Mikes 1987 Chevy Camaro - Comments thread

Post your project vehicles here! One thread per vehicle please.
User avatar
Fred
Moderator
Posts: 15431
Joined: Tue Jan 15, 2008 2:31 pm
Location: Home sweet home!
Contact:

Re: Mikes 1987 Chevy Camaro - Comments thread

Post by Fred »

Peter wrote:Your XOR gate's current rating is 24mA, and the copy of Ravage that I'm using has XOR gates rated at 32mA.
Non-issue. Under 20mA is less than ideal, but only if driving something external. If driving something internal, eg FET-drivers, then 5mA is enough.
Also the cost difference for 1% tolerance resistors is pretty small so I always try to order them if I'm buying resistors from somewhere that has 1% resistors. This is far more important for the analog signal conditioning circuits.
+1 also, thermistor bias and battery divider network resistors should be tighter tolerance (0.1%). You can tune out the BRV easily, and you can generate a matching curve to the bias resistor, but that's less straight forward once installed/setup.
I'd recommend a better heat rating on your capacitors like x7r
It's more about tolerance than heat rating, but yes, +1
I don't know much of anything about diodes so somebody else should review them, but the current rating looks a little high to me. I think that generally results in a higher current leakage, and a higher price tag for no reason.
I didn't look, but they need to drop 0.3V or less at 20mA or more at all temperatures you expect to operate at. If not, they're not going to do much good. Diodes like this are fairly hard to find.
I assume that's the sensor that the Jaguar uses. If your board has no plans of ever seeing a boosted engine that sensor should give you a finer pressure resolution, but I like Ravage's sensor better MPXH6250AC6U ~3-36psi I think. More of a personal choice.
It's really more of a "what will i install THIS hw on" choice. You should use the narrowest sensor range you can for best resolution.
No, I don't think 500mA will do it. My original board had a 1A LDO reg on it, and the heat sink got too hot for my taste. My latest board has 2A of capacity, and bigger heat sinks.
Holy jesus batman. 500mA should be plenty for most setups. Do a current audit. Heat wise, it comes down to heatsink, v drop and current drawn, obviously. The regulator doesn't really have a choice. Descent heat sinking is essential, but one regulator to power map, cpu, xor, thermistors, tps, signal conditioning ics, should be plenty.
The first thing that I notice that I don't like about it is that it has about 20 times more resistance.
+1, it was crap. Aim for sub 100milliohms accept some error over it if you must.
Optoisolated digital inputs for... knock input?

I'm not sure where you got this idea. I think an opto in the knock sensor circuit would effectively block the frequency spectrum that you're trying to analyze with the knock sensor chip.
opto digital ins are a nice idea for stuff like clutch switch or similar. Not useful outside of that, though, as far as I can tell. LOL @ using one on the knock chip :-) No, it's an analogue input, and needs to be what it is.
Digital Outputs (relay controls) for fuel pump, cooling fan, torque converter lockup, anything else?
What's a "torque converter" :-/
IAT - I can wire this to a switch for cold starting, but eventually I want the ecu to run it.
I guarantee you that Fred won't like this plan.
Fred doesn't even understand this plan :-o Ignorant people don't like things that they don't understand, thus I don't like it :-)
I'll switch over to 1% for all the resistors.
Cept the thermistor bias ones, which, at least, should be better.
Also, the inside of my old ECU never got above 50c even on a hot day, but it wouldn't hurt to overrate the caps.
It's about tolerance, not failure.
yeah I need two inputs, ambient and intake.
Not really, one is enough for most people. If you live next to a mountain and like to drive up it from the beach, yes.
I double checked, you're right they won't work. The resistance isn't the problem, the 1.4V drop across the source/drain is, so I'll spec a different one out :)
If it was a FET, then it's got an RDSOn, not a V drop. If it was a BJT or IGBT, then it has a V drop, not an RDSOn. The above is confusing. The resistance was terrible, though :-(
I think Fred has some plans/ideas on using PWM on fuel pumps, and cooling fans.
That scares me. I don't know why. Probably ignorance.
Think 1000hp 2 litre engine with 1000hp of fuel being furiously pumped around at idle, it's shit. They draw 30A and it goes no where. Cooling fan wise, there are many reasons, such as noise, and power drain and consistency of temperature, etc.
A VR sensor probably isn't going to like the distributor's tooth shape. Why do you want a sensor on the distributor?
My distributor has a VR sensor in it, I'm not adding it.
I have something that you might like, coming soon.
I guarantee you that Fred won't like this plan.
That I want to control it with a switch until he gets support in the ECU?
Now I'm even more confused! :-/

Fred.
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!
malcom2073
LQFP112 - Up with the play
Posts: 211
Joined: Tue May 01, 2012 4:17 pm
Location: Shrewsbury PA
Contact:

Re: Mikes 1987 Chevy Camaro - Comments thread

Post by malcom2073 »

Yikes!! I needed to update this, sorry!

A lot of your comments (Fred/Peter) are non issues, since I'm using Jaguar's BOM now, so I'll skip quoting those.
Fred wrote:Holy jesus batman. 500mA should be plenty for most setups. Do a current audit. Heat wise, it comes down to heatsink, v drop and current drawn, obviously. The regulator doesn't really have a choice. Descent heat sinking is essential, but one regulator to power map, cpu, xor, thermistors, tps, signal conditioning ics, should be plenty.
Do you believe the onboard 500mA TA card regulator would be ok with a proper heat sink?
opto digital ins are a nice idea for stuff like clutch switch or similar. Not useful outside of that, though, as far as I can tell. LOL @ using one on the knock chip :-) No, it's an analogue input, and needs to be what it is.

My knock sensor goes through a knock module, and outputs a 5v digital On/Off signal indicating knock. Should be much easier to integrate than origonally anticipated.
What's a "torque converter" :-/
F.U. That's what :)
Fred doesn't even understand this plan :-o Ignorant people don't like things that they don't understand, thus I don't like it :-)
Sorry I meant IAC, for Intake Air Control.
Cept the thermistor bias ones, which, at least, should be better.
Thermistor being the coolant sensor?
It's about tolerance, not failure.
Understood. Measure twice cut once.
yeah I need two inputs, ambient and intake.
Not really, one is enough for most people. If you live next to a mountain and like to drive up it from the beach, yes.
1500ft elevation difference is about all the change I'll ever see. I have one sensor. I'll add another later if neccesary.
Think 1000hp 2 litre engine with 1000hp of fuel being furiously pumped around at idle, it's shit. They draw 30A and it goes no where. Cooling fan wise, there are many reasons, such as noise, and power drain and consistency of temperature, etc.
Ignorance, that's why it scares me. I'll take your word for it being ok.
My distributor has a VR sensor in it, I'm not adding it.
I have something that you might like, coming soon.
Oooo. I like you.
User avatar
Fred
Moderator
Posts: 15431
Joined: Tue Jan 15, 2008 2:31 pm
Location: Home sweet home!
Contact:

Re: Mikes 1987 Chevy Camaro - Comments thread

Post by Fred »

malcom2073 wrote:Do you believe the onboard 500mA TA card regulator would be ok with a proper heat sink?
Yes, almost certainly. You can't give it a suitable heat sink in the stock location, though. You could de-solder it carefully and reuse the part :-)
My knock sensor goes through a knock module, and outputs a 5v digital On/Off signal indicating knock. Should be much easier to integrate than origonally anticipated.
Easy, yes, but not very useful, no.
F.U. That's what :)
:-p
IAT - I can wire this to a switch for cold starting, but eventually I want the ecu to run it.
Fred doesn't even understand this plan :-o Ignorant people don't like things that they don't understand, thus I don't like it :-)
Sorry I meant IAC, for Intake Air Control.
I'm not sure how you can hook a stepper motor up to a switch, but if you know a way, OK! :-p
Cept the thermistor bias ones, which, at least, should be better.
Thermistor being the coolant sensor?
Yes, and air temp. BRV dividers are handy to have closer too. All can be software calibrated, but that's only applicable to DIY people like you.
It's about tolerance, not failure.
Understood. Measure twice cut once.
I mean, caps are wide tolerance parts, even the good ones. The bad ones are very wide, so your filter could be miles away from where you want it, at all temperatures, even 20C.

Fred.
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!
Post Reply