Interesting Findings after ProECU Tuning!

[vagthomas]

Very interesting findings after tuning (ProECU from ECUTEK) my GT86 and
a friend's of mine at the same day at the same dyno.

List of Mods
============

Mine: K&N Filter and TRD High Response Exhaust Muffler. Rest stock

Friend's: K&N Filter, HKS Resonated - Decat Front Pipe and Legamax Axleback. Rest Stock.

Tuning
======

Mine: Dyno test prior tuning showed 166 whp. After tuning we were at 173
whp and an increase of torque on an average of 0.7-0.8 kg within all RPM
range. Tuning not finished yet. With some further changes we expect to
gain 2-3 whp more.

Friend's: Dyno test prior tuning showed 155 whp (only)!! AFR was lean
within all RPM range (3% from target low, 14% from target mid, 23% from
target high). After MAF Rescaling, Fuel Trim optimisation (both closed and
opened loop), AFR Remapping, avanche, various other details that only my
tuner knows and without Touching VVT (yet..), the car went 169 whp and
gained 1.3 kg torque within all RPM band!! Basically, this is another car!!
That was correction of the system and not tuning!! Tuning though is not
finished yet. Expecting to get 5 whp more with some further changes as
my tuner advised.

Imortant detail: Both cars never tuned in the past. This was the first time!!

CONCLUSIONS
===========

This car's air and exhaust system is fully optimised from factory. The
replacement of front pipe with resonated de-cat HKS and axleback
Legamax most probably increased the vacuum in the cylinders (exhausts
flowing freely), therefore more air coming inside..air that could not be
handled by the stock tuning, leading to lean AFRs. The percentage
differences from target noticed high are so big (23% !! ) that someone
could even say is dangerous, in case you drive the car always on the
limit!

[Tor]

Did you check your friends car for mechanical defects? Changing things after the header shouldn't make such a big difference.

[vagthomas]

Originally Posted by Tor

Did you check your friends car for mechanical defects? Changing things after the header shouldn't make such a big difference.

That is what I was expecting also. However, everything was checked. No any mechanical problem noticed.

[Tor]

Originally Posted by vagthomas

That is what I was expecting also. However, everything was checked. No any mechanical problem noticed.

Well something must be wrong, because you don't get 23% fuel error from header back exhaust. I should have phrased that more clearly.

It doesn't have to be something that is outright broken. E.g. you said he uses a KN filter which is oiled. I don't know if excess oil could mess up the MAF sensor readings like that, but I would definitively take it out and clean it. I suppose you already checked both intake and exhaust for leaks.

Something is amiss.

[vagthomas]

Originally Posted by Tor

Well something must be wrong, because you don't get 23% fuel error from header back exhaust. I should have phrased that more clearly.

It doesn't have to be something that is outright broken. E.g. you said he uses a KN filter which is oiled. I don't know if excess oil could mess up the MAF sensor readings like that, but I would definitively take it out and clean it. I suppose you already checked both intake and exhaust for leaks.

Something is amiss.

O2 Sensor was confirmed with external one. MAF was calibrated..Curve was completely out of logic. There are no any leaks, anywhere. Air and exhaust system were thoroughly checked. With MAF calibration and fuel trim optimisation the car went 166 whp (as was mine initially). I do not think that something is wrong. Engine is running much more smoothly now.

Any further ideas for checkings would be most welcome!

[-Willis-86touge]

Probably because his front pipe wasn’t creating the backpressure a stock system has, inturn computer compensation was inaccurate!

[Detroiter]

Originally Posted by -Willis-86touge

Probably because his front pipe wasn’t creating the backpressure a stock system has, inturn computer compensation was inaccurate!

No, the front pipe will not cause anywhere near that much a difference. There is something wrong (Vacuum leak, exhaust leak, MAF dirty, etc).

[Tor]

Originally Posted by vagthomas

O2 Sensor was confirmed with external one. MAF was calibrated..Curve was completely out of logic. There are no any leaks, anywhere. Air and exhaust system were thoroughly checked. With MAF calibration and fuel trim optimisation the car went 166 whp (as was mine initially). I do not think that something is wrong. Engine is running much more smoothly now.

Any further ideas for checkings would be most welcome!

There are a number of places you could have leaks from the intake. E.g. the crank case vent hoses. Did you check those as well?

I would unscrew the MAF sensor take it out and clean it.

And I would look for a tuner that has experience with the FA20. There are lots of reputable remote tuners if you don't have anyone where you live. Dyno tuning a stock car is really a waste of money. And especially so if the tuner doesn't know the engine.

Originally Posted by -Willis-86touge

Probably because his front pipe wasn’t creating the backpressure a stock system has, inturn computer compensation was inaccurate!

A 4 stoke engine doesn't require back pressure. The less the better. Anyway, the biggest restriction on the GT86 is in the header.

A 2 stroke does need it because it has ports instead of valves. So it needs back pressure to keep the fresh charge in the combustion chamber.

[Tokay444]

Originally Posted by vagthomas

Very interesting findings after tuning (ProECU from ECUTEK) my GT86 and
a friend's of mine at the same day at the same dyno.

List of Mods
============

Mine: K&N Filter and TRD High Response Exhaust Muffler. Rest stock

Friend's: K&N Filter, HKS Resonated - Decat Front Pipe and Legamax Axleback. Rest Stock.

Tuning
======

Mine: Dyno test prior tuning showed 166 whp. After tuning we were at 173
whp and an increase of torque on an average of 0.7-0.8 kg within all RPM
range. Tuning not finished yet. With some further changes we expect to
gain 2-3 whp more.

Friend's: Dyno test prior tuning showed 155 whp (only)!! AFR was lean
within all RPM range (3% from target low, 14% from target mid, 23% from
target high). After MAF Rescaling, Fuel Trim optimisation (both closed and
opened loop), AFR Remapping, avanche, various other details that only my
tuner knows and without Touching VVT (yet..), the car went 169 whp and
gained 1.3 kg torque within all RPM band!! Basically, this is another car!!
That was correction of the system and not tuning!! Tuning though is not
finished yet. Expecting to get 5 whp more with some further changes as
my tuner advised.

Imortant detail: Both cars never tuned in the past. This was the first time!!

CONCLUSIONS
===========

This car's air and exhaust system is fully optimised from factory. The
replacement of front pipe with resonated de-cat HKS and axleback
Legamax most probably increased the vacuum in the cylinders (exhausts
flowing freely), therefore more air coming inside..air that could not be
handled by the stock tuning, leading to lean AFRs. The percentage
differences from target noticed high are so big (23% !! ) that someone
could even say is dangerous, in case you drive the car always on the
limit!

The car has a MAF sensor. It knows exactly how much air is coming in, regardless of how efficient the cylinder scavenging is. The tuner has likely now tuned for a leak.

[vagthomas]

Originally Posted by Tor

There are a number of places you could have leaks from the intake. E.g. the crank case vent hoses. Did you check those as well?

I would unscrew the MAF sensor take it out and clean it.

And I would look for a tuner that has experience with the FA20. There are lots of reputable remote tuners if you don't have anyone where you live. Dyno tuning a stock car is really a waste of money. And especially so if the tuner doesn't know the engine.

MAF Sensor is perfect and clean. There are no any leakages anywhere.
The car runs much more smoothly. I cannot be more clear on that.

On the other hand, if MAF or O2 sensor have problem, how could all
measurements be verified with external O2 sensor?

ECUTEK manual is very detailed. I have read it all! All that you need for
our engine is there! A good engineer with both good theoretical and
practical background (I am a mechanical Engineer myself) can do many
things on this engine. And we did!
Personally, the almost 1 kg of kilo within all RPM band is obvious and I feel it as another car while is more economic by 0.1-0.2 lt/100 km.

[Tokay444]

Was a boost leak test performed?

[steve99]

Originally Posted by vagthomas

MAF Sensor is perfect and clean. There are no any leakages anywhere.
The car runs much more smoothly. I cannot be more clear on that.

On the other hand, if MAF or O2 sensor have problem, how could all
measurements be verified with external O2 sensor?

ECUTEK manual is very detailed. I have read it all! All that you need for
our engine is there! A good engineer with both good theoretical and
practical background (I am a mechanical Engineer myself) can do many
things on this engine. And we did!
Personally, the almost 1 kg of kilo within all RPM band is obvious and I feel it as another car while is more economic by 0.1-0.2 lt/100 km.

Tail pipe o2 sensors will read a bit different to the o2 sensor right near the exhaust ports. It will be further "off" due to exhaust passing through catalytic converters. in general tail pipe will read leaner than an o2 sensor at exhaust ports, can be a considerable difference 0.5 or more afr.


all the tunes from 2012-2016 are pretty well the same for any countly and auto/manual (for power).


take a look at the MAF scaling from your original stock rom and from the tuned roms.


If you find big descrepencies in those scales with stock intake components then you likely have a maf sensor that's "off" or outside the normal tolerance band.


Ive seen some 8% or so off but never 20% like you found seems quite odd.


If you have compensated for a maf sensor issue with large cange to maf scaling you will see same afr.