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Author Topic: Fresh Air Antilag via SAI  (Read 28441 times)
prj
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« Reply #15 on: September 03, 2015, 12:19:37 AM »

Can our current implementation maintain spool while completely off the throttle and engine braking?

Can it kick in to help spool the turbo if you shortshifted and bogged the motor?

That stuff sounds like it could be useful to me.

Nearly anything you can do with a bypass like this you can do with an e-throttle. No problem to keep the turbo fully spooled all the time with an e-throttle whether you are touching the gas pedal or not.
"Your" current implementation does not allow it, because it is not WRC. All the hardware is there to do it, the only thing that needs to be added is code. Don't expect the turbo and manifold to last more than 1-2 races though.

Just because something costs 600k does not make it change physics.
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elRey
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« Reply #16 on: September 04, 2015, 12:30:05 PM »

And that 600k may include the 5 manifolds and turbos the car is expected to go thru ;-)
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zillarob
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« Reply #17 on: September 04, 2015, 02:35:09 PM »

Nearly anything

What about the 2 things in the post you quoted?

Just looks like an interesting way of doing things and might be easily adapted to our cars.
My guess is the ports in the head may be too small to have any real effect. The ones in the pics look to be pretty good size.
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zillarob
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« Reply #18 on: September 04, 2015, 02:38:51 PM »

And that 600k may include the 5 manifolds and turbos the car is expected to go thru ;-)

No kidding, they dont look cheap! But I dont think they go through them all that often.
Much of the engine, including the turbo, is sealed and tech keeps a record of how many changes there have been.

I wonder if it would be any harder on parts than what we already have?
Guessing close to the same and very dependent on how it is used.
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prj
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« Reply #19 on: September 05, 2015, 01:31:21 AM »

What about the 2 things in the post you quoted?

Just looks like an interesting way of doing things and might be easily adapted to our cars.
My guess is the ports in the head may be too small to have any real effect. The ones in the pics look to be pretty good size.
Again, it is not needed. You can keep the turbo spooled all the time without this. It is not "interesting" it is just old.
Audi used a similar system called "umluft" in the 80's in Group B rally.

No kidding, they dont look cheap! But I dont think they go through them all that often.
You are wrong. Bang-bang antilag means that turbos and manifolds are changed very often.
Plus, very expensive materials must be used for them to last at all.

Manifold/turbo lifetime with a such system when used with standard materials has been quoted at 50-100km.
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zillarob
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« Reply #20 on: September 05, 2015, 06:16:51 AM »

I must be missing something here  Huh
Lets make sure we are on the same page with the differences between this and our current systems.

This one can work in two modes. The normal one we have now, and a bypass mode.

The normal mode shouldnt need any further explanation. Im fairly certain you know more about this part than I do anyway  Wink

The bypass mode is the interesting one. It is not just bypassing the throttle blade or holding it open, it pretty much bypasses the entire engine.
This lets the turbo basically run itself, kinda like this vid  Grin https://www.youtube.com/watch?v=KI5wAeJUbsA

I think this allows them to do (at least) two things that we are currently not able to.
Close the throttle blade for engine braking (overrun for the guys on the other side of the big water?) and still maintain spool.
Kick in to help spool the turbo when you are at an rpm lower than the turbo would normally spool.


I wasnt at that race as a spectator. I mean it when I say they dont go through that stuff all that often.
Turbos and manifolds are most often changed due to an engine problem.




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ddillenger
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« Reply #21 on: September 05, 2015, 08:11:58 AM »

Yeah, that doesn't look detrimental at all. Glowing turbine and all!
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zillarob
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« Reply #22 on: September 05, 2015, 09:54:44 AM »

I think that is how inconel tells you it is happy, it glows.

Shits hot, yo  Grin

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vwnut8392
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« Reply #23 on: September 09, 2015, 11:11:54 AM »

i started a topic on the same idea a few months ago and got bashed for it. nice to see someone is following through and actually using it!
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ddillenger
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« Reply #24 on: September 09, 2015, 01:24:55 PM »

i started a topic on the same idea a few months ago and got bashed for it. nice to see someone is following through and actually using it!

It

Is

Not

Needed

with an electronic throttle.
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prj
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« Reply #25 on: September 11, 2015, 10:50:44 AM »

The bypass mode is the interesting one. It is not just bypassing the throttle blade or holding it open, it pretty much bypasses the entire engine.
This lets the turbo basically run itself, kinda like this vid  Grin https://www.youtube.com/watch?v=KI5wAeJUbsA
It does not matter if you bypass air through the engine or you bypass it next to the engine whatsoever.
With an e-throttle you do not need additional things because you can just use it to bypass as much air as you want without affecting the pedal.

Quote
Close the throttle blade for engine braking (overrun for the guys on the other side of the big water?) and still maintain spool.
You do not need to close the throttle for engine braking. It is enough to cut the ignition/fuel which has exactly the same effect. You can argue the engine does not pull vacuum then, but what creates engine braking is mostly internal engine friction.

Quote
Kick in to help spool the turbo when you are at an rpm lower than the turbo would normally spool.
And that you can do too by just bypassing air through the engine. The turbo does not spool because of "low rpm" the turbo does not spool because of not enough volume of exhaust gas.
No problem to create said gas by holding the throttle wide open and throttling the engine using other means.

I do this stuff for a living, I have experience doing it both ways. You can keep this up, but first I recommend a book on basics of internal combustion engines, then a lot of stuff will be much clearer to you without having to spoonfeed it to you bit by bit.
« Last Edit: September 11, 2015, 10:52:53 AM by prj » Logged

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vwnut8392
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« Reply #26 on: September 11, 2015, 04:33:14 PM »

follow this link to some detailed info about "umluft" on the audi S1 rally car. it even has pictures of all of the hardware that audi used in specific to make their setup work.
http://www.bufkinengineering.com/Umluft.htm

 i do agree with PRJ that there are better ways to achieve this sort anti-lag through retarding ignition. the retarding of the ignition along with wide open throttle is a hair safer than the way audi used to do it although its going to ruin engine parts eventually. over all what audi did was use a porsche wastegate as a diverter valve which in turn vented the boost air from the charge piping directly into the turbo manfold when at the same time they would either stop the ignition or retard the timing allowing the fuel that was supposed to be burned in the cylinder to enter the turbo manifold with the oxygenated air from the charge piping and the heat from the manifold would cause it to comubust in the manifold. the cut was activated by a closed throttle switch as well. i have seen pictures of the inside of an S1 and they have an umluft switch to enable the feature if the proper hardware is bolted to the engine.

i've seen people attempt to do this on old DSM's a few times over the past 10 years or so and every single time was a large fail. either their turbo blew the turbine wheel out the exhaust or literally blew apart the turbine housing, the manifold blew right off the front of the head or it burn the exhaust valves out of the head. either way the end result was not good for the engine at all.
« Last Edit: September 11, 2015, 04:40:01 PM by vwnut8392 » Logged
hopsis
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« Reply #27 on: September 11, 2015, 10:41:34 PM »

Old DSM's... I had one of those a long time ago. A '92 Plymouth Laser RS Awd. Good times Smiley
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zillarob
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« Reply #28 on: September 12, 2015, 11:26:50 AM »

Quote
It does not matter if you bypass air through the engine or you bypass it next to the engine whatsoever.
With an e-throttle you do not need additional things because you can just use it to bypass as much air as you want without affecting the pedal.

I would think displacement would matter to air going through the motor, no? Not a prob if you go around it. This is where I think the biggest prob would be, ports in the heads are pretty small.
Lets try and forget about the pedal. I think it is safe to say that most here understand the differences between dbw and dbc.

Quote
You do not need to close the throttle for engine braking. It is enough to cut the ignition/fuel which has exactly the same effect. You can argue the engine does not pull vacuum then, but what creates engine braking is mostly internal engine friction.

I hear what you are saying and agree with most of it.

Quote
And that you can do too by just bypassing air through the engine. The turbo does not spool because of "low rpm" the turbo does not spool because of not enough volume of exhaust gas.
No problem to create said gas by holding the throttle wide open and throttling the engine using other means.

This volume is why I am guessing they use it. You can throttle the motor by other means, but only up until you are giving all shes got.
Being able to circumvent the engine should let you run full tilt, and supplement this volume to keep the turbo in its happy place.

Quote
I do this stuff for a living, I have experience doing it both ways. You can keep this up, but first I recommend a book on basics of internal combustion engines, then a lot of stuff will be much clearer to you without having to spoonfeed it to you bit by bit.

I dont doubt you know your shit here, but there are reasons top level teams with unlimited budgets are currently running this.

The books and spoonfeeding comments are a little uncalled for, especially from someone who thinks friction is what primarily slows a car down when engine braking  Wink (just ribbin ya, I know you know better)

« Last Edit: September 12, 2015, 12:23:41 PM by zillarob » Logged
zillarob
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« Reply #29 on: September 12, 2015, 11:32:32 AM »

Old DSM's... I had one of those a long time ago. A '92 Plymouth Laser RS Awd. Good times Smiley

Lol, my cousin had one of those back in the day.
I remember it being all digital like knightrider, and I think it spoke spanish. I dont think he ever figured out how to change that shit  Grin
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