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Gtir Motorsport club » Tech room » Ecu related section » Standard Pulsar vs Sunny ECUs

Standard Pulsar vs Sunny ECUs

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1 Standard Pulsar vs Sunny ECUs on 9th October 2013, 8:57 am

watoga

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ecu technician
ecu technician
Howdy folks,

A few people have asked me about the differences between the standard Pulsar and Sunny GTiR maps. I mentioned before that the Sunny maps are a lot more conservative, but I wasn't able to provide any "hard evidence" to support this. For this post, I will only concentrate on the fuel and timing maps for normal operating conditions (i.e. not including 'knock' maps which are switched to automatically when the sensors detect knock). I will break up the information into "fuel" and "timing" sections to help make it easier to digest. Enjoy!

FUEL MAPS:

What I've done is download the fuel maps for both the Pulsar and Sunny models, and compute the Air/Fuel ratios that the ECU is trying to achieve for a variety of engine RPMs and loads. Bare in mind that the stoichiometric ratio for combustion is around 14.7:1, which gives the most efficient burn of the fuel in the combustion chamber. During idle (and indeed most low-load/low-RPM scenarios) the engine tries to achieve this ratio by forcing a closed loop with the stock lambda sensor. However, once the engine load increases and the RPMs rise, it makes sense to add a little extra fuel to combat knock, which can result in catastrophic failure of your engine if not eliminated. Unfortunately, the standard maps are VERY conservative. Below is the standard Pulsar fuel map:



You will see that at high load and high RPM values, the A/F ratio that is trying to be achieved is around 10. This is VERY conservative. It gets even worse when you look at the Sunny map:



Here, the Sunny ECU is trying to hit A/F ratios of around 9!!!!!!!! This is drastic over-fuelling, especially for a stock car. Also, notice that the maps are not particularly smooth. The right panels of both images show a 3D plot of the fuel maps, and you'll see that there are lots of bumps and spikes, which tend to make the transition on to boost quite poor. Even by smoothing these bumps out the car becomes a little more pleasant to drive, but the real benefits arise once the fuelling is reduced for high RPM and high load values. It is commonly assumed that an A/F ratio of around 11-12 is good for high RPM and high load areas of the map.

TIMING MAPS:

OK, now I've downloaded the timing maps from both the standard Sunny GTiR and Pulsar GTiR ECUs. First up we have the standard Pulsar GTiR timing:



The values listed here represent the angle BTDC (before top dead centre) when the spark plug is fired to start the burn process. Top dead centre occurs when the piston is closest to the cylinder head on it's compression stroke (i.e. just before it starts to move downwards again on its 'power' stroke). If all of the fuel in the combustion chamber burned immediately upon the spark plug firing, then you would want to fire the spark plug approximately 20 degrees ATDC (after top dead centre). This way, the piston would already be starting its downward motion and the immediate burn of the fuel would cause maximum acceleration of the piston on its power stroke (hence producing maximum torque!). However, this is an ideal scenario, and not one which we encounter in a real internal combustion engine Sad Instead, the fuel does not burn immediately, and unfortunately takes a while before all of the fuel vapour has been completely ignited. As a result, we have to start the ignition process before the piston has reached the top of its compression stroke (i.e. a number of degrees BTDC), so that all the fuel has been burned a short time after the piston reaches TDC, thus providing optimum torque readings. This is called "ignition advance" because you are commencing the burn before (i.e. in 'advance' of) the piston reaches TDC.

Have a look at the ignition timing when the Pulsar GTiR engine is at idle with no load. You will see that the ignition timing here is "20", which refers to 20 degrees BTDC. This is why people use a timing gun to check that the idle ignition is around 20 degrees BTDC in order for it to be in sync with what the ECU wants. As engine RPM increases, the ignition timing will need to become more advanced (i.e. a larger angle BTDC) so that the fuel vapour has the correct amount of time to fully burn. This is quite simple to understand since as the engine speed (RPM) increases, the time available to burn the mixture decreases (more revolutions occurring each second) but the burning process itself proceeds at the same speed. Therefore, the ignition needs to be started earlier as the RPM increases in order to complete combustion in time for the start of the 'power' stroke shortly after TDC. Take a look at the load column (16): at idle the ignition timing is 20 degrees BTDC, rising to 50 degrees BTDC at 6800 RPM.

The problem arises when you start dealing with high engine loads. These could be an effect of hot engine temperatures, high boost levels, or even something simple like driving up a hill. Under these conditions the ignition timing is also dependent on the specific load applied to the engine. Here, more load (i.e. at full throttle) will result in a larger throttle opening (supplying more air into the cylinders), ultimately allowing the fuel vapour to burn more easily and in a faster time. Under these conditions, less ignition advance is required since the burn process may be more efficient due to efficient filling of the combustion chambers with air. This is called "ignition retardation" because you are commencing the burn later (i.e. closer to TDC) in the engine cycle. Take a look at the RPM row for (6400): with minimal engine load the ignition timing is 50 degrees BTDC, decreasing to 26 degrees BTDC at high load values.

Also, retarding the ignition with higher engine loads is a good way to help prevent knock. At higher engine loads, the engine is likely to be physically hotter, and this may assist the burn process complete in a very rapid time. If you kept the ignition timing 50 degrees BTDC and the burn process occurred very rapidly, then you may find that the burn process has completed before the 'power' stroke has even started. This means that the forces created by the burning fuel push against the rising piston (remember, if the piston is BTDC it will still be on its compression stroke), thus slowing it down and creating no assistance once the piston begins its downward motion of the 'power' stroke. Best-case scenario will result in reduced power (remember highest power results when the burn process completes shortly into the 'power' stroke, i.e. ATDC). Worst-case scenario is complete engine destruction as the forces may be so strong that substantial 'knock' or 'pinking' occurs, causing cylinder and/or piston damage. Therefore, as a safety factor, most ECUs incorporate very safe timing angles at high engine loads. Take a look at the point on the timing where an engine may be coming on to boost with the throttle fully open (i.e. 3200 RPM and load 86): here the ignition timing is 16 degrees BTDC - a very conservative timing to insure that no knock/pinking occurs - basically putting engine longevity ahead of absolute power.

Now take a look at the standard Sunny GTiR timing map:



You will immediately see that the base timing (i.e. idle with no engine load) is identical to that of the Pulsar GTiR. This is why you can set your timing with a timing gun to approximately 20 degrees whether-or-not you have a Sunny or Pulsar. You will also notice that almost all low-load areas are identical to the Pulsar GTiR timing map, even up to the engine load column (54). However, once you move into higher engine loads (i.e. load columns 54-86) you will see that the Sunny GTiR timing map makes the timing a lot more retarded (i.e. closer to TDC) compared with the Pulsar GTiR timing map. You can see that during the on-boost RPM at high loads (i.e. 4050 RPM and load 86) the Sunny GTiR ignition timing is 9 degrees BTDC! This is few degrees more retardation than the Pulsar GTiR timing map, resulting in much more protection against knock/pinking, but at the expense of reduced power/torque. By looking at both the fuel and timing maps, you'll be able to see that the Sunny GTiR maps overfuel and retard ignition timing when compared to their Pulsar GTiR counterparts. Perhaps this was done to combat lower octane fuel found in Europe, but it unfortunately results in grossly conservative fuel/timing maps.

I hope this helps to shine a little information on the standard Sunny/Pulsar GTiR fuel+timing maps.
Cheers,
Dave



Last edited by watoga on 23rd October 2013, 8:30 am; edited 1 time in total

http://star.pst.qub.ac.uk/~dbj

2 Re: Standard Pulsar vs Sunny ECUs on 9th October 2013, 10:14 am

nomad

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Thanks dave it makes it alot simple seeing it in a graph .....when i get chance il see if i can send you my ecu ...would be intresting to see how it fares against either maps ....if its better or even worse .....

3 Re: Standard Pulsar vs Sunny ECUs on 9th October 2013, 10:19 am

watoga

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ecu technician
@nomad wrote:when i get chance il see if i can send you my ecu ...would be intresting to see how it fares against either maps ....if its better or even worse .....
No problem at all. Some chipped ECUs either take the simple approach of modifying the fueling/timing to allow extra boost/power, or they take the more professional approach and adjust the load scales so the ECU can understand why there is more engine load (ie more boost) and compensate accordingly. I'd be happy to help display/compare your maps to standard OE ones.

Cheers,
Dave

http://star.pst.qub.ac.uk/~dbj

4 Re: Standard Pulsar vs Sunny ECUs on 9th October 2013, 11:01 am

r called jay


Great write up Dave, keeping things simple and easy to understand.

That's going to help many members on here have a clearer idea of how the ecu works.

5 Re: Standard Pulsar vs Sunny ECUs on 9th October 2013, 11:13 am

GTI-R US

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Management
Management
yep good write up dave and simple enough to get your head round

ive recently obtained a mines ecu which im in no mad panic to sell
do you want me to send that out to you so you can take a look at the map on it to compare with stock?
I know theres a fair few people that would like to take a look at the fuelling etc on one of these and also the ignition the units run

http://www.gti-r-us.co.uk www.force500.com

6 Re: Standard Pulsar vs Sunny ECUs on 9th October 2013, 2:07 pm

watoga

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ecu technician
@GTI-R US wrote:yep good write up dave and simple enough to get your head round
ive recently obtained a mines ecu which im in no mad panic to sell
do you want me to send that out to you so you can take a look at the map on it to compare with stock?
I know theres a fair few people that would like to take a look at the fuelling etc on one of these and also the ignition the units run
Hi Bob,

Yes, I'd also be keen to compare the Mines maps to standard. I'd be able to compare not just the fueling, but also the timing, RPM limits, fuel cuts, etc. Would be a very useful study for most people, since a decent number of the Mines ECUs are floating about.

One issue is that I'm currently moving house, so won't be able to plug it into my diagnostic computer until the start of November (just over 3 weeks away now). If you still have it in 3 weeks, then absolutely! It would only take 2-3 days to get all the information and then I could post it straight back to you and get the comparisons put up on this site.

Cheers,
Dave

http://star.pst.qub.ac.uk/~dbj

7 Re: Standard Pulsar vs Sunny ECUs on 9th October 2013, 5:10 pm

pulsarmoley

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Can you remind me of what fuel cut is please Dave, also on the graphs, is the load number random increase or is that in a % of the tps? Cheers Pete.

8 Re: Standard Pulsar vs Sunny ECUs on 9th October 2013, 7:49 pm

fred05

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french connection
french connection
really interesting! thanks dave!

what is the unit of the load? no units? is it just a ratio?

9 Re: Standard Pulsar vs Sunny ECUs on 10th October 2013, 10:26 am

watoga

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ecu technician
ecu technician
@pulsarmoley wrote:is the load number random increase or is that in a % of the tps? Cheers Pete.
Pete,

The TPS values typically refer to the "Throttle Position Sensor", which are not used in the calculation of the ECU load scale. The actual load scale is calculated using the TP values, which correspond to the "Theoretical Pulsewidth". In a nutshell, the ECU calculates the TP values using the equation:

Theoretical Pulsewidth (TP) = MAF Lookup (essentially the airflow through the MAF) x Injection multiplier / RPM

This gives a value for the TP, which is then used to index the timing/fueling values as an input for the engine. You can imagine (from the equation above) that more airflow and less RPMs will give you a high TP value, and hence more "engine load". You can actually calculate (for example) what the actual fueling pulsewidth will be given a particular TP value:

Injection Pulsewidth = Fuel table [particular RPM, TP value] + Injector Latency + Various enrichments (which may correspond to different real-world corrections such as temperature)

It is important to remember that the load values (ie TP values) do not directly relate to vacuum/boost levels. However, these TP scales need to be updated depending on the boost you are running since more boost will result in higher loads on the engine. You can imagine that if you increase the boost, the airflow will increase, so the maximum TP value will also increase (since it's proportional to the MAF lookup). If you run huge boost and do not increase the TP scales, then the load value will max out early on when you come on to boost, resulting in the engine not being fed proper fuel/timing values for the high load levels you are running. Ideally you want the engines actual maximum load to correspond to the right-hand column of the fuel maps above. This will insure that the entire load range (idle to maximum boost) is contained within the fuel/timing maps.

Hope this helps a little,
Dave

http://star.pst.qub.ac.uk/~dbj

10 Re: Standard Pulsar vs Sunny ECUs on 10th October 2013, 10:40 am

watoga

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ecu technician
@fred05 wrote:what is the unit of the load? no units? is it just a ratio?
Fred,

The Nissan ECUs have 16 spaces, with each space corresponding to a particular load value. As I mentioned in my previous post, running high boost will result in higher engine loads. So to compensate, you have to adjust the uppermost values of the default 16-space TP scales. For example, look at the following TP scales:



On the lefthand side we see a standard ECU load table. Idle corresponds to the first column, and a TP value of "8". Maximum load (perhaps at maximum boost and low RPMs) corresponds to a TP value of "80". However, if you now up the boost the actual TP value you are reaching may be 115 (remember, determined from MAF airflow and RPMs), but unfortunately your load scales only measure up to 80. This is not good as even if you have upgraded injectors, etc., your ECU will max out at a load of "80" and thus not be fueling/timing your engine properly as a result of the extra load which it cannot "see". To get around this problem, we can tell your ECU that it should now expect more load (due to the extra boost). In the righthand side, we can see that the TP values from column 10 onwards have been increased substantially. The lower load columns are left standard since these will correspond to low-boost off-load times. Now your ECU can handle the extra load, while still being able to handle off-boost situations with ease. Remember, the load values measured simply tell your ECU what columns of the fuel/timing tables to access. It is therefore a good idea that the maximum load your engine will ever experience just pushes it into the final column, and thus the final column in the fueling/timing tables.

Hope this helps,
Dave

http://star.pst.qub.ac.uk/~dbj

11 Re: Standard Pulsar vs Sunny ECUs on 10th October 2013, 5:03 pm

pulsarmoley

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Thanks for the info Dave. Can the closed loop part of the ECU be adjusted then? I ask as my turbo makes boost from approx 1200rpm and on my RR graph it doesn't go onto the rich side until about 2700rpm?

12 Re: Standard Pulsar vs Sunny ECUs on 10th October 2013, 7:32 pm

watoga

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ecu technician
ecu technician
@pulsarmoley wrote:Thanks for the info Dave. Can the closed loop part of the ECU be adjusted then? I ask as my turbo makes boost from approx 1200rpm and on my RR graph it doesn't go onto the rich side until about 2700rpm?
Absolutely. On the fuel maps there is simply a toggle which can be set as on or off, depending on whether you want the ECU to try and force a closed loop. If you look at the fuel maps displayed in the first post, the light blue regions (near the lower-left corner) are those locations (RPM and load) where the ECU tries to force a closed loop. If you are making boost very early, then you could lower the RPM/load limits where the closed loop is discarded.

Cheers,
Dave

http://star.pst.qub.ac.uk/~dbj

13 Re: Standard Pulsar vs Sunny ECUs on 11th October 2013, 7:19 pm

weblizzer




Okay this is the fuel map from the base map bin file that i got from Nistune rom pack. Just wondering on how does this value works? like if you wish to adjust can you just change the values? This is on the open loop. I open it on tunerpro.

14 Re: Standard Pulsar vs Sunny ECUs on 11th October 2013, 9:01 pm

watoga

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ecu technician
ecu technician
@weblizzer wrote:
Okay this is the fuel map from the base map bin file that i got from Nistune rom pack. Just wondering on how does this value works? like if you wish to adjust can you just change the values? This is on the open loop. I open it on tunerpro.
So these are the raw values. Values that are over 192 represent parts of the fuel map where the ECU tries to force a closed loop with the lambda sensor. If you subtract 192 from these (in your head) you'll see what the fuel values actually are. If you actually subtract 192 from the values in those boxes you'll remove the closed-loop functionality and the ECU will not use the lambda sensor in these low RPM/load regions. You can simply change the values, then reburn them to your ECU to make the changes permanent.

Cheers,
Dave

http://star.pst.qub.ac.uk/~dbj

15 Re: Standard Pulsar vs Sunny ECUs on 12th October 2013, 11:58 am

GTI-R US

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Management
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forgive me for sounding a bit dim dave but I always thought that the tps was a variable resistor (similar to fuel gauge) and the ecu took the reading from varying scales to determine how far the throttle was open, then info from maf and all the other relevant sensors such as knock values, wastegate duty etc were used to gauge fuelling under load by altering injector pulsewidth

when you get a little time would you mind explaining it a little further ie what each individual item does exactly and how these sensors actually work with regard to mapping an engine!

ive always had the rough jist of it but do not fully understand lets say with regard to how much ignition you would add at a given point in the map to obtain ultimate burn without compromising engine safety with over or under fuelling.

and yes I will keep the mines for you to get some readings from as it seems no one has actually put the info up from one of these units before and I would 'for one' like to see how ignition and fuelling compares to stock map

http://www.gti-r-us.co.uk www.force500.com

16 Re: Standard Pulsar vs Sunny ECUs on 12th October 2013, 4:00 pm

watoga

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ecu technician
ecu technician
@GTI-R US wrote:forgive me for sounding a bit dim dave but I always thought that the tps was a variable resistor (similar to fuel gauge) and the ecu took the reading from varying scales to determine how far the throttle was open, then info from maf and all the other relevant sensors such as knock values, wastegate duty etc were used to gauge fuelling under load by altering injector pulsewidth

when you get a little time would you mind explaining it a little further ie what each individual item does exactly and how these sensors actually work with regard to mapping an engine!

ive always had the rough jist of it but do not fully understand lets say with regard to how much ignition you would add at a given point in the map to obtain ultimate burn without compromising engine safety with over or under fuelling.

and yes I will keep the mines for you to get some readings from as it seems no one has actually put the info up from one of these units before and I would 'for one' like to see how ignition and fuelling compares to stock map
Hi Bob,

In reality, the TPS does very little during normal operating conditions. The TPS signal is used as a small factor when determining the actual injector pulsewidth (see the equation above for the pulsewidth, where this will come under "various enrichments", and in particular is related to the "acceleration enrichment"). But overall, the TPS signal will not affect what part of the map is accessed, nor will it have a dominant role in determining the overall fuel injected. However, when the ECU detects the throttle is closed (via the TPS sensor), then this will affect certain things such as overrun adjustments (such as a fuel cut to try and conserve fuel when decelerating in gear with the throttle closed), but normally the TPS plays a small part in the running of the engine. I think (perhaps compared to new performance Nissans, like your GTR) the GTiR ECUs operate on a relatively premative scheme, with very little factors used when determining the correct fuel/timing maps. I'll post up some information on the various sensors once I get a spare minute. I'll also try to show the various enrichment tables which may help quantify what I'm saying.

In terms of ignition, I've always been recommended a particular process. This process basically involves adding 2 degrees of timing to the high-load areas, then doing a dyno run to measure the torque. The torque will increase by a certain margain (say for example 5%). Then another 2 degrees of timing is added, with another dyno run made. The torque will increase by another amount (say another 5%). This process is repeated until the torque increase no longer equals the expected amount (say it only increases by 2% instead of the expected 5%). This means you are getting close to the knock limit. Typically the timing would be reduced by 2% to provide a safe value which still allows for uncertainties such as poor fuel and/or high engine temperatures. This is the recommended way to build a solid timing map. I'm sure others will have different methods to share.

Hope this helps a little.
Cheers,
Dave

http://star.pst.qub.ac.uk/~dbj

17 Re: Standard Pulsar vs Sunny ECUs on 12th October 2013, 4:22 pm

GTI-R US

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Management
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yep thanks dave that clears that bit up

some of it is a bit hard to get your head round without actually being shown what to do and im not the brightest star in the sky with regard to stuff like this.

il certainly be getting a little more involved with it though as its interesting and I would like to learn more about the parameter readings and everything else regarding, even if just to learn a bit about the map that's loaded onto car and where things can be improved if at all possible

http://www.gti-r-us.co.uk www.force500.com

18 Re: Standard Pulsar vs Sunny ECUs on 12th October 2013, 7:53 pm

weblizzer


hi dave thanks for your reply... it's very informative.. anyway just a thought. I install my innovate afr.

when i do test i got 10.4 on WOT @.5 bar ... btw, i'm using a stock sunny/ jdm ecu.. so means it's way too rich? would it be compensate if i will increase around .7?

tnx.

19 Re: Standard Pulsar vs Sunny ECUs on 12th October 2013, 9:17 pm

watoga

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ecu technician
ecu technician
@weblizzer wrote:hi dave thanks for your reply... it's very informative.. anyway just a thought. I install my innovate afr.

when i do test i got 10.4 on WOT @.5 bar ... btw, i'm using a stock sunny/ jdm ecu.. so means it's way too rich? would it be compensate if i will  increase around .7?

tnx.
Hi,

Yes, it is normally assumed that an 11-12 air/fuel ratio is optimal at WOT. You could reduce the amount of fuel slightly (to raise your air/fuel ratio from 10.4), but please keep a close eye on you air/fuel ratios to make sure they do not lean out too much. Are you running high octane fuel? Also, listen/monitor for any signs of knock (particularly if you are tweeking the ignition map as well) as that will keep your engine safe. Also pay particular attention to the locations of the map where you just come on boost, since any spikes here will affect your fuel mixtures significantly.

Good luck, be patient with minor changes each time, and let us know how you get on.
Cheers,
Dave

http://star.pst.qub.ac.uk/~dbj

20 Re: Standard Pulsar vs Sunny ECUs on 21st October 2013, 2:32 pm

watoga

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ecu technician
ecu technician
OK, just to keep people up-to-date, I'm preparing some graphs and text to compare the Sunny vs Pulsar timing maps. Just like I did for the fuel maps, I will compare the timing values over a range of engine loads and speeds to show just how conservative the Sunny map is compared to the Pulsar one. I'll hopefully be able to post this in the next couple of days.

Then I'll show how some people use the deceleration tables to get pops, bangs, and flames out of their exhaust on the overrun......... Stay tuned Cool 

Thanks,
Dave

http://star.pst.qub.ac.uk/~dbj

21 Re: Standard Pulsar vs Sunny ECUs on 21st October 2013, 3:27 pm

fred05

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french connection
french connection
yeaaaah, mine do pops and bangs, i really love that!!!!

22 Re: Standard Pulsar vs Sunny ECUs on 21st October 2013, 3:57 pm

GTI-R US

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Management
Management
yep great dave will be interesting to see whats been done and how it could affect the fuelling

http://www.gti-r-us.co.uk www.force500.com

23 Re: Standard Pulsar vs Sunny ECUs on 22nd October 2013, 1:05 pm

watoga

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ecu technician
ecu technician
*** Note this post originally contained information on the timing maps, but to make things easier to follow I've place the timing information at the end of the very first post (i.e. immediately after the fuel map discussion) ***

Cheers,
Dave



Last edited by watoga on 23rd October 2013, 8:31 am; edited 1 time in total

http://star.pst.qub.ac.uk/~dbj

24 Re: Standard Pulsar vs Sunny ECUs on 22nd October 2013, 2:37 pm

gtirx2

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That is a very good read, great write up mate.

25 Re: Standard Pulsar vs Sunny ECUs on 22nd October 2013, 3:47 pm

GTI-R US

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excellent write up dave thanks for taking the time to do this for us cheers 

definitely clears a few things up in my mind

http://www.gti-r-us.co.uk www.force500.com

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