andrey320

Here is my plan – buy an ’88 DX sedan (2040 lbs) and swap in a VX or HX engine with an HF trainsmission.
Here is my questions –
- Is the HF transmission best for gas mileage or is the HX better?
- HX or VX engine? (HX will mean obd1 conversion but its 20 horsepower more)
- What to use for engine management? (keeping fuel efficiency in mind)
- Will I need to swap the whole harness?
- Any DPFI/MPFI issues?
Please provide any information/links you think will be useful to me.
Thank you.

bambbrose

iTrader: (1)

the guys at gassavers.org have a lot of info on the vx swap.

The hx is obd2, not obd1. Stay away from the hx swap.

The vx motor is the best setup. You need to stick with the HF transmission because its the only cable trans that has long gears and will work properly with your chassis.

You will want to convert to obd1 and run the VX ecu, the non california one. You will also want to be sure and get a good oxygen sensor with your engine because the 5-wire o2 is over $190 new.

You have to get the egr equipment and do the wiring for it to get the mileage you want. many people with crx HF with VX swaps get close to 60mpg

SIred91

x2......Did it with a crx and got over65 mpg on the highway.

reydio

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SIred91 &raquo;</TD></TR><TR><TD CLASS="quote">x2......Did it with a crx and got over65 mpg on the highway.</TD></TR></TABLE>

Holy!!! that's almost as good as the hybrids!!! Nice One!!!

UfoTofU

I was going to mention GasSaver.org as well, great site, great resource.

When you check it check out the garage and the top 10 hypermilers.

They helped me average 50+ on my 88 CRX DX with an auto!

cheap2

how many mpg i will get with that swap? right now i'm getting 34 mpg more or less with the stock d15b2 engine on my '89 civic hatch,i was thinking in rebuilding the d15b2 but if i can get more mpg with a swap i will go for it,i don't wanna spend too much money,i'm new in all this H world.

andrey320

Thanks for the replys guys! So why should I stay away from the HX swap? I know its obdII, but if I will be converting to OBDI anyway, why not?
SIred91, can you tell me more about your swap?

ComeOnKip

WOW. Not to get off topic, but the super milers on there are unbelievable. Suprised no one's put a newer tdi into an older mk1/mk2 golf or gti chassis. That'd probably net some ridiculous MPG too.

I think it would be much much easier to use an OBD1 motor tho.


Modified by ComeOnKip at 1:54 PM 9/17/2007

92civicfreak

in my crx w/ a jdm d25b i can get about 40+mpg highway. & thats doing about 75-90mph... If you are able to get that same motor, but the head that has the 3stage vtec you should be looking at an easy 60mpg... I will tell u, i drive the ***** out of my car... & i love it, fast, fun, & easy on the pocket... look up some of the VTI motors like the 95 civic vti's
http://asia.vtec.net/article/d15b/

gp70hs

Their are a couple of issues you should keep in mind.

The 88 transmission and half shafts are a different animal from 89-91. Ideally, if you put in an HF transmission, if you can get an 88, it would be the easiest. The HX uses a hydraulic actuator for the clutch, so if you were to use that transmission you have to put in an adapter for the clutch mechanism.

As far as super econ engines, the VX vtech engine seems to be KING. However, you have to convert to multiple intake injectors, rewire the harness for a 5 wire ecu, get a VX ecu and get it all to work. When they work, they are capable of getting great mileage. When they don't work, they will drive you bonkers, IMO.

The HF transmission, from what I've read won't be a tread burner, from a torque standpoint, but if your looking for mileage, it is a essential ingredient.

gp70hs

Oh, since your California, I should add that you have to get it all smoged and certified by a State Referee. Additionally, their are a couple of other things to be aware of, which I neglected. First, their are three versions of HF transmissions. They are California, High Altitude and everywhere else. Second, their are two versions of ecu's, California and everywhere else. California uses a 4 wire Oxygen sensor, where everywhere else uses the 5 wire sensor, for a VX.

You don't have to use the California versions, to pass smog, but you do have to pass.

For economy, you would want a non-California transmission and a non-California ecu.

wiZCo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gp70hs &raquo;</TD></TR><TR><TD CLASS="quote">

The 88 transmission and half shafts are a different animal from 89-91. Ideally, if you put in an HF transmission, if you can get an 88, it would be the easiest.

</TD></TR></TABLE>

Yes, but all he would have to do otherwise is get an 89-91 flywheel / clutch to use a 89-91 trans. They're not that different, they just have a different spline count on the mainshaft.

And it's "VTEC", not "vtech" BTW.

andrey320

Great info! Thanks!