MPG – the DAILY DATSUN

March 13, 2012

No Bumper = +5% MPG

You read right: by removing the hefty bumpers on the Datsun 280z, i was able to get a solid 5% MPG increase (19.5MPG).

While safety takes a nose dive, an extra 1 mile per gallon actually translates into quite a bit over a tank ~10-12 miles.
Though the real question here is: ‘is it worth it?’. Probably not. Which is why soon enough i’ll be putting on the 240z bumper (better than nothing, right?).

Now if only that guy on eBay would get back to me…

For anyone looking to purchase 240z bumper conversion brackets for their 280z, I’m not having a good purchasing experience with eBay user: v8-240z.
I’ve already sent two emails (via eBay and personal) and I haven’t heard back yet on anything (‘hey i got your email, i’m working on it”, or “shipped, here’s the tracking”, or “i don’t want your business”).
I would suggest zspeed240‘s listing instead.

March 5, 2012

No Bumper – Let the MPG Experiment Begin!

Obviously the Datsun 280z was never purchased as a gas saving, fuel sipping, economy car. Prius’ step aside in horror and repulse as the 280z zooms past their 60mph earth loving vehicles. :] But on the flip-side, with the rise in fuel costs (currently $4.40 for 87 grade gas in the San Jose area), I need to take action.

I found something interesting this morning: my average fuel economy, 18.5 MPG, is actually better than the average passenger car in it’s time!

Since my first tank, I’ve consistently maintained 18.5MPG on the 280z (my worst and best being 18MPG and 20MPG respectively).

Now fast forward 35 years, and it’s not quite the same. Though the fuel economy from the late 80’s to the mid-2000’s was stagnant, cars in the past 5 years have had a huge increase in fuel economy (the 2012 Hyundai Elantra pushes 40MPG highway). Though the 280z may never see those types of numbers w/ it’s L-series engine, the alternative to drive train replacement is to reduce weight. This weekend, Kris and i popped off the front bumper, est. a weight savings of ~25-30lbs.

Best to have all the right tools.

Stock bumper shock, ~5lbs each

Remounting the horns. There’s one on both sides.

While I wait for the new 280z bumper mounts (made to hold a 240z bumper), I’ll roll around bumper-less and see what kind of MPG we can get!

November 23, 2011November 27, 2011

And it gets…

Yes! you read that right, the datsun gets 18mpg :] Since it’s first fill up, i’ve driven 226 miles on 12.5 gallons. And… that puts it about par w/ other 280z’s i think.

So NOT the fuel sipper that the Scion xB is, but better than expected!

Oil Pressure – I’ve noticed the fuel pressure gauge is reading somewhere below normal. Supposed normal pressure should be at 45 psi, but the gauge is showing ~30 psi. I’ve also noticed on longer drives that the gauge will noticeably drop over time. But it can’t be too accurate as the engine should auto-shut off at ~2 psi, and let me tell you, i’ve seen that gauge hit rock bottom before.

Now there are a few notorious things that could be the cause of this: 1) electric gauge is only an estimate, not as exact as a mechanical gauge, 2) oil pressure sending unit (or oil pressure gauge) is known to break down after a while, 3) possible oil pump, 4) need a thicker oil.

First thing i’ll do is check the pressure w/ a mechanical gauge straight from the engine. That’ll give me a true reading from which i can assess whether the dash gauge is correct or not. If so, I look at replacing that oil pressure sending unit. The “sending unit” is located next to the oil filter right on the engine block – kind of looks like a spinning top.

**Note** 1977 was a funny year – there are early and late models that have differences (ie. trunk deck shape). The Oil Pressure Sending Unit is also different: Early model had a bullet point terminal (shown here); Late models have the spade terminals. Also, it seems like general consensus that the Nissan factory units are better than the 3rd party brands.

~~Motorsport Auto has the proper one for my late model Datsun 280z: http://www.thezstore.com/page/TZS/PROD/17-8003~~

11/27/11 – Okay, so now i’m not so sure… my 280z was built in 4/77 which should make it an early model Z and it has the bullet type terminal (sorry NOT the spade terminals), but MSA has the spade terminal oil pressure sender for models made in 3/77-84! what gives?! So possibly the one i have is incorrect for the year. <- needs more research…