SureShot

WhyteOut - If your max boost is staying below 8 PSI, then your setup is fine like it is.

Just keep an eye on it.

NZConvertible

Buy why is it an issue? You have no explanation for why you this this would be a problem. I've already explained to you that small amounts of fuel are not dangerous even if they could be ignited because they cannot generate enough heat. Do you have an explanation or not?

Whose? Certainly not the E6K you're looking at, nor the E6X or E11. All offer only one or the other.

There's nothing "he said, she said" about it. So far I've presented plenty of info explaining why fuel cut isn't dangerous when used properly. You haven't offered one single explanation for why it is. You say you don't trust 18yo technology but don't offer and technical reasoning behind your lack of faith. I'll ask again: What exactly do you think is going to go wrong?

I've read that site thoroughly and I've also read the manual cover to cover, so I know their system works on fuel or ignition cut, not both. The T-Sport flat-shift system you linked to has to cut both fuel and ignition because it can't rotate the cylinder cut like the Racelogic system can. It's as simple as that. There is no conflict of info here, T-Sport is just covering their *** by saying you must cut both because with their simple system it's true. With the more sophisticated Racelogic system it's not. In the case of the very short duration fuel cut on FC's the same applies.

I'm not interesting in those who've encountered fuel cut have taken steps to avoid it (that's most Turbo owners), I want to know about people who've suffered actual damage.

The common issues with these cars are very well known. If you're a forum regular you know exactly what to expect. It seems funny that problems like leaking PD's, failing wiper switches, cold solder joints in Logicons, the 3800rpm hesitation, stuck auxiliary ports, etc, etc are all so well know, and yet you never see any posts about fuel cut killing engines. Do you honestly think that if this were a serious issue it wouldn't be discussed? People would just rebuild their engines and not post anything about this? People bitch about the tiniest thing happening to their car, so I'm damn sure if this was a real issue we'd all know about it.

Not cornerstone, merely one of several aspects proving my point. If I had a cornerstone, it would be that fact that my engine is still running fine after hitting fuel cut quite often. The cause of that was eventually eliminated over a year ago and I'm still going strong. Many others will claim the same.

Like I said, the info isn't conflicting, it's a different application. You seem unwilling to offer any solid technical info to back up your theory, and don’t even have any valid counter-comments on mine.

WhyteOut

oh yeah. The Wankler, if you could shoot me an email or something that would be great. i had a question about a clutch. thanks. Seth_Parvin@yahoo.com thats and underscore between seth and parvin..

J-Rat

iTrader: (2)

Do you have solid empirical evidence that its NOT an issue? I had a website, you had a website. Why is the burden of proof laid entirely on me? And I am not looking at an E6K, I have been running one for over a year.

I have offered plenty of technical reasoning why I feel the way I do, and you have offered plenty of technical reasoning why you feel the way you do.

Hey, I am interested in that too! But I am not going to go around asking people to run up on fuel cut in the interest of science. Most people wont run against fuel cut for any lenght of time.

Well, every car has a PD, failing wiper switches, cold solder joints, etc.. But not everyone, (in fact, relatively few) of us are running the TIIs hard enough to hit fuel cut

Then in my opinion you were being a bit foolish. Once there was a problem, you should have dealt with it at that time. If your motor survived, then congratulations! Still not something I would recommend ANYONE do.

Sorry, I have made all the points that I felt salient to this conversation. Our respective positions are clear. I will continue to advance the premise that fuel cut is inherently dangerous, and you will continue to state that its perfectly safe. My reasons are my reasons. There apparently any reasoning that I have that will sway your opinions, and there isnt anything you can come up with that will alter mine. So we can continue to go back and forth, or not...

Oh, and BTW.. My E6K is on ignition cut, so is the 2-step...

Rat

Apparenty I am not the only one that feels this way:

http://bcrx7.com/modules.php?name=Fo...wtopic&p=26733

NZConvertible

Because the burden of proof is always on the person making the claim. Search for "burden of proof" on Wikipedia and you'll find this:

" Outside a legal context, "burden of proof" means that someone suggesting a new theory or stating a claim must provide evidence to support it: it is not sufficient to say "you can't disprove this". Specifically, when anyone is making a bold claim, it is not someone else's responsibility to disprove the claim, but is rather the person's responsibility who is making the bold claim to prove it. "

In any scientific or engineering discussion that's the way it is. If I claimed my car could fly, it's up to me to prove that it can, not for you to prove that it can't. You're claiming that fuel cut is dangerous, but have not given any engineering explanation for why this is, or any experience (yours or others) to indicate it is. I've given several technical reasons why the FC's fuel cut isn't dangerous and you haven't refuted any of them.

My bad, I misread what you said.

Where's this technical reasoning of yours?

And neither would I. Like I said, most people (including me) will lift off as soon as it hits so it lasts no more than a few tenths of a second. It also means when the engine is in a low-load situation when fuel is restored, so detonation is extremely unlikely.

What are you talking about? There are posts about fuel cut all the time, often from noobs not sure what it is. There would be only a few modified FC Turbo owners who haven't experienced it.

Neither would I, but that's very different to claiming it's inherently dangerous. Unless you can prove this you can't call me foolish. I had my reasons for needing to drive the car in that state and had no concerns about doing so. The fact remains that in previous discussions on fuel cut, many posted their experience of hitting fuel cut with no ill effects, but only one person I know of has claimed otherwise.

As I said, you haven't offered any explanation and you have countered any of the technical info I provided. "Your reasons" are not enough to make the claim that fuel cut is " fuel cut in itself is pretty damaging" or "inherently dangerous" unless you at least share those reasons with us. I've asked you several direct questions about why you feel the way you do and you've chosen to not answer any of them. That's hardly going to convince anyone of your position.

Again, nothing at all to back the claim up.

J-Rat

iTrader: (2)

And I missed the part where you provided engineering documentation and technical reasons stating that the FC fuel cut system (AND ONLY THE FC SYSTEM) is safe. So far all you have brought out is general documentation on modernized systems. Sorry, I am still not convinced.

Its stated several posts back, but I will recap.

1. The system is possibly old and outdated, possible the injectors wont seal and leak, possible residusal fuel in the system, possible misalignment of the planet Mars, and any other possible factors that can go wrong when running an engine in an abnormal condition. Thats all the reasoning I need.

Extremely unlikey is differnt then "will not happen". Not a chance I want to take with my motor at all.

And nothing to claim that its perfectly safe either. At this point in time I dont really care what refutable evidence you think I have brought to the table, I will continue to maintain that its an inherently dangerous condition to run your rotary in. Sorry I cant produce pages and pages of people claiming that thier motor was damaged by hitting fuel cut, or that I cant bring out some engineering document covering the L-Jettronic and its application to the FC, and any possible weaknesses inherent to its fuel cut system, but that documentation simply isnt available. I am just relying on my experience as a tuner, and what I know of day to day engine operations.

If you want the forum newbies to continue to quote you and your statement that its perfectly safe, then feel good in knowing that the day something bad happens because YOU said its safe (and I hope it DOESNT happen), the burden rests on your soulders. As evidenced, the person that encited this little discussion has had exactly NOTHING to add to it since he instigated the entire thing. So I guess there will be 2 schools of thought, because I will still continue to claim that its inherently dangerous.

We can continue to go around and around if you like, but the fact is, I cant convince you, and you cant convince me. We can move forward amicably, or we can continue to argue, but at this point, I feel the discussion is stalemated.


Rat

NZConvertible

Fuel cut is fuel cut. All it is is not firing the injectors. How does a modern system not fire the injectors differently to the FC's?

As an explanation this is literally nothing. You have still not provided any technical explanation for how damage may occur, despite me asking for this several times. I can only conclude from this that you just don't know, and a simply repeating that "it's dangerous" because someone else has told you and/or what you've read somewhere. What else am I supposed to think? You also can't explain exactly what our old and outdated system is going to do incorrectly. And I've already explained why residual fuel from leaking injectors is not dangerous, so unless you can explain why I'm incorrect you should stop mentioning it.

Statistically, it's extremely unlikely you'll be struck by lightening, which is why we walk around without fear of impending death delivered from above despite the fact that it can happen. Nobody has provided me any reason to believe fuel cut is "pretty damaging" or "inherently dangerous" as you claim.

When there is a complete lack of evidence that something is dangerous, it's a logical conclusion that it is not. I remind you the burden of proof in this case is on you, not me. And correct me if I'm wrong but I don't remember using the words "perfectly safe", so please don't imply I did.

So you do have direct experience with fuel cut causing damage? Why don't you share it with us? Or at least use this experience and knowledge to properly explain exactly how damage occurs.

Again, "perfectly safe" is not my words. Any newb who experiences fuel cut will get the same advice from me as they will from you; either lower boost or fit a FCD and fuel mods. I'm not encouraging people to go around banging into fuel cut regularly, I'm just not going to me making completely unfounded claims about it's supposed effects.

So how about all the questions I've asked you? Am I going to get any answers?

J-Rat

iTrader: (2)

Until you come up with irrefutable evidence that its NOT dangerous, I will mention it anytime I feel like.

Sorry, my arguments and feelings on this issue have been posted. This thread will remain so others can make thier own decisions based on the information provided.

NZConvertible

I already did. To repeat the info from Racelogic:

The simplest way of preventing a lean burn is to remove more than 50% of the fuel from the pulsed delivery. A mixture will only ignite if the air/fuel ratio is within a tightly defined window, look at the efforts being put into making lean burn engines fire on very low air/fuel ratios (1:20 or more). Removing more than 50% of the fuel will cause an air fuel ratio of over 1:25 and will result in a complete miss-fire, with the unburned fuel passing out through the exhaust valve. Even if a high air/fuel ratio did manage to ignite, the energy available from the amount of petrol injected wouldn't be enough to elevate temperatures significantly."

Do you dispute this info? If so say why, otherwise stop posting factually correct info.

So no answers then? Why not? Why don't you feel confident enough about your position to answer some very simple questions? You've posted your feelings, yes. Arguments, no.

J-Rat

iTrader: (2)

lol! And I posted info from T-sport!


So there is your answer.. Have fun! My position is clearly stated!

Rat..

Before I forget.. Source: http://www.tekniqauto.com/US/tsport/tsport.htm

Turblown

iTrader: (12)

Back on the subject of the thunderfabrications DP:

I have seen the welds break on those after 1000 miles. That was however just one downpipe. Just food for thought.

J-Rat

iTrader: (2)

My T-Fab has ran over 10,000 miles and has seen 350 hp.. No welds broken.

*edit* oh wait, it sees 350 daily on pump gas, but damn if I know anything about tuning...

NZConvertible

C'mon man, that info from T-Sport is pathetic and you know it. It doesn't explain a thing. The info on Racelogic's site has been well-know and understood for decades, and anybody who claims to have "experience as a tuner" and knowledge of "day to day engine operations" should have no trouble understanding this common knowledge.

You are correct that your position has been clearly stated. Your inability to answer my questions speaks volumes about your position. Your claims are worthless because you don't understand them yourself. If you did you would be able to explain them rather than just keep repeating them. If you feel you can add some useful techincal info to your argument please post it, otherwise you might as well just stick to discussing downpipes...

J-Rat

iTrader: (2)

I wasnt aware we were discussing the merits of the respective websites.. I am terribly sorry to have made that mistake. Back the claims on Racelogics site, and dispute the claims on T-Sports site... Not my issue now...

Have fun cottoning to the nubbins.. You are a real inspiration to us all!


So back to the part where my DP has allowed me 350 daily on a stock S4!

And the welds havent failed yet!

Later!

rat

NZConvertible

You haven't actually disputed any of the Racelogic info, and it would be amusing to see you try. That fact that overly lean mixtures won't ignite is common knowledge. The fact that residual amounts of fuel do not contain enough energy to create high combustion temps (and hence detonation) is common sense. This stuff has been known for a long time and is pretty obvious if you know anything about combustion chemistry. But in case you don't...

http://www.autoblog.com/2005/08/17/g...ne-technology/

"Lean-burn (air-fuel ratios above the “optimum” 14.7:1 ratio) technology has been used on spark-ignition engines, but with mixed results. It’s difficult to properly ignite a lean mixture with a spark, and the process usually results in excessive NOx emissions..."

Remember we're talking about mixtures much, much leaner than 14.7:1.

http://web.iitd.ac.in/~jpsm/mel713/C...N%20ENGINE.doc

"...the conventional spark plug system is quite ineffective when igniting a lean mixture below an equivalence ratio of about 0.8 for gasoline and air."

An equivalence ratio of 1.0 is stoichiometric, so 0.8 would be an AFR of 18.4:1. Again we're talking about mixtures much leaner than that.

"Plasma jets were shown to be capable of igniting gaseous mixtures below the normal flammability limit. Studies on single- and multi-cylinder engines have shown that with plasma jets, lean mixtures of the order of 18:1 could be ignited."

Do we have plasma jet ignition systems? Nope.

http://www.swri.edu/3pubs/ird2004/Synopses/039354.htm

"Experiments with homogeneous air/fuel mixtures were performed to study the effect of ignition spot energy density and the lean ignitability limit. The lean operating limit was extended down to an equivalence ratio of 0.5 [AFR 29.4:1] using the laser, in comparison to the limit of 0.6 [AFR 25.4:1] using the conventional spark ignition system."

Do we have lean-burning GDI engines with laser ignition systems? Nope.

http://www.pro-dyno.net/tuningintro.php

"At part throttle and low loads (cruise), very lean mixtures are possible with things such as high energy ignitions, charge stratification or special combustion chamber shapes."

This implies two things: that very lean mixtures are safe at low loads (and with the injector cut that's essentially the state of that chamber); and very lean mixtures required special engineering to ignite them (which FC 13B's certainly don't have).

So back to your leaky injectors and residual fuel. Leaky injectors make the engine hard to start because over a period of time fuel has leaked into the engine and upon cranking this washes the oil off the chamber walls, which drops compression. On a hot engine (with thinner oil) it seems to take about 15 minutes before flooding becomes likely, because fuel is only dripping out of the injectors very slowly. How much fuel do you think is going to leak out of those same closed injectors during a few tenths of a second of fuel cut? The amount of fuel we're talking about is going to be minuscule, a tiny fraction of the amount needed to have proper combustion. And even if it did ignite somehow, the amount of heat released would be correspondingly tiny and not nearly enough to cause detonation or damage.

So there you go, plenty of info explaining why leaky injectors and residual fuel are a complete non-issue during fuel cut. If you're going to stick to your guns, the least you could do is offer some logical, technical explanation of how you think fuel cut can damage an engine. And there's always all those questions...