Order of modifications

[Wonky]

Yeah, that includes the place that originally tuned the car. They are very well known and I don't doubt they do awesome work, just seems a bit crazy to charge so much just for a cai change and diff gears. Maybe I'm just used to import tuners that generally charge by the hour from my experience

Anyway, sorry to go a bit off topic OP

Scary!! If Chev had done your original tune he'd tweak the tune for free for you! Obviously from a business perspective there's a limit to his generosity so he'd eventually draw the line if someone turned up every few weeks wanting a tune tweak due to some minor change they'd made, but as long as they are sensible about it, no problem.

[bluedivide]

OP

I've got an LS2 but most of the mods relate to your build as well...

This is the order I did it in cos I hate wasting money

Exhaust - headers and full system
Intake - Alloy CAI and tune
Pulleys- Powerbond underdrive
Suspension - Pedders Sports Ryder and Nolathane bushes all round
Gearbox - out with the Auto and in with a T56
Brakes - Harrop Ultimates
Diff - Eaton TruTrac 3.9 and Harrop Enduro diff cover
Fuel Delivery - Swirlpot and hiflow pump

next
LSX 454, LS7 crate motor or local builder utilising LS2 block and LS3 heads

hope that helps

[Phillshz]

Your Calais will have 2.92 gears, same as my A6 ute had. I bought a very low km 3.45 diff from a guy who was upgrading his M6 SS to the 3.7s from a M6 HSV. 2.92 to 3.45 is a pretty significant jump (close to 20%) and it really woke the car up, particularly noticeable when exiting roundabouts. Interestingly had very little or no impact on my economy as with a cammed L76 (DOD removed) with 280+rwkw I have seen very low 9s on a 40km freeway trip.

As comparison, pre cam with 260rwkw and the 3.45 diff it did a 12.83 at 112mph. My previous SSV sedan with virtually identical mods also had 260rwkw on the same dyno and with stock 2.92 diff in very similar conditions at the same track ran a best of 13.17 at 108mph. Don't fall for the common trap of thinking utes are lighter either!

I remember reading a thread a few years ago where someone with a reasonably quick VE A6 ran at the drags with all the ratios 2.92 (Holden A6), 3.27 (HSV A6), 3.45 (Holden M6) and 3.7 (HSV M6) and concluded that HSV had it right - his best results were with the 3.27. A while after my 3.45s were in I got hold of a set of 3.27s and after much debate sold them on again as I decided I was more than happy with the 3.45s.

I have no experience with Trutracks but they add a lot of expense and particularly given your financial situation probably aren't justifiable until you have big power.

Wonk`s, I have Desktop Dyno and Desktop drag 2003. A simulated standard VZ SS A4 picks up 0.15 s over the 1/4 mile when a 3.46 ratio is used over the stock 3.07. Another 0.15 is picked up when fitting a 3.73. The biggest difference is the time spent in each gear. A 3.07 is ok in 1st as the 4L60 has a low 1st ratio, 2nd hurts as it takes a while to wind through it, 3rd isnt too bad as the ratio/rpm drop isn`t too big but it still winds out. A 3.46 gives the best looking graph ie rpms,speed,time spent in gear etc. A 3.73 rips through the gears (1st is done with in a heartbeat) and needs the rev limiter raised to avoid bashing it in 3rd gear.

The same trend is seen when using a M6 and the ratios used with the M6 (3.46,3.73,3.9)

Moral of the story, sometimes the best sounding ratio isn`t actually the best one for the job. Considering these are (fast sporty) family street cars first and drag cars 2nd.

Cheers Phill

[Wonky]

Sorry Phill, I'm obviously missing the point of your moral. The OP has a VE A6 and was asking about modifications which led onto discussions about diff ratios. Given we're talking about go fast mods one would assume he's looking for best pick up off the mark. Therefore whilst I love the 3.45 in my A6 the point I was making is that if he does change the diff, testing by someone experienced at the drags has shown HSV seemed to get it right with 3.27 for the A6.

[Phillshz]

Basically Wonk`s, I`m agreeing with you, sometimes the lowest ratio available isn`t necessarily the best for the what are "family cars" first and "drag cars" second.
Your diff ratio change netted a gain of 0.3s on a VE, the desktop drag program on a VZ also netted a gain of 0.3s when the ratio is changed from 3.07 to 3.73.
A VT-VZ A4 with 3.7`s is very snappy/punchy/annoying and feels fast but isnt much faster than plain old 3.07`s (when stock).

Not that holden are perfect but they would spend considerable time/money testing things (like diff ratios) to try and get it right. A 3.45 would be punchy but a 3.27 prob works best as you found out.

Merry xmas Wonky.

[QldKev]

I'll throw my 2c in here, but strictly speaking pre-VE and with a bolt-ons setup. Over the 1/4 the change may not be that dramatic for a diff change, but around town/0-100km/hr you really feel the difference. I lost over a sec 0-100 from a diff change alone. Also I believe over the 1/4 most people achieve a lot better than 0.3 improvement in the real world. I'm not sure were the statement "a VT-VZ A4 with 3.7`s is very snappy/punchy/annoying and feels fast but isnt much faster than plain old 3.07`s (when stock)." comes from? There is no way I find my A4 with 4.11 annoying and jumping from a set of lights to the speed limit it is definitely a great improvement from the 3.07, not just feeling fast but the stopwatch (GTech) shows it.

[macca_779]

For the OP. TURBOS straight up. You'll save in the long run. :close thread:

[Gmfan]

I just improve on the weakest area of the car each time i perform a modification so that overall performance is improved. With my wagon I think i did brakes, trutrac and gears, suspension, catback and tune then progressed from there.

[lmoengnr]

I just improve on the weakest area of the car each time i perform a modification so that overall performance is improved. With my wagon I think i did brakes, trutrac and gears, suspension, catback and tune then progressed from there.

Good advice!

Unless you have a Redline. SSV Z, or a HSV, the standard brakes are the weakest point.

[Phillshz]

I'll throw my 2c in here, but strictly speaking pre-VE and with a bolt-ons setup. Over the 1/4 the change may not be that dramatic for a diff change, but around town/0-100km/hr you really feel the difference. I lost over a sec 0-100 from a diff change alone. Also I believe over the 1/4 most people achieve a lot better than 0.3 improvement in the real world. I'm not sure were the statement "a VT-VZ A4 with 3.7`s is very snappy/punchy/annoying and feels fast but isnt much faster than plain old 3.07`s (when stock)." comes from? There is no way I find my A4 with 4.11 annoying and jumping from a set of lights to the speed limit it is definitely a great improvement from the 3.07, not just feeling fast but the stopwatch (GTech) shows it.

Around town a 3.73 is no doubt a punchy feeling diff and on the street it would feel fast aswell. I`m sure someone has done a real life 3.07 to 3.73 (A4) 1/4 mile time comparison.
My 0.3s comes from DESKTOP DRAG 2003, the biggest change is the time spent in each gear. 3.07 winds out vs 3.73 romping into 3rd asap and then winding out into the (stock) limiter, 0.3s and 1.5 mph faster than 3.07`s.

3.7`s might be annoying for some but fine for others. Not forgetting these cars are family cars first and drag cars 2nd for most people here. I was mainly agreeing with Wonky in regards to his finding of the lowest isn`t the best for the street.

Cheers Phill

[Wonky]

Times on the 1/4 are also affected by proximity to the finish line when the car hits max revs in the penultimate gear. If it happens fairly close to the line you either lose time by bouncing off the limiter or lose time by changing to the next gear i.e. for that reason times on the 1/4 don't necessarily equate to performance on the road where there's no defined finish line.

[team illucid]

Unfortunately most of us don't have the spare dollars (or permission from significant other) to spend a bunch of cash on many mods at the same time. That leaves us with doing a bit at a time. Given the bit at a time approach, if you had a Calais V V8 with single spinner diff to start with, what order would you do the modifications in?

in no particular order, some options are.

cat back
diff (TruTrack)
OTR / Tune
breaks
extractors / cats
speakers
etc

??

1.Tint
2.Full exhaust
3.brakes (unless you have a decent HSV set)
4.OTR and tune
5.Wheels/tyres/Suspension

That's it - no other mods, haven't upgraded a stereo in a car since I was a kid.

[Drizt]

Given my diff is a single spinner, what sort of dollars are we talking to convert it to LSD? (Factory LSD or upgrade to TruTrack)
??

[Wonky]

Cheapest way is to pick up an LSD from someone upgrading, typically from someone with an SS/SSV M6 (3.45) they're upgrading to HSV 3.7. That's how I got my very low km 3.45 for $500 or so. I'd definitely recommend changing from the stock 2.92 ratio to either 3.27 (HSV A6) or 3.45 (SS/SSV M6) because it really wakes them up and is the icing on the cake for all other mods. About $100 labour to do the swap.

Alternatively if your main aim is just the LSD and you're happy to stick with 2.92 you'll sometimes find people who've upgraded to 3.27 or 3.45 selling their oriiginal SS/SSV A6 diff for around $250 - $300.

[Drizt]

Cheapest way is to pick up an LSD from someone upgrading, typically from someone with an SS/SSV M6 (3.45) they're upgrading to HSV 3.7. That's how I got my very low km 3.45 for $500 or so. I'd definitely recommend changing from the stock 2.92 ratio to either 3.27 (HSV A6) or 3.45 (SS/SSV M6) because it really wakes them up and is the icing on the cake for all other mods. About $100 labour to do the swap.

Alternatively if your main aim is just the LSD and you're happy to stick with 2.92 you'll sometimes find people who've upgraded to 3.27 or 3.45 selling their oriiginal SS/SSV A6 diff for around $250 - $300.

Excellent. Thanks for the info.