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Getting Bang for the Buck From the Mitsubishi/Chrysler 3.0 V-6

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Getting Bang for the Buck From the Mitsubishi/Chrysler 3.0 V-6

Mitsubishi /Chrysler 3.0 V-6 engine upgrades and performance tips

See the Turbo-Charging the Mitsubishi 3.0 V-6 Page!

See the main 3.0 V-6 page!

Roger Lister's performance information

[For credits and a great deal of 3.0 liter information, click here].

-52mm throttle body. Look for those from the 87/88 3.0 vans, 3.3 and 3.8 vans. Also, the later model 3.8s seem to have 58mm throttle body, but this requires porting of the intake manifold where the throttle body mounts.

-89 and newer intake manifolds and plenums seem to flow more air. Especially with a mild to wild porting by Nitetrain!!!

-Nitetrain also offers PHENOLIC spacers to replace the gaskets between the intake manifold and the plenum.

-Pre-SMPI fuel rails seem to be able to flow more fuel than the later model fuel rails. (Thanks Nick)

-The fuel pumps we use are the same fuel pumps used by the Chrysler turbo cars. Unless you are making OVER 300 horses, your fuel pump SHOULD handle it just fine. Make sure you change your fuel filter regularly...

-While on the topic of fuel, I'll raise the debate on fuel injectors. Our stock injectors are 19 pound per hour (lb/hr) units. These will only support 185-190 HP. I'm planning a switch to 27 lb/hr units from the 2.2 liter turbo 1 cars. Depending on which method you use for determining how much HP these will support, they will support 235-250. The debate isn't whether they will work or not, but whether there will excessive fuel consumption during start up and warmup phases when the computer is in OPEN LOOP mode. I'm going to find this out soon enough.

-Porting and polishing the heads. This is something I'm doing now. I have a spare set I'm working on. Others (Rick Lozier and Ron Adair) have done this with GREAT success. I'm just doing a little port matching and cleanup. Nothing radical.

-Camshafts. There isn't an aftermarket cam available to us other than the ones from RPW in Australia. Crower cams in Chula Vista, CA will regrind our stock cams to any spec within reason. Be careful of increased lift though, since we would hate to turn our non-interference motors into interference... Also, SOHC 3.0 Montero cams have better duration and would appear to have better torque.

-Speaking of torque... I'd like to find out more about the SOHC 3.0 Montero intake manifold and plenum It looks sort of like the last 5.0 Mustang plenum, but I'd almost bet that the Montero setup makes more torque than our stock units... Waiting to see...

-Exhaust. Well, not much available in the aftermarket for our motors. If someone made a header set for this motor, it could be used in ALL Chrysler 3.0 platforms. No changes needed... I was thinking the earlier SOHC Mitsu Diamante manifolds were going to be the ticket, but perhaps not. Clearance issues. Same too, with the Montero manifolds. Rick Lozier had a custom set of headers made. Nitetrain is currently working on some too. Developing...

-Nitrous. Well, I'm not a fan of Nitrous for many reasons. Check this site out. KABOOM!!! Also, when the bottle is empty, your slow again. On the other hand, Rick Lozier had a good deal of success with it, dropping his Daytona 3.0 into the twelves on the squeeze... Just not for me.

-Supercharger. Seems to be a couple companies out there that have or will develop a kit for us. Sorry, when the price gets over $1000, I stop listening. But don't let that deter you if that is the way you choose. Also, Nitetrain is working on a blower for his 3.0 Daytona. The plan is to get it under the STOCK hood. Of course, check out the worlds first supercharged 3.0 liter NEON!!!

-Turbocharging. Robert Hassler has a FACTORY turbo motor. He bought two of the engineering prototypes and installed one in his car. Not all of us can drop that kind of change, but glad he could rescue these motors. But this doesn't mean we are through with this discussion... No, not by a long shot... The biggest problem, is getting an exhaust manifold or header available to ease the process. I can't weld cast iron, or i'd have been done long ago. Everyone seems to be concerned with routing exhaust back to the stock location, and I am beginning to think this is a Nirvana that won't be reached... So, I'm about to abandon ALL of my previous planning and fitment for something new... Stay tuned...

Hart Performance

Hart Performance reported on their changes to a stock 3.0 Duster. They saw no speed improvement in getting the K and N replacement air filter. An Accel 8.8 mm spiralwound spark plug kit cut about .2 seconds from the quarter mile. So did switching to an open element K&N air filter. A Forward Motion underdrive pulley reportedly helped others to drop .3 seconds. They also re-routed incoming air and, to prevent the computer from overheating, pointing a small fan at the computer and connecting it to the ignition so it is always on when the engine is running.


Dana Bontjes wrote: "Dynomax sell exhaust kits for the 2.2s, and 2.5s, but doesn't list
anything for the 3.0s. But the kit works on the 3.0s." Dana has a 1992 Daytona.

Gez's Bang for the Buck 3.0 liter V6 upgrade performance tips

gez wrote: I worked at a dealership as a tech part time during school. I have about 8 years experience working with mopar motors. Drag racing is a hobby of mine, believe it or not I started racing with Mustangs. I got dragged into 3.0 mods after I bought one for an everyday car. When I wanted to add a little kick to the 3.0 I found out that performance goodies for a 3.0 were hard to come by. So me and and a friend slammed our heads together and voila. By the way the other guy's name is Tony Garcia. If you want to put his name on the webpage feel free.

To get the most bang for under $50:

1. Make a "Ram Air".

  • Since there is no kit for the 3.0 you must make one. Here's how, (for a P-body anyway) go to A Home Depot type place and pick up a 10 ft long 3 in diameter metal dryer outlet hose, and a 3 in X 6 in rectangular heating inlet/outlet, also pick up an elbow I needed one that converted the 4 in outlet on the rectangular duct (the scoop) to the 3 in hose needed to connect to the stock air box.
  • Assembly and Installation: Locate the dust deflector under the radiator...remove it and cut 6 in off the end of the drivers side....that's where the scoop will go. Put the scoop, elbow, and hose together. Even though the pieces should fit together like Legos I used small sheet metal screws to hold the assembly together. Next put it in from the bottom of the car lining up the the right corner of the scoop with the last bolt hole from the dust deflector ( on the drivers side) ...and put a bolt through it. Next put a self tapping screw to hold the other corner. (or you can be fancy and drill an hole) Finally thread the hose in diagonally in front of the battery over the exhaust manifold, and radiator hose to the bottom of the air box.
  • Notes:
  • If you live in an area that gets snow you'll want to put the stock hose back on in the winter months or you'll have a whole new way to shovel your driveway.
  • You'll also notice that the stock hose is attached to a plastic duct in the driver's side fender, housed in that duct it the brain..why? you ask. Simple, the computer has no heat sinks to keep it cool while working so the air intake acts as a cooling fan...I have seen 3.0s in the past go for months on end with this hose disconnected with no damage to the brain whatsoever but what I did is mount a 2 in diameter electric fan on the front of the "computer duct" and hardwired it to work only when the key is on. The inlet is directly behind the drivers side headlamp.
  • If you wish to get rid of the stock air box you can buy a K&N cone air filter and stick it directly on the throttle body and put the ram air hose directly over it....this is much more noisy and I personally have not seen any advantage to this hp wise, but I've seen it done.
  • Lastly, the ram air kit cost me $17 and the fan $18 and the entire project took me just under 1 hour to complete...I know it sounds longer than that.

2. Buy a K&N panel air filter for the stock air box, available at any performance goodie store believe it or not. Cost about $40.

3. Buy a set of Nippondenso V-power spark plugs. Cost about $20. Use the stock gap.

4. Buy a set of Magnacore wires...I myself have not done this but I'm told it makes a difference. Cost around $50 I think.

5. Set the timing at 14 or 15 degrees depending on what kind of gas you want to buy. Stock is 12 degrees. To do this you must disconnect the cooling sensor first, this disables the brain and allows you to manually set the timing.

Other tips (from the same source): 60mm throttle body [webmaster note: or have yours ground and polished] High octane fuel, of course The most important thing is as always practice launching the car. I found that riding the clutch to get the car rolling and letting it out at 3-4 grand gave me the best short times. Since that run I have ported the heads, intake and exhaust manifolds and obtained a set of stickier tires. I have been told that going to a 2.5 in. exhaust from the cat back with a 2 chamber muffler also greatly increases power on the 3.0, however I have opted to leave the factory setup in place because I don't want all the extra noise.

The biggest problem in working with the 3.0 is trying to work around the factory computer, which retards the timing after 15 sec of full throttle with the automatic and immediately with the stick. I have spent countless hours researching and testing on the 3.0 and I am more than happy to share with anyone.

Benjamin Hook: 3.0 liter plenum smoothing

Most of us with a Dremel and way too much time on our hands has probably already done this. For those that haven't, here's the deal.

Remove the plenum chamber (the top half of the intake) and flip it over. You'll see about 6 screws. Take these out and you can open up the plenum. Sometimes they're stuck good, just pry it apart with a screwdriver.

Inside you'll see a bunch of ridges and a plate down the middle with more ridges. Take your Dremel and buzz down all the ridges. Don't mess with the ones on the vertical plate- they help direct air into the runners. Remember, smoother is better, so try to do a neat job. Screw the thing back together and open up the ports for the runners. If you've got the 52mm throttle body, open up the inlet to match the bigger throttle body. [Note that this might hurt idle and emissions during warm-up as these ridges are intended to increase turbulence]

How it works: Smoothing the airflow helps increase horsepower by reducing turbulence in the intake tract. In other words, the air moves easier into the cylinders instead of swirling around inside the manifold. Second, the increased intake volume will improve top-end power, moving the horsepower and torque peaks up in the RPMs. Face it, this motor is all bottom end and could do with some more top end. Remember, it was intended for minivans.

Since you moved the power peak up, you'll need to shift at a higher RPM to make the most of this.

Why it works: Beats me, I flunked Fluid Mechanics in college. I just know that I've tried it and it works.

Brad Davison's additions

RPW makes headers for this engine.

I was also thinking of using an electric water pump for a horsepower gain (less devices that the engine has to operate) - supposed to be up to a 20 hp gain.

Don't forget to mention shaving the heads and boring the block and a complete performance rebuild.

There's the TPS modification - take it off the throttle body; using a drill bit that is the same size as the original bolt hole, drill a hole counter clockwise from the hole. Connect the original hole and new hole. Repeat for the second hole. Put the sensor back on the throttle body, in the original position, and reconnect the wiring.

Crank the motor and let it idle. Now loosen the bolts and turn the top of the sensor towards the front of the engine bay. When the idle goes crappy back the tps up a bit and tighten the bolts down. Close the hood and enjoy your new found power.

The Mitsubishi Montero tranny should work for a rear wheel drive conversion? Take it a step further, I read that a 24v 3.0 would bolt to the A604 tranny, I would hope it could bolt to the mitsu tranny also so I could just ditch the stock. The twin turbo engine uses a 6 speed Getrag tranny so I could never go to that and get rwd (I am thinking about a mid engine rwd conversion and building the engine from toe up ditching the a/c for a supercharger and ditching water pump for electric).

The beginning for my own car. Parts/price list:

  • Supercharger(from a early/mid 90s Ford Super Coupe) $200
  • Vortech Super Fuel Management Unit $200
  • Chrysler Turbo II injectors of the 33# variety $ 80 for 8 injectors
  • Blow Off Valve from 1st Gen DSM $ 35
  • Injector o-rings (only in packs of 8 rings) $ 10 for 2 sets
  • RTV gasketmaker $ 10 for 2 tubes
  • Various vacuum lines $ 15
  • BOV extention hose $ 7
  • 2.5in exaust piping for intake plumbing $ 15 for 3ft
  • 2.5-3inch exaust adaptor $ 5
  • Steel sheet (16 gauge) $ 8
  • Pieces of 1/4in steel L-beam and stock $ 30 Various welding(pipes to sheet for super in/outlets) $ 30
  • 90° Rubber elbows(from hardware store for now:) $ 15 for 3 of them
  • Exaust Temp Gauge $ 85
  • Air/Fuel ratio gauge $ 50
  • Boost gauge(0-30PSI) $ 40
  • Fuel Pressure gauge and fitting(under hood) $ 40
  • Various bolts, screws, nuts, washers(all grade 8) $ 50
  • K&N cone filter(2.5in inlet) $ 40

Total: $875 if my math is correct. A far cry from the $3000-$4000 that one will pay for a kit. No kits are offered for my car or this motor type to the best of my knowledge and there is a very limited aftermarket.

The supercharger bracket is made of mostly L beam pieces bolted together, with pieces of 1/4in stock used to strengthen and connect various points. All pieces are held together with nuts, bolts and washers (no welding access at this point in the project). BOV Pipe was made with a piece of 2.5in stainless exaust pipe a piece of 1in pipe and a piece of 1/4 inch steel stock. Took the exaust pipe, punched a hole in it close to an inch in diameter in it and welded the 1in section of pipe to it. Took the 1/4in stock and cut it down to match the BOV mounting point and put a hole a bit less than 1inch in the center of it. Welded the plate to the small pipe and sprayed it all black. The Supercharger inlet was made from a 6inch piece of 2.5in exaust pipe that was modified so one end was oval(roughly the same size as the actual inlet on the blower) and the other side was still round. Took a piece of the sheet steel and cut an oval hole in it to match the inlet and the pipe, then drilled holes for the bolts. Welded the oval parts of both pieces together. The Supercharger outlet makes use of the 3inch to 2.5inch exaust reducer and another section of the sheet steel. I made a hole in the sheet steel 3inches wide and welded the large end of the pipe to the sheet, then drilled various holes for connectors. Some of the holes in this plate are lined up with the bracket and blower attachment points for added strength

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