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What is it that makes it so hard to get big hp numbers?

Old Aug 1, 2008 | 01:31 PM
  #26  
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Originally Posted by rotary.enthusiast
The renesis doesn't produce amazing torque at the crank, no, but it's torque curve is incredibly flat compared to most piston engines, and it revs higher as well. It's not quite the "electric motor" delivery Mazda makes it out to be, but it's damn good for an internal combustion engine. A 300 HP renesis (barring laggy turbo setups) will have more area under the torque curve than any other engine that produces a similar peak HP number. Then you just use proper gear ratios in your trans/diff to put the torque to the ground that you desire.

Peak HP is just a theoretical measure of the top speed of a given vehicle... it doesn't tell you how fast that car will get to that speed. It's pretty meaningless by itself... area under the torque curve (or HP curve if you prefer) is what matters.
Thanks, that explains a lot. I understood the high revving part, but I didn't quite understand before the area under the torque curve. I'm defnitely one of those people that I couldn't care less what my top speed is (because lets be honest, N/A Rx8 has a top speed most of us will never hit) but I'm definitely concerned in how fast I get there.
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Old Aug 1, 2008 | 02:14 PM
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Well, once you're moving, the only real part of the torque curve that matters on an rx8 is above 6k. The redline on the MT is high enough that you never need to drive below 6k. I mean, it's nice in some turbo cars to just drop your foot in top gear and have a nice amount of acceleration, but it isn't entirely necessary. An evo isn't going to go to a track day and just do laps in 5th. Torque curve shapes are important in different ways depending on what you do. A track car wants high torque through whatever rpm band is in use. A drag car wants as much torque following the shift as it can get. Acceleration early in a gear is faster than acceleration later. You could make a case that by tuning a drag car for minimal HP (delining torque curve) is faster than maximum hp (increasing torque curve).

Then again, more torque at all RPMs is pretty sweet too.
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Old Aug 1, 2008 | 02:25 PM
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This is probably the most nicest thread I've ever read on here. With a lot of basic knowledge for all. I'm impressed with the politeness.
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Old Aug 1, 2008 | 02:28 PM
  #29  
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Which of these cars is faster from traffic light to traffic light?

Attached Thumbnails What is it that makes it so hard to get big hp numbers?-tq_tq.jpg  
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Old Aug 1, 2008 | 02:35 PM
  #30  
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Originally Posted by maxxdamigz
Well, once you're moving, the only real part of the torque curve that matters on an rx8 is above 6k. The redline on the MT is high enough that you never need to drive below 6k. I mean, it's nice in some turbo cars to just drop your foot in top gear and have a nice amount of acceleration, but it isn't entirely necessary. An evo isn't going to go to a track day and just do laps in 5th. Torque curve shapes are important in different ways depending on what you do. A track car wants high torque through whatever rpm band is in use. A drag car wants as much torque following the shift as it can get. Acceleration early in a gear is faster than acceleration later. You could make a case that by tuning a drag car for minimal HP (delining torque curve) is faster than maximum hp (increasing torque curve).

Then again, more torque at all RPMs is pretty sweet too.
YES!

Do enough driving at fast tracks like Road America and you'll gladly give up power from 3-5.5 K in exchange for more headroom from 5.5K+.
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Old Aug 1, 2008 | 02:41 PM
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Nevermind. My small brain has comprehended it!

How far apart are the traffic lights? And why are you street racing? You're a bad man!

Last edited by maxxdamigz; Aug 1, 2008 at 02:45 PM.
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Old Aug 1, 2008 | 03:18 PM
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Originally Posted by maxxdamigz
Well, once you're moving, the only real part of the torque curve that matters on an rx8 is above 6k. The redline on the MT is high enough that you never need to drive below 6k.
Fair enough. The way the 8 is geared if you redline it you're not going to be using a lot of that area under the curve after you get out of 1st gear... it's still nice to have for driveability purposes. Personally I'd like to see a reworked gear-box for NA 8s... the '09 ratios are probably a step in the right direction, but it would be fun to play with something even more aggressive. I'd need to sit down and work out the ratios, but I think it could be made a fair bit quicker than it is right now with the downside being it would be harder to drive, and 1st gear would be totally useless at anything other than a dead stand still
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Old Aug 1, 2008 | 04:59 PM
  #33  
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Originally Posted by quazmosis
This is probably the most nicest thread I've ever read on here. With a lot of basic knowledge for all. I'm impressed with the politeness.
Me too, I seriously appreciate not being flamed to hell and actually learning something.

RE: MazdaManiac, I think I see what you mean showing the dyno, the high end of the hp/torque might be higher on the purple car, but the yellow car has a much flatter torque curve?
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Old Aug 1, 2008 | 05:03 PM
  #34  
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From: Under my car
Think in terms of how much shaded area is under each of the torque curves.
The car with more shading is going to be the faster car.
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Old Aug 1, 2008 | 05:15 PM
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Originally Posted by MazdaManiac
Which of these cars is faster from traffic light to traffic light?


I don't know. How much does each of them weigh? Who's driving them and how are they geared. Tires count too.
10,000+ posts? What else do you do?
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Old Aug 1, 2008 | 05:18 PM
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Originally Posted by Richard Paul
I don't know. How much does each of them weigh? Who's driving them and how are they geared. Tires count too.
10,000+ posts? What else do you do?
lol.

The are both 2004 RX-8s. You can deduce the rest.

I spend a LOT of time in airports right now, so what else am I going to do but post on this forum?
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Old Aug 1, 2008 | 05:52 PM
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Originally Posted by MazdaManiac
Think in terms of how much shaded area is under each of the torque curves.
The car with more shading is going to be the faster car.
Hmmm - I'm pretty sure I could come up with a torque curve scenario where a car with a lower torque curve area would still win (albeit still favoring lower end torque). Then again, if I needed a car that would blow everyone's doors off from a dig, I probably would not have bought the eight. I loves me some top end.

When you swinging out east, MM?
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Old Aug 1, 2008 | 06:07 PM
  #38  
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Originally Posted by maxxdamigz
When you swinging out east, MM?
I'm in MD almost every week, but there isn't any time for car stuff, unfortunately.
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Old Aug 1, 2008 | 06:17 PM
  #39  
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MD - semi too far south unless you're in MD on the weekend of 9/7. That looks to be the JPR BBQ which is not terribly far from MD.
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Old Aug 1, 2008 | 07:27 PM
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Good info. So what is the desirable torque curve to have the best acceleration from 0-100 mph? How would you calculate getting the correct gear ratios to achieve the best torque to the ground for that?
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Old Aug 1, 2008 | 07:29 PM
  #41  
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Originally Posted by MazdaManiac
No, I don't.
Saying you have "X" amount of power is meaningless. It isn't another level, its just nut-swinging.

If you have two cars - exactly the same in every way and both making 300 ft/lbs of torque - but one makes 500 HP and a torque curve shaped like "^" and the other makes 300 HP, but has a torque curve shaped like "¯", which is the faster car?

I will take a car with half the power but twice the area under the torque curve any day of the week in any form of racing - even bracket drag racing.
i dont mean making more power to say you have X amount of power and bragging about it. What im trying to say that some people decide to make there car faster to experience to what limit there car/engine will go to understand. not all of us buy a car just to make it faster, we enjoy the car as much as we can until we get curious about its limits then we start modifying it bit by bit.

Also in the long run the car with a the torque curve shaped like "¯" will with out a dought win but if its just a 1/4 mile i'll take the car with the torque curved shaped like "^", it's just a 1/4 mile most drag cars only go up to 4gear. thats just how i look at it....

Last edited by Rotore_787; Aug 1, 2008 at 07:36 PM.
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Old Aug 1, 2008 | 08:08 PM
  #42  
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Originally Posted by blackenedwings
Exactly Rotore, it's not just the raw power, its that I would really like to invest some time and money into my car and make it something special, but I see a lot of modded Rx8s that don't seem to get a lot of notice or attention in the tuner scene because they have low hp numbers. I mean, I don't give a rats *** what people think if I like it, but I do like torque/hp and was curious what was keeping 8s from showing higher numbers.

I would love to have a 20B swap because I think the 3 rotor engine is the best sounding engine I've ever heard... I mean, it sounds like it's trying to eat someone. *drool* That being said, I don't think that a 20B swap is doable for me atm just due to price of the swap. I would never go LSx with an Rx8 anyway, because I've had a Corvette and although it's a great engine it loses the characteristics of what an Rx8 is about to me.
RX-8's don't get a lot of attention in the "tuner scene" because most people are ignorant and don't know squat about them. They hear rumors about different things like reliability, eats oil, low end power and automatically assume they suck when they don't know any facts about it.
Even in an N/A 8, just keep the revs high and it will put a smile on your face every time. Especially when getting it sideways around turns...

I agree with everyone on the HP doesn't mean anything, its about the torque and the curve it produces. Alot of people I work with ask me how much HP I will get after I get the MM/BHR turbo kit. I tell them I'm looking for about 300 at the wheels and they seem disappointed. I try to explain the torque curve to them but they don't get it. People get so stuck in HP numbers and they think that's the only thing that matters. Very annoying. If they drove the car with the kind of numbers MM was putting down, I'm sure they would change their minds. That's fine though, I will have fun in my car and the ignorant people can just go buy their muscle cars and can be unhappy. At least they will have 298342946198247useless RWHP that can only go in a straight line along with the useless "bragging rights" to go along with it. Boo.

--Jonathan
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Old Aug 1, 2008 | 08:24 PM
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Originally Posted by 05rex8
RX-8's don't get a lot of attention in the "tuner scene" because most people are ignorant and don't know squat about them. They hear rumors about different things like reliability, eats oil, low end power and automatically assume they suck when they don't know any facts about it.
Even in an N/A 8, just keep the revs high and it will put a smile on your face every time. Especially when getting it sideways around turns...

I agree with everyone on the HP doesn't mean anything, its about the torque and the curve it produces. Alot of people I work with ask me how much HP I will get after I get the MM/BHR turbo kit. I tell them I'm looking for about 300 at the wheels and they seem disappointed. I try to explain the torque curve to them but they don't get it. People get so stuck in HP numbers and they think that's the only thing that matters. Very annoying. If they drove the car with the kind of numbers MM was putting down, I'm sure they would change their minds. That's fine though, I will have fun in my car and the ignorant people can just go buy their muscle cars and can be unhappy. At least they will have 298342946198247useless RWHP that can only go in a straight line along with the useless "bragging rights" to go along with it. Boo.

--Jonathan
Boo? but i rather have both hp and tq
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Old Aug 1, 2008 | 08:24 PM
  #44  
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the Mazsport will wtf rape your's MM, it's simple math really, 8.5K wins over 6.5k........ seriously....I thought you were smart
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Old Aug 1, 2008 | 08:28 PM
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Originally Posted by Rotore_787
Boo? but i rather have both hp and tq
That's a given. I wasn't talking about having alot of both though. Was referring to how people seem to only care what HP I have in the car, not what the torque curve is or how much.

--Jonathan
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Old Aug 1, 2008 | 08:37 PM
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Originally Posted by 05rex8
That's a given. I wasn't talking about having alot of both though. Was referring to how people seem to only care what HP I have in the car, not what the torque curve is or how much.

--Jonathan
they dont know better... you have to let them learn the hard way
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Old Aug 1, 2008 | 08:40 PM
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^agreed
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Old Aug 1, 2008 | 08:48 PM
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thank you and nice car
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Old Aug 1, 2008 | 09:40 PM
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Originally Posted by MazdaManiac
Everyone that wants a 500 HP+, <3.0 liter car has never driven one on a daily basis.
That was my point up until 6:00 or so yesterday.
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Old Aug 1, 2008 | 10:13 PM
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You are out in MD every week MM? What area? I live down the street from BWI pretty much.
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