Author Topic: Vanbcguy's M-TDI Build  (Read 95260 times)

Reply #285April 29, 2015, 03:28:49 pm

RabbitJockey

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Re: Vanbcguy's M-TDI Build
« Reply #285 on: April 29, 2015, 03:28:49 pm »
Update...

Newer/better program on my VNT controller, has been working quite well.  Actually I'm finding that I was calling for TOO MUCH boost a lot of the time - backing it off a bit has made the car noticeably quicker, especially in the lower RPM ranges.  I attribute this to having the vanes open more which uncorks the engine quite noticeably.

i think thats really interesting, and i realize i am late to comment, but i know even some of my honda friends have said they found more power by opening the wastegate progressively with boost rather than holding it completely shut until max psi is achieved.  psi and spool up is not everything, its all about the flow, which is especially hard to measure on the exhaust,  except maybe with an emp gauge?
01 Jetta TDI 100% stock daily
81 Rabbit:TDI-M ported head, Frank06 cam, PD intake, hybrid T3 turbo, Renault intercooler, Syl20 11mm pump, light weight fw, and yellow California Clutch clutch kit

Reply #286April 29, 2015, 03:43:31 pm

vanbcguy

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Re: Vanbcguy's M-TDI Build
« Reply #286 on: April 29, 2015, 03:43:31 pm »
Yeah I actually do have everything to measure EMP which would make it a lot easier to tune intelligently but I haven't hooked up the sensor yet. Hehehe... The hose is even run and I have a block off plate on my exhaust manifold with a threaded plug just sitting there waiting. Lazy.

I've tried cycling the vanes from fully closed to fully open and back again while cruising along at light throttle. It makes a very definite difference, the flow through the engine is definitely needed. It's tempting to go all boost all the time but there really aren't any gains from doing so.
Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #287April 29, 2015, 07:48:49 pm

libbydiesel

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Re: Vanbcguy's M-TDI Build
« Reply #287 on: April 29, 2015, 07:48:49 pm »
On my mechanical control, if I am cruising and snap the pedal down, the vanes close until boost builds and the boost can opens them.  In that situation I can feel the engine brake effect of the vanes closing until the boost spikes up to max, the vanes open maintaining max boost and the clutch slips...   :P  It's not really an issue, though, as I typically drive more intelligently than that.  When someone controls a VNT with just a boost can, that engine brake situation occurs constantly unless at max boost. 

Reply #288April 30, 2015, 03:44:39 pm

vanbcguy

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Re: Vanbcguy's M-TDI Build
« Reply #288 on: April 30, 2015, 03:44:39 pm »
Interesting Andrew... Though I haven't specifically programmed anything in to my electronic controller to prevent that, the nature of PID control rolls the vanes closed "slowly" rather than going to fully closed right away, and rarely hits fully closed except when it's been trying for a couple seconds to build boost.  Fully closed will also happen when boost is less than 15 kPa in my case (I have an 'open loop' mode for < 15 kPa measured boost that closes the vanes fully before handing over control to the PID mode with a 'primed' integral value when boost passes 15 kPa)
Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #289May 01, 2015, 10:55:56 am

RabbitJockey

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Re: Vanbcguy's M-TDI Build
« Reply #289 on: May 01, 2015, 10:55:56 am »
yeah super interesting discussion haha, its against the norm of thinking about boost.  interesting too is that i've always thought, just use a boost can that's good enough haha.  i wonder if some it also has to do with compressor inefficiency at low rpms, like say trying to make 15psi below 2k requires way more energy (back pressure)to produce than what it adds.  i guess that is exactly what it is haha. 
01 Jetta TDI 100% stock daily
81 Rabbit:TDI-M ported head, Frank06 cam, PD intake, hybrid T3 turbo, Renault intercooler, Syl20 11mm pump, light weight fw, and yellow California Clutch clutch kit

Reply #290May 01, 2015, 03:15:17 pm

vanbcguy

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Re: Vanbcguy's M-TDI Build
« Reply #290 on: May 01, 2015, 03:15:17 pm »
Yup, that's exactly what it is - trying to build 15 PSI of boost using 45+ PSI of exhaust manifold pressure doesn't really result in much performance.
Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #291June 24, 2015, 10:48:21 pm

vanbcguy

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Re: Vanbcguy's M-TDI Build
« Reply #291 on: June 24, 2015, 10:48:21 pm »
So I've made some serious headway with my electronic controller.  It's obviously been working well enough for me to be driving lots - I've put about 15,000 km on it - but I've never been one to leave well enough alone.

I've got it working REALLY REALLY well now...



EGT is in degrees, Duty is in % of usable range, TPS is 0-255, boost request and actual are in kPa (multiply by 10 for mbar, divide by 100 for bar, divide by about 6.8 for PSI)... Peak boost is 210 kPa / 2.1 bar / 2100 mbar / ~31 PSI

That's a highway onramp run, cruising as slowly as I could get away with in 2nd on a long onramp and then WOT on to the freeway.  My 3-4 shift was pretty fast, the log didn't even catch my foot coming off the pedal :D I do use some averaging on the pedal plus the logger doesn't show EVERY data point used by the actual control loop. 

The freeway has a decent uphill grade here too so this is a pretty solid test of my fueling levels and things.  Smoke is limited to a decent puff at tip in and then a light haze that's gone pretty quickly.  Judging by my peak EGTs (BARELY over 700C at the end of 4th, at which point I was going more than fast enough) there's still room for some more fuel :D

I've made some code changes that help make things a bit more responsive over the past little while... I've been somewhat conservative as earlier versions of my code had some issues spiking way over desired boost.  Now that things are well under control I can make it a bit more aggressive.  I think I'm also going to add a vacuum ball for the 'N75' as it does take a little more time than I'd like to close the vanes fully.

There's a little bit of jumpiness on the 2nd gear part of the run that I can see in my logs is me hitting the top of my max duty cycle map at that RPM, looks like I need to expand the available range there just a tad.  Again I was being fairly conservative with a lot of the settings while I got things under control.

« Last Edit: June 24, 2015, 10:52:03 pm by vanbcguy »
Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #292June 25, 2015, 05:01:15 pm

libbydiesel

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Re: Vanbcguy's M-TDI Build
« Reply #292 on: June 25, 2015, 05:01:15 pm »
That looks excellent. 

Reply #293August 22, 2015, 01:21:08 am

vanbcguy

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Re: Vanbcguy's M-TDI Build
« Reply #293 on: August 22, 2015, 01:21:08 am »
Well well well... What's this?



There will be more to this story.....
Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #294August 22, 2015, 02:14:32 am

libbydiesel

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Re: Vanbcguy's M-TDI Build
« Reply #294 on: August 22, 2015, 02:14:32 am »
That's great.  Looking forward to seeing more. 

Reply #295August 22, 2015, 12:06:24 pm

vanbcguy

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Re: Vanbcguy's M-TDI Build
« Reply #295 on: August 22, 2015, 12:06:24 pm »
I'm picking her up this Wednesday. 1993 factory AAZ car so my M-TDI is a direct drop in while the AAZ will go to Jezebel leaving me with a good car to sell.

I ALMOST feel bad messing with anything though, this car has only 125k kms on it, she's still a baby!

Sent from my XT1097 using Tapatalk

Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #296August 22, 2015, 10:47:24 pm

vanbcguy

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Re: Vanbcguy's M-TDI Build
« Reply #296 on: August 22, 2015, 10:47:24 pm »
Went out to drop off my wheels today, here's a couple more pics...

Driver's side is arrow straight, there's a couple minor blemishes on the passenger side.



Ever see an engine bay this clean on a 23 year old car before?



Interior is awesome, kid approves...





More once it's out of the shop...

Sent from my XT1097 using Tapatalk

Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #297August 22, 2015, 11:56:30 pm

libbydiesel

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Re: Vanbcguy's M-TDI Build
« Reply #297 on: August 22, 2015, 11:56:30 pm »
That's beautiful.  It'll be a fairly easy swap too.  The wagons are so much nicer than the sedans.  Someone else will get a nice sedan too.  Win win.  Congrats. 

Reply #298April 02, 2020, 01:12:46 pm

alvarok260

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Re: Vanbcguy's M-TDI Build
« Reply #298 on: April 02, 2020, 01:12:46 pm »
Hello, I suppose this topic is already super closed ???, but I am very interested in the project to implement it in a nissan patrol (sorry for my English, I am from Spain ;D) and I would like to ask you how you do to record the data in a graph, I suppose that from the usb backpack but I don't know what program to use. And I would like to know how to modify the pressure values ​​(Is this by means of the .ino tables?) Since I am going to mount a gt2052v and I wanted to work over 1.0 / 1.2 bar and that it works well at a speed low rpm (the engine is a 2800cc 6 cylinder rd28) and finally how to adapt the rpm signal since it takes it from the injector pump pulley. Greetings and thank you :)

 

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