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Discussion Starter #1
Hey everyone.

Question for the guys with Unichips installed. Has anyone done a dyno run a couple of days / weeks after having the ECU installed and tuned?

I'm just curious because I just had one fitted and installed, and got some gains out of it. I did another power run 3 days later and all the power was missing. The mixtures were still right, but it was pretty much back to "baseline".

We reset the factory ECU and ran her up again, and she pulled the "modified" power figures again.

It was suspected that the car had a bad batch of fuel, or maybe some heat soak, or something to explain why the Nissan ECU had "learned" the way it had. Given my friend's experience with his S15 JR1 spec where the combined management would go weird after a couple of days, to the point where the power delivery would flat-spot and they had to abort power runs because it was running dangerously lean, its got me thinking.

To be honest, the car didn't feel any different between when I drove it away from the tuner's, and the morning I drove back there for the dyno day.
 

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did you went to the same Dyno? I'm n ot sure either. I heard about someone telling me that the ECU will return to the state of standard power.

But maybe i should have dyno my car as well to find out.

Cheers
Yun
 

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Alan:

Were those runs carried out on the same dyno? I don't think ECU will self learn to adjust to a piggy back system though..... I know this will happen in the PowerChip case (reflash)...

But to me, I didn't feel any loss of power though when I had the unichip....

cheers,

richie
 

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Alan

When APS fitted just the Unichip on my car (N/A) before the turbo's where fitted we did 3 power runs, on the day it was fitted, two weeks later and before the TT was fitted around 3 months later, the power figures were all around the same give or take a few kw's.

Cheers :cheers:
 

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Discussion Starter #5
Same dyno all times, same person doing it. 165rwkW baseline (in line with my 167.8rwkW run I did at a different dyno at the beginning of the year) and 179.9rwkW after tuning. Dyno Dynamics in Shootout mode, natch.

Everything was pretty much identical between the two days(ambient temperature was 1 degree off and relative humidity were within single digit difference), not enough to explain a 12rwkW drop to 165rwkW I got 3 days later.

The mixture hadn't changed, so that only left timing or a bad batch of fuel (my car only gets BP Ultimate so it wasn't a shift in RON per se). As I said, as soon as I had the ECU reset I pulled 182.1rwkW so I got my tuned power back when we removed everything the ECU had learnt over 3 days. Its weird. Its clearly not a "Unichip losing my tune" issue, it just seems like my ECU had a hissy fit.

Admittedly the guys didn't strap the car down to the dyno while tuning my car (and it was during the dyno day power runs), but after we reset the ECU and ran the equivalent power figure the car was strapped down at all times, once again removing another possible source of "error".

Before we discuss relative tuners, there was another 350Z at the dyno day with an APS catback, K&N panel filter and a Unichip (done by another tuner) that pulled 170.x rwkW (which seems low compared to what I got on a "fresh" tune), so it might not just be me.


I didn't feel a power drop during the week, but then I also wasn't driving the car mega hard that much. I'm wondering if this is the issue - how do you guys "commute" in your cars? Do you leave it in a middle gear around town, or aim for top gear?

I tend to hunt for the highest possible gear that will keep the car moving under lightish throttle. That means I'm in 6th gear at 60-70km/hr (which is what I do around town), and probably 4th at 50km/hr. I'm just wondering if I'm lugging the engine, and my OEM ECU is retarding the timing to compensate.


I was going to head back to do another power run and see how it was going, but unfortunately the guys were booked out. I might continue to drive the car like a granny until I can make a power run. If she needs another ECU reset I'll do it and then drive the car in whatever gear keeps it above 2000RPM, and run her up a week later to see if she "holds" the tune.
 

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Just a thought, my son works for Mercedes and when they know a demo is coming up for a customer who is after a fast sporty type of car they will take that car out and give it a hiding just before the demo, he says it because the ECU adapts to the way you drive, maybe our car tend to do this also, plus alot of the guys in the US have posted that they reset the ECU very two weeks?

Cheers
 

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Discussion Starter #8
Originally posted by db350z@Jun 16 2005, 09:16 AM
how you reset your car? Pull battery or using the Pedal reset?


My tuner has the OBD interface unit, so he plugged it in to the ECU and used the menu to do the reset.

How do you do a "pedal reset"?


I'm thinking, if that's the case, to find some way of doing a reset myself every time I head out for track work or whatever. :)
 

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it's very complicated to do scathing.

You can find it on DIY section guide in this forum.

You have to be Very precise in timing. like 3sec MEANS 3SEC
 

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I think our ECUs adapt to the way you drive, if you drive around the city and always in the highest gear possible (which is the way I drive 80% of the time as well) the cpu will optimise itself for that style of driving. I think it was found by AAM when they were doing dyno testing for their plenum spacer that they had to make 10+ pulls (speaking from memory, could be more or less) on the dyno before the car produced maximum power. So if you car starts loosing power, give it a good hiding and see if it feels faster.
 

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Discussion Starter #11
Just had the car power run again, and its still running like a dog. 164rwkW when I ran it on, with a much lower ambient temp.

Even with several ECU resets and minor fiddling with the timing, the best they could pull was a 168rwkW (173rwkW when they loosened the straps tying the car to the dyno down). The mixtures were spot on 13.6 for pretty much the entire power run.


From what I can see in the graphs, compared to my 182rwkW run the car's low-mid range is identical, but past a certain RPM (can't remember exactly what it is now, but 5500-6000RPM the power just falls away.

They suspect the car might be wheel spinning on the dyno up-top, but I'm not entirely convinced.


Anyway, I'm going to track the car this weekend at Wakefield, and then give them one more go. If its not working, I might see if Autotech can sort it out.
 

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ive taken the time to read this whole thread

and imo i think ur next step would be asking them to fit a new piggyback chip. Perhaps the chip itself is faulty and isnt overriding ur ECU. Sure its working just after tuning because the settings are freshly set, but they dont seem to be stored

what ur ECU is doing defeats the purpose of piggy backing it in the first place, and id be pissed, especially considering the price of these

just ask em to run a new chip and see what that does

its not ECU, it was working fine before u fitted the chip. Your driving style shouldnt affect a piggyback, which by my understanding doesnt allow the ECU to use its self learning function, but is always overriding it with its own settings
 

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Discussion Starter #13
We don't think its the Unichip either, though. We laptop'ed in yesterday and the tune's still there.

As I said, when you reset the factory ECU (the first time anyway) the combination ran perfectly.

The ECU is still "working fine", in that its learning. An ECU reset should have killed what it's learnt (with the data provided by the modified signals the Unichip passes on) but, clearly not. I'm kind of hoping its a bad batch of fuel.

I'm tracking the car on the weekend and dyno running it up next week. If its good again, its fine. Otherwise, we'll probably bypass the ECU and run her without. But yeah, I might see if I can try a second ECU.


Anyway, has anyone else dyno run their Unichip equipped cars a little while after install and tuning?
 

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Discussion Starter #15
OK, end to the saga (I hope).

After playing around with another customer's car and having a think about it, my tuner has finally worked out how to tune the Unichip for the Z33's ECU. It just requires a slightly different set of parameters than the other ECUs he's worked with.

So I did the tune, ran it up to 182rwkW. I took it back 2 weeks later, and I found that it was running in the high 160's, low 170's again.

After looking less than impressed....we ran it a couple more times. Rather than doing the ECU reset, we just kept running it (normally you do 3 power runs...I did about 10) and on the 8th or so I was making the numbers again.

When the ECU realised, from my repeated full-throttle-to-redline inputs, that I wanted power rather than economy......it gave it to me.


I still want to take my car to another tuner and power run on their dyno (as long as its a Dyno Dynamics with Shootout mode on, of course) and compare the numbers, but as long as they're within margin of error of each other I'll be happy.

Hopefully the saga is over.
 

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Originally posted by illz33@Sep 13 2005, 11:11 AM
The ECU has 3 timing maps.  It learns from how you drive.
[snapback]154760[/snapback]​



Gee, I wonder how the ECU reads my driving habits... Redline at every open sets of lights I find and then heaps of cruise control down highways.

Is there any way to tell it to abandon the stupid power saving mode and give me maximum power? I mean ****, if someone is all that worried about fuel they wouldn't buy a sports car would they?
 

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Discussion Starter #18
I believe it is possible. The ECU is flashable, so you can actually do tuning on it without using an interceptor.

Of course, if you have your ECU set to the most aggressive tune and something goes awry (bad batch of fuel, very hot or cold temperatures, etc), you may do damage to the engine.


With the way it is now, if I do track work I'll still get max power...I just have to full throttle the car a few times (which I can do on my out lap, so its not a major issue).

For country road runs, I can probably just knock it back into 2nd and rev it to redline a few times to wake the ECU up without having to achieve ludicrous speed, and then go enjoy myself.
 

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Discussion Starter #20
If you can do the reset at the track then it'll be good.

But if you're going to drive from, say, Melbourne CBD to Winton or Philip Island (I'm not entirely sure where Sandown is) at a reasonable rate, then chances are your ECU will settle into the economy map by the time you get there.

If anything, just warm the engine up before you head out, and then flat throttle to redline every straight you can during your out lap. That will hopefully warm your brakes and tyres up enough too, and you should be right by your first flying lap.
 
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