Transmission Ideas?

[jimgood]

Hasn't this been discussed enough over on NASIOC? My God. They have an entire forum dedicated just to transmissions with 29,267 threads and 240,544 posts (and counting). Do we really have to clutter up this forum beating this dead horse?

And for the guys that are leaving the mass of the vehicle out of the equation, try this extreme analogy:
Park a fully loaded dump truck on level ground and leave it in neutral
Put a breaker bar on a lug on the right side of the truck
Apply force to the breaker bar until the truck moves

Now put that breaker bar on the axle nut of a child's tricycle
Apply force until the tricycle moves

Given, in this scenario, that you are the engine and the breaker bar is the transmission, which vehicle is more likely to break the breaker bar?

[skullandbones]

I like your analogy. Thinking of that tric, I can imagine how crazy some of those 818 launches will be like!!

I don't think you will get much traction on the NASIOC thing though. When I first heard about it, I thought they were talking about a racing association like SCCA. So not everyone comes from the same auto education and experience perspective. I took advice given me and did go there for some reference that the poster thought would be helpful. I think he even gave me the specific link. So you make a good point that the info is already out there but many don't want to dredge thru a lot of that stuff and some don't want to ever go there for one reason or another (culture, knowledge base, extraneous info, etc). I think some of the people on this forum want to create their own database for the subject material and create iterations that may be similar to what is there but not the same. IMO. WEK.

[bobzdar]

Hasn't this been discussed enough over on NASIOC? My God. They have an entire forum dedicated just to transmissions with 29,267 threads and 240,544 posts (and counting). Do we really have to clutter up this forum beating this dead horse?

And for the guys that are leaving the mass of the vehicle out of the equation, try this extreme analogy:
Park a fully loaded dump truck on level ground and leave it in neutral
Put a breaker bar on a lug on the right side of the truck
Apply force to the breaker bar until the truck moves

Now put that breaker bar on the axle nut of a child's tricycle
Apply force until the tricycle moves

Given, in this scenario, that you are the engine and the breaker bar is the transmission, which vehicle is more likely to break the breaker bar?

This completely depends on what the weak link of the transmission is. If it's 1st gear and you're spinning tires, yes your analogy holds up. If it's 4th or 5th gear (or the differential), your primary load will be the aero resistance and then weight is not that big of an influence, so trying to accelerate at 100mph in 4th gear pushing against that air, it won't matter if the car weighs 3500lbs or 2000lbs, the engine will be putting it's full force through the drivetrain at around the same resistance and 4th or 5th will go pop regardless of car weight. Most drivetrain components are rated for a certain torque load, they don't specify the weight of the vehicle because they can only handle so much force. The advantage to the 818 will be if in lower gears it doesn't have enough traction to break the trans, but if you manage to hook it up, it'll still go boom.

[StatGSR]

[PhyrraM]

MOTIVATIONAL POSTER!

This is now officially Nasioc.

[StatGSR]

your right, we should go back to arguing about things we don't understand.....

[Evan78]

So, is the argument being made that an engine pulled from a WRX will make significantly less power when installed in an 818? If the answer is no, then I don't see how all of these attempts at simple explanations or analogies are applicable.

Work = Force x Distance (W=Fd)
Force = Mass x Acceleration (F=ma)

Substituting the force equation into the work equation yields:

Work = Mass x Acceleration x Distance

In other words, the work performed is the product of the mass (weight of vehicle), rate of acceleration, and the distance covered. Naturally, the work performed by the transmission is going to contribute to wearing out parts. Our conversation is centered around the mass portion, and of course there will be less wear if the mass is reduced and transmissions will last longer, all else being equal.

But another question is how much affect will the reduced mass have on the chances of a structural failure? The conversation here is mixing structural failure (catastrophic failure due to exceeding the strength of the transmission components) and failure due to wear (i.e. towing a heavy trailer). I think lack of clarity on this point is contributing to the differing viewpoints.

This single event failure is the point that I've always been thinking about throughout the conversation since it relates to peak power capability. My interpretation of everyone's comments has been that engine output is assumed to be constant, regardless of what chassis it's sitting in. If the engine output is considered variable, it should be clarified.

[Evan78]

Here's an interesting test of a couple dyno runs (source):

365hp/361tq with dyno set to no load
383hp/378tq with dyno set to 50% load

[shinn497]

So, is the argument being made that an engine pulled from a WRX will make significantly less power when installed in an 818? If the answer is no, then I don't see how all of these attempts at simple explanations or analogies are applicable.

Work = Force x Distance (W=Fd)
Force = Mass x Acceleration (F=ma)

Substituting the force equation into the work equation yields:

Work = Mass x Acceleration x Distance

In other words, the work performed is the product of the mass (weight of vehicle), rate of acceleration, and the distance covered. Naturally, the work performed by the transmission is going to contribute to wearing out parts. Our conversation is centered around the mass portion, and of course there will be less wear if the mass is reduced and transmissions will last longer, all else being equal.

But another question is how much affect will the reduced mass have on the chances of a structural failure? The conversation here is mixing structural failure (catastrophic failure due to exceeding the strength of the transmission components) and failure due to wear (i.e. towing a heavy trailer). I think lack of clarity on this point is contributing to the differing viewpoints.

This single event failure is the point that I've always been thinking about throughout the conversation since it relates to peak power capability. My interpretation of everyone's comments has been that engine output is assumed to be constant, regardless of what chassis it's sitting in. If the engine output is considered variable, it should be clarified.

Evan you are oversimplifying things.

First I don't think anyone has stated that an engine being pulled from a wrx will make less power when put into the 818. IF that was true than no one would build lighter cars.

Second, you can't decrease mass while keeping everything else equal. IF the car weighs less, and the engine makes the same torque, it will accelerate faster. Thus the force equation will not change.

Third, you are using the SCIENTIFIC definition of work. It isn't so intuitive that this is what causes wear. I argue that metals and suspension components are prone to breaking under strain. This is how much they deform when given an applied force...and the force of the engine does not change given what its load is.

As said before, lighter mass cars cause the transmission to experience the same force for less time. It is the impulse that changes.

[Evan78]

First I don't think anyone has stated that an engine being pulled from a wrx will make less power when put into the 818. IF that was true than no one would build lighter cars.

That is part of my point. The argument seems to be that somehow one side of the equation remains constant (the engine) but the transmission sees less stress because the car is lighter DESPITE the fact that the acceleration is greater.

Second, you can't decrease mass while keeping everything else equal. IF the car weighs less, and the engine makes the same torque, it will accelerate faster. Thus the force equation will not change.

Who said the equation would change? Of course the equation doesn't change. I thought it was the clearest way to show that everything balances. If work and distance are constant and we are changing mass, rate of acceleration changes as well. Perhaps you're misunderstanding me when I added "all else being equal". I am using that the way it is always used, to imply that we are holding all other relevant variables constant. Naturally, if you have a balanced equation, changing one value requires changing at least one other.

Third, you are using the SCIENTIFIC definition of work. It isn't so intuitive that this is what causes wear. I argue that metals and suspension components are prone to breaking under strain. This is how much they deform when given an applied force...and the force of the engine does not change given what its load is.

So if work does not cause wear, what does? Sitting at rest? Everything is prone to breaking under strain, I don't think you'll have to argue hard on that point. I even mentioned that in the last 2 paragraphs of my previous post.

As said before, lighter mass cars cause the transmission to experience the same force for less time. It is the impulse that changes.

Yes, that is what PhyrraM said early in this thread that many people seem to disagree with. The peak force is the same regardless of the weight of the car, it is the duration of the force application that changes if both cars are accelerating to the same speed. If that peak force is greater than the transmission can handle, you get transmission failure in either chassis.

[Xusia]

Evan, In all seriousness, I'm very confused as to your point. I mean no disrespect when I say you've made a bunch of statements, but *I* can't find a cohesive point anywhere in them.

Also, the force coming OUT of the engine may be the same, but the force actually EXPERIENCED by the various transmission (and drive train) parts can vary because there are other forces acting on them, such as the inertial resistance of the vehicle, the traction of the tires, etc.

To illustrate: Why is a 2000 lbs. car easier for a human to push than a 6000 lbs. car? Because the extra weight increases inertial resistance. If the force being applied to push it is the same, acceleration will be faster for the 2000 lbs. car (duh). In order for the 2 cars to have the same acceleration, the force pushing the heavier car would have to be greater. I think we all know this intuitively, but it illustrates the formula in action.

So how does this relate the transmission? In the example above the "transmission" would be the human's shoes (they transfer the force being generated to the ground). Even though the force being generated by the human is the same, the shoes are under more stress pushing the heavier car. Again, I think we all know this to be the case intuitively.

What continues to confound me is why these concepts are seemingly so difficult when applied to an engine & transmission...

[Oppenheimer]

The load on trans is not just about lower weight of the car, its also about 2WD vs AWD. Tires can act like a fuse to prevent excess stress on the trans when they break loose. Albeit, a not very well regualted fuse (its not like you can count on the tires to always break loose at a set threshold that is just below that of trans damage).

Lighter car = less overall strain on trans (during times of accel from low speed to overcome inertia)
less grip (less because there is less weight pushing the tires down into the pavement, and because there are now only two tires that count) = less strain on trans (during times of accel from low speed where tires will be more likely to lose traction)

[2KWIK4U]

Also, the force coming OUT of the engine may be the same, but the force actually EXPERIENCED by the various transmission (and drive train) parts can vary because there are other forces acting on them, such as the inertial resistance of the vehicle, the traction of the tires, etc.

Great way to explain it,

[Evan78]

Here are a couple statements I think we can all agree on:

Less mass = easier to accelerate = less stress on transmission
greater acceleration = more stress on transmission

My question is how do you know that the reduction in stress due to the reduced vehicle mass is not offset by the increase in rate of acceleration?

[Xusia]

OK, got it. GREAT question, BTW! My instincts tell me the increased acceleration would have less impact on transmission stress than the lack of mass, but I'm not enough of a mathematician to back that up with numbers. Mechanical losses? The fact that acceleration is squared?? We've got a lot of engineering types on this forum. Someone should have a better answer!

[Arrowhead]

Wow, my head hurts. I did learn something though, I was wondering how it's converted to RWD so I see there is a simple kit available so that's good.

As far as all the other disscussion, I won't even attempt to engage other than my only thought is would it be wise to upgrade the drive axles? I mean all the power is now only split by two instead of four wheels.

[PhyrraM]

...... my only thought is would it be wise to upgrade the drive axles? ...

Years ago, when Subaru still sold FWD versions of thier cars in North America, they had basically the same transmission - but used larger diameter front half-shafts on FWD models. They had no more than 140 HP. Something to think about.

[skullandbones]

I think the 818 tranny will suffer from the same sort of threshold problem the t5 has in the roadster. Under 350 hp, it's OK. After that there is a grey area depending on many factors (setup). At 400+ there is a clear consensus that the t5 won't survive. So there will probably be the same kind of "grey area" for the 818 tanny. I believe we are already experiencing that in the discussion (hypothetical). When these projects start to hit the road and strips, a real answer will begin to sort itself out.

If you stay with a stock WRX, the tranny should work OK stock and if you plan on adding say 75 to 100 hp, then helical gears and upgraded half shafts and associated gear might be the way to go. WEK.

[Flamshackle]

I think the 818 tranny will suffer from the same sort of threshold problem the t5 has in the roadster...

...If you stay with a stock WRX, the tranny should work OK stock and if you plan on adding say 75 to 100 hp, then helical gears and upgraded half shafts and associated gear might be the way to go. WEK.

This ^^^^

Stock tranny will be fine with stock power output. high horse power examples will need high horsepower capable gear sets.

[Evan78]

I think the 818 tranny will suffer from the same sort of threshold problem the t5 has in the roadster. Under 350 hp, it's OK. After that there is a grey area depending on many factors (setup). At 400+ there is a clear consensus that the t5 won't survive. So there will probably be the same kind of "grey area" for the 818 tanny. I believe we are already experiencing that in the discussion (hypothetical). When these projects start to hit the road and strips, a real answer will begin to sort itself out.

If you stay with a stock WRX, the tranny should work OK stock and if you plan on adding say 75 to 100 hp, then helical gears and upgraded half shafts and associated gear might be the way to go. WEK.

That's a great point, the 818 situation is the same as what they've experience - same components in a lighter chassis. Is there much discussion on that topic in this forum or do I need to head over to the old one?

[BrandonDrums]

Here are a couple statements I think we can all agree on:

Less mass = easier to accelerate = less stress on transmission
greater acceleration = more stress on transmission

My question is how do you know that the reduction in stress due to the reduced vehicle mass is not offset by the increase in rate of acceleration?

I think people get mixed up between power and force. Power is force distributed over time or distance. Torque is an instantaneous measure of a twisting force.

This is a difficult conversation in the case of the internal combustion engine as technically speaking, the engine doesn't provide a continual force but is rather driven by a series of pulses evened out by a flywheel. The force of those pulses are variable dependent on the rate of movement in that system. A car doesn't operate on thrust but rather mechanical force which have limits based on the speed relationships of all of those mechanisms.

A rocket however, uses thrust to move and the force being exerted by a rocket is not dependent on speed since it's a simple relationship between the rocket and the gasses being thrown behind it, the rocket doesn't need to have any mechanical systems rotate to match the speed in which it moves through space.

That's probably how people are thinking of this scenario since more classical physics remove friction and other mechanical limits to keep the mathematics principles pure. F=MA always remains true in the case of the motorcar and the case of the space rocket. The difference is the car makes force by applying it to the earth in which the car moves in relation to and the engine is mechanically dependent on that relationship. The rocket simply generates force against itself which has a net relationship regardless of speed.

[Xusia]

Good point Brandon. There is also the issue of wind resistance (a negative force acting against acceleration) - which I purposely omitted to avoid overly complicating the discussion - that would also apply while the vehicle is in motion, in addition to the mechanical relationship you mention.

[shinn497]

I think people get mixed up between power and force. Power is force distributed over time or distance. Torque is an instantaneous measure of a twisting force.

Power is NOT simply force measured over time or distance. Impulse is. Specifically it is the integral of the force function over a period of time.

Assume everything is constant as these would be integral equations if not. I am putting the differential equations in parenthesis).
Energy = Work = Force*distance (dEnergy = dWork = Force (distance)*ddistance)
Power = Energy/time = dE/dt
Impulse = Force*time (dImpulse = Force(time)dtime)

Power is a measurement of instantaneous ENERGY. I.E. it can be directly converted to heat. In a car the input power of the engine goes into the kinetic energy of the car + the loss due to the dirvetrain, rolling resistance, and drag.

Engine power = delta (mv^2)/2 + Paricidic lossess + Drag

In the above examble it is actually rather difficult to measure these paracidic losses furthermore it is even less intuitive to translate the input power of an engine towards the strain of the components. This is why it is better to work with torque and Force.

Also if you must know torque = rXF

Where r is the radius of your spinning object and F is the force at the edge. This is a vector equation. It can also be expressed as:

torque = Iw

With omega equaling the angular velocity and I being the rotational intertia.

torque is useful because it has the same value regardless of the size of the rotating object. If I measure 200 n*m of torque on a wheel of 15 inches it will not change for a wheel of 18 inches.

Agan as we've said time and time again. There is no reduction in force due to vehicle mass. And increased acceleration does not translate to more stress.

If you took an 818 and a wrx and accelerated them for the same amount of time , with the same applied engine torque, the transmissions would experience the exact same stressess. The 818 would end up at a much higher speed, but it would still be just as prone to breaking.

Similiarly if you were to run an 818 at a constant speed on its torque peak (whether it is at its top speed is dependant entirely the the shape of the torque curve), the weight will NOT save you . The transmision is still as prone to breaking as a heavier car in the same situation.

Wind resistance doesn't complicate the situation. It is not even based on vehicle weight be rather the drag coefficient and the cross sectional area. Thus the difference in the 818's top speed will depend mostly on its shape and engine power. This is why it won't have a 200mph top speed like a supercar, but super car acceleration.

[el_jefe]

As long as it's not a bug eye, I'm not going to be concerned with the trans until I am well over 450-500rwhp. Which is where a stock internal EJ is likely to come apart anyway. 90% of the 818's built will not come close to those numbers, and the ones that do will know what to do with the transmission.

[skullandbones]

Ican appreciate your fervor in defending a position but I fail to see how it proves anything specific except that you might be right (debating mode).

I believe I remember that in the force equation, mass and acceleration are inversely proportional. If that is so then I figured that the prototype 818 should have an approximate 38% increase in accelaration with stock engine, transaxle, etc. as compared to the donor (guessed at 2900 lbs).

In the same equation, I think force and acceleration are directly proportional so if you double the force you will double the acceleration. Unfortunately, a lot of people will apply too much f and instead of a they will get b (boom). WEK.

[el_jefe]

*shrugs* No one will be able to "prove" anything until they build a car, and even then since most of the parts will be from a used donor car, the baseline for proof will be suspect.

So instead I will stand by the practical aspect. I see 400hp AWD Subarus racing on stock transmissions all day long (except the previously mentioned bugeyes) with minimal problems that cant be attributed to driver abuse.

Less resistance on the driveline equals less chance for things to pop. I base this on practical experience again, I was building VW based sandrails back in the 80's (very similar to the 818, put an drivetrain in a super light chassis) and on years of building 4x4's. A great example comes from the 4x4 world, my CJ5 happened to use the same U-joints as a friend did in his muscle car. My 100ish hp jeep would go through them like candy, where his 400hp car would rarely need to replace them. Less load (rolling resistance on the street vs rock crawling and off roading) equals less abuse, despite the disparity in power.

The same thing will apply with the 818. In a WRX, the transmission has to deal with more than double the resistance than in the 818. Twice as much contact patch, and twice the weight. The major problem we will be dealing with is wheelspin. edited to add: And possibly wheelhop. I have no idea how subarus are with wheelhop, but it will grenade axles pretty quick as well.

And the final point from a practical standpoint: watch some drag racing. When do you see more drivetrain failures, at launch when the resistance is maximized, or halfway down the track when horsepower is?

[BrandonDrums]

torque is useful because it has the same value regardless of the size of the rotating object. If I measure 200 n*m of torque on a wheel of 15 inches it will not change for a wheel of 18 inches.

Here is where you're getting stuff completely wrong. That torque is constant at the point at which it's applied but if the diamater of the wheel changes that is recieving that torque, the force applied to the pavement is reduced.

That's why people put smaller wheels on their cars for autocross sometimes, it increases the torque at the expense of top end speed.

[skullandbones]

I would love to be at the prototype testing especially for the first launch. Field testing is still necessary no matter how much wind tunnel, supercomputer time, or other simulations you employee (not to diminish anything done in development so far). So if what you say regarding the VX and sandrail experience is transferable, the stock transaxle should work pretty well for most applications. It would be good to know (with calculations) where that line is crossed so you know when a more bulletproof trans is needed. Speaking of that, when discussing the Legacy and some other models does an upgraded trans mean a beefier tranaxle or just different such as gear ratios, etc? Thanks, WEK.

[shinn497]

Here is where you're getting stuff completely wrong. That torque is constant at the point at which it's applied but if the diamater of the wheel changes that is recieving that torque, the force applied to the pavement is reduced.

That's why people put smaller wheels on their cars for autocross sometimes, it increases the torque at the expense of top end speed.

I am not wrong.

Torque is a vector quantity. It cannot necessarily be applied at a specific point. If a wheel is turning. The torque is the same regardless of its diameter.

The torque at 10 inches is the same at 18 inches is the same at 3 million miles. However, for convenience, torque is expressed in the middle of the object and points perpendicular to the direction of rotation. The direction it points is determined by the right hand rule.

Force is not torque. They are separate quantities with different units. I.e. Torque = Newton*Meters (foot-ibs) Force = Newtons (ibs).

I should note that that statement makes no mention of the force. If you rate an engine you can have no knowledge of the gearing, driveshaft size, and final drive ratios. This is why it torque is advantageous. Of course this is also dependant on how its mounted.

Of course this is all semantics and not really related to the current discussion.

[jimgood]

A lot of talk for such a little problem. I brought up NASIOC because the solution for attaining a stronger WRX transmission has been solved many times over. If you're really worried about putting 250+ lbs/ft torque through the drive line mounted in your 818, then go find one of those solutions and be done with it. For all I know, the op works for one of those gear set vendors and is here merely to plant seeds (and you're very naive if you don't think this type of thing happens all the time on the internet).

[PhyrraM]

...... No one will be able to "prove" anything until (a few cars are built)......

Well said.

[PhyrraM]

.... the solution for attaining a stronger WRX transmission has been solved many times over. If you're really worried about putting 250+ lbs/ft torque through the drive line mounted in your 818, then go find one of those solutions and be done with it. .......

This will only apply if the weak point doesn't move when converted to 2WD.

The front diff, ring and pinion, pinion shaft, and possibly more never saw more then 130ish ft/lbs in an OEM 2WD transmission. All of those have not seen significant upgrades because they are usually seeing only 50% of total power.

That being said, I still feel that ANY year 5 speed will be fine in 95% of non-abused driving. Drop the clutch or "slam-shift" and all bets are off.

[BrandonDrums]

I am not wrong.

Torque is a vector quantity. It cannot necessarily be applied at a specific point. If a wheel is turning. The torque is the same regardless of its diameter.

The torque at 10 inches is the same at 18 inches is the same at 3 million miles. However, for convenience, torque is expressed in the middle of the object and points perpendicular to the direction of rotation. The direction it points is determined by the right hand rule.

Force is not torque. They are separate quantities with different units. I.e. Torque = Newton*Meters (foot-ibs) Force = Newtons (ibs).

I should note that that statement makes no mention of the force. If you rate an engine you can have no knowledge of the gearing, driveshaft size, and final drive ratios. This is why it torque is advantageous. Of course this is also dependant on how its mounted.

Of course this is all semantics and not really related to the current discussion.

http://en.wikipedia.org/wiki/Torque#Machine_torque

~Machine torque

Torque is part of the basic specification of an engine: the power output of an engine is expressed as its torque multiplied by its rotational speed of the axis. Internal-combustion engines produce useful torque only over a limited range of rotational speeds (typically from around 1,000–6,000 rpm for a small car). The varying torque output over that range can be measured with a dynamometer, and shown as a torque curve. The peak of that torque curve occurs somewhat below the overall power peak. The torque peak cannot, by definition, appear at higher rpm than the power peak.

Understanding the relationship between torque, power and engine speed is vital in automotive engineering, concerned as it is with transmitting power from the engine through the drive train to the wheels. Power is a function of torque and engine speed. The gearing of the drive train must be chosen appropriately to make the most of the motor's torque characteristics. Power at the drive wheels is equal to engine power less mechanical losses regardless of any gearing between the engine and drive wheels.
Steam engines and electric motors tend to produce maximum torque close to zero rpm, with the torque diminishing as rotational speed rises (due to increasing friction and other constraints). Reciprocating steam engines can start heavy loads from zero RPM without a clutch.

[RossLH]

Torque is a vector quantity. It cannot necessarily be applied at a specific point. If a wheel is turning. The torque is the same regardless of its diameter.

The torque at 10 inches is the same at 18 inches is the same at 3 million miles. However, for convenience, torque is expressed in the middle of the object and points perpendicular to the direction of rotation. The direction it points is determined by the right hand rule.

Force is not torque. They are separate quantities with different units. I.e. Torque = Newton*Meters (foot-ibs) Force = Newtons (ibs).

Torque is a rotating force. It is the result of applying a linear force at some distance from an axis. This concept can be approached from the other direction as well--a torque at an axis can be translated into a linear force some distance from said axis. For instance, if you have an axle supplying 200Nm to a wheel 2m in diameter, the linear force at the outside of the wheel is 100N. Now, say you replace that 2m wheel with a 1m wheel, the linear force at the edge of the wheel is now 200N (ignoring mass, friction, etc).

So while you are right in saying the torque will not increase when you use a smaller wheel, understand that the same amount of torque at the axle means a greater force on the ground.

[skullandbones]

A lot of talk for such a little problem. I brought up NASIOC because the solution for attaining a stronger WRX transmission has been solved many times over. If you're really worried about putting 250+ lbs/ft torque through the drive line mounted in your 818, then go find one of those solutions and be done with it. For all I know, the op works for one of those gear set vendors and is here merely to plant seeds (and you're very naive if you don't think this type of thing happens all the time on the internet).

Just for the sake of reeling this debate by a few back into the focus of the thread, could you mention one of those "solutions" that you have seen on NASIOC? I'm sure there are as many as there are vendors but are there some that are budget friendly that would still do the job for a modified engine? Thanks, WEK.

[RossLH]

In my experience (and backed up by some numbers I crunched a while ago), if you break a stock transmission and replace it with a budget friendly fix, you'll break that too. The budget friendly designs do not address the main issue at hand, that being the narrow, unsupported length of the main shaft that sits over the front diff. This one unfortunate design element allows the shaft to flex, pulling the input shaft away from the output shaft at 2nd gear. Without adding support to that area of the main shaft, the same thing will happen with an upgraded gear set. The not-so-budget-friendly builds do address the problem, which is why you don't hear as much about them breaking.

Having that said, for a budget build you could do Legacy GT or STi RA gears. A step above that will get you MFactory gears, and the best (as reflected by the price) replacement gears are PPG gears.

[skullandbones]

That's good to hear! Do the more expensive gear sets include that beefier input shaft? I would assume they do but not familiar with this technology. I think one person mentioned upgrading to a stronger case, as well. Thanks for answering my questions.

One reason I don't want to participate in the NASIOC forum at this time is that I really don't have the time to cover that much ground in the time I have available for surfing and researching. I probably will go there more after things begin to solidify and I have specifics that relate to the project/build. If a vendor is pfishing to get more business let them bring their discussion to this forum. Easier for all of us! Thanks, WEK.

[RossLH]

The case is not an issue. Whoever started the myth of the case flex deserves a hearty smack in the face.

Regardless, yes the more expensive gear sets do have beefier input shafts. The only gear set that I will recommend is a PPG gear set. Yes, they're a bit pricey, but there's a reason you dont hear much about them breaking.

[el_jefe]

MOTIVATIONAL POSTER!

This is now officially Nasioc.

I hope not.


I'm permabanned at NASIOC

[Oppenheimer]

All the discussion about if reduced mass has any effect on trans load all seem to be assumming that traction is constant. The rock and hard place that the trans is between is the motor supplying the torque and the tire/road interface that is applying the resistance. Should the tires lose grip, the trans doesn't feel the load. With only 2 wheels to drive through with less weight pushing them into the tarmac (albeit with more weight on them then most front engine RWD designs), there simply won't be as much traction.

The more power the more likely the trans will not hold up, yet the more likely that tires won't be able to hold traction. We simply don't know if there will be enough hookup, with what tires sizes/compounds, at what hp/torque numbers, to make trans weaknes an issue. This is why all these dicussions are as acedemic as they sound until we get real world expereince with the 818.