I'm just looking for some help on this matter before I start the project. I want to take a 4G93t block and turbo and put my 4G92 Mivec head on, I've done a bit of research and know that:
1. Both Timing Belts and Tensioners are the same.
2. All the fan belts on both engines are the same with the exception of the Air Con belt but who wants Air Con anyway.
3. The clutches and flywheels are the same.
4. and the Head Gaskets are the same.

But I've been warned by a Mitsi wreckersof a few Problems
1. The 4G93 block may be taller than the 4G92 block and the Mivec head is taller than the 4G93 head so when they are bolted together you can't find a timing belt to fit. I'm not sure if this is correct but I know someone has put the non-turbo block under the 4G92 Mivec head, but I'm unsure of if it was easy.
2. The valves may knock on the pistons when the Mivec engages.

If anyone out there can answer these problems with more reliable infomation than the wrecker that would be much appreciated.

Also if anyone knows how much boost I can run on Standard 4G93t internals or if there would be any other problems, that would also be much appreciated.

Cheers

 

I applaud you for trying to attempt such a task. I have done a bit of research into the issue and I have come up with much the same conclusions with the timing belt. Although there is currently a Lancer in NZ which has done this conversion, and was successful (he would not tell me any info on his set up). However it would be easier to bore the 4G92 out to 1.8L (it can almost get there) than bolting the 4G92 head onto the 4G93 block. Just a bit of food for thought. I am quite interested to see how you go with this exercise.

 

The other option, as I'm not to worried about the extra 200cc, is to get decompressed pistons for the 4G92 and then chuck the turbo on that, but I don't know where to start looking for them.
If anyone know of a supplier for them let me know.
Cost of this project is a major issue as I could of got the 4G93t for NZ$650 but I'll be doing all the work so there's no labour involved.

 

Hi guys,

For some information on the 4G92/93 hybrid engine, go to this address:

http://www.rpw.com.au/Performance%20...r104engine.htm

These guys seem to know what they are talking about. I have considered the option myself, but it would be far too expensive for me at the moment. I am thinking about the 6A12 MIVEC engine. It would certainly give me some fun at the track I am sure.

 

Bored to 1.95L and comp ratio to a sky high 12.5.... hate to be around when something goes wrong.... its all most getting to a diesel ratio...

 

guys, i need help. i have a mirage coupe 97 and it has a 4g92 sohc engine and i'm planning to change its head to a 2nd gen MIVEC.

does the head of a mivec would fit?
what could be the problems i might encounter? (e.g. timing belts)

thanks guys!

 

Hi GSR97,
you'd have no trouble fitting the Mivec head on the block is the same and all the pulleys are at the same hieght. The problem may arise with the pistons I'm not sure but the Mivec Pistons may be different to allow for the increase in valve travel.
Also the wiring would be a problem you'd need to get the full computer etc. from the Mivec engine.
Let me know how you get on.

 

So I've spoken to RPW bout the 4G93 block and yes it is taller so i may just put a decompression Head gasket on and turbo the 92, cheers anyway. All I have to decide is How much i want to spend cos min it'll be $6000 but I can spend the extra $1400 and get forged pistons which then lets me crank up the boost above 12psi.

 

MivecCyborg,

What is the performance of the 4G92 MIVEC like. I have a Lancer 1.8 and am thinking of either putting in a 4G92 MIVEC or 6A12 MIVEC (from an FTO). Naturally, the 6A12 is not as easy (and cheap) to put in, and it is also a heavier engine.

You don't know where I could find a power-torque curve for the 4A92 MIVEC? It would be good to compare the performance of my current engine and the MIVECs.

Cheers.

 

When you bore it, you're not going to use th G92 MIVEC pistons. It'll be the G94 pistons. therefore, you're decreasing the CR.


Correct. You just need the wire harness and ecu and plug it up to the MIVEC selenoid.

MIVEC pistons are domed while the regular G9x pistons are nearly flat.

 

Ummmm it says on the site thats what the comp ratio goes to.

 

If you getting rid of your 4G93 I'd be more than happy to take it off your hands..... you in bisbane by any chance??

 

Leppy,

I think it would be a while before I change my engine. I am tossing up whether to change my engine, or buy a GSR and work on it.

I will keep you in mind if I do go ahead and change my engine. I am in Brisvegas, so I would certainly make things easy.

 

Here are some theories of mixing and matching. People in Malyasia has been doing such projects (unconfirmed outside of their country) since the CC model.

Bore and stroke (mm)
G92 = 81.0 x 77.5 w/ insane high rpm. It's well within the laws of phyics of short stroke spinning high rpm.

G93 = 81.0 x 89.0 with redline at 6500 rpm. Fuel cut at 6750 rpm. Laws of phyics applies too. Higher stroke = lesser rpm. You don't see V8's spinning 7200 rpm.

If you just bore a G92 block to .5mm, you won't get a displacement of 1.9x liter. You'll be getting like 1616 cc. Also, it's very foolhardy to use MIVEC pistons for TC app, because high CR, thin conrods, and high revving = a disaster. Besides, after bore-ing a block, you need slightly bigger pistons and rings. Too much hassle and tuning.

The effcient way. A G93 MIVEC will definately lose its sky high rpm, definately need a MIVEC controller (don't want a higher stroke motor spinning crazy rpm). A bigger bore + stroke will grant you 1856cc.

TC it using a G94 piston to match the bigger bore. Therefore, the CR will drop instantly to a more managable level. Using domed pistons for TC is too much effort to tune, unless having someone else sponsoring your budget.


Edit: my math was wrong. Made corrects

http://www.torinocobra.com/Randys_tools.htm

http://www.benedict.esu7.org/sblock/infrm.html

displacemment (cc) = pie (3.14) * Bore/2^2 * stroke * # of cyls

^ = square


Also, you can mix match on the possibility of crank + conrods, but I don't know the math formula.

 

Just realised I can't get it from ya mate.... yours being a 1993 engine and my car being a 1996.... ahh well..