Lets argue about VGT/VNT Diesel Turbos on a gas motor.
#22
The beauty of these turbos is that you can hold a target kpa/map, but then still adjust flow. Getting an ebc to do that would require a constantly moving target based on rpm, boost, or both. Basically you'd want your target to be a sliding scale that looks like a Rotrex power curve.
Not sure how close MS Ebc could come to that, but I bet it'd be way easier to set it up pwm vs. Rpm and just ignore load or map. Control psi levels independently with manual controller.
That said, he's not using megasquirt I don't think.
#26
You aren't understanding.
Your idea might work on a diesel... But as i just plainly said, you aren't going to be able to decrease boost by opening this ****** unless we're talking about setting it so small it's an engine brake to wide open.
It's simply not going to work once this thing is on boil at any sort of RPM.
As i just said: Wide open, and i mean WIDE open, it took a wastegate to keep one of these ******* to "just" 32psi on an F2T. That's a 2.2 litre motor. It wouldn't decrease boost by opening it wider, because it was already open all the way. Not sure how to make that more clear.
Your idea might work on a diesel... But as i just plainly said, you aren't going to be able to decrease boost by opening this ****** unless we're talking about setting it so small it's an engine brake to wide open.
It's simply not going to work once this thing is on boil at any sort of RPM.
As i just said: Wide open, and i mean WIDE open, it took a wastegate to keep one of these ******* to "just" 32psi on an F2T. That's a 2.2 litre motor. It wouldn't decrease boost by opening it wider, because it was already open all the way. Not sure how to make that more clear.
#27
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Yeah, I think that is exactly what Pinky was trying to do. No need for steam up top on autocross, so keep it in little AR mode. Then set it for the normal sweep for the drag race where you do want the extra power.
Or I've completely misinterpreted what Pinky was thinking (likely).
Or I've completely misinterpreted what Pinky was thinking (likely).
The majority of people adapting VGTs to gas motors fit an EWG actuator to the VG vane control rod, so at low boost it spools like crazy, and as you start building pressure it shifts to a more open vane setup, ultimately passing the most efficient point and beyond into bypass. It sounds to me like this would end up with a turbo that could possibly build boost at idle (no boost present on the WG signal hose, so turbo rests in Big Spooly mode. I'm hoping that the volume of exhaust at idle wont be enough to really spin it up, or it could get weird. (I'm imagining a sort of feedback loop where it's boosting at idle, which speeds it up, which adds exhaust gas volume, which boosts more, which speeds it up, and on and on....?)
Anyway, the fun is in the messing with it, and this seems the perfect platform to experiment a little. If it all goes wrong it'll make for good video and I'm only out a few himdred bucks.. But if it works, the sight of this beast of a turbo under the hood will be worth the trouble all by itself.
#28
It sounds to me like this would end up with a turbo that could possibly build boost at idle (no boost present on the WG signal hose, so turbo rests in Big Spooly mode. I'm hoping that the volume of exhaust at idle wont be enough to really spin it up, or it could get weird. (I'm imagining a sort of feedback loop where it's boosting at idle, which speeds it up, which adds exhaust gas volume, which boosts more, which speeds it up, and on and on....?)
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#30
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You aren't understanding.
Your idea might work on a diesel... But as i just plainly said, you aren't going to be able to decrease boost by opening this ****** unless we're talking about setting it so small it's an engine brake to wide open.
It's simply not going to work once this thing is on boil at any sort of RPM.
As i just said: Wide open, and i mean WIDE open, it took a wastegate to keep one of these ******* to "just" 32psi on an F2T. That's a 2.2 litre motor. It wouldn't decrease boost by opening it wider, because it was already open all the way. Not sure how to make that more clear.
Your idea might work on a diesel... But as i just plainly said, you aren't going to be able to decrease boost by opening this ****** unless we're talking about setting it so small it's an engine brake to wide open.
It's simply not going to work once this thing is on boil at any sort of RPM.
As i just said: Wide open, and i mean WIDE open, it took a wastegate to keep one of these ******* to "just" 32psi on an F2T. That's a 2.2 litre motor. It wouldn't decrease boost by opening it wider, because it was already open all the way. Not sure how to make that more clear.
Weird thing is that there are people somehow controlling these beasts; I'm taking a lightly traveled path here admittedly, but not exactly breaking new trails. In searching for info on whether it's even feasible I've come across numerous forum postings saying they were running VGT's, mostly with the cobbled up EWG actuator strategy I've mentioned, so I figured we'd give it a go. If it absolutely does not work I toss it's $150 *** on the shelf and go junkyarding for a conventional Holset. I'd need to plumb the EWG either way, so it's not really that big a deal. The only things that count towards the budget are the things on the car when you roll it into the GRM tech inspection.
Anyway, we'll see. The beauty of playing with a sub $2k car is the total lack of ***** associated with the possibility of spectacular, nay even epic failure. Lets strap it on, set a big *** wastegate to 12 psi and see what happens. I'll film it for sure.
#31
The highest shaft speed setting should be the tiny AR setting. Because ultimately the amount of air you flow is determined by the shaft speed. If you held exhaust entropy, flow, velocity, etc constant, as the AR increased the turbine shaft speed would decrease and the compressor would flow less air, which would make for less boost.
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Where would I buy this pop tart valve of which you speak? Don't roots blowers have something like that in case of backfire? I might be able to cobble up something back where the EGR used to live, using the springs they use to hold down a plate.. (?)
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The highest shaft speed setting should be the tiny AR setting. Because ultimately the amount of air you flow is determined by the shaft speed. If you held exhaust entropy, flow, velocity, etc constant, as the AR increased the turbine shaft speed would decrease and the compressor would flow less air, which would make for less boost.
(BTW, thanks for entertaining my screeching ignorance on VGT's - I appreciate being able to hear from someone with direct experience.
#34
Or you could rig up a ebay bov to open at a set pressure. I also know there were OEM ones of these.
And the bike annology isnt really correct. The tiny setting is going to give the exhaust gas the most push on the turbine, which also gives it the highest speed. Think of it more like gears in the car and engine braking. 1st gear give the most engine braking, but you cant downshift to first to engine brake when you're doing 80mph, because you'll overspeed the engine.
#36
Weld waste gate shut. Build servo to control flow of garden hose sprayer into airbox. Consider this "water injection".
Best of all, with a few wal-mart spray nozzles, and some McMaster Carr adapters, you could have port specific water injection. Spray a light mist at low RPM (think, watering flowers), and blast that ****** at 6k (Cleaning gunk from drive-way seams).
I know nothing about electricity, but I can promise you MegaSquirt can probably handle that. Or weld a spigot to the throttle cable mount, for extra ghetto-ness. More throttle = more water.
Best of all, with a few wal-mart spray nozzles, and some McMaster Carr adapters, you could have port specific water injection. Spray a light mist at low RPM (think, watering flowers), and blast that ****** at 6k (Cleaning gunk from drive-way seams).
I know nothing about electricity, but I can promise you MegaSquirt can probably handle that. Or weld a spigot to the throttle cable mount, for extra ghetto-ness. More throttle = more water.
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So, one of the guys at the shop just called me and said the turbo arrived. "It's kinda big" he says, accompanied by shrieks of laughter from the other idiots in the background...
"How big?" I innocently inquire...
"Really big. 80 pounds big."
Now, SuperTrav is occasionally given to exaggeration, and he's only been around little ***** turbos like my MSM turbo, so I figure he's just making a big deal about nothing. Besides, an *80* pound turbo? Fuggetaboutit, the dudes gotta be mistaken. But there's something about the howling idiots in the background that makes me curious, so I tell him to text me a picture of it.
Whoa. Now THAT'S a turbo.
"How big?" I innocently inquire...
"Really big. 80 pounds big."
Now, SuperTrav is occasionally given to exaggeration, and he's only been around little ***** turbos like my MSM turbo, so I figure he's just making a big deal about nothing. Besides, an *80* pound turbo? Fuggetaboutit, the dudes gotta be mistaken. But there's something about the howling idiots in the background that makes me curious, so I tell him to text me a picture of it.
Whoa. Now THAT'S a turbo.