280ZX Engine Swap?

[LOST ONE]

I'm thinking about purchasing a cheap 1980 280zx in the neighborhood as a learning project.  I'd like to turn it into a DD, cruising in GT comfort and economy while having something sporty and different.  I realize I'm in the minority here and I like power, too, but sharp looks, efficiency, reliability, luxury, nostalgia, and uniqueness rank higher to me than ponies. One of my goals is to achieve 30 mpg, which to me is reasonable without being a hyper-miling nut. 

 

My question:  Is it possible for the L28 to deliver my mpg goal or will a transplanted 4-banger be needed?  If so, I've read the S2000 posts and that sounds do-able but pricey.  Could the knowledge base here recommend any other (affordable) lumps that would put out at least180 hp, transporting me to work within my 30 mpg budget in a reliable fashion in the lightened 280zx?

 

PS--I currently use a 1993 MR2 as a daily driver, 34 miles of mixed city/country, and get 31 mpg.  The 5 spd MR2 is fun in a go-cart sort of way, reliable, and efficient.  But it's sooooo small and hard to put on, plus it  beats me to death as it rides like a brick.  Sixty mph turns the tach to 3K and over 4K at a squirrelly 80 mph--way too busy and annoying.

Edited October 13, 2015 by LOST ONE

[FricFrac]

If you are hyper miling then you can likely get 30mpg.

 

Comparing 1980 technology with 1993 technology isn't rally apples to apples though.... you are way further ahead with a 1993 MR2 4 banger than a 1980 6 cylinder developed in the 1960s....

Edited October 13, 2015 by FricFrac

[Tony D]

A Megasquirt using a WBO2 and proper fueling discipline will do that. Do you have emissions that need to be passed and catalysts that have to live?

[BluDestiny]

And probably some really low geared diff, and larger diameter tires would help also. I was getting about 27mpg last time I drove cross country in my ZX (doing 80mph most of the way), and it was for the most part a stock EFI setup. I had a 3.9 rear end and 25" diameter tires.

[Tony D]

^^^I got similar, towing a trailer loaded with 800# of stuff at similar speeds. Nothing below 3,500 on the freeway. Averaged 22mpg over 16,000 miles of driving in three total weeks. This includes some stretches where I was running 5,250 rpms for two tankfuls of gas across southern Missouri and into Oklahoma... I think foolishness like that pulled down my average quite a bit!

[roger280zx]

My 83 with T-tops and most all other bells and whistles got 28.5 on my first road trip.  Atlanta to Valdosta (loosing altitude the whole way) but it was the first week I owned it so the digital speedo read 85 the entire way even flogging it to about 125-130 for brief periods.  It was 5 speed, stock 205/70/14, stock 3.9 open, and a fresh tune up.  On the return trip driving much more conservatively (no hurry to get home) she did 29.5 with the a/c blasting.  I would bet that with a few mileage oriented modifications like swapping an r180 with 3.36 or 3.54, loosing the cat, and a bit of tuning from BRAAP's efi thread you could do well over 30mpg and it would be a hoot to drive.  fc20 is not really known to be a great gas mileage engine, the off idle torque of a relatively stock l28 is what is gonna get the mileage.   

[LOST ONE]

My 83 with T-tops and most all other bells and whistles got 28.5 on my first road trip.  Atlanta to Valdosta (loosing altitude the whole way) but it was the first week I owned it so the digital speedo read 85 the entire way even flogging it to about 125-130 for brief periods.  It was 5 speed, stock 205/70/14, stock 3.9 open, and a fresh tune up.  On the return trip driving much more conservatively (no hurry to get home) she did 29.5 with the a/c blasting.  I would bet that with a few mileage oriented modifications like swapping an r180 with 3.36 or 3.54, loosing the cat, and a bit of tuning from BRAAP's efi thread you could do well over 30mpg and it would be a hoot to drive.  fc20 is not really known to be a great gas mileage engine, the off idle torque of a relatively stock l28 is what is gonna get the mileage.   

 

That sounds like the path of least resistance, thank you.  After doing more reading and taking advice from this thread, it seems like the best fit for me would be to get an 81-83 n/a 5-spd and drop-in an r180 with a 3.54 rear end.  That combo should yield a comfortable and efficient GT while being sporty and reliable at the same time.

[roger280zx]

The absolute most fun per dollar mods that I have done to a zx (with turbo swap being the exception) have been to remove weight.  It certainly will not hurt your gas mileage either.  Loose the cat if you can, and aluminum 2.5" pipe yields a small power increase and drops 45 or 50 lbs.  De-power the rack or swap to a rack if you have a recirculating ball, loose the A/C, power antenna, tag light, cruise control, small battery mounted on frame rail right next to the starter, LW flywheel.  Include some misc brakets, bitchin betty, yata yata pretty soon you have a 2500-2600 lb GT Z with original safety, reliability, and comfort.  And it hardly costs anything.  Well maybe not comfort if you ditch the AC that's up to you.  The aero of the zx is soooo much better than an s30, typically they lack some performance because they where so weighted down, but if you remove that weight...