From what I have seen all older engines have lower compression than mroe recently installed engines, I know that the wearing of seals and bearing all contributes to this lower compression. But I am asuming that it is because of the extreme stress the turbos put on the motor. I am wondering if I am correct?

(now asuming nothing EVER went wrong with the car) Will a car with the proper suporting mods pushing 14 PSI on the stock turbo system making roughly 350RWHP slowy decrease in power even though it is still running the same boost levels because the compression is lowering due to the wear on the engine? Also in following this theory will a car pushing 12 PSI with the proper supporting mods making 320RWHP keep it's power and compression longer than the engine running 14 PSI. (this is also asuming both cars were driven the same way over the same amount of time, fairly hard...)

I think I have put this question the right way but if I left anything out just ask me what is confusing and I will try to clear it up. I am just wondering if loss in power and compression over time is a direct result in pushing higher levels of PSI into the motor. Thanks
-Nic

 

"The light that burns twice as bright burns half as long."

 

more boost =more heat +press--->flatter springs=less sealing capabilities,thus less power

 

so people pushing tons of power are just asking for an engine that is not going to last (power wize) regardless if nothing brakes on the car

 

I really like that. It encompasses your whole thread in just a little line. That's awesome. Why dont we try some theory to practice though and have somebody run like 40psig, and we'll see how long till his engine blows. Any volunteers? I'm kidding, please dont jack up the boost because I asked for somebody to experiment.

 

I dissagree in principle with the light thing

All depends on the mods you have and how you have taken care of everything

More boost, all else remaining equal will increase engine wear...I agree...but more boost with bigger IC, more fuel, cooler intake etc. etc. should create no more wear than stock

However, in practice, as it is very difficult to make all these new items work correctly, and because often we push things to the limit, we end up increasing engine wear

 

so if someone (God of engineering...) could develope even stonger seals the engine would last longer regardless of boost levels, still asuming everthing else stayed the same

 

Having peripherals like an IC and having your a/f ratio correct will not have an effect on engine wear-- the increase in combustion chamber pressures and resultant higher stress on the sealing surfaces from running higher boost will. If the internal engine parts were not initially designed with a lot of overkill in mind (which many of the 13B-REW components obviously weren't, as many of us have found out), their life expectancy will be shortened considerably.

 

Negative, because you're overlooking the other parts that are subject to wear and tear in the engine. The stock apex and side seals are often labeled "weak" because they can't withstand the effects of detonation, but it has nothing to do with their life expectancy under the running conditions they were originally designed for. Stock NA rotaries will last for over 150K easily if cared for correctly.

 

Also I heard someone mention the springs?? So if really good springs were created that would help the situation no?

 

Which seals exactly in the motor are the ones that are responsible for lower compression of the motor once they have endured too much wear?

 

Apex and side seals, and the lining of the rotor housings.

 

Right but asuming the engine never experienced detonation... will or can an apex seal crack strickly due to prolonged wear from high PSI levels in the motor over a certain amount of time?

 

It's not that simple. You may run into problems with excessive drag on the seals/housings, which could cause a whole host of problems.

 

They can, because the parts were not designed to endure that type of combustion pressure in the first place. The apex seals don't have to "crack" to leak.

 

Seals break, and/or they wear out. There is a big difference. Putting too much pressure on the seals will cause them to wear more quickly, or break. If they break, you are screwed right away. If they wear quickly, your car will still run good. It will smoke, and burn a lot of oil, but it will still go like hell ...... until it stops.

A car with worn seals may still run pretty good. Of course, if you are behind it, you may not be able to see the car

 

The light that burns twice as bright, burns half as long. And you have burned so very very brightly, Roy.

Dr. Eldon Tyrell : Bladerunner

 

Funny how everyone focuses on apex seals, as if they were the only part of the engine that could experience wear or breakage...

 

True, but historically, don't they lead the pack for point of failure?

 

how about differently shaped apex seals (where they scrape the housing)? closer rotor-to-housing tolerances (if thermal expansion would allow)? double up the side seals like having multiple piston rings?

total shot in te dark here, but maybe teflonish internal coatings if they could handle the heat, to of course, reduce friction and hopefully increase life span?

best thing would probably be to just up the displacement so that you aren't pushing the motor so hard to make hp. rotaries can make a bit of hp out of 1.3 ltrs, but they aren't magically exempt from the benifits of more displacement.

when you are running 400 hp out of the REW you are almost doubling the cumbustion pressures i'd assume. something has to give sometime.

 

Flame Away !

So if you use 3mm seals you're reducing the stress placed on the 2mm seals due to more "Girth"
Also 3mm seals have a larger surface area against the rotor houseing, which doubbles wear, but only if you increased the RPM by a factor of 1.5 or 150%.. over stock... but also the larger area against the rotor face, would mean it would take longer for low compression to occur since it would take longer to rub off the same mm distance of a 2mm seal. ??

I know the debate has raged for years now... my point in this is if you increase boost, there is some wisdom in beefing up the structual parts that are prone to failure... wether your motor goes due to wear or apex failure, personally if my compression falls seriously short, I'll start experimenting with my ECU some more to learn how to tune, but thankfully that won't be for quite some time (crosses fingers)

 

Neuton's Law:

"For every Action there is an equal and opposite Reaction"

 

every engine known to man will burn out quicker with more power... think of a top fuel dragster engine, it has a life span of just under 5 seconds :-D

 

3 mm apex seals were discontinued as stock by Mazda because they were bouncing too much when transitioning over the exhaust port. The lower mass of the 2 mm seals helped to reduce that, and better springs may have helped as well.

2nd gen N/A engines routinely last 200K mi. They fail for many reasons, but the apex seals will crack when they wear too thin. Many of the cars were trashed when the compression dropped low enough that they flooded. Ill imformed owners and poor knowledge at dealers contributed. A 15 year old car doesn't get much respect!

Any engine that is modified to produce more power will have a theoretically shorter life. Whether it results from higher wear or not is a matter of chance. Often it's a minor part that fails and causes catastrophic failure as everything in the power train is operating closer to or over "the edge". Running stock power the engine may have survived that minor failure.