Can anyone guide me to the right sections to read about redliens and stuff. i wanna learn about it and wonder if it is possible to increase redline to a higher number?

 

short answer: yes, but you have to upgrade your valvetrain and get rid of the rev limiter though.

 

It's possible, but at this time, not advisable at all...

There aren't enough engine modifications developed to strengthen your engine to handle the high RPMS...

 

valvetrain aside, what can the bottom end handle as far as rpms due to the gargantuan stroke (96mm?). I would think the motor would have to be destroked to be able to rev significantly higher anyways right?

 

i have made dump mistakes and down shifted and caused it to rev to 8500 and something, it was loud but no issues took off the oil pan and no shavings so no spun bearing its all good in the hood YO lol



just dont know if it can handel it light to light like a b18 or a k20 but at this current point in time we need to focus on increasing the power band to streatch past our current redline

 

I think the "normal" limit on most production engines today is around 22 m/s piston speed. I could be a little off, and it will vary a tad from engine to engine depending on design. For example, some acuras I believe are running upwards of 24 m/s. The tC redline is 6250 I think. With a 96mm stroke that is hitting approximately 21 m/s piston speed. So without shortening the stroke or coming up with some very strong internals you wont reliably go a lot higher.

Piston speed is the speed in m/s (or feet/min in some calculations) that the piston is moving for a given rpm based on stroke length. The internals (crank, rods, etc) can only take so much strain, so there is an upper limit for a given design. This number and the properties of the design elements give a good indication of the maximum "safe" rpm for an engine.

Ways to increase this safe limit are stronger internals, lighter rods and pistons or shorter stroke. Or a combination of these

 

^ good info can i get a link so i can read up on stroke more?? or do you just want keep spilling info here for me??

 

I have looked around before and found some interesting links. Here is one I really like:

http://me.queensu.ca/courses/MECH435...erformance.ppt

A lot of good info on there. I actually used a formula involving f/m to do my math, so the conversion rounding threw it off a bit. It is actually about 20 m/s for 6250 rpm on the tC.

 

If your looking for high redlines...

cough cough...ROTARY!!!

An '86 rotary came out of the factory with a redline of 7000. With somewhat cheap mods, say $3500-5000 you can get it to spin at 10K (Ffrom what I have heard, if someone knows otherwise please inform)

Although, if you don't care about rotary's dont study them because they will only confuse you and make you envious of thier awesomness,

 

Envious of their reliability...
Just like my DSM...

 

Not sure where everyone got that they are so reliable (the wankel engine). Yes, the rx7 was a overall reliable car, but the apex seals had issues from the factory and needed to be upgraded in order to make them reliable. They also went through fluids fairly quickly. so they did have thier downfalls. I think they were great cars, but I wouldnt put them up there with the most reliable... more than any DSM I have seen... but I have never seen a reliable DSM No offense to any owners out there..

But on the wankel, they HAD to produce high rpm to produce power. Now, give me an engine with high torque numbers across the band with a 9000 rpm redline and I will pee myself :D

 

^^^^dont forget the big fires the wiring harnesses give... it gives a few days of enjoyment, laughing with your buddies. Rebuild every 80k got to love it.

 

I think there was a touch of sarcasm there. lol

BTW,
Good find with the ppt presentation. I'm saving that one

 

^^ yeah, I thought that on the sarcasm

That is a really good power point. I just stumbled upon that one. If you feel like doing the math, then you could find out the weight of the tC rods and pistons, then use the inertia formula and piston speed calculation. You could then figure how much lighter you would need to make the components for a given increase in rpm. Being the geek I am sometimes I may have to sit down and do that one But, you have to keep in mind that the basic frictional forces at play also have an effect as well, so certain other limits are in place.

 

whoops sorry you would be amazed though.

 

i was going through it last night till like 10 pm but i had to stop. thanks though this will help alot with my Dseries project

 

Now wait a minute, I will agree that the apex seals are junk on the third gen, but my 86 RX7 has 120K miles on all original engine parts. Never rebuilt and won't need to be untill 160K miles. The wankel does go through oil at a faster rate because it injects oil on to the seals so they don't burn up and to get a 100% seal.

But I have to agree with you on the reliable part. Of course, no purpose built sports car is supposed to be reliable. Im not saying the RX7 was 'purpose' built, but its not meant to be a family car.

If you get a NA Wankel, they are somewhat reliable. If you get a Turbo yur looking at a breakdown every 20K miles. However, wankels are better for Ultra High power. Say 600 HP+, a wankel will last longer then any piston.

 

Chevy 302? Maybe not much low end though? But for the day pretty impressive.

 

Now that was one hell of an engine as well. Fast revving 300 + HP NA straight out of the box. What was cool was how they rated its HP from the factory at almost 2000 rpm below its real performance point :D