Gearheadotaku
Gearheadotaku GRM+ Memberand None
5/27/08 2:17 p.m.

What sort of gas mileage could I expect from a late 80-s RX-7 non-turbo? Manual trans of course. Thinking of getting one for a DD, but at $4 a gallon, want to get an idea of what I could be in for. Fuel economy.gov says 17/24? That sounds low...

jrw1621
jrw1621 New Reader
5/27/08 2:27 p.m.

A simple math comparison of a rotory engine verses piston engine is to multiply liters by 3.

If the rotory is 1.2L, that roughly compares to a 3.6L engine.

I would expect 17/24 from a 3.6L engine.

Gearhead_42
Gearhead_42 HalfDork
5/27/08 2:29 p.m.

Nope, that's about right. Sorry! :cool:

One of the biggest complaints with the rotary was the "poor" fuel economy for it's displacement... while in the same breath it was praised for the incredible power output for its size!

Never understood that...

CrackMonkey
CrackMonkey Reader
5/27/08 2:51 p.m.

My old 12A cars never did better than 20mpg. And they frequently did WAY worse - 15mpg was a typical tank. A fuel-injected 13B might beat that, but probably not by much.

Jensenman
Jensenman SuperDork
5/27/08 2:54 p.m.

Unfortunately they do not get good fuel mileage. :whatthe: I was lucky to squeeze 20 MPG out of my '82 on the highway. Of course, it didn't help that I like to trim my toenails in the fan.

Greg Voth
Greg Voth Associate Publisher
5/27/08 3:23 p.m.

Not good. Low 20's on the highway and worse around town.

However through the magic of megasquirt people have been getting high 20's on a good tune with second gens. More information on rx7club.

John Brown
John Brown GRM+ Memberand SuperDork
5/27/08 3:24 p.m.

nice analogy Jensenman!

P71
P71 GRM+ Memberand New Reader
5/27/08 3:29 p.m.

My 83 RX-7 with a carb'd 12A rotary gets about 7-9MPG while autocrossing, about 12-15MPG in town driving, and about 17-18MPG on the highway (70MPH). 5th isn't enough of an overdrive, I've been able to eek 21-22MPG out of going 60MPH on the freeway.

billy3esq
billy3esq Dork
5/27/08 5:01 p.m.

Mazda supposedly claimed that the '84 RX7 with a carbed 12A would get 29 highway, but I've never heard anybody get a number this high.

Woodyhfd
Woodyhfd GRM+ Memberand HalfDork
5/27/08 6:26 p.m.

I once saw an RX-7 with the license plate: "GAS-OIL".

ProDarwin
ProDarwin Dork
5/27/08 6:43 p.m.
jrw1621 wrote: A simple math comparison of a rotory engine verses piston engine is to multiply liters by 3. If the rotory is 1.2L, that roughly compares to a 3.6L engine. I would expect 17/24 from a 3.6L engine.

Aren't rotaries wonderful? The dimensions of a 1.2, the power of a 2.0, the weight of a 3.6, and the fuel economy of a 5.0!

They are fun though.

Feedyurhed
Feedyurhed New Reader
5/27/08 7:25 p.m.

Back when I had my 87 RX7 as a daily driver it would usually deliver in the high teens in combined driving. In the cold of winter it would actually drop down to 12-13 mpg. So I couldn't recommend it as an efficient or economical daily driver. Sorry to add more bad news.

Chris_V
Chris_V SuperDork
5/28/08 7:05 a.m.

I got 25-26 mpg highway in my '86 Sport when it was completely stock (NA 13B). Funny thing was I got 25 mpg highway out of the same car after I put the nearly 380 hp 302 in it.

None of my earlier RX7s or RX3s did anywhere near as well.

Xceler8x
Xceler8x GRM+ Memberand New Reader
5/28/08 7:43 a.m.
Chris_V wrote: I got 25-26 mpg highway in my '86 Sport when it was completely stock (NA 13B). Funny thing was I got 25 mpg highway out of the same car after I put the nearly 380 hp 302 in it. None of my earlier RX7s or RX3s did anywhere near as well.

But a rotary is the SOUL of the RX-7!!!111!eleventy!!!1

If u remuve the hotness then it ain't an RX-7 no mo!

Chris_V
Chris_V SuperDork
5/28/08 7:44 a.m.
Xceler8x wrote:
Chris_V wrote: I got 25-26 mpg highway in my '86 Sport when it was completely stock (NA 13B). Funny thing was I got 25 mpg highway out of the same car after I put the nearly 380 hp 302 in it. None of my earlier RX7s or RX3s did anywhere near as well.
But a rotary is the SOUL of the RX-7!!!111!eleventy!!!1 If u remuve the hotness then it ain't an RX-7 no mo!

You're right. it actually ran afterward. :twisted:

YaNi
YaNi
5/28/08 8:22 a.m.
jrw1621 wrote: A simple math comparison of a rotory engine verses piston engine is to multiply liters by 3. If the rotory is 1.2L, that roughly compares to a 3.6L engine. I would expect 17/24 from a 3.6L engine.

That is wrong. A 12A is equivalent to a 2.4L piston engine, and a 13B equivalent to a 2.6L.

My S5 FC gets ~19mpg city and 24-25mpg highway.

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