So as mentioned before, I got myself a ve ssv ute loaded with plenty of mods, unfortunately during the previous ownership someone drilled a large 6mm hole in the throttle blade.

Now if your wondering why they did this it’s pretty simple. It was done as a quick fix, laziness or they just didn’t know how to tune the Electronic Throttle & idle control system properly for this camshaft.

The main reason why you would drill a hole in the blade of any car is it effectively allows more air straight into the manifold when the factory bypass won’t flow enough air, or the blade is movement limited.

Now that’s okay to do on the cable operated throttle bodies & even on some very large camshafts you will have no choice but to drill a hole even on a ETC controlled motor, BUT in this case for this particular engine combo it was not required at all. As you often end up creating more problems then you attempt to solve such as; exaggerated lumpy idles, cruise control effect when you back off the throttle, hanging idles when coming down through the revs or to a stop.

To give you an example, below is a screenshot log of my car in-gear with the original idle tune and 6mm hole throttle body from above. (Click to enlarge)

As can be seen in the log there are 2 things that stand out:
1) Large swing in timing & idle rpm
2) High manifold vacuum which leads to poor braking

This is because the ecu is commanding a set idle speed and is than constantly over-shooting then under-shooting it. To fix this the ecu can do 2 things, adjust the timing (reacts quicker) or adjust the tb position (slower reacting) to meet the requested idle speed.

I won’t go into the technical details on how this is fixed, because to most people it wont mean anything but needless to say once a throttle blade with no hole and the idle parameters are setup correctly, the idle ends up being a lot smoother without the excessively noticeable camshaft lope and more vacuum for braking. The results would be the same even with a hole, but only if your tuner has calibrated the relevant tables to compensate for the additional airflow.

I had someone from a local car forum I’m on ask me about taking a look at his civic which he races regularly at Wanneroo Raceway as he wasn’t happy with a recent tune-up after a cam swap.

So with some spare time on my hands today we put it on the dyno. What was apparent straight away was the car was running extremely rich from idle until “VTEC” was activated around 6000k rpm & was lacking in power at all rpm’s below.

Considering this is the first time I’ve ever done one of these motors/ecu combo’s & it only took a few short hours to sort out. We got some pretty good gains below the vtec change over point along with gains in fuel economy both at wide open throttle and normal throttle points.

I spent some more time this weekend playing with the Cruze on the dyno again after installing a de-cat pipe along with the bigger injectors for running E85.
With the new pipe in, exhaust note & noise is still the same. At least within the car.

Tuning wise it seems to have helped improve the power in the top end from fading, even though boost is still dropping away.

As always a dyno graph tells it like it is.

With the LSM11 wideband sensors becoming quite costly and very outdated compared to the latest Bosch LSU 4.9 sensors, I decided to replace the factory Dyno Dynamics (Autronic) wideband with an ALM-LED that has both analog and serial output (along with a couple of inputs if required).

As such with a bit of digging and tracing the wires, the below information might come in handy for some one else looking to do the same. I simply made up a male DB9 connector to match the existing autronic cable from the dyno. I originally planned to replace the round connector at the dyno controller, but after ordering the wrong “AMP” connector size I went with the DB9 connector instead.

Original Autronic Wideband Connector Wiring:
Cable Colour – DB9 PIN # – Round Connector Pin # – Usage

Green – Pin 1,2 DB9 – Pin 1 – Power Ground

Brown – Pin 4 DB9 – Pin 4 – Sensor Ground

Red – Pin 5 DB9 – Pin 5 – 0-5V from Wideband to Dyno

Yellow – Pin 8 DB9 – Pin 8 – 0-1V output

White – Pin 6/7 DB9 – Pin 6 – 16v Supply from Dyno

Dyno software will either need to modified to suite a 10-20afr range if that’s what your wideband uses by default or you need to program your widebands analog output to the standard 10-30 afr range the Autronic uses.

With the new wideband sensor being able to read much leaner mixtures, the lambda value on the led display is pretty high. But testing on a car proved to be dead on accurate from the digital to analog lambda value.

With Mon5ta currently getting an over due freshen up after years of abuse to the driveline. Owner/Driver Matt has decided to debut his new blown setup on another car.

With another stock ls1 motor with a suspected vcm-7 camshaft (232/234@112) and 6/71 blower setup by Nelg’s Alloy Mods slid into place of a previous factory v6 vy commodore. We finally hit the dyno for an initial tune up today and too see what bugs might be thrown at us on the new combo.

Apart from a stuffed wideband cable to delay tuning for 30 minutes, everything went rather smoothly with an initial power run of 470rwhp with a very safe 9 degrees of timing on E85 & 0.82 lambda thanks to it’s maximum 7.5psi of boost.

With a couple of tuning adjustments to fuel & timing, it was decided to leave the car at a maximum of 520rwhp & 6300rpm limiter for it’s initial tune up.

We will more than likely look into a water/meth injection kit to assist with keeping the air temps in check for long duration burnout’s rather then running injectors within the hat.

With over 16k km’s on the motor now, I thought I would have do a quick check of the power output to see how it’s going. I also flashed in the original factory tune so as to have a true comparison with the same temperature/day.

As can be seen, the tune is still making a solid 30whp more today than the factory tune and a solid 310lb more of tractive effort to the wheels below 3800rpm.

While probably not in the right order in the tuning blog I thought it relevant to post the results from my injector upgrade on the Cruze running standard 98 octane petrol.

The main reason for tuning the bigger injectors on 98 is I’m hoping to find the relevant pin on the ecu that will allow for flex fuel support, What this means is that I can fill up the car with any amount of ethanol or petrol and the ECU will automatically adjust the fuelling to suit, But in order to do so I need a baseline fuel & timing map to start with.

The 125hp reading is from the factory injectors & tune., 150whp+ are injectors & tune.

Next job is to work out the ethanol pin on the ecu. if there is one that is & possibly some cam timing adjustment.

Not happy with the non-existent turbo noise/spool sound, I did some investigating of the factory air intake today and took some pictures along the way.

Unfortunately to do anything with the factory system, it requires removing the front bar which is about a 5-10 minute job. Once that’s done it’s a pretty simple process of removing a single 10mm bolt that holds the snorkel from the front of the car to the lower air box muffler.

The factory air box in the engine bay simply lifts out once the MAF plug and intake pipe are removed, providing access to the lower air box muffler.

I was surprised by what can only be seen as a somewhat over the top and restrictive intake system for such a small car. Not even the latest & greatest VF V8’s go this far!

So far for testing I have just removed the lower portion of the air box which I am calling a “muffler” box. While still retaining the front air dam director in place.

While there are aftermarket solutions available for the 1.4T to replace the factory kit, there are currently none being marketed to suit the 1.6T & All though the same kits may fit, I will let someone else take the chance. Personally for the price I believe I can have one made up to suit locally and that will be my next step.

For now, I’ve at least checked to see if it will be possible for what I have in mind for Phase 2 and once that’s done, maybe Phase 3 will be a new front mount intercooler and pipe work? Who knows.