Are our the 2.3L DISI Engines reliable?

[Karma_hunden]

Its been 53,000 miles since I bought my MazdaSpeed6 in 2006 and after blowing the engine on may after running 30,000 miles boosting 18psi (peaking on 20psi) with an short ram intake. Car was untuned. I was wondering, is it all my fault? or is the engine too weak?

I treat the car like a grandma, when I daily drive it. I do get in the ocational race. But im definately not one of those people that redlines the car just to catch up to traffic. (not a powershifter, nor I due digs anymore...try to drive the car a proper as possible)

A month after the new engine was put in, cruising at 75mph in 6th gear, the tranny goes out.

The car gave me trouble with some bad electric coils at the beginning, but ever since, it hasnt given me any problems till that dreaded day.

my friend had a heavy modified MS6 that he blew the engine as well. I hear people are blowing the engines even on stock ms6s.

Are these engines good at all? I dont think im liking boosted 4 bangers anymore.

 

[Evolved]

You had just a short ram intake and blew the motor???


Makin' me nervoussss!

 

[SMOKEYS36SHOP]

if he was peaking at 20 and holding at 18...sounds like he had either some kind of ems or boost controller.

 

[Evolved]

if he was peaking at 20 and holding at 18...sounds like he had either some kind of ems or boost controller.

Stock boost is right around 15-16, right? Would an SRI+TIP cause that to fluctuate?

 

[GoFast]

i think the key here is the amped up boost. I am fairly confident in saying that had you not upped it, it may not have blown. But, it's possible that you just got a bad engine. It happens.

 

[SMOKEYS36SHOP]

nope not at all. should still be the same..it helps it spool faster so it may peak higher for a second or 2..but it goes right back down to 15.6

 

[SMOKEYS36SHOP]

i think the key here is the amped up boost. I am fairly confident in saying that had you not upped it, it may not have blown. But, it's possible that you just got a bad engine. It happens.

yea i agree with the boost.. i am curious to see what else he had installed! also how often were his oil changes and so on. i know my car tends to break down my oil very quickly so its always dark

 

[GoFast]

yea i agree with the boost.. i am curious to see what else he had installed! also how often were his oil changes and so on. i know my car tends to break down my oil very quickly so its always dark

Well yes, maintenance could always be an issue but, just because the oil is dark doesn't mean it is broken down. It probably just means it was doing it's job and carrying away contaminants. I bet if you take a a sample of your oil next time you do an oil change and it get it tested, it will not be as broken down as you may think. I know I was shocked when my buddy showed me his results after having it analyzed. I used to be of the same thought train...dirty=broken down.

 

[Blendercloud]

If he was untuned, I have to assume he had no sort of engine management system. In order for him to achieve 18-20psi boost levels on a stock tune he would have to have some sort of boost controller. Of course, if you're running a boost controller without proper knowledge of how to incorporate one into a complete EMS you really up your chances of popping the motor.

I am an advocate that the clutch and transmission are the weak point on this car in completely stock trim. When people start to add things like boost controllers or even EMS that aren't properly configured, the stock engine internals become the weak link. I am curious to know what the OP and said friend consider "heavily modified".

I have a background of 13 years of dirt track and drag strip engine building and sometimes the things I see people expecting to get out of these engines/cars with a few thousand dollars is laughable. No engine is bullet-proof. No drivetrain lasts forever. Even if you do everything right when upgrading, any engine can pop at any time. If you're nervous or concerned about blowing up an engine, get a bicycle.

/endrant

 

[Neofolis]

I can't speak specifically for this engine, because I have not had mine long enough, but generally Japanese engines are the most reliable in the world. The build quality may not be as good as Germany, but reliability is usually better. The biggest difference between Japanese cars and those manufactured in some other countries, is that everything is adequate and no more. It will do it's job, but that's all it will do. The problem then comes that, if you modify one part of the vehicle, you are expecting another part to do more than it would do as standard. There may be many situations in which this is perfectly acceptable and will make little to no difference, it may just shorten the life of another part by a relatively small or un-noticable amount. On the other hand it could cause instantly noticable side effects.

As far as I am concerned, you can't criticize the reliability of anything that has been modified in any way. It was designed to work as it comes and is provided with no guarantees that it will work with any changes made, they are done at our own risk.

If you want to minimize that risk, you should either buy a car that has relatively simple mechanics and very few electrical/computerized components or buy something like a German car that is renowned for the quality of engineering and is generally built well beyond the specs that it needs to perform as standard.

All that said, I have mods installed, more on the way and many more planned.

I guess my verdict would be, as standard, I would expect the engine to be very reliable when compared with other standard engines, with mods, it is not likely the be amongst the most reliable engines when compared with other similarly modified engines.

Sorry for generalizing excessively, there are obviously many other factors that affect reliability, like quality/frequency of servicing, driving style and generally higher performance vehicles tend to be a little less reliable anyway due to the extra stresses they endure, despite being designed for that purpose.

 

[Karma_hunden]

Hey guys,

I had a manual boost controller. The car stock boosts 15.6psi; when I added the SRI it was boosting 16-17psi by itself which caused the MAF to light the CEL. After I upped the boost to 18psi, thats how I left it.

I am not a maintenace every 3,000miles guy. Syntetic oil is meant to last 6-9K miles. I changed my oil every 6,500 miles.

The temperature of that day also comes into play. It was a day at around 3pm, with 85-90 degrees out; so the air was hot and dense, and as we know, the engine cant breath right like that...the oil in it becomes dense and makes the pistons slide faster than usual as it overboosts. It was definately a bad combination because it sort of made the balance of the engine process deviate a little bit. Im guessing; im no mechanic. Im also guessing the MBC mightve overboosted accidently? I had a boost gauge but i wasnt watching the psi at the moment....so i dont know if i mightve boosted 30psi at the time of the incident...who knows.

I was doing around 85mph as i downshifted to 5th gear...went WOT till about 6,000rpms (the upped boost was holding up to 6K instead of 5.8K)...as soon as i shifted to 6th... BAM. Felt like someone threw a handfull of little rocks at my windshield, ticking noise started to sound, white smoke came out to the point i couldnt see anything in through my rearview mirror...like a flaming rocket the engine died, steering wheel went hard and i coasted to the side. This all happen at around 120mph, which is about the speed you shift into 6th.

i thought i had destroyed the tranny...or perhaps even the clutch, since it was at the moment of shift that it happen. but nope. it was hte engine alright.

my 'heavily modded' friend is registered here as MS6Mike...he was one of the first MS6's with turbo upgrade. Which was the one that came at the scene, and gave me a ride to my house.

I definately know im to blame, however, i think what i did wasnt too significant seeing as how Mitsu Evo owners do this all the time (up the boost with intake only and no tune). That's why im saying...is this engine too weak? I had also taken the bottom tray of the engine bay off for a better ventilation for less heatsoak around the engine bay, seeing as how mazda gave us the shittiest hood scoop.

 

[ms6z]

Jdm ftw....lol

i can't speak specifically for this engine, because i have not had mine long enough, but generally japanese engines are the most reliable in the world. The build quality may not be as good as germany, but reliability is usually better. The biggest difference between japanese cars and those manufactured in some other countries, is that everything is adequate and no more. It will do it's job, but that's all it will do. The problem then comes that, if you modify one part of the vehicle, you are expecting another part to do more than it would do as standard. There may be many situations in which this is perfectly acceptable and will make little to no difference, it may just shorten the life of another part by a relatively small or un-noticable amount. On the other hand it could cause instantly noticable side effects.

As far as i am concerned, you can't criticize the reliability of anything that has been modified in any way. It was designed to work as it comes and is provided with no guarantees that it will work with any changes made, they are done at our own risk.

If you want to minimize that risk, you should either buy a car that has relatively simple mechanics and very few electrical/computerized components or buy something like a german car that is renowned for the quality of engineering and is generally built well beyond the specs that it needs to perform as standard.

All that said, i have mods installed, more on the way and many more planned.

I guess my verdict would be, as standard, i would expect the engine to be very reliable when compared with other standard engines, with mods, it is not likely the be amongst the most reliable engines when compared with other similarly modified engines.

Sorry for generalizing excessively, there are obviously many other factors that affect reliability, like quality/frequency of servicing, driving style and generally higher performance vehicles tend to be a little less reliable anyway due to the extra stresses they endure, despite being designed for that purpose.

 

[Evolved]

I definately know im to blame, however, i think what i did wasnt too significant seeing as how Mitsu Evo owners do this all the time (up the boost with intake only and no tune). That's why im saying...is this engine too weak? I had also taken the bottom tray of the engine bay off for a better ventilation for less heatsoak around the engine bay, seeing as how mazda gave us the shittiest hood scoop.

Coming from having driven a modified Evo and now an MS6....they are two totally different cars that aren't really in the same class. The Evo has the 4g63 which is a motor SO well built, they barely changed it over the course of nearly 20 years. If you bought an MS6 with hopes that it would take mods or perform like an Evo, you should have done more research.

 

[Blendercloud]

Karma hunden,

Adding the intake did not increase the amount of boost your turbo delivers. The delta you saw between the stock-specified 15.6psi and the "16-17" that you indicate is due to your elevation and relative humidity in Florida. Furthermore, by manipulating your boost values manually, you caused such drastic overboost without advancing timing and increasing the amount of fuel delivered per revolution. Even further to that, you expected the engine to continue to swallow all that boost even near 6,000 revs.

The 4B11 used in the Evo 10 has a compression ratio of 9.0:1 versus the MZR DISI 2.3 Turbo's 9.5:1. Older Evos have used 8.8:1 compression ratios as well. That is one key reason they can boost signifcantly higher pressures. The series of engines that preceded the 4B11 have been in development for nearly 20 years and have taken a trial by fire in rally motorsports over the years.

Conversely, the MZR DISI 2.3 Turbo has been in development for about 4 years and has no motorsports experience. In that regard, the Mazda engine is inferior. However, the Mazda engine is noteworthy for providing enormous amounts of torque at low engine speeds, thanks in part to direct injection. The engine was initially developed to promote Mazda's new findings related to direct injection for conventional 4-cycle gasoline engines. It was one of the first of its kind to affordably portray the benefits of direct injection.

I encourage you, and anyone else reading for that matter, to firstly change your oil more often than that if you are pushing your car. Even synthetic oil should be changed every 3,500-4,000 miles if you're tearing into the car the way you described. Secondly, I highly discourage the use of any type of manual boost controller on these cars because of the very complex ways that the Mazda ECU manages boost, fuel delivery, valve and ignition timing, and wastegate operation. Literally tens of millions of dollars went into the development of this engine and its operation. You have to change the way the ECU operates the engine, not just manipulate the engine's components.

 

[Karma_hunden]

Karma hunden,

Adding the intake did not increase the amount of boost your turbo delivers. The delta you saw between the stock-specified 15.6psi and the "16-17" that you indicate is due to your elevation and relative humidity in Florida. Furthermore, by manipulating your boost values manually, you caused such drastic overboost without advancing timing and increasing the amount of fuel delivered per revolution. Even further to that, you expected the engine to continue to swallow all that boost even near 6,000 revs.

The 4B11 used in the Evo 10 has a compression ratio of 9.0:1 versus the MZR DISI 2.3 Turbo's 9.5:1. Older Evos have used 8.8:1 compression ratios as well. That is one key reason they can boost signifcantly higher pressures. The series of engines that preceded the 4B11 have been in development for nearly 20 years and have taken a trial by fire in rally motorsports over the years.

Conversely, the MZR DISI 2.3 Turbo has been in development for about 4 years and has no motorsports experience. In that regard, the Mazda engine is inferior. However, the Mazda engine is noteworthy for providing enormous amounts of torque at low engine speeds, thanks in part to direct injection. The engine was initially developed to promote Mazda's new findings related to direct injection for conventional 4-cycle gasoline engines. It was one of the first of its kind to affordably portray the benefits of direct injection.

I encourage you, and anyone else reading for that matter, to firstly change your oil more often than that if you are pushing your car. Even synthetic oil should be changed every 3,500-4,000 miles if you're tearing into the car the way you described. Secondly, I highly discourage the use of any type of manual boost controller on these cars because of the very complex ways that the Mazda ECU manages boost, fuel delivery, valve and ignition timing, and wastegate operation. Literally tens of millions of dollars went into the development of this engine and its operation. You have to change the way the ECU operates the engine, not just manipulate the engine's components.

Great write up Blendercloud. learned a few things there. Yes, I did assumed the fact I had it untuned was part of the mess/reason it happened; I just didnt know that it was THAT essential. I will definately go with a tune next time...I was just trying to make easy power, but as they say, easy come, easy go.

Yes, I know the previous EVOs had an iron block and all, and that it was definately stronger, but I thought that was usually more significant when heavily modding a car, not turning the boost up a few psi's.

BTW, quick question; dont wanna get off-topic with but just wondering. Which has a better engine now; the 2008+ STi's or the EVO X?

 

[Blendercloud]

The 'boxer' style engine that Subaru uses definitely has its benefits. The engine's inertia is evenly distributed horizontally in both directions. Weight is better distributed behind the front wheels. The crankshaft and other rotating components can be shorter. Unfortunately, the 'boxer' design falls short in one key aspect: gravity. Gravity will always cause the bottom portion of the cylinder to wear more quickly than the top portion. Compression rings and various bearings will not wear as evenly as they would in a more gravitationally-neutral environment like a V-4 or I-4 setup.

I would have to sit down and really study the engineered designs of both platforms before giving you any more than that. Just based upon what I've seen thus far though, if I had to choose I would choose the Evo 10's engine.

 

[zinger002]

is the 4b still the same material for the block as the 4g63?

 

[Blendercloud]

The 4B11 is a cast alluminum alloy versus the previous editions being a grade of cast iron.

 

[Karma_hunden]

Thanks Blend,

yeah, i heard the Evo community was shaking their head when they saw that the EVO X was going to have an aluminum engine. The 4g63 is bullet proof.

 

[Blendercloud]

Thanks Blend,

yeah, i heard the Evo community was shaking their head when they saw that the EVO X was going to have an aluminum engine. The 4g63 is bullet proof.

To combat the soft surface of aluminum, most will engineer an iron sleeve to go inside the cylinder as the mating surface for the piston and rings. This will help prevent cylinder warping and erosion as well as deck warping. I'm not sure if Mitsubishi did this or not on the 4B11.

The link below is a neat read if you're interested in learning just a bit more about cylinder block engineering. Granted, it's about slant six-cylinders. But it's well-written with great pictures and diagrams.

http://www.slantsix.org/articles/dutra-blocks/slant-blocks.htm