crx hf gas mileage question

[sblkcamaro70]

Does any one know the actual gas mileage the 88 crx hf got when it cam out of the factory. I heard it is very good. Is it cause of the low gear ratio of the 5th gear or is it cause of the sohc 8 valve that peak torque was around 3 grand or is it both?

[4-Door Flunky]

A friend of mine has a CRX HF, and he bought it new. When he first got it, it got over 60 MPG. Now, after almost 200,000, it only gets about 55 MPG.
The transmission is geared differently. Also, i believe it is a 4-speed manual with 4th gear being an overdrive.
The car is very, very light. Also, it doesn't come with a rear-view mirror on the passenger's door and has a very low drag coefficient.
The answer to your question is everything: DPFI instead of MPFI, different gears in the transmission and the differential, lightness of the vehicle, and good aerodynamics.
He claims he used to get 65 mpg, but that seems awfully high...
4DF

[banditkiller]

A friend of mine has a CRX HF, and he bought it new. When he first got it, it got over 60 MPG. Now, after almost 200,000, it only gets about 55 MPG.
The transmission is geared differently. Also, i believe it is a 4-speed manual with 4th gear being an overdrive.
The car is very, very light. Also, it doesn't come with a rear-view mirror on the passenger's door and has a very low drag coefficient.
The answer to your question is everything: DPFI instead of MPFI, different gears in the transmission and the differential, lightness of the vehicle, and good aerodynamics.
He claims he used to get 65 mpg, but that seems awfully high...
4DF

I own an 88 hf, its mpfi, it also has a rearview mirror on the passenger side...Its also a 5 spd. I credit good gas milage to it being extremely light with not alot of power, and long gears which make for low highway cruising speeds. I turn about 2200 rpm at 75 in 5th. I wouldnt say its any more aerodynamic than any other stock crx that was made.

[sblkcamaro70]

Thanks guys for you reply. i guess i have never really heard the hipe about a crx getting 50 some miles to the gallon any ways i am going to drop the hf tranny in my civic then i will have to put in the d15b6 head and the mpfi other wise there wont be enough low end torqe to pull the civics ass around (hf tranny 90ft/lbs torque @2000) what do you think. good idea bad idea of swapping out the tranny head and intake?

[slipknotcraig133]

Yea when i had mine i loved the gas milage. I got around for ever it seemed on a full tank of gas. The gearing is a big factor in it. You can get that thing to do somewere around 80 in second. Also its only an 8 valve head with a real small intake manifold runners. I think that they only have like 68 horse or something like that i know its not that much.

Now if you swap over the head your going to have to do some bottom end work. The reason is the hf head is an 8 valve and the head you are putting in is a 16 valve. The hf pistons only have 2 valve reliefs a piston. You will need pistons out of a dx motor. If you dont then your valves and pistons will become real good friends.

[sblkcamaro70]

i totally forgot about the pistons. damn. i am putting the 8 valve head on the motor not the 16 valve because the specs the book shows is the cam on the 8 valve head is set up for low end torque unlike the 16 valve is set up for higher revving. that sucks cause i just went through my motor and if i decide to replace the pistons(not a big deal i have them) i will have to go through the motor again. Next question i have is would the dpfi intake and the 16 valve head be ok with the hf tranny or would that put too much stress on the drive train with there not being enough lowend torque?

[turtlecrxsi]

16 valve head is fine with hf tranny. Some even just swap out hf final drive for highway cruising for better mpg.

[CRAWFM]

Originally Posted by sblkcamaro70

Does any one know the actual gas mileage the 88 crx hf got when it cam out of the factory. I heard it is very good. Is it cause of the low gear ratio of the 5th gear or is it cause of the sohc 8 valve that peak torque was around 3 grand or is it both?

i have a 91 crx-hf. i get 44mpg. thats better than my kawasaki klr650.

[Airborne!]

I remember when I had my brand new 87 HF. I would always get around 55mpg city or highway. Once I did get 72mpg on a 55mph highway run where the wind was behind me and I was behind a nice big semi. That one even shocked me.

[4-Door Flunky]

Ok, I'll admit that I didn't actually look under the hood. I assumed it had DPFI like my 1990 Civic LX.
I also assumed it would have the same transmission as my 89 DX hatch, which had the four speed manual with 4th being an overdrive.
If some came with a passenger door mirror, that's also news. It must have been an option.
Sorry for displaying my ignorance.
4DF

[Airborne!]

I know on my 87 HF that the passenger side mirror was an option that I got put on at the dealer. I don't think it was an option you could get from the factory though.