Honda CRX HF Gearing ...and/or engine swap

[Brian D.]

I only recently learned why my HF screams @ highway speeds.
Apparently there were 2 different transmissions available for
the HF (the "49 state" and the other one). My last HF had
the good tranny, which turned @ 2250RPM at 70MPH. The one I
have now is about 500RPM higher. I'd really like to swap that
5th gear for the taller one...but where can I get one of
those?

[Ryland]

www.car-part.com seems to have them, alot of them, cheapest/closest to me is $100 for a whole tranny.

it looks like there were 3 trannies in the HF, a "normal" one, a high altatude, and a californa only, I suspect you have the high altatude one.

[Brian D.]

Worst part is that unless I can get some inside information
from Honda Motor Co., it's just going to be trial & error
when I just start pulling gears out of HF's....as I know of
no method to deciphering which will have the tallest 5th
gear. I'll likely wind up with the same as what I already
have.

[SVOboy]

Yay, time for me to be of use! But first of all, introduce yourself in our intro forum, :)

[SVOboy]

http://crxmpg.com/8891dgearing.html

As you can see, the difference is not in the gears, it's in the final drive!

[Brian D.]

Great! Your from my (weekend) homeland...sort of. I drive from VA Beach to Monmouth Cty, NJ every weekend. Anyway, I don't know a whole lot about transmissions...and never cracked one open. What's the deal with the final drive? I sure wish I had my old '91 HF...now THAT was the tranny/gearing to have. Instead I've got this crappy gearing that makes me work like hell just to obtain 47MPG. I used to get 50-55 MPG in that old '91. Okay, what's my solution?? I'd love to go 6-speed...but somehow I don't see that as feasible. **Are you a Honda head? If so I've got more questions for you (FE questions).

[SVOboy]

6 speed isn't feasible unless you feel like fabbing up some awd b stuff, or awd d stuff, or going k series, :p

Anyway, the solution that's easiest would just be to buy another HF transmission, but get one that's 49 state this time.

Fire away with your honda questions!

[Brian D.]

Nice! Here goes: As much as I've been wanting to get this better (taller gear/final drive) tranny back again, I would still have to install it in this 63HP CRX HF of mine. I can't help but wonder though, what if I get my hands on the Civic VX ('92-95) D15Z1 motor...which makes 30+ HP than my HF does.....and couple that with the fact that I'd be dropping it into my HF body, which is ~200LBS lighter than the VX (not sure about motor weight difference). If I then couple that with the gearing from my HF tranny...and larger diameter (but lightweight, of course) wheel/tire combination....wouldn't I be in a major sweetspot? I would figure 92 HP would help me make decent highway power (on inclines & whatnot) where the little HF motor struggles. Wouldn't this combination be the perfect platform to work with for super high EF?

[SVOboy]

Yes, you've indeed figured that out well. It is the perfect plaform, and I really wish I had one but no luck finding one in good shape around my neck of the woods. I think there's an importer around you though, iono.

[Brian D.]

Ah. I rarely see these damn VX's. Saw one last night at the supermarket, but was too late to leave a note on the window. If I do track one down I'm going to be all over it. So should I assume the HF tranny bolts directly upto the VX motor? (just wasn't sure about that). Sorry to chew your ear off, but I only just found this site after 6 years of being an HF owner.

[SVOboy]

Oh, it bolts right up. And don't worry, I'm here to help!

[Brian D.]

Nice writeup on the ride-height lowering - using the lowering springs. However, didn't I recently read somewhere that if you use the stock shock/strut tubes for lowering the car --that they don't last very long at all?

[SVOboy]

It's true depending on how much you lower, I'm running tokico illuminas now though, :)

[Brian D.]

I see. So anyway, what size tires/wheels are those VX's? According to this website: http://www.miata.net/garage/tirecalc.html if I change my current setup of 175/70/13's to 185/75/14's, my speedo will be underexagerrated by 6MPH, therefore increasing (to my knowledge) my effective MPG. Of course I'll have a slightly larger contact patch with the 185's. But probably not enough to make a difference. As long as I can find a lightweight setup I'll go for it. As it stands right now I only run with +2 PSI above MFG recommendations. Let me know how your car rides with stiffer suspension COMBINED WITH high-inflated tires. Thx.

[SVOboy]

Car runs perfectly, nice and tight. Anyway, I think the VXs are 175/70/13, but not exactly sure. The HXs are the 14s, both are good, with the HXs you can run the insight LRRs though, so yay.

[krousdb]

And with the insight tires at 165/65/14, you have the same diameter as the 175/70/13's. No underexaggeration!.

[SVOboy]

:thumbup: dan.

[krousdb]

:thumbup: dan.

You are gonna sprain you thumb Ben.:D

[SVOboy]

It's not my fault, you're just TOO COOL!

[Brian D.]

sorry, I meant to express my definite WANT for the underexagerration. As long as I can run a larger diameter setup I'll be running a higher MPH at a lower RPM (even though my speedo won't show it). I DO want this. Call it a cheap way to change my effective gearing since I've got the larger circumferance, taking longer to complete a single revolution in a given gear. I want this. I'm sure I'm not the only one who does.

[SVOboy]

Oh, surely, you're not, but the HF is already very long on gearing and reducing the inertia and rolling resistance of the tires, I think, is worth it. :p

[Brian D.]

I've thought about that. Which is why I would only do this if I could find a larger wheel/tire setup without a marked difference in weight. I would assume backspacing could also play a (minimal) role here as well, even if the tire/wheel weights were to differ. Anyway, isn't this only REALLY a valid argument when referring to stoping & going (overcoming that inertia)? Once you've achieved your driving speed I would think that amount of rotating mass would tend to work more for you, rather than against. (Such is the case for flywheels....any why NOT to get a flywheel that's too light, right?) Calling all engineers/Physics geeks?????? "help"

[SVOboy]

Yeah, intertia and such doesn't matter so much when rolling already except mehbe in friction, but dan did gain ~3 mpg going from his 15s to his HX with LRRs.

[krousdb]

Yes, MPG on the highway but also I went from 185 to 165 wide in addition to the LRR. Who knows if less weight had to do with it. I suspect not.

[SVOboy]

Oh, I'm not saying about weight, just that large rims aren't always better.

[white90crxhf]

Great! Your from my (weekend) homeland...sort of. I drive from VA Beach to Monmouth Cty, NJ every weekend. Anyway, I don't know a whole lot about transmissions...and never cracked one open. What's the deal with the final drive? I sure wish I had my old '91 HF...now THAT was the tranny/gearing to have. Instead I've got this crappy gearing that makes me work like hell just to obtain 47MPG. I used to get 50-55 MPG in that old '91. Okay, what's my solution?? I'd love to go 6-speed...but somehow I don't see that as feasible. **Are you a Honda head? If so I've got more questions for you (FE questions).

maybe the california engine sucks also? i'm getting almost 50mpg out of my hf with si tranny, though i do drive slower, and accelerate slower than i did with my hf tranny.

what exactly is the difference other than poorer mileage with the california models, and why did california need a poorer performing car?

[SVOboy]

If anything it's not the engine, it's the ECU.

But anyway, they have stricter emissions, that's about all there is to it.

[white90crxhf]

yes but wouldn't better gas mileage = lower emissions? according to the government site the california car emmits 4.1tons vs 3.7 for the regular. or was california going after a certian pollutant?

[SVOboy]

I'm sure there's something about the lower RPM. They also don't allow lean burn on the VX. Same with canada.

[MetroMPG]

CDN VX's lean burn.

[SVOboy]

Then I mean HX! I know phil told me they didn't have the HX. (I think their/your regulations changed in 95).

[MetroMPG]

Forgiven.

No, we never had the HX. We also never had the XFi. I think both were likely marketing decisions more than anything else.

But we did have the Insight, so I doubt it's lean-burn related...

Edit: unless the Insight does something special, lean burn wise, that the HX couldn't.

[SVOboy]

The Insight might just get good enough mileage to offset the lean burn, Iono.

[krousdb]

The CVT Insight does NOT have lean burn. Perhaps only CVT Insights are sold in Canada?

[SVOboy]

Yakno, that's what I thought, but Phil told me something different. I can't trust these canadians.

[MetroMPG]

The CVT Insight does NOT have lean burn. Perhaps only CVT Insights are sold in Canada?

Didn't know that about the CVT & lean burn. Learn something new every day.

Both Insight transmissions were sold here though.

[Ron22]

I only recently learned why my HF screams @ highway speeds.
Apparently there were 2 different transmissions available for
the HF (the "49 state" and the other one). My last HF had
the good tranny, which turned @ 2250RPM at 70MPH. The one I
have now is about 500RPM higher. I'd really like to swap that
5th gear for the taller one...but where can I get one of
those?

Could be worse I have a 1986 HF with the High Altitude Trans and I have 3000RPM at 70MPH. One gen 1 CRX's (84-87) there were three final gear options
2.95:1 ratio in the 49 state cars;
3.55:1 ratio in the California cars; and
4.06:1 ratio in the hi-altitude cars.
Like it has been said before the 5th gear is not what changes it is the final gear.
What year CRX do you have?