vr6
08-28-2002, 08:09 AM
maybe you guys know about this already.
nice info. https://www.thegalantcenter.org/style_emoticons/default/smile.gif
hmmmm.... maybe outdated for the aftermarket support part.
Mitsubishi 6G72 SOHC V6 gasoline fueled motor.
This motor was used in many different cars in the US. In 1987, Chrysler needed a V6 motor for their minivans. Chrysler had one under developement, but it wasn’t available until 1989. Chrysler owned a substantial amount of Mitsubishi Motors, and Mitsubishi had a good 3.0 liter Single OverHead Cam V6 available. This motor was used in the minivans right up until the 2000 model year. But the motor was a strong selling feature not just in the minivans, but just like the 2.2/2.5 liter turbocharged motors, the 3.0 was available in pretty much everything except the L bodies (Omni, Charger, Horizon...), this included the AA bodies (Spirit, Acclaim, LeBaron Sedan and in Europe, the Chrysler Saratoga), AC bodies (Dynasty, 5th Avenue), AG body (Daytona, Laser), AJ body (LeBaron Coupe and Convertible AND the Chrysler TC by Maserati), AP bodies (Shadow, Sundance, Duster), and of course, the AS bodies (Caravan, Voyager).
This motor was also used in the Misubishi Montero/Dodge Raider SUV, Hyundai Sonata sedan (1st generation), Mitsubishi 3000GT/Dodge Stealth, Mitsubishi Diamante sedan and some Mitsubishi trucks. Even some Mitsbishi made forklifts have a version of this motor, albeit, with a carburator and no computer controls.
Two other important versions of the 6G72 are the DOHC N/A 225 HP motor and the DOHC Twin Turbo (TT) 320+ HP motor. These motors saw duty in the Stealth/3000GT cars. The DOHC N/A motor, as well as a 3.5 liter version survive on in many Mitsubishi cars and the Montero series SUV, as well as a 3.0 liter version for the third generation Eclipse, and the 2001 Dodge Stratus and Chrysler Sebring Coupes (which again are stretched Eclipse chassis’). The four door versions of the Sebring/Stratus survive as the cloud cars, including the Sebring convertible which all three cars receive Chrysler motors, not Mitsubishi.
In the rebodied Eclipses that Chrysler used (Dodge Avenger/Chrysler Sebring Coupes) and the “Cloud” cars (Stratus, Breeze, Cirrus), the 6G73 was employed. This motor is a 24 valve, DOHC 2.5 liter version sharing the basic block, with a shorter stroke. This motor also uses a distributor, and a MAP sensor. And it generates 50 HP more than the SOHC 6G72. The 6G73 has a short coming though. The intake system is at its basic limits. Adding a “Dry” nitrous system will cause one cylinder to go leaner than the rest. This is because the intake is NOT of the best design. Bill Rhinehart and others of Avenger.Sebring Owner’s Group (ASOG) have run into this problem. They are working with Superchips to develop a performance chip to allow the computer to add fuel. This chip will be beneficial to ASOG, as well as the “Cloud” cars. Will it help us in the SOHC 6G72 world? Probably not. A shame too.
Some of the major changes made during the production run of this motor include: Roller cams, improved valve guides, improved intake plenum, and a change from 2.25” to 2.5” exhaust manifolds. and essentially, a few computer program changes. Other than that, the 6G72 remained pretty much unchanged form 1987 through 2000.
As used by Chrysler, in FWD vehicles, this motor could be interchanged between platforms with no hardware changes. The same can’t be said for the Mitsubishi versions of this motor. At least two different oil pumps, four different water pipes, three different lower intake manifoldsm three different intake plenums... Two different heads, well, you get the idea...
Why can’t the DOHC twin turbo motor be used in the Chrysler cars? Start with the oil pump places the oil filter where the Chrysler version has the power steering pump. It MIGHT fit, but... Also, the exhaust will need to be upgraded too. Oh, the computer will need to be changed, and ALL the wiring, and other sundry things. Why change the computer? Well besides the fact that the upgraded computer runs the motor more efficiently... The TT motor doesn’t have a distributor, uses Mass Air Flow technology, um, has turbos... And all of that is connected to the computer. The Chrysler version of the SOHC motor shares the distributor with the Mitsu version of the 6G72, but uses a Manifold Absolute Pressure system. The Chrysler version tries to be as fuel efficient and enviromentally friendly, but not as performance oriented as it could be. Many will back this up, but in the right lightweight body, even the SOHC version is QUITE powerful for its size and weight. This motor is capable of more power, but the computer isn’t quite willing to let that happen.
So, without duplicating info already available on the net, how is more power available still using the stock computers? Here are some of my ideas... Now, this takes into account the “usual” mods, 52mm throttle body, open element air filter, synthetic oils and lubricants... You get the idea. But here are my thoughts for “More Power”...
Normally Aspirated... Actually, some of this applies to N/A as well as forced induction, but we’ll get to that in a bit. First, why did Chrysler spec 19 pound per hour fuel injectors? To keep the motor “Green”. Rick Lozier has shown the path here, by using larger capacity injectors and using an adjustable Fuel Pressure Regulator, and basic hotrodding techniques this motor can make some serious power. 200 Horsepower is attainable. Rick made 250 HP and added a 175 HP Nitrous kit... Timing was altered, and fuel was added with the NOS... So what does that have to do with me? Well, I’m working a set of heads from a 1990 Lebaron drop top for use on my 87 Grand Caravan. The 1990 heads have the roller cams and rockers. My 1987 heads don’t. The plan is to do a port and polish job. Not an outragous amount mind you, as the van IS my daily driver. The plan is to clean the ports and straighten them as much as possible. Intake side will be gasket matched, plus a bit. Exhaust side will be worked for flow and to prevent exhaust flow reversion (the front manifold design is pretty bad...). I enjoy off the line torque, but speed is where it is... I want throttle response at 85 MPH. The port work, polishing after that, micro polishing the combustion bowl... I’m hoping for much improved throttle response at speed. More flow, more speed. As long as the larger (52 PPH) injectors provide fuel...
But what if I want MORE off the line power? Well, I’ve been an advocate for using an Eaton supercharger similar to those used in GM 3800 seies motors, and the Thunderbird Super Coupes... The blower is designed to support from 3 to 5 liter motors. Well, here is the 3.0... Now, using this blower requires all the N/A mods, and requires a very modified or totally custom intake. A member of the 3 liter crowd has picked up one of these blowers. I just can’t wait to see if I was right...
Another idea, and one I’m actively pursuing... Is the turbocharger. I am not alone here. There are three basic ideas for this project. Two work in all platforms. Mine works pretty much only in the minivans. All require modifications to the original exhaust system which, admittedly, is not the best design. The rear manifold is a decent design, except for the included crossover from the front. The crossover goes over the transaxle and connects to the end of the front “log” shaped manifold. This thing is flat and I believe was made so for packaging reasons. Well, this design just doesn’t work for making power. Rick L. had a set of headers custom built. Are they the best design? Probably not, but so much better than the original system... Two of the turbo designs have the turbo mounted where the exhaust crossover is. My design places the turbo at the end of the original rear manifold, but modified with a mounting flange for the turbo. This method places the turbo down behind the motor, keeps the heat out of the engine bay, and if the stock air filter box is modified, can even appear to be, well, stock. again this method would work best for the vans due to firewall and floorpan clearances.
Some other issues being looked into for the 6G72, using some stock Mitsubishi components for more power. I’d like to get ahold of the exhaust manifolds from a Diamante. They point straight down and a crossover or EQUAL LENGTH “Y” pipe could be fabricated. Might even help in the turbo packaging. I have seen the Montero manifolds used on a Mini-Ram Cargo Van. The owner even had a dual exhaust based off these manifolds. While this arrangement might be hard to get past the California smog tests, since he lives in Nevada, it doesn’t appear to be a problem yet. Another stock Mitsu item is the SOHC lower intake manifold. Now, there appears to be some debate over which intake plenum is better, since the plenum in the Mitsu cars and the Montero and trucks is quite different. Me, I think the best airflow and torque would come from the Montero plenum. But I have more underhood clearance too. I reckon if I had one of the other platforms, hood clearnce would be a factor. Again, who suspects a minivan...
There is currently only one manufacturer of high performance parts for this motor. Racing Performance Works of Perth, Western Australia. If only I’d been into this scene and known about RPW when I was last in Perth 3 years ago... Oh well, if I ever get to go back... Anyway, at RPW they do rebuilds, bore blocks, grind custom cams, even have developed a stroker kit which makes the 3.0 a 3.3. They also do custom porting and poishing and have developed custom intakes. How about 6 inline throttle bodies on the Mitsu lower manifold? Better yet, how about 2 pairs of three throttle bodies for the Chrysler lower intake? Nothing like a Mopar with a 6 Pack under the hood... A couple of problems with RPW stuff. They will quote you Autralian dollar prices. After the conversion though, the shock does wear off. The other is the shipping charges. Phantom Racing run by Cedric Kelly has stoood up and hung his shingle for business. He imports RPW’s parts. Rick Lozier is a customer and a couple others. Rick has maxed out what is available in the States. He blew up his second motor nearly a year ago, and has been rebuilding with RPW components. Can’t wait to see the finished product Rick...
So, this is where we are with the 6G72. A good strong motor, that CAN make more power, but is limited by money and lack of aftermarket support. Even Mopar Performance offers NOTHING for this motor. Talk about being the unwanted step children...
nice info. https://www.thegalantcenter.org/style_emoticons/default/smile.gif
hmmmm.... maybe outdated for the aftermarket support part.
Mitsubishi 6G72 SOHC V6 gasoline fueled motor.
This motor was used in many different cars in the US. In 1987, Chrysler needed a V6 motor for their minivans. Chrysler had one under developement, but it wasn’t available until 1989. Chrysler owned a substantial amount of Mitsubishi Motors, and Mitsubishi had a good 3.0 liter Single OverHead Cam V6 available. This motor was used in the minivans right up until the 2000 model year. But the motor was a strong selling feature not just in the minivans, but just like the 2.2/2.5 liter turbocharged motors, the 3.0 was available in pretty much everything except the L bodies (Omni, Charger, Horizon...), this included the AA bodies (Spirit, Acclaim, LeBaron Sedan and in Europe, the Chrysler Saratoga), AC bodies (Dynasty, 5th Avenue), AG body (Daytona, Laser), AJ body (LeBaron Coupe and Convertible AND the Chrysler TC by Maserati), AP bodies (Shadow, Sundance, Duster), and of course, the AS bodies (Caravan, Voyager).
This motor was also used in the Misubishi Montero/Dodge Raider SUV, Hyundai Sonata sedan (1st generation), Mitsubishi 3000GT/Dodge Stealth, Mitsubishi Diamante sedan and some Mitsubishi trucks. Even some Mitsbishi made forklifts have a version of this motor, albeit, with a carburator and no computer controls.
Two other important versions of the 6G72 are the DOHC N/A 225 HP motor and the DOHC Twin Turbo (TT) 320+ HP motor. These motors saw duty in the Stealth/3000GT cars. The DOHC N/A motor, as well as a 3.5 liter version survive on in many Mitsubishi cars and the Montero series SUV, as well as a 3.0 liter version for the third generation Eclipse, and the 2001 Dodge Stratus and Chrysler Sebring Coupes (which again are stretched Eclipse chassis’). The four door versions of the Sebring/Stratus survive as the cloud cars, including the Sebring convertible which all three cars receive Chrysler motors, not Mitsubishi.
In the rebodied Eclipses that Chrysler used (Dodge Avenger/Chrysler Sebring Coupes) and the “Cloud” cars (Stratus, Breeze, Cirrus), the 6G73 was employed. This motor is a 24 valve, DOHC 2.5 liter version sharing the basic block, with a shorter stroke. This motor also uses a distributor, and a MAP sensor. And it generates 50 HP more than the SOHC 6G72. The 6G73 has a short coming though. The intake system is at its basic limits. Adding a “Dry” nitrous system will cause one cylinder to go leaner than the rest. This is because the intake is NOT of the best design. Bill Rhinehart and others of Avenger.Sebring Owner’s Group (ASOG) have run into this problem. They are working with Superchips to develop a performance chip to allow the computer to add fuel. This chip will be beneficial to ASOG, as well as the “Cloud” cars. Will it help us in the SOHC 6G72 world? Probably not. A shame too.
Some of the major changes made during the production run of this motor include: Roller cams, improved valve guides, improved intake plenum, and a change from 2.25” to 2.5” exhaust manifolds. and essentially, a few computer program changes. Other than that, the 6G72 remained pretty much unchanged form 1987 through 2000.
As used by Chrysler, in FWD vehicles, this motor could be interchanged between platforms with no hardware changes. The same can’t be said for the Mitsubishi versions of this motor. At least two different oil pumps, four different water pipes, three different lower intake manifoldsm three different intake plenums... Two different heads, well, you get the idea...
Why can’t the DOHC twin turbo motor be used in the Chrysler cars? Start with the oil pump places the oil filter where the Chrysler version has the power steering pump. It MIGHT fit, but... Also, the exhaust will need to be upgraded too. Oh, the computer will need to be changed, and ALL the wiring, and other sundry things. Why change the computer? Well besides the fact that the upgraded computer runs the motor more efficiently... The TT motor doesn’t have a distributor, uses Mass Air Flow technology, um, has turbos... And all of that is connected to the computer. The Chrysler version of the SOHC motor shares the distributor with the Mitsu version of the 6G72, but uses a Manifold Absolute Pressure system. The Chrysler version tries to be as fuel efficient and enviromentally friendly, but not as performance oriented as it could be. Many will back this up, but in the right lightweight body, even the SOHC version is QUITE powerful for its size and weight. This motor is capable of more power, but the computer isn’t quite willing to let that happen.
So, without duplicating info already available on the net, how is more power available still using the stock computers? Here are some of my ideas... Now, this takes into account the “usual” mods, 52mm throttle body, open element air filter, synthetic oils and lubricants... You get the idea. But here are my thoughts for “More Power”...
Normally Aspirated... Actually, some of this applies to N/A as well as forced induction, but we’ll get to that in a bit. First, why did Chrysler spec 19 pound per hour fuel injectors? To keep the motor “Green”. Rick Lozier has shown the path here, by using larger capacity injectors and using an adjustable Fuel Pressure Regulator, and basic hotrodding techniques this motor can make some serious power. 200 Horsepower is attainable. Rick made 250 HP and added a 175 HP Nitrous kit... Timing was altered, and fuel was added with the NOS... So what does that have to do with me? Well, I’m working a set of heads from a 1990 Lebaron drop top for use on my 87 Grand Caravan. The 1990 heads have the roller cams and rockers. My 1987 heads don’t. The plan is to do a port and polish job. Not an outragous amount mind you, as the van IS my daily driver. The plan is to clean the ports and straighten them as much as possible. Intake side will be gasket matched, plus a bit. Exhaust side will be worked for flow and to prevent exhaust flow reversion (the front manifold design is pretty bad...). I enjoy off the line torque, but speed is where it is... I want throttle response at 85 MPH. The port work, polishing after that, micro polishing the combustion bowl... I’m hoping for much improved throttle response at speed. More flow, more speed. As long as the larger (52 PPH) injectors provide fuel...
But what if I want MORE off the line power? Well, I’ve been an advocate for using an Eaton supercharger similar to those used in GM 3800 seies motors, and the Thunderbird Super Coupes... The blower is designed to support from 3 to 5 liter motors. Well, here is the 3.0... Now, using this blower requires all the N/A mods, and requires a very modified or totally custom intake. A member of the 3 liter crowd has picked up one of these blowers. I just can’t wait to see if I was right...
Another idea, and one I’m actively pursuing... Is the turbocharger. I am not alone here. There are three basic ideas for this project. Two work in all platforms. Mine works pretty much only in the minivans. All require modifications to the original exhaust system which, admittedly, is not the best design. The rear manifold is a decent design, except for the included crossover from the front. The crossover goes over the transaxle and connects to the end of the front “log” shaped manifold. This thing is flat and I believe was made so for packaging reasons. Well, this design just doesn’t work for making power. Rick L. had a set of headers custom built. Are they the best design? Probably not, but so much better than the original system... Two of the turbo designs have the turbo mounted where the exhaust crossover is. My design places the turbo at the end of the original rear manifold, but modified with a mounting flange for the turbo. This method places the turbo down behind the motor, keeps the heat out of the engine bay, and if the stock air filter box is modified, can even appear to be, well, stock. again this method would work best for the vans due to firewall and floorpan clearances.
Some other issues being looked into for the 6G72, using some stock Mitsubishi components for more power. I’d like to get ahold of the exhaust manifolds from a Diamante. They point straight down and a crossover or EQUAL LENGTH “Y” pipe could be fabricated. Might even help in the turbo packaging. I have seen the Montero manifolds used on a Mini-Ram Cargo Van. The owner even had a dual exhaust based off these manifolds. While this arrangement might be hard to get past the California smog tests, since he lives in Nevada, it doesn’t appear to be a problem yet. Another stock Mitsu item is the SOHC lower intake manifold. Now, there appears to be some debate over which intake plenum is better, since the plenum in the Mitsu cars and the Montero and trucks is quite different. Me, I think the best airflow and torque would come from the Montero plenum. But I have more underhood clearance too. I reckon if I had one of the other platforms, hood clearnce would be a factor. Again, who suspects a minivan...
There is currently only one manufacturer of high performance parts for this motor. Racing Performance Works of Perth, Western Australia. If only I’d been into this scene and known about RPW when I was last in Perth 3 years ago... Oh well, if I ever get to go back... Anyway, at RPW they do rebuilds, bore blocks, grind custom cams, even have developed a stroker kit which makes the 3.0 a 3.3. They also do custom porting and poishing and have developed custom intakes. How about 6 inline throttle bodies on the Mitsu lower manifold? Better yet, how about 2 pairs of three throttle bodies for the Chrysler lower intake? Nothing like a Mopar with a 6 Pack under the hood... A couple of problems with RPW stuff. They will quote you Autralian dollar prices. After the conversion though, the shock does wear off. The other is the shipping charges. Phantom Racing run by Cedric Kelly has stoood up and hung his shingle for business. He imports RPW’s parts. Rick Lozier is a customer and a couple others. Rick has maxed out what is available in the States. He blew up his second motor nearly a year ago, and has been rebuilding with RPW components. Can’t wait to see the finished product Rick...
So, this is where we are with the 6G72. A good strong motor, that CAN make more power, but is limited by money and lack of aftermarket support. Even Mopar Performance offers NOTHING for this motor. Talk about being the unwanted step children...