Blackfly XFi? Geo Metro economy cam shaft swap! Update: swap completed

[gogogeo]

Has anyone done the cam swap but still have the 12" tires? What will that do for your mpg? Thanks, Craig

[Frederick]

I doubt that anybody still has the 12's
I installed 13's with the same diameter overall. The MPG should be the same.

[gogogeo]

Mine is an Lsi. Just wondering how much it would change the FE if I just did the cam swap and not the tires or trans. Thanks

[Frederick]

You will gain a little.
I did not change the tranny in mine, just the final gear. I had to mill 15thou on the face and that was it. I have been saving fuel since then. Quite important these days as fuel prices in Quebec have skyrocketed to 1.45 a liter or about $6.00 a gallon.
Of course the gvnmt. is mighty happy. Taxes are on the total price not by liter.

[wmjinman]

Does anyone know if there's an "economy cam" like this available for the 4 cylinder engine - since I'm working on mine? It's the 1.3 liter engine in a '99 Swift.
Thanks,
Bill

[MetroMPG]

Good question. I wonder if the 3 cyl and 4 cyl SOHC used the same cam profile. If so, you could get an economy grind done from a 4 cyl cam.

I can tell you will probably know: Mike at 3-Tech performance: http://www.teamswift.net/3tech/

[wmjinman]

Well, it looks like this question is definitely for real, now.... The mechanic had my car up & running and was about to call me to come get it when it died. Guess some oil passages got blocked somehow, and 3 cam bearings went out. He thinks the machine shop did it during the valve job. Need to replace the cam and some other stuff now. - dammit -

so - e-mailing "3tech" now...

[undeRGRound]

Good overall Cam Swap posting! Nice site. MetroMPG!

The only thing here I see that makes an incorrect assertion is where it is stated that "the smaller lift and duration" is what makes the lower RPM cylinder pressure and torque increase. Generally, it has been found that higher lift will increase torque and HP without losing any low-RPM torque, and sometimes below-peak torque is also enhanced.

I'd like to think I could get a custom regrind based on a regular 3 cylinder cam that could handily beat an XFI cam in MPG, Torque AND Horsepower, but the HP might take internal engine mods. OEM engines are so far from optimized that a dedicated builder can easily make all aspects better with a little hard work and research. A great book (now out of print) Practical Gas Flow, by Dalton.

There is ONE Outstanding cam spec that determines engine responsiveness, torque and HP more than any other, can anyone guess what that is?

Lift?

Duration?

Ramp Rate?

Lobe Style?

...or something else?

[Ecky]

Originally Posted by undeRGRound

Good overall Cam Swap posting! Nice site. MetroMPG!

The only thing here I see that makes an incorrect assertion is where it is stated that "the smaller lift and duration" is what makes the lower RPM cylinder pressure and torque increase. Generally, it has been found that higher lift will increase torque and HP without losing any low-RPM torque, and sometimes below-peak torque is also enhanced.

I'd like to think I could get a custom regrind based on a regular 3 cylinder cam that could handily beat an XFI cam in MPG, Torque AND Horsepower, but the HP might take internal engine mods. OEM engines are so far from optimized that a dedicated builder can easily make all aspects better with a little hard work and research. A great book (now out of print) Practical Gas Flow, by Dalton.

There is ONE Outstanding cam spec that determines engine responsiveness, torque and HP more than any other, can anyone guess what that is?

Lift?

Duration?

Ramp Rate?

Lobe Style?

...or something else?

I'm not too terribly informed about cam profiles, but lower lift duration should (to a point) move peak torque lower in the RPM band, where almost everyone on this site drives, right?



Also, I'm willing to bet there isn't a better cam that could be made for my car. It seems Honda gave their engineers leave to go all-out for the first-gen Insight.

EDIT: Welcome to the forum!

[Cobb]

3tech will give any cam an economy or "xfi" grind. Ive asked about my insight. Plan B was to give the vtec a wild grind, but I hear the gen 2 insight may have flat lobes on the vtec profile.