DISCLAIMER!!: I've listed the modifications I have made to my own car. Modifications made improperly to your own car could result in major damage to it. This entire web site should be viewed as an education tool only. Any modifications you may make to your own car are strictly your own responsibility. With that out of the way ...Background:
I bought the car used in stock condition 4 years ago with about 55,000 miles. Incidentally, I live in Colorado Springs with an altitude of about 6000 feet, which reduces how much power an engine makes compared to sea level. Apart from the usual fixes like replacing worn out rear hatch shocks, burnt out bulbs, replacing the bald tires, etc, I did nothing to increase the engine's power. My boss also had a Mitsubishi (all wheel drive Talon) & began telling me how easy it was to gain horsepower. The car wasn't too bad just the way it was. But the engine seemed to get sluggish around 6000 rpm plus you can never have too much horse power. Or as the maker of the 427 SC Cobra, Carol Shelby once said, "Too much horsepower is just right." Even though the car, like myself, has seen better days, I ordered a "300HP" East Coast Racing kit. The kit is described below.Kit Components:
The increase in power was obvious. However, I ran into a persistent problem with fuel cut off starting as low as 5000 rpm. The fuel cut off was triggered by a too rich fuel / air mixture. I tried the various tricks to fix the problem mentioned in some web sites like removing the smaller aluminum honeycomb from the air filter assembly, adjusting a screw affecting the fuel / air ratio, etc. But the fuel cut-off problem persisted. In case you are not familiar with what the fuel cut off does, it shuts off the fuel to the engine to prevent overreving the engine & it feels like hitting the brakes when it happens. For some reason, the fuel cut off would also be activated if the fuel / air mixture was too rich.Photos of Mods:
The fuel cut off was driving me nuts so I bought an HKS VPC unit that allows for better adjustment of the fuel / air ratio. Carefully leaning out this mixture finally eliminated the fuel cut off problem. One important caution is if the fuel / air mixture is leaned out too much, then the engine will detonate which could destroy the engine. Great care must be taken anytime the fuel / air ratio is leaned out. Another thing I liked about the VPC unit was that it replaced the complete air filter assembly with a clean tube the same diameter as the the inlet hose to the turbo. It also required a temperature sensor be installed on the intake & required a sensor to monitor the boost pressure. I used a free flowing HKS "Mega Flow" air filter.
The engine, with over 99,000 miles, now revs freely and hard right up to the 7000 rpm redline without missing a beat! Does the car have 300 HP? Probably not, but it has a bunch more than when it was stock! There was an unexpected problem. My clutch, with less than 15,000 miles could not handle the extra horsepower and got fried. I had it replaced with a Clutch Masters Kevlar composite clutch disk. This clutch has over 20,000 miles and has held up with no problems.
These are thumbnails of modifications I made, just select to see larger photos of ones. Also, to minimize the web page loading time, the larger pictures are of low resolution but should still be usable.
 |
 |
 |
| HKS Air Filter . |
Bypass Valve . |
Connections For Boost Monitoring |
 |
 |
 |
| Pressure Sensor | Boost Gauge | HKS VPC |
 |
||
| VPC Temperature Probe |
 |
 |
| Gen1 & Gen2 Lifters | Air Fuel Ratio |
On July 25, 1999 I drove my car up to Bandimere Speedway to see the Import Challenge and also to drag race my car to see what it would do. Since there were around 400 cars, I was only able to get in two time trial runs. I found the car to be tricky to launch. Too high an RPM & I just got useless tire spin, too low an RPM and the engine bogged. The RPM band between engine bog and tire spin was pretty narrow. For me, using all season street tires, around 4500 RPM seemed to work best for launching. The all wheel drive Mitsubishi's had a big advantage when it came to launching off the start line. My best ET was a 15.1 at 93.43 MPH. Certainly there were much faster Mitsu's there but for my 1st try at drag racing my front wheel drive daily driven car and at an elevation of around 6000 feet, it wasn't too bad. With drag tires on the front & more runs to tweak the car & launching technique, I think my daily driver could make it consistently into the high 14's. Incidently, the photo at the top was taken at Bandimere Speedway (I was number 111, you can see the number up in the upper left of the windshield). The ET slip for this run is below.
This is somewhat wishful thinking (because of my financial situation), but the modifications I would like to make to this car and still have it be a daily driver include:Reality:1) Performance block rebuild 2) Extrude hone the head 3) Use Gen 2 lifters (Done) 4) Use Gen 2 (or custom) exhaust manifold 5) Performance 16G turbo 6) Front mount intercooler 6) Mandrel bent air pipes 7) Low restriction cat & muffler 8) 550 cc injectors 8) Mandrel bent exhaust piping 9) Bigger wheels & brakes 10) Lower car around 1" 11) Performance shocks 11) Polyurethane bushings 12) Strut tower braces 13) Upgraded sway bars 13) Clutch that could take it 14) Fuel / Air ratio meter in car (Done) 15) Toughest tranny availableThat's all ... With the above mods made & properly setup, the engine should make easily over 350 HP and handle quite well. There are daily driven Mitsu's that make considerably more power than this. Why drive a car with this much power? See Carol Shelby quote.
Being married, my paycheck will stretch only so far. Actually, the car is fun to drive the way it is. But ... the engine does have over 99,000 miles. Probably need a rebuild sometime (performance block rebuild shouldn't be that much more than a standard rebuild) ... might as well extrude hone the head (can't cost that much) ... be a good time to upgrade the turbo ..... What the hell, we can always cut back on luxuries, like food, for awhile .....Links:
This is by no means a comprehensive list. It does list some of the more extensive sites to get you started in checking out how to increase the horse power in a Mitsubishi 4-Banger significantly.
Bushur Racing this is easily one of the best sites for learning about how to upgrade your Mitsubishi turbo 4 banger on the web. Dave Bushur races Mitsubishi cars (at the very least, he has one of the fastest 4 cylinder drag cars), has extensive experience and sells performance parts and service. Some parts are only available from this site.
Extreme Motorsports this is another excellent site that offers a great selection of high performance parts and service. They have prepared some 'Extreme'ly fast cars.
Road Race Engineering, this is another source of parts & services for the turbo Mitsubishi cars.
Technomotive this site has an excellent history on the turbo Mitsubishi cars. A data recoder that can plug into a service port in the car & then to a laptop is available here that apparently is the best you can get for the Mitsubishi. This provides very detailed information on what's going on with the engine.
Mitsubishi Owners Club this is a good site for contacting other Mitsubishi owners and learning about Mitsubishi clubs in your local area. It offers loads of other information about turbo Mitsubishi's.
While this is not a link, I would highly recommend checking out Turbo & High-Tech Performance magazine. Most of the above sites and many more are listed in this magazine. It's loaded with very informative articles on high performance import turbo cars and some domestic cars. Finally, a good newsgroup to check out is alt.autos.mitsubishi.
