Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features: Join our community! |
| Tofuball's '94 XFi; It's all about city MPG | |
|---|---|
| Tweet Topic Started: Mar 12 2011, 08:59 AM (39,442 Views) | |
| Tofuball | Apr 16 2011, 12:11 PM Post #106 |
|
Strange Mechanic
![]()
|
Crazy busy. Head still in shop. Finally had some time to work on the Geo, changed trans fluid with synchromesh. Noticed I have a fluid leak from the seal for the passenger side half shaft. Also noticed I have an exhaust leak behind the cat, and the exhaust hits my front swaybar (yay!). I advanced the cam gear one tooth past the line and retimed the ignition back to 8 degrees. According to MPGuino I'm getting 50mpg combined now. I definitely have much more low end power and vac flutter has been cut in half. Debating advancing it another tooth to see if vac flutter goes away entirely. |
![]() |
|
| Woodie | Apr 17 2011, 06:05 AM Post #107 |
![]()
|
Something wrong there, one tooth is 18° or so, way too much to just move it around without making a huge difference in driveability, |
![]() |
|
| Tofuball | Apr 17 2011, 08:32 AM Post #108 |
|
Strange Mechanic
![]()
|
I consider +10MPG, greatly reduced flutter, and way more low end to be a pretty huge difference
|
![]() |
|
| Tofuball | Apr 17 2011, 09:12 AM Post #109 |
|
Strange Mechanic
![]()
|
Any idea what could cause this? Since currently I can only adjust it by the tooth for now, or "by ear" if I make an adjustable cam gear, I'd really like to just get it "right"
|
![]() |
|
| mcmancuso | Apr 17 2011, 10:55 AM Post #110 |
![]()
|
mwebb has noticed that advancing 10 or more(cam timing) with the econo-cam traps some of the combustion mix in the chamber, not ideal for power, but may be additionally beneficial for reducing the volume of fresh charge entering the cylinder which reduces the effective volume of the engine, that, in some cases, can result in better FE. If you had valve flutter and lousy low end power, you were off by a tooth on the cam gear, moving the timing one tooth one way or the other from proper position will result in a working, but not spectacular, engine. More than 1 tooth will usually keep it from running. Sounds like your current location is correct. Where is the distributor in its adjustment with it at 8°? if its near the center of its potential movement you definitely have it correct now, and it was off a tooth the way you had it. Typically when someone installs a cam off by a tooth, the distributor ends up near the end of the adjustment groove to time it correctly. |
![]() |
|
| Tofuball | Apr 19 2011, 07:10 PM Post #111 |
|
Strange Mechanic
![]()
|
Good info, thanks. The more I think about it the more I bet something is up with the CRANK wheel side of things . . . somehow. I have to resolve this before I can get a baseline and plug my Megasquirt in! I have all the parts for almost all of my plans, but without a baseline, I can't brag about gains! Head is still in the shop. Allright, since you guys love pictures so much, here are a few random ones: Two weeks ago or so I cleaned up the TB, cut a lot of material off, when I got the TB the screws were stripped. Even in a max MPG setup, I recommend replacing those screws with set screws as it cuts down on turbulence where you really don't want it. ![]() Also, I painted my hubcaps because they looked like crap. BEFORE: ![]() DURING (sanding): ![]() AFTER:
|
![]() |
|
| dayle1960 | Apr 19 2011, 07:47 PM Post #112 |
|
Fastest Hampster EVER
![]()
|
Wow, what a difference on the hubcaps. Good work so far.
|
![]() |
|
| bogs | Apr 20 2011, 02:18 AM Post #113 |
|
Duct tape heals all wounds
![]()
|
Very well done
|
![]() |
|
| Tofuball | Apr 21 2011, 10:52 PM Post #114 |
|
Strange Mechanic
![]()
|
Tonight I cut the throttle body up (cut off the cold start) and put an epoxy plug in it. Once that dries I'm going to sand it all down, polish the bore and paint it. Then reinstall the butterfly with set screws and all the accessories. Edited by Tofuball, Apr 21 2011, 10:53 PM.
|
![]() |
|
| Metro Fanatic | Apr 23 2011, 08:21 PM Post #115 |
![]()
|
Good progress. Nice looking hubs....way better curb appeal I bet! |
![]() |
|
| Tofuball | Apr 23 2011, 10:35 PM Post #116 |
|
Strange Mechanic
![]()
|
On the right, a nice clean and painted TB.![]() On the left, weight savings. Whats the effect of running without a dashpot? It lets the throttle slam shut, so it's easier to shoot flames out a catless exhaust . . . |
![]() |
|
| Tofuball | Apr 23 2011, 10:36 PM Post #117 |
|
Strange Mechanic
![]()
|
Thanks
|
![]() |
|
| Coche Blanco | Apr 24 2011, 12:12 AM Post #118 |
|
Troll Certified
![]()
|
...really? My interest is...sparked...
|
![]() |
|
| Tofuball | Apr 24 2011, 04:53 PM Post #119 |
|
Strange Mechanic
![]()
|
The cat works as a flame arrestor. Without it flames can travel all the way from your combustion chamber to a tailgater near you! |
![]() |
|
| mcmancuso | Apr 24 2011, 10:44 PM Post #120 |
![]()
|
|
![]() |
|
| 1 user reading this topic (1 Guest and 0 Anonymous) | |
| Go to Next Page | |
| « Previous Topic · Project Forum · Next Topic » |


Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.









7:24 PM Jul 10