (PIC)

HOW LONG DOES YOUR MOTOR TAKE TO REV FROM 2000 RPM TO MAXIMUM RPM? YOU ONLY WANT THE RELAY ON DURING THE TIME OF CHANGE? WHAT "TRIGGER RATE" ARE YOU TALKING ABOUT? THE TACH SIGNAL IS THE ONLY "TRIGGER RATE" YOU WILL GET FROM IT!

IF YOU ONLY WANT THE RELAY ON WHEN THE MOTOR IS CHANGING FROM 2000 RPM TO MAX RPM, THE RELAY WILL ONLY BE ON FOR A VERY SHORT TIME, ON A GOOD RUNNING ENGINE POSSIBLY LESS THAN A SECOND!




"I would also like to have it control a relay for a secondary fuel system...."

"it needs to click a small relay, something around the size of an axillary fuel pump relay"

"i had a Holley double pumper on it but I have a goal of 20 MPG...."

HOW WILL ADDING EXTRA FUEL HELP YOU TO GET YOUR 20MPG? IF YOU CAN'T GET 20 MPG WITH A SBC YOUR NOT MUCH OF A ENGINE BUILDER!

The guy's on this site are real smart and could/would help you to do what you want, but you have to be HONEST with them and tell what you are really after. Instead of wasting their time trying to do something and not knowing what you want.

A micro-switch on the throttle linkage of the carb would probably do what your after. Or a vacuum switch in the manifold. Or a tach with a shift light set for what ever RPM you want your relay to turn on at.

 

[tcmtech]

Here is the correct circuit for the 700R4 torque converter lockup. Bowtie Overdrives
It is quite simple being the transmission itself still does all of the actual desision makeing as to when it needs to be done.

I had a chat with a few of my Professional gear head buddies and they had no rational reasoning to how the circuit as you proposed it to work would benefit anything or even be useful.

Having the torque converter lock up other than when the transmission itself dictates it will eventually damage the torque converter clutch and torque converter and the transmission.

Having to turn on a second fuel pump for that size of engine makes no sense either.
If your fuel pump is working properly you would never need a second one to turn on during acceleration. The low budget electronic diaphragm ones will still feed well over 500 HP and so will the tank mounted electric units and the old engine mounted mechanical ones as well. So that application is highly doubtful as well.

Shutting off the fuel pump on a carburetter engine wont work as a rev limiter but will create a very lean burn condition that can burn valves and melt pistons when the carburetors internal fuel reserve drops below a point where the jets and metering system start sucking air and fuel vapor. This causes extremely erratic combustion and often detonation in the engine that will eventually cause catastrophic damage to the pistons and main bearings and can even break connecting rods as well.
Provided the fuel in the carburetor didn't some how already supply enough energy for the engine to have already flown apart.

According to them the aftermarket electronic ignition systems with built in rev limiting do not turn off the ignition but instead they greatly retard the spark and many now skip fire the cylinders so that they dont have cylinder wall wash down issues. The full turn ignition turn off design hasn't been made or put into practical aplication for over 20 years.

Their other theory was that its not nitrous related either. Turning on nitrous is done differently and under far different engine operation conditions according to them.

Overall their conclusions where that whenever someone cant find a aftermarket product that can do what they think they need done they usually dont have any solid of understanding of how things work. And when that person wont explain what they are trying to do and why it likely because they dont know what they are doing.

Auto tech guys by nature love to talk theory and application stuff. The ones who are secretive about why they want some mystery device usually want it because they dont know what they are doing or talking about or are working with well debunked or misguided fuel saving concepts like the HHO and similar para science voodoo.

I work with alternative fuels and I have ran some crazy ideas past them before about how to modify factory and aftermarket equipment parts well beyond normal and convectional applications and they have always been more than willing to help theorize me through to a working end concept.
In gear head land there is no conceptual theory that cant be taken apart and reworked into the correct end result if the person who has the idea is willing to listen and learn.
But they always need to know what intended end result is first whether its practical or not.

 

[HarveyH42]

Is the secondary fuel source, HHO? Maybe I missed it, didn't exactly read every post. Just curious, it was kind of tough trying to visualize just what it is you are trying to accomplish. Usually better to give complete and accurate description of what you need help with. A lot of bright people here, who tend to lose interest after a while, if they have to guess a lot. If you want a trained engineer, you have to present your problem on their terms. Usually get out, what you put in...

 

[joe_rocket]

I have said pretty plainly what I want. I have not said exactly what I want it for b/c it's a secret.
That much is pretty simple.

I want or need a circuit that will be adjustable.
I need it to be able to trip a light or relay if the triggers acceleration rate from the tach wire on a GM HEI module is greater than X.

It would be best IF it was adjustable in the trigger rate and the length of time it was "active" after tripping.


I have shown you my car and a video of it running. You know what I'm working on, you know what I want, and I even offered to pay.

I do not need what is on the market today, unless this product is available somewhere.

I have looked at the diagrams that Mbarazeen posted.
Looking at it i think the Differentiator checks for a change in voltage, and I have made one in yenka that appears to work.
I also made the negative voltage generator, and it also appears to work.
The last circuit. the frequency to voltage converter I cannot build but I have found other online and it appears to be scanned from a text book or the like and I will assume it will work. The last I said I was going to town to buy the parts, they are on order and I am waiting for them to arrive.

If somebody has some constructive comments in regards to the divice and it's operation please feel free to comment. IF you are only going to suggest off the shelf items or speculate about its intended use please don't. I came here for help, if you are not willing to help please don't dilute the thread with useless posts.

-Thanks

-ps-
I would also liek to say thanks to Mbarazeen and Roff for their helpful comments and suggestions.. Thanks guys!

 

[Roff]

I could simulate the entire circuit in LTspice, but that wouldn't allow you to play with it.
One tricky part is the 40106, which can be emulated with a couple of voltage-controlled switches.
The other somewhat tricky part is the accelerating input signal, which can be done in LTspice with a modulator. I don't know how to do either of them in Yenka.

 

[shortbus=]

"I want or need a circuit that will be adjustable.
I need it to be able to trip a light or relay if the triggers acceleration rate from the tach wire on a GM HEI module is greater than X.

It would be best IF it was adjustable in the trigger rate and the length of time it was "active" after tripping." Quote, Joe Rocket


What you just described is a "Shift Light"

A distributor is a linear device. it only changes "trigger rate" as engine RPM increases. There are no other things to measure from it.

It also doesn't give negative/ground pulses. It grounds the positive from the coil to cause pulses in the coil. Get a book on ignition systems.

 

[Roff]

"I want or need a circuit that will be adjustable.
I need it to be able to trip a light or relay if the triggers acceleration rate from the tach wire on a GM HEI module is greater than X.

It would be best IF it was adjustable in the trigger rate and the length of time it was "active" after tripping." Quote, Joe Rocket


What you just described is a "Shift Light"

A distributor is a linear device. it only changes "trigger rate" as engine RPM increases. There are no other things to measure from it.

It also doesn't give negative/ground pulses. It grounds the positive from the coil to cause pulses in the coil. Get a book on ignition systems.

A shift light is activated at a certain RPM. He wants a device that triggers when the rate of change of RPM (acceleration) is above a certain limit.

 

[joe_rocket]

Thanks Roff, that is exactly it
Tomorrow I'm going to check and see if the parts are in and (hopefully) start piecing it together.

 

[joe_rocket]

I have tried to build this in Yenka several different ways, for days now and i cannot get it working.

I had to find a schmitt trigger inverter circuit and build it and also build an op-amp from this diagram:
File:OpAmpTransistorLevel Colored Labeled.svg - Wikipedia, the free encyclopedia

right now I have a very large circuit and all I am seeing is it acts like a capacitor that takes a charge then looses that charge in the off cycle....
here is the yenka file:
**broken link removed**

image:
**broken link removed**

does anybody know if i made a mistake, if this circuit doesn't work or if it is yenka not working correctly? I have been on this for half the weekend and my eyes and head hurt

 

[Roff]

Your discrete op amp won't work. IC op amps have many subtle details that are not shown in the schematics, such as transistor geometry scaling. Yenka has a 741 op amp (old technology) and a 324 (should work for you). Your Schmitt trigger is a bipolar unit. You need a CMOS Schmitt. Actually, a Schmitt trigger is not even required. The key function of the Schmitt in the original circuit is to charge the capacitor on its output on one half cycle of the input, and transfer that charge to the capacitor in the integrator (the OP07) on the other half of the input cycle. A CMOS inverter would work just fine. You might be able to use the ZVP2106A and the ZVN3306A to make a workable CMOS inverter.
I hate to say this, but I think you're in over your head here. Yenka looks like a nice application (I believe the circuit simulator is Crocodile Clips), but you are the first person on this forum to mention it, AFAIK, so there are probably no experts here to help keep your head above water. You might find a Crocodile Clips user here.

 

[joe_rocket]

I probably am in over my head but I was able to learn enough so far I made a narrow band O2 sensor for my car which is much cheaper and I think will work much better than the off the shelf units that are just for pretty flashing light. I have only bench tested it so far but may install it today.
I actually designed 2 of them, only built one.
It works by turning on one green led that goes out and a bright red led goes on if the engine a/f ratio is lean. the off the shelf units have about ten lights that dance back and forth with rich being the brightest and no lights lit when lean. IMO it's better to see little or no light when fine and trigger a bright red warning light if something goes wrong. the second one I designed (but did not yet build) has one green led at WOT, if the engine is in stoich the green goes out, one yellow lights as it gets leaner the second yellow then finally the red.... if anybody wants I can share these super simple plans. (just uses a differentiator to switch between the two at 600mV) **broken link removed**

but i'm getting O/T, I figured this was over my head but i am willing to pay or hire somebody to build and explain it to me. not the circuit, I can put it together with the right plans..I think.

 

[Roff]

Doesn't the free version of yenka have an oscilloscope? I'm building your circuit, and I can't find one.

 

[joe_rocket]

not that I know of, I was just using the graph function...

**broken link removed**

 

[joe_rocket]

....edit.......

 

[Mr RB]

I thought they had been selling those for years...

 

[tcmtech]

If he would have just told us what he wanted weeks ago I could have told him exactly what he was looking for.

Good thing he kept it a secret and didn't end up coming off looking well...

 

[joe_rocket]

I think these just hit the market, there are none in **broken link removed** and I've been looking at HEI modules on ebay for a bit, that is how I found that $60 module for $5 plus shipping. If nothing else I've learned a lot about electronics from Roff and Mbarazeen and will at least double my money on the module if I don't use it

 

[tcmtech]

I thought they had been selling those for years...

My auto tech buddies seem to think the same thing. Best recollection they had is its late 90's tech.
Its probably been improved on in 10+ years but its certainly not new by any means acording to them.

 

[Sceadwian]

joe; Ebays closeout listing is a measure of nothing squared. It's still nothing.