CRXFi Build Thread (Geo Metro XFi drivetrain in Honda CRX)

[Christ]

Originally Posted by MetroMPG

This is too cool! You'll have it ready for GGP, right?



I'm pretty sure I've seen a thread at teamswift about how to mod a tach from a 4-cyl suzukiclone to make it work with the 3-cyl.

I've seen something somewhere, so I agree that it can be done, but does the Suzuki 4 cyl use the same kind of electronics (and signal) as the CRX does?

[MetroMPG]

Don't know the answer to that one, Topher.

[Christ]

What is the tach drive signal for the Suzuki cluster? I'd imagine it's a single wire, usually the ground from the coil. If that's the case, it should work just fine w/ the G10, with similar modding as the 4 cyl Suzuki cluster requires.

Just sayin'.

[Gasoline Fumes]

Luckily most Japanese cars use Nippon Denso or Nippon Seiki gauge clusters. They are for the most part, electronically interchangeable between Japanese cars. Convert the CRX tachometer to work with a 3-cyl engine and the Honda cluster should work fine with the Suzuki engine. The gauge side of the speedometer cables should be the same, so use the Suzuki cable if it's long enough. I'm not sure if the transmission ends are the same or not. Both Honda and Suzuki speedometers should be 1026 revolutions per mile. The Suzuki (Denso) ECU will expect to see a VSS signal from the speedometer, but I thought all PGM-FI Hondas had the VSS. I know disconnecting the cable on a 1991 Civic Wagon results in a check engine light. But if the cluster really doesn't have the VSS, you should be able to take the cluster apart and add one.

[Wonderboy]

This is too cool! You'll have it ready for GGP, right?

That's what I was planning on, but we're getting into crunch time here. I'm still waiting for the shop to finish repairing my core support and putting a new windshield in. It's going to be cheap, but it's also a low priority for the shop because they know it's my project, not a necessity. It should be done next week. The New York State Title is on its way, and I shouldn't have a problem with registering it in time, but I've got to get it roadworthy before I do that! Therein lies the challenge - I don't really know what I'm doing. I just have a mechanical inclination and a good memory for how parts go back together. I might be able to drum up some help from McTimson, but I doubt he knows any more than I do about this speed sensor and tach stuff. This will be an interesting few weeks! I feel like Ben trying to get the IRX done before he had to go back to school. Hopefully since this is a g10 it will be a bit easier. Fortunately I don't think I could've picked an easier swap with more information about the donor and the host - there is all sorts of free technical information out there on both the G10 and the CRX wiring. The question is: CAN HE DO IT IN TIME?!

BTW this might be the thread you were talking about om teamswift. I'll take a closer look at it later, but I linked it here for future reference.

[Christ]

Originally Posted by Wonderboy

That's what I was planning on, but we're getting into crunch time here. I'm still waiting for the shop to finish repairing my core support and putting a new windshield in. It's going to be cheap, but it's also a low priority for the shop because they know it's my project, not a necessity. It should be done next week. The New York State Title is on its way, and I shouldn't have a problem with registering it in time, but I've got to get it roadworthy before I do that! Therein lies the challenge - I don't really know what I'm doing. I just have a mechanical inclination and a good memory for how parts go back together. I might be able to drum up some help from McTimson, but I doubt he knows any more than I do about this speed sensor and tach stuff. This will be an interesting few weeks! I feel like Ben trying to get the IRX done before he had to go back to school. Hopefully since this is a g10 it will be a bit easier. Fortunately I don't think I could've picked an easier swap with more information about the donor and the host - there is all sorts of free technical information out there on both the G10 and the CRX wiring. The question is: CAN HE DO IT IN TIME?!

BTW this might be the thread you were talking about om teamswift. I'll take a closer look at it later, but I linked it here for future reference.

Hey, did I ever send you the Manuals for the Civic/CRX?

I've got them in email, you just gotta shoot me a message on gmail and I can fwd them to you.

Darkness.suspended@gmail.com

[Wonderboy]

I picked the car up yesterday from the body shop, and now it looks like nothing ever happened to that radiator core support. I had them fix up the sloppily bondo'd rear wheel wells too, so that looks brand spankin' new too. One of my computer repair clients called me up this last weekend and asked me to come over, so I went there with the crx shell in tow since they live near the body shop. Why did I tell you this? This client is a guy that builds race cars and has a big garage chock full of tools and a full hydraulic car lift... The guy saw my car on the trailer, asked what was up; one thing lead to another, and now he's going to help me make the custom mounts and get this thing on the road! Very serendipitous that he needed computer help right when I was picking the car up - no charge for the computer work this time!

Work date set to this upcoming Sunday! I sure am going to be hustling to get it done - eat your heart out Ben!

Edit: Question: If I use the Honda exhaust bits from the manifold back, where should the O2 sensor go? Does the XFi even have an o2 sensor (I don't remember right now). Is the honda cat (set pretty well back from the manifold) okay to use?

[Christ]

Re: The exhaust.

If the XFi doesn't have one, nothing to worry about (except if you need to go through visual emissions, but that's a different story altogether).

If the XFi does have one, best to use it's OE location (close as possible). The Civic's stock location is in one of three places: In one pipe of the exhaust manifold (not common); in the plenum of the exhaust manifold (HF/Std models); or at the union of all 4 pipes in the long-runner manifold, right above the down-pipe flange.

The Honda's catalytic converter should be OK for the 3 cylinder engine, so long as it has the same inputs (AIR, etc..).

[Wonderboy]

Thanks Chris,

The cat I have is from a CRX, and it actually looks like a stock one (long slender style vs. universal looking short and fat). A curved downpipe would extend from the manifold, head down and curve rearward, then termiante at a flange. That flange is where my cat would be if I were not to move it, but I don't think I've got much choice in the matter since I'm sure as hell not going to go buy a new cat if I don't need one. This is why I ask where I should place the o2 sensor (if there is indeed one at all): High up near the manifold, or back just before the cat.

The Honda's catalytic converter should be OK for the 3 cylinder engine, so long as it has the same inputs (AIR, etc..).

What do you mean by this?

[Christ]

Originally Posted by Wonderboy

Thanks Chris,

The cat I have is from a CRX, and it actually looks like a stock one (long slender style vs. universal looking short and fat). A curved downpipe would extend from the manifold, head down and curve rearward, then termiante at a flange. That flange is where my cat would be if I were not to move it, but I don't think I've got much choice in the matter since I'm sure as hell not going to go buy a new cat if I don't need one. This is why I ask where I should place the o2 sensor (if there is indeed one at all): High up near the manifold, or back just before the cat.



What do you mean by this?

Some catalytic converters have an AIR injection pump input on them. If the XFi has an air pump, you'd have to drill the exhaust down pipe and weld a tube for that air hose to pump fresh air into the exhaust (helps the catalytic reaction).

The O2 sensor should be close to the engine at the termination of all the cylinders, for best accuracy. Right at the top flange of the downpipe would be best. Even if you don't have one, it might be worth it to invest in a wideband if you ever plan on tweaking the engine's fuel input or trying to go lean-burn.

There are 2 stock CRX cats. The one you have is the one that can easily be replaced with a "test" pipe, that installs aft of the downpipe, near the rear forward cross member/steering rack. The other installs as part of the exhaust manifold, directly in front of the engine. The one you have will make it easier to keep the OE location of the cat (emissions law) when it comes time to make adjustments to the exhaust system for the new engine.

The CRX's stock exhaust is probably a bit large for the XFi engine, FYI. Likely won't make a notable difference, but it's just "one of those things".