n/a BETA max hp #'s
07-11-2002, 10:47 AM
#11
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Because it wasn't MADE to. But don't worry, Hyundai CVVT (or whatever its going to be) is on its way if there is any truth to the rumors. Anyways, our engines are not all that strong...they are surprisingly stronger than anyone suspected which is why we are all so enthusiastic about it. Let's face it...Hyundai still has not made a true sports car...designed on its own platform with its own engine and own parts. The 2003 Tiburon is just the tip of the iceberg. There is a long road ahead and its looking pretty bright that they have made such a good design crossing over parts and platforms borrowing from the rest of the models. Now all we need to see is a 3.5L 250hp Tiburon, that would be nice. hehehehe...but I don't think that dinky frame could handle it.
07-11-2002, 11:00 AM
#13
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The S2000 engine that you continualy use for an example was designed and built from the ground up to rev very high. The Tiburon/Elantra engine was designed and built from the ground up for durability while being inexpensive.
The research and development that went into making a production 9000 RPM engine is insane -- everything from fiber-reinforced cylinder walls, to very special bearing materials, block ribbing to resist deformation under severe torsional load, a rotating assembly that comes from the factory balanced within like 0.01 grams...
Don't trivialize 9000 Rpm's as *something easy to do*. That's a $100M USD research project under the hood of the S2K.
Something else to keep in mind:
The only time you want to rev higher is IF your engine can continue making power up there. You don't see 9000 RPM LS6 engines, and yet I don't hear you complaining that Firebirds need a 9K redline...
The research and development that went into making a production 9000 RPM engine is insane -- everything from fiber-reinforced cylinder walls, to very special bearing materials, block ribbing to resist deformation under severe torsional load, a rotating assembly that comes from the factory balanced within like 0.01 grams...
Don't trivialize 9000 Rpm's as *something easy to do*. That's a $100M USD research project under the hood of the S2K.
Something else to keep in mind:
The only time you want to rev higher is IF your engine can continue making power up there. You don't see 9000 RPM LS6 engines, and yet I don't hear you complaining that Firebirds need a 9K redline...
07-11-2002, 11:27 AM
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I believe that the S2000 engine was designed to tolerate pistons speed equal to or greater than a Formula 1 car.
The S2000 engine is an engineering work of art for a production vehicle.
The S2000 engine is an engineering work of art for a production vehicle.
07-11-2002, 01:40 PM
#16
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Vehicle: x3 accent gk tiburon santa fe
<div class='quotetop'>QUOTE </div><div class='quotemain'>For the BetaII, the long stroke is the killer </div>Random, i always tough the stroke and bore was the same in both beta 1 and 2 (2.0l) difference were only for the lifter system
did i miss something?
we also have to take the connecting rod lenght in account too,longuer rods usually make a engine more rev happy (less cylinder walls load,longuer dwell time,better angles)
Denis
did i miss something?
we also have to take the connecting rod lenght in account too,longuer rods usually make a engine more rev happy (less cylinder walls load,longuer dwell time,better angles)
Denis
07-11-2002, 04:53 PM
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Denis,
What you're thinking of is *rod/stroke* ratio, a one of the main engine geometry factors that dictates how well it will rev. You take the length of the rod, divided by the full stroke of the crank. The higher this value, the more rev-happy it will be.
The *perfect* R/S is said to be right around 1.75:1... The Honda B16A2 (US Civic Si and CDN Civic SiR) has an R/S of 1.74:1; the Honda B18C5 found in the Integra Type R has an R/S of 1.72:1.
The Mitsubishi 4G63 has an R/S of around 1.65:1, which is enough to get it winding to around 7800-8000 reliably after modification.
The Hyundai BETA 2.0L has an R/S of around 1.54:1. The general feeling here is somewhere between
and sad.gif
Long stroke, short rods, sucks for revving. What's funny tho is, the 1.8L BETA actually is around 1.7:1 with it's shorter stroke and longer rods in the 2.0L block. Theoretically, it should be able to wind into the 8K range without much drama. I don't have the first clue if anyone's tried that yet...
What you're thinking of is *rod/stroke* ratio, a one of the main engine geometry factors that dictates how well it will rev. You take the length of the rod, divided by the full stroke of the crank. The higher this value, the more rev-happy it will be.
The *perfect* R/S is said to be right around 1.75:1... The Honda B16A2 (US Civic Si and CDN Civic SiR) has an R/S of 1.74:1; the Honda B18C5 found in the Integra Type R has an R/S of 1.72:1.
The Mitsubishi 4G63 has an R/S of around 1.65:1, which is enough to get it winding to around 7800-8000 reliably after modification.
The Hyundai BETA 2.0L has an R/S of around 1.54:1. The general feeling here is somewhere between
and sad.gifLong stroke, short rods, sucks for revving. What's funny tho is, the 1.8L BETA actually is around 1.7:1 with it's shorter stroke and longer rods in the 2.0L block. Theoretically, it should be able to wind into the 8K range without much drama. I don't have the first clue if anyone's tried that yet...
07-11-2002, 04:53 PM
#18
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Sorry, re-reading that, it is a tad misleading.
Long stroke on BOTH motors (beta1 and 2) prevents high RPM operation.
Okay, let's do some math boys and girls
The S2000 has a 87mm bore and a 84mm stroke.
We have a 82mm bore and a 93.5mm stroke
for 6000 RPM, the Honda pistion travels (84x6000) 504000mm, or 504 Meters.
For 6000 RPM the Beta pistion travels (93.5x6000) 561000mm or 561 Meters.
At the same RPM, the pistion has to travel 57 meters farther in one mintue.
The size of the loads generated by piston travel (up down) is proportional to the RPM of the engine, squared. For example, if engine speed is increased threefold, the intertial load will be NINE TIMES as great. The action of the pistion's being pulled (forced to accelerate) to a stop at TDC and then pulled down the bore towards the center stroke will put a tensile inertial load into the conrod/pistion assembly. Similarly, as the pistion is pushed to a stop at BDC and then pushed back up the bore towards the center stroke, the inertial load will be compressive. The largest tensile load induced into a con rod is at TDC on the exhaust gas stroke. These inerial loads are HUGE. A large-displacement engine running 7000 RPM can develop con-rod inertial loads greater than 4,000 lbs. (that's like a cadillac sitting on your rod bearing!).
To sum things up. Because loads increase at the square of engine speed, and because our motors are already long stroke motors, raising the RPM limit is very risky.
Honda motors have large bores and short strokes. This means they have little/no low end torque, but makes them able to rev to 8000 RPM and still make power.
The Beta motor have small bores and long strokes. This means they have low end torque, but makes it hard for them to rev much past 7000 rpm without doing damage.
It's a trade off. For a high reving motor, you lose low end torque. For a low end torque motor, you gain high end power. It is a differnce in design philosphy when the engines were created/desgined, and there is no way to *correct* the situation now. You cannot *shorten* our stroke without loosing much needed displacment. You cannot lengthen honda's stroke without smacking the pistions into the head!
Red-
You should read the writeup SCC just did on rod ratios. In the end, the rod ratio has little to do with *rev* ability compared with stroke length, and has little do with with power ability compared to bore displacement increases.
Long stroke on BOTH motors (beta1 and 2) prevents high RPM operation.
Okay, let's do some math boys and girls
The S2000 has a 87mm bore and a 84mm stroke.
We have a 82mm bore and a 93.5mm stroke
for 6000 RPM, the Honda pistion travels (84x6000) 504000mm, or 504 Meters.
For 6000 RPM the Beta pistion travels (93.5x6000) 561000mm or 561 Meters.
At the same RPM, the pistion has to travel 57 meters farther in one mintue.
The size of the loads generated by piston travel (up down) is proportional to the RPM of the engine, squared. For example, if engine speed is increased threefold, the intertial load will be NINE TIMES as great. The action of the pistion's being pulled (forced to accelerate) to a stop at TDC and then pulled down the bore towards the center stroke will put a tensile inertial load into the conrod/pistion assembly. Similarly, as the pistion is pushed to a stop at BDC and then pushed back up the bore towards the center stroke, the inertial load will be compressive. The largest tensile load induced into a con rod is at TDC on the exhaust gas stroke. These inerial loads are HUGE. A large-displacement engine running 7000 RPM can develop con-rod inertial loads greater than 4,000 lbs. (that's like a cadillac sitting on your rod bearing!).
To sum things up. Because loads increase at the square of engine speed, and because our motors are already long stroke motors, raising the RPM limit is very risky.
Honda motors have large bores and short strokes. This means they have little/no low end torque, but makes them able to rev to 8000 RPM and still make power.
The Beta motor have small bores and long strokes. This means they have low end torque, but makes it hard for them to rev much past 7000 rpm without doing damage.
It's a trade off. For a high reving motor, you lose low end torque. For a low end torque motor, you gain high end power. It is a differnce in design philosphy when the engines were created/desgined, and there is no way to *correct* the situation now. You cannot *shorten* our stroke without loosing much needed displacment. You cannot lengthen honda's stroke without smacking the pistions into the head!
Red-
You should read the writeup SCC just did on rod ratios. In the end, the rod ratio has little to do with *rev* ability compared with stroke length, and has little do with with power ability compared to bore displacement increases.
07-11-2002, 10:37 PM
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To post an extreme, high RPM does not necessarily mean high power.
Look at the Chrysler 2.2/2.5 liter engine family. They were used quite successfully in the IMSA series in the eighties, both turbo and NA, making well over 200HP NA and over 400 Turbo, and never exceeding 7000RPM. Why never over 7 grand?
Because the stroke in the 2.2 is very nearly 4*, and the stroke in the 2.5 exceeds that. Incredibly long stroke = LOADS of torque. But, you can't rev because the long stroke increses piston speeds so much the engine will fly apart.
Somewhere I saw a chart with stroke/rod ratio vs. piston speed. I'd wager to bed the Honda engine has a very short stroke, the Hyundai Beta is in the middle, and the Chrysler engine on the extreme long end. I'd say piston speed are at the danger level at, say, 8500 on the honda (but tech allows topping that), 7500 on the beta, and 6000 on a Chrysler 2.5. Just guessing there, but I'm probably close.
Rod ratio plays into this too, but I don't know the specs on these motors. Rod ratios affect the acceleration curve of the piston and the side loading in the bore.
Look at the Chrysler 2.2/2.5 liter engine family. They were used quite successfully in the IMSA series in the eighties, both turbo and NA, making well over 200HP NA and over 400 Turbo, and never exceeding 7000RPM. Why never over 7 grand?
Because the stroke in the 2.2 is very nearly 4*, and the stroke in the 2.5 exceeds that. Incredibly long stroke = LOADS of torque. But, you can't rev because the long stroke increses piston speeds so much the engine will fly apart.
Somewhere I saw a chart with stroke/rod ratio vs. piston speed. I'd wager to bed the Honda engine has a very short stroke, the Hyundai Beta is in the middle, and the Chrysler engine on the extreme long end. I'd say piston speed are at the danger level at, say, 8500 on the honda (but tech allows topping that), 7500 on the beta, and 6000 on a Chrysler 2.5. Just guessing there, but I'm probably close.
Rod ratio plays into this too, but I don't know the specs on these motors. Rod ratios affect the acceleration curve of the piston and the side loading in the bore.
