Author Topic: A weird day at the dyno  (Read 5033 times)

Offline Alexiskayak_7

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A weird day at the dyno
« on: October 08, 2013, 07:00:13 pm »
Yesterday, i booked a dyno to do a few pulls while i was remapping my ecu.
Basically, my targer was to do a few pulls with different fuel and ignition numbers (adding/reducing for both main maps), for my final paper research part.

Please note my g40, is totally stock.
I went to the dyno, they strapped the car and they fitted a LM2 wideband sensor at the exhaust tip.

At the firsth run, i got 112 hp and 165NM of torque (I was really impressed about the numbers, i didn't expect to make this kind of power/torque after 250.000km with a shitty g lader (with 0,5bar peak boost)

BTW....

The first thing that we noted was the AFR graph (at the first run)

It was unstable from 5300 till 5800

At the first 3 runs i made.
The red lined graph is stock
The green lined graph is leaner fuel values
The blue lined graph is richer fuel values.

The weird thing was that the more fuel i dialed the more unstable the map was (from less rpm)



Run after run AFR after 5000RPM was getting leaner and leaner

Adding ignition made no difference... NONE unfortunately.. Seems that the ecu was pulling back degrees of ignition

At he final run i got these numbers and a huge drop of power.


After a dissapointing reacerch,

I came to a conlution about my problem...

1)Faulty fuel pump
2)Faulty power supply to he pump
3)Dyno guy's broken wideband (I have a AEM wideband and it doesn't do show that it leans at this rpm values, thats the weird thing. Maybe mine wideband is broken?)
4)Some sort of problem in my emulation tools?? (I dont think so, but never say never)

What do you guys think???




« Last Edit: October 09, 2013, 01:02:44 pm by Alexiskayak_7 »

Offline Alexiskayak_7

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Re: A weird day at the dyno
« Reply #1 on: October 09, 2013, 06:21:02 pm »
Isn't it a bit weird???
My AEM wideband that its in car fitted goes down to 10.9 and it does not show any ups and downs in AFR

Also, i dialled 4 degrees of advance and it made no difference in power/torque

Offline GR40

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Re: A weird day at the dyno
« Reply #2 on: October 09, 2013, 07:49:00 pm »
Check for exhaust leaks after the stock sensor fitting! Maybe the pressure in the pipes at high rpm pops some connection and that is what the sensor at the end of the exhaust is picking! Also I doubt many people here have the experience needed to help you out! Maybe a couple do but they need to pay attention to your post first so be patient! Nice figures on the dyno for a high km engine with a crappy charger!

Offline Alexiskayak_7

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Re: A weird day at the dyno
« Reply #3 on: October 10, 2013, 12:28:38 pm »
I think that its a fuel pump issue.. Probably, its getting warm and it looses pressure... I'll measure it
Also, its maybe a faulty AFR gauge (dyno man's)...

I got amazed too of the figures to be honest...

Offline Yoof

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Re: A weird day at the dyno
« Reply #4 on: October 10, 2013, 12:57:33 pm »
I'd not trust any lambda shoved up the tailpipe for calibration changes. You need it pre-cat sampling from all 4 runners as close as possible to the engine (in stock position is good).

Fueling clearly isn't adequate, check the health of all components asap.

Also these engines are very sensitive to ignition timing, so I doubt adding 4' has had no affect at all, are you sure you're using the correct map? What software are you using?


Offline Alexiskayak_7

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Re: A weird day at the dyno
« Reply #5 on: October 10, 2013, 05:45:00 pm »
I'd not trust any lambda shoved up the tailpipe for calibration changes. You need it pre-cat sampling from all 4 runners as close as possible to the engine (in stock position is good).

Fueling clearly isn't adequate, check the health of all components asap.

Also these engines are very sensitive to ignition timing, so I doubt adding 4' has had no affect at all, are you sure you're using the correct map? What software are you using?



My AEM wideband sensor is fitted after-cat. I also increased ignition timing and i got shitty results

I have a pressure and flow fuel tool gauge. How much should i expect at wot (3.5 bar and how much flow?)

I did another run, i added 7 degrees and the result is to loose more power... Unfortunatelly, i can't data trace maps so i don't have a clue about what is going on..
Can you please confirm me that the main ignition map is the only one for partial and high load/rpm readings?
I am using tunerpro.
Ignition map is at 4004 16x16  (Is it reading at part throttle and wot conditions?)
Fuel map is at 4104 16x16

Please confirm
« Last Edit: October 10, 2013, 05:47:18 pm by Alexiskayak_7 »

Offline Yoof

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Re: A weird day at the dyno
« Reply #6 on: October 10, 2013, 07:51:25 pm »
Tunerpro isn't a reliable source for information, Andy will be able to answer better, although I can tell you 7' timing will make a clear difference to power!

How are you measuring fuel flow?

The regulator is 3 bar, dependant on inlet manifold conditions fuel rail pressure (as measured on the end of the rail will vary) to maintain an injection pressure of 3 bar. So if manifold is in vacuum, rail pressure is <3bar, if manifold is boosting rail pressure needs to be >3bar

Wideband needs to be pre-cat! 

Offline Alexiskayak_7

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Re: A weird day at the dyno
« Reply #7 on: October 10, 2013, 11:06:33 pm »
Tunerpro isn't a reliable source for information, Andy will be able to answer better, although I can tell you 7' timing will make a clear difference to power!

How are you measuring fuel flow?

The regulator is 3 bar, dependant on inlet manifold conditions fuel rail pressure (as measured on the end of the rail will vary) to maintain an injection pressure of 3 bar. So if manifold is in vacuum, rail pressure is <3bar, if manifold is boosting rail pressure needs to be >3bar

Wideband needs to be pre-cat!  

Yoof, i added 7 degrees and i lost 1 hp how the hell is this possible???
The engine was not overheated, and i/c was relatively cool..
Can you please tell me so i can confirm a few map locations? such as ignition/fuel main, idle ignition,wot fuel (and if idoes exist wot ignition)  As i said, i wasn't able of data tracing..

I have a pro fuel preassure gauge that it has attached a fuel flow gauge
« Last Edit: October 10, 2013, 11:09:12 pm by Alexiskayak_7 »

Offline Yoof

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Re: A weird day at the dyno
« Reply #8 on: October 10, 2013, 11:21:10 pm »
What I'm saying is, I don't think you have added any ignition advance.

Map locations I don't know  :)

Wideband pre cat!

Offline Alexiskayak_7

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Re: A weird day at the dyno
« Reply #9 on: October 10, 2013, 11:49:57 pm »
What I'm saying is, I don't think you have added any ignition advance.

Map locations I don't know  :)

Wideband pre cat!

Ok... I will move pre cat the wideband sensor,

Can your brother give me some information about ignition maps?

Please guys, i need some help, to finish my final part of my final paper

Offline Andy

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Re: A weird day at the dyno
« Reply #10 on: October 11, 2013, 06:57:22 am »
Stick a timing light on the car to make sure that you're actually adding advance rather than taking it away.

Also be aware that 1-bit doesn't = 1° of advance.

Offline Alexiskayak_7

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Re: A weird day at the dyno
« Reply #11 on: October 11, 2013, 03:39:22 pm »
Stick a timing light on the car to make sure that you're actually adding advance rather than taking it away.

Also be aware that 1-bit doesn't = 1° of advance.

Yes Andy i know.. I don't remember right now, but there is a ignition formula (x* number)-number.
I will post the formula later when i get home, so you will confirm me.

I'll have to dig out my timing gun.

Andy, what adapter you use for data tracing? EVC or Grautec one?

Offline Alexiskayak_7

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Re: A weird day at the dyno
« Reply #12 on: October 11, 2013, 09:15:23 pm »
Andy, the ignition calculation formula i know, is: (X*-0.351563)+73.9. Am i correct?

Can i send you my xdf file so you see if there is something wrong with it please and giude me?

Also, while i am emulating i unplug the lamda sensor. Is there any other sensor i have to unplug?


Please i have to find what is going wrong and i fix it to make my final paper.