Aerocivic - how to drop your Cd from 0.31 to 0.17

[Christ]

That, and the fact that although he could obviously get better gas mileage from a lean-burn engine, it would be wasteful to throw away an engine that is already in there and still working fine.

[basjoos]

Originally Posted by rkcarguy

I disagree. Especially if he switched to the 3-stage VTEC which has lean burn and also 130HP hi-cam, he could see better MPG-over 10%+ possibly, and have more power on tap if you want it.
At a 95mpg best without a VTEC-E, a lean burn engine could push this car into the record books.

If I did install one of the 3-stage VTEC engines that weren't sold in the USA, where would I get the parts and maintenance needed to keep it running? My current engine has about 290,000 miles on it and is starting to burn some oil. so I expect it will likely need replacement within 2 years.

[Christ]

the 3-stage Vtec has 2 solenoids, which are interchangeable from other D-series Vtec engines, so that's covered.

The bottom end is simple, as well, since it matches that of just about any other D-series engine.

The cam, well, have fun with that one, no idea.

The valves and lifters would be the same as many other engines, as well. The only parts you'd really have to worry about are the actual Vtec activation motion assemblies (can't think of their names right now)

You could probably get another head for less than the price of a rebuild, should you need any parts, so it's not really worth it to worry about "maintenance" in that scope.

The only thing you'd need on top of what you already have is the ECU that controls the 3-stage Vtec, but you could easily set up the system on switches or activation, etc. so you could control it manually, and stay in the first stage for the whole drive, which kind of kills the idea of using the 3-stage Vtec in the first place.

The other thing is that the 3 stage engine doesn't have lean-burn, to my knowledge, and the lean burn ECU doesn't support 3 stage. You'd have to overcome that boundary as well.

[rkcarguy]

Christ, where did you get your information?
First, the 3 stage does have it's own unique double vtec solenoids.
2nd, it is a lean burn engine, but is uses it's knock sensor to sneak up on the lean burn "edge" instead of a wideband O2, which is actually better because it's much easier to tune if your running a chipped OBD-1 ecu like I plan on because the OBD-2 version is non-chipable and near impossible to find.
The rest of the parts cross over to USDM D16Y8 parts except the cams and rockers. Unless you are one of those idiots that never changes your oil, you should NEVER need to replace any of these parts before the life of the engine has passed. The head gasket timing belt water pump belts hoses valve cover gaskets are all avail at the honda dealer.
Lastly all of the externals-intake, exhaust mani, distributor, wiring harness, from the D15B/Z will bolt onto this engine and drop right in.
The Apex-i VAFC has the option of modifying/controlling VTEC ran piggyback with the stock ecu. There is an imput wire and output wire for VTEC. In conditions where the ecu has no vtec and you have a VTEC motor, you can tune the VAFC to activate it and richen the mixture as needed. To run the 2nd stage of VTEC you simply run the 1st stage from the stock Z1 ECU and the 2nd stage via the VAFC. The solenoids are only one wire each and very simple.
The only thing this engine lacks is roller rockers, as there wasn't room with all the lobes and cams under that valve cover.

Basjoos, by no means am I pushing you to replace your engine, it's just exciting to know that you are getting that kind of MPG and are not maxed out...there is more that can be done and better numbers can be had. I think this setup can obtain tripple digit mpg figures and invite you to check out my post "VTEC-E in custom built car".

[Christ]

RK - just assumptions based on what I know about Honda's engines. Are you sure the Vtec solenoids are dissimilar from the other D-series Vtec ones?

I wasn't aware of it being lean burn, so that was obviously not correct on my part. I was only ever aware of one engine that had the OEM capability for it, that being the Z1.

[rkcarguy]

They have one casting that bolts to the head with a pair of solenoids, I've got the two motors right here in the garage. Most people don't know what the 3-stage is, as it was never offered in the USA. Our japanese supplier didn't even know what it was, we just got them as another D15B and when they showed up I was like "what is that?" researched on the net and surprise surprise.
When I get some more time(daylight), I'll take some shots of the engine and post it. Taking the valve cover off is a special treat!

[Christ]

Sweet, I'd love to see some images of the special parts of that engine.

[FusilliJerry82]

I didn't know which thread I saw links to that had anything to do with belly pans I should post in, but I picked this one because its the most up to date.

Has anyone considered that a belly pan would substantially increase the dangers involved with an exhaust leak and also make such a leak harder to detect visually?

[eco_generator]

You would still hear it. Pretty much a non issue, unless you seal up part of the exhaust air tight... which would be bad because the heat would probably start to melt stuff first.

[TestDrive]

Originally Posted by eco_generator

You would still hear it. Pretty much a non issue, unless you seal up part of the exhaust air tight... which would be bad because the heat would probably start to melt stuff first.

You'd still be able to hear it if the leak is at or before the muffler.
If the leak is after the muffler, you're unlikely to hear it.