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2G 2G Stock Waste Gate Spring?

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jpfrk2001

Probationary Member
12
0
Aug 20, 2020
Peculiar, Missouri
Hello all,

New to this forum, not new to Auto performance Tech.

I wanted to know if anyone out there knows what the factory Turbo Waste Gate spring is?

My car is the 1997 Mitsubishi Eclipse, GSX AWD mode.

The car is Bone stock with zero Mods ( for now).

I just want to know so I know what spring to start at when I install my Hinagwa WG setup.

I will be keeping it below 15 lbs of boost. Depending on the stock spring, I was thinking of a 12 or 14 lb spring.

Of course this will be done when I install the full 3" turbo back exhaust system I plan on getting at STM Tuned.
 
People claim different rates. This is what the FSM shows & may help.

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I believe it’s 7psi.

You could go the spring route or just get a simple manual boost controller

Before I blew my stock T25 I was running 12-14psi I think the highest I ever saw was 17 but it runs out of steam and drops off up top. If you’re planning on upping the boost I would recommend getting a wideband AFR gauge so you know when it starts to lean out and don’t fry valves, melt things etc... stock injectors can only handle so much airflow.
 
Thank you for the info.

I know about the wideband AFR thing. I am really hoping to keep the interior as stock looking as I can. I want the spring route due to being more reliable and not finicky. I will throw a 12lb spring to start with and see what happens I guess.

I tried the manual boost controller route on other turbo builds and they were always finicky. I even sprung for an actual name brand unit and it was just finicky.

Thanks!
 
Thank you for the info.

I know about the wideband AFR thing. I am really hoping to keep the interior as stock looking as I can. I want the spring route due to being more reliable and not finicky. I will throw a 12lb spring to start with and see what happens I guess.

I tried the manual boost controller route on other turbo builds and they were always finicky. I even sprung for an actual name brand unit and it was just finicky.

Thanks!

I know what you mean about the MBC. Do a pull, get out, turn a quarter turn, repeat a million times LOL. And of course the temptation is always there to just crank the damn thing all the way up LOL . 12psi should be safe. Let us know how it goes! Should be fairly quick yet reliable.
 
If you're planning on staying close to stock why not plumb the wastegate lines through the OEM boost control solenoid & let the stock ECU control boost. The factory setup shouldn't care who's wastegate you're using, internal or external.
 
If you're planning on staying close to stock why not plumb the wastegate lines through the OEM boost control solenoid & let the stock ECU control boost. The factory setup shouldn't care who's wastegate you're using, internal or external.

Very true, but, then what is the factory ECU settings for Max boost the ECU will allow the engine to see before the controller goes full open?

I understand electronic boost solenoids, I plan to run one on another project, but the stand alone unit I using has the ability to program boost by RPM, Gear, two step, etc.

This car I won't by pass the stock controller, I am just taking over control from the ECU using mechanical means.

This car is my DD, but I like to have fun on the way to work and home sometimes. so reliability is important.

I am aiming for about 300 at the crank using the post on this site outlaying all the proper steps for 300.
If you're planning on staying close to stock why not plumb the wastegate lines through the OEM boost control solenoid & let the stock ECU control boost. The factory setup shouldn't care who's wastegate you're using, internal or external.
 
Typical boost is around 12 psi but the ECU algorithm doesn't exactly work off of boost pressure. Are you still & planning to use the stock MAF setup? The ECU monitors the volume of air, throttle position, etc. & inject the programmed amount of fuel to achieve the targeted performance. It will be close but you may reach "fuel-cut" trying to obtain 300hp.
 
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Stock will be 7-8psi. I also recommend starting there and controlling boost either with the ECU or a manual boost controller. That way you can get your tune ironed out with low boost before you begin to crank it up. You don't want to go straight to 20psi with an unknown tune.

The computer will usually end up allowing 11-12psi on a stock setup.

The stock spring and a boost controller will get you to 18-20psi of boost before it can no longer hold the gate shut. It will build even more if you have a free flowing exhaust and allow it to creep. Mine spikes to about 24psi, and creeps up closer to 30 by redline, but I am on a holset WGA (~18psi gate pressure) and a 20g. My philosophy on these smaller turbos is just to let it creep and have plenty of fuel injector to tune for it.
 
Typical boost is around 12 psi but the ECU algorithm doesn't exactly work off of boost pressure. Are you still & planning to use the stock MAF setup? The ECU monitors the volume of air, throttle position, etc. & inject the programmed amount of fuel to achieve the targeted performance. It will be close but you may reach "fuel-cut" trying to obtain 300hp.

Right now I do plan on keeping the MAF. I don't have any plans to hack into the factory engine wiring and using piggy back products. I know I am really limiting my self with this rule. This car is so clean and un-molested, I want to keep it that way. Just a bit more boost under 14lbs reliably.

Stock will be 7-8psi. I also recommend starting there and controlling boost either with the ECU or a manual boost controller. That way you can get your tune ironed out with low boost before you begin to crank it up. You don't want to go straight to 20psi with an unknown tune.

The computer will usually end up allowing 11-12psi on a stock setup.

The stock spring and a boost controller will get you to 18-20psi of boost before it can no longer hold the gate shut. It will build even more if you have a free flowing exhaust and allow it to creep. Mine spikes to about 24psi, and creeps up closer to 30 by redline, but I am on a holset WGA (~18psi gate pressure) and a 20g. My philosophy on these smaller turbos is just to let it creep and have plenty of fuel injector to tune for it.

I do plan on a larger 3" full exhaust on the car. The rule is no hacking, 100% bolt on, no permenant mods that I cannot undo. As said above, this car is super clean. No mods, one owner car, I found it for sale last year with only 61k miles. I do realize I found a true Diamond. Im not screwing this up.

I will just do a 12 lb sping to see what happens. Its still below the 15 lb danger limit where larger injectors and programming mods using piggy back systems.

But I really have to admit, I don't really know what these stock ECUs are capable of. I've heard OBDII can be a headache.
 
But I really have to admit, I don't really know what these stock ECUs are capable of. I've heard OBDII can be a headache.

You can run speed density with a flashable "black box" ecu, or convert to an evo viii ECU. Both easily reversible to stock and you won't be married to your MAF.

I have the same "bolt-on only" policy on my car, everything must be easily returned to stock. Luckily its easier on a 1G since I can just use link.
 
You can run speed density with a flashable "black box" ecu, or convert to an evo viii ECU. Both easily reversible to stock and you won't be married to your MAF.

I have the same "bolt-on only" policy on my car, everything must be easily returned to stock. Luckily its easier on a 1G since I can just use link.

Do you have a link to this "black box" and supporting hardware and software? I am interested as long as this is 100% bolt on. Zero cutting wires. I even want to stay away from wire splicing.
 
So I found an interesting thing while working on the car.

I needed to swap out both O2 sensors, and while I was on it, I installed my Cold Air kit, and swapping out the factory WG for an aftermarket unit with a higher spring rate. I went with 0.8 BAR spring

I connected all boost reference lines backup like factory as well.

I found the WG Swing Valve was stuck halfway open!! It was stuck pretty bad. So that would explain a large loss in power. PB Blaster with 2 days of working it, and its free like it should.

The added power was crazy!! And my Fuel Economy has improved a lot as well.

So, I am thinking of swapping the spring for a 1.0 BAR.
 
Might as well keep this thread going.

Another question about the stock ECU capabilities?
Will the factory ECU read and accept a 3 BAR MAP?

The way it works, the 3 BAR just widens and expands the voltage out put based on pressure input.

Basically a 2 Bar goes from -14.7 to 14.7 lbs of boost. So the voltage output would be 0.1V to 5.0V across the range.

A 3 Bar just widens that range.

Of course I will be going 440 CC injectors and a larger 3" turbo back exhaust.

When I swapped to a 12.5 lb spring, The ECU gave no hiccups about it.
 
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