Turbo the I6... yeah, yeah.

Yes, I’ve read the tech docs and they are all good – if your aim is speed and ++++RPM. I’m heading in the other direction. Yes, atm it’s an academic exercise but hey, I’ve got to start somewhere. I’m figuring it’s probably not going to be a good idea to goose the throttle continually just for the hell of it, if all goes according to plan. Hmmm, just how much torque does it take to spin an I6 main at 2000rpm?

The 3.9L EB wagon is doing 1800 rpm @ 100kph, so that’d be a 3.27 diff on 205/65/15 ‘s I think. However peak torque rpm for my 3.9L, I don’t know and there no (accurate) dyno’s handy to where I live anyway. So anyhow, here is a list of stuff to consider and add to it if you like:

1) The aim here is torque and low revs. Think truck engine if it helps you - it’s not about rear wheel kW only but Newton metres at any given rpm. And probably a new redline of 3500-4000. I’d like to drop rpm to 1400-1500@ 100kph, probably through tyre size rather than diff ratio…say, 245/75/16. Ground clearance is a side benefit. So speedo correction is required too.

2) How to guess-timate torque for early stage planning? I’m figuring it would need a custom cam, along the lines of a “torque cam” but with longer exhaust duration. The head doesn’t have to be super special according to my machine shop – a new AU mainly but he would recommend the best head gasket, new head bolts I can get, a BBM manifold operating on short runner and a lower setting rev limiter. He wants my inlet and exhaust manifold first though so the can be matched. I can get any amount of choice of suitable turbos from Denco Diesel (top blokes).

3) Torque, again. Light vehicles normally run above peak torque and lowest specific fuel consumption. Torque rise from idle to peak is the part of the curve I’m looking at, not the other side. Yes petrolheads, it won’t rev to 5000 anymore.

4) Just how flexible are the J3 chip parameters, given I’m going in the opposite direction to most?

5) The Turbo would have to be low inertia – it’s probably got to be already low level spooling at 1300rpm.

6) Shift points on the auto. The EB 3.9 has two TPS, one for ECU, one for the auto. It can’t be too hard to fool the auto and I’m thinking that’s the best place to do it.

Feel free to add to my list of things to consider or comment on the points above if ya got something valid to say. Crazy is valid.

Lastly, why think about doing this? One day I’ll tell about my long living old school Rear Wheel 415Nm 2.8TD Isuzu – but for the Falc, it’s because a Cat won’t fit and because I can.

Good luck with that!!!!