Turbo cut out - open waste gate

[BFB]

So this is just a spin off of the other thread where oprn was talking about running a waste gate open on a turbo , so it didn’t spool.
So still have no idea why you’d want to do this but i just had a thought so thought I’d post it here and not side track the other thread any further.
Instead of trying to run a waste gate open all the time and trying to figure out a way to both hold it open and then shut it to spool the turbo then expect it to function as its intended as wastegate , run an exhaust cut out. They make them with both electric and vacuum actuators. With the vacuum one id assume it’s designed to open at WOT or near 0 vaccum? In which case the cut out could be set up to divert exhaust to the turbo. An electronic actuated one could be wired with a micro switch on either the gas pedal or carb to trigger at a certain throttle opening position to divert exhaust to the turbo.
Im not saying id set anything up this way, like i said before, it sounds like a bandaid for an improperly designed turbo set up BUT if that’s something someone wants to do, i thought this might work good

_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1

[oprn]

I suspect there could be a number of ways to accomplish that. The original one that was patented in 1966 used a vacuum actuator.

Also it is NOT a Band-Aid for an improperly designed turbo system. It is an aid to better drivability/versatility for a system that is intended to be street driven a lot and the focus is low to mid range power instead of just top end. The whole purpose would be to relieve the exhaust back pressure caused by the turbo when it is not being called on to provide boost for better fuel economy. If your sole focus is maximum top end then there is no place in your world for this concept. I highly doubt, after the firestorm this "empty headed" control scheme created previously, there is anyone on this site that is into boost that is the least bit interested in a concept that has the potential to increase economy.

It would be interesting to learn if any of the modern factory turbo systems do this. I am pretty sure the factory superchargers do.

It got you thinking though...
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Dale M.]

[BFB]

Just because i dont agree with an idea doesnt mean i dont think about its concept or that i dont like discussing it, anyone thats read even a few of my posts should know i like talking about ideas even if there’s not a current application im working on.

I think there’s several issues here regarding your “firestorm” , one there’s apparently a few of us that have gotten tired of seeing you post on what seems to be every single thread that exists , especially when your reply’s are just reiterating stuff you’ve read or has been previously posted and especially when you obviously dont have experience with the subject but post like you do. You need a disclaimer in your statements thats says “ ive read” or “ its been said”, something to that effect.
Two, you’re hung up on back pressure when people have showed you over and over that it’s nominal.
Three , the fact that you only have the one boosted buggy build under your belt and how you’ve said you built it, and your comments regarding boost all show your experience & understanding of it is limited. But you comment like you’re well experienced and have nothing to learn.
And four, this is stupid idea and the only AID it is IS a BAND-AID.

The whole concept is wrong, a turbo is not just a power adder for top end and race applications. Look at diesel engines which turbos have been used on for decades. Those are spooled at what, 1000 rpm maybe even sooner? not top end. Look at new vehicles , you’re seeing more turbocharged engines in everyday production cars used for daily drivers than ever before. Are these only good for top end? No. Like i said, these are daily drivers, designed with the average commuter in mind and FUEL ECONOMY. And in both of these examples the turbos produce usable power in low to mid range rpms. How and why are turbos being used so much in production vehicles nowadays? Because a turbo increases volumetric efficiency, let’s say that again kid’s EFFICIENCY! Yaaaaay! So if you have an engine that is more efficient and produces more usable power you can also use a smaller engine to meet the power requirements which a smaller engine will require less fuel too.
One of the key factors in all these set ups , and even in the top end rpm you mention , is the set up being thought out and built properly. Regardless of whether or not someone understands what a turbo’s AR is or if they can read a turbo map or not, just common sense will tell you that if the boosted engine you built is producing max boost at 1500 rpm and the engine seems to peter out at 3500 ( and its not a diesel) that the turbo is too small. And this turbo is more than likely very restrictive fo the exhaust in upper rpms and might make it difficult to drive in traffic. If on the other hand you built a set up where the turbo doesnt produce boost until the upper limits of your rpm range and your needing to shift before the turbo produces maximum boost, then its too large.
The fact that you can “control” your boost with your go pedal and that you dont even have a waste gate tells me that your turbo is improperly sized and is too large. And even though you’re not pushing the turbo to produce more boost than its designed to, running to large of a turbo like this is still using it outside of it’s designed parameters and is inefficient. Look at any turbo map and youll see the efficiency percentages.
I still say that the back pressure “issue “ would be nominal especially with an oversized turbo, but as i say that, you are constantly spinning a larger turbo which has more mass than a smaller one and if your not producing boost then yeh, maybe it could be an issue and yeh, it’s definitely inefficient and yeh maybe you would gain a little with bypassing the turbo? BUT this goes back to the setup being improperly designed & built.

Also, superchargers aren’t exhaust driven so why would this exhaust bypass concept even be considered applicable? I think what you’re referring to is a bypass the supercharger may have for over boost protection . Which is essentially the same functionality as the intended purpose of a turbo’s waste gate.
Which if the concept you’re talking about using was applied to a supercharger , you would be trying to hold that supercharger’s bypass open so as not to make any boost ….
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1

[modok]

I've been staying out of this, but I know a few things about it.
And I have my own theory about how to handle it, but, there are many possibilities.
Holding back the boost with the throttle is not efficient.
Can this be a problem?

Yeah it can be, and there are a few reasons it's MORE of a problem with a turbo VW than it is on other vehicles.
For one thing a diesel doesn't have a throttle in case you didn't know, so that solves that.
A lot of direct injected gasoline turbo engines run LIKE a diesel with the throttle full open in certain conditions, but the "throttle pedal" is just a sensor so you don't notice.
With a custom designed vehicle.... sometimes it isn't a problem at all, or sometimes it is. So many factors.

But it can be more of a problem with a turbo buggy because....... poor aerodynamics VS HP, limited rpm range, only four speed trans, long intake and exhaust manifolds, limited cooling.

Dual scroll, lightweight wheels, variable vane, electronic wastegates.
The better the turbo the better the performance all around, and the better the wastegate then the better the control.

I just get tired about how noobs think boost is magic, all turbos are created equal, and you just put them on and they just work.
I absolutely don't agree with that.
You can get all kinds of different powerbands characteristics depending on what kind of turbo you put on what kind of engine combo, and how the plumbing is arranged.
And wastegates aren't created equal.
Just have to keep fixing it until it works, trail and error.

[oprn]

My gut feeling was that this thread was not created to discuss a concept but just to draw me out for further public ridicule and humiliation. I should have listened to that and not dignified it with a response.

My mistake!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[modok]

Blowthrough superchargers will have an air bypass or clutch, or both.
My sc14 has the clutch on it, it's from a previa.

Drawthrough sc don't need it.
So the one in madmax was hollywood, not real.

It's all in the books.
Read the manual.
Try Advanced engine technology by Heinz Heisler

But another way to get a quick answer is post something wrong on the internet.
Worked, didn't it.

And IF you run into the problem just hold with a ziptie or a connect a cable going to a lever. Not big deal anyway. Or just don't drive that speed. Worry about it later.
Can make it CO2 actuated, bigger diaphragm, or servo controlled.
Some diesels have a throttle in the exhaust, it's a type of engine brake.
So that tells you something about what back pressure can do.

Old buick indycar motor that went up pikes peak this year, it has 7 throttles.
Why you think it needed seven throttles?
I'm not sure anybody remembers specifically what the initial reason was, but in any case it does work good that way, it's not the first at all, nor will it be the last. Worked then, works now, will work in the future too.
no surge, better response, reduced plenum flexing, improved scavenging at part throttle, dampens intake pulsations at part throttle, and turbo loses less speed between shifts.

But everybody knows a PROPERLY designed turbo system only needs one throttle and one chinese external wastegate and a whistling thingy to slow the turbo down when shifting so they must be doing it wrong using too many throttles.

[oprn]

A properly designed turbo system does what the designer wants it to do under the conditions he wants it to happen. Different control systems may or may not be a part of achieving that. What is right for one person is wrong for the next. That does not make the control system wrong, just wrong for you.
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Dauz]

[BFB]

[modok]

The rant was more aimed at the MIDDLE demographic that SHOULD BE here debating and educating eachother, so, I'm not surprised you didn't get all of it, and I greatly respect your honesty tho would be interested to know exactly where you didn't get.
the joke about blowoff valves will be super funny right after you learn how turbos actually respond to flow. So you aren't there yet.
never played with your shop vac? Block the flow of the inlet OR outlet....what happens?
There is a huge GAP in knowledge between the new guys and the old guys.

This problem is something we all need to do something about and I don't know what it is.

But..... I didn't learn all this stuff so I could teach which end of the nail goes in first, and which end of the ladder is up.
You'll get it when you are ready to get it.

You just can't predict what people know and what they don't know.
I'm suffering hard right now from this.

new guy has a high school diploma and 2 years of tech school doesn't know how to convert a fraction to decimal. Doesn't know how bolts work.
Why do we call this a half inch bolt.....is because it's dimensioned to fit in a half inch hole.
And that's fine. I can teach that easy....I think?
No, actually I don't know where to start.
I started with why there are 360 degrees in a circle. Maybe that was starting a few thousand years too far back.

but anyway......
Can a butterfly valve work as a wastegate? good question.
Not sure.
I suspect it has been tried and it didn't work better.
You gotta think what the heat path is.

Why do engines have poppet valves?
because it's symmetrical, like a funnel fits in a funnel. gets hot, it's still a cone. Rotates, still fits.
So a butterfly valve isn't symmetrical, it has one axle, where heat would exit out. Some of the rim is right near the axle and some of the rim is far from the axle, so you heat that up it won't stay in shape. Won't close fully when hot VS cold. Turns into a potato chip shape.
Assuming you know why potato chips are shaped as they are.

Why don't they teach this in school? Why don't you already know? Haven't you ever wondered why a potato chip is shaped like it is?
What I couldn't figure out was cheetos.
and it turns out they shoot them out of a nozzle and they solidify in zero gravity. Spent years wondering about why cheetos have no flat spots so when I found the answer I'll never forget it.

[BFB]

[chrisflstf]

Ive always liked turbo motors, but my complete lack of knowledge about them always kept me away. Too many ways to blow stuff up. Too many variables for a home built setup. I dont see anybody selling kits that are safe and thought out. Plus we have less turbo guys on here, than we do competent machinists and engine builders. The learning stage is pretty huge

Modok, tell your noob to google fraction to decimal calculator. Kids today are way behind...

[Dauz]

[58 Plastic Tub]

[oprn]

^^^This right here!^^^

I totally understand your frustration!

On this site there is only one way to build a boosted engine. If you do not fit that mold then you are a simpleton, idiot, have no idea what you are talking about and it would be so much better for the world if you would just shut up and go away! And Heaven forbid that you would want to discuss something that you have not tried!! Even if you had tried it, you must have done something wrong because it does not fit the norm.

If you want to see what can be done outside of the "norm", find the posts made by Clonebug and go follow the Dub Shop's latest 1600 turbo project. I did something very similar 30 years ago with the available tech I had to work with back then but apparently I was on bad drugs and hallucinating - it didn't happen and I know nothing. Don't listen to me!

There are indeed at least 2 ways to approach a turbo project. One is very expensive and the other... well "nobody" here does it.

Signed - Nobody.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[58 Plastic Tub]

I'd be happy with hearing the approved narrative, because most of the time- there's a way that works and a lot of ways that don't. I'd rather not skate off on thin ice (again) before the wise men on the hill have their say. I'm happy to read "the book" if I know what book to read, but the books Modok recommends are out of print or $35+ on Amazon. I thought the promise of the internet was the free exchange of information.

But asking for turbo combinations that work (as happens with NA engines almost weekly) brings mostly crickets, even when all the information is there and specific targets are laid out. Queeries bring one or two halfhearted posts and an off-topic flame war, rather than what I expected - which was 6 or 7 guys arguing why a 1776 with a big turbo was better than a 2332 with a small one, etc., not about when the wastegate should be open or not.

I know there are personalities and people behind various posts, but I don't troll here often enough to get all of the backstories. I graduated from Jr. High School a long time ago, so I would assume people could grow up and talk about what they know or don't know and try to help each other out.

I don't know if it's just that people don't know as much about a turbo T1 as they do about an NA engine or what - but whatever it is, there's not much information flowing here.
_________________
Stan Galat
"A single point in isolation is a reference point. Two points is a line. Three points is a trend. Trends don't lie."

[jimmyhoffa]

The reason a shop-vac speeds up when you block the inlet is because it's trying harder right? It knows it needs to try harder to achieve your goals, and it does because shop-vacs have big feelings.
_________________
1974 Chenowth 2RL #1244 Street Legal
My other car isn't ridiculous.

[modok]

You don't need that book, but it has a huge overview or engine controls and turbo controls.

Just research what turbo works best on a 300hp subaru.
Or, I'll ask my brother next time I talk to him.

[modok]