VX Sedan (VX engine into '95 sedan... power to weight OK?)

[379Kcivic]

I'm considering swapping a VX engine into a '95 EX sedan, my concerns/questions/thoughts are as follows:

1. I've found curb weights of EX sedans at about 2500 lbs, is that correct?
2. Assuming I can find HX wheels: if an EX powertrain is similar to VX powertrain in weight, then curb weight of a 'VX Sedan' would be about 2475 (25lbs savings from HX wheels)
3. So with a new power to weight ratio of about 26.9 vs. a VX hatch of 22.8, is this theoretical vehicle going to so slow as to be unsafe?
4. What about using DX/LX gears 1-4 and keep the VX 5th gear for highway?
5. Any thoughts on realistic city/highway/combined MPG with this hybrid?:

I drive 2500 miles/month and nearly all of that is highway.

THANKS FOR ANY/ALL INPUT!!!

[MetroMPG]

"Unsafe" is so relative and dependent on the driver/driving environment as to be pretty difficult for anyone to offer you an answer that will really help!

EG: I'm quite happy with a car that does 0-60 in 15 seconds. Are you?

Keeping the engine in lean burn mode is key to saving fuel on the highway, as you know. If you load the engine up so much (through high speed or other high load condition - eg. possibly too much weight for the engine in a hilly area), there's not much point in doing the swap. How fast do you want to cruise on the freeway?

A VX owner who has driven with 2 big passengers on board could probably answer your question about power:weight effect on holding lean burn.

Aero mods will help reduce freeway engine load too, of course.

[user removed]

No less than a VX with 3/4 of it's original capacity payload.
Got 68 MPG in mine on a pure highway trip with 500 pounds payload.

regards
Mech

[379Kcivic]

I guess my 'unsafe' question really refers to merging on to the freeway? That's why I was wondering if the shorter gearing of a transmission made up of 1-3 or 4 gears from an Si/EX or even DX/LX (or some combination) would help acceleration that much.

I am really only wanting the lean-burn & VX 5th gear for my highway time which I believe could be achieved for nearly all of my trip to and from work & not so much concerned about the few miles I do in the city.

Right now I routinely drive between 63-65 and that's worked out ok. My stretch of freeway is very flat.

Of course I'm also open to some 'invisible' aero mods like mudflap delete, LRR tires, 1" suspension lowering, synthetic oil, partical grill block, max tires psi, etc. [B]So assuming a properly running VX on flat terrain running, say 65 mph average could yield 50-55 mph...do you guys think maybe 47-50 [/B]mpg would be feasible? Wouldn't the better (?) aero of the sedan partially offset the increased weight on the highway? If I can knock on the door of 50 mpg with those changes and running basically the same speed as I do now I'd be happy.

THANKS TO ALL

[PaleMelanesian]

On the highway weight won't matter much, but aero will. The sedan is better for that because it tapers down in the back and leaves a smaller wake.

I've never found freeway merging to be the problem everyone makes it out to be.

[MetroMPG]

Originally Posted by 379Kcivic

I guess my 'unsafe' question really refers to merging on to the freeway?

Hard to say - I seem to do fine merging with my 15 second 0-60 cars :P But I don't know how your traffic environment compares to mine.

Another thing to consider is the final drive ratio, which affects all gears. The CX/VX had the tallest (lowest numerical) final drive, which is something you want to reduce RPM for freeway cruising.

Right now I routinely drive between 63-65 and that's worked out ok. My stretch of freeway is very flat.

Sounds pretty ideal. I'll defer to the VX experts/owners, but I'm betting you'd be OK.

Of course I'm also open to some 'invisible' aero mods like mudflap delete, LRR tires, 1" suspension lowering, synthetic oil, partical grill block, max tires psi, etc. ... Wouldn't the better (?) aero of the sedan partially offset the increased weight on the highway?

It should, yes, especially given that you drive in the flatlands -- weight would be more of an issue if you had hills to deal with (assuming trying to hold L.B.). And don't forget: smooth belly pan!

[379Kcivic]

Thanks for the responses!

And yes, I have been reading all I can about belly pans as well. My goal is for this to be a factory looking (aside from a couple 'upgrades' that the normal bystander wouldn't notice) civic sedan, that has the highway mpg capability of a TDI or hybrid.


Great website!!!

[94EGCoopey]

Another thing, are you decent at wiring? Even with the engine harness, you still have to wire in the egr and the 5 wire to the ecu. Then if your doing the VX CX cluster like I am, you need to wire in the upshift light.

[California98Civic]

Originally Posted by 379Kcivic

4. What about using DX/LX gears 1-4 and keep the VX 5th gear for highway?

I'm hoping to switch out my 6th gen DX coupe final drive gear for a VX gear I bought a long time ago, but other projects keep obstructing me. If you want to hybridize, I'd say do it that way... take the DX/LX tranny and swap the final drive gears. The final drive is where the big difference in RPMs at highway speeds will come from. Of course, all your other gearing will become taller too, as a result of the swap.

[379Kcivic]

94EG,

I'll probably be keeping the EX cluster, if only to preserve an OEM look; plus I'm always short-shifting anyway for FE (that is until the suspension is improved)!