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Hi,

What sort of cheap mods can I do to my non fuel injection (ie carb) engine? At the moment it has K&N and advanced timing, both made a difference, though not "huge". I'm looking for around 100-120BHP. I believe turbos really need a fuel injection engine. It's 12valve.
All the mods I see are for the fuel injection engines, seems I may need a new engine?

Why don't you just change from carbed to fuel injection? their the same motor... Other non fuel things are lightening your fly wheel I'm not sure if there underdrive pulleys for this car you might even want to use high performance transmisssion oil all of that can pick up a few HP each...

Yeah, you should be able to switch it over to fuel injection for about $75-100 in parts. I think that's worth 12hp or so.

I didn't realise fuel injection gets that much more power, currently I think my engine is 87bhp. The fuel injection 4g15 only has 89bhp or something.
Where can I get extras for the engine, I know of RPW, thats about it! I do think about finding a Hyundai scoupe engine (turbo) to work with. Is it worth doing all the RPW stuff to the 4g15 or is it better to plant a 4g63 in ?

I have been told that the turbo scoupe motor won't fit its 180 degrees to what ours is... and the 4g15 w/ fuel injection is 92 HP as for deciding to mod the 4g15 or go with a 4g63t it all depends on how much power you want to make. If you want to make 130 hp or so just mod the 4g15 if to mant to make over 160hp I would then go for a 4g93 or 4g63. As for mods RPW is the best just use them....

I don't own a Mirage, so which end has the timing belts on from looking at the front of the car? On my car (based on old Mitsubishi design) it's on the right hand side. I did have a look at the RPW site and 130-160 sounds fine, more than that and I'd have to start changing lots of other parts on the car.

Proton:

Now from what I have been told the Scoupe Turbo has its timing belt on the left side of the motor. For about 120-130 HP here is what I would do

Convert to fuel injection
Lighten the Flywheel
Upgrade to a bigger TB
Get the Stage 1 RPW Cam
Get the RPW Valve Springs
Get a 2.25 Exhaust
Get a Street Style RPW header

Optional:

Port and Polish head
Shave the head for added compression.

That probably good for 125 HP and still much cheaper than getting a 4g63t in.

The problem with the 4g15 carby isn't so much the carbueration but the carbuerator. It is cheaper and easier to ditch the stock Mikuni Solex 30-32, and replace it with a better carb than it is to dismiss carbs altogether. Consider this, to replace a carb system with a TBI (which is by no means a instantly superior set up) you need to replace your mechanical fuel pump with an electrical one, than add a fuel regulator, replace the primitive ecu (and this is only if you have the Feed back carb, other wise you have to install one, and all the sensors), put in the new ecu, run whatever other sensors have to be run, run a different throttle body cable, and there is more to it. Holley makes some carbs that are much less restrictive, the 4412s is a stock replacement, but there is also the 5200, which is really an imitation weber, and of course, there is the down draft weber. Installing any of these would be much cheaper and easier, requiring re running the throttle cable. There would be power gains there that are definate. if you need more up grade your mechanical puel pump, or back it up with an electric 3-8 psi pump.
Also definitely go with a bigger exhaust and get rid of at least one of the catalytics, or replace them both with one two inch. exhaust back pressure is probably most of this engines problem any way.
But I would not be so quick to ditch to carb. besides on race day, having some thing "wierd" could definately work to your advantage. Good luck!

the exhaust is really a set back. I had the stock 1 1/2" pipes and I upgraded to a complete 2" inch straight pipe and cat back exhaust system.......a huge improvement. get rid of all the "s" curves in the stock pipes.

Yup thats probably my next upgrade is exhaust..

Conversion to EFI is not easy!!! The electrics in the carby version are very very different. There is alot of wiring to get the spaghetti stock EFI wiring harness to patch into the standard harness. You must also swap to an EFI fuel tank and install high pressure fuel lines. The instrument cluster will need to replaced as well since you need the speed sensor connection for the ECU to make it run properly. One huge PITA.

To my mind your best bet is go for a 4G93 engine swap, at least that would make converting to EFI worthwhile. Use a cheap programmable ECU like the Microtech and you can avoid some of the wiring headaches.

Looking into a carb to EFI conversion I see these problems.

Fuel pump needs to be fitted, I think an external one mounted near the engine is easier than getting a new fuel tank with pump inside.

Speed sensor would have to be taken from the dash, bit of a PITA but there you go.

I was actually looking forward to wiring it, make a custom loom as electronics is not a problem.

I don't know if I need a new head though, my current one has a hole for the carb fuel pump. Cam shaft has an extra lobe too. Would this hole be blocked off if the injection manifold is installed?

Thanks[/quote]

Yes you would need an EFI cylinder head which has larger inlet ports and cut-outs for the injector nozzles. The EFI manifold stud pattern matches the carby head but unfortunately the inlet ports themselve do not.

Hi,

Are exhaust ports the same layout as I was thinking about getting the extractors from RPW. I looked at their two designs, street and race (IIRC) and they appear to have different layouts. Does anyone know what welding has to be done to the street version?

Thanks

Puma:

Yes it does need to be done on the sreet style headers and it is a longer manifold than a stock unit...