Fuel/Ignition cut @ 5500 RPM only on dyno...

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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby AvivB » Mon Mar 10, 2014 8:52 pm

Well, I can but...
I'm in Israel and there is only one place who have a DynoPack!!!
I don't trust the rollers dynos, I'm always afraid I'll find my car bouncing the closest wall...
In addition, the one who holds the DynoPack is a friend so I'm not paying for it...

Also, I want to figure the reason as I can not imagine a way the dyno csn be blamed for the fuel/ignition cut...
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby klue » Mon Mar 10, 2014 9:21 pm

klue wrote:
AvivB wrote:There isn't any setup like that in the dyno... and the dyno cannot stop the engine from reving.

I've started to suspect that the ECU have some kind of "no load" rev limit and it somehow notice the almost no-load condition on the dyno.
But as far as I know, the only way the ECU can detect load is by throttle position and this was fully open.



Yes there is, its called " set speed" its on the main streen which displays your real time output. You need to have the gear ratio calculations done or it wont work properly.

The ECU does not have a no load rev limit, or else it wouldnt rev past 5500 in netural. The ECU detects load from the AFM nothing more.
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby AvivB » Mon Mar 10, 2014 9:33 pm

klue wrote:
klue wrote:
AvivB wrote:There isn't any setup like that in the dyno... and the dyno cannot stop the engine from reving.

I've started to suspect that the ECU have some kind of "no load" rev limit and it somehow notice the almost no-load condition on the dyno.
But as far as I know, the only way the ECU can detect load is by throttle position and this was fully open.



Yes there is, its called " set speed" its on the main streen which displays your real time output. You need to have the gear ratio calculations done or it wont work properly.

The ECU does not have a no load rev limit, or else it wouldnt rev past 5500 in netural. The ECU detects load from the AFM nothing more.


As far as I understand from the dyno guy, this is only set the graph X axis max value.
You first calibrate the gear ratio (so the dyno can calc the rpm from the wheel speed) and then you tell it up to what rpm values to expect.
No matter what you will put there, it won't prevent from the engine reving if you press the gas peddle...
/Aviv

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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby brutekiller787 » Mon Mar 10, 2014 10:52 pm

Do you have a boost gauge attached? What is it reading at 5500 on the dyno
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby underscore » Mon Mar 10, 2014 11:22 pm

AvivB wrote:Well, I can but...
I'm in Israel and there is only one place who have a DynoPack!!!
I don't trust the rollers dynos, I'm always afraid I'll find my car bouncing the closest wall...
In addition, the one who holds the DynoPack is a friend so I'm not paying for it...

Also, I want to figure the reason as I can not imagine a way the dyno csn be blamed for the fuel/ignition cut...


If you secure the car properly it won't go anywhere. The DynoPack may be free, but if the issue is with your car and not the dyno then you might blow something up. One pull on a different dyno should tell you which of the two is causing the problem.
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby klue » Mon Mar 10, 2014 11:43 pm

Dude I dont mean to be rude, but I am the dyno guy.
Your issue is isolated to the dyno, thats because its how you guys have set up the unit. The set speed function lets you prevent the engine from reving past a set rpm. Which it calculates based on your gear ratio input.

So I asked you if you set the gear ratio correct, assuming you did then the dyno is calculating the right values for your RPM. In that case the only other variable is what you have the "set speed" option set to.

I usually use this to gradually step up the rpm so that I can tune a specific RPM with every available load point, so I am very familar with its function. You can download the dynapack software yourself and verify what I am saying. I could be wrong, but its the most obvious answer

Untitled.png


circled in red, this will hold the rpm to 3000 not any more, but you can go less.
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby AvivB » Tue Mar 11, 2014 12:17 am

underscore wrote:
AvivB wrote:Well, I can but...
I'm in Israel and there is only one place who have a DynoPack!!!
I don't trust the rollers dynos, I'm always afraid I'll find my car bouncing the closest wall...
In addition, the one who holds the DynoPack is a friend so I'm not paying for it...

Also, I want to figure the reason as I can not imagine a way the dyno csn be blamed for the fuel/ignition cut...


If you secure the car properly it won't go anywhere. The DynoPack may be free, but if the issue is with your car and not the dyno then you might blow something up. One pull on a different dyno should tell you which of the two is causing the problem.


I'm not trusting anyone here to secure anything right... and please don't let me start talking on that... :-)
From the other hand, I pulled on 3rd gear on the road up to the red line without any issue and I pulled it in natural up to there too...
The only combination I didn't try is to pull in gear but without load...

klue wrote:Dude I dont mean to be rude, but I am the dyno guy.
Your issue is isolated to the dyno, thats because its how you guys have set up the unit. The set speed function lets you prevent the engine from reving past a set rpm. Which it calculates based on your gear ratio input.

So I asked you if you set the gear ratio correct, assuming you did then the dyno is calculating the right values for your RPM. In that case the only other variable is what you have the "set speed" option set to.

I usually use this to gradually step up the rpm so that I can tune a specific RPM with every available load point, so I am very familar with its function. You can download the dynapack software yourself and verify what I am saying. I could be wrong, but its the most obvious answer

Untitled.png


circled in red, this will hold the rpm to 3000 not any more, but you can go less.

You're not rude at all, you know and I'm just trying to understand...
I have a question for you, let say you set 3000 rpm, how the dyno behave when you get to this rpm?
Does it apply load to keep the engine at that point?
How can the dyno cause something that feels and hears exactly like the rev limiter kicking in?

Ps. I belive my dyno friend doesn't know the software as you do so it might be that he configured something wrong... I just want to be super-sure I know what I'm talking about before I blame him...
Due to seafty and insurance issues he is unable to let me play with it by myself...
/Aviv

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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby klue » Tue Mar 11, 2014 2:07 am

I don't know all the fancy terms and what not, so bare with me.

What sounds like a rev limit, is because thats what its doing. It will not allow the engine to rev further than that but applying more load to the pods.

If your set speed is 3000 rpm. The dyno will prevent you from going any higher rpm/speed. So you can control the throttle to get your map into the different load points you need to fully tune the map. You can tune areas of the map that you would not get to under normal street driving. Say 1500 rpm, with maximum boost. You can only achieve that with the dyno as it creates enough load to spool the turbo fully.

The picture I posted, is the main screen when your operating the dyno actively, not in auto plot mode(where you do a full rpm sweep) so you guys can adjust it and see how it works. Be careful, you can easly induce knock this way.

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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby underscore » Tue Mar 11, 2014 4:09 am

With that software, is it possible to export the dyno configuration? Then you could maybe send it to klue and he could take a look at how your friend has it set up. Either that, or just take screenshots of all the screens.

AvivB wrote:I'm not trusting anyone here to secure anything right... and please don't let me start talking on that... :-)
From the other hand, I pulled on 3rd gear on the road up to the red line without any issue and I pulled it in natural up to there too...
The only combination I didn't try is to pull in gear but without load...


Fair enough, I know how hard it can be to find decent help. I think raising the car and bringing it to 7000RPM in gear would be sketchy though.
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby AvivB » Tue Mar 11, 2014 8:36 am

klue wrote:What sounds like a rev limit, is because thats what its doing. It will not allow the engine to rev further than that but applying more load to the pods.


They only thing i cannot understand is how extra load the dyno provided to keep the engine at specific rpm can sound like rev limiter....
For example, if I put my car on 5th gear and go up hill, I'll be in full boost and full throttle at low rpm but it still won't sound as rev limiter... no?
/Aviv

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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby brutekiller787 » Tue Mar 11, 2014 12:46 pm

Correct. It must be going like bum bum bum bum not just a steady rpm like a loaded single rpm dyno load. Sorry for the makeshift sound effects.
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby klue » Tue Mar 11, 2014 9:16 pm

AvivB wrote:
klue wrote:What sounds like a rev limit, is because thats what its doing. It will not allow the engine to rev further than that but applying more load to the pods.


They only thing i cannot understand is how extra load the dyno provided to keep the engine at specific rpm can sound like rev limiter....
For example, if I put my car on 5th gear and go up hill, I'll be in full boost and full throttle at low rpm but it still won't sound as rev limiter... no?



Define rev limiter? Device which limits engine revolutions? agree or disagree...

The dyno is now your rev limiter. simple enough?

More complex? well then we have ignition limiter, fuel limiter, and a new on we can call mechanical limiter(dyno). So your engine(hubs) is trying to spin the dyno at 3001 rpm, the dyno says no way, and forces the engine back to 3000 rpm. Thus you get the sound of a limiter which is the rapid change of airflow in the engine, or air stall. Does it really matter ? NO LOL

call your dyno guy up, tell him to open the plot, or send it to me and see if thats the problem. if it is great, if not then your back to square one.
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby AvivB » Tue Mar 11, 2014 10:11 pm

I'll start over since I'm feeling we miss each other somewhere...
My problem is that *only* on the dyno, my engine get ignition/fuel cut that sounds like bum bum bum bum which I don't see a way the dyno can cause it.
I understand that the "set speed" on the dyno will prevent me reving more than the setup but it won't sound like that... it will just be like starting to go into very hard up hill, no?

This is what make me going back to the beginning to figure out why the ECU/engine does it...

If you (or anyone) think how the dyno can cause the fuel/ignition cut (that sounds like bum bum bum), I'll be more than intrigued to hear.
btw, this "bum bum bum" on the dyno at 5500 rpm sound exactly like the rev limiter on natural at 7000 rpm...
/Aviv

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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby underscore » Wed Mar 12, 2014 2:04 am

AvivB wrote:I understand that the "set speed" on the dyno will prevent me reving more than the setup but it won't sound like that... it will just be like starting to go into very hard up hill, no?


No, IIRC and from klue's explanation it won't be a smooth cutoff (like bogging down up a hill). Have you been able to determine what the set speed is currently configured as yet?
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Re: Fuel/Ignition cut @ 5500 RPM only on dyno...

Postby klue » Wed Mar 12, 2014 2:32 am

I get what your saying and really I have no destinctive answer for you. What I am asking you to do is just TRY it. We are going back and forth and in circles, instead of either eliminating the problem or solving it.

Im giving you a posibility please stop asking whats the possibility of my possibility being possible HAHAHAHA TRY IT!!! :rofl:

Yes if your tuning say 3000 rpm its not going to sound like a fuel cut, but there are times I recall tuning and getting into the uper rpm and it sounds more like and agressive fuel cut which may or may not include a backfire. So my suggestion again : is ask your tuner for the saved files if he can look at it or I will for you.
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