Maloo Baseline and some dyno lessons for me

Thanks to Charley at Surrey Rolling Road I have a baseline.

This is in line with Oz numbers for a stock standard LS3 Auto, but pretty woeful none the less.

Maloo R8 SV A6 Baseline

Fuelling was consistently about 0.5 AFR out, so if I was braindead I could just add 4% to the commanded PE table and it would be about right.

But I try to avoid braindeath and instead will go the long way round, which should result in more accurate logging as well as better performance and correct tune values in the long run.

Afterall, if the airflow model is wrong from GM, then its going to mean timing values are out, not just fuelling.

Here is the log file from 2 runs on the dyno. See anything interesting?

Dyno runs

So a few things spring to my mind. First; 16.5* of timing seems very low. Sure there was a tick of KR (Knock Retard) but so little its not worth mentioning. Also max timing is only 18* in any case. So I need to check the tune and see what is being commanded.

Second thing I note is that manifold kPa is only 95, earlier in the run it was 99. So thats a definite intake restriction right there. Now considering the SV model has "bi-modal" intake for better airflow, this is particularly woeful. There is pretty much a solid 3-4% lost right there.

Final thing of partial note is long term fuel trims differ between banks. Now looking at the trims over time I can see they are similar but never match, this suggests injectors, engine, exhaust etc differ enough that fuelling needs to vary across banks. Max trims are 4% which is well within the ability of short term trims. So long terms will go as is my practice and short terms will remain. I can use short terms to adjust injectors to give one bank more than the other in closed loop and even adjust the tune to give one side more in open loop too. I did this to slightly richen up cylinder 7 which in the LS series is often slated to run slightly lean. (eg Corvette Foum post)

So with the tune up and the logging tool up at the same time you can enable highlighting. What this does is show you where in the tune you are at that point in the log. From this you can see that below in the graphic the log says I have 18.5* timing, but the tune says I should have 22! 

So where is the missing 3.5!? I did not log all the spark modifiers, but Id suggest that if its not burst knock paying a visit, then its likely to be some torque management playing havoc. Especially as the front wheels were not turning and the ECU/BCM may consider this abuse.

Highlighting logs and tune EFILive

In fact this is quite likely as it threw a few codes to do with the ABS system and a myriad of other things at the time. All of which were reset with a power cycle and scan tool after the dyno.

So there we go a baseline and some lessons for me in where to find more power.

You may ask why GM delivers a vehicle that doesn't achieve full power potential from new.  I would agree, its a bit sad. But then I wouldn't have a hobby! 

A cursory review of Oz forums shows that a common mod in the VF which gains best value is an intake and a tune. Strangely I have an intake (See last couple of posts). I also have EFILive! Popping an exhaust on doesnt seem to be necessary at close to stock power levels. I measured the exhaust and I am pretty sure it sports a 2.5" from the factory. This is far better than the chunderous 2.25" mess that they used to come with and explains why the Oz guys just do intake and tune. Some good results from that are had too.

So my mission will be to address the issues as follows;

1. Gain 4 or so kPa from a new intake (Rotofab Chevy SS 2014 aka VF model)
2. Clean up airflow model so that commanded fuelling equals delivered fuelling
3. Figure out whats taking the timing out and address the cause

What am I expecting to gain? Good question. Id be pleased with 10% which is more than some guys get from fitting a cam! Though of course their baseline was with tune. So that will be my next mission post tune.

The ultimate goal is to deliver more power than a supercharged GTS with a lighter weight and better fuel economy.

On that topic Im surprised that the Maloo drinks far more than the E1 with the LS7 in it. Its reading 17mpg average! Shocking. The E1 says 26, but really its more like 23 due to injector scaling. Still thats almost 50% more. So really my number 4 aim above is to increase fuel efficiency, which by using less fuel under power enrichment as well as freeing up the intake should be a natural consequence.