SRT-10 down on torque?

GTS Bruce

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Looking at the projected torque #'s which are at a much higher rpm makes sense when you look at the short intake runners.It is my guess that the srt-10 will not match the low end torque of a gen-2 viper. Bruce
 

Vic

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Bruce, I think you are right about the rpm. Probably, it wouldn't even have Gen 2 torque levels, with those shorter runners, unless it also had a bigger displacement. The shorter runners extend the torque to a higher rpm level, (because they offer less restriction to the incoming air flow than longer runners) thus resulting in an increased horsepower figure over the same engine with longer runners, like the Gen 1+2 intakes, all other things being equal. But those shorter runners reduce the twisting force at lower rpms, since they have no inertia effect.

Horsepower figures are a mathematically arrived at derivative of torque and rpm in a formula, which escapes me right now. Its all about torque, and the higher the rpm that you can keep up the twisting force of the engine, the higher resulting HP number. HP is really torque, as a function of rpm.

Short runners basically just get out of the way of the air flow, where longer runners give the air a place to rush into and pile up, generating the inertia compression. Too short of a runner offers no inertia effect, except at higher rpms. Too long of a runner may generate both compressions AND rarefractions in waves, netting no useable inrush inertia compression gain, and which may not coincide with intake valve opening, and generating CFM flow robbing turbulance. The tuning of the length of the runner varies from like 17.5" inches on an L98 small block Chevy, (low rpm advantage), to what, like 6" on a trumpet intake like you used to see poking through the hood, on race cars of the 60's? (Netting inertia compression at higher rpms, with minimal restriction).

Ideally, the intake runner length should be infinitely variable through all rpms, with some kind of variable intake runner tube, or some such system. The ZR1 had two butterflies, opening first small runners for low rpms, and then as you mashed the pedal, the second runners opened, allowing greater flow. An ineteresting answer to the runner dilema. If you had infintely variable, rpm sensitive intake length, and added to that variable valve timing, and intake valve throttling, you would not need huge displacement to get the torque and HP of our V10s. Displacement is just the cheapest way to get performance, but in no way represents any pinacle of engineering. Gasoline is more powerful than TNT, in the right proportion with air, and much of the energy of the gas is merely wasted, in current engine technology.

So if you are intent on publishing higher HP figures for your new model, you can fairly easily cast a shorter runner intake, which gives a tuned runner length advantage at higher rpms, and an attractive cosmetic difference from last years' model, generating endless disscussions and "buzz" effect. And to avoid the loss of low rpm torque that those short runners will cause (due to the lack of enough length to generate inertia compression of inlet air at low rpms) , they have to give it more displacement for compensation, which increases low end torque by virtue of the sheer amount of combustion taking place.

If there was a 200 cubic inch engine that made as much torque and HP as your Viper, took up less space, weighed less, made less waste heat, used less gas, would you like it? I'm not sure I would, because I am so conditioned to appreciate huge V8s, and obviously, the V10 Viper.

One argument for currently available mass-produced engine technology is, that metal bearing surfaces last longer in a larger engine, and the large bearings in the engine withstand heat better, than do small engines that rev high, and have high HP numbers. Is this a good argument? I don't know what to say to defend current technology. Uhm, lets see, Its cheap, and simpler to fix, easier to repair than a high tech engine.

There, how did I do?

I know that you already know this stuff, and hope you will excuse me for being gabby.
 

Steve Ferguson

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I can't divulge where and when this happened, but I can tell you that I have seen (with my own two eyes) a SRT/10 lined up against a GTS, and the result was staggering. I don't know why there was such a big difference from the get go, but there are going to be a lot of ultimate speed freaks who will either have to modify, or move up.
 

Mike Brunton

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Maxwedge:
Hp is a theoretical number. Torque (and the curve that represents it) are real and are the variable that someone should look at. HP is a number for marketing and Turbo cars.
<HR></BLOCKQUOTE>

With all due respect, you couldn't be further from the truth. Some folk say "torque is what gets you down the track", others say "torque gets you moving, HP keeps you going". It's wrong on both counts - you CAN'T make big TQ without making HP, and vice versa. A mack truck makes a ton of torque, but very little horsepower - how would that motor feel in a Viper?

Alot of cars have plenty of low-end kick - like the GenI Viper, the L98 Corvette, etc, etc. The manufacturers usually move the TQ curve up a bit without sacrificing low end, and they gain a bunch of HP. A big TQ motor without alot of HP will feel like a monster down low, but will run out of breath - like the L98. A big HP motor with low TQ (a revver) will feel gutless at low RPM, but will scream up top.

I want both. I'd be surprised if the SRT loses any torque to a GTS anywhere in the RPM range.
 

Vic

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Mike, talk about screamers at high rpms-

My son's 99 Cobra revs like a dream, and sounds like a full on race car. But every time I get in it, I stall it out, cause its got like "0" torque down low. But for a naturally aspirated mouse motor, (4.6L), it really hauls after it gets going. Much better than my L98 Vette did, with 5.7L.

Torque is twisting force, regardless of what rpm you are talking about. This twisting force launches the car off the line, and fights wind resistance at higher speeds/rpms. If you have enough gears, you COULD get by with a diesel motor that makes all its twist in a narrow band, like 2000-3000 rpm. But you would need like 13 gears to keep the engine in its power band, as the vehicle speed increases. Since this is utterly ridiculous and impractical, we need engines that have enough low end to launch, and also maintain their twist at higher rpms. The better the engine is at doing this, reduces the need for shifting. Ideally, we would like to scoot down the 1/4 mile with as few shifts as possible. If a hypothetical engine had thousands of pounds of torque at idle, and maintained this boatload of torque all the way to 30,000 rpm, you would not need a transmission at all. Since piston engines don't have these characteristics, we must shift, which wastes time, and causes a momentary reduction in acceleration rate.

Trying to get an internal combustion engine to do just this is the art of the tuner, the challenge of the engineer, and the endless pursuit of gear heads since day one.

Interestingly, electric motors start at zero rpm already at their maximum rated torque, and in the case of an AC induction motor, they can be infinitely varied in rpm, using a variable frequency
drive, all the way up to the maximum rpm at which the rotor starts to disintegrate. The GM Impact has no transmission, and does no mechanical shifting at all, but rather increases the frequency of the 3 phase power to the motor windings in a smooth, stepless rate, from zero rpm, up to something like 20,000 rpm. It does have gear reduction, but this ratio never changes, and only serves to allow a small electric motor to haul a metric ton of batteries. If battery technology inproves in our lifetime, you may see electric cars handing internal combustion engines their lunch.

[shudder]
 

CAP

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Vic Rough:
There, how did I do?
<HR></BLOCKQUOTE>


I'm impressed.
yesnod.gif
Never really knew or thought about all that runner stuff, but it makes sense.

Electric cars =
puke.gif
 

Mike Brunton

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Vic,

I hear ya bud
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. I guess when it comes right down to it, you never feel horsepower at all - torque is the ONLY force that accelerates a car. Horsepower is a good way to tell how a car's torque curve looks though - if a car makes 300lb-ft but 900hp, it must be a revver... if it makes 700lb-ft but only 300hp, it's a torque motor down low but with no RPM's.

The diesel example you cited is flawed in that every time you shift into another gear, the torque put to your wheels drops dramatically, slowing you down a whole bunch. I'd love to race a 1,500lb-ft diesel motor in my 490lb-ft Viper.

P.S. Vic, don't you just LOVE the DOHC motor in that Cobra? I sometimes miss the torque, but the revving ability of that sucker is amazing.

P.P.S. If I could give you an Indy car motor for your Viper that made 350lb-ft, but revved to 18,000RPM and made over 1,000hp, would you be interested? Heck, you'd cross the 1/4 mile mark in 1st gear!
 

Vic

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Hey, Mike...

Yeah, I know a slow turning diesel won't win any races with a triple "H" pattern.....

When I said you COULD get by with a diesel, I unintentionally threw my reader off the point I was trying to make.

What I was driving at is the relationship between torque, HP, and shifting. If you have a boatload of torque, it is useable without a high horsepwer rating, if you have enough gears to maximize the engines' potential. To understand some subjects, it is helpful to draw extremes in analogies, to help the unitiated grasp the basics of the issue in a fundemental way.

I like how you put it:

"I guess when it comes right down to it, you never feel horsepower at all - torque is the ONLY force that accelerates a car. Horsepower is a good way to tell how a car's torque curve looks though - if a car makes 300lb-ft but 900hp, it must be a revver... if it makes 700lb-ft but only 300hp, it's a torque motor down low but with no RPM's."

Well said. Most piston engines' torque drops way off at higher rpms, due to the difficulty of getting the charge in and out of the cylinder, as the CFM increases through the engine. Through the last 50 years or so, engine air filters, air intakes, head, valve, and piston design, ignition, exhaust design, has been undergoing a slow but steady improvement process (even considering the switch from 60s gross dyno HP figures, to modern "net" dyno HP, and breifly taking a sickening detour in the 70s with the carburated "smog dogs") As the technology improved, torque was maintained at an ever increasing rpm.

So, what we can conclude from this?

Torque is the essence of the issue, but HP is still a useful figure, worthy of reporting, because it indicates how efficiently an engine gets the charge into, and out of, the cylinder. Its sort of a barometer of an engine's sophistication.

And yes, I love that high revvin' Cobra, (once I get it going), but not as much as I love my Viper. Our V10s have so much torque, (as well as HP), that you can plow the North 40, and then turn low 12s in the 1/4, too. Now if they would make it 72 degrees, we could get that F1 whine!

If you could give me an Indy car engine for my Viper that screams like that, I'd put 3:73s in to launch it without stalling, and a parachute to bring it back down to earth at the end of the strip!
 

Vic

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Thanks for noticing, Craig!
Say, can you tell me what you use on your rims?When you pulled into Krispy Kremes, your wheels had more shine on them than anybody else's. What did you use on them? Lotsa "bling-bling"!
 

Mike Brunton

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Vic,

I agree completely... the only thing I would say (again) is that the torque put to the wheels is what moves you. It's great if an engine makes 500lb-ft, but if it can only rev to 3,000 RPM, and another car makes 400lb-ft, but holds that power up to 7,000RPM, you can gear the lower torque motor lower... at 30mph, the first motor might be in 2nd gear, whereas the latter might be in first... if the torque multiplication is 3.00 in 1st vs. 2.00 in 2nd (pulling numbers from air), the less powerful motor is going to pull that 500lb-ft motor and it's gonna pull it hard.

But I'm just nitpicking - I know what you're saying and I agree completely... but I love motors that can rev and have alot of torque. The GTS's big improvement over the GenI Viper was where it made it's power - it doesn't really make more torque, it just makes it higher up without losing it down low... which adds tremendously to the grin-factor, as you would know
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CAP

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Vic Rough:
Say, can you tell me what you use on your rims?When you pulled into Krispy Kremes, your wheels had more shine on them than anybody else's. What did you use on them? Lotsa "bling-bling"!
<HR></BLOCKQUOTE>

I use the best thing I've ever found for cleaning/polishing wheels: Griot's Garage Speed Shine. I have not yet used hose and water to wash the car; only Cali Duster and Speed Shine.

I have their orbital machine, wax, clay - though I have not even used them yet.

Griot's Garage is a catalog store. 800-345-5789.

(Consider this thread hijacked.)
supergrin.gif
 

Vic

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Right on, Mike. Say, are you tired of talking about this yet?

Craig, thanks for the tip.

I was almost expecting GTS Bruce to tell me to shut up, cause I jumped on his post with my novel about runners, torque and such. Stop me anytime... I'm such a bore!

seeya.gif
 

Vic

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The Road Star has 99 foot pounds of torque...

<FONT size="6">(Somebody stop me, please!)</FONT s>

Just kidding!

Its just ok, I say that because I can't ride it that long. It seems that the windshield, instead of making my trip more comfortable, is actually causing kind of a vacuum behind my head, which forces me to work to hold my head up, as the wind buffets. Quite literally a pain in the neck!

Maybe if I took the windshield off, that would be better. For the money, I could've had a Suzuki Hayabusa, or Yamaha R1! Some decisions ****...

I am not familiar with the Warrior. After I bought my Yamaha, I just got occupied with my Viper, and you know the rest. But I did see it once in a commercial, and I think you may be right.

You into bikes?
 

Mike Brunton

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Vic,

I have a VTX, an R1 and a 929RR... yeah, I guess you could say I am into bikes
smile.gif


Regarding the wind buffeting - is your windshield adjustable? Usually they can move up or down an inch or two at least... there are alot of guys on the VTX board that had the same problem as you, and usually it's because the windshield causes the air to flow just above your head, and it comes down behind you, causing a low pressure zone sucking you back. If you can adjust it a little, you might notice a world of difference.

Or you could get a Memphis fats for it or something - they seem to be real popular.

Does the roadstar really have 99lb-ft? wow! The VTX's usually make about 115lb-ft to the wheel but that's with an exhaust and PCIII - 99 stock is a whole bunch!
 

Vic

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Yup, 99 slow turning big ones. Runs out of breath real bad, at higher r's. Corners like a ****...

I've got my winshield up as high as it will go, which means I'm looking through top 1" of the screen. (I'm a bit tall) If I run with it down lower, the wind hits my helmet from the front. Sigh...

Howz that R1? I heard they are a blast.
 

Dozer

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2002 Yamaha R1 here, Liquid Silver of course.

The bike is nothing short of incredible. Able to eat just about anything for lunch up at Thunderhill raceway.
smile.gif
 

Vic

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Kewl...

Maybe if I can sneak an R1 past my honey-
 

Bill Pemberton Woodhouse

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From the hallowed halls of Daimler Chrysler Marketing comes.....

Marketing Wars and the Dynamics of Esoteric Verbage and Non Sensical Meanderings to mesmerize the Buying Public.

Large, bearded ,hirsute gentleman with mismatched Hilfiger shirt and flowered tie --- " Heh, Nancy, what we gonna do about this torque thing with the new ******* Snake. "
Nancy, a 4'10" powerbroker with the arms of a longshoreman, and a cute dimple on her left cheek, " Mannie, I just think that describing the new SRT-10 as a 8.3 Liter , 505 hp, 525 ft lbs of torque , beast from the ****** of Detroit, lacks a little pizzazz."
" Well, uh, well,uhhhh...." whispering comments from the wispy haired, beanpole of Ichabod Crane visage, answered any thoughts Nancy and Mannie had that Jerome would come forth with any constructive assistance.
" Ve need continuity, und you vill like it, " stammered a disgusted, v shaped Atlas with a crop of golden locks, cascading over his gray-pinstriped ( with just a hint of red thread interlacing the fabric) Armani suit, at a barely businesslike , shoulder level.
Mannie , Nancy, and Jerome's lips were floodgates of approval without even venturing to understand what Hans was saying, but a tiny burble from the thin, quivering lip of Jerome uttered, "buuuu, buuuttt, what, are weeeeeeeeeee.............

" Basic Marketing, dunderheads," bellowed Hans, as he answered simply.........You don't pace the Indy 500 with a 8.3 Liter, and you don't pace the Daytona 500 with 505 hp." The 500's will be started behind a 500/500/500 beast and who cares if we underestimate the true power -------the 500 by the 500 flows."

" Get back to work and give me an idea by Thursday on what your plans are to market a SRT-4 Neon that will do 165mph" Und have a nice day!
 

Vic

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Bill Pemberton:
From the hallowed halls of Daimler Chrysler Marketing comes.....

Marketing Wars and the Dynamics of Esoteric Verbage and Non Sensical Meanderings to mesmerize the Buying Public.

laugh.gif
laugh.gif
laugh.gif


" Ve need continuity, und you vill like it, " stammered a disgusted, v shaped Atlas with a crop of golden locks, cascading over his gray-pinstriped ( with just a hint of red thread interlacing the fabric) Armani suit, at a barely businesslike , shoulder level.

<FONT size="2">I had to read that twice!</FONT s>

" Basic Marketing, dunderheads," bellowed Hans, as he answered simply.........You don't pace the Indy 500 with a 8.3 Liter, and you don't pace the Daytona 500 with 505 hp." The 500's will be started behind a 500/500/500 beast and who cares if we underestimate the true power -------the 500 by the 500 flows."


<HR></BLOCKQUOTE>

Mmmm, now I see why it has been said that an SRT was seen to have smoked a GTS recently. Under rated power levels! Quick, to the bat cave. The bat mobile is going to need a Sean Roe or equivalent supercharger, or else risk being dusted by some uppity yuppie trash, whose self-satisfied sneer makes my nostrils twitch, with fearsome loathing and trepidation, as he pulls up along side at the light, with his "lighter-than-thou" SRT....
 

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