Thread: D2a TD5 - more mods?

I'll give it a go but I'm fairly confident the gps is accurate as I've verified on point to point runs and roadside speed warning signs. Plus on the M1 if I go to 110 I'm cruising past most.

Haven't been out of low range in a week, hooked up to the van ATM towing it up and down the driveway working on that (lights, toolboxes etc)
I do need to organise the LT230 rebuild asap so I better verify this sooner than later.

Originally Posted by johntins

Yep. I'd avoid the earlier TT ones as well. Had some very bad habits.

The Utes normally have their top gear replaced too. You cannot use top gear if you tow as its weak. There are auto conversions though, but not cheaply.

Injector replacement costs lots 'coz there's more of them.

Originally Posted by AdamHunter

At 100indicated I'm doing 108gps and sitting abt 2200rpm.

Sounds about the same as my brothers too.
He's running 245/75 BFG KO2s.

We clocked it at about 107-108 at 100 as well.

AFAIK, I don't think the transfer case has been modded with any other gearing, but don't know. Previous owner didn't mention it, but did mention the recently rebuilt trans(later confirmed as very clean, but the auto place when taken for a service).

Something doesn't sound right about those RPM and speeds. I would imagine 2200rpm running 245/75 16 would be about 105. When mine had factory 235 70 16 the speedo was bang on.

I run 265 75 16 with 1.4 ratio transfer and 100km/h is 2500rpm with auto. With the speedo being approx. 10% out. e.g 90 is 100.

I'd check out Ashcroft's ratio calculator if i was you before changing any ratios. You might be able to work out hat ratio you have using it.

BTW I've got pretty much everything you were considering, 1.4 TC with single piece cross pin, remap and HD Ashcroft torque converter. I wouldn't recommend 1.4 ratio with those tires sizes with an auto it will rev too high. Not sure about manual and 5th gear though.

Originally Posted by Jazzman

Something doesn't sound right about those RPM and speeds. I would imagine 2200rpm running 245/75 16 would be about 105. ....

The actual tyre in use also makes a slight difference. Found this out the hard way many times prior to GPS availability(in mid 90s).

Would get a set of tyres of a different brand/make/pattern/etc, but the same physical specs, only to find that they geared the car slightly differently to the previous tyres when new.
I know that new tyres vs old worn tyres can impact slightly, again dependent on tyre brand and pattern too.
The most variance in new tread vs worn tread (1-2mm of thread remaining) has been 3km/h at about 2250 RPM.
Back in those days tho, if you didn't have expensive gear to test you had to rely on the overhead gantry speed indicators. How accurate they were is anyones guess.
I find them pretty much spot on nowadays tho.

On a Disco, the 235/70 16 size is standard, so at 100km/h indicated, you should actually be travelling at something closer to 97km/h or so.
You'd assume that mud tyres with their large tread blocks would give a slight difference in gearing than straight up highway tyres too.

Originally Posted by Disco Muppet

Tried it with another gps? I ran 245/70 for a while and my speedo was bang on and 2200 rpm for 100kmh

That is Odd because I am running 245/70 Yokohama's and my speedo is out by 5-6K's at 100k.
I verified this by using 2 different GPS units, a Garmin GPS and a HX7.

My preferred alternative would be the Toyota cruiser with the 4.5L V8 Twin Turbo, either the wagon or double cab ute, which will be at least $70k.... Which makes me more twitchy....[/QUOTE]And I believe the front track is wider than the rear. Quick and dirty design option to fit v8. So works harder in sand and mud due to not using created front track for rear wheels. I think Marks makes a diff housing etc that fixes this issue.