HF transmission - how helpful?

[StorminMatt]

Well, I talked about getting a CRX to do a D15Z1 swap on. But it looks like I will probably be inherting my brother's 1989 Civic HB. So I may just do the swap on THAT car. Anyway, I don't have a D15Z1 yet. But I did manage to pick up a 1989 HF transmission for a song at the local Pick-And-Pull. His car currently is running a stock DX motor, but with an SI transmission. Do you think the HF transmission is going to make a big enough difference in fuel economy to make it worthwhile to swap transmissions before I find a D15Z1? Or is the difference going to be so insignificant that I should just wait for the D15Z1 to do the transmission swap?

[SVOboy]

Depending on the type of driving you do and the fact you're going from an Si tranny, I would say you might see anywhere from 8-15 percent...most people I think see 8-10 from dx to hf/cx/vx or the like, but I haven't looked at anyone's swap stats in a bit.

I'd do it just to get the si tranny out and sell it,

[StorminMatt]

Well, there is really nothing particularly valuable about SI transmissions here in California. They are actually fairly common at the Pick-And-Pulls. And just about EVERYBODY who wants more performance just goes B-series. So I couldn't get much for it. On the other hand, the car will most likely be used for what it would be best for - driving on freeways on level ground. So maybe the transmission swap WOULD be beneficial to do immediately.

[SVOboy]

Ah, well, I've been out of the honda pricing stuff for a while, and I'm from NJ, so I don't really know...but I'd go ahead and do it. Should only take a few hours anyway, right,

[Matt Timion]

honestly, I think you might see more gains from the HF transmission than the z1... especially when you consider the amount of time/money it takes for a novice to swap an engine, change wiring, etc.

You're probably already breaking 35mpg with your current setup. I'm willing to bet you can break 45 with the HF transmission, assuming you drive properly, coast when you can, etc.

[StorminMatt]

Well, when it comes to engines, single cammers are also pretty cheap here in California. They are another byproduct of the popularity of B-series swaps. On the other hand, VXs are somewhat rare compared to other 1992-1995 CRXs. So we'll just have to see. As for the swap itself, I am actually quite familiar with engine swaps, including wiring conversions to use the newer ECUs. I've done quite a few swaps, including my own ITR-powered CRX (which is using a 1997 JDM P73 ECU). So the cost to me is little more than what I can pick up the engine for. Also, it would be nice to drop in a motor that is newer and less beat up.

As for current mileage, my brother burned EXACTLY the same amount of gas as I did (in my ITR-powered CRX) between Pollock Pines, CA and Bishop, CA when we drove up to Barcroft Lab in the White Mountains last August (although he doesn't need premium). So that puts his current mileage right around the low-mid 30s. We will see what this thing will do with the HF transmission.

[GasSavers_DaX]

Check out my gas log chart - you can see a distinct increase in economy after my HF installation.