Modification Guide for VT-VZ HSV or Commodore owners

Modification Guide for your VT-VZ LS1 Holden Commodore or HSV V8

Author: Steve Bennett

For VE & VF see our Guide for VE- VF

Mafless Tuning LS1, OTR, Dyno Tuning

The suggested modifications depend on what the customer wants from the car, the model of the car and of course the budget for the car/project. This article deals with LS1 Performance, Cam upgrades LS1 and lists numerous LS1 Performance Upgrades.

Tuning

On most models, the pcm tune will make the biggest difference of all the activities, regardless of what modifications have already been done. Some cars with only changes to the tune they perform amazingly better than with the stock tune. eg. A stock standard VT-VX-VY with no mods will usually gain around 25kw at the wheels from just a tune and improve in fuel economy by around 15%.

We can perform a normal tune on your vehicle from $550 or  post you amail order tune in a engine computer for $500 we can also perform aremote custom tune using a device to suit your VE-VF from $699 including postage.

See more detailed explanation of VT-VZ LS1 Tuning methodsHERE

Air Intake

There are numerous brands of over radiator intakes (OTR) on the market. All of them provide gains in performance. This is due to them posing less of a restriction to the intake system and providing volumes of cold air via a more direct route. In well designed systems they are not able to induce any hot engine bay heat, this is important because every degree the induced air changes correlates with around a one rear wheel kw gain or loss in power.  Some intake systems are able to induce a lot of hot air from the engine bay and this cancelled out any benefits of them being able to induce more air.

Oztrack stocks carbon fibre OTRs which are $1150 including installation and normal tune. Alternatively we can provide a mail order tune and Carbon VT-VZ OTR  for $1050. We can also custom tune the engine and gearbox and supply a carbon OTR for $1249. 

Exhaust system

The first step for many owners is to get the car sounding more like a V8 should. Any catback exhaust system that sounds the way you want will provide gains in performance. There are many exhaust systems on the market and we have a large amount of experience, having tuned many cars with almost every configuration, we can offer the best advice as to which system to purchase. We have our preferred configurations and can help you achieve the sound you want for your application and price range. We only recommend the best value for your money spent and what we know you will like.

Extractors and Catalytic Converter

We favor the sound from 1"3/4 primary pipe 4 into 1s. The 4 into 1s often have a "beat" sound like an old school V8 and this is evidence of good flow scavenging happening. We would typically suggest using a 200 cell metal catalytic converter (or Cat) as these provide good flow and sound, while still filtering out more pollutants than a 100 cell cat. Standard ceramic cats easily degrade over time, are often destroyed from one small hit from a speed bump and never offer good flow dynamics or sound. Metal cats are also more resilient and last longer than ceramic cats.

Camshaft

Many aftermarket cams are available that can totally change the power spread of the engine and the personality of the car. Some small cams are available that drastically change the low rpm power and improve economy over the stock cam without any loss of idle quality. The other extreme are cams that give a big increase in power at 6000+ and have a lumpy race car like idle with a loss of fuel economy. We can help you choose the right cam for you. We have a variety of cams, we have designed in-house, to suit any application.  Our Stealth II  and GT cams have both excelled in their applications. The Stealth II is stronger right through the rpm range than the stock cam.  The GT cam with standard heads has made in an LS1 up to 315 rwkw on the dyno, idles lumpy and still drives nicely at low rpm.  Oztrack information is HERE

Often people take the opportunity to fit a 25% underdriven balancer at the same time since the stock one has to come off to fit the cam - these also gain a little more power, maybe in the vicinity of 5rwkw.

Heads

Improved heads can provide gains in torque right through the range and even an increase in fuel economy. We can assist you in choosing the right heads to suit your aplication and also have competitive pricing. Our heads are built in the USA. Strong gains are proven and well worth the money. We do not recommend heads that we know don't provide solid gains for the money. Recently one of our VZ LS1 Customers had an engine that made 343 rear wheel kw with our heads and GTX cam. This is about 30 rear wheel kw above what we would have expected with stock heads with everything else the same.

Forced Induction.

There are many options for forced induction setups. Unfortunately many of these aren’t worth the money. The cheapest kits often can be outperformed by a cam upgrade and they have no upgrade options. We have a vast amount of experience and offer only the best kits at competitive drive-in drive-out pricing. Call us to discuss the best option for your application and a free quote.

 

Go to our page that includes

Oztrack LS1 Performance Upgrades and Packages

 

 

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