90 Civic Dx motor vs. Si motor for daily driving vs. 96 CX

[sevenspeed]

Okay I found a mint 90 Dx that looks good and has the dual port injection motor I think a D15, I know the transmission is geared better for economy then my Si transmission, but I was wondering if I should swap my motor into it if I get it. Mine is 108hp and if wikipedia is right the d15 hatchback is 70hp.
Also being a lighter car how do they compare to a 96 CX hatchback which appears to have better gearing. 90 DX is listed at .771 5th, 3.888 final, my Si is same 5th but 4.25 final. And Cx is .702 5th 3.722 final CX hp is also 108.

The Cx has some honda rot but hopefully not too bad, the 90 Dx looks mint with body kit so maybe better aerodynamics.

[PaleMelanesian]

My 96 DX is the same as the CX except it has a trunk. The gearing is annoying on the highway, but fine anything below 55 mph. My commute only has a short section of 55, the rest is lower, so it's fine for me.

Mine's nearly stock except for an obsessed driver.

[Tri91]

Nah, the 70hp is for an earlier model engine that wasn't used in the DX. The DX trim level has a D15B2 which is rated for 95hp. I find that power wise the DX without the AC on is the same as the SI with the AC on. The DX does have more body roll but you could probably take the antisway bars off your SI and put them on the DX if it bothers you.

Not sure that they do have different transmissions. All of mine have serial numbers of SL3-serial#. I'd think that it'd be different if they are in fact geared differently. They both spin at 3500rpm @ 75mph in 5th gear. Either way the DX does get better gas mileage.

Would be a little concerned with how that body kit was installed. I've seen one that was attached with woodscrews. It was rather loose because the sheet metal had started rusting out around the screws.

[some_other_dave]

Body kits are almost never good for drag reduction. They're usually there to look like they give downforce and cooling air and so forth, when usually they just add drag.

The DX is better all around for FE than the Si, with taller gearing and a smaller engine that is not optimized as much for high RPMs. The CX might be a better choice yet; it sounds like the gearing is taller at least.

I'd probably think hard about the CX since you can use a ScanGauge in it to help tune your driving style.

-soD

[sevenspeed]

Thanks, the DX is a hatchback so maybe it's labeled wrong?
Honda : Civic: eBay Motors (item 180549699147 end time Aug-26-10 10:45:09 PDT)
The Ef's are a lot lighter too.
And the CX
96 Honda Civic CX hatchback- 97,850 miles
You can't see the Honda rot in those pics, but the one's they sent me it's decently sized and the bumper is dropped down on both sides by the wheels so the attatchment points are gone.

They claim it's a Blitz which is name brand body kit for $1k and $3k paint job so I hope it's not put on with wood screws And also if it is a Blitz it might actually be more aero. I'd of course be making the grille a whole lot smaller. And the clear taillights and projectors would be gone too. I'd also probably sell the 17" wheels and tires after I got it or put them on mine to sell.
The Si does is geared for more acceleration for sure, at 70mph I'm at like 3350rpms. It didn't say what motor was in it but it's not multi-port so it's a D15 something. Wikipedia was where I got the 70hp thing said for 88-91 hatchbacks.
How different are the motors? Mine runs great, I'm not worried about the 18hp as I half throttle mine at the most but does dual port instead of multi-port injection make it less responsive or is that something that only matters at higher rpms? I don't go above 4k either so regular vtec wouldn't even kick in for me
The CX is maintained well but that rust scares me, my 89 wasn't too much worse then that but it had underbody rot too I didn't notice and it got worse. It's fixable if you don't plan on driving in winter I think. And I have a MPGuino that I need to fix I could use instead of a scan guage as well as an a/f guage I haven't installed yet. I gave up on looking for a Vx in my price range rust free.

[sevenspeed]

No A/C on the EF I really need that since I have a Husky. I suppose I could swap over my motor and a/c but trade transmisisons. Need a new discharge line though, raccon cracked it.
I'm trying to find a hatchback with a/c, less then 120k miles, $3k or under and no rust. A needle in a haystack probably, especially since it has to be a 5spd, original motor (don't wanna worry about a swap with a bad tune or wrong ECU,) and I don't like white or silver. From looking at KBB financing is probably not an option they list the CX with that many miles at $1.5K in fair condition, $2k in good conidition.

[Tri91]

Hmm, not labeled wrong. From the VIN, We get:
1HG - Passenger Car
ED6 - Civic 1500 Hatchback
3 - 4-speed or 5-speed manual/2-Door Hatchback
5 - DX (ED6)
L - 1990
H - Ontario Factory in Canada

Interesting that he lists a 5-speed manual as a modifcation, it must have been a 4-speed originally. So basically, the drive train is whatever he put in there,... 100% feedback positive though...

That DX's engine looks like my DX's but it isn't really possible to tell a D15B2 from a D15B1 from just looking. Unless you look at the block stamp. The difference between those two engines is just a restrictor plate in the b1.
The valve cover is red as is the throttle body cover. The color of the valve cover would mark it as being some particular specialty engine but, as far as I know, the throttle body covers were all black. So the guy probably just thought it would be cool to paint them red.

"...does dual port instead of multi-port injection make it less responsive or is that something that only matters at higher rpms?"
I too usually keep them both at half or less aside from merging and the like. My DX did have less responsiveness but it wasn't the engine's fault. The stock air intake was too restrictive for the DX. I'd throw the throttle open to make a quick merge and the entire engine would lunge violently and pause before picking up. The Si doesn't have that problem even though it has the same stock airbox. I fixed the DX by drilling a gazillion small holes in the bottom half of the airbox. Not a cold air intake but was a simple mod that keeps the engine quiet throughout the entire range. I understand that those CAIs get loud at interstate crusing speeds and I do a bit of that.
No vtec in these older engines but at around 3200rpm it does feel like something is kicking in. I think the computer starts dumping fuel in at that point cause it doesn't do the fuel economy any good.

Seeing as that 96 is all rounded, I would have liked to tell you that it would be a better aerodynamic starting point but have you seen this site's Vehicle_Coefficient_of_Drag_List a 0.33 vs 0.36 Cd. Back to the DX, the side skirts look like they'd have the same function as the stock mudflaps and give the air a smoother path between the wheels. Depending on how it is attached you might be able to do ABA testing. No comment about the front and the back.

Oh, I just mentioned the body kit cause, you know, some people use these as learning tools or are simply too cheap to do it right. Then sell their handiwork to someone else because they don't want to deal with the fallout. I happened to see an example of that which scared me away from buying that particular car and bodykits in general.

Swapping parts between an early 88-89 4th gen and the later 90-91 4th gen isn't as simple as staying within the same year. They made some mid-stream changes. They didn't retool the production line, but some things did get left out. Point being that a conversion wouldn't be a completely plug and play event. Nothing major that you couldn't sort out in short order though. As an example, the seatbelts are connected to the body in the early 4th gen but in the door of the later models. The connection points for the seatbelts are all there under the carpet and behind the lower molding which still has the opening for the belt. But the upper shoulder belt connection on the B-pillar doesn't have a nut welded on the inside. The hole is there but not the nut. I know that people have done a seatbelt swap before, so it is possible just more work.

I don't know what your timetable is but finding needles can be fun. Oh, rust! I don't have too much of that. Not in the normal places anyway. If you do find a nice one, try taking the rear interior out and looking inside the curved parts above the taillights and other places where they are known to rust. Production stardards weren't very high in those areas. Bare metal and bad welds. Getting some sort of rust treatment/prevention in there has done my cars very well.

[some_other_dave]

They did make DX hatchbacks; this car looks like it is one. The DPFI intake gives it away.

The body kit is either bad or horrible for drag. That cow-catcher bumper is trying to scoop extra air and push it upward, and the rear bumper is a big parachute.

Supposedly the MPFI conversion on the DX engine does add a little fuel economy.

I absolutely loathe the body kit, and I dislike black cars because of the way they heat up in the summer. I'm not real fond of the DPFI motors either. And body kits can hide a multitude of sins, like wood-screws holding them on, and untreated rust, or structural areas cut out and not properly repaired...

If you don't want to get the CX, I would keep looking.

-soD

[sevenspeed]

TiR91 Thanks very much for the info, it was very helpful, especially pulling the carpet to look for rust. I never would have guessed the 96 had a higher CoD then my 89. They are bigger too I think. I hadn't thought about the cow catcher, just figured it lowered the car and rounded things out but it probably is overexaggerated.
My time table is kinda short, I want to get something before winter and if I sell the 89 I need something asap. I might end up with the 96, that paint probably isn't cheap though.
How much difference does rpm's make? The CX would be 667rpm difference at 70mph from my Si (2619 instead of 3285,) but a 92-95 CX according to two websites has the same transmission as a Vx so 998 rpms less, but harder to find in good shape and low miles. I have an Excel sheet I made that I enter in wheel/tire size and gear ratios to find out rpms or mph.
Also, I found a complete Vx swap with 150k on it and he has the a/c system too. I know the motor would swap but what about the a/c? I doubt it would work but if the 96 has a/c and the Vx swap has a/c would I be able to rig something together?
What is the final drive on a Crx HF? I read 3.888 but seems like it would be lower. Is there a off the shelf aftermarket way to run a cable shifter in a hydraulic car?
And are hatches more aero then coupes? I like the hatch for room but curious.
Should I rename the post, random help me pick a car questions?

[pletby]

I used to drive a '89 5 speed civic DX hatchback. 450,000 km before the car cancer took her away.

As a side note, I have a friend with a '93 hatchback pushing 800,000 km. He took way better care of his, just got bodywork done and looks new again. Still peppy.