OdessitPashka

iTrader: (8)

To those that said that power under the curve doesn't mean **** from a roll watch this video: http://video.ls1tech.com/video/98c3d...1d00052b02.htm

C5 FRC with 473whp VS Fadi's stock Z06 with 460whp. Both weigh the same, but Z06 RUNS AWAY with a passenger!!! Guess why... the mighty power of 427ci VS 347... Torque curve of the 427 makes a huge difference!!!

OdessitPashka

iTrader: (8)

Here is a dyno sheet of this particular 350z:



He has 200whp increase that lasts a second... and his torque curve looks like an ice cream cone. Compare that to the flat 420tq of the vette basically from 4000 to 7000rpm and now tell me why 350z lost...

300bhp/ton

Well I think this is another case of these so called high HP turbo motors not really running the numbers they claim. Sure on a DYNOJET dyno running 100 octane fuel, no graph smoothing and STD correcting they may well be able to make 500+rwhp. Slap that same car on the street on 91/93 octane and it's probably a 100 or so rwhp less in real life. Hence the *** kicking.

Sorry but that's PEAK numbers are precisly that PEAK meaning at a set rpm. To run thru a gear you have to start lower in the rpm band, hence using the under the curver performance.

If it had a CVT (constant velocity transmissoin) then under the curve would mean jack ****, as you could keep the engine at a set rpm (PEAK HP) and constantly alter the gearing to accelarate. But as this 350z had convention gears under the curve is very important.

And anyhow who really give a toss anyway. That 350z could be making 1500hp for all I care. The Corvette still looks and sounds way better along with having a much better image, more sex appeal and better desireabilty.

LSINA7

iTrader: (8)

You're right, both cars might not be in their perfect power band, but...

Exactly. I have been driving turbo cars since before I had a license, and the first thing I was taught was how to brake boost. This is an amazing thing, because you can be in the wrong gear and still take off hard as ****.

I'm not calling B.S. on the race, or taking up for the 350. I don't even like 350's. But, something had to be wrong with that driver if that car made 520 whp.

LSINA7

iTrader: (8)

Dude I agree with everything you wrote. I'd 50 times rather have the Z06. But read what I wrote. Its not hard ot keep a turbo car in it's powerband.

300bhp/ton

I was only speaking with reference to your comment about under the curve. Keeping a car in its powerband is one thinig but thats still using under the curve. Gearing and setup are vital. But on a highly tuned turbo setup you may have a very narrow powerband, which means keeping it in it is almost impossible.

I've only really driven one extreme example, but I know it happens a lot. Basically if you shifted at the red line it would drop you too low in the rpms and bog down big time. So the only answer was to over rev the engine at the high end, but by doing this you where not only running the risk blowing it up you where also way past PEAK and the power had dropped off. There really was no answer, it was just a pig to drive. But having owen several turbo vehicles its quite easy to see how it happens and shifting even a couple hundred rpm early means its off the boil in the next gear.

Fadi

Fadi

What can I say man, I LOVE racing..

Fadi

Let me explain something, and just a thought.

A lot of people talk about area under the curve, and how important it is. Yes, this is true and I agree, but, What about everything else that should be taken into consideration?

When I raced Doug, aka "allngn_c5" in his 473 rwhp C5, I was not making more rwhp than him under the curve at any rpm, yet, I was able to pull away every time. Why?

How about an SRT-10 Viper? I had an SRT-10 and let me tell you, by looking at both the dyno sheets for the Viper and now the Z06, the Viper made more rwhp at any rpm below 5500, and it was only then and beyond that the Z06 made more rwhp, yet, I would walk away from a Viper. The Viper also made a hell of a lot more rwtq at any given rpm. So, what am I trying to say?

While area under the curve is important, it does not tell the entire stroy imo. Gearing, rpm, weight, aerodynamics, and power delivery are all characteristics that must also be factored in, and, imo, this is where the Z06 dominates making it victorious in a lot of these races.

The 350Z did pull me once when I was in 3rd @ 70 mph while having a passenger. He did not have a passenger and was in his powerband while I was not. So, being in your powerband will help, of course, but, I was reeling him in and was ready to pass once my rpms started climbing.. The Z06 was just the faster car, despite the difference in the power both cars made.

unit213

Doug's graph of the 473rwhp is STD. I would imagine SAE numbers are
more along the lines of 455-460rwhp, which is just a few more ponies
than you have. With your weight advantage, it's clear why you were
able to pull every time.

LSINA7

iTrader: (8)

+1. I completely agree on this post.

COMNBYU

I think some of you are missing the fact that the hp/tq curve and "being in your powerband" are intertwined.

Let's just say, that the they started the race at 60mph. The 350Z in 2nd gear in the Z06 in 3rd. If the 350 was around 4,5k rpm or so (going by the graph) then that should be a good starting point. The Z06, while not at it's prime starting point, would still pull pretty good because of the flat curve of power.

So, having the one helps the other. Yes, you need to be in your powerband to run 100%, but having a flat curve makes it easier to do that.

If you had a car (in theory) that made 600hp/tq from 2k-7k rpm then you could start a 45mph race in 3rd or 4th gear and it would run just as fast as if it was in 1st or 2nd.


I know this isn't anything new or rocket science, I just felt it needed to be reiterated for the people that were saying that the curve doesn't matter and that the he wasn't in his powerband.

300bhp/ton

Agree with you post except this bit. As HP is an expression of torque at speed, i.e.

HP = torque x rpm / 5252

You can not keep equal numbers over an rpm range.

Example (using the above equation):

600lb ft x 2000rpm / 5252 = 229HP

But the same torque at higher revs:

600lb ft x 7000rpm / 5252 = 800HP

This is why high revving DOHC 4 & 6 cylinder engines can make BIG bhp but low lb ft torque.

A small amount of torque at high rpms will often yield more HP than lots of torque at low rpms.

But the as proven by this vid, having the highest HP doesn't mean it's the most powerful or the fastest setup, because there are so many factors involved.

COMNBYU

Yes I know, that's why the (in theory) was added in there I was just trying to make a point.

However, it is possible to get close results that won't vary as much. There was a Vette that was posted over at SVT.com with a KB I believe that made some amazing numbers (hp & tq) at around 2k rpm. And it only went up in power a little to redline.

In reality, if you have a car that made 500hp/tq at 2k rpm and peaked at 600hp/tq at say 6k rpm, then my point I was trying to make really proves itself in a real world situation. You could run almost as fast in a 45mph race in 4th gear as you could in 2nd.

I understand that you can't have a completely flat curve in the real world though.

98SS1LWEE

iTrader: (25)

Wow, did you guys break 60, you passed the minivan and it looked like it might have been hanging with you if it hit it, ha ha, nice cars

LSINA7

iTrader: (8)

I saw that KB car. If 2 cars raced off idle, that 800 whp Vette, and a 1000 hp turbo car. The Vette would destory it out of the whole. But since the turbo car could begin in its RPM range, it could pull the vette out of the whole, even though it the vette makes way more power the the whole band.

Are we saying the same things?

LSINA7

iTrader: (8)

Yep... But I feel people don't see this, and they think since a V8 makes it power quicker in the RPM range, that it will automatically be faster. Just like the 12 second 800 hp Supra comments. People don't understand you don't have to race off freaking idle.

LSINA7

iTrader: (8)

Just like this post. I have never understood what the bold matters? If you always are above 3,000 RPMS in a race, why does it matter if you only make 150 whp there? Its says the 350 needs to be wound. Ok. If you brake boost the car, it is wound out. So why would it fall behind?

300bhp/ton

It may have had a flat tq curve but HP would rise accross the rpm range until eak and then dip. Don't let the visual graphs put you off sometimes they use strange grading systems so the visual representation doesn't tally with the real affect.

The only way to have a flat HP curve would be to have diminshing torque as rpms rise.

I think I get what you are saying, but your numbers are all wrong. You simply CAN NOT have 600hp and torque at 6000rpm, because:

600lb ft x 6000rpm / 5252 = 686HP whether you want it or not.

And again you can not physically have 500lb ft and 500hp at 2000rpm.

500lb ft x 2000 / 5252 = only 190HP

To make 500HP @ 2000rpm you'd need in the region of 1500lb ft @ 2000rpm.

HP increase is not linier to torque increase over an rpm range.


Well that's not exactly true, accelaration in a wheel driven car also relies on gearing and traction. But even removing them from the equation your theory still doesn't stand up.

1. Because neither car would be lunching at PEAK power. But both would be launching high in the rpms.

2. Even if they could lunch at PEAK power in terms of rpm, the turbo motor wouldn't me making PEAK HP becuase there's no way to build full boost without sufficent load.

So there's a very real possibility the less PEAK powerful car may make more power for 85-90% of the time/powerband.

Again this is why Supra's and the like require such high HP to run comparitively poor times. It usually has nothing to do with traction but looking at the 1/4 run as a time section they will probably only be making PEAK power for a very small percentage of time. Where as a car with less PEAK but a broader powerband will probably be making more power for most of the time.

Hence 700rwhp V8's will run faster (better ET's) than 1000rwhp Supra's.

And don't think I'm bashing, becuase I'm not. I'm from GB and small engines rule pretty much all the time. But there's no denying physics.

COMNBYU

Yes and no.

Of course a car with more hp will outrun a car with less. You're comparing a 800 hp car to one with 1000 in your above senario.

Now, lets take a more realworld example. A stock C6 Z06 with lets say 450whp versus a BPU++++++++++++++ (sorry, I had to ) Supra with 450whp. Let's also assume for the time being that they weigh the same, Supra has weight reduction or the Z06 has a boombox the size of a small shed, whatever.

We all know what the curve looks like on the 427. The Supra probably wouldn't starting making good hp until around 4k rpm or so.

In a dragrace, yes it's possible for the Supra to run with the Z assuming everthing's right with the world and the planets align at the same time. Can it be done? Yes. Does it make it harder? Sure it does. The Supra doesn't have power all over, just in a small spot. So you've got to be right in that spot to run 110%.

Now, in a real world race on the interestate or the like, it's a little different. The Supra is more than likely not going to come across someone in a C6 Z06 who says "Ok man, what mph do you want me to get to so you can be in your powerband." More than likely you'd line up somewhere between 45-65mph and just go at it. And if The Supra's not in the right gear or at the right rpm he's gonna get hurt.

Now before you start talking about "brake boosting" let me say this. If we take the two aforementioned hypothetical cars and line them up at 45mph in 4th gear and let them have at it what do you think the outcome would be? The Supra coud be brake boosted to its hearts content and it's not going to matter. One thing I don't think you understand is, brake boosting isn't the same as having a two-step at the tree in a dragrace. In a run from a roll if the Supra's in the wrong gear "brake boosting" isn't going to make up for the fact that the power curve is what it is. It can help the car leave a little better with more response but that's it. Lets say the Supra in mention's turbo is limited to around 20psi max. If it makes 450whp at 20psi @ 6,5k rpm and 200whp at 20psi @ 3k rpm, then it doesn't matter how much you brake boost, it's still only going to make 200whp at 3k rpm.


Hope that all makes sense.