Old Hatchback Modifications

I am listing all the mods done to the car while it was still a hatchback. Some of the modifications have linked pages showing more detail but a lot of these mods don’t need much of an explanation. This list was my basic starting point on this car. Some of these mods are no longer needed on the new rebuilt convertible body but this list is still useful for anyone not wanting to go to the extremes with the mods on their car.

Note this page is way out of date

I have not listed the major list of modifications done throughout my Convertible XFI project. I have written a page with a complete list of modifications I think most people who own these cars would be interested in. I have done a lot of them but not all. I have tried to list every modification I could think of.

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  1. I have not heard anybody say anything about underdrive pulleys for the crankshaft and alternator. Have you tried that yet?

  2. Can get a 25% underdrive for the crankshaft on suzukird.com. It is supposed to help mileage and power I just haven’t gotten around to getting one yet. Now with the Convertible XFi buildup going on I probably won’t have time to get one and test it out good till fall. So I have no idea of the actual gain from an underdrive pulley but sooner or later I will get one and test it out. I will report it here when I figure out what good it is.

  3. How did you get Megasquirt to work on a 3 cylinder? Did you use an EDIS 6 and only use half the cylinders? I have wanted to use MS on a Turbo G10 engine I have from out of a 88 Turbo Sprint but didn’t think you could. Please elaborate a little on how you did that. Thanks, Jason

  4. On the cars with a computer control ignition you can let the megasquirt control the ignition directly. Just look in the megasquirt manual on how to wire up a 7 pin HEI module to get any ignition to work. Everything else except the idle air control valve works just fine with it. I will probably do a detailed writeup once I get the car to a dyno and get a perfect spark map for it. Using a knock sensor you can get it close but not exact so once that is done I will post my tune and everything on here.

  5. Congratulations on your incredible fuel savings! I bought myself a Metro with the hopes of getting some high numbers too! My plan is to remove the alternator and run an electric motor to run the water pump with a deep cycle battery. I put in synthetic gear oil in the trans as I see you have done, but all my research seems to differ on what is best. The most popular seems to be GM Synchromesh. I notice you saying synthetic Dextron III is better. I haven’t seen that metioned before. Could you elaborate on that? One concern I have is longevity, and I fear a thinner fluid, while providing less resistance, may be a poor choice for long term use. Thanks for a wonderful website!

  6. Synchromesh is slightly better than syn Dextron III but it is harder to find and more expensive. I don’t think there is a big difference between them in a metro transmission though. The transmissions half the time came with ATF in them from the factory and GM is the one that said use gear oil. Suzuki recommends ATF, since they built the car I figure they would know what works. I am looking for a transmission with the 3.54 gear ratio and if I find one I will put Dextron III in it when I do the swap.

  7. Hi Rick, A friend just told me about this site. I am an old gear head. I have done alot of what you have done. Long before I found this sight. I seems to be working. I am interested in more details about the engine. When you cut the head did you also bore it? Are you running a long tube header? And if so where can I get one? I have been planning on making my own. Also you talked about cam timing. Are you changing the cam timing with off set keys? Or is it like the old Datsun’s where you had a choice of where to line up the sprocket? Also if you bored this block where do you find forged pistons. I am new to the internet. And computers. I am sure I will have more questions later. Thanx

  8. I have not bored the engine. It is running the stock pistons. I shaved the head a bit more than is actually good. If I would have shaved it 0.020 instead of 40 it would have been much better. The way it is now it is hard to keep it from knocking.

    To adjust the cam you have to drill a new hole in the sprocket. I drilled several holes so I could adjust the timing to pretty much anything I need. Advancing the cam will help pretty much any engine improve bottom end power. This will help it get better mileage by being able to shift gears earlier and being able to drive at lower rpms at slow speeds.

  9. Literally–radical. I give you much respect and a little envy. Now my questions, there is a lot of conflict about whether the tornado air spinner device actually helps. Some prominent people (that sell them) say that beyond what is advertized the greater benefit is in initial tip in of the throttle. Now this can’t be measured on the dyno so it’s unreported. My personal feeling is that how could it help before the throttle and if it can (theoretically it sounds correct)why not put “in” the manifold or even individually in the intake runners due to the classic problem of the butterfly valve disrupting incoming air. Along the same lines, do you think it is more beneficial at higher rpm or lower and what about for the exhaust track?

  10. I have the option of buying a metro XFI wireing harness and ECU ( $150). Do you think I should buy this? I can just purchase the ECU alone for $70. Will this work, does it need the harness, or is it that the ecu, is the only difference from stock electrical parts? If I have the cams ground and the ECU and harness does this mean I now have a XFI ? Also, my metro’s (a base model 3dr. 3 clyinder manual) tranny is stock. Is it worth parts scavenging for the taller gear? Why could’nt I use taller wheels? What models have this gear or have one that could fit with a little machineing? Thanks for your help.

  11. Knife-edged crank, light wieght alloy pistons and rods, ballanced rotating assembly, modified to smaller crank journals ? Are these in your future or do you even think they are practical or worthwhile for someone else??

  12. The tornado isn’t going to help anything. Nobody who has tried one has had success unless they are also selling them. With any fuel injected car there is no benefit to the air being turbulent flow.

    The XFi computer is pretty much the same tune as the stock computer, it has a bit more ignition timing on the bottom end from what I can tell. It is just a small difference to take advantage of the xfi cam. If it was me I would not bother crawling under the dash to change them even if I had them. The cam and transmission gears are probably 90% of what gives the XFi better mileage than the base metro. So those will be your biggest gains. Everything else will help but some things will take a huge amount of effort for a tiny gain so it all comes down to what getting really high numbers are worth to you.

  13. I have a 1990 firefly 4 door. So far I’ve increased the tire pressure, disabled the daytime running lights{keeps the alternator turned off more}, played with the O2 sensor, and added octane boost to make the timing advance. My best mileage so far has been 62.3 so there is room for improvement yet. Next is bigger 13 inch tires and maybe some aerodynamic mods. I go to the crushing yard a lot so most of the parts I use are used and very cheap or free even. I look at lots of O2 sensors and the ones that seem to work the best are ones with white tips. The light brown tips give more power it seems. I know that isn’t very scientific, but that’s what I’ve noticed. I bought this vehicle at a garage sale for $250 four years ago and its been lots of fun

  14. What is your curb weight before and after? And isn’t a convertible heavier that hatchback to start with?

  15. Hi Rick……..Is that a West Virginia inspection sticker I’m seeing ?
    If so I sure would like to visit and see your xfi up close and personal.
    I live about 10 miles east of Flatwoods and also have a Metro daily driver.
    I’ve read the about the megasquirt ever since it was written about in
    Car Craft several years ago and would loved to have gone to Atlanta this
    weekend to the DIY get together. Looks like Bowling, Grippo and many of
    the contributors of accessories were going to be there.
    I would really like to know if replacing the throttle body injector with
    separate injectors for each cylinder and putting an oxygen sensor in each
    exhaust pipe would be worth all the time and trouble. Or should I find
    another metro and go the electric route. I’d better hurry up and decide.
    I’m not getting any younger and rolling around under a car sure leaves
    me sore the next week.
    This is more of a personal post to you but I couldn’t find a “contact me”
    link on any of your sites.
    Thanks, Gordon

  16. Added a contact info link on here :)

    Yep I live at Kistler, WV so it isn’t that far away from you. Right now the car is in the middle of the XFi convertible rebuild but it should be running again in the next few weeks. So sometime this summer if you want to swing by and check it out that would be fine with me.

    I don’t know if replacing the throttle body with multiport will increase mileage much but changing out and going to coil on plug ignition is pretty much always better than using a distributor. That is not that hard to do using megasquirt. But the gains on a stock motor will be small. They are not tuned that great from the factory but they are reasonably close and there isn’t that much to be had over factory just by getting the tuning perfect.

  17. Hi does anyone know precisely what the fuel injection system problem is that cause’s high mileage metro’s to lose fuel efficiency and vibrate exessively at idle? My xfi has good compression, clean injector nozzil, new o2 sensor, correct timeing etc. but averages 46 mpg. Thanks

  18. Run flat top pistons with head clearance reduced to .03″ or less, compression ratios of 14 to 17 to one on 89 otain pump gas. The mean squish velocity out of flat squish areas ( like most normal layouts ) are dependent on the piston to head gap! The smaller the gap ~ Hasher the displacement out of the squish areas. This again is dependent on the density of the charge, aspect ratios of the combustion chamber based on the bore & stroke,exe. All production engine run about .06″
    clearance milling the head alone will not change it much.Dry fit the pistons into the block and check the
    clearance to the block deck. Each piston will be a little different. Have the block milled to bring the pistons to flat deck. Then Mill heads .04″.
    You should have a 3cylinder with 11 to 1 that can run on 87 octain.

  19. Doug, great insight! Could you elaborate more? For instance when you say dry fit, do you mean pistons bolted to rods to bolted on crank? Also “pistons being different”, is this in terms of thickness at the top between centerline of piston pin and top of piston? Which if this is the case would machineing the pistons be better? What would be the best way to describe what I want when bringing it to the shop for milling? Lastly, if I mill it down to .04″ what happens if I have to replace headgasket and need to mill for straightening?

  20. Does a jacob’s ignition or other distributor-less electronic systems justify thier high cost? Your thoughts?

  21. I don’t think you can get 11:1 compression ratio to work and still be able to run 87 octane. I am running 11.5 and I get knock sometimes. At most I would shave the head .020 off and bring the compression ratio up slightly over stock but it really isn’t worth it and I would just leave it alone if you want to keep running 87 octane without any knock. Raising the compression is good but having to retard the ignition because it is knocking kills any gains to be had from it.

    As far as the jacob’s ignition, the gain from it will take years of driving to pay off in gas savings. Just putting something simple like an MSD 5/6 on the car will make it start and run a lot smoother and is a lot cheaper. Any after market ignition is going to make it start easier and run smoother but probably not increase mileage enough to pay for itself. It is something you do if you want to increase mileage and not worry about the cost of doing it. I would recommend getting an MSD or similar box and hooking up, they make the car smoother and easier to pull out and drive at lower rpms.

  22. donovan, Dry fit= pistons, rods and crankshaft in block torqued without piston rings. Find true deck to pistons. Tell the shop that you want the piston as deck or above deck , to make up for the thickness of compressed gasket. We want .03 to .026″ between the flate are of head to piston at TDC with head on and head gasket in place. I have found big differences in deck to piston. From side to side as well as end to end.
    I do not want to make this out to be complex.
    The shop what is able to mill a head should be able to mill a block. This will not effect the head gasket at all. If one piston is lower than the other two the rod may be changed to make it more even/ mix and mach all in balance. I have changed a rod to make up .005 or so before. I would not mill on pistons because, it will make them weaker and change there mass. You may not need to push the compression ratio to its limits,but by fixing the squish areas to .03″ you will control ping like never before. When the head and piston are that close there is no combustion in that area, the electrons move into the metal surfaces. The air is forced out at extreem speed, improves combustion.
    Jagwire’s later V12 used Mays Fireball Combuston Chamber in prototype ran 17 to 1 compression ratio on 93 Octane. To get this type of compression ratio have the combustion chamber welded and recut into the fireball design? The Production model V12 Fireball has 11 to 1 and loved 87 Octane. I like the MSD 6+ and the MS II Injection computer awsome control.
    Remember that an electric Geo Metro stock body will run 60mph on 7500 watt hour. That is equal to 272 MPGe.
    70MPG is only 26% eff my goal is 65% or 175 MPG.
    “It is all cylinder pressure and leverage!”
    I am in the Progressive Automotive X Prize Competition.

  23. Rick, I am exploring the outerlimits,and noted here how to design, ping ,out of an engine. If the squish areas is larger than .03″ there will be a superfast flame frount in that space, if not controlled will detonate the cylinder charge///bang/ping/.
    Milling heads or higher compression pistons will not work well unless this is done right. This is the key for anyone that want to go there.

  24. Any tricks for getting better mpg on a ’93 with automatic transmission? Where can I get clear headlight covers? Thought about bigger wheels to change the ratio some.

  25. Hey Rick,
    Just thought I’d pass along my other XFI mods… simple E85 conversion.
    I’m in the Midwest where E85 is easy to buy. Have done only 2 mods to date but bumping the compression next is a big priority.
    Mod 1 was adding a fuel pressure gauge to monitor inlet pressure before the integral fuel pressure regulator.
    Mod 2 was making the FIXED factory fuel pressure regulator into an ADJUSTABLE regulator. Now, you can buy and adjustable regulator but the mod is so simple I went that route. Basically just added a bolt to the regulator cover that can adjust the force on the regulator spring and effectively increasing fuel pressure to the required level.
    You need a greater fuel flow for the E85 but since it’s cheaper you actually decrease your dollars per gallon while also decreasing your miles per gallon.
    This was phase 1 to be a proof of concept and she has perform flawlessly with nothing more than increased fuel pressure.
    With E85 octane in excess of 110 the next required mod is to measurably increase compression. Not sure yet what target compression ratio is most sensible and would listen to any advice offered.
    This project was done so far for a total of $12… the cost of the pressure gauge! Regulator mod cost zero other than about 2 hours building and adjusting for max performance.
    Needless to say I’m happy so far and expect to become happier after Phase 2.
    Keep those mods coming!

  26. I’d love to go the full-blown route with the Megasquirt, coils and exhaust but for now SIMPLE and CHEAP have been the plan on my project.
    It’s a great little car that I bought out of Virginia from eBay for $350.
    Drove it to Mich and gutted it out and made it a dedicated 2 seater. New paint, rally seats and new carpet then the E85 mods.
    25000 miles later I’m a happy boy :)

  27. Great ideas!
    But why not use the earlier and lighter 1989 body/doors?
    Also did you ever find a header, for the little 3 banger?
    And what is your mpg, after all your latest mods? I have a 1989 Geo Metro myself! And am in the process of also making a Aero/Metro 3 wheeled car, ( 1 wheel in front, 2 in rear)using the 1.0 and 5 spd. and a full tube frame. Less frontal area, less rolling weight and less tire friction, should bump up the mpg to near 65 maybe?? Ever thought of the Suzuki Alto 660cc engine, used in Japan? Still researching the swap…
    Hope to hear from you soon! Andrew

  28. Rick – Can you give me the name of the company where you got your full moon wheel covers. I can’t seem to find any 12″ caps like those anywhere. Thanks for all the great ideas. I’ve been slowly incorporating them into my ’91 Geo Metro, and I’ve been getting better gas mileage week by week. Averaging above 50mpg in a standard Metro. Hope to be above 60 in next 3 months.

    One more question. Can you install the higher XFI fifth gear in a standard Metro five speed, or do you have to swap out the whole transmission?

    Thanks, David Parham

  29. As for the moon alum. wheel discs. I found some 14″ Ansens, on Ebay for $35 for 4. Which fit 13″ wheels, but with a set of dividers and some pin router time on a high speed motor. The extra 1/2″ could be removed pretty quickly. These were still available last week. If U they’re gone off Ebay, I will sell U 2 of mine. Just let Me know. He had 20 more sets, last wed. Happy Metro Miles!! Andrew

  30. Rick, did the XFI have an option for A/C? If not can I add A/C as if it were a base model Metro?

  31. no a/c for them but you could dig all the parts for a/c from a junkyard and add it to the car without a lot of trouble.

  32. The transmission can be swapped or just the final drive gears can be swapped. Either way works since all the Metro/Swift transmissions are basically the same. Look on teamswift for a lot more information on the swap.

    And the 12″ moon hubcaps I had on my car were home made so other than what other people have said I have no idea where to get them. I made mine cheap but they didn’t look as good close up as they did from a bit of distance :)

  33. Thanx Rick, am I to assume that the engine compartment is virtually the same? Only ignition and valve cam pretty much distinguish the xfi?

  34. This is more of a maintenance related question. Have you had any luck keeping a new serp belt from melting down? The three rib belt on my ’91 LSI kept going away using either Gates or Dayco belts. I have a Bando belt on it now, that came with the used Jap engine I put in. That seems to hold up well, but it is old and I have’t been able to find a source for bando belts.
    Also do you have any info on the Japanese engine I bought. It’s a G-10 carbureted version ( fuel injected now, of course) currently averiging 52 mph driving on hilly winding roads. the only mod i’ve done is set the initial timing to 12 btdc from 5.

  35. Moving the cam gear a tooth is 18 degrees. It is way to much and you would be lucky to get it to run good enough to actually move under it’s own power. Half a tooth is what is ideal. anywhere from 5-10 degrees advanced is perfect for the stock cam.

  36. I have two real xfi’s i have been play with with for a while i just made a timing change from 4 to 10 btdc got 44mpg avg on 8.2 gal. 360 mi. See if it gets better. i had 23 inches of vac.

  37. i have a bone stock 96 metro that i drive as a work car. it gets a hundred miles a day on average. it is a three cylinder 5 speed, again bone stock. 36 mpg is about it. can you e-mail me a list of all engine and trans mods that can be done to up the mpg.i have another engine and trans,so it would be a blank canvas for me. if i am lucky, i will get up to 50mpg. thanx a mill, jason

  38. I have a 1997 Geo Metro 3 cyl 5 speed. Can I put an XFI cam in this car? If I swap in the XFI cam, will the car have less power…I hear that the XFI metros are not much for highway driving…I need the car to have enough power to get around safely on the freeway.

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