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Tech Spam thread - because 1/4" BSP gets 5 hand spans to the jiggawatt


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Posted

theoretically yes. but when you are trying to tune it or diagnose an issue its golden. e.g. is it operating an an almost fully open position or almost full closed, what is the actual rate of change of opening and closing vs where the controller is asking it to go.

 

so yes you can operate/tune with just the process variable but its like driving with tunnel vision/ you have no idea you only just missed that logging truck by millimeters on that occasion.

 

not sure what the failure modes of the system are or safety concerns but if its an inlet or outlet fan but in a upset or trip condition you probably would like to know things are fully open or shut too and have some kind of interlock on startup too maybe.

 

 

Yeah fully agree, knowing the dampers are in the correct "home" position would be golden for troubleshooting, possibly even measure on the damper ring rather than the cylinder to get rid of any deadband / hysteresis.

 

Considering doing this even if we leave the control as it is to reduce troubleshoooting downtime and ability to interrogate trends more accurately.

 

such as trends:

 

 

Green line is the pressure trend (5 second value),white is inlet OP, yellow is exhaust OP (two fans and 2 dampers but one control output) pink is pressure SP.

 

 

there is some other junk on there like bearing temps etc.. but white yellow green and purple are the main players in the pressure system.

 

Scale on the left is -100mm wg to +100mm wg

 

This is a good start up pressure from the 13th

 

 

20150115_115244_zpsee2d26e9.jpg

 

 

this is yesterdays start with no adjustments made from previous day. the -ve trip point is -60mm wg and we got to -57.4mm wg to pretty close to a trip.

 

20150115_115320_zps99b7eded.jpg

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Posted

Is there a relationship between 'size' of cam and minimum idle speed? I am only part way through tuning my car but I have warm idle at just under 1000rpm which is pretty low I think, but as it is now, when I touch the throttle the engine stumbles, goes lean and takes a while to get out of the hole (relatively).

 

How can I tune to stop this happening or should I just increase the idle speed a bit as I am fighting a losing battle?

Give it more AE, I got rid of the hole on my slides with 25ms of AE hahaha

Posted

I increased idle screw a bit and it made it a lot better, idles at 1100 now.

In traffic it slowly gets up in temp, it did t used to do this with the carb setup, Sentra Dave mentioned timing might have something to do with it. I'm currently at 12 degrees btdc at idle. Which way should I move it? Sitting in the garage the temp stays ok just in heavy traffic in the sun today it was happening

Posted

12 sounds pretty sweet tbh. You could try backing it off to 10 and see what happens but if it ain't detonating I'd leave it as is and focus on a bigger rad or fan etc

Posted

yowser, every person on the internet says advance idle (to a point) for cooler engine not later and makes sense, why do you suggest later?

 

regarding 12 degrees, out of interest on ms are you reading that off the ignition main table position or the current/corrected true angle readout?

Posted

thats a true angle readout, I advanced it to 18, I will see what happens nect time I drive it

 

regarding a bigger fan, can someone find me one that is more than the 80w advertised on pretty much every trademe ad, I might be able to fit a 12 inch (10 in fits now but larger than original) and as thin as possible

 

my engine bay is super super hot and it would be great to get it down somehow, what are some tips? hot engine bay happens primarily at low speed/rpm

Posted

Even if a bit more advance does get it running a bit cooler your cooling system sounds like it only just up to the job on hot days in traffic when everything heat soaks to fuck.

 

Sucks you don't have much space, really need to get a fan that is OEM and make a shroud for it. The volvo/ford one is pretty much the gruntiest. Its what KK chucked on his commy, it has 2 stages and moves 1 million CFM. I can measure my spare if you want, but its massive compared to any of those shitty thin aftermarket things.

Posted

Been one-man tuning the TX3 the last couple of days, I know it's apples and oranges but I managed to get around feather throttle stumbles and momentary lean AFRs by dicking with the acceleration enrichment as mentioned.

 

Oh, again, apples vs oranges, but I increased my timing at idle from 12 deg to 19 deg BTDC and it actually made a difference in coolant temperature (hovers around the low 80s instead of closer to 90 deg now) which has been noticeable on a scorcher of a day like today was. Go figure...

Posted

thats good, I am getting it as good as possible with accel enrichment off, I dont think im doing too bad so far

 

my 3d maps on the other look like a mess haha, they are a rocky landscape thats for sure

Posted

Hey Peter when people fit an EGT (Exhaust Gas Temperature) sensor, they always find that when you run low ignition advance the EGTs go up.

 

As you advance the timing more the EGTs go down.

 

If your motor is running noticably hotter than when you had carbs it could be that the ignition needs to advance a bit more at low load / idle etc

Posted

Looking at a electronic ignition, pertronix to be exact. Have run one before in my old landcruiser and was good but have read a couple of reviews and they aren't so good.. any other recommendations?

Posted

Any one ever found a pull type clutch slave cylinder? Eg to replace a cable clutch?

Or do you think there's a market for it?

Cancel that, wilwood make one. I'm sure last time I googled it no one made them, but that was a few years ago. Iv just melted the like 10th clutch cable on escort so prob should upgrade

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