Engine modding question

[Jorge89]

I have a 1994 civic ex 4dr with a d16 engine in it. I was wondering if putting lightweight parts would make a noticeable difference in mileage. I was thinking about a lightweight gear cam and a lightweight flywheel. I've read that lightweight crank pulleys can be bad since they vibrate too much so I don't think I'll change that one.

When I was 16 I changed the flywheel in my 1995 civic 2dr for a lightweight one and could feel the difference in acceleration, but I'm not sure if it made a difference on the mileage since I didn't care about that back then. Has anyone tested this?

[oil pan 4]

Unless its pure city driving then no chance.

[UltArc]

Realistically, yes. It will definitely make a difference. Whenever there is less mass, it will take less force to move it.

Here, it is rotational force. I do not know exacts, but it is usually approximated at 4x the force for rotational vs stationary weight.

The question is if its worth it for the difference. Personal Experience: My drive shaft is 39 lbs. A single piece aluminum is 27. A carbon fiber single is 16. I do not NEED a new one, single aluminum is 600, CF is 1000+.

Its not more power, its just less of a parasitic loss- aka, less engine work needed to move that extra weight.

So yes, you should see gains- but how much, and if it is worthwhile takes more calculating.
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If I were in your shoes, I would wait until it was needed, or wait until other work was needed, and start a little fund for the parts. A few bucks per pay check, or whenever you buy something put the change in a jar, or like me, I don't spend singles- anything smaller than a five gets saved for holidays.

But for some people fuel economy is not just a fun hobby, but needed to save money. If this is JUST for saving money, keep in mind you can get t boned tomorrow, and all of your work could be valueless. Fun? Go for it! To save money? Calculate.

[Jorge89]

Originally Posted by oil pan 4

Unless its pure city driving then no chance.

Most of my driving is done in the city so I rarely drive in the highway.

I'm not really doing this to save money. I like to work on cars and improve things. I'd like to see how many mpg I can make my car get. That said I can't be throwing money around either. I might just go with an Anodized Aluminum Bolt-on Cam Gear and a lightweight flywheel from ebay which would only cost me $36 and $130 respectively.

[mikeyjd]

If you have short commutes, you might want to look into going alternatorless to save 10-15% fuel.

[UltArc]

Originally Posted by Jorge89

Most of my driving is done in the city so I rarely drive in the highway.

I'm not really doing this to save money. I like to work on cars and improve things. I'd like to see how many mpg I can make my car get. That said I can't be throwing money around either. I might just go with an Anodized Aluminum Bolt-on Cam Gear and a lightweight flywheel from ebay which would only cost me $36 and $130 respectively.

For me, that would be something I would jump on and do it. Parts for me are much more expensive!

[Jorge89]

Originally Posted by mikeyjd

If you have short commutes, you might want to look into going alternatorless to save 10-15% fuel.

I was looking into that since I drive less than 10 miles a day. I'm going to make a solar panel for the roof of the car so the battery can charge a bit while the car is parked.

[02ws6]

Id look into getting some OEM parts for the durability. The d15z1 came with a lighter flywheel and crank pulley if im not mistaken. Im kinda suprised noone has tried running the z1 head with vitara pistons for the valve clearance. I have a spare head I may try it with when I finish my other two cars.

[California98Civic]

I drive a 1998 DX that I have taken about 230 lbs out of it. One guy on here claims that articles generally cite 2% FE gain per hundred pounds reduction. By that measure, I should be close to a 5% gain from weight reduction alone. And like aero mods and speed, what you do for weight will help acceleration if you want it. Win/win. My garage page for this car details tons of things I've done. PM me if you like. I'll reply.

[cRiPpLe_rOoStEr]

If you had to rebuild your engine soon, the extra cost of aftermarket lightweight parts would be easier to justify. But they do benefit both performance and fuel-efficiency, and are worth.