Project: The AeroFocus

[MetroMPG]

Yes. I've yet to see a car that doesn't get better fuel economy by "upshifting".

[arcosine]

Originally Posted by HydroJim

1/12th the radiator size seems to be what I have.

currently my car runs in the middle of my BSFC map at highway speeds, but would it still be advantageous to run 20% lower RPM's?

I doubt this very much that it is on the peak, 3/4 throttle at 2500 rpm? I would say that is is well off to the side near 15 hp.

See on the lower map following the constant 30 kw curve, at 3000 rpm to 2400 rpm sbfc goes from .3 to .26 a 15% improvement.

[HydroJim]

This is good information. Definitely something I will take into consideration when I'm rebuilding my transmission.

Any guess what kind of MPG improvement I would get, or is it pretty random?

[MetroMPG]

It's going to vary from engine to engine. But I reduced cruising RPM by ~26%. MPG went up by ~5%.

Project 'nerd gear': taller tranny transplant nets +5.2% MPG - MetroMPG.com



Metro taller transmission swap thread: +5% efficiency gain (taller final drive) - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com

That's enough of a boost that I picked up another transaxle with the same taller final drive that one day ( ) I will put in the convertible. (One of these years I'll get around to fixing it up & putting it on the road).

[arcosine]

The lower fuel consumption map is for a Mercedes, The Focus will have a different road load. The top map is the Ztec engine. You can see why pulse and glide works, accelerate near the peak bsfc and then turn engine off. What engine speed is Aerofocus at on the highway? For the upper map brake torque times engine speed equals power, 3000 rpm at 60 Nm is the same hp as 1500 rpm at 120 Nm.

[Allch Chcar]

Originally Posted by arcosine

You are right they don't bolt up.

Its cool that the final drive can be changed , in the Saturn it is integral with the shaft. If I could only change to a 3.42:1 from the 4.025:1!

Do all Duratec engines have the same bolt patten?

[IMG]

ZTECH:
[IMG]
SOHC:
[IMG]

Nice find. But yes the Duratec, like Ford engines share bolt patterns for a given family. Eg a Duratec engine will bolt up to any Duratec transmission. But the Zetec and Duratec have different bolt patterns.

[euromodder]

Originally Posted by HydroJim

So if I rebuild my MTX-75, I could potentially swap in a taller 5th gear and a smaller final drive?

Volvo did likewise on the Drive models of the 1.6D engine, all versions of which use the MTX75 transmission.
Lengthening the top gears (4 and 5 , and the final drive as well IIRC) so the rpm dropped considerably at speed.

Threat it well, 'cause these (Ford) transmissions don't have the best of reputations over here .

[HydroJim]

I've been pretty busy with school and work lately, but here is what I've gotten done:

I re-did the rear wheel skirts. Should provide better flow and they look much better.



My buddy came but to give the car a quick photoshoot:






I will be taking a trip down the clarksville, Tennessee during thanksgiving break where I will be replacing my transmission. I am hoping to get there (550 miles) on one tank(13.2 gallons).

[Gealii]

so that be about 42mpg seems very doable in ur focus, hope you do it.

[HydroJim]

Originally Posted by Gealii

so that be about 42mpg seems very doable in ur focus, hope you do it.

Not sure if I would want to risk running the tank dry so assuming I use 11.2 gallons before I fill up, it would be closer to 50 MPG which is a pretty good goal because I have not yet surpassed that milestone