FE Difference DX vs HF Motor in CRX HF?
 

I was at the mechanic's shop checking on the starus of my D15B6 motor and again things are at a standstill. They can not find the wrist pins for the pistons. They have a JDM engine sitting there for a DX. It would be less to get this swapped into my car than the rebuild would have cost. How much decrease in
FE could I expect using the 16 valve motor with my HF Tranny in my 88 CRX HF?

I currently am getting 32 average around town out of a 90 corolla 3spd auto old EPA 26 - 29

Swap the DX engine in there with you HF tranny if it's your only option. Your gas mileage won't be as good as the HF but it will be better then the corolla.

If that's what you've got to work with, I'd go ahead. My guess is that you will see a 5% maybe 10% decrease in mileage, but I think it will be closer to what you were getting, or could get, than not.

I wouldn't put the DX engine in, as it's power curve is going to be all wrong for your tranny, you would be better off trying to find a free or cheap engine on hondatec.com or on Ebay from a CRX HF, as people are already ripping them out in hopes to kill them self while driving fast, it sounds like your mecanic is rather irresponsible,

I somewhat agree w/ Ryland. I bought a '95 Civic DX hatchback w/ 68,000 miles on it about 7 months ago. One of the first things I did was swap the tranny for a CX/VX tranny. Looking at the hp and torque numbers for the DX, I figured it would drive about the same as my former '95 VX. Well, I was wrong. The power curve is key. For the DX, it's all in the higher RPMs. Whereas my old VX had lots of low end grunt allowing me to climb substantial hills in the taller gears without a problem, my DX w/ the CX/VX tranny is completely different. I have to downshift on those same hills.

That said, it was still worth swapping the tranny b/c I probably get 6% - 8% better FE, and I consider the power loss a fair tradeoff. If I had to do it all over again, though, I would have waited to buy another VX w/ low miles rather than going w/ the more plentiful DX and a tranny swap.

So I guess if I need to go with the d15b1 motor from the civic hatchback that has 83 ft/lbs of torque at 3000 rpm like the hf motor?

If you have the DX bottom and the HF top, I think your going to be pretty close to the same as a complete HF engine. The only difference at that point would be the dish in the pistons and that is pretty miniscule. If the bottom end and top end are available, I'd go with that, you've probably been charged enough, already, without starting over on another engine. MOO

Thanks, that's what I did. And they are eating the costs so far since they could not do what they estimated. The had all the parts they needed sitting right there for a month.

Are you sure the valves will not hit the pistons? The reliefs are there for a reason.

Are you sure the valves will not hit the pistons? The reliefs are there for a reason.

Well if there are 4 valve reliefs in the piston and only 2 valves in the head I think it's a non issue