Pistons and Rods 3a92 discussion

[PityOnU]

Sorry you're having a hard time finding information.

Most people on this forum are from English-speaking parts of the world. In those markets, the Mirage is very much an underpowered econobox. Parts are also fairly expensive. You will find very few people here who have ever eyeballed a Mirage with performance tuning in mind.

There does seem to be a decent amount of Mirage tuning going on in the Southeast Asian countries the vehicle originally targeted. You won't see many posts about that here, though.

[Loren]

If I had to guess, I'd say you're one of maybe 2 or 3 in the US doing it. A handful more in various parts of Asia. And they all tend to be either tight-lipped, not fluent in English, or just not responsive to communication.

I feel your pain. I went through the same thing with suspension parts. Once you get past "coilover kit" and "rear swaybar", there's not much more available for these cars.

[DirtGearTv]

I’m torn guys... I could A. tear everything down and start gambling with mismatched rod and pistons Or B. Leave the rods/pistons well enough alone and never get too serious on boost.

Here is what I know according to our Asian friends. Some claim to be running as much as 17psi with only low comp pistons. My thought on that is as long as i’m on e85 and careful with my tune deto shouldn’t be a factor, which is typically what would melt a piston anyway. IMO the rods are a weak point far before the pistons (if deto is off the table). So if these guys are getting away with 17psi on stock rods surely I should be able to run 10 continuous and 15psi spike now and again as long as my temps are low. I want to say that is safe given the info I have from others, but really who’s gonna know until a clown like... me... pushes things too far. I’m sure y’all would love for me to tear it down all the way and crank up the boost but i’m not super confident in being able to match rods and pistons without a lot of time and money...

Well those are my thoughts for today anyway. Tomorrow I might change my mind

[Loren]

I don't know what the landscape of the head looks like, but you could reduce compression a little bit by shaving some material INSIDE the combustion chambers.

I agree, the rods are probably fairly weak. If they are anything like the valves... they're made to be as light as possible and still get the job done.

But, if you're tuned right... other people are pushing 15-17 psi... I'd think you could get away with 10 psi.

If not, blowing stuff up in the name of science is cool, too.

[Pimp_Daddy_Patty]

If running more than 12 psi, I would gap the rings larger at least. I've had ring land failures at around 12-14 psi. The same motor with larger ring gaps held 18psi no problem for the rest of that car's life. This was a Dodge 2.0L DOHC engine.

One other concern I'd have with some recent engines is the ring lands are thinner/shallower to help with emissions. This may or may not be the case with the 3a92.

I'd be tearing into these things much sooner if I wasn't already commited to another project.

[DirtGearTv]

If running more than 12 psi, I would gap the rings larger at least. I've had ring land failures at around 12-14 psi. The same motor with larger ring gaps held 18psi no problem for the rest of that car's life. This was a Dodge 2.0L DOHC engine.
One other concern I'd have with some recent engines is the ring lands are thinner/shallower to help with emissions. This may or may not be the case with the 3a92.
.

Is this an aluminum block?

[Pimp_Daddy_Patty]

Is this an aluminum block?

Cast Iron

[Alex1a1f]

Cast Iron

In our 3A92? Or Dodge 2.0L?

[DirtGearTv]

In our 3A92? Or Dodge 2.0L?

He means the dodge. Our 3a92 is aluminum block no sleeves. Where as ring gap still important, maybe not as critical with the aluminum expanding more with higher temps

[allrock]

if you want more power i think it would be cheaper just to replace the whole engine, the 4G15T from the colt ralliart is i think the best option to put on a mirage, its just a 1.5L engine but already turbo charged, maybe when mine gets old i would do that.