Just starting out (looking to build a highway MPG machine - '88-91 honda CRX?)

[MetroMPG]

Welcome to the forum! A CRX is probably a better place to start for a highway machine (better stock aero = fewer custom mods needed).

You should dive into some of the HHO threads here - your understanding of it is a bit shaky (Frank wouldn't have worded that quite as kindly!).

Other than HHO, looks like a solid plan for an MPG machine.

In theory by switching to regular my MPG's would go up since premium has more additives in it to keep the engine cleaner that means there is less physical gasoline per gallon of fuel.

Might want to read up on that too. One of the "additives" in premium is higher octane, which should let your engine run more aggressive timing, which would result in more power & fuel economy. On regular gas, the computer will pull the timing back to prevent pre-ignition/detonation, so you get less bang. Might save money though. Hard to say without controlled testing.

[California98Civic]

Originally Posted by BBrown7888

Is there an engine code for these? (B18, D16, ETc...)

If you have the skills and time for a swap, I would consider the engine from a sixth gen HX Civic (D16Y5), married to the tranny from a fifth gen VX Civic. The sixth gen is OBD2 and will support aftermarket onboard computers such as Ultra Gauge, which will be one of the best "mods" you ever do. The HX engines are more common and probably more often have lower mileage. And the HX engine has other features (two O2 sensors and EGR, I think) not on the older VX engines. But the VX tranny has taller gearing, though the HX is quite good too. The fourth gen HF Civic had the tallest, but its rare and I'm not sure it mates-up with the later Civics (?). For the engine, make sure you get the Federal version, because lean burn was not allowed in Cali and the Cali versions therefore don't have it.

Good luck! Please keep EM posted with your progress. We love photos!

[turbothrush]

If you can't find a crx hf then you might find a 92-95 civic vx for $2000 then spend 50 bucks on an mpguino. If you drive 60 - 65 mph and keep it in leanburn as much as possible you wil get good highway mileage.
92-93 vx had only drivers airbag. 94-95 models had both .

[BBrown7888]

Originally Posted by California98Civic

I would consider the engine from a sixth gen HX Civic (D16Y5), married to the tranny from a fifth gen VX Civic.

I found a few places online that rebuild D16Y5's and sell them with a 3 year warranty for less than a grand but no harness. is there anywhere besides a junk yard I could find a reasonably priced harness and ECU? It would be a homerun if I could find a 92-96 VX with a blown motor for cheap and do this swap but I dont want to try and fuss around in a junk yard removing a dry rotted harness from a totaled car in july/august heat.

[California98Civic]

Originally Posted by BBrown7888

I found a few places online that rebuild D16Y5's and sell them with a 3 year warranty for less than a grand but no harness. is there anywhere besides a junk yard I could find a reasonably priced harness and ECU? It would be a homerun if I could find a 92-96 VX with a blown motor for cheap and do this swap but I dont want to try and fuss around in a junk yard removing a dry rotted harness from a totaled car in july/august heat.

ECUs are available on eBay sometimes, but avoid the auto trans ECUs and the Cali manuals, which each have their own ECU codes. In my notes from when I was researching a similar question I have the Fed Civic HX manual ECU code as P2N-A22. But double check before any purchase. Also, look up H-Auto for parts. I think they do sales online too. Look them up. Have you seen this car? http://ecomodder.com/forum/showthrea...ral-21498.html It recently sold here on EM. Contact the seller?

[02ws6]

Find a CRX HF.. Lightest bodystyle, best highway gearing trans and if running it already has the goods to get good mpg on the highway...

Then later down the road do a D15Z1 or D16Y5 swap for better drivability and even more mpg.. Kinda the best of both worlds..

[BBrown7888]

So I'm having a heck of a time finding a CRX HF within a reasonable distance to me and the ones that I have found everyone wants $6,000 or more which is insane so here's my new plan.

1) find a CRX with a blown motor preferably under $1,000

2) Buy a CRX HF trans and a D16Y5. I have found both of these readily available online WITH warranties. I could have the pair shipped to my house for under $2,000

3) Purchase the wiring harness and ECU $?

Does all this sound as easy as it seems? Will I run into any mounting issues where I would need custom fabrication or additional mounting brackets? I have swapped many motors but most were all small block chevys, this will only be my 2nd honda swap. If all goes well I should have a CRX at 60mpg's with zero miles on the motor and trans which will be under a one year warranty for around $4,000.

[some_other_dave]

You can DIY on the harnesses and such, or there are several retailers that can help. For more $$, of course. I think the guys at Rywire : can get you a wiring harness, but it does come at a cost.

The HF transmission (be sure it's an HF one, the 88-91 CRX/Civic transmissions are tough to tell apart from the outside!) and the CRX chassis are built to go together. The trans should bolt up to any D-series engine as far as I know. I'm not sure if the mounts on the Y5 are the same as the ones on the A6/etc. If so, then you're golden.

The drive axles in the HF, and the hubs and brakes, are different from the other CRXes. They're lighter-duty and lighter-weight. I think the regular axles will plug into the HF trans, but I am not certain. If they do, then use whatever axles go with the chassis (and therefore hubs and brakes) of the car you get.

The guys at CRX Community Forum • Index page have a lot of knowledge of these cars. You could do worse than looking around there for a while.

-soD

[California98Civic]

Originally Posted by some_other_dave

The HF transmission (be sure it's an HF one, the 88-91 CRX/Civic transmissions are tough to tell apart from the outside!) and the CRX chassis are built to go together. The trans should bolt up to any D-series engine as far as I know.

This has been a point of confusion for me: I have seen claims online that the pre-1992 D-series engines did not have hydraulic transmissions, and I have seen it claimed that they did. Which is it?

[some_other_dave]

All I know is that every CRX originally came from the factory with a cable-operated clutch. I don't know if that was also true for the other Civic-based cars.

-soD