Band Wagon Jumper, CRX VX conversion

[Porscheman912]

Ok, I have read Posts From Soletek, and Bunger. It looks like I am on the same band wagon, just a little behind the power curve. I have fast cars, but this started about 2 weeks ago, talking with a buddy, and trying to get him to get a car with better gas mileage, due to how much he drives. Anyways, one thing lead to another, and I was going to prove my point, that you did not have to buy a hybrid to get good gas mileage. Well, I found and got an 89 CRX CX, with full body mods for cheap, but with no engine or trans. I thought I had a D15Z1 Engine and trans from a VX locked down for cheap, but the guy did not get back to me, so I called a place in WA who brings in the JDM stuff. What I am trying to figure out, is which is the better way to go as far as trany. The HF gearbox, or the VX. I want to get the best Gas Mileage, and it looks like Bunger is getting great mileage. I never saw what Soletek finally got. After doing some research about the HF and VX engines, it looks like the HF til 89 was 60 HP, then the 90-91 had 72, but in 92 the VX went up to 92 HP with 98 Ft/Lbs of torque. I figure I would go with a turbo, just so I make sure the car can get out of its own way if needed, plus, I will be using the car to haul my daughter's gokart. So, any input about trans, and any issuse on what mounts have to be made for this conversion. I might be trying this with a Del Sol down the road, but need to start getting rid of some of my P-Cars.

[GasSavers_Erik]

From what I understand, the HF tranny is geared even higher than the VX. The HF tranny (2.95 final drive) lets you do 2000 rpm at 70, while VX tranny (3.25 final drive) is about 2200 rpm at 70mph.

But, if you are driving in the city much, the VX tranny would be better- because you could better select the best gear to be in to keep rpms as low as possible around town.

[Porscheman912]

which HF trany has that gearing, most I have found have been the 3.25. Does anyone have the number for the 2.95 one. I am going to be getting a JDM trans with a JDM engine.

[theholycow]

Beware, I've seen some posts lately from people who have difficulty getting proper D15Z1/equivalent from JDM sellers who mostly aren't familiar with the VX and aren't concerned with fuel economy.

[GasSavers_Erik]

The 88 CRX HF FED had the 2.95 final drive for sure (the CA and Hi alt final drives were geared lower) It looks like the 89-91 may have been 3.25


Here's a site with the 88 HF info see the post on Jan 22nd 2008 at 11:34 pm: http://crxcommunity.com/viewtopic.php?t=246

You can likely find an 88 FED HF trans using www.car-part.com

[Porscheman912]

Great, thank you for the info. I found one that is listed as a D15Z1, so I hope it is right. What is the difference between the D15b JDM, and the normal D15b?

[LxMike]

I thought my insight had numericly low gears but the hf has even lower ratios.

[GasSavers_Erik]

Hi LxMike- just out of curiosity- how many rpms are you running at 70mph in your insight?

[LxMike]

I've only had it 2 weeks and it hasn't been above 50 Tires are one size larger also 175-65-14.

using gearing and tire size i calculated these numbers


35 mph is about 1200 rpms

45 mph is about 1500 rpms

60 mph is about 2000 rpms

70 mph is about 2300 rpms

I looked around and found that my insight has very close tranny ratios to the vx.


92-95 Civic CX/VX--------- Insight

First : 3.250 ----- First: 3.46
Second 1.761 ----- Second: 1.75
Third 1.066 ----- Third: 1.096
Fourth 0.853 ----- Fourth: 0.857
Fifth 0.702 ----- Fifth: 0.710
Reverse 3.153 ----- Reverse: 3.23
Final 3.250 ----- Final: 3.208

[GasSavers_Erik]

Thanks for that info Mike- it is interesting to see what gearing Honda put in their ultimate mpg machine.