Nissan RB into MkII 2500

[INDEEP]

Hi all,

At the risk of being stoned, I would like to offer for discussion a project idea I am in the process of bringing to life.

I've taken one unmolested '76 MkII 2500 and decided I want it to drive better than an R32 Nissan Skyline GTS-t.

Why? Because I HATE Skylines, but I love their driveability, reliability, and all-round usefulness as an affordable entry-level sports car, and the Triumph is a beautiful (although less than hugely popular, in Australia at least), piece of classic motoring that deserves to blow the doors off the occasional rice-rocket!

The heart of the R32 Skyline is the Nissan RB20DET (6-cylinder/inline, 2.0L, twin-cam, turbocharged). In standard trim it produces 153kW (205hp), or around 115-125kW (154-167hp) at the wheels.
Keeping in mind that the intake, intercooling system, and exhaust will all need to be custom items in order to fit into the Triumph, I have figured (based on researching the Skyline somewhat online), that it is not unrealistic to expect it to produce close to 250hp at the wheels.
With a turbocharger and injector upgrade to RB25DET (2.5L) items, and an after-market computer, I should see the RWHP nudging 275.

Clearly, the original 2500 axle won't stand up to this kind of power handling for long, so I'm seeking the advice of the good people of the Triumph register to offer any words of wisdom in regards to obtaining and fitting a more reliable rear axle assembly for my 2500. I will be using the car as a daily driver, with views to (very) occasionally giving it a work out on the 1/4 mile or at a track day or two (very, VERY occasionally).
My only real prerequisite, is that I needs to be a relatively affordable conversion/upgrade, not on the grounds that I'm a tight-wad, but that I'm making a point of keeping costs as low as possible as to prove a point to some enthusiasts that attempt to buy their way into a quick(ish) car.

Any assistance, constructive criticism, or advice that can be offered would, of course, be greatly appreciated.

For the record, no. I haven't tried fitting the RB20 yet, as I won't be picking it up for 3 weeks. It fits on paper.... I might yet have a nice low KM RB20DET for sale in the not too distant future!

Cheers,

Rus

[Mike Stevens]

Hi Rus,

An interesting project, but I don't quite understand your figures. You state -

In standard trim it produces 153kW (205hp), or around 115-125kW (154-167hp) at the wheels

and then -

that it is not unrealistic to expect it to produce close to 250hp at the wheels.

That's a heck of increase from 154 - 167!

Anyway, to the point. There is a reasonably common diff "upgrade" for the Stag that uses a BMW diff. The Stag and 2000 back end are similar enough that it might be a starting point.

Good luck. Having doing a few engine changes in the past (all Triumph sixes so relatively simple) I know you'll have lots to think about!

Cheers,
Mike.

[Andy Thompson]

Mike - power increase will come from bigger better intercooler, custom exhaust and increased boost and fuelling

INDEEP - Rear end will need total custom job. Consider either the Subaru Diff (LSD naturally) or perhaps the Nissan R200(?) diff which people in USA fit to TR6's http://www.goodparts.com/shop/index.php?categoryID=16

Plenty of those over here in OZ - suggest you also use the driveshafts ex Nissan - either CV from the donor of the R200 or 240Z style - They fit straight onto some R160 or R180 diff's

Would suggest you change the rear hubs too as they WILL fail with 250bhp

Brakes ex Nissan are probably a good plan too!!! I have GTS-t front calipers and Nissan rear calipers and discs

http://triumphwestoz.blogspot.com/2009_ ... chive.html

Also as you will need a large exhaust the subframe hole needs enlarging - I cut it out and welded in a section of Triumph tailshaft so I could fit 2.5" exhaust

[INDEEP]

That's a heck of increase from 154 - 167!

Hi Mike,

Yes, I'll admit, it sounds like a big increase (nearly 75%), but in new school terms, it's highly obtainable. From the factory, to say the RB20DET is restricted, is an understatement. There are companies here that claim anything up 30RWkW (40hp) by simply fitting an free-flowing 3" exhaust system.

Does anybody out there have any finer details of the BMW/Stag conversion? Sounds like it might be a good proposition. Some proven power figures would be a huge benefit at this time too, as a lot of what I'm doing is theoretical (at this stage).


R32 tuning guide

[Andy Thompson]

This is a R180 diff and Nissan 240/260/280Z etc driveshafts in a Vitesse (fitted with sedan rear end) - you get the idea hopefully

[Andy Thompson]

That's a heck of increase from 154 - 167!

Does anybody out there have any finer details of the BMW/Stag conversion? Sounds like it might be a good proposition. Some proven power figures would be a huge benefit at this time too, as a lot of what I'm doing is theoretical (at this stage).


R32 tuning guide

Don't bother - decent BMW LSD are like hens teeth - most use electronic traction control rather than a proper LSD - and the proper ones break too - seen several lunched by a Lexus engined 3 series - he said they were really sought after.

Use a Nissan LSD - no more (or less) engineering - far easier to get in Oz - mob over East Sydney or Vic(?) do rear hubs with modded Hyundai flanges - custom bearing carrier and massively stronger stub axle - will try and find details

[INDEEP]

Don't bother - decent BMW LSD are like hens teeth - most use electronic traction control rather than a proper LSD - and the proper ones break too - seen several lunched by a Lexus engined 3 series - he said they were really sought after.

Use a Nissan LSD - no more (or less) engineering - far easier to get in Oz - mob over East Sydney or Vic(?) do rear hubs with modded Hyundai flanges - custom bearing carrier and massively stronger stub axle - will try and find details

I do a bit of gravel rallying (co-driving mainly), I might ask around on one of the rally forums and see what some of the 510/1600 guys are running. Funnily enough, I hadn't thought to look that way...

I have heard of one place in Brisbane Greg Tunstall Mechanical that do Datsun driveshaft upgrades for the Triumph. I might try to call them and have a chat to them. I emailed, as not to make a nuisance of myself, but never heard back...

Decent info on any Triumph Saloon seem to be scarce as rocking-horse you-know-what here, so I really appreciate your input Andy. If you can find the details for the NSW/VIC mob that do the Hyundai flange mod, please feel free to pass them on.

[Andy Thompson]

No drama - will do - try Club Triumph Forum too - plenty of nutty modifiers there too - mostly UK based so different problem / solution to many issues .

I feel re-engineering with Nissan gear will make most sense as you will get the most compatibility - might even be able to use a Nissan tailshaft - modded/shortened to link to the Diff nose.

Bruce Pollock ( secretary@tsoa-wa.com ) of TSOA WA re-engineers heaps of Nissan stuff into Stags , saloons and TR's + Z cars. He did my brakes

[tr250]

If you're going to add the HP as Andy Thompson mentioned, the Nissan LSD rear end using Richard Goods kit. Of course that's for a TR6, but I bet he could come up with something for the 2000/2500 range. And check out http://www.goodparts.com/shop/index.php?categoryID=20

The upgraded axle assemblies. I know the hubs will fit as I've fitted TR6 hubs to my 2000...the axle lengths vary between models however. Contact Richard Good & see what the total length of the axles are. Some trimming to the TA may need to be done IIRC.

Regards,

Todd Bermudez
'68 2000 MK1 LHD/w Overdrive
United States