thegreatestben

Romans COD piece

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Mr RomanDave, if you ever feel like experimenting with cooling system wizardry, I have an electric water pump off a N52 Beamer engine for you

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I searched your thread, and couldn't find LiPo (or LiFePo). You mentioned wanting to drop the weight of the battery / cables, and you may like to look at those batteries. Even small ones have frightening output current capability, and you can get large capacity ones, though the $$ goes up. But, if you don't need lots of emergency reserve capacity the weight difference is Yuuge. I have one the size of two ciggy packets which''ll put out 3kW for 90s, at 20Volts.

(Disclaimer, the charge volts are different, and the cells need to be properly balanced, or they catch fire...)

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Thanks, yeah a light weight battery is something on the cards but I've not looked into options yet.

So thanks I'll check that out 

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On 7/30/2018 at 21:06, h4nd said:

I searched your thread, and couldn't find LiPo (or LiFePo). You mentioned wanting to drop the weight of the battery / cables, and you may like to look at those batteries. Even small ones have frightening output current capability, and you can get large capacity ones, though the $$ goes up. But, if you don't need lots of emergency reserve capacity the weight difference is Yuuge. I have one the size of two ciggy packets which''ll put out 3kW for 90s, at 20Volts.

(Disclaimer, the charge volts are different, and the cells need to be properly balanced, or they catch fire...)

I had a 3cell lipo which started my v8 coon with absolutely no problems (i used to use it as a jump pack)

Only thing that worried me was the small leads that came off it- short duration cranking is fine but for longer periods i'd be concerned.

Out of interest- what would you use as a BMS/charge controller in this situation? Aftermarket lipo car patteries (shorai or someone does them) have all of the lipo cells in a plastic box with built in BMS.

have also heard of folks using lipo cells with capacitor bank to supply enough crank current but that is a tad too complicated for me

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The long cranking would be a problem.

Initially I'm guessing a 4S lipo (14.8V nominal), because then you could use a standard alternator to charge (typically 13.8 to 14.5V). It won't fully charge the LiPo, but they don't sulphate and this will extend the working life. You'd need a cells balancer arrangement (available as a module, or in the plastic box per above). It'd probably be worth putting a relay on a thermo-switch on the battery, just as safety, (e.g. if battery starts overheating, disconnect the Alternator and starter relay circuits) (then car might continue to run on Alt).

(+BATT)---+---(Batt Temperature RELAY)---(Alternator and rest of Car, incl starter relay drive)

          |

            (Start RELAY)

      (Starter)

It'd need careful checking once built, to ensure safety, but should be good and light.

Also, LiPo needs to be rated for the Alt charge rate.

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oh man, Dave, damn!

That dash looks fucking COOOOOL

some shit yarns about conditioning signals :)

Averaging, or only displaying in increments of 100 doesnt make it flicker any less as you'll end up sitting at 2499-2501 and it will still flicker between 2400 and 2500 constantly. Better option is windowing your readings with hysteresis or just simply time based... like this?

#define RPM_HYSTERESIS        (25)
#define RPM_TIME_INTERVAL    (100)

uint16_t displayRPM;
uint32_t rpmTimeout, currentTime;

loop {
    currentTime = millis();
    
    if ((max(rpm, displayRPM) - min(rpm, displayRPM)) > RPM_HYSTERESIS) {
        rpmTimeout = currentTime;
        displayRPM = rpm;
    }
    
    if ((currentTime - rpmTimeout) >= RPM_TIME_INTERVAL) {
        rpmTimeout = currentTime;
        displayRPM = rpm;
    }
}

that way you get rapid change when accel/decel, and get real values displayed on the screen occasionally but not heaps?

if you wanna do rpm with blocks of 100rpm, use hysteresis to make it jump though like so;

uint16_t displayRPM;

#define RPM_BLOCK_SIZE    100
#define RPM_HYSTERESIS    ((RPM_BLOCK_SIZE / 4) * 3)

loop {
    while (rpm > (displayRPM + RPM_HYSTERESIS)) {
        displayRPM += RPM_BLOCK_SIZE;
    }
    while (rpm < (displayRPM - RPM_HYSTERESIS)) {
        displayRPM -= RPM_BLOCK_SIZE;
    }
}

theres faster ways to do that than use a while, but this way is easy to understand what it's doing.
you can also just repalce the while with is and replace displayRPM += RPM_BLOCK_SIZE with displayRPM = rpm.
It's faster and more efficient, but it wont display the nice round increments.
you can use that same system with all the numbers to stop them from flickering if you wanna update them in block sizes. Hope that helps?
You're fast getting into the rabbit hole of coding haha. This is where you find a whole new set of challenges :)

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Aahhhh thanks Ned! 

I had been considering some form of hysteresis however hadnt given thought as to how the code would work yet. 
So thought that just averaging or similar would be easier in the meantime.
But thats much more elegant than how I thought it would work and looks pretty easy to incorporate. Cheers! 

I'm busy working on some of the context based screens at the moment so cant wait to get these up and running!

Also cant help but get excited about adding new features and sensors etc and scope creeping it into oblivion haha. 
There is a ridiculous amount of cool stuff that you can do with a dash.

Like even just having a selectable diagnostics screen where it shows you all of the values from the engine/dash, current values and max/min. 
And having some basic XY plots of logged data that you can pull up. And having some conditional alerts/warnings. 
Save so much time troubleshooting things, or move away from needing to open the laptop for basic trackday checks. Thats the dream.

 

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no problem man, happy to help :)

and yeah, sooooo much shit you can do! lemme know if you get stuck or have any questions man :) 

Keen to see how it pans out etc! you going to put any real indication light on etc? like the blue high beam you legally need on your dash?

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Yes that all works, ive got 8 optos on a board bringing the needed dash plug stuff down to 3.3v 

If things arent on, they dont show up on the screen so it minimizes distraction. And I can have odo and trip meters etc too.

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Thanks. 

Looks like my wideband is starting to pack up, tuning from a fresh start is always hard on them. 
So no more ITB progress for a while, but so far it's looking like standard plenum might still be the winner by a smidge.

I dont want to make any sweeping statements just quite yet though.
As it might pull a few tricks out of the bag once the cam timing has been optimized.
Getting it right for the standard plenum makes a huge difference in airflow through the powerband, so I wont be surprised to see the same here.
It's a bit trickier doing this without a MAF but still doable.

I'm looking forward to seeing how different it might end up (or not) 

Excited to try some different runner lengths and different style bellmouths though!
 

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Map signal issue is usually at the other end of the scale.   will pull good vac at low throttle opening.     its up near wide open throttle that is the issue..  numbers depend on setup and revs, but  lets say 70% throttle; it will hit atmospheric pressure and flat line from there.   so yeh you're stuck with the same fueling numbers from 70% to 100% throttle.  so got to deal with  a rich spot or lean at wot

noise gets the approval though 

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Haha yes I see... 94 KPA at only 34% throttle hahaha. 

Needs a MAF :rolleyes::D

Untitled.png.bb7c20a9dbdac6ad1527f14e8d6fe67a.png

 

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18 hours ago, Truenotch said:

Can you fit 4 x mini maf sensors?

That would be really intetesting actually, or even per cyl map sensor that can see when the pressure waves peak relative to tdc... might give some clues to best cam angle when a maf isnt available.

Im hyped on some runner lenth experiments right now though! 17kw gain from runner lengthening is a crazy big improvement.

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Can you build a sweet carbon fibre air box and run a maf? Air box seems like the win on throttles anyway? Then run a proper outboard injector setup plz. Maybe some fancy/magic high pressure setup seems to be the good stuff.

Oh and I’m jelly of all your messing around with this car, A+ integration of cars/hobby/learning shit.

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