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Engine Specific Info and Questions => IDI Engine => Topic started by: Baxter on April 06, 2006, 09:07:29 am
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Heh, been reading around a bit and quite like the idea of a 2 stage boost controller for around town driving at more or less stock boost pressure and having a electropnumatic valve to bleed air when needed.
Thing that concerns me, okay, as I understand it, it is pointless having more boost without the fuel to go with it.
So, I fit a bleed valve and set the fuelling to suit the new boost pressure.
If I then revert back to stock boost pressure and leave the fuelling alone will I end up with a uneconomical smoke monster?
Again, not the most CI minded!
Any thoughts welcome.
System I was thinking of using was a t-piece from the wastegate actuator to a electropnumatic valve to a grainger valve.
So, actuate switch, open valve, bleeds air.
Sounds simple enough, just the fuelling part bothers me!
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i always thought the same as you, it'd be easy to set it up to run at different boost levels, but the fueling just won't work right.
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i always thought the same as you, it'd be easy to set it up to run at different boost levels, but the fueling just won't work right.
okay, yeh.. well. I'm no dieselgeek but yeah, too much fuel and not enough air would most possibly make waaaaayy too much smoke if the A/F ratio's are off
BUT
this is what I've found on the vhortex
http://forums.vwvortex.com/zerothread?id=2538407
Go down to the very bottom of the thread.... looks to me like an automatically electronically actuated fueling screw adjustment
I'm very VERY curious...
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I concur with libbypapa's post.
Here's another way, I drew this diagram a while ago:
(http://www.dieselinside.com/1.6td/lda_switch.jpg)
For the newbies; the LDA is generally the boost enrichment device on top of the fuel injection pump.
Disregard the LDA on/off switch for your application.
Leave the turbo's wastegate to open at max. possible boost. If I'm at low LDA and the turbo still manages to hit max. boost, then so be it. Naturally, the diesel's power is controlled by fueling.
It might however be better for the turbo's longevity to not always hit max. boost in case acceptable performance and exhaust opacity can be retained with lower boost (for your "low" stage setting). That said, have two air pressure sensors/switches prepared for the turbo's wastegate. The illustrated LDA switch will also select the pressure sensor/switch to use.
Get two Hobbs Pressure Switches at a local auto parts store; set one at medium boost, and the other at max. boost. For example, 15 PSI and 24 PSI respectively. Wire both switches to one solenoid/valve that passes air to the turbo's wastegate.
This way you will have medium boost + medium fuel, or max. boost and max. fuel by a flick of a switch. It is quite inexpensive to put together. It's also very simple to adjust the fuel + boost level for each stage, perhaps easier than customising the various LDA parts.
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this is what I've found on the vhortex
http://forums.vwvortex.com/zerothread?id=2538407
Go down to the very bottom of the thread.... looks to me like an automatically electronically actuated fueling screw adjustment
I'm very VERY curious...
I thought of something like that last year but didn't really have the drive. About time someone did it! Friggin' awesome. This may be the ideal solution to the high-idle problem if you already have the largest possible plunger (e.g. 11mm or 12mm) and perhaps large injectors, both of which I have yet to use.
This is the way I'd like the electronically actuated fuel "screw" to perform: The fuel "screw" by default will be pushed in as far as the engine idle will allow (i.e. no more than 1,000 RPM warm). If the factory WOT switch trips, then the "screw" propels forward as far as possible for maximum fuel. There's easily enough fuel for 1% to 90% throttle applications so an electronically actuated fuel screw that gradually moves (based on certain inputs) isn't needed - it should just move in or out (in 2 places). This should make a reliable solenoid.
How about a plug n' play version; you screw in what looks like a heli coil, a hollow screw, and a metal rod runs through the centre of the coil, which slides in or out (solenoid) for fuel control. If you need to change the default fuel level (while the solenoid's off), simply screw in or out the heli coil just as if you were to adjust the stock fuel screw.
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i just set my fuel for "kill",,and most of the time i do run it closed wastegate,,but it gets nice and loud,with wastegate open,,,,i found some "air switches" on a big truck,,,i did a little post about them somewhere,,,looks just like a normal electric switch,but has air fittings on the rear,and air goes thru it,,theyuse them for moving the 5th wheel,and locking axles and stuff,,,,try one of those,,i would just "series" it with your other boost controller(ie;iuse a shop air regulator),,,im never in it for too long anyways to worry about smoke/egt,,,,yea it smokes more on open wastegate,,but the afc is mostly turned up all the way anyways,,more conservitave,would probably be less smoky,,,you could use the air regulator set for whatever lets say 18 psi,,then whenyou need it,when you are init,,wack the switch to closed ,and see it go30+ psi,and fly http://www.vwdiesel.net/phpBB/viewtopic.php?t=3227
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This is all I was thinking...
(http://www.aumb39.dsl.pipex.com/uploads/2stage.gif)
Anyone see any problems with that?
All it is basically is like one of these
http://cgi.ebay.co.uk/Turbo-Bleed-Valve-Motorsport-Version_W0QQitemZ8054518388QQcategoryZ43120QQrdZ1QQcmdZViewItem
But electrically controlled.
Infact, you could use one of those, and the exit to atmosphere could go to the electro-pnumatic switch to turn it on and off.
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I concur with libbypapa's post.
Here's another way, I drew this diagram a while ago:
(http://www.dieselinside.com/1.6td/lda_switch.jpg)
For the newbies; the LDA is generally the boost enrichment device on top of the fuel injection pump.
Disregard the LDA on/off switch for your application.
Leave the turbo's wastegate to open at max. possible boost. If I'm at low LDA and the turbo still manages to hit max. boost, then so be it. Naturally, the diesel's power is controlled by fueling.
It might however be better for the turbo's longevity to not always hit max. boost in case acceptable performance and exhaust opacity can be retained with lower boost (for your "low" stage setting). That said, have two air pressure sensors/switches prepared for the turbo's wastegate. The illustrated LDA switch will also select the pressure sensor/switch to use.
Get two Hobbs Pressure Switches at a local auto parts store; set one at medium boost, and the other at max. boost. For example, 15 PSI and 24 PSI respectively. Wire both switches to one solenoid/valve that passes air to the turbo's wastegate.
This way you will have medium boost + medium fuel, or max. boost and max. fuel by a flick of a switch. It is quite inexpensive to put together. It's also very simple to adjust the fuel + boost level for each stage, perhaps easier than customising the various LDA parts.
What is the purpose of the restrictor?
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I concur with libbypapa's post.
Here's another way, I drew this diagram a while ago:
(http://www.dieselinside.com/1.6td/lda_switch.jpg)
For the newbies; the LDA is generally the boost enrichment device on top of the fuel injection pump.
Disregard the LDA on/off switch for your application.
Leave the turbo's wastegate to open at max. possible boost. If I'm at low LDA and the turbo still manages to hit max. boost, then so be it. Naturally, the diesel's power is controlled by fueling.
It might however be better for the turbo's longevity to not always hit max. boost in case acceptable performance and exhaust opacity can be retained with lower boost (for your "low" stage setting). That said, have two air pressure sensors/switches prepared for the turbo's wastegate. The illustrated LDA switch will also select the pressure sensor/switch to use.
Get two Hobbs Pressure Switches at a local auto parts store; set one at medium boost, and the other at max. boost. For example, 15 PSI and 24 PSI respectively. Wire both switches to one solenoid/valve that passes air to the turbo's wastegate.
This way you will have medium boost + medium fuel, or max. boost and max. fuel by a flick of a switch. It is quite inexpensive to put together. It's also very simple to adjust the fuel + boost level for each stage, perhaps easier than customising the various LDA parts.
What is the purpose of the restrictor?
one switch turns LDA on/off the restrictor allows a lot of pressure to go through to the LDA or a little, hence Lo/Hi
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Why restrict it and not bleed it?
How do you vary the restriction?
Sorry, it may seem really simple to you but it's really confusiing me!
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i think if you get too far into it, you're going to be better off to use a tdi electronic pump...
this is what I've found on the vhortex
http://forums.vwvortex.com/zerothread?id=2538407
Go down to the very bottom of the thread.... looks to me like an automatically electronically actuated fueling screw adjustment
I'm very VERY curious...
I thought of something like that last year but didn't really have the drive. About time someone did it! Friggin' awesome. This may be the ideal solution to the high-idle problem if you already have the largest possible plunger (e.g. 11mm or 12mm) and perhaps large injectors, both of which I have yet to use.
This is the way I'd like the electronically actuated fuel "screw" to perform: The fuel "screw" by default will be pushed in as far as the engine idle will allow (i.e. no more than 1,000 RPM warm). If the factory WOT switch trips, then the "screw" propels forward as far as possible for maximum fuel. There's easily enough fuel for 1% to 90% throttle applications so an electronically actuated fuel screw that gradually moves (based on certain inputs) isn't needed - it should just move in or out (in 2 places). This should make a reliable solenoid.
How about a plug n' play version; you screw in what looks like a heli coil, a hollow screw, and a metal rod runs through the centre of the coil, which slides in or out (solenoid) for fuel control. If you need to change the default fuel level (while the solenoid's off), simply screw in or out the heli coil just as if you were to adjust the stock fuel screw.
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and also another thought, which may make it easier to tune ur car into a good level, like stated previously, use a normal boost controller like in the ebay link, and then turn your lda up above where you would need it, put an air valve or just another boost controller in between the mainfold pressure and the lda. and if you run all the controls to the inside of your car you could tune it from inside. but i suppose that would just be a simpler design as some of the above ones, but it would make drive more fun, turn down the boost and open up the lda and let the smoke pour.
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and another thought, if someone wanted to be able to control the max fueling screw from inside the cabin they could attach something like a speedometer cable to it and then run the line inside the car and put a knob on it. just ideas, who knows how well they'd work...
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Why restrict it and not bleed it?
How do you vary the restriction?
Sorry, it may seem really simple to you but it's really confusiing me!
restricting is good because it keeps 'precious' boost air in. bleeding would be good for parts that require cooling such as the wastegate valve.
i'm sure the two stage lda controller wouldn't be too hard to make, just require lots of connections/parts $$. A solenoid could be used to switch between the Lo setting and the Hi setting.
Think of it this way. LDA - Off/Low/High
speaking of the electronic fuel actuator, I think its a great idea! On the highway I would want the least amount of fuel, as well as the LDA off, unless I came up on a hill. As said before our cars only need a certain amount of HP for a set speed. Considering our engines make around 54.2hp(stock) at around 3000 rpm (which is around 100km/h approx), power could be greatly reduced and still keep up on the highway.
45 mph: Too small to be replicable on the dyno
60 mph: 6.2hp!
70 mph: 12.8hp
80 mph: 29.2hp
above thanks to moTthediesel
Now I'm not sure if we could lower our engines power to 6.2hp @ 3000 rpm, but wouldn't that be sweet? It would have absolutely NO juice to pass, and hill climbing would ultimately suck, but being that it would be adjustable, you could flick a switch to increase fueling in stages, or using some sort of dial.
From a graph I'm looking at on the VAG manual, it shows that our engines consume 270g/kWh @ approx 3000 rpm. I'm not sure how to convert that to litres or what...
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i think someone should try doing this set up and make a faq, i am very interested.... but my car has no turbo atm, so i cannot raise my hand and volunteer :^(
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yea i guess its better to keep boost in,than vent it to atmosphere,,how doi restrict it,,take anyshop air regulator,withan airhose attatched,and put an open airchuck in it,with the thing closed,,start dialing it slowly,,air passes slowly,,turn it more,more air,,well just use this idea "backwards" to raise boost,,,,i do have a couple of those air switches around but idlike tofind one witha larger hose attachment,,,they only have like a 1/4inch airline push on fitting,,it may work ok,,,,actually something is wierd now using this turbo on the 1.9,,its lowest boost islike 14 psi,,used tobe like 10-11 on the 1.6,,must be extra exhaust volume overwhelms wastegate???????
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So, for a restrictor I could use the bleed valve like the e-bay link, but block off the vent port (un ribbed one) with a injector blank end, that would give me a adjustable restrictor.
(http://i2.ebayimg.com/04/i/06/23/bd/21_1_b.JPG)
The air switches are easy to come by from the AAZ and such, I was thinking of using the one that is used to open the wastegate. Old MKII polo's also have them, well, the Formel E's did in the line from the green vacuum reservoir. Think they wen't to the vac retard on the Dizzy. Anyway, by the by I have all the bits and some cool aircraft looking switches.
(http://www.alcester-racing-sevens.com/Ignition_switch_off_small.JPG)
Thing is though, if it's just a restrictor all it will do is slow the air flow down won't it? if you are cruising at a constant manifold pressure won't the pressures on either side of the restriction eventually even out? leaving you with a stock system?
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Well there are a few factors that will limit the amount of boost to reach the LDA. The restrictor will eventually leak out enough pressure to equalize both ends. For this to happen you would need full boost for at least 1-2 minutes. The fact that the fuel would be limited would also decrease the actual boost by a small amount as well.
I would have to say that in a daily driver it would be useable, but for someone who has their foot to the floor 90% of the time, it would be better to have the bleed valve since eventually when the pressure would even out, it would probably take that much time to release the pressure.
I suppose you could get fancy and use a regulator, but $$$.
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Depends on which turbo you are talking about.
If it's one with a poppet type wastegate, the wastegate should be designed to draw some air from the boost pressure diaphgram chamber by the valve stem/guide somehow, to help cool down the wastegate. So simply adding a restriction in the wastegate pressure hose will cause a pressure drop and raise the boost pressure. The 1.6lTD KKK for example has the boost pressure chamber on the diaphgram side where the wastegate valve stem is, so some of the pressurized air flows right into the valve guide around the stem. Cooling air for the the 1.6lTD Garrett wastegate flows through a much more convoluted path, traveling through a portion of the wastegate valve stem that is cross drilled.
However, if the turbo has a "swing valve" style wastegate, like the 1.9lTD KKK K03 turbo, I don't believe any airflow will be drawn away from the wastegate diaphgram pressure chamber.
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Oh right, the LDA! You are absolutely right. (Guess I need to pay better attention. :wink: )