Ecomodding my winter beater: a unicorn no-rust (*) 2000 Chevrolet Metro 1.0 5-spd

[gone-ot]

Originally Posted by MetroMPG

Splitter!



...just kidding.

More to come.

Uh, wouldn't putting a "splitter" on that vehicle be similar to putting "racing stripes" and "tail fin" on a turtle(*)?



(*) No offense intended to turtles.

[freebeard]

(*) No offense intended to turtles.

You missed a rare opportunity to use the

Technically correct is the best kind. Forget teh posers.

Adding a front wall for an air dam will gain almost nothing. Unless it is convex to add a bellmouth to the lower valance. However, add an artfully shaped (per aerohead) shark-fin to each outer end and you can create an air curtain that will throw a flat jet of fast air over the front wheel opening. It would be a convergent duct aimed somewhere between the outer edge of the tread and the sidewall.

[MetroMPG]

The "splitter" (*) was actually the structural part behind this cow-catcher/snowplow:





~3.5 inches of clearance. It scrapes once in a while.

It is a more durable version of this project, first tested on the Firefly in 2009:



http://ecomodder.com/forum/showthrea...ly-b-9732.html

* - a small splitter may actually help reduce drag on an air dam like this, in some cases. A CFD analysis of a similar air dam applied to a 1st gen Miata showed a slight improvement (and slightly reduced front lift).

[MetroMPG]

Originally Posted by freebeard

an artfully shaped (per aerohead) shark-fin to each outer end and you can create an air curtain that will throw a flat jet of fast air over the front wheel opening. It would be a convergent duct aimed somewhere between the outer edge of the tread and the sidewall.

Air curtain would be fun to make. I'm still adding the crude mods to the car though. Walk before run.

We know ducted air curtains work. They're showing up on more and more conventional vehicles. The trouble with DIYing stuff like that is I bet the improvement is relatively small, which makes it hard (without a wind tunnel) to know if you made things slightly better, worse ... or no change.

[MetroMPG]

What you see here is the result of an XFi camshaft-ectomy, freshly performed on the Firefly (and also its stock, garden variety camshaft).

It's not too big a job to pull a cam out of these motors, so I'm swapping it over to the Metro.

I'm doing it the "easy" way, having cut the tops of the timing belt covers of both cars with a dremel to expose just the cam gear. Otherwise, to get the belt cover off, you have to remove the crankshaft AND waterpump pulleys.

The "easy" way leaves the timing belt in place, while you delicately slip the belt off the cam gear once the cam is loose.

The risk of doing it this way is: what happens if the timing belt slips/jumps on the crank gear while the cam is out of the engine or while you're messing around trying to get the belt on/off? It turns into a bigger job, that's what happens.

[MetroMPG]

Amazing: I just looked up the thread where I first swapped this very XFi cam into the Firefly, which was posted to this very Internet Forum, 10 years and 2 days ago:

http://ecomodder.com/forum/showthrea...2.html#post968

[MetroMPG]

It's in, buttoned up & runs great!

I love the character the XFi cam gives the engine. 5th gear is usable for cruising at around-town speeds now, where the engine wouldn't have been happy doing it before.

One thing I didin't recall from the first time I did this swap:

The engine did NOT want to start afterward. The first 3 times I turned the key, it spun really fast, almost as though there was no compression.

The 4th time it caught, but ran really rough -- was sure I must have jumped a cog on the crank gear when I was messing with the timing belt.

The 5th time, it ran less rough, then smoothed out after about 30 seconds.

I wonder if the lifters were messed up from being depressurized?

Maybe the fast spinning at first wasn't a lack of compression (obviously), but with if no valves were opening at first, the cylinders were just being air springs?

[iikhod]

About the timing belt cover...are you going to leave it open like that?

Would be convenient to put some sort of quick-open system for example checking the timing belt with little work.

[MetroMPG]

I reinstalled the top portion of the cover.

But it's only held on by two 10mm bolts, so it's easy to remove to inspect the belt and/or swap camshafts again.

[Stubby79]

Originally Posted by MetroMPG

It's in, buttoned up & runs great!

I love the character the XFi cam gives the engine. 5th gear is usable for cruising at around-town speeds now, where the engine wouldn't have been happy doing it before.

One thing I didin't recall from the first time I did this swap:

The engine did NOT want to start afterward. The first 3 times I turned the key, it spun really fast, almost as though there was no compression.

The 4th time it caught, but ran really rough -- was sure I must have jumped a cog on the crank gear when I was messing with the timing belt.

The 5th time, it ran less rough, then smoothed out after about 30 seconds.

I wonder if the lifters were messed up from being depressurized?

Maybe the fast spinning at first wasn't a lack of compression (obviously), but with if no valves were opening at first, the cylinders were just being air springs?

I did the same thing. Drove me nuts, thinking I screwed the whole thing up!

I posted on GMF...immediate answer was that my lifters had extended up without the camshaft to hold them down, and basically over-filled themselves hydraulically. Just had to wait for them to bleed back down to normal.

Oops! Should have thought of that!