Thread: V8 Exhaust, what a note

Originally Posted by PaulP38a

i reckon you'd get it down to the 2200-2300rpm range but you'd also go too fast downhill in low range with standard diff gearing. I do like the idea of changing the transfer case low range gearing only.

you can get a speedo correction unit for the bigger tyres that hooks in to the ABS sensor i believe. I have found nothing in the FaultMate that allows it to be set via software though.

Cheers, Paul.

Mine sits at 2250rpm at 100km/h now with factory tyre size! I'd hope it would drop if I wacked another 4" of tyre under the guards :-p My Torana changed by about 6km/h (at 100km/h indicated on speedo) when i went from stock 13" skinny's to bigs-n-littles, and the tyre size at the rear went up by about 2"!

I'll be visiting the Hard Range website frequently for the next few months while I decide exactly what I should treat myself to for Christmas!

Cheers
Keithy

there you go! shows how long it has been since I've had a Rangie with standard tyres and diff ratios

Originally Posted by Keithy P38

If you kept the standard gearing what revs do you think you'd be sitting at on the 33's at 100km/h Keithy

I was bored at work so did some maths.

Using these three tyre sizes
1. Standard 29" tyre (standard P38 size) - 2.318m circumference
2. 30.5" tyre (Mine) - 2.442m circumference
3. 33" tyre (Paul's) - 2.639m circumference

At 100km/h with standard gearing it should work out to be:
29" = 2253rpm
30.5" = 2139rpm
33" = 1979rpm

With 4.11 diffs like Paul has it should be:
29" = 2616rpm
30.5" = 2483rpm
33" = 2298rpm

The figures aren't exact as tyre diameters vary from brand to brand, tread to tread (muddies tend to be bigger than road tread) etc but gives a good ballpark. Personally I wouldn't go to 33's unless you regeared the diffs too, accelleration and hills would suffer too much I reckon. First gear low wouldn't be slow enough either for good descent control. I notice it already on mine and I've only got 30.5's

edit: 4.11 or 4.1 diffs look like they'd be perfect for 33's to keep the stock gear ratio

Will try to find a stretch of road on the way home tonight where I can sit on 100kph (legally) to test the 33" numbers.

I tend to watch the temp gauge more than the tacho

BTW: sincere apologies to Wanglemoose... this thread was supposed to be about the sound of his exhaust... which is very nice indeed.