2004 MSM, spun rod bearing, I think...

[dfwcouple]

I can remember when I first brought the MSM home from the dealer and told my wife I had bought a Miata. She was almost disgusted saying that was a girl car and she don't like them, then she saw it and could not believe it was a Miata. She really liked the flippy thing in the back, you know the spoiler. The car has served me very well to get me back and forth to work, and the weekend date car, but trouble was brewing in paradise, all good things come to a end, or pause.



Well now over the years I have put over 100K in miles and have spun a rod bearing, thought it would last longer, but what you going to do. I looked around DFW in Texas for a shop and found Running Performance which specialize in Honda performance, but they all work about the same, so I sat down with the owner Izzy, and we went over the repairs. The plan is to go with Wiseco forged pistons married up to Eagle H rods, performance bearing to increase oil flow, change the oil pump, timing belt, and water pump. In the future I may want a little more boost, but I can say the car had great performance with excellent handling from the factory.

During the inspection of the car we started it up, and it purred like it did when it was new, but you give it a little gas you'll hear a low end knock. Izzy said that I was it sound like a rod bearing. During the tear down he is going to verify this, along with checking the block, and clutch. He then made a comment on my throttle inlet tube, I had done a redneck repair job with a roll of gorilla tape , at this point I found he made custom turbo tubing for cars, this will be no problem to fix.



I am going to keep this tread open through the repairs, I also guess this would be a great time for suggestions for small changes that could help in not only performance, but gas mileage, HP is great until you hit the pump.

[dfwcouple]

I talked with Izzy today at Running Performance and he says he will have the engine out by tomorrow. He is also going to send me picture updates with the progress, and damage I have caused. I will keep you posted as long as they don't lock this thread. Once I have the car back I will update this site with proof of ownership.

[Mr. Miatie]

Sorry for your troubled times. Hope it works on for the better in the end.

[dfwcouple]

Sorry for your troubled times. Hope it works on for the better in the end.

Well I have been wanting to add a few mods to the car, perfect time to do it.

[SirHustlerEsq]

Did he check lifter-lash?

Dropping to 8.5:1 compression?

[wizzurp]

For reference, izzy is a good guy, he knows how to build stuff, your car will make power if you want it to when he is done with the internals.

[dfwcouple]

For reference, izzy is a good guy, he knows how to build stuff, your car will make power if you want it to when he is done with the internals.

Thanks, he seems pretty good, easy guy to talk with.

[dfwcouple]

Sorry for your troubled times. Hope it works on for the better in the end.

Its all good, Running Performance got the oil pan off today, bad rod bearing on the last cylinder.

[dfwcouple]

Did he check lifter-lash?

Dropping to 8.5:1 compression?

I don't even change my oil anymore, also if you drop your compression, won't you lose low end torque.

[dfwcouple]

Latest update on build from Izzy at Running performance.

[dfwcouple]

So now I am thinking of ways to get a little more power since the car will have a forged bottom end.

[Walsted]

So now I am thinking of ways to get a little more power since the car will have a forged bottom end.

Probably way out of my league, here, since I was a Ford Turbocoupe guy, not a Mazdaspeed guy, but if it were me...

First, I would look at the OBDII operation, and see if increasing boost or changing compression would throw a code causing an inspection failure.

If not...

If the engine has forged internals, including pistons, I'd look at lowering compression and making up for it with increased boost, provided the injector bandwidth was adequate to keep up with the increased boost given a good enough fuel pump. or the availability of a a fuel pump that could keep up, such as a Walbro 255lph high pressure. The thought process here is that power is provided by the mass of expanding air. For example, 20PSI of boost in a lower compression engine has a slightly higher mass than 20PSI in a high compression engine of the same displacement, meaning more expanding gas upon ignition for the lower compression engine and thus more power.

The Turbocoupe I had was 10psi/155 hp stock; increasing the boost to 20psi and adding the 255lph hp Walbro made it a LOT more responsive, since the fuel pressure regulator was vacuum/boost regulated, and the higher performance pump could keep up until redline in theory. (I never tested it, since that would have been over 170mph. Never had it dyno'ed for actual numbers, but the difference was extremenly evident.) I wasn't worried about the boost pressure, since some guys were running significantly higher than 20psi on forged pistons, (with bigger or more injectors) without ill effects until they had to pay for gas.

In the Turbocoupe world, boost limits are primarily determined by pistons and fuel. Cast pistons (even hyper-u) don't last at more than 10psi on those cars. On the other hand, this may not be true for all cars, since I have seen a reference to turbo Solstices running 18psi on cast pistons. Stock fuel pumps often can't keep up with high boost, which results in pinging and holes in the pistons in the Turbocoupe world.

The general rule of thumb with a TurboCoupe was a pound of boost equals six to ten ponies, probably closer to six. On the other hand, and better for us, a guy I met at the Wednesday night DFWMiata meet told me that the turbo gave him more than 10 horses per pound of boost on his Miata. If that is true, and I could run 20psi on a Mazdaspeed compared to its stock numbers, how much would my gas and tire bills go up if I had a Mazdaspeed?

The folks who know more about Miatas and Mazdaspeeds can probably give you more applicable advice, especially about fuel injector limitations and fuel pressure regulators. Intercoolers also come into play, but the cast/forged switch doesn't affect intercooler choice as much as it does the "how much boost will I run" decision.

I hope this helps, even if the knowledge comes from a different turbo'd car. Hopefully, a bunch of knowledgeable folks jump in and tell me how much and where I am incorrect or it is different in Mazdaspeeds, so we can all learn.

[wizzurp]

Ouch, that bearing is toast. Time to have her machined and get some fresh bearings and your forged internals in her!

[SirHustlerEsq]

I don't even change my oil anymore, also if you drop your compression, won't you lose low end torque.

Not if you tune for it.

[SirHustlerEsq]

but the cast/forged switch doesn't affect intercooler choice as much as it does the "how much boost will I run" decision.

Depends on the turbonator. Small turbos move less air than large turbos at a constant manifold pressure.

[dfwcouple]

Ouch, that bearing is toast. Time to have her machined and get some fresh bearings and your forged internals in her!

Working on it.

[dfwcouple]

Probably way out of my league, here, since I was a Ford Turbocoupe guy, not a Mazdaspeed guy, but if it were me...

First, I would look at the OBDII operation, and see if increasing boost or changing compression would throw a code causing an inspection failure.

If not...

If the engine has forged internals, including pistons, I'd look at lowering compression and making up for it with increased boost, provided the injector bandwidth was adequate to keep up with the increased boost given a good enough fuel pump. or the availability of a a fuel pump that could keep up, such as a Walbro 255lph high pressure. The thought process here is that power is provided by the mass of expanding air. For example, 20PSI of boost in a lower compression engine has a slightly higher mass than 20PSI in a high compression engine of the same displacement, meaning more expanding gas upon ignition for the lower compression engine and thus more power.

The Turbocoupe I had was 10psi/155 hp stock; increasing the boost to 20psi and adding the 255lph hp Walbro made it a LOT more responsive, since the fuel pressure regulator was vacuum/boost regulated, and the higher performance pump could keep up until redline in theory. (I never tested it, since that would have been over 170mph. Never had it dyno'ed for actual numbers, but the difference was extremenly evident.) I wasn't worried about the boost pressure, since some guys were running significantly higher than 20psi on forged pistons, (with bigger or more injectors) without ill effects until they had to pay for gas.

In the Turbocoupe world, boost limits are primarily determined by pistons and fuel. Cast pistons (even hyper-u) don't last at more than 10psi on those cars. On the other hand, this may not be true for all cars, since I have seen a reference to turbo Solstices running 18psi on cast pistons. Stock fuel pumps often can't keep up with high boost, which results in pinging and holes in the pistons in the Turbocoupe world.

The general rule of thumb with a TurboCoupe was a pound of boost equals six to ten ponies, probably closer to six. On the other hand, and better for us, a guy I met at the Wednesday night DFWMiata meet told me that the turbo gave him more than 10 horses per pound of boost on his Miata. If that is true, and I could run 20psi on a Mazdaspeed compared to its stock numbers, how much would my gas and tire bills go up if I had a Mazdaspeed?

The folks who know more about Miatas and Mazdaspeeds can probably give you more applicable advice, especially about fuel injector limitations and fuel pressure regulators. Intercoolers also come into play, but the cast/forged switch doesn't affect intercooler choice as much as it does the "how much boost will I run" decision.

I hope this helps, even if the knowledge comes from a different turbo'd car. Hopefully, a bunch of knowledgeable folks jump in and tell me how much and where I am incorrect or it is different in Mazdaspeeds, so we can all learn.

Well I am not going to lower the compression, there is a fix that will allow you to turn up the boost on the factory ecu, but you can not go above 12 psi on the factory injectors, factory boost is about 8.5. I have never heard of 20 psi on a miata 1.8 liter, that sounds really extreme, plus I still want to drive the car, not look at it for fear I will blow it up.

What I have been thinking about once I get the this rebuild done, first I am going to replace the factory exhaust all the way to the downpipe and install a more efficient turbo than the factory one. I was also looking at replacing the turbo plumbing with a new intercooler and intake. Lastly looking at putting in 330 to 400 cc injectors, would hate to end up with holes in them brand new pistons. Way later down the road I think I want to reflash the ECU, or go with a MegaSquirt if we move to the country as planed were they no longer OBII test the car.

Once again I have to say I am new to all this turbo stuff, last time I built a car, we still used carburetors, displacement was king, and gas was cheap. All post are welcome.

[SirHustlerEsq]

You need to get on Miataturbo and start reading. It will help you get away from carburator logic to EFI logic.

[Magma]

I opened up the breathing and exhaust on mine with a better intake/downpipe and exhaust. With the stock electronic boost controller, I can consistently see 10.5-11psi

[dfwcouple]

You need to get on Miataturbo and start reading. It will help you get away from carburator logic to EFI logic.

Yes I know, they are making more power at of these small engines, than I ever thought possible back in the 80's. If you go back and look at the muscle cars we dreamed about, they really didn't have that much HP. EFI has made a huge difference in tuning giving you the ability to make more with less.