Best rpm at 100km/h

Hi Eric,

Many thanks, I will be doing a bit of towing with it (1500kg camper) but want to get it set up for optimal revs and fuel consumption first then have it tuned for extra torque.

The (new) TD6 runs 3.9's but with 275/65/17 tyres (31.07 inch) which equates to 2228rpm at 100km/hr
The TD42T ran 4.111's with 265/70/16 tyres (30.6 inch) which equates to 2384rpm at 100km/hr

As I have the taller tyres, I am thinking of 4.111's to match it to the standard TD6's figures ie 4.111's with 285/75/16 tyres (32.83 inch) which equates to 2222rpm at 100km/h (plus the 4.111's are more common so easier/cheaper to obtain)

I have the intercooler from the old RD28T so when it is all set up it will be the same as a TD6 anyway.

Regards
David

David,

GU1 TD42T Wagon - 3.9's with 265/70/16
GU1 TD42T Ute - 4.11's with 265/75/16

Cheers
Geoff

Hi Eric, My GU 4.2tdi at 120kph on the speedo, sits on 2700 rpm, similar revs to your 100kph. I do 1200 km's per week on the freeway so im happy with that, But if i was doing less freeway and more weekend out 'n' about, those current gears would be great. It would bring Low range first gear to where it should be.... Michael

OOoppps, i meant david...

Hi Michael,

Just checked the calculator and yes it matches your figures almost exactly - 2714rpm at 120km/h. Mine (in current configuration ) would be 3165rpm at 120km/h which is almost an gear difference.

Regards
David

Hi Geoff,

My figures come from the Nissan brochures that I have downloaded over the years (this one was 22 June 1999). It has the 4.111's listed as standard for the TD42T wagon. Not saying that I am right or you are wrong or anything but just what Nissan has presented.

As indicated in the brochure, the only wagon to be released in the GU series 1 that had 3.9's was TB45E. Unfortunately it does not cover the utes.

I have uploaded the brochure to my site if anyone is interested - Patrol.pdf.

Thanks
David

Geoff, the 3 litre tdi has a slightly lower diff than the 4.2tdi and makes a fair difference to the revs in 5th gear, it must be 4.11... The 4,88 is really low but would make ease of steep up and down hill. mmmmmm

Michael,

I think you'll find the 3L has something like 4.3's (4.375-ish from memory). They're also a heavier duty rear unit (h260 vs h233 in the 4.2's) in the earlier manual version of the 3L. Same type as 4.8L.

My TD42T with 3.9's and 285/75's handles the load (TrakShak camper and effectively 4 adults plus gear) pretty well on the highway.
Lower gearing would be better for tight stuff, but I don't do a lot of that.
The 3.9's suit my use, but may be a bit tall for others.

Cheers
Geoff

Hi Michael,

I didn't do the conversion myself but instad have somebody do it for me. We did have a donner car that we migrated the parts from so I was sure to get everything I needed.

In the end we needed quite a bit but we could have spent more time fiddling around with things and done it with less.

Regards
David