less compression, more CRX mpg?
 

I just would like some other opinions.

Generally, I've been well pleased with my '87 CRX. 4 times, I've gotten
62. somethings mpg on trips. My last trip in cooler weather; I still cracked
60mpg.

I have read that the very 1st CRX with the 1.3 had a 4spd. Other data tells me the 1.3 had a 5spd. Can anybody confirm either way?

I also heard that the 1.3 was a 10-1 compression engine that required
premium fuel.

Would it be fairly easy to change a 1.3 found in a Civic body, and change it
to perhaps 8:5-1, or 8-1 so it could run regular gas?

The acceleration would be slower on the bottom end, but the key thing I'm
drooling over is it was the only CRX to have mid 3's for a final drive ratio.


It would seem like mid 70's mpgs would be possible w/o so much as even headers!


Any thoughts?


Thanks for any input!

This is all from ancient memory. I bought a new 84 CRX 1.5 serial #1018 in Houston Texas. Pretty sure the 1.3 was a 5 speed. It (the 1.3) had a lot of special stuff to get mileage. Even 1 less piston ring per cylinder. I think Road and Track took one and drove it 735 miles on a tank of fuel and got 73.5 MPG at 55 MPH (national speed limit at the time). The thing that keeps me from messing with one was the carb and vacuum lines. The 1.5 was CVCC while I don't think the 1.3 was. It took 13.5 seconds for the 1.3 to get to 60, while the 1.5 was right at 10 seconds. I averaged right at 45 in my 1.5 for 50 k miles before I sold it. Paid $7k new, sold it for $5k.

regards
Mech

From what I'm seeing on car-part.com, the 1.3L civic had a 4 speed and the 1.3L CRX had a 5 speed in 1984 (only year of th 1.3L CRX), however the earlier 1980 to 83 Civic hatch back with the 1.3L engine had a 5 speed.
From what I read, the 1.3L is also a CVCC engine and from my experience the carburated engines like that run best on premium anyway because of the lack of ethanol and it's only 10 cents a gallon more, at least here, so 80 cents per tank full, seems worth it for 70+mpg, if that is what you think you can get.

http://en.wikipedia.org/wiki/Honda_C...ird_generation)

This link shows the 1.3 as an 8 valve engine, which would not be CVCC for the 84 model CRX. Maybe my ancient memory is not too bad. I bought a 77 Accord, first year made, that had the 1.5 CVCC engine.

regards
Mech

That is odd, because Honda Automotive Parts
Shows the auxiliary valve in the head, that is the tiny intake valve that lets a rich fuel/air charge in right next to the spark plug, in my shop manual they do not count that valve when they are listing it as a 8 or 12 valve engine, looking at the rocker arm layout there are also 12 rocker arms in the 8 valve 1.3L head, at least in the shop manual, they also all are listing a 3 barrel carburetor from what I can tell, something only the CVCC Honda engines had.
Either way, it seems like unless you need a new engine, swapping to a 1.3L is going to be an expensive route to go and from what I hear, parts for them are getting hard to find, so rebuilding one before you swap it in is going to be even harder and as I said already, it seems like if you are going to go to the work and cost of swapping an engine in, spending an extra 80 cents per fill up is going to be worth it and your mileage should be enough better with premium gasoline that it will make up for the extra cost in fuel so I would keep the high compression.

The 1984-87 Civic and CRX sold in the US was CVCC, except for the fuel-injected Si models. The 1.5 HF and 1.3 engines had 8 normal valves and 4 auxiliary valves. The other 1.5 engines (DX/Si), had 12 normal valves, 8 intake and 4 exhaust. And the CVCC engines had the extra 4 auxiliary valves.

All manual CRXs had 5-speeds. Only the 1.3 Civic Hatch had the 4-speed.

Increased compression ratio - EcoModder

Compression Ratio Compression Ratio Chart Photo 6

Notice the OEMs have all gone up in compression (at least with gas engines) since the 1980s, not down.