fleabag

I was wondering if a person with a D16Y7 or some 4 valve variant of a D series who wants to change out the cam profile to one that would match a Civic VX when it's in 12 valve mode, would they need to change out the ECU as well? I understand that it is necessary to reprogram an ECU when one switches to a more aggressive cam profile than the computer had been designed with or when they turbo out their car, but what if they put in a less aggressive cam profile? The only reason that I know that it should be ok is because this guy: http://www.metrompg.com/posts/xfi-cam-swap.htm did it with out changing out the ECU and had excellent results.

Red_Army

ride a bike if you wanna save money. honda makes bikes too.

fleabag

no thanks. I prefer the convenience, safety and comfort of a car.. If I can average 50mpg in a car with a few modifications, I'm all set.. I don't need a 0-60 time of 8 seconds... let alone 14..

Furthermore, I'd like to say that this just so happens to be what I want to do.. You guys want your 0-60, quarter mile times and lap times while I want miles per tank of gas, MPG and low cost of operation... What you said about the bike could have easily be said for your desire for a faster car as a bike is much lighter and has almost zero emissions regulations..

thumper64

You won't need as much fuel if you aren't moving as much air, so why would you want to dump excess fuel in? It would certainly be a good idea, especially if you really do want to burn less fuel.

You should look into adding a diffuser and smooth hub caps and such. Things like that can improve your mileage without making the car a complete dog. Plus, they can be cheaper to do.

If you're serious about the motor part, get the 96 spec D15B with 3 stage VTEC and figure out a way to run that. Or get a VX motor.

Jimster480

yea a 3 stage VTEC head swap would be interesting. he could run it with a programmed ECU. Or he could swap a Y5 head on there. And you can get better mileage with a cold air intake, and a heat shielding intake manifold gasket, and some E3 plugs. Since the intake charge is cooler, it needs less fuel. And the E3 plugs are more efficient about combusting the mixture, which also requires less fuel. It will also make the car a little faster, but since you dont care about that it doesnt matter, but you will get better mileage.

fleabag

That's what I was wondering, I mean would I need an ECU re-tune if I put a less aggressive cam on because there would be better cylinder filling at the lower RPMs than there was with the stock cams? It's not that I would put more fuel, I'm just concerned about whether or not the fuel mixture would become overly rich or overly lean with a less aggressive cam. I know for certain that putting a more aggressive cam on would create an issue at high rpms because there is more air-flow and therefore more fuel needed but I'm not sure sure about the lower RPMs..

What do you guys think?

CivicSpoon

Just because the person who wrote that little article didn't mention any ECU (fuel & ignition timing map) changes, doesn't mean they didn't do any. You'll certainly have to get engine management, as well as get the car tuned. There's absolutely no doubt about that. If you don't get the car tuned, then you'd be running rich and your timing maps would be way off; meaning you'll be running very rich & negating any fuel economy goals you're trying to achieve. And forget about high RPMs, you're not going to be making power anywhere close to stock redline. You're also talking about going from using 16 valves, to only using 12 valves, which isn't what the article is talking about.

Basically, there is far more involved than what you realize. It's also going to be far more expensive than it's going to be worth. You'll be paying for a custom camshaft, paying that cam company to figure out the specs of the cam that will actually work, engine management (chipped ECU and a free program at the cheapest), and then paying a professional tuner to tune you're car for you. All in all, you'd be better off doing an engine swap to an economy VTEC engine. Or another option would be to get a chipped ECU (with engine management) and have a legit tuner tune your stock engine for fuel economy over performance. A tuner who knows what they are doing, other than just being able to tune for WOT, should be able to squeeze out quite a few more MPG out of a stock D16Y7.

Jimster480

Well see you cant put a VX or HX cam into your head since they are both VTEC-E and your head is not VTEC. So you would need a custom ground cam or a VTEC head swap.

fleabag

Here is the guy discussing the cam swap:
http://ecomodder.com/forum/showthrea...leted-102.html

Here is what he says: "Won't the car also need an XFi computer?

No. It's a mechanical thing: the different cam profile - lower lift & duration - raises the cylinder pressure and shifts the torque peak downwards, so less throttle is required at low RPM.

It lowers the XFi's HP rating from 55 to 49, but the torque value is unchanged (the RPM at which the max occurs is lower). (EDIT: The cam alone may not be the HP limiting factor - that could be ECU-related.)

A number of people have done similar swaps including GeoMetry on this forum, and 3 that I know of on teamswift.net. I don't think any of them also swapped ECUs"

CivicSpoon

You're talking about apples and oranges here. That article is talking about just using a less aggressive cam, it's not talking about using a cam that will only open a certain amount of valves. Now if you forget about the whole VTEC-E thing ("turning off" 4 valves), and simply had a custom camshaft made, it'd be easier to do. But you'd still need to get a chipped ECU and a tune, to get the most benefits out of it. If you don't then all that work would be pointless. Even those Geo Metro guys would see an increase in MPG if they had proper engine management and had it tuned.

fleabag

Well the whole point of "turning off 4 valves" is so that the engine can reduce the airflow to that of a 2 valve engine while promoting better swirl. Also it doesn't really close the 4 valves entirely, just barely enough to allow fuel through so that it doesn't collect behind the valve. It's not hard to imagine a D16Y7 having cams that matched the D15Z1/D16Y5.. Just remember that with out the vtec lobe engaged (it's another lobe) the D16Y5 and D15Z1's stock valve profile actually calls for 12 valves to open and close and to get the whole 16 valves to open and close, VTEC has to be engaged.. So you just copy the cam profile, ignoring the vtec cams... right?

Jimster480

well yes, but you cant do that permanently. Otherwise the engine will choke after around 3500rpm.

fleabag

Well, you'd just accept that as an attribute of the engine, that you can't drive faster than 3500rpm.. I think one could reasonably drive around without ever exceeding that.

Jimster480

that would suck

Red_Army

your talking about making an entire new car basically and one you can't ever have fun in.

my friends bmw only goes to 4500. and since youd have to get it retuned you could just buzzkill redline it at 3500. and thats only resonable on a D. my car shifts past 3500 for normal driving.

just retune the one your using as said before for mpg not WOT. and drive better. i can get a 4ish mpg difference just by driving nicer. i realize this is what YOU want but sometimes ideas are best left as ideas.

Jimster480

and like I said before if you really want MPG then swap a HX or VX engine or do a HX head swap and get it tuned.