stevieturbo

I already mentioned that is a possibility, but not without it's risks too. That can cause a massive rise in EGT's.

it is better than a serious overboost and detonation, but not as safe as a full cut.

It could actually be better to place two MAP loads sites close together and drop fuelling to zero in a very short space of time.

Say for a normal running MAP of 200kpa. create loads sites of 215 and 220kpa. And at 220kpa do a total fuel drop to zero.

got-a-ls1

iTrader: (12)

yes cutting fuel is way less risky then dumping a shitload of fuel into a hot turbo and exhaust unburnt with very low timing. but like i mentioned in my post about cutting the fuel in the VE table, i dont know if there is a way around the minimum injector pulse width.. which makes me wonder if it would be safe. My thinking is moving as much as as you would be moving and only having ~1ms pulse width probably wouldnt even ignite because it would be so lean. then you would run into the factor of bouncing between fueling cells and fuel cut cells... wouldnt be a problem as long as your paying attention and let off as soon as you feel the motor fall on its face.

black98ws6ta

iTrader: (77)

If you set the tune to go richer and very low timing you would tell right away that something happened and get out of it. In that same time you really couldn't hurt anything motor related due to egt's. Only way it would hurt something is if the guy stayed reaming on it not noticing it has lost hundreds of hp.

got-a-ls1

iTrader: (12)

that is IF you have enough fuel in such a high boost situation.. Youd be surprised what a lot of people would miss especially if they didnt build the car. any setup could cut out the fuel.

black98ws6ta

iTrader: (77)

All you have to do is remember to do it in the tune or so specify it from the tuner and test it. It doesn't have to have more fuel, a drastic decrease in timing would be fine. Its free and works everytime.

I also agree that you could zero out the ve table at the boost level you wanted to cut fuel. Even at a min pulse width It would be so lean that it would not fire.

got-a-ls1

iTrader: (12)

problem with timing is at 1.2 g/cyl its maxed out, atleast with hptuners custom os. thats only around 4-5 psi. i dont know about efi live

black98ws6ta

iTrader: (77)

There are ways around that if someone wants full functioning timing tables.

got-a-ls1

iTrader: (12)

im interested in that workaround

Adam123

iTrader: (1)

I like that Idea with the crank sensor! I'm getting some type of tuning software in March. Haven't yet determined whether or not I'll go EFI or HP.

Johnv

EFILive custom operating system has a boost timing table, giving easy control of timing in boost without having to manipulate the main timing tables.

chasgiv3

iTrader: (1)

Are you folks over thinking this? Or maybe I'm the crazy one. I've seen this type used in the past to protect excessive boost creep or worse complete wastegate failure or lock.
http://www.ipgparts.net/store/Go-Fas...rotection.html

Turbo Fuse This is a nifty little device that acts as a last line of defense against an over-boost situation that could ultimately blow up your motor. It plugs in line with your BOV vacuum hose, and when the user-adjustable trip-point is reached, boost pressure to the top of the BOV is instantly cut off, which cracks the BOV open and relieves boost pressure. This prevents possible engine damage and alerts the driver that something is wrong.

stevieturbo

And have you ever ran a boosted car with no signal to the BOV ?

It might surprise you how much boost they hold before they vent. It would be incredibly stupid to rely on that for engine safety.


And as for the crank sensor wiring. Given how critical it is, I would not be interfering with it's wiring to add a switch to it.

chasgiv3

iTrader: (1)

Ok so I should cut all my wiring, solder, add relay, heat shrink all the cut wires, zip tie and try to make look nice with flexible cable tubing and still have dangerous issues with the tuning perhaps? Sorry man....nice that you're trying to save a little cash but for $150 shipped to my door I can use what's already been proven in racing over and over.

The other solutions was a tunable hobbs switch with a ferocious light on it that scares you into letting the go fast pedal go. Not as good but certainly cheap.

Sorry but I just don't see it.

stevieturbo

Why spend $150 when you dont need to spend anything ?

Simple ecu tuning methods have already been mentioned. They're effectively free.
And if you did go down the crude pressure switch route, there is very minimal wiring that needs altered to achieve it, and certainly nothing dangerous.

A pop off valve is a also very crude and far less effective way to protect against overboost, and also introduces risks to the turbochargers themselves

chasgiv3

iTrader: (1)

Nothing surprises me there Elvis. I test my setup for proper operation before I make a full boost pass and have tested just about every scenario. Many of them on the bench first. I run dual wastegates and blow off valves. For me to have a complete failure I'd have to have two parts fail at the exact time or be stupid enough (as you insinuated) to not check all connections and use reliable parts on my build.

I do see that you suffer from diarrhea of the mouth however. And clearly that is incredibly stupid on your part.

stevieturbo

Nope, I deal only in facts. If you are incapable of understanding those facts, then you have the problem.

chasgiv3

iTrader: (1)

You say crude and I say simple and effective. It does require some common sense on the drivers part however. But please I'm truly interested to hear your scenario for causing turbocharger damage. I could use a little fun on a slow work day in the dead of winter here. Entertain away.

stevieturbo

It's very simple. WOT, turbo spinning very fast under boost, and suddenly there is no resistance as air is vented to atmosphere, the turbocharger overspeeds and the compressor wheel explodes.

It even happens some turbos without allowing the air to escape uncontrolled. That's why turbochargers have a compressor map showing safe operating speeds etc.

chasgiv3

iTrader: (1)

That's why I did state that it requires some common sense on the drivers part. In order to overspin the turbo the driver would have to hold down the throttle while it's venting wildly into the atmosphere. Definitely not a normal sound AND you're losing all your power. At that point (the common sense aspect) you would undoubtedly take your foot off the throttle and coast to where it was safe and check everything out. Hopefully logging the run and realize that you were overboosting your setup and investigate as to why.
I equate it to a driver (even a naturally aspirated one) flooring the car on a run and then feeling it break up and just stay in it even though it felt like it broke up and lost power. Just need to have some common sense.

But I do agree that overspinning can and has happened before. I remember a few stories about folks driving their small displacement motors where the intercooler hose came off and they were driving up large hills and causing overspin and it shook itself apart.

killernoodle

It only takes a second or two at WOT to overboost a turbo. This is akin to blowing a charge pipe and keeping your foot in it, it will overspeed the turbo and probably blow it up.