Firefly Conv gets an XFI Camshaft - Fuel Economy, Hypermiling, EcoModding News and Forum

canhonkey · 11-17-2008, 09:43 PM

Was over to see Mike (superfly) from TeamSwift on the weekend.

My 91 Firefly Conv now has an XFI'd econo cam. I installed it this afternoon, didn't take very long. The cam looked like brand new, Mike does a really nice job on these. Car def has more torque between 2-3k rpm, and this cam has shifted the power down making it more usable. Still is a

though! But expected haha!

My next mod will be to acquire a Tranny in good condn. I'd like one with a 3.79:1 final drive ..according to this link I'd find that on a 98-01 4 cyl metro, firefly?...anyone? 3.52 is probably a lil extreme for us since the wife mainly drives highway 110kph.

http://ecomodder.com/forum/showthrea...sion-2988.html

I was getting 40-41 US Mpg prior to this mod, so I'll post new readings when I have em

Ken

SVOboy · 11-18-2008, 12:50 AM

big time

canhonkey · 11-23-2008, 04:37 PM

Thanks!

Got 39 US Mpg this time, but we've had a big temp drop this week. Snowed last weekend and hasn't let up since, averaging -5C. That and I've been tuning the car and putting new belts and not to mention letting it warm up for 5-10 mins every morning, so its been doing alot of idling. On top of the short runs in cold weather..which isn't good for fuel economy.

The power band has definetely shifted down, the power seems to be more from 2500-3500rpm. More usable, I also found a tranny out of a 95 Swift SOHC 1.3L, that I'll be swapping in for 100 bucks. That'll lower the final drive ratio from the sky high 4.39 to 3.52 or 3.95, whichever is in it..either way it'll be a big help because right now she's reving at 3500-3600 at 110kph! Prob end up doing that later next week.

I'll pass on next fills details, cheers for now

Ken

MetroMPG · 11-23-2008, 05:19 PM

Good update, Ken.

Get yourself a good block heater and stop idling! It'll probably save you as much fuel as the transmission swap will, plus it's nicer for the engine.

Also: note that after the swap, you'll have to do a correction to your odometer readings to calculate MPG on a level playing field. The speedo gear in that transmission will likely be different from the one in the original tranny.

So, before you do the swap, do a very precise measurement of Point A to Point B with the current transmission so you can repeat it and figure out the difference after the swap.

metroschultz · 11-23-2008, 10:31 PM

No worries on the speedo Darin,
The speedo gear is on the end of the cable.
It plugs into the trans on the output side.
Directly connected to the right side axle.
Final drive ratio does not affect speedo reading.
Schultz

canhonkey · 11-27-2008, 04:57 PM

Quote:

Originally Posted by MetroMPG

Get yourself a good block heater and stop idling! It'll probably save you as much fuel as the transmission swap will, plus it's nicer for the engine.

Still no block heater..I was going to do a Kat's combo of 200W magnetic heater for the tranny oil and the Circulating tank heater for the block..ordering it from online would be about 80 bucks shipped..

Quote:

Originally Posted by metroschultz

No worries on the speedo Darin,
The speedo gear is on the end of the cable.
It plugs into the trans on the output side.
Directly connected to the right side axle.
Final drive ratio does not affect speedo reading.
Schultz

To see how much my speedo is out, I've just been using a GPS and working out a % difference..its about 8% right now.

Our last fill was a little disapointing, 41 US Mpg. I'm not sure why it won't improve (probably the cold weather!) But I can't seem to break the 43 US Mpg mark. Both of us have been driving conservatively, save for the 110kph cruise on the hwy. My guess is the 4.39 final drive tranny really isn't really helping matters

I mean, its a metro, it should be kickin ass in FE!

Hopefully I'll swap that tranny out next week, this week fell through

Ken

MetroMPG · 11-27-2008, 05:38 PM

Ken: these cars do NOT do well over 100 km/h.

In fact, the mileage you're getting is pretty much what I would have predicted at that speed based on my own futzing around:

Source: http://metrompg.com/posts/speed-vs-mpg.htm

Note that this was taken in warm conditions, pre-XFi cam and pre-Swift transmission. The fact you're getting 43 mpg (US) in the cold, at those speeds in a heavier, less aerodynamic (probably) convertible, tells me your mods are helping.

canhonkey · 11-27-2008, 07:52 PM

Quote:

Originally Posted by MetroMPG

Ken: these cars do NOT do well over 100 km/h.

In fact, the mileage you're getting is pretty much what I would have predicted at that speed based on my own futzing around:

Source: Speed kills: testing MPH vs. MPG in top gear - MetroMPG.com

Note that this was taken in warm conditions, pre-XFi cam and pre-Swift transmission. The fact you're getting 43 mpg (US) in the cold, at those speeds in a heavier, less aerodynamic (probably) convertible, tells me your mods are helping.

Wow, that graph sure puts it in perspective!! (excellent work)

43 was our best in warm weather(sans XFI cam), on the last tank with XFI Cam we got 39-40mpg, in Temps -5 to 0C. With the top up and the extra 150lbs, I can't see it being that much less aerodynamic..its a pretty sleek little rig. But I have no way of confirming this. So from your graph, if we extrapolate, the FE we're getting is as expected.. around 40 US Mpg at 110kph..eh? (Especially with that conv tranny! Grrr)

Well that is re-assuring though, though we'll keep pressing for better. I'll be sure to post more updates on the car

Ken

me and my metro · 11-27-2008, 09:07 PM

My 95 trans came with 3.79 gears. Be careful when you change the trans. I am changing the heater core this weekend because when I changed the trans I let the engine settle to far and it pulled on the heater hose. I love my xfi cam and 10 degree gear. This combo works well in my heavy sedan. 50 mpg in cold weather, I just cruise about 55 mph. Cheers