With suggestion of other I decided to do the math,

250hp @ 2500= 525lb/ft, 3000= 437lb/ft, 3500= 373lb/ft, 4000=328lb/ft

300hp @ 4000= 393lb/ft, 4500= 350lb/ft, 5000= 315lb/ft, 5500=286lb/ft

Which one is producing more power?

And the gear reduction works both ways. As well, if you have to power to move to the next gear, you will increase speed quicker. In regards to not being able to pull past a Acura TL 3.2l, must have had a problem in the engine or trans, and even if the 3.2 stayed with a C4 L98 to 100mph, it will begin to have to produce a lot more power than the Vette to overcome the drag coefficient. Everyone has their theory and I have mine. The choice of power bands depends on application and other factors such as trans ratio's and rear axle ratio's and even tire size. The complete package needs to be considered, not just one factor.

 

You need to consider gear, and time in the gear before judgement.

Maybe I didn't link the right thread -- that talks about it in greater detail. But the gearing trumps the difference in power shown above. Your logic is simply too narrow.

And, there was nothing wrong with my car. You might conclude the 270hp Acura should have won...but there's still the gear ratio to consider. Without checking, the Acura must have been geared at a lower ratio.

 

You didn't finish the math. *Sigh*

.......What you wrote................What you missed....
250hp@2500 = 525tq. Drive shaft speed in 4th gear=2500/3.45 (rear gear) = 724 RPM at the wheels.
^At a wheel speed of 724 RPM with that motor, you're putting down 525 x 3.45 = 1811tq to the wheels.

300hp@4000 = 393tq. Drive shaft speed in 4th gear=4000/3.45 (rear gear) = 1159 RPM at the wheels.
^At a wheel speed of 1159 RPM with this motor, you're putting down 393 x 3.45 = 1355tq to the wheels

WHOA!! What's going on here? What's going on is that you're comparing tq at totally different SPEEDS. Let's get this comparison into the realm of two apples. We'll "down shift" the transmission in the 300 hp engine to a 1.6:1 ratio, second gear 2nd gear now, which will bring our driveshaft speed down to the same 724 RPM as in your 250hp example. Since we down shifted, we get to multiply tq. So, 393tq x 1.6 x 3.45 = 2169tq to the wheels. 2169>1811...no matter what math, dyno or track you use. As you like to say, which one is producing more power? The 300 hp one. That is simplified for you, right in the hp rating!


However, you're right that gears work both ways, so let's do the same comparison, backward:
Lets "gear up" your 250hp "tq monster" to get it's wheel speed to be the same as that of the 300hp example. To get there we need to increase driveshaft speed by ~60%. So we'll accomplish that by shifting into a .624676 overdrive gear, which will bring our drive shaft speed up to 1159, (724/.624676 = 1159 DS RPM) -same as in the 300hp example you used. Since we overdrove the trans we get to divide our tq by the OD ratio, then multiply by the rear gear to get our RW tq: 525 x .624676 x 3.45 = 1131tq to the wheels With our 300hp engine in this comparison, we run 1:1 through the trans, so 393tq x 1 x 3.45 = 1355tq to the rear wheels.
Once again, 1131RWT is < 1355RWT. No matter how you slice it, if you compare the numbers at the same speed (which is the only way to make a comparison), then 300hp engine is able to put MORE TORQUE and MORE HP to the wheels. So...once again, as you like to say, which one is producing more power? 300>250...every day of the week.


Everyone has..."theories", but this isn't a theory. This is something that is mathematically proven. We're way past "theory" when it comes to measuring power. Use the math.

 

Look at this graph; rather than making up hypothetical engines, here are two that showcase the different philosophies that you're talking about: a higher tq, 250 hp engine, and a lower tq, 300 hp engine:



Look at the tq curve. That curve can be interpreted as acceleration G's. The L98 would have an advantage in 1st gear (only), only from about 2400 RPM, to about 3800 RPM. At all other RPM's (gear for gear) the LT1 will be accelerating faster and making "more power". The L98 will shift at about 4800 RPM, (where it'a already making FAR less tq & hp than the LT1), and tq to the rear, will drop even more. Meanwhile, the LT!'s tq is dropping but still higher, and tq to the rear is far higher, due to gearing advantage.

 

Nicely broken down for the guys...It should help make the issue more obvious.

 

In my comparison, I didn't get into calculating drive wheel torque. The question was which rating is producing the most power? I understand your calculations with regard to drive wheel torque, I don't dispute that. But there has to be consideration of what speed(mph) one is considering when deciding to use your downshift method to produce higher drive wheel torque.

 

Flatest lt1 curve I've seen.

 

Or steepest...It really squews the difference in an unrealistic level (compared to road performance.)

 

But when it comes to application, it's rarely about 1 gear. More importantly, it's never about ONLY first gear -- where the 250HP engine stands a chance.

In a race, the longer the 300hp engine has to catch up -- outside the lower range of 1st gear, the more time that 300hp engine has to catch up and win.

In the "real world", I'm fairly certain LT1's win in the 1/8th mile and slaughter in the 1/4 mile. It takes some [simple] mods to make an L98 competitive in the 1/8m...but major ones for the 1/4m. (I think this is relevant considering your choice of engine examples.)

Given your recent post (and video) used to prove an auto-x engine only needs to pull to 4500rpms, I would still suggest a gearing change -- with a higher hp engine (LTx) might work out just as well
as more expensive engine changes.

Do both and you get both advantages....until you get into traction problems of course.

Nothing is ever simple.

Another thing to consider is semantics. HP is a power rating...or a measure of work IIRC. By contrast, torque is a measurement of leverage. "Purists" of the topic would ONLY look at horsepower to answer the question about which engine makes more power.

I'm just sayin'.... (And, mostly I'm saying this because I had to hear about it at one point or another. It's a valid argument. LOL)

 

For my app, usage of the car, the L98 has an advantage in regards to the speeds and the rpms I will be in the majority of the time. I looked hard at the numbers and considered the mini ram. It was probably a couple years ago that I was deciding between the mini ram or long tube intake.

If I were going to run 1/4 mile or 1 mile events, yes I would favor the mini ram (lt1) intake. Or if I ran on tracks that were fast high speed tracks with long straights, I would favor the mini ram.

 

Obviously it would have cost more, but you may be even better with a mini and more gear. So...if you're shifting (or not shifting) at 4500 in auto-x events with your current setup, maybe you'd be launching around cones/turns faster with the MR and more rear-end gear. You'd probably be sitting in a lower gear (even 1st?) for the same event as you pictured. And, maybe you'd require a shift around some cones?

Hopefully, you can see the logic/math being present here.... As much as torque-motor-lovers tout their setup, the evidence supports more power with a higher-rpm intake IN A LOWER GEAR.

For longevity of springs and, really, the engine, you can make a case for the lower rpm motor being the better option. We could also talk about efficiency of the two options since the longtube runs nearer the max VE point of the motor. But, hey, that wasn't even part of that OP's linked "story".


EDIT: I expected to see you running a ZF6, but when looking at your sig, I see otherwise. FWIW, Since an auto shifts so fast, it's hard to imagine anything but better results if you were running more gear and a MR for your events. Easier to hook....more pulling power especially above 28mph (the speed beyond which the higher HP engine [equipped with automatic] has an advantage -- assuming both "hook" equally.) OTOH, 28mph is where the higher HP motor starts gaining. They're not "equal" until a higher speed...maybe 40-50mph? 80mph is closer to 1/8m track times where you see L98's reasonably competing with LT cars. So, it's definitely a complicated issue involving gears, tires, pavement, traction, transmission, and specific application.

And, BTW...since when does a 250hp motor pull 525ft/lbs of TQ? Sounds too high....That's like saying a stock L98 puts out 525ft/lbs of torque. You must have been talking a lower gear than 4th?

 

Well I will admit you guys had me second guessing my decision. So I got home and pulled out my old data I had collected and then looked through the numbers again. I basically used two pieces of data to come up with my decision and that was a speed vs rpm calculator chart that showed speed vs rpm in each gear and at each 500rpm increment from 500 to 6000rpm. Yes an mildly built or stock bottom end can probably spool to 6500 to 6750 before the possiblity of failure. I have my rev limiter set to 6250. So, the speeds I would commonly be falling in would be between 30 and 70mph on a low speed autox and mostly between 60 and 110mph on the road courses I will encounter. Looking at my speed chart I will mainly be running between 3000 and 4500rpm.

Now for the second piece of the data. I read the article and used the data from the article 10 times the torque. I compared the data between the big mouth tpi and the mini ram. The intakes were placed on the same bottom end so it is a fair comparison. Using this data the Big Mouth TPI produced more power from 2000rpm to 5000rpm. After 5000rpm the mini ram begin to produce more with 45lb/ft more at 5500rpm and 40lb/ft more at 6000rpm and that is where the data ends. So, to me it makes sense to go with the Big Mouth, Large Tube Intake. The downshift method doesn't have an advantage here. And to ad to the shifting theory, shifting takes time and creates the possibility of a miss shift. Mine being an automatic with full manual, shifts instantly with no hesitation. It is like a manual without a clutch. But I still shift as little as possible, and shifting mid corner upset chassis balance and can decrease the grip.

Here is the article 10 times the torque-

http://xtremecarzone.com.au/index.php?showtopic=386

 

Thanks! One would certainly think it would have helped...but then you see a post like this...



...and realize that people just don't "Get it".
Dude...question has been answered. It's in the "name"; 300 is greater than (>) 250. I've spelled it out for you with math. I don't know how I can more gently, get the spoon into your mouth. You gotta open your mouth buddy, so that I can spoon-feed you. Maybe if you looked up the definitions of:
*Power
*Force
*Torque
...you might get at least somewhat of a grip on what reality is, here. A 250hp engine makes LESS power than a 300 hp one. There is no way to argue or rationalize around that fact.

 

L98...you are so misguided, it almost hurts to read your drivel.
1. if you're going to make comparisons, try to stay in one place! Geezus. First you make up a mythical engine (obvious that you're attempting to "simulate" and L98 vs. LT1, but fail at that).
2. then you start talking about modified 383's with different intakes. It doesn't matter what motor you're talking about; the one with the higher HP rating...MAKES MORE POWER! Again; open a dictionary. Power, force, Torque -which is rotational force. You'll learn that when you read your dictionary. Now, on to your minutia...
Here is where you FAIL, above.
1. Speed vs. RPM is variable depending on gearing...which can be changed, and also varied from the factory as well, generally to work with the engine. Now if you want to strategize your "build" around your factory rear gear, that is your choice, but it is a very confining way to go about things.
2. So you have an engine that takes a dump at 4500, but ya have a limiter set to 6250?? If you're going to set your limiter there, that WTF would you run a long tube intake??? All your doing over 5k is wasting gas and making noise.




Not in first gear, you're not. NO WAY, you're going 110 in first. In fact, you can't even get to 60 in first. So once you make that shift to 2nd, (before that, actually) you're a loser, compared to the LT1. BTW, I'm at 3450 RPM in 1st gear at 30 MPH. Go back and look at that tq graph and see how big a disadvantage that is (not much), then calc tq to the wheels (what makes the car accelerate) to see who's going to be accelerating faster.



PROVE IT! Show us the math that "the downshift method doesn't work"...You can't because you're dead assed wrong. Not only does it work, but you can also choose a more appropriate rear gear too! LOL.



Shifting does take time. You don't shift from 0-110 -your claimed top track speed, though? Hmmmm



Ooooh..so you have an auto! LOL!! Tracking an auto is like...well, I'll keep that to myself, but why are you worried about "shift times" if you have an auto that "shifts instantly", as you claim? Shifting mid corner (especially with an auto, but not so much w/a well driven stick)) does upset the chassis, but that is the same, LT1 vs. L98. Mini Ram vs. LTR intake. Doesn't matter. Same/same.


You need to learn more about cars, man. Really. And stop posting misinformation in the mean time. Please.
As for "tq vs hp" philosophies, I can't argue about what YOU "like" and/or what you THINK, works best for you. That is a personal decision that you have made and good for you if you are happy with it. But you originally asked, "250hp vs. 300 hp, which makes more power?" The 300 hp engine produces more power. NO WAY AROUND IT. Make no mistake; same car, same driver, a 300 hp car will wipe the *** of a 250 hp car on any track every time. In fact, I invite you to come track with me at Miller. I have a box-stock, 300 hp LT1. Bring a 250hp TPI "tq monster", and then you'll start to see where your *ahem* "theory" has gone awry.

 

Yes I know the def of Pwr, Frc, Trq. No engine makes the same amount of power across the rpm range. Maybe you need to understand torque curves, which obviously you don't. Secondly, maybe you need to work with the hp formula. Then maybe you would not put so much faith in hp. Do you even know the formula to figure HP? I would think not with your assertions.

 

I can tell by your comments, you don't have a clue. So, be as it is, since you don't have any experience on the subject, you should just close your suck. You can bash with your bull5h1t all you want but I have the experience and results to back up my choices. In closing I got 2 numbers for ya- 3825 986.

 

I didn’t want to hijack the OP’s thread, but looks like he is participating, so I’ll re-chime in.

To simplify this debate, we're simply talking about wide open throttle (wot) acceleration I think. And then the question, what works best.... high torque or high HP ?

Rather we like it or not, the answer is and always has been High HP.... its a fact of matter, that when you mush that gas pedal into the carpet, no matter what you do, if you're in the right gear, the engine accelerates immediately up into that final 1600 rpm of engine operation and stays there. And hence, that is the rpm window you want to focus on making the most average HP. It is good to have mid-range torque, because that launches you into that final 1600 rpm and thus assists in your short times (Why the Superram et's so well in my opinion..... it has its meat right where most street/strip cars come off the converter at)

But, then its all motor for the rest of the trip.... a lot of people do not realize it, but if you're doing for example a 0-120 mph acceleration test, you will spend approximately 95-98% of the distance traveled in your final 1600 rpm of operation. (As soon as you floor it your gear and/or converter flash your rpm up and you're at rpm almost immediately) The below video best illustrates this. This is a Z06, but it doesn't matter what it is.... they all work the same, you floor it and the rpm rises lickety split. The video is a fella with a manual transmission doing a low speed roll into high speed. Compare how much time he spends below his final operating range as compared to how much he spends in it. (With an auto and good converter, its even less time spent out of it)


I have no idea how somebody can stay below 4000 or 5000 rpm at wot unless they are in the wrong gear maybe ? I just don't know.... every motor I have ever had, when press the go pedal, rpm rockets up and I couldn't stop it even if I tried. Its even more pronounced with an auto with the right converter.

I could talk more on this subject, but I'm already rambling on, so I'll stop... but its a good and fun discussion to have.

 

It seems you still don't get how torque multiplication works when figuring power at the wheels. Your "The downshift method doesn't have an advantage" comment makes zero sense.

I tried to explain how the lowest speeds are the only place where lower-rpm power [TORQUE] has an advantage -- if you can make it hook. You're throwing that out the window by stating average speeds 30mph and up.

All you have to do to realize more gear with more rpm would help you out is to look at 1/8m and 1/4m race data. You haven't done that. First thing you'll find is long-runner intakes aren't winning. BIG-AZZ versions like the FIRST can come really close to keeping up because their extra flow helps with the top-end...so driver's can stay in a lower gear longer. But, it's the minirams and superrams that are winning races these straight-line races. In auto-x events, the only guys competing with long-runner intakes -- are running in classes that are limited by HP. You are correct in concluding more torque -- with the same top-end HP -- wins that race. Again, that has to do with acceleration from a stop. More torque gets you there faster. But, that only works when top-end HP is held constant and gearing isn't brought into the equation....

There is some leeway [grey area] on the torque vs traction issue otherwise, the minirams would always win 1/4m races. That's why I said it was a complicated issue. But running races in the 30-110mph range dictates the need for higher rpm than you're specifying. The fact you have an automatic demands it.

I had similar thoughts reading articles like "10-Times the Torque" when building my engine. The difference is I simply considered how often I wanted to jump down 2 gears -- with a ZF -- and crank the rpms. I don't run races. I only drive mine on the street. I only cared about longevity and torque in the 1500-4500 rpm range because of my driving style. Most importantly, I decided I won't be double-downshifting very often. With enough torque, it's not necessary. (I'll be honest, down or upshifting a stick two gears at a time, just isn't a ton of fun. Single-shifts are what the pattern is most "geared" to do. (See how I made some word-play there! LOL)

You can be certain if I was racing, I'd be in a lower gear and building an engine that ran up to 6500rpm minimum. That's because "the downshift method" works. If you really look at gearing and what a lower gear gets you, it's close to double the torque. Running in a lower gear doubles your leverage at the wheels. I'm not going to say power, because that's a misnomer. If you look at your 10 Times the Torque article, the difference -- even where a long-tube intake generates more torque than a shorter one -- is not as much as gearing gets you. Torque gains -- in lower rpms -- are only on the order of 10%. Torque gains from downshifts are considerably more.

Downshifting does make a difference.

 

If I were running in a straight line, trying to accelerate as quick as possible, I would go with the mini ram myself, but I don't. My application involves varying speeds all the time; slowing down and then back on the throttle all the time and like I stated before, with my ratio in the rear and gear ratio's in the trans, I am usually fluctuating between 3000 and 4500rpm. If I did downshift to take advantage of drive wheel torque I would only have and advantage for a about 3 to 5mph and would have to up shift and that would make me fall below the rpm that was an advantage and then I have to slow down and downshift again.

And once again I will say that I would choose the mini ram for straight line acceleration and yes I get what Gregg is saying about utilizing final drive wheel torque through torque multiplication in a lower gear and on some tracks out there that are higher speed tracks, his method is best.

 

First, If you knew the definition of POWER, you wouldn't have asked the stupid question "which has more POWER; a 250 hp engine or a 300 hp engine". But ya did.

Secondly, I am abundantly aware of what a tq curve is. My math above (had you READ IT [and comprehended it]), would have made that clear to you. Reading comprehensions 101. Check it out while you have your dictionary open.


Again. READ MY POSTS above. It is abundantly obvious that I know how to calculate hp from tq and RPM, and tq from hp and rpm...did you even READ my posts?? Please. Open your mouth, as that will make it much easier for me to spoon-feed you.