Also get a 160 fail safe thermostat. Your going to want to keep the engine as cool as possible to prevent any detonation

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Problem with this is the system will then run in an "open loop" condition since the temp sensor is reading the coolant temp and will tell the ECU to keep firing in more IRAQ fuel, thus keeping you in a rich mixture at all times.

Stay with the 195 * t-stat - for your motor and your wallet will really like you. Even if you get crazy with the turbo option..stay with the 195 T-stat.

If built correctly, our little 4G37's in as much as the 4G63's runs the best when hot - they way the engineers designed them at the Mitsu motor factories in Japan ... and I figure they kinda know more than us 'garage mechanics'.

So ,why mess up a good thing?

DSM1G90 said:

Problem with this is the system will then run in an "open loop" condition since the temp sensor is reading the coolant temp and will tell the ECU to keep firing in more IRAQ fuel, thus keeping you in a rich mixture at all times.

Stay with the 195 * t-stat - for your motor and your wallet will really like you. Even if you get crazy with the turbo option..stay with the 195 T-stat.

If built correctly, our little 4G37's in as much as the 4G63's runs the best when hot - they way the engineers designed them at the Mitsu motor factories in Japan ... and I figure they kinda know more than us 'garage mechanics'.

So ,why mess up a good thing?

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This motor likes to run cold. And no it will not go into open loop with a colder t-stat. Even if you completely remove the t-stat, run both fans all the time in the dead of winter it still will not go into open loop due to temp sensor readings.

The motor Will only go into open loop above 4k rpms AND above 50% throttle. Both those conditions must be meet in order for it to go into open loop. Or if you do the 2.0 tb mod and just leave your tps off to the side but still plugged in, It goes into open loop above 4k rpms.

, if you run a cold tstat it won't come out of warm up enrichment, and it will get poor mileage. Ask me how I know that.

bastarddsm said:

, if you run a cold tstat it won't come out of warm up enrichment, and it will get poor mileage. Ask me how I know that.

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How do you know? Because my wideband and all my data logs say otherwise. Not to mention i've still gotten better than 30mpg when my failsafe tstat failed and was stuck open for weeks.

wickedtalon93 said:

thanks wes, man that is a huge help i do believe this will be the new path im going to take it will come out cheaper in the long run and i will get more HP for my money

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If your going the turbo route then it is a must you do something about your timing, and that closed loop condition i've been speaking about.

Ecu timing during cruise is around 40-50 degrees of advanced, wot timing is 30 degrees. This is with your distributor set at 0 degrees advanced timing. This is a HUGE isssue if your going to turbo it. You will not be able to keep a head gasket on it and keep it from developing leaks if you dont address this issue.

Closed loop below 4k. If you run that colt mani your going to be using a small turbo that will reach full boost before 4k, while your in closed loop. Very bad. Even my 14b turbo starts spooling around 2k and is fully spooled by 3.8 in 1st-3rd. In 4th and 5th it will hit full spool at 3k.

Also the stock ecu hits a maf cap around 1000hz...and an injector duty cap of around 50%. Hell my n/a maf logs look the exact same as my turbo logs, just the turbo it hits everything way sooner. Thats another issue...getting the required fuel. A safc wont overcome these issues.

If you want it to be reliable and last you need to have all of these things addressed. IF you dont then it will only last for a little while before you blow a head gasket.

So either go with megasquirt, or maft pro. Only 2 real options....besides doing hack mods to the distrubitor and ecu.

It's a fact that the ecu doesn't remove cold enrichment until like 180*. In the winter my car ran at about 150 with a failed tsat.

bastarddsm said:

It's a fact that the ecu doesn't remove cold enrichment until like 180*. In the winter my car ran at about 150 with a failed tsat.

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Whose to say it will run that cold? My gf 2g with no tstat warmed completely up to temp. It just took longer. If your car ran that cold it was because your mix was too water based & not enough antifreeze.

Mischif said:

Closed loop below 4k. If you run that colt mani your going to be using a small turbo that will reach full boost before 4k, while your in closed loop. Very bad. Even my 14b turbo starts spooling around 2k and is fully spooled by 3.8 in 1st-3rd. In 4th and 5th it will hit full spool at 3k.

Also the stock ecu hits a maf cap around 1000hz...and an injector duty cap of around 50%. Hell my n/a maf logs look the exact same as my turbo logs, just the turbo it hits everything way sooner. Thats another issue...getting the required fuel. A safc wont overcome these issues.

If you want it to be reliable and last you need to have all of these things addressed. IF you dont then it will only last for a little while before you blow a head gasket.

So either go with megasquirt, or maft pro. Only 2 real options....besides doing hack mods to the distrubitor and ecu.

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now just wondering how much do i need to advance my timing and also going back to another question i asked, do i need to do any tranny work or can the stock 1.8 tranny hold

Retard your timing! not advance it. The amount will depend on your particluar setup. But before i hacked mine, i was almost at full retard on the distributor at 11psi of boost. Which i would guess to be around -20 degrees btdc.... You only really need to pull about 10 or so degrees of timing from tdc so that your WOT timing is good, but then your cruising timing is still too much and thats where most of the detonation will happen. Which is the reason you will need to go almost full retard on the distributor. Off boost performance sucks tho, its a slug. Thats why i wound up doing a hack to mine that wound up working decently. Also your going to want to keep the engine temp around 170, that seems to be the sweet spot. 180's are okay During wot full boost, but once it gets around 190 detonation starts occuring. And if you hit 200 then forget it even light cruising it'll start detonating.

The non turbo tranny will hold up just fine. The stock clutch will be fine for up to 11psi as well.

How do you know? Because my wideband and all my data logs say otherwise. Not to mention i've still gotten better than 30mpg when my failsafe tstat failed and was stuck open for weeks.

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FOR, he's right since he's been there and done that - and he didn't have any electronic junk to tell him that. He used common sense.

This motor likes to run cold. And no it will not go into open loop with a colder t-stat. Even if you completely remove the t-stat, run both fans all the time in the dead of winter it still will not go into open loop due to temp sensor readings.

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Open loop is when the ECU is not getting the minimum 177* reading from the temp sensor. Thus it's in open loop to run slightly rich - as B-DSM mentions .. and I've been there and done that as well with other vehicles where the T-stat has stuck open.

Now, why would I want to run BOTH fans in the dead of winter with the T-stat GONE and the thing is stuggling to get to operating temperature?

You would think that when a vehicle comes out of the factory with 195* T-stats installed, it was for a very good reason WHY that range was installed in the first place.

If your car ran that cold it was because your mix was too water based & not enough antifreeze.

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Not even. With no T-stat, water couldn't get warm enough due to it couldn't pull the heat off the block quick enough.

Water might be just nice and warm, but your block is pushing 600 degrees and ready to crack.

This is why we have T-stats: to "throttle" down the coolant flow to make the coolant flow slower to be able to pull the heat of the block more effectively.

You run without t-stats and you're pushing into the red zone to crack a block from getting massively over heated since it can't be cooled down effectively.

Learned this lesson the hard way. Has a Toyota Corolla, got smart and removed the T-stat to make it run cooler. This was during the hot summer. Guess what? A month later, my oil consumption drastically increased and motor was smoking, and when I checked the oil, it was milky gray. Took it to a shop and the block had a 3inch crack. I couldn't figure out why until they gave me the lesson on T-stat elimination that the block was reaching 700 degrees and it let go since it couldn't get the heat off due to coolant was speeding past the walls so fast that it wasn't pulling the heat off the walls.

DSM1G90 said:

FOR, he's right since he's been there and done that - and he didn't have any electronic junk to tell him that. He used common sense.

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So i guess mmcd was lying to me in all the logs i've done, and aem's uego wideband kit is an inaccurate piece of junk thats just a light show?

DSM1G90 said:

Open loop is when the ECU is not getting the minimum 177* reading from the temp sensor. Thus it's in open loop to run slightly rich - as B-DSM mentions .. and I've been there and done that as well with other vehicles where the T-stat has stuck open.

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For a 2.0 turbo this is true. However every vehicle's ecu programming is going to be different so its not necessarily true for every car on the road. Now as for the 1.8 this is not true. After the initial 1st minute of operation engine temp does not dictate open/closed loop operation. Rpm and throttle position are the sole dictators of whether its in closed or open loop.

DSM1G90 said:

You would think that when a vehicle comes out of the factory with 195* T-stats installed, it was for a very good reason WHY that range was installed in the first place.

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Higher temps improve economy. Its 195 t-stat from factory because thats how the computer was programmed to operate to reach the economy goals they set in place. Now once you start changing engine dynamics..you can't expect that same programming designed for economy to keep working properly. Maybe if the changes are small then yes the computer can adjust to an extent. A turbo system is not a small change. Its a huge power adder. Now you can't very well expect an operating system designed for economy to be able to maintain the power a turbo can add without eventually destroying itself. A turbo forces air into the engine. which raises cylinder pressures. Higher cylinder pressures generate more power and more heat. Heat is the enemy, it causes things to warp, bend, brake, and give out. Now that 195t-stat that was able to keep a stock engine at that temp, do you really think its going to be able to keep that same engine with a turbo at the same temp when your increasing cylinder pressures?

Closed loop is not determined in a 2g turbo either by engine temp. I've had it in closed as far down as 140*.

Sorry on all the fuss, but just going on stock form to help the OP out to get his ride in a good operational condition. Just been there and done that.

Good luck all - DSM

sounds like another 420a build.. if you dont dump a ton of money it wont be reliable if you wanna make power and when you do you still wont have traction

At least with larger cams and porting, the motor might breathe a bit better sinc the 4G37 is so undernourished when it comes to breathing.

Actually the head is pretty decent. The real restrictions are are in the stock throttle body, cam, and exhaust manifold.

Interesting piece of history. The 4g37 is an upgraded 4g32t, more displacement and an improved head design. The 4g32t back in the 70's i think it was, was mitsubishi's engine they used to compete with in racing events. Sometime in the 80's they retired the 32t and switched over to the 4g63t, since the rest of the competition was going with newer 2 liter engines. The 4g37, the engine itself was designed to be turbo, but they decided to use it as an economy engine instead since they had the 63 for their race engine.

sorry for the late update on the build but its getting towards the final steps waiting on the head to get back from the shop