Interesting EG33 output comparison...

[Chiketkd]

Originally posted by drivemusicnow
^is not true... autos and manuals are completley different, go onto www.howstuffworks.com for a halfway decent explanation of each.

For better/more fun explanation... go to a junkyard, buy one of each, and tear them apart and try to rebuild them

My aim wasn't to give the most in depth description. The two transmissions are vastly different, but the torque convertor easily stands out as the major difference.

-Chike

[Chiketkd]

Originally posted by oab_au
Yes that was a pretty vague description of how a torque converter works. The missing component is the Torus or Stator. This is the bit that produces the torque multiplication.

You're right Harvey. The Stator (kinda like a pump) is the actual device that causes the multiplication of torque.

I was really trying to be brief in my explanation though...I thought about mentioning the stator but left it out to keep things simple.

I look forward to reading your write-up.

-Chike

An automatic trans. and torque converter combo can be built as strong and nearly as efficient (near 0 loss) with equally hard shifts as a manual.

It can't be done and then sold in a car that someone is going to drive up and down the highway in comfort day in and day out.

[Sonar]

A funny thing about gearbox'es and losses is that there IS a automatic gearbox and has been for quite a while, wich has LESS losses then a manual !!!
And best of all.....-in a SUBARU

The so called CVT or ECVT gearbox is a fully automatic and also STEPLESS gearbox, and has been used in the Justy ECVT model.

The concept is very similar to a snowmobile "gearbox" and was developed at DAF in Holland back in the late 60's .

The DAF gearbox used a rubber belt between the pulleys, and the "engine" pulley, "dragged" the belt to transfer the power.

The new CVT approach instead used a metal belt, and the engine acually PUSHES the belt to transfer the forces.

The box is in the "E"CVT electronically controlled and therefore maybe more eff. and configurable than the standard CVT.

In late implementations of the CVT tech. they have built in "steps" so the driver can actually "feel" the next gear, this is because many didn't like the "stepless" feel of the CVT.
In this way it is possible to "program" as many gears you like
and best of all, diffrent "lenght" between every gear!



/Sonny

[Sonar]

..check it out

(ctrl-F and search for BMEP , or anything else )

...And don't forget the turbo calculator

..and HERE are my figures on the SVX in the calculator, notice the incredible VE of 104%


/Sonny

[Sonar]

This is my dream SVX calculated



/Sonny

[SilverSpear]

Originally posted by Chiketkd
It's very hard to compare the SVX to current cars as the EG33 was developed before variable valve timing was common in production vehicles (think only the '91 NSX used it back then).

Decided to compare the specific hp/liter and torque/liter outputs of the EG33 vs the naturally aspirated models offered in the MKIV Supra, Z32 300ZX and 3000GT which were in its price range and performance class. Results are shown below:

300ZX
2960cc
222hp & 198lb-ft
75 hp/l & 66.89 lb-ft/l

Supra
2997cc
220hp & 210lb-ft
73.4 hp/l & 70.07 lb-ft/l

3000GT SL
2972cc
222hp & 201lb-ft
74.69 hp/l & 67.63 lb-ft/l

SVX
3318cc
230hp & 228lb-ft
69.3 hp/l & 68.72 lb-ft/l

While the hp/l output of the EG33 is a little below the others, the lb-ft/l output is right in the mix of things which is probably a testament to the IRIS system Subaru developed.

Another observation is that the hp and tq values are almost identical on the SVX, but significantly different on the other engines. Seems like Subaru tuned the EG33 with torque in mind. I'm sure they could have tuned the engine to make ~240hp & 215lb-ft, but probably due to the car's heavy curb weight, 4EAT trans and awd drivetrain, the SVX needed all the torque the engine could muster...

-Chike

taking the engine alone, with no consideration the weight or so, I guess they could have produced an output of 260 hp very easy. you are comparing a 3.3L to 3.0 L why not comparing it to the 350Z ? with 280hp ? ... also IT'S A BOXER ENGINE FOR GOD'S SAKE !!! you can also compare the 3.0L 24Valves mercedes benz also, a smaller size engine with 217 - 224 HP and a torque BORN IN HELL.... so I guess the SVX's EG33 is like a pussy comparing to the others !!

[drivemusicnow]

Originally posted by SilverSpear


taking the engine alone, with no consideration the weight or so, I guess they could have produced an output of 260 hp very easy. you are comparing a 3.3L to 3.0 L why not comparing it to the 350Z ? with 280hp ? ... also IT'S A BOXER ENGINE FOR GOD'S SAKE !!! you can also compare the 3.0L 24Valves mercedes benz also, a smaller size engine with 217 - 224 HP and a torque BORN IN HELL.... so I guess the SVX's EG33 is like a pussy comparing to the others !!

.... seriously.. try to comprehend everything he was trying to do.. look at the time fram all of those engines existed in... all from about the same time. therefore much more comperable to each to each other. considering its MEP compared to other engines during the same time frame, the EG33 is quite efficient, however, always room for improvement

[drivemusicnow]

Originally posted by Sonar
A funny thing about gearbox'es and losses is that there IS a automatic gearbox and has been for quite a while, wich has LESS losses then a manual !!!
And best of all.....-in a SUBARU

The so called CVT or ECVT gearbox is a fully automatic and also STEPLESS gearbox, and has been used in the Justy ECVT model.

The concept is very similar to a snowmobile "gearbox" and was developed at DAF in Holland back in the late 60's .

The DAF gearbox used a rubber belt between the pulleys, and the "engine" pulley, "dragged" the belt to transfer the power.

The new CVT approach instead used a metal belt, and the engine acually PUSHES the belt to transfer the forces.

The box is in the "E"CVT electronically controlled and therefore maybe more eff. and configurable than the standard CVT.

In late implementations of the CVT tech. they have built in "steps" so the driver can actually "feel" the next gear, this is because many didn't like the "stepless" feel of the CVT.
In this way it is possible to "program" as many gears you like
and best of all, diffrent "lenght" between every gear!



/Sonny

I work for ZF, and in the heavy duty trucks and coaches, we have a transmission called the "AS-Tronic" eventually i believe they'll try to put these in cars, but all in all, its a manual transmission, with the clutch, 4 "gears" and 2 sets of "low-high" gears are all operated by a computer with a pneumatic interface. Basically you have little air pistons that move the "shift linkage" through 1-2-3-4, and because there are also 1-2 sets of low-high (a splitter group and a "range" group) you can get up to 16 speeds...
Because it is a manual transmission, you lose a lower percentage of torque/hp loss through the transmission, and it can handle HUGE amounts of power... the onhighway one can take 2000lb*ft plus of torque.

I think this is a better way to do "automatic" transmissions than the current setup..

[SilverSpear]

Originally posted by drivemusicnow



.... seriously.. try to comprehend everything he was trying to do.. look at the time fram all of those engines existed in... all from about the same time. therefore much more comperable to each to each other. considering its MEP compared to other engines during the same time frame, the EG33 is quite efficient, however, always room for improvement

Why should I improve it out of my pocket and not SUBARU at the time?

[mbtoloczko]

Originally posted by SilverSpear


... you are comparing a 3.3L to 3.0 L why not comparing it to the 350Z ? with 280hp ? ...

Nissan claims 287 bhp for the 350z motor. The MEP for this car (as I have calculated it) is 13.23 which puts it a bit better than the EG33. Chalk up the better MEP to variable intake timing and probably a slightly more performance oriented motor.

[Sonar]

..just click HERE and change the AFR to let's say 12:1



/Sonny

[b3lha]

Originally posted by Sonar
... there IS a automatic gearbox and has been for quite a while, wich has LESS losses then a manual !!!
And best of all.....-in a SUBARU

The so called CVT or ECVT gearbox is a fully automatic and also STEPLESS gearbox, and has been used in the Justy ECVT model.
...

I've heard it has some similarities to the SVX gearbox, from a non-technical perspective.

http://www.epinions.com/auto-review-...39EDD8EE-prod4

[Sonar]

... I had my car into the dealer about 7 times because of this ECVT....

-oops ...



/Sonny

[oab_au]

All these engines are virtually the same. They all have a cylinder size of between 500 to 550 cc, all use a four valve, pent roof combustion chamber. All have fuel injection and tuned inlet and exhaust systems. Their torque producing capacity or volumetric efficiency will be very close. Nearly all engines follow the same design.

The difference between them is how the torque is to be used in the car to be produced. If it is to be a commuter or 'shopping trolley', the torque peak is placed at around 4000 rpm to give good low rpm performance and pick-up at legal speeds. If it is to be a sports type car with a 5/6 speed box, it will have the torque peak moved up to around 6000 rpm. Same engine, different HP results.

The designed peak torque rpm is set by placing the inlet valve fully opening position (lobe center) at the desired rpm for the torque peak to occure. Within reasion, the torque level will be the same, but as in the sports version, the HP will be higher, because the torque peak is occuring at a higher rpm.

To compare these type of engines, the torque curve is the most informative sorce. Is the curve peakey, or long and flat? The higher the rpm that the torque is produced, the peakey the curve is, as more reliance on resonate technology is used, as these are dependant on a particular rpm, the torque will fall off quickly either side of the peak torque rpm.

To get around the peakey nature of resonate tuning, we have versions with two tuned inlet tracts, a low range centered around 3500/4000 rpm and a higher speed tract at around 5000/6000 rpm. When this is used along with a variable inlet timing (it moves the lobe center to suit two different rpms) the torque peak can be spread over a wider range of engine speeds.

The SVX does it better at the low speed end with the inerta system, as it produces a far higher VE at low rpms than a low speed tuned system can.

Numbers don't tell you much about how the car will preform. The torque curve tell you everything.

Harvey.