Partsco.com Blog

In the continual hunt for more power and once all the simple bolt-on mods have been applied a mild or hot cam is a common mod to embark on . After a friend purchased a custom cam for his turbo’d Commodore he was left with his old factory LS1 camshaft,  I took this off his hands (for a small fee) with the intention of taking it the local cam shop for a regrind. I did a lot of homework on what I was trying to achieve with power and drivability so I had an idea of the grind I wanted to put on the cam. As I run an automatic gear box and intend to one day turbo or supercharge my car I didnt want an extreme cam so went with a grind that seemed to be a good all round performer based on comments from other Commodore owners on the LS1 (australia) forum.

So I went in to Franklin Cam Services with my specs and set Adrian to work.

While all this was going on I got onto tracking down new valve springs, retainers, guides etc to match the new cam. Again, after a lot of homework and speaking to the lads at Thunder Racing in the US, I ignored the usual Comp Cams items and went with a Patriot Gold spring kit which included dual valve springs and titanium retainers.

Another good mod to carry out while doing the cam is a 25% under-driven pulley, this has the effect of creating less parasitic loss from driving all the accessories such as power steering and aircon. It makes sense to fit one of these pulleys while doing the cam as you will have access to pull the old pulley and fit the new one.

After waiting a week or so for the cam to be done and the spring kit to arrive I waited for a suitable weekend to fit the new cam with the help of my mechanic friend, John. I had bought the 25% Pulley earlier so we fitted that at the same time.

So after the cam and pulley procedures were carried out we had to set about retuning the car to match the new cam specs.

Time for a test drive!! Well, the difference was noticable from the first turn of the key, the car had a very slight lump in the idle and the exhaust note was angrier (as stated earlier I did not want an overly aggressive cam so as to match the auto and give low down torque rather than peak rpm gains) .

Once we got on to open road and could open her up the gains were plain to see – good improvement in low to mid range torque while still being nice to drive around town.

While my own design CS Performance intake was probably the best intake available based on the conventional factory setup it was not the ultimate in cold air intake as it still had bends in the system and air does not like turning corners.

When a fellow Holden enthusiast and businessman approached me wanting to use my car as a guinnea pig to design a new OTR intake i was more than willing to assist.

So his fabricator set to work on designing the new intake and we used my car for tweaking the design to ensure good fitment.

What you see in the attached image is the end result of the hard work and is now one of, if not the best, Over the Radiator intake currently on the market. It takes one of the biggest filters of any other known OTR and can run with or without the MAF sensor.

I was not sure if there would be any gain over my conventional setup but soon found there were indeed gains both in throttle response and power, particularly at open road speeds.

One customer saw a 15rwkw power gain from simply fitting one of these intakes….very impressive numbers for fitting nothing but a new intake!

These intakes are available through Partsco.com Ltd so if you want to get good bang for buck and great under bonnet looks dont hesitate to contact us.

Anyone who owns a standard V8 Commodore (i.e. Non HSV) and drives it hard will have no doubt found the limits of their factory fitted brakes at some stage during a spirited drive.

While the brakes Holden fit to the V6 range my be suitable for a V6 – to go and fit the same brakes to the V8′s is simply a joke in my mind.

I put up with my brakes for a while until it was time for my first set of brake pads – after doing some homework I went with some Ferodo DS2000′s (available from www.partsco.com ) and what a difference they made! They had awesome bite, no fade and ok they had a bit of dust but nothing excessive and given the performance they offered in the factory brakes I was more than willing to put up with it.

While the Ferodos were great in the factory setup i still wanted more and given that I race my car I really needed something bigger with bigger rotors, plus i wanted to some bigger brakes to fill the big void in behind the 19″ rims!

Sometime later a mate of mine came round and showed his latest score from Drury Car Spares (local Commodore wrecker)….he had a nice set of HSV (Harrop) stoppers out of a GTS Commodore. These have the 343mm front rotors and 315mm rears with cross drilling and the calipers are a 4 spot front which give improved clamping over the factory 2 spots.

I was jealous! But I would have to wait and wait.. but my patience paid off and soon an identical set came up at Drury for $2k and i jumped on them. The rotors needed skimming due to some scoring but once this was done they were ready to go in.

Once fitted I was expecting a great improvement so out I went for a spin…..while they were definiteley better they were not as great as I was expecting and this is I’m sure due to the improvement I had already seen going into the Ferodo pads in the factory brake setup (seriously the DS2000′s in the factory setup is a great brake mod for those wanting improved brakes on a budget).

I think I can get an improvement with the Harrops if I go to a better pad but I will cross that bridge when the current pads get low enough.

If you want to get a bit more go off the line a lower diff ratio will help with getting the tyres turning that much more quickly and easily.

Factory ratios for the VT-VZ range are 3.07 and 3.46 for the Auto and Manual respectively – while I really wanted to go to 3.73 in my auto the opportunity arose to buy a mates manual diff (3.46) at a good price as he was upgrading to a 3.91 (which is a common ratio upgrade for the manual).

So I headed up in my car (along with the 3.46 gear set) to see the lads at Steelie Gears (Auckland). Being an Executive my car was only a single spinner (ie no limited slip diff) so this was remedied at the same time. The guys also beefed up the diff and put in some high quality Redline diff oil for longevity.

I was advised to not go ripping up the streets until a good 1000km was on the newly fitted diff so you can imagine how I felt driving home just dying to try out the new mod!! What was instantly noticable however was the cornering – turn in was markedly better as a result of the new LSD at the rear.

This mod is a hands down must for the serious streeter or weekend race car – it gives improved acceleration and actually eases some of the load going on the drive train as lowering the gearing naturally reduces stresses. The only real negative is you will be revving higher when cruising – while I used to sit on 1800rpm at 100km, I now sit on at 2100rpm at 100km. Not a huge difference to be fair but it will use slightly more gas (my car is not a daily driver so not a big concern for me but I can imagine some people might be more concerned given the latest fuel prices!)

You will also need to have your speedo recalibrated (via the PCM) as the computer still thinks you have the old diff in place and it will get all confused! This can be done by your tuner using LS1 Edit or EFI Live (Holden could do it too but they might charge an arm and a leg for the service!)

Better spark from MSD Leads

When people start generating more power in their cars an often overlooked part of the chain is ignition leads but these are very important to ensure a good electrical flow which in turn ensures good spark and a strong, full ignition.

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Positive Crankcase Ventilation and oil issue.

A common practice on many modern engines is the plumbing of PCV (positive crankcase ventilation) lines back into the intake – this is done in accordance with emmissions regulations.

The issue with this is that many engines have this excess air bled from the rocker covers where there is lots of oil flying around, so this excess air becomes heavily contaminated with oil before entering the intake……as you may know oil retards the ignition process and therefore dampens power.

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Improving throttle response without buying new parts.

A friend and fellow Commodore owner, John, who lives locally to me and is also a gun on his laptop with EFI Live (pcm tuning), has also got into porting and polishing the factory throttle bodies on the commodores.

While I had heard that upgrading the throttle body was a good mod I always believed this was more to do with buying a bigger diameter throttle body which were rather pricey, so when John got into upgrading the factory throttle bodies I wasn’t expecting much of a difference.. how wrong I was!!!

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While my car had 17″ HSV rims fitted when purchased I always felt they looked ok but lacked the street credibility of some big 19″ rollers. So I lined up some Koya Imagine rims and some matching 245 rubber.. while they are a great looking rim I found that the open style of the 5 spoke rim made my standard brakes look miniscule!

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With my car stepping up in the power stakes I now felt my single 2.5″ exhaust system was getting restricive – so I did a little more homework and after finding some back to back dyno tests carried out by Rage exhausts I decided a single 3″ Rage system, BB9062, was to be the weapon of choice.

Some say a single system acts as a better scavenger of spent gasses from the engine over a smaller diameter twin system.

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