you guys jacked this thread!

 

there is not only one equation for everything...or rather, maybe there is, but there are different forms of it. it is very useful to have specific forms for different situations.

actually... F.V is the vector form, whereas work/time is a scalar equation. (although both produce a scalar answer)

pat

 

i really dont think we need to bring in that level of physics to describe the fact that Horsepower is what determines acceleration, lol. We are going a little beyond our topic.

And yes! Karack is right, omg what have we done! hahah sorry, i was going a little nuts.

TIME TO UN-JACK THE THREAD! (thats a funny pun, becasue my name is Jack, so me "Jack-ing" a thread is pretty funny.)

As far as the lifespan at redline, id say the biggest determinant is the skill of the engine builder.

Go to someone you trust and who has alot of experience if your car is going to be undergoing alot of stress, and make sure you break the motor in properly. The seals they use will be up to them; talk to your engine builder and have them explain their reccomentation do you.

If you are going to be building the motor yourself, i wish you luck if it will be seeing alot of high stress. Check your clearances veeeery carefully. try to get some tried and true porting templates from someone.

Through no experience of my own i would reccomend the Atkins seals. This is only based on what i have heard from people who *have* rebuilt motors.

I have not rebuilded or ported motors, so i do not know all about it haha

 

And all of the above calculations of force, work, power, etc. are integral equations (or differential, depending upon how you would like to look at them). It's basic calculus. The only reason that I mention this is that the forms of the equations that you are using are *very* limited in the scope of their application. For example acceleration is not simply velocity divided by time. Acceleration is the rate of change in velocity at a point in time. In other words

a(t) = dV(t) / dt , not a=V/t

BTW, Ted - that bit about power not being a measurable quantity is absolutely wrong. I didn't expect that sort of thing out of you. By your own definition current itself is not directly measurable but is calculated from the field effects it produces.

One thing that I have not seen mentioned, and is actually topical - is the tradeoff off of torque for (wheel) velocity via gearing. The actual torque that you will see at your wheels (which does determin your acceleration at that point in time) is a function of the output power of your engine coupled with the gearing. This comes into play whenever you are selecting tranny ratios and shift points and need to know how they will match up with the engine output.

-bill rankin
(adj. assoc. professor, duke univ. dept of electrical engineering)

 

back on topic, i have rebuilt engines with both RA and atkins seals...the atkins broke in somewhat faster, but other than that i never noticed any difference... its hard to tell, since the RA are new, but i still think that any seals will be fine for normal redlining. if you are talking about running at high rpms comtinuously, like a bridgeport, then RA does not recommend their seals, while atkins are supposedly fine.

pat

 

actually you described what i was trying to say far better than i did.

i really really didnt want to go into calculus, i want people who are reading this to be able to understand it, so thats why i was speaking in fundamentals.

Not everyone has taken even basic calculus. Differentiation and Integration, to them, are foreign concepts.

You dont have to tack your title on to the end of your post for credibility, we know you are correct.

-Jack Glanzrock
some random student, Central CT State Univ., dept of mechanical engineering

P.S. hit me up on AIM and we can hash this out using the calculus rather than dimensional analysis. Leibnitz would be proud.

And maybe you can help me with some of my tests coming up

 

totally glad i failed math every year of my life

 

Hmmm (rats, back on topic again ;-) IIRC, the only item in their rebuild kit that RA recommended not to use (for high output high RPM engines) were the short and long apex seal springs. They recommended using the OEM springs instead because the OEMs were better heat treated.

At least this was my read after scanning through several very long threads on the RA seals and rebuild kits.

-bill

 

^^^ true, i had forgotten.

- Pat Wildfire
also random student, West Virginia U. Dept. of Mechanical and Aerospace Engineering.

i want in on this physics argument...lets start a new thread and paste it all over...lol

actually...its too bad we got into this in someone else's thing... this info might actually be useful to some people, or at the very least, interesting

What year are you, jack?

 

Yeah, I ignored the first semester of Calculus, or else we would'de lost a lot of people.

Yes, you're right, it's differential caluclus.
velocity = delta (distance) / delta (time)
acceleration = delta (velocity) / delta (time)

Current can be "measured" by an ammeter (via field effect).
Horsepower still can't be "measured" directly, and dynomometers extrapolate horsepower from torque applied.


-Ted

 

im 3rd year.

i dont really consider it an argument, if you look closely, we are all violently agreeing (as funny as it sounds)

between you, me, and the man that could potentially be teaching us all the bs we are spouting right now, we are developing reasoning that Power describes the rate of change in velocity at a given point in time.

Woooo!!!

i dunno about another thread, this thing gets debated so often by people who are waaay smarter than us

 

agreed. The only things that are truly measureable are the fundamental units; distance, mass, time, charge.

Everything else is derived from those units, with either respect to eachother or a constant.

The key is that in deriving things from these measurable units, we are better able to describe certain concepts such as:

Temperature
Force
and how fast a car is

 

yes...i was just thinking maybe i should edit and change it to 'discussion'

to tell ya the truth, i have read up on this subject a lot, because its hard to explain, and i know a hell of a lot of people who will swear up and down that more torque=better acceleration, period. I think some of the stuff from this thread might be able to persuade them better than the arguments ive heard from some of the smart people of which you speak.

pat

 

well, more torque DOES more or less equal better acceleration... its the fact that people DISCOUNT horsepower that is incorrect.

Im going to bed now, nite nite

 

Hello,
I am a newbie here, but not to RX7's. Don't forget time and distance
vary according to how fast you're going (relativity). The only constant
is speed... must go fast, fast, fast!

 

it is a very small variance unless you are going very very close to the speed of light...relativity is an exponential relationship.

pat

 

here we go again...

 

umm i kinda need to know which seals are better i need to rebuild my motor and are the original mazda rebuild kits ne good

 

I certainly hope not...

Not many people are going to argue about how relevant the theory of relativity is to the acceleration of a car..

 

I have 3 comments to make:

1) use the OEM mazda seals, they work, give mazda some credit, they have built lots very sucessful motors using their seal technology (12a, 13b, 24g, RENESIS, etc) Heck, the people have own the La Mans. What more do you want?!


2) all the humbug about hp is stupid. that's all I'm going to say, you're all wrong and fail at life. :-)

3) Ya'll hijacked this thread like a jordan terrorist

 

I've read some amazing things about those stock 2mm seals. I'd stick with those