OK so now everybody knows this problem exists does anybody think it might be a good idea to do something about it.

If the standard overboost system is too slow to shut the throttle on a modified car, or can't be set up because the boost sensor doesn't read that high, might it not be a good idea to put some other protection in place, I would put money on the overboost system protecting a standard car by the way.

How about a stand alone electronic device, it would have an independant boost sensor, and be wired into the injectors or coils. If your boost is set at 1.4 bars you could have it cut the fuel/ignition at 1.6 bar and put it back in at 1.2 for example.

This would prevent runaway boost / engine destruction.Saying nothing can save an engine if the wastegates become disconnected is just not true

Or maybe the tuners could programme this function into the ECU and use a higher reading sensor?

I'm glad the tuners in this thread are not responsible for modifying the control systems of nuclear power stations and oil refineries.

 

There is no problem... if you disconnect the same lines on a OEM car the car will blow up too..

that car had an after market Y pipe which they forgot hook up the lines and put the car in run away boost after they worked on it... pure and simple...

 

If it was that easy, why don't you make one?..make millions of dollars?...Don't you think someone would have done it by now? I'm sure Porsche didn't expect people to double the stock output with a stock engine. No real protection against stupid.
An yes, anyone that drives a turbo car, under boost, and doesn't watch their boost gauge periodically, is stupid. These guys knew they were driving a car with a 1.1 or 1.2 bar tune. Once the gauge reads ANYTHING over that, let off and investigate...don't keep your foot in it because it feels awesome...just my .02...

 

So true

 

There is no problem?

because it can happen to any 996t that stops it being a problem. Nice logic there

why don't I make one? I'm a control system engineer not an electronics development engineer.


And if anybody thinks they will notice and will take there foot off before damage in a runaway overboost situation I don't think so. If the standard system can't shut the throttle quick enough I don't think you will, especially if your focused on catching that car in front etc.

Just trying to give a different perspective on things, from somebody that works in a risk based industry.

And

 

Markski was referring to aftermarket tunes and if there was a problem with them. In this case the problem was the hoses were not connected. There is no problem with aftermarket tunes is what he is referring to. Helps if you read before jumping to conclusions.

 

Obviously this is a problem that could happen to all of us on a bad day even with standard TT cars, there needs to some form of solution, everybody said the TT was bullet proof, well this is clearly the achillies heel

 

Thats the REAL reason we blew engines

 

OK, let's not blow this out of proportion people. How many blown engines or even overboosts do we have in these cars due to deteriorated WG lines? None that I have heard or read of.

Now if you have a shop that works on the car and immediately puts there foot into it without ramping things up to be sure everything is working correctly... That's a whole different situation.

Let's not muddy the water and blow this up and make problems where problems are not. These cars are getting old and you should regularly check your lines for cracks / leaks and do boost leak checks regularly.

Plus I always have my boost gauge on display to be sure things are working correctly. Before I go full foot, I do a quick small run to be sure the boost is not going to high. I have an EBC - this is my standard practice.

 

The solution is preventative checks. It is not unusual in the aviation industry to have another person inspect your work. And when you disconnect a hose their is always a follow on ops check or leak test. The way to avoid it is to leak test your car everytime you remove hoses. Thy would have revealed this fatal error. And FWIW this is not an issue isolated to just porsches. It happens in VWs and Audi's. And those cars do not have a quick enough ecu intervention either.


And I would like to add further that even though this is a fairly cheap car now, we are still playing a potentially expensive game in owning a 996TT. It is just the name of the game. The risk we take on this car is expensive plain and simple. I respect Richards professionalism and patience with this issue, but their is just no real solution other than double and triple checking your work.

 

There is something wrong with the explanation of the function of the n75 valve. On one of the drawing I got, the N75 helps the spring to close (the first one at the beginning of this thread) and on the other one work against it to help opening of the valve earlier than the spring force. In the past I have read that some people are running with spring pressure only. That mean Porsche engineer design a spring that provide a protection against high boost since the N75 is helping the spring to open the gate earlier ????? I think the second drawing explain the protection we have....Plus why the ecu would aloud the engine to continue running if it knows there is too much air for the amount of fuel it can provide. There has to be a maximum the ecu is able to handle by some kind of limitation.... I am trying to understand why, suddenly, we got this catastrophic failure that we never had before....


Also look here: There was no catastrophic failure with a malfunction of the N75: https://www.6speedonline.com/forums/...rging-fix.html

 

There was some mis-information early in this thread. The wastegates are CLOSED unless there is pressure to open them and let the exhaust gas bypass the turbo.

Without the line hooked up, there was no pressure to open them thus they kept boosting.

They are not like air brakes where a line failure puts it in safety, a line failure on a boosted car will make them overboost. It is like owning a gun, you have to check the safety, otherwise bad things could happen.

 

Look at the link provided. "Janker" had a failure of his N75 and the maximum boost he got was 1.3 which is not something that will give you a bent rod or destroy your piston! I also don't understand why Porsche engineer did not provide any protection. (I know they are not perfect, vario cam, spoiler hydraulic,slave, etc etc...) I've read in the past many cases of N75 failure and never saw a failure like Richard's one. I am like you Chad and don't want anybody to panic about it and I'm trying to found answers....

 

And I guess there is no overboost sensor in OPs tune? Factory system will sense overboost and go into self protection, as I recall. (Although I will admit that it may not respond fast enough to protect in the event of a rapid increase.)

My guess is the stock system is 'fail-safe', but when you increase potential boost and eliminate other protections, this runaway scenario can occur?

 

I think you got my point Ard.....