HF vs DX motor - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 11-17-2007, 12:21 AM   #1
Registered Member
 
Join Date: Oct 2007
Posts: 298
Country: United States
HF vs DX motor

A short time ago, someone here mentioned slapping an HF top end on a DX bottom end. I was thinking about maybe trying this until I can get a D15Z1 to swap into my 1989 Civic HB. The parts can all be gotten quite cheapy at local pick-and-pulls. But I have to wonder whether this is really worthwhile. Would the economy gains even be large enough to matter? Or am I better off just saving my money?
__________________

StorminMatt is offline   Reply With Quote
Old 11-17-2007, 01:18 PM   #2
Registered Member
 
Join Date: Aug 2007
Posts: 107
Country: United States
That was me with the HF/DX motor. It seems to be working just fine but I only have about 500 miles on it at this point. With the old tires it was getting 50mpg at 60 mph or so. I got it some new tires but it is to soon to tell. It does coast a lot better now. I think you would need to put the HF trans in there though to get the 2000 RPM at 60 MPH freeway mileage

Another option if you don't want to pull the head would be to turn the motor into the 4 speed hatchback motor. It has the lower rpm torque like the D15B6. You would probably still want to use the HF transmission. Still a lot of work probably camshaft, throttle body/injectors, ecu.

D15B1

(Same as the D15B2 engine, but with a mild camshaft, and a restrictor plate between the throttle body and intake header)

* Found in:
o 1988-1991 Honda Civic Hatchback
+ Displacement : 1493 cm?
+ Bore and stroke : 75 mm X 84.5 mm
+ Compression : 9.2:1
+ Power : 70 hp (52 kW) @ 4500 rpm & 83 ft?lbf @ 3000 rpm
+ Valvetrain : SOHC (4 valves per cylinder)
+ Fuel Control : OBD-O DPFI


What kind of mileage are you getting now?
__________________

FritzR is offline   Reply With Quote
Old 11-17-2007, 01:26 PM   #3
*shrug*
 
Join Date: Sep 2005
Posts: 6,195
Country: United States
What're you waiting for on the z1?
SVOboy is offline   Reply With Quote
Old 11-17-2007, 04:47 PM   #4
Registered Member
 
Join Date: Aug 2007
Posts: 107
Country: United States
Quote:
Originally Posted by SVOboy View Post
What're you waiting for on the z1?
Those motors are very available JDM for $500 or less. If you want to get started in the right direction you'll need the HF trans for the swap. If you just did the trans first that would help by 5 - 10% acording to Gary Palmer here
FritzR is offline   Reply With Quote
Old 11-18-2007, 05:17 AM   #5
Registered Member
 
Join Date: Oct 2007
Posts: 298
Country: United States
Quote:
Originally Posted by FritzR View Post
Those motors are very available JDM for $500 or less. If you want to get started in the right direction you'll need the HF trans for the swap. If you just did the trans first that would help by 5 - 10% acording to Gary Palmer here
Well, I really don't have $500 to spend on a motor. And I am not in any particular hurry here. S I'll just wait and see what I can get. It would always be nice to find a motor that a swapper is getting rid of for next to nothing, though.

As for the HF transmission, I got one a couple of weeks ago at a half off sale at the local Pick-And-Pull. It ended up costing me around $40 - this is seriously the way to go if you want an HF transmission! I actually just got the transmission in the car today. And talk about an eye opener! Third gear is already taller than fifth gear on my ITR CRX. And needless to say, the instantly available power of the ITR is not there. Of course, it never really was before, either. So it's not like it's some kind of major loss. Let's just say that this is not a car for the mountains. On the other hand, freeway cruising sure is nice and quiet. It will certainly be a good, cheap car for, say, drives between Sacramento and the Bay Area.

As for mileage, I have obviously not measured it et. But this will be interesting. The car originally had a 1988-1991 SI transmission. So freeway revs were quite busy. On the freeway, mileage was no better than the ITR CRX - low 30s. But let's see what it will do now.

As for the Civic STD stuff, I actually have everything needed for the swap. I guess this is something to consider for the interim. I'm not sure how much it will help economy, though.
StorminMatt is offline   Reply With Quote
Old 11-18-2007, 07:45 AM   #6
Registered Member
 
Danronian's Avatar
 
Join Date: Aug 2007
Posts: 652
Country: United States
I would see how your mileage is before swapping in a different motor. The RPMs with the HF tranny will probably be so low that your mileage will go up a lot.
__________________


On the never-ending quest for better gas mileage...
Danronian is offline   Reply With Quote
Old 11-18-2007, 11:33 AM   #7
Registered Member
 
Join Date: Aug 2007
Posts: 107
Country: United States
Quote:
Originally Posted by Danronian View Post
I would see how your mileage is before swapping in a different motor. The RPMs with the HF tranny will probably be so low that your mileage will go up a lot.
And you should document you results here with a gaslog so the next person will know what to expect if they try it.
FritzR is offline   Reply With Quote
Old 11-18-2007, 11:51 AM   #8
*shrug*
 
Join Date: Sep 2005
Posts: 6,195
Country: United States
PM 78si...
__________________

SVOboy is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Swift 1.3 GT seats posted in Classifieds ...Anyone ever check the classifieds? Brian D. General Fuel Topics 4 10-01-2007 05:55 PM
XFi mirror caps? baddog671 General Fuel Topics 4 07-10-2007 03:51 PM
Doh! GasSavers_Crystal General Discussion (Off-Topic) 5 06-29-2007 02:39 PM
Can one person slow global warming? GasSavers_roadrunner Automotive News, Articles and Products 15 05-28-2007 07:18 PM
Need advice/info-Metro/HF related GasSavers_Lance General Fuel Topics 19 09-06-2006 10:12 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 12:45 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.