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#30
by
blackbird82
on 13 Mar, 2011 10:07
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Of course you do get better mileage with advance, I never questioned that.
I just wanted quiet when casually cruising slowly, and when I am on the highway or doing anything that needs load it turns the advance on.
Oh, and don't ever confuse the governor on a VE pump with having anything to do with boost.
its completely controlled by speed, ie centrifugal forces.
I really enjoy this setup, but I have another AAZ engine I got(not running) gonna tear it apart this summer if I find a weekend and see what its like.
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#31
by
blackbird82
on 13 Mar, 2011 10:12
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truth be told I believe the next thing to better mileage on my motor is exhaust restriction due to too small of a turbo.
Mine has the garret T2 and I put in an adjustable wastegate.
When cruising at 110k the boost is around 8psi, but i dont think it needs to be. If I spike the throttle to pop open the waste gate and go back to where I was on the throttle the car seems to run better at around 6psi, then slowly the boost creeps up as if the waste gate closes. Maybe spring pressure is strong or the diaphragm leaks a bit.
Either way I found that when I set my waste to 18psi with my boost controller, versus shutting it and leaving it in stock wastegate oepration. my mileage suffered. This was over lots of tanks! haha 120km a day for the last 4 years.
But when I want power in town or anywhere, I set the boost to around 18 or so and vroom!
I think cruising it would be better to have as little boost as possible to reduce exhaust manifold pressure, similar to the way a variable gate turbo works.
Now my mind is at the task of figuring this out on an old car, with a tiny budget!
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#32
by
macka
on 13 Mar, 2011 11:00
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I've seen guys playing with a lawn mower throttle cable to control a vnt turbo on wheeling trips. One of the JDM toyota diesel guys has a vnt rigged into his diesel. He has the vanes open or about 1/8 shut on the trails when creeping and closes them fully on the highway once up to speed.
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#33
by
R.O.R-2.0
on 13 Mar, 2011 16:00
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I've seen guys playing with a lawn mower throttle cable to control a vnt turbo on wheeling trips. One of the JDM toyota diesel guys has a vnt rigged into his diesel. He has the vanes open or about 1/8 shut on the trails when creeping and closes them fully on the highway once up to speed.
that makes no sense.. so he has no boost at all on the trails, but is making like 15 psi going down the road when its not needed?
vanes closed = 45psi if you arent careful (position at idle on a TDI)
vanes open = 15-20 psi unless you REALLY got some fuel.. (position when @ WOT on a TDI)
when they are open, they point about directly at the turbine.. basically at a 90* angle.
when they are closed, the tip of one vane is about touching the tip of the other vane.. not even pointing towards the turbine.
if you close the vanes on a VNT and really get on it, there will be soo much EMP, and boost that something will let go. i blew a head off a block at one point, because i closed the vanes on my turbo too much, they werent even fully closed..
with the vanes fully closed, your engine will make 30 psi by 1800 rpms, but not have ANY POWER at all.. theres too much pressure holding it back..
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#34
by
macka
on 13 Mar, 2011 16:14
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I've seen guys playing with a lawn mower throttle cable to control a vnt turbo on wheeling trips. One of the JDM toyota diesel guys has a vnt rigged into his diesel. He has the vanes open or about 1/8 shut on the trails when creeping and closes them fully on the highway once up to speed.
that makes no sense.. so he has no boost at all on the trails, but is making like 15 psi going down the road when its not needed?
vanes closed = 45psi if you arent careful (position at idle on a TDI)
vanes open = 15-20 psi unless you REALLY got some fuel.. (position when @ WOT on a TDI)
when they are open, they point about directly at the turbine.. basically at a 90* angle.
when they are closed, the tip of one vane is about touching the tip of the other vane.. not even pointing towards the turbine.
if you close the vanes on a VNT and really get on it, there will be soo much EMP, and boost that something will let go. i blew a head off a block at one point, because i closed the vanes on my turbo too much, they werent even fully closed..
with the vanes fully closed, your engine will make 30 psi by 1800 rpms, but not have ANY POWER at all.. theres too much pressure holding it back..
the way I understood what he was saying is that he had low to no boost on the trail, as the torque from the diesel in the low end got him up and over obsticles. The boost on the highway was to pass easier. I guess when we idle pretty much all day up here in the rocks and trees boost isn't really needed. If we were mudding he'd want the boost to keep the tires turning.
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#35
by
R.O.R-2.0
on 13 Mar, 2011 16:19
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yea, see, i do alot of wheelin, not much crawlin..and i guess you dont need any boost when you have 42 transfer cases and go 2 mph wound to the bolts in low range.. (LMFAO)
my off road truck, i almost never use low range, and if i do, its in second gear.
i gotta keep my tires burnin to get thru alot of the mud we got here.. toyota V6's work good in the mud @ 7000rpms..
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#36
by
blackbird82
on 14 Mar, 2011 09:03
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still though on the highway vanes closed is insane, it would actually be counterproductive.
You would have so much EMP that it would actually slow you down.
You want all the boost you need and the LEAST amount of restriction.
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#37
by
blackbird82
on 14 Mar, 2011 09:04
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Rabbit on Roids, you one of the few guys on here that really gets it.
Proud of ya
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#38
by
R.O.R-2.0
on 14 Mar, 2011 12:42
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Rabbit on Roids, you one of the few guys on here that really gets it.
Proud of ya
do you have any idea how many people on this forum have told me otherwise? LMFAO..
ive had a FEW vnt turbos apart. i know how they work, and what the vanes do when open and closed..
i used to have a cable controlled VNT, it was a cable with a T handle.. you could use it as an exhaust brake, or use it to adjust boost. thats why i KNOW that it is not ideal to have the vanes closed down for driving down the road.. you want the least back pressure possible for any amount of given boost..
when i was young and stupid, i just set the vanes pretty much closed, and it went good, but got bad mileage, and i ended up grenading that engine.. almost lost the head off it.
anyways, thanks for the compliment! i appreciate it.
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#39
by
blackbird82
on 14 Mar, 2011 14:19
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The John Deere system for there VGT (Variable gate Turbo) which is similar to the VNT turbos, use a eletronic stepper motor to operate the gate(vanes).
They use a load sensing system based on transmission output
when you are goin full throttle under full load, they are NEVER closed!
They only close at idle, I've watched the screen when doing power tests. idle closed, load and hit the throttle, they open just slightly like 80 percent closed, then as the motor revs up they open more, the more load the more open they are because you so much fuel goin into the engine. at full throttle as the load backs off they only close if and I mean if boost drops from less fuel, but that hardly ever happens.
THis is why I am tryin to get my wastegate to open more on the highway. I want less boost under light load, a nice balance between boost and exhaust backpressure.
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#40
by
R.O.R-2.0
on 14 Mar, 2011 14:28
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The John Deere system for there VGT (Variable gate Turbo) which is similar to the VNT turbos, use a eletronic stepper motor to operate the gate(vanes).
They use a load sensing system based on transmission output
when you are goin full throttle under full load, they are NEVER closed!
They only close at idle, I've watched the screen when doing power tests. idle closed, load and hit the throttle, they open just slightly like 80 percent closed, then as the motor revs up they open more, the more load the more open they are because you so much fuel goin into the engine. at full throttle as the load backs off they only close if and I mean if boost drops from less fuel, but that hardly ever happens.
THis is why I am tryin to get my wastegate to open more on the highway. I want less boost under light load, a nice balance between boost and exhaust backpressure.
Regcheeseman has a setup similar to this.. its a pretty awesome design really.
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#41
by
blackbird82
on 14 Mar, 2011 14:29
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I wonder if a T3 would be better for highway cruising, must flow waaay better through the larger turbo. than my T2. hmm wonder if its a bolt on
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#42
by
R.O.R-2.0
on 14 Mar, 2011 14:55
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I wonder if a T3 would be better for highway cruising, must flow waaay better through the larger turbo. than my T2. hmm wonder if its a bolt on
T2 and T3 should be interchangeable, manifold wise. dunno about oil lines and charge piping..
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#43
by
dodger21
on 14 Mar, 2011 15:51
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The John Deere system for there VGT (Variable gate Turbo)...
IDK what JD calls it but I have always read in Holset and Garrets literature that it is Variable Geometry Turbo, as the geometry of the vanes change.
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#44
by
blackbird82
on 14 Mar, 2011 16:09
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Yeah those are different, like most things JD has their own things. On a John deere turbo the vanes do not twist like in a lot of applications. IN fact the housing is wider than a standard turbo and the vanes are a set angle and they move in and out!
They use it for their EGR and emissions systems. they close the turbo to make excessive EMP and forcde exhaust gas into the EGR cooler.
trick eh? oh and they have a speed sensor on the turbo itself, you can watch it like a tach, some hit 120,000 rpm. Now that would be a cool dash gauge.