Wastegate failure protection circuit
12-25-2011, 07:46 PM
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Wastegate failure protection circuit This is a set-up I've been working through my head to prevent engine destruction during a wastegate failure. Note that coil and injector wires will have to be cut from any factory fuse block and wired on a custom fuse block.
I will be adding part numbers and websites later. Also note that I suck at paint.
I think this would be a good way to protect those high price motors we built.
This is a simple circuit and will be very cheap to make.
I will be adding part numbers and websites later. Also note that I suck at paint.
I think this would be a good way to protect those high price motors we built.
This is a simple circuit and will be very cheap to make.
12-25-2011, 08:12 PM
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http://www.ebay.com/itm/Boost-Pressu...#ht_645wt_1132
Something like this for hobbs
Fuse Block Housing kit (terminals included) www.rockauto.com 85668 qty 2
Relay Socket www.allelectronics.com SRLY-2 qty 1
Relay 30 Amp www.allelectronics.com RLY-351 qty 1
http://www.allelectronics.com/make-a...RED-LED/1.html indicator light qty 1
You may want to change the terminal size on the relay socket if so here is the info
Relay Terminal 14-18 AWG www.mouser.com 571-42238-2
Something like this for hobbs
Fuse Block Housing kit (terminals included) www.rockauto.com 85668 qty 2
Relay Socket www.allelectronics.com SRLY-2 qty 1
Relay 30 Amp www.allelectronics.com RLY-351 qty 1
http://www.allelectronics.com/make-a...RED-LED/1.html indicator light qty 1
You may want to change the terminal size on the relay socket if so here is the info
Relay Terminal 14-18 AWG www.mouser.com 571-42238-2
12-25-2011, 08:26 PM
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The relay is to switch power off when hobbs is activated. 87a will feed inj and coils, when hobbs is triggered (86) power is taken away from 87a (powering injectors and such) and sent to 87 (indicator light.
This will pull power automatically
This will pull power automatically
12-25-2011, 08:46 PM
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You can do away with the relay and just use the hobbs by using the normally closed leg of the switch to power the coils/or injectors fuse block. and use the normally open leg for the indicator light. the relay isn't needed.
I think this would be a cheap fail safe. I'm going to build one for my car once I get to that stage.
I think this would be a cheap fail safe. I'm going to build one for my car once I get to that stage.
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12-25-2011, 10:14 PM
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really depends on how much current the hobbs switch can handle. i cant imagine the coils draw a ton though... but for such a critical component for the car to run i would want to assure a high quality connection that i wouldnt have to worry about over heating, corroding or whatever.
ive thought about protecting the motor within the tune itself. Im planning on running 12 lbs of boost and if much over that taking out all of the fuel. Say at 190-200 KPA set the ve table as low as possible. Only problem is i know the motor will default to minimum injector pulse width and what i dont know is if this in itself could dump enough fuel to burn **** up... i mean the motor would fall on its face so badly that i dont think anything could really happen and it would be fairly obvious to let off the throttle. the other thing i worry about is after it reaches that 200kpa point its going to fall back down into the lower kpa regions very quickly and bounce back and forth... but atleast maybe it would alert you to a problem before a melt down. dont know lol
ive thought about protecting the motor within the tune itself. Im planning on running 12 lbs of boost and if much over that taking out all of the fuel. Say at 190-200 KPA set the ve table as low as possible. Only problem is i know the motor will default to minimum injector pulse width and what i dont know is if this in itself could dump enough fuel to burn **** up... i mean the motor would fall on its face so badly that i dont think anything could really happen and it would be fairly obvious to let off the throttle. the other thing i worry about is after it reaches that 200kpa point its going to fall back down into the lower kpa regions very quickly and bounce back and forth... but atleast maybe it would alert you to a problem before a melt down. dont know lol
Last edited by got-a-ls1; 12-25-2011 at 10:34 PM.
12-25-2011, 10:39 PM
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Yeah the tune sounds like a good idea too. The engine would still be getting fuel, maybe not enough to hurt it.
I don't like just using the hobbs switch, I like the relay idea bc I know a relay can handle 30amps. I've been thinking about using a hobbs, a relay, and a 10amp circuit breaker for this little project.
The hobbs will trigger 86, 87a feeds the fuses for injectors and coils, 87 is grounded. 30 would be coming from circuit breaker
So when hobbs is triggered 87a loses power and then the circuit is grounded causing the 10amp breaker to trip. Once tripped the engine dies and the breaker has to be reset b4 the engine starts back up.
I know this is overkill but I would rather do a little more rather than replace my engine.
I figure I will mount the breaker on the dash. This is the Breaker I'm thinking of using.
http://www.allelectronics.com/make-a...BREAKER/1.html
I don't like just using the hobbs switch, I like the relay idea bc I know a relay can handle 30amps. I've been thinking about using a hobbs, a relay, and a 10amp circuit breaker for this little project.
The hobbs will trigger 86, 87a feeds the fuses for injectors and coils, 87 is grounded. 30 would be coming from circuit breaker
So when hobbs is triggered 87a loses power and then the circuit is grounded causing the 10amp breaker to trip. Once tripped the engine dies and the breaker has to be reset b4 the engine starts back up.
I know this is overkill but I would rather do a little more rather than replace my engine.
I figure I will mount the breaker on the dash. This is the Breaker I'm thinking of using.
http://www.allelectronics.com/make-a...BREAKER/1.html
12-26-2011, 05:35 AM
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He does have a fair point though.
All aftermarket ecu's have a user definable overboost protection. I'm guessing the OEM ecu does not have this, even with custom operating systems ?
Surely it wouldnt be hard for HPT or EFILive to implement this, if it isnt available ?
it is a very basic and sensible thing to have.
Although if you have a SD tune, you can also tune the loads sites above your normal boost pressures in such a way as to make them safe should an overboost situation arise.
Either by pulling timing and adding lots of fuel. Or like an overboost fuel cut, totally cut fuel at a load site when an overboost situation has definitely occured.
All aftermarket ecu's have a user definable overboost protection. I'm guessing the OEM ecu does not have this, even with custom operating systems ?
Surely it wouldnt be hard for HPT or EFILive to implement this, if it isnt available ?
it is a very basic and sensible thing to have.
Although if you have a SD tune, you can also tune the loads sites above your normal boost pressures in such a way as to make them safe should an overboost situation arise.
Either by pulling timing and adding lots of fuel. Or like an overboost fuel cut, totally cut fuel at a load site when an overboost situation has definitely occured.
12-26-2011, 06:37 AM
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Another wastegate is $$$, I've added the parts up and I'm only looking at 38 dollars to build this. Since I'm building a hybrid, I can just add this little fail-safe to the harness. It would take me 15 minutes to build.
I'll be running a sd tune in my car, but I don't have tuner software at the moment. Once I get it and learn it I'll try to implement on the tune as well.
I know I'm in to my engine for 5k and I don't have any of the FI parts yet. Machine shop bill on just the block and rotating ***. was 2459 and TSP got me for 1400, cam, springs, pushrods, OP, Ls2 TC, HG, etc. Then intake, WP, Accessory drive, etc. over 1k. I think this 30 of parts for a peace of mind isn't bad.
I'll be running a sd tune in my car, but I don't have tuner software at the moment. Once I get it and learn it I'll try to implement on the tune as well.
I know I'm in to my engine for 5k and I don't have any of the FI parts yet. Machine shop bill on just the block and rotating ***. was 2459 and TSP got me for 1400, cam, springs, pushrods, OP, Ls2 TC, HG, etc. Then intake, WP, Accessory drive, etc. over 1k. I think this 30 of parts for a peace of mind isn't bad.
12-26-2011, 08:44 AM
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i would go with it man, the principle seems sound just need to make sure the hobbs switch is high enough above your desired boost level as to not trip inadvertently.. also i would probably not do the circuit breaker thing as i dont think it would be needed and may cause a dangerous situation.. just think flooring it flat out at 100 mph and if something tripped going from full power to a dead engine braking could cause loss of control.
12-26-2011, 10:40 AM
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I understand you want to do this electronically, and you have already shown your disapproval of spending money on more hardware. But... Figured I would throw this out there any ways.
On the 1984-89 300zx turbo, they utilize what is called a pop off valve. It is sort of like a blow off valve, except it goes on the intake. If your boost pressure ever got above a certain amount, (I believe 9 psi on the z31) then it would open, venting access pressure out of the intake manifold. It would also cause your car to run like crap while it was open, since the system is a MAF based system.
That being said, When it comes to protecting something as vital as an engine, I personally would rather rely on a back up piece of hardware, than electronics. I also would not be concerned with spending another couple hundred dollars if it would save my many thousand dollar engine.
Either way, I think your idea is a good idea. My AEM EMS had an over boost cut out option in it. It was there, so we used it. We hit it a couple times and it may have very well saved my engine.
On the 1984-89 300zx turbo, they utilize what is called a pop off valve. It is sort of like a blow off valve, except it goes on the intake. If your boost pressure ever got above a certain amount, (I believe 9 psi on the z31) then it would open, venting access pressure out of the intake manifold. It would also cause your car to run like crap while it was open, since the system is a MAF based system.
That being said, When it comes to protecting something as vital as an engine, I personally would rather rely on a back up piece of hardware, than electronics. I also would not be concerned with spending another couple hundred dollars if it would save my many thousand dollar engine.
Either way, I think your idea is a good idea. My AEM EMS had an over boost cut out option in it. It was there, so we used it. We hit it a couple times and it may have very well saved my engine.
12-26-2011, 10:58 AM
#15
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I understand you want to do this electronically, and you have already shown your disapproval of spending money on more hardware. But... Figured I would throw this out there any ways.
On the 1984-89 300zx turbo, they utilize what is called a pop off valve. It is sort of like a blow off valve, except it goes on the intake. If your boost pressure ever got above a certain amount, (I believe 9 psi on the z31) then it would open, venting access pressure out of the intake manifold. It would also cause your car to run like crap while it was open, since the system is a MAF based system.
That being said, When it comes to protecting something as vital as an engine, I personally would rather rely on a back up piece of hardware, than electronics. I also would not be concerned with spending another couple hundred dollars if it would save my many thousand dollar engine.
Either way, I think your idea is a good idea. My AEM EMS had an over boost cut out option in it. It was there, so we used it. We hit it a couple times and it may have very well saved my engine.
On the 1984-89 300zx turbo, they utilize what is called a pop off valve. It is sort of like a blow off valve, except it goes on the intake. If your boost pressure ever got above a certain amount, (I believe 9 psi on the z31) then it would open, venting access pressure out of the intake manifold. It would also cause your car to run like crap while it was open, since the system is a MAF based system.
That being said, When it comes to protecting something as vital as an engine, I personally would rather rely on a back up piece of hardware, than electronics. I also would not be concerned with spending another couple hundred dollars if it would save my many thousand dollar engine.
Either way, I think your idea is a good idea. My AEM EMS had an over boost cut out option in it. It was there, so we used it. We hit it a couple times and it may have very well saved my engine.
So does either HPT or EFILive offer any sort of overboost cut feature ? if not, why not ? ( Ive never used either, so not familiar with them )
Given many of the custom operating systems are intended for boost, it would seem obvious to have such a feature.
A mechanical pop off valve is crude and could lead to overspeeding the turbos
12-26-2011, 11:32 AM
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Virtually every OEM turbocharged car has a built in boost cut. ie electronics. So clearly that is the sensible and easy way to achieve it.
So does either HPT or EFILive offer any sort of overboost cut feature ? if not, why not ? ( Ive never used either, so not familiar with them )
Given many of the custom operating systems are intended for boost, it would seem obvious to have such a feature.
A mechanical pop off valve is crude and could lead to overspeeding the turbos
So does either HPT or EFILive offer any sort of overboost cut feature ? if not, why not ? ( Ive never used either, so not familiar with them )
Given many of the custom operating systems are intended for boost, it would seem obvious to have such a feature.
A mechanical pop off valve is crude and could lead to overspeeding the turbos
I agree that a mechanical pop of valve is crude. That is why it was 80's technology. However, I would much rather over spin and destroy my turbo than over boost and destroy my engine. Maybe that was the thought of the Nissan engineers at the time. As far as I know, the later version of the 300zx turbo did not have any such feature. They probably realized it was not needed.
12-26-2011, 12:13 PM
#17
You are way overthinking this entire project , easy and simple overboost protection, keep the hopps switch and have it wired to a resistor that's wired to the iat, many nitrous do this its called the timing tricker, but anyways when you hopps switch closes at your desired psi, it shows the pcm super high iat (depending on what resistor you use ) and you pull all the timing out of that cell block in hpt
12-26-2011, 12:34 PM
#19
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Wastegates can sieze. Wastegate plumbing can split or fail ( or simply come loose )
There are quite a few ways an overboost scenario can occur. And it does seem amazing that HPT or EFI dont have an overboost cut built in.
As I said, every single aftermarket ecu out there has the feature. And virtually every OEM turbo car has it.
Seems very backwards that the current setups available dont have it.
Boost control is a very simple matter. Yet there are never ending threads were people are having problems. That alone highlights the need for safety backups.
