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Old 01-24-2013, 03:40 PM   #51
Dubstar112
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Yes, my current set up sucks and literally provides no flow to the manifold as evidenced by the extreme turbo surging that is quickly dying out. I need to bypass a lot more air to the exhaust manifold, and use less in the motor.
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Old 02-13-2013, 08:59 PM   #52
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Don't think anyone posted up the whole article from motoiq, just the teaser. http://www.motoiq.com/magazine_artic...preza-sti.aspx

In need of the "rocket"? http://www.subaruwrcspares.com/11.html Love this site!!!
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Old 03-04-2013, 10:32 PM   #53
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Been reading up on the Evo SAS system, it seems very simple. Once the ECU see's its within the parameters to turn it on, it just retards the timing on throttle lift-off to get fuel into the exhaust, then opens the dump valve to let air into the manifold, creating combustion in the turbo. Did i get that right? What can we use in our ECUs that can run a solenoid to do that?
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Old 03-05-2013, 12:10 PM   #54
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that is the VERY basic idea of the system indeed
In order to make it function properly it does take a good amount more tuning than you might expect. If you wanted to correctly run this on stock subi ECU i'm sure it is possible but i wouldn't expect writing that patch would be an easy task not to mention when running a rally style ALS it is VERY important to have some fail safes so you don't melt and or over spin the turbo.
Don't get me wrong, I would love to see the stock subi ecu controlling a secondary air injection set up
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Old 04-03-2013, 11:41 PM   #55
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Thought i already shared this here but guess not. Set this up on a KA24-t running V1 AEM, I have a few video clips floating around as well i'll post up as soon as i can. (Should have been a lot of clips from the track but we were rained out!)
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Old 08-21-2013, 02:36 AM   #56
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sorry for the delay, silly busy and haven't found the time sit down and upload the video yet.
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Old 08-29-2013, 05:46 PM   #57
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for anyone looking for it...




And for those of you already running this kind of system, how are you feeding the charge air into the manifold? I mean is the air pressure enough to overcome exhaust pressure, or is their some sort of slick setup going on inside the exhaust... like a venturi or something?
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Old 08-29-2013, 06:14 PM   #58
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Quote:
Originally Posted by blubug_768 View Post
for anyone looking for it...




And for those of you already running this kind of system, how are you feeding the charge air into the manifold? I mean is the air pressure enough to overcome exhaust pressure, or is their some sort of slick setup going on inside the exhaust... like a venturi or something?
The ALS motor controls the flow into the chamber. Please see pic below.

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Old 08-29-2013, 11:56 PM   #59
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ya their are many companies that make valves for this exact application, but that wasn't the info I was trying to get.
here's one from dsps
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Old 08-30-2013, 10:53 AM   #60
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Quote:
Originally Posted by blubug_768 View Post
ya their are many companies that make valves for this exact application, but that wasn't the info I was trying to get.
here's one from dsps
The DSPS units are all vacuum controlled units, they were all on the Citroen, Ford, Skoda and mitsubishi WRC cars, good units along with their external wastegates.
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Old 08-30-2013, 02:12 PM   #61
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I'm not running such a system, but I'll chip in because I've thought about it rather a lot and I can probably make an educated guess.

When the style of antilag that we're talking about (bypassing air completely around the engine) is going, by definition there's not much exhaust flow - the throttle's shut. And by the whole point of the system, the turbo is spinning at around its working RPM. So there's not much pressure on the exhaust side and there should be quite a bit of pressure on the air side, so air should just flow the right direction if there's a valve open.

There's ways of getting a low pressure fluid to flow into a high pressure one (look up steam injectors) but I don't think it's necessary in this application.

I could be wrong of course; I think, of people who actually post on this forum, only logic246 has worked on the full bore WRC cars.

Thinking hard about making a lashup testbed to try to test some ideas... if I shop right I could have a small pile of Holsets ready to go.
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Old 08-31-2013, 08:52 PM   #62
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The Throttle is not closed as you still need air circulating through the engine to keep the engine making boost.
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Old 08-31-2013, 10:23 PM   #63
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the whole point in bypassing the engine is so you DON'T still need air circulating through the engine to keep the engine making boost. Your logic is off, logic246. AFAIK the engine provides fuel and heat, the bypassed air feeds the fire and exhaust pressure to spin the turbo is circa a "5th cylinder" as I've heard the rocket system be described as before. I mean people that build turbo jet engines out of old turbos don't have an engine providing crap yet they can over spin a turbo. Jacked throttle als, sure the throttle stays opened, but with bypass style if you had initial spark and fuel source you can have full boost with the engine off.
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Old 08-31-2013, 10:30 PM   #64
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So where does the boost go when you keep the turbo spooling?
You do know in the cars fitted with the rocket the off throttle boost is 3 bar ?
The whole system is based on keeping the turbo spooling by not bypassing air totally but bypassing just enough to keep the turbo making boost you do not dump all of the boost you are making back into the exhaust. If the throttle is close then you would have no reason to put in any timing for the ALS to work you would just have a valve that shuts and opens to bypass the air totally.

But hey what do i know .
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Old 08-31-2013, 10:49 PM   #65
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goes to the boost pack? IDK

I've heard higher numbers as for the off throttle boost. I know that the rocket system is super sophisticated and the als valve will throttle itself to achieve the exact amount of boost the engineers want to have, but absolutely none of this has anything to do with the question I originally axed. I'm not trying to be an internet forum hero, I'm trying to learn about these kinds of systems.

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If the throttle is close then you would have no reason to put in any timing for the ALS to work
What do you mean by this?
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Old 08-31-2013, 10:55 PM   #66
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The boost pack only controls the boost. That boost can you pictured there stores pressure to activate the wastegate which has 2 ports, it is pressure to open and pressure to close the wastegate.

The 3 solenoids on the top regulate the pressure going out to the actuator and bleed off air accordingly to control boost. The pressure sensor at the side takes a pressure reading and all of that goes back to the ECU in order to control the boost on and off antilag.

If like you claim the throttle is fully closed and you bypass all of the air back into the exhaust there is no reason to have the ignition timing retarded and fuel trims turned up for the ALS. That is what i meant.
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Old 09-01-2013, 12:26 AM   #67
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I assumed ignition was retarded for spark to light off the system and then to reduce torque, and under no circumstances can I think of a situation where als wouldn't need fuel. That's interesting about the boost pack though, I had no idea about that.
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Old 09-01-2013, 02:26 AM   #68
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Old 09-02-2013, 12:30 AM   #69
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^OMG that's about as stupid as it gets, so the car idles at 5k. that's comparably stupid to the "als" where the iat sensor is turned off.
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Old 09-02-2013, 06:25 AM   #70
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Quote:
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^OMG that's about as stupid as it gets, so the car idles at 5k. that's comparably stupid to the "als" where the iat sensor is turned off.
I am with you on that one. That is just a glorified launch control.
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Old 09-02-2013, 10:45 AM   #71
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Quote:
Originally Posted by logic246 View Post
The Throttle is not closed as you still need air circulating through the engine to keep the engine making boost.
Hm, okay. I'm assuming that it was still *more* closed than when the pedal was to the floor though, which would have less mass flow out of the engine in terms of exhaust and so less backpressure before the turbine. I was figuring that when the rocket is working, pressure in the intake tract is probably higher than in the exhaust, so air will probably flow the right direction without any special trickery.

Full well could be wrong of course.
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Old 09-02-2013, 06:16 PM   #72
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that's what I thought until I read on another forum that exhaust pressure to boost ratio is ~2:1 and exhaust pressure will be constant at a given boost level. WRC cars might be different due to their awesome turbos and exhaust systems though.
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Old 09-03-2013, 01:15 AM   #73
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Quote:
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that's what I thought until I read on another forum that exhaust pressure to boost ratio is ~2:1 and exhaust pressure will be constant at a given boost level. WRC cars might be different due to their awesome turbos and exhaust systems though.
The pressure differential between turbine inlet and compressor outlet can vary drastically depending on the turbo/exhaust system. (many competition vehicles monitor and pre turbine back pressure.)

In no situation should you ever end up with more pressure on the compressor outlet vs turbine inlet. You can indeed get very close to 1:1 however it is impossible to have more pressure on the compressor side (that would mean free energy, remember you can't get out more than you put in)

In regards to Anti lag systems the pre turbine pressure is raised by introducing combustion which drastically raises exhaust manifold/pre turbine pressure.
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Old 09-05-2013, 01:18 AM   #74
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...so how is the air able to be fed into the exhaust? I think I read somewhere about the Mitsubishi sys feeding the air right at the heads and when the exh valves closed their would be a moment of vacuum, but that's obviously not how the rocket sys works.
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Old 09-07-2013, 11:53 PM   #75
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Quote:
Originally Posted by blubug_768 View Post
...so how is the air able to be fed into the exhaust? I think I read somewhere about the Mitsubishi sys feeding the air right at the heads and when the exh valves closed their would be a moment of vacuum, but that's obviously not how the rocket sys works.
The rocket system is 1 step above and beyond the simple secondary air injection set up. The so called "rocket" is what would more commonly be referred to as a "combustor"-combustion chamber used in jet turbine engines. The fact that prodrive has implemented this (in between the engine/turbo) and refined it so well is quite impressive.
Over all the combustor provides a more efficient way to power the turbine wheel rather than simply allowing combustion to happen in the exhaust manifold it happens in the combustor.
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