PCM FuseText Box:                                         DLB4 Next Generation Tuning Technology 
                                       LS1 - LS2 - L76 - L98 
The most cost effective given the $ per kw gain or improvement in vehicle 1/4 mile performance a reduction in 1/4 mile times of 1 to 1.5 seconds can be expected. This is where  all engine and auto transmission settings are optimised for a given vehicle and any modifications as per the following descriptions to achieve the highest power output 
and best fuel economy possible. After the initial tune any further engine modification that allows the engine to pass more air will require further re-mapping the level of which is dependent upon the level of increased airflow.  

300kw Auto Transmission  Calibration
The 300kw program auto transmission operating calibration allows manually selecting       second gear and it will not change back to 1st a must for 2nd gear burnouts for tyre warm    up for dragstrip runs.

                                LEAN CRUISE CONTROL
Lean cruise in some programs is not active, when implemented under pre set conditions it leans the air fuel ratio and improves fuel economy. In combination with a custom tune will achieve around 2 litres per 100ks fuel savings. 

                                     EXHAUST SYSTEM
A quality aftermarket exhaust system will improve performance output and release  that V8  sound.

                                      THROTTLE BODY 
Porting and polishing the throttle body has marginal benefits  with some claims that re-shaping and polishing the venturi in the throttle body changes airflow properties potentially interfering with idle quality in some cases, we have not experienced this issue.     The  hot water hose that passes through the base of the throttle body can be bypassed to reduce heat soak in the throttle body. What will give you an increase in performance is ensuring the throttle blade fully opens at WOT as most throttle bodies do not fully open, port matching  the throttle body to manifold can also help. 

There are several suppliers they are all variations on a basic design with the objective of eliminating  the induction of heated engine bay air  and reducing any induction restriction to  a minimum with maximisation of ram air effect they are superior to other types of cold air induction and can improve 1/4 mile times by up to .3 seconds. The most cost effective standard air induction system modification is the second hole in the existing air box modification with the Monaro type shield.

                                CRANKCASE VENTILATION
On some Gen111 engines a high amount of crankcase gases are produced resulting in oil vapor contamination into the inlet manifold effectively reducing the  octane rating of 
the  fuel resulting in a reduced level of performance, an air oil separator on those engines    can  reduce this contamination considerably and allow the tune to be further optimised. 

                                   STALL CONVERTER
Used to improve acceleration  by allowing the engine to operate higher in the rpm range   until  it reaches the stall speed of the converter with the added advantage of mechanical    lock up under light throttle to maintain fuel economy a 3500 stall converter can achieve  up to .4sec reduction in 1/4 mile times.

                         UNDERDRIVE CRANKSHAFT PULLEY
Used to reduce load on the engine giving improved throttle response up to .05sec   reduction in 1/4 mile times.

                             DIFFERENTIAL RATIO CHANGE
The second most cost effective behind the engine management upgrade for  acceleration   and  reduction in or 1/4 mile times of up to .5 seconds.

                                  CAMSHAFT UPGRADE
Once engine output has been optimised without opening the engine  usually the next modification is a camshaft upgrade which if selected carefully will work well with a standard  or a modified cylinder head keeping in mind idle quality is sacrificed with this   modification,  up to  a .5 sec reduction in 1/4 mile times can be expected.  

                                      RATIO ROCKERS
Used with a standard or modified camshaft they effectively increases valve lift increasing engine output up to a .15 reduction in 1/4 mile times .   

                                 CYLINDER HEADS MODS
Gen111 heads flow well standard improvements can be had with conventional performance head modifications.                       
Supercharging can be used in conjunction with any of the normally aspirated modifications including a modified camshaft as large overlap camshafts have no adverse effect. Positive displacement type supercharges have the advantage of instant off idle boost and a smaller rise in boost with high rpm when compared to the centrifugal type which are lower in boost  off idle and continue to increase in boost as rpm increases. While all forced induction systems should be intercooled the positive displacement type supercharger are the least efficient and generate the highest boost air temperatures while the centrifugal curved vane type are  more efficient producing lower boost air temperatures.

Turbochargers can be used in conjunction with any of the normally aspirated modifications except camshafts with increased overlap as they do have an adverse effect on 
cylinder filling, special turbo camshaft grinds can be used however the standard 
camshaft is more than acceptable. Turbo’s are the most efficient in minimising boost air temperatures however for performance application should be intercooled. Turbochargers do have more lag when compared to the supercharger option this can be kept to a minimum with roller bearing turbo’s and or correctly sized exhaust turbine housing this is a balancing act as you decrease the exhaust housing size to improve lag you introduce an increase in restriction at high boost high rpm resulting in decreased top end power.

                       OCTANE BOOSTER ADDITIVE

Some enthusiasts when attending a drag meeting will add a can of octane booster adopting the attitude it might help and can not do any harm. Lets assume the tune level has been optimised however there is low level knock of say 2 degrees at 4500 rpm you add a can of octane booster increasing the fuel octane rating consequently reduced the burn rate and eliminate the 2 degree knock. However you have also reduced the burn rate for every other load rpm point throughout the engines operating rpm where it was operating optimally effectively reducing the state of tune to less than optimal except where you have eliminated knock. Adding octane booster and then re-tuning for the increased octane level will achieve the full benefits of increased octane. 

Adding octane booster can reduce knock, however keep in mind that even the more expensive octane booster claims to add 4 to 7 points which does not mean 98 octane pump fuel increases to 102 to 105 what it does mean it increases to 98.4 to 98.7 octane. 

The variables are marginal and given the cost and the potential to adversely effect an optimum tune octane booster is not necessary to use except to overcome a poor tune knock issue. 

                  PCM RESET PROCEDURE:
1. Make sure the engine temp was as hot as it needs to auto switch
    the fan on, i.e. over 80deg.
2. Switched off all ancillaries, e.g. stereo, a/c, lights.
3. Shut down engine, Important make sure key is in Off 
4. Pulled the 10 amp BCM fuse (#29 in a VY2) from the under hood
    fuse box.
5. Waited 20 secs, then turned key to IGN ON, then await 3 beeps.
6. Turn key to OFF, wait 20 secs, replace fuse.
7. Start car, leave all accessories off. Engine will stumble at idle,
    then surge up and down while it re-learns the idle settings. 
8. Leave running for 5 mins. Should be ok now and will continue to
    learn as you drive. 


It is understood valve springs can be changed and the engine is still considered to be unopened

Stands for Over The Radiator Cold Air Induction .

The mass air flow meter is removed to eliminate the induction air restriction and the program is re-configured to operate off the map sensor.

Another name for mafless tune.

The mass air flow meter is maintained when optimizing engine output and fuel economy.

Is a modified auto transmission converter to allow the engine speed to be greater than a standard converter up to the stall converter specified speed.

Is short for the catalytic converter it is part of the exhaust system and it is used to reduce emissions.

Is atmospheric pressure for normally aspirated engines @ 14.7 PSI absolute or 0 boost.

Is used for forced induction supercharged or turbocharged 
@29.4 psi absolute or 14.7 psi boost pressure.

Is used for forced induction supercharged or turbocharged 
@44.1 psi absolute or 29.4 psi boost pressure

Text Box:                          Information

VTA  has included the following information as a guide to understanding the term  as it is used and an indication of the gains the particular modification can achieve. 

Included also is some information on LPG when applied to LS1, LS2, L76 & L98 as the performance equals petrol with a substantial reduction in fuel cost.
Text Box: Text Box:

        Cold Air Induction


             Throttle Body


Text Box:

Lean cruise software map

3D Ignition curve

Underdrive Crankshaft Pulley

Stall Converter

Oil Air Separator

Ball Bearing Turbocharger nTTurbTurbochargerTurbochargers

Centrfugal Supercharger

Text Box:             Fuse Location
Text Box: Log Graph
Text Box:

    Positive Displacement









Text Box: Text Box:      Phone: 0418204176              Email: vtatune@vtatune.com
Text Box: Text Box:        Mass Air Flow Meter