Tuning Transients

[stevieturbo]

It's like flogging a dead horse trying to get through.

You claim you see a lean spike ? But does it have any effect at all on how the car runs ? probably not.

And maybe ( more likely ) it is a wideband issue, and nothing to do with transients.

IGNORE AFR's, tune for throttle response.

[FrankCorrado]

You claim you see a lean spike ? But does it have any effect at all on how the car runs ? probably not.

A double spike. Lean, then rich.
Now to answer the second question, holly shit yes. If I tap just too much the engine bucks wildly and brakes due to sudden huge loss of power. If I shift gear and tap on it too much further I get a back fire, the engine bucks and brakes hard. Of course the colder it is the worse it is. When warm it's less bad but well enough so that I have to completely adjust the way I drive. I cannot floor it quickly, I have to go smoothly until I reach TPS 100. And while doing that I get AFRs in the 16-17 and I can easily feel loss of power. Launching in first is also sometimes tricky, depending how the clutch engages, but I have found a way to manage around this, though the first meters of accel are made in the 16AFR or so.

And maybe ( more likely ) it is a wideband issue, and nothing to do with transients.

I wish. But it happens the same way in OL too.

IGNORE AFR's, tune for throttle response.

I totally agree. But the response is shit. It's like hitting a wall with the car every time I tap on it too quickly. So obviously I tend to check AFRs and that's why I say it's super lean. So far no matter what I did, transients on, off, small fuel%, huge fuel%, response times high, low, pedal opening high, low, CL on, off, nothing worked even to improve the response. That's when the stupid idea of running super rich everywhere crossed my mind, I wanted to see if I'd get a shitty response with that too. At the moment I am not tuning transients, I am testing how I can richen the first half of a second after tapping on the pedal. I have not found a way yet.

[stevieturbo]

I wish. But it happens the same way in OL too.

Nevermind flogging the fucking horse, I want to blow it up !!!

CL/OL has **** all to do with transients.

I'll repeat. The apparent lean spike you are seeing may purely be a function of the wideband.

Now that is a very simple statement to understand, so why dont you ?

In much the same way as you use your brain to read something and understand it. But if your brain doesnt work correctly, then you wont understand.
It doesnt mean the text is wrong, it's just the thing computing it isnt doing what it perhaps should be.

You are assuming the wideband will do exactly what you want/think it will do under all circumstances.

And I am baffled as you why you are STILL trying to complicate such a simple thing.

TURN OFF ALL TRANSIENTS.

TUNE YOUR MAIN MAP. Chances are it will drive perfectly 90% of the time with no transients whatsoever.

And then, AND ONLY THEN turn on transients and start at ZERO enrichment everywhere.
AND TURN CL OFF !!!
But if you are trying to tune transients when your fuel map is wrong, you are wasting your time.

Sit stationary and blip the throttle and start to add fuel until the engine blips smoothly. Using only the first section for around 1000rpm. Then this gives you a starting point. It probably wont need much enrichment at all.
Above 3-4000rpm any car Ive worked at has never needed any enrichment.
If at the lower end response is minimal at the pedal, you may need to use a very short "read" time at the pedal. ie a low pedal speed setting.

And notice throughout the entire very easy process not once have I mentioned looking at a wideband. Doing so will only **** things up and confuse you.

And I'll repeat that last comment. Doing so will only **** things up and confuse you.

I'll assume you can understand that, because throughout all your transient threads or queries, things are fucked up and you are confused.

Notice a pattern ?

Even on mine which is a 6.6 litre engine, and quite a large TB I use only 2% Pedal speed, 35% increase, duration 40, speed time 50 increase at 1000rpm
Whilst every engine is different, it shows a lot of enrichment is not needed.
Although I could drive with transients off and barely notice the difference 99% of the time

And dont even bother with cold transients until you have hot transients sorted.

[86sixsix]

IGNORE AFR's, tune for throttle response.

ahhhh... see... for me - those're potentially inclusive... i can't have one without the other.

agree with your last few posts, mind

[stevieturbo]

IMO the worst thing you could possibly do with transients....is get hypnotised by what a wideband says.

And this thread 100% proves that. I fact, make that 1000%

[86sixsix]

dunno... my method works well for both me and my motors. draw from that what you will

[FrankCorrado]

Ok, let's start on right foot here, cuz obviously I wasn't clear enough as to what I am trying to know (not do, know.), so the answers sometimes tend to go off track a little.

I'll repeat. The apparent lean spike you are seeing may purely be a function of the wideband.

I think I should repeat: CL or OL has nothing to do with my lean and rich (not just lean, as I said) spikes. The exact same behavior happens whether I run CL or OL. Therefore the wideband has nothing to do with these spikes. So please forget about that wideband thing. How hard is that to understand? I understood it right off the bat when I felt the engine responses in both OL and CL (exactly the same).

Forget AFRs, forget readings on the meter then, the response is shit no matter CL or OL, no matter the fuel I inject with or without transients function. Which tells me my map is not tuned fully yet. But that I knew already, no need to remind. The point here is I am trying to do a test and see how the engine would response to that test. Why can't I do that test? Why it wouldn't bring me anything good? That I don't understand.

You are assuming the wideband will do exactly what you want/think it will do under all circumstances.

About what? As said, it's the same in OL, without the wideband, so I am not assuming the wideband will do what I want, it's not even on when I try in OL, so it does nothing. loll

TURN OFF ALL TRANSIENTS.

They're never on. They don't do anything at this point of my map anyway, so why bothering turning them on?

TUNE YOUR MAIN MAP.

Why I need to do that to perform my 40% fuel increase test? I don't understand that bit. And that's not cuz I would be stupid, find another answer please.
If the engine runs at, example, 12.5AFR all the time, it will never buck, the response will always be good (cuz that's how my engine is at 12.5 and many other AFRs as well). So if I can achieve that during transients it should have a good response during transients (with transients off, meaning the map alone will provide 12.5 of fuel during transients). That's what I want to know and see if I can achieve.

But yes, to answer your tip, I am sill tuning now and for longer since that little episode I had the other day.

But if you are trying to tune transients when your fuel map is wrong, you are wasting your time.

Who said I was trying to tune transients?
I said I wanted to know if I can temporarily (for 2mins!) workaround my transients issue by adding a lot more fuel in the entire map. I never said I wanted to tune transients at this point, I am not ready for that. My map is not ready, I would waste my time tuning transients now.

Maybe there is something I don't understand. To my opinion, if I could run an engine at a constant say 12AFR under vaccum or at 0psi, no matter the MAP, no matter the TPS, temps, etc., the response during transients (at a 12AFR) would not make the engine jerk, buck, hiccup, hesitate and it should be smooth. Do I understand right or wrong? If I am wrong here, then I guess my way of thinking that adding a lot of fuel everywhere is useless and I would retract that possible test. But you have to convince me that having a lot of fuel (not too much!) during transients will still yield to lean spikes.



For the rest of your post, I agree totally, I'll keep that in mind for when I will be ready to tune the transients. That will certainly help.
My original post was asking on tips for transients and I think I have enough to try with all your answers, tnx.

Although I could drive with transients off and barely notice the difference 99% of the time

Which tells me I may have lean spots in my fuel map, hence the test to increase 40% everywhere and just see what the hell would happen and how the response would be. If all people are right and my problem is not enough fuel, then by having a lot of fuel it should work. If I am wrong here, then I did not understand something.

There's absolutely no harm at all to perform the test I am talking about, cuz it does not affect any map, any setting, any table at all. And, if I understand correctly (but maybe not!!), it will tell me if having more fuel really does help or not. If it does, then I'll continue tuning the map and wait until finished and at that time I'll know that transients will be fixed with fuel following all your tips. But if the test does not work, it will tell the problem is not fuel and to look somewhere else. This is why I want to do that test. I won't wait 3 months tuning my map and ending up with the same transients issue I have now cuz it would not be fuel related. And at the moment I do not trust fully it is, I have no proof it's 100% fuel related.

Why would the conclusion of increasing my map 40% not answer my question?
Forget the "it's stupid" and whatnot answers, but technically speaking, why having a lot of fuel everywhere would not get rid of super lean spikes?
Maybe there is something I don't understand.

[Roverdose]

I think I should repeat: CL or OL has nothing to do with my lean and rich (not just lean, as I said) spikes. The exact same behavior happens whether I run CL or OL. Therefore the wideband has nothing to do with these spikes.

does that not mean your main map is still rubbish?

Drew

[FrankCorrado]

No it's not rubbish. It drives smoothly (apart from transients), but not optimal in terms of AFRs.

What I mean is if I disconnect my AFR gauge and let someone drive the car he would not feel anything weird except the transients and he would think all is good.

I'm not finished with the map though, I still need a couple of months to make it more optimal and more linear, but the engine does not response abnormally, apart from the transients, which I am not tuning yet cuz I want to wait until I get a more optimal map.

[86sixsix]

keep driving it in CL with the transients off (as they are)... it'll come, frank dude. like in 'wayne's world' movie - "if you book them... they will come"

only when CL = OL in similar weather/what-have-you conditions can you consider progressing on to throttle pumps and the nitty-gritty pedal transitions and all that jazz. i'm sure i said this months ago...