Novaz Nissan Laurel aero-build thread

[Novaz_nz]

Hi all,
I'm very interested in eco-modding for my daily drive (and the race car to some extent), and thought I'd start a thread to keep track of what changes I've made, to get advice and feedback, and to show what can (hopefully) be achieved with a typical 3-box sedan.

Brief blurb about me: I'm 26, have been into cars for as long as I can remember, and love to tinker. I am a mechanical design engineer by trade and drive Solidworks usually, at the moment I manage a rapid prototyping company Objective Design Ltd - Product Evolution which is very cool.
At some stage I will start modeling the Laurel and see about getting it into Cosmos in a virtual wind tunnel.

The beast! A C34 chassis Nissan Laurel. (picture from Wiki)



Nissan's nearly top-of-the-line luxury barge back in the day. This one is the facelift model with a slightly smoother front end. Powered by a 2.8 litre (172cid) L6, non-EFi, non-turbo diesel.

Mine differs from the above thusly: I have steel wheels, I am missing the front mud-flaps, and I have a rubber door protector strip running the length of the doors just under the swage line. Also, I probably have more dents, and the front undertray is missing.

Still, one has to start somewhere!

[Tango Charlie]

Nice car.
So what's on the to-do list?

[Novaz_nz]

Back in the day it would have been a $30,000 US car, but since no-one here wants diesels they are ridiculously cheap ~$1500 US or so. The petrol ones are still hovering around $4000 or so.

I figure since it's a 0.40Cd brick that any aero mods would be significant. The mod list looks like this so far, in no particular order:

- Remove rear mud-flaps.
- Upper grille block (have to be careful on this, the alloy head doesn't like overheating!)
- Create an undertray.
- Front air dam (low front skirt).
- Belly pan.
- Side skirts.
- Diverters for the front and possibly rear wheels.
- Possibly entended roof line (via roof spoiler)
- Possibly extended boot lid if it works out on the S13.

I would like to do the "holy grail" of a towbar mounted kamm back. I nutted out how I would fab up a quick-release and swivel mount for it last night, to allow access to the boot. I would like to have it in place for a round-country road trip I'm planning to do early next year.
The extra storage space + possible awesome aero is very tempting! Just have to figure out how to build one and keep it legal here.

I am testing the economy with the "power" screw turned down on the diesel pump at the moment. I guess it's acting like a hard DWL setup. If the economy improves, I will be fabbing up a bracket to allow a servo to adjust the screw while driving. Low for cruising, and high for towing / steep hills.

[Novaz_nz]

Well I've been trying coasting in neutral, and on the way home from work I can usually coast for around 6.5km. Since the journey home is 16km, it means I'm at idle for around 40% of my journey
Downside is I have to climb the hills to coast down them.... I'll have to try coasting *to* work and see how it compares.

[Tango Charlie]

I love pulse and glide. It's a great way to get through hilly terrain efficiently. Pulsing up the hill with a good load on the engine is more efficient, they say. I'm waiting for my ScanGauge to come, then I will be better able to determine the best speed and gear for FE. On some parts of my daily commute, it's amazing how far I can glide and maintain a decent speed.
Do you have any instrumentation? It's difficult to determine the effect of a mod without it. Which is why my Vibe is still mostly unmodded...
C'mon ScanGauge!

[Novaz_nz]

Well, I tried it going to work as well, and could only manage about 4.5km. Makes sense as we live basically at sea level, so we have to climb regardless.
I don't have any instrumentation at all, Scangauge is a no-go and a vacuum gauge won't be of any help. Being diesel I have no ecu or vacuum!

[Novaz_nz]

Today I pumped up the tires to 40psi all round, and made an upper grille block (on the inside of the grille). With the tires pumped up that hard it sure loves to coast at low speeds!
Tomorrow I'm going to pull the rear mud-flaps off and if I can find any suitable material I'll have a crack at a front air-dam.

[Novaz_nz]

OK, summer is here at last! Means I can start lying on the ground again!

So, things that have happened since the last post: I have been running the tires at 40psi and have kept my upper grille block in place. Initial results seem to indicate that both have helped, and I am now hovering around 29MPG, even with some occasional towing in there.
However, temperatures are increasing, and the upper grille block may have to come out for Summer - will keep an eye on the temps.

The biggest news is that I found some Coruplast in a "free firewood" bin, and have made a front air-dam. No FE results yet, but initial impressions are that it looks tough, and strangely makes the engine seem quieter.
My guess is with less wind traveling under the car, it's just quieter in general? Weird.

Anyway, here are some pics.

[Novaz_nz]

Took the car out for a drive to a local black sand beach (Piha). It's a coastal road with sharp bends and steep climbs. It won't have done the FE any good, and didn't do my temperatures any good either. Half way there I had to rip out my upper grille block, so everything from now until Winter will be without it in place.

Also, the air dam seems to have increased wind noise around the wing mirrors. Might have to try some of that sawtooth.

Oh, and towing really nails your average MPG!

[Dust]

I would think that a turbo would help you out a bit, as would using veg oil.