I'm trying to understand what makes a CRX HF motor get such great gas mileage, is it possible to change just the Intake manafold setup and get that 50MPG? Gas is going to be going nutz just trying to save some money! I reside in Florida, seems the gas is going to get tight.

 

PM'd

 

There are a lot of factors to the HF motor like tranny, intake, 62 HPness compared to our dxs 92. So really you'd have to do it all. I think.

 

All you have to do is a MPFI swap amd the put in the HF motor and tranny. You still won't get as good of MPG as the CRX HF though. The HF cars are about 200-300 lbs lighter.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sikocivic &raquo;</TD></TR><TR><TD CLASS="quote">All you have to do is a MPFI swap amd the put in the HF motor and tranny. You still won't get as good of MPG as the CRX HF though. The HF cars are about 200-300 lbs lighter.</TD></TR></TABLE>

It might even be easier to swap to MPFI and use the HF intake/header/ECU for the swap. I'm not sure if the head/block are the same for the DX or not (probably not considering the HF is 8-valve).

I'd do a whole swap if I was you. You can get the HF motor/tranny for cheap if not free.

As for the 200-300 pound difference, there are many little things you can do to drop weight. You could drop some weight if you really wanted to. According to the Department of Energy, each 100 lbs only accounts for 1-2% of fuel economy. If that is true, 300 pounds would at MOST cost you 6% of the HF gas mileage. So you might get 48mpg instead of 51mpg.

Sounds like a very cool conversion if you ask me.

 

well I just so happen to have a D motor that came out of a 98 civic hatch, great condition so I figure do the mpfi harness, install that motor with a HF tranny and I should be rock'n I also happen to have HF doors, guess I'll carbon fiber the sun roof and hood to give me some weight back. Should be interesting...

 

I put an HF tranny on my 89 Civic Si. I left everything else as it was.
On a trip from Orlando to Tampa and back, I drafted a bit behind SUV's ( Not too close!) and I got a little over 50 MPG. It helps to cruise at about 2300 RPM at about 75 MPH. My next move is to remove the passenger rear view mirror and put the VX 13" super light aluminum rims I have in the garage and inflate the tires 2 lbs over the recomended pressure.