Optimax Lightened & Balanced FW gives Rapid Acceleration!!!!

[beyondhelp]

Originally Posted by 2jz

Im a engine builder and tuner myself. engine management systems accel dfi,Pro efi,hondata,AEM,fast,motec. As a tuner i cant see how its hard for not to believe DAVE in his findings. If dave can feel difference in his pants im sure a dyno will see the changes also. Now as far as dyno you have engine dyno and chassis dyno. Any engine would make less HP on chassis because of drivetrain. (mass,load) On dyno you power cure and HP increase with less rotating mass. Not personal its just facts

Its not fact though, It's wrong. How a lighter flywheel can show more HP please for a fixed fully loaded engine power measurement? You are aware that the ramp rate of a dyno should be such that the mass of the rotating parts is mostly irrelevant, Which is why you wouldn't do a power run in lets say 1st gear (assuming traction wouldn't be an issue). An inertia dyno would show more power, but if you looked at the fuel flow and oxygen content actual thermal power would remain the same.

If you take your example to the extreme an engine with no mass in its rotating parts would generate infinite power... Clearly that's not the case. Again this is thermodynamics and physics.

The problem I have here is its being misrepresented, if you want to use an inaccurate method to measure power and show supposed gains by lightening the rotating mass and thus giving a false idea of increased power then fine, but its incorrect.

One really simple way of looking at it. Does a lightweight flywheel at WOT rpm allow the engine to consumer more fuel and air (thus make more power) than an engine with a heavy flywheel. My answer is no. Does a light flywheel improve the engines BMEP? Again, no. Does it reduce the rotating mass allowing quicker engine acceleration? Yes, but once power in = power out and the engine stops to accelerate it wouldn't matter if the flywheel weighed 1kg or 100kg. The power to the prop would be the same.

Cool video, even if I can't see their logic.

[beyondhelp]

Originally Posted by Banana Shark Dave

If you are saying it takes you longer to reach certain speeds, you now need to adjust your props.

I ditched 3 blade props after I fitted my lightend FW as they simply wouldn't bite.

I now use Bravo 1 props and Rev4 props. I also adjust the exhaust tube/defuser length as you will find you get very pronounced stern lift if you don't and your boat will almost bow steer.

When you get that tube length exactly correct and you need to fine tune in 2-3mm increments, other wise you will simply miss the sweet spot. Takes awhile as from the trailing edge of the blade to the end of the tube is 68.5mm. I know what length to start searching for the 'sweet spot' on my boat and several others and from that info I can make a well educated guess what will suit most boats.

That " Sweet Spot" will give you a sudden 4-8mph jump in speed!!!!

I fully lighten, blend and polish the insides of the hubs on these props and can remove from stock weight around 2kg in weight, including the loss of blade weight as well.
This again gives them great acceleration and a Top speed increase over stock weight.

I have various rev4 props with the hubs modified and the blades untouched and stock props to back this up!!! This isn't a discussion I want to get into today.
If you don't believe it and your genuinely interested in purchasing a worked prop then simply PM and arrange to come and test with me.

Sadly my boat isn't really suited to this kind of top speed testing. But I find your findings above interesting. I can see that if you had a light flywheel that the prop could be come very hard to manage if its on the edge of cavitation anyway. So that's quite interesting stuff.

Like I said, I am NOT trying to knock you or your work. Just simply saying what I've said above.

[Banana Shark Dave]

beyond help I still don't know your name and since you want to involve yourself so much in my business it might be nice if we were introduced!!!!

BE MY GUEST AND COME AND HAVE A ALL EXPENSIES PAID DAY OUT ON ME.

I WILL HAPPILY BUY YOU A RETURN TRAIN/COACH TICKET, OR BUY YOUR FUEL.

I WILL BUY YOUR BREAKFAST AND YOUR LUNCH AND YOU ARE MORE THAN WELCOME TO USE MY BOAT TO CONDUCT BOTH LIGHTENED FLY WHEEL AND LIGHTENED PROP HUB TESTING.

YOU CAN DRIVE THE BOAT.

HOWEVER WHEN YOU ARE PROVED WRONG, I SIMPLY ASK FOR AN APPOLOGIE AND IF IM WRONG I WILL.

WHEN WOULD YOU LIKE TO COME????

If you are not prepared to come and test for yourself, I suggest you keep your opinions to yourself!!!

[racefan]

That's some pretty wild claims being made for an increase in top speed from a lightened flywheel...

I don't claim to know the answers, but I'd certainly be interested to hear what sort of additional horsepower it would take to have a speed increase of 2-3mph in the 70+ mph range?

I'm sure I've seen a formula somewhere that would shed light on it, as I find it hard to believe of a speed increase that could easily be measured. Perhaps a trip to Conniston is required, their speeds are pretty spot on, unlike a gps in a boat, which obviously doesn't take into account tides etc.

[2jz]

Originally Posted by beyondhelp

Its not fact though, It's wrong. How a lighter flywheel can show more HP please for a fixed fully loaded engine power measurement? You are aware that the ramp rate of a dyno should be such that the mass of the rotating parts is mostly irrelevant, Which is why you wouldn't do a power run in lets say 1st gear (assuming traction wouldn't be an issue). An inertia dyno would show more power, but if you looked at the fuel flow and oxygen content actual thermal power would remain the same.

If you take your example to the extreme an engine with no mass in its rotating parts would generate infinite power... Clearly that's not the case. Again this is thermodynamics and physics.

The problem I have here is its being misrepresented, if you want to use an inaccurate method to measure power and show supposed gains by lightening the rotating mass and thus giving a false idea of increased power then fine, but its incorrect.

One really simple way of looking at it. Does a lightweight flywheel at WOT rpm allow the engine to consumer more fuel and air (thus make more power) than an engine with a heavy flywheel. My answer is no. Does a light flywheel improve the engines BMEP? Again, no. Does it reduce the rotating mass allowing quicker engine acceleration? Yes, but once power in = power out and the engine stops to accelerate it wouldn't matter if the flywheel weighed 1kg or 100kg. The power to the prop would be the same.

Cool video, even if I can't see their logic.

SMH The Hp gain is coming from the lightened rotation mass that was robbed from drivetrain. Ex an engine makes 300hp on dyno. Now bolt it up to lower unit it make 250hp at the props a loss of 50hp because of drivetrain mass robbing power. If you lighten the rotation mass you gain back some of that power that was lost. Heavier objects need more power to move simple science. So facts of power in = power out is so wrong. Now you say your an engine builder and tuner. if a customer says he or she wants 650hp to the wheels you know the engine has to make 100-200hp more for that to happen.

[Paul E]

A lightened flywheel absolutely positively does NOT give you more horsepower. It may have other effects that may feel like more horsepower, but it isn't more horsepower.

[2jz]

Originally Posted by Banana Shark Dave

Let's really open up this Testing offer to Everyone.

Ok calling Mercury 3.0l and 3.2l optimax engine owners

I am offering a 28 day Money back Gaurantee

If you fit one of these FW's and your not 100% happy simply return it and a full refund will be given, excluding P&P

All I ask is that you test with a prop that doesn't currently hit the Rev limiter.

I make lightened FW's for all lots of engines, so if you want one just PM me.

I wish performance parts shop gave that kind of offer. I would buy parts and not think twice about it. A man that stand behind his work cheers dave.

? if you get flywheel down to 4989 grams will it have stalling issues

[Banana Shark Dave]

Originally Posted by Banana Shark Dave

Super Light Weight Mercury Optimax Flywheels for 3.0 and 3.2 litre 200hp 225hp 250hp 300hp

I can get these flywheels down to 4516 grams!!!!! See pics on my FB page David Webber profile pic is a rib.

If you want really rapid acceleration and a top end gain of between 1-4mph ( speed gain on props that are slightly over pitched) this is it!!!

I am currently totally out of stock and all incoming 2nd FW are sold!!!

I can only machine and balance your FW and return. All work completed with in 7 working days, but usually in 3/4 days.

For FW at 5221 grams that have no occasional stalling at tick over £150 plus shipping.

For " Stealth FW" these are next to impossible to see they have been lightened whilst fitted and very hard to see when they have been removed. The only way is to put them on the scales. I can usually remove around 1000grams PM me for info!!!

FOR THE VERY LIGHTEST FLYWHEEL YOU CAN BUY, A STAGGERING

4516 grams ONLY!!!!!!!

For only £250 plus shipping!!!!

The only thing you can buy close to that is a very soft aluminium 4350 gram one with a steel ring gear for a staggering $1599!!! Sold by a company in the US

Hi anything lighter than 5221grams will have occasional stalling issues.

Anything that is powered from the engine robs power. Be it air con, alternators, this is widely accepted. So why is it so hard to believe the reverse is true????

[Paul E]

Putting lighter wheels on Chris Hoy's bike doesn't make his legs stronger. It makes the bike easier to get to top speed, but that top speed won't change.

[Childsy]

Originally Posted by Paul E

Putting lighter wheels on Chris Hoy's bike doesn't make his legs stronger. It makes the bike easier to get to top speed, but that top speed won't change.

That's a great shout Paul & so very true....!!

[2jz]

Originally Posted by Paul E

Putting lighter wheels on Chris Hoy's bike doesn't make his legs stronger. It makes the bike easier to get to top speed, but that top speed won't change.

Comprare apples to apples.

Add 8000 grams to chris hoys bike top speed will change

Everything and anything that is lighter will be faster simple

[blackbeard]

[beyondhelp]

Originally Posted by 2jz

SMH The Hp gain is coming from the lightened rotation mass that was robbed from drivetrain.

A fly wheel is NOT drive train. There are NO losses in a flywheel, other than frictional air losses.

Ex an engine makes 300hp on dyno. Now bolt it up to lower unit it make 250hp at the props a loss of 50hp because of drivetrain mass robbing power.

Yes agree except Id be surprised if 50hp was lost in one 90 deg gear pinion and bearing(s). If so the gearbox would dissipate 37kw of heat...

If you lighten the rotation mass you gain back some of that power that was lost.

Incorrect. What you are only saying would appear 'true' on an inertia dyno. It would make NO DIFFERENCE for a constant load dyno where power is NOT measured by the rate of acceleration of a known mass.

Heavier objects need more power to move simple science.

A flywheel is quoted as a store of "angular kinetic energy". I will say again: You could have a 100kg flywheel on a 100hp engine, OR a 1kg flywheel, Other than the drag caused by weight of the heavier flywheel once up to lets say 6000 rpm and if you HELD IT THERE by applying the same amount of resistance to the energy out you would measure the opposing torque required to hold both engines at 6000 rpm as EXACTLY THE SAME. The flywheel makes NO difference once the engine RPM has stabilised. A really obvious example of this is in 5th or 6th gear in a car at 100+ mph you CANNOT tell if the engine is fitted with a light flywheel or not, where as in 1st gear its obvious as the time required to transfer the angular kinetic energy to the flywheel is MUCH less on the lighter one. But go up a steep hill were the load out = load required to maintain speed and again you wont be
able to tell if there is no change in RPM. Power is the same.

So facts of power in = power out is so wrong.

just explained why that is not the case.

Read more here:
http://en.wikipedia.org/wiki/Rotational_energy
http://en.wikipedia.org/wiki/Kinetic_energy
and there is LOADs more about it here:
http://en.wikipedia.org/wiki/Classical_mechanics

It all applies from particles of motion right upto lumps of metal in an engine.

Now you say your an engine builder and tuner. if a customer says he or she wants 650hp to the wheels you know the engine has to make 100-200hp more for that to happen.

Agree usually accepted of around 25% for a 4wd transverse engine (the kind I specialise in). But I can tell you one thing for SURE, if I build an engine do a full power dyno test with the dyno holding a FIXED RPM, there will be NO difference in power between one with a light flywheel and one with a heavy.

[cossie69]

Just read all this thread and i would love someone to go and test this and put this issue to bed once and for all, just the fw change and see if there is a difference and post results on here, if i was down that way i would do it no prob,

[beyondhelp]

Originally Posted by Banana Shark Dave

Hi anything lighter than 5221grams will have occasional stalling issues.

Anything that is powered from the engine robs power. Be it air con, alternators, this is widely accepted. So why is it so hard to believe the reverse is true????

Because simply put a flywheel is a store of energy. It doesnt add or loose anything that the engine produces it, it just stores it, nothing more nothing less.

As a side note, making very light flywheels can cause more stress on transmission/gearboxes etc. The reason is that the flywheel would usually absorb the acceleration during each cylinder power stroke and then release it during the remaining non firing portion of crank rotation. Without the flywheel to do this, the rapid but short (only during a power stroke) forces will instead be transferred to the next connected part under load (transmission).
This problem is what resulted in the development of dual mass flywheels to isolate the transmission from these rapid acceleration power stroke loads. So then the DMF became another expensive thing to break so people replaced them with solid ones in some cases to find they break other things instead...

[beyondhelp]

Originally Posted by 2jz

Comprare apples to apples.

Add 8000 grams to chris hoys bike top speed will change

Only if it affects aerodynamics or frictional losses of the tyres to the road. The extra mass wont make any difference to stop speed other than acceleration.

Here is an interesting thought too which again proves this point.

Ignoring wind resistance, Car A and car B have the same engines, The gearing is fixed. For purposes of demonstration they are identical except that car B carries 500kg more. Both are allowed to accelerate for 20 seconds from standstill at full throttle, then they must shut down the engine and roll to a stop, via rolling resistance between tyres and the road alone.

Who ultimately rolls the furthest and why?

If you still cannot picture this then try this. You and your mate are on sledges in the snow. He weights twice as much as you, you both can run at the same speed and jump on the sledges at the same time. Who ends up the furthest?

These are all examples in different ways of stored kinetic energy. Which a flywheel is another one of.

Ill refer to the very first example of WHAT the purpose of a flywheel is (again)

Common uses of a flywheel include:

Providing continuous energy when the energy source is discontinuous. For example, flywheels are used in reciprocating engines because the energy source, torque from the engine, is intermittent.

And by intermittent this refers to the power cycles between which there is no torque to drive anything, and thus during this time power is provided by the stored energy within the rotating mass of the engine and flywheel.

That's enough I think for now

[Paul E]

Originally Posted by 2jz

Comprare apples to apples.

Add 8000 grams to chris hoys bike top speed will change

Everything and anything that is lighter will be faster simple

Originally Posted by beyondhelp

Only if it affects aerodynamics or frictional losses of the tyres to the road. The extra mass wont make any difference to stop speed other than acceleration.

Beyondhelp knows his apples.

Land speed record streamliners at Bonneville pay no attention to weight saving in their cars, because ultimately it makes NO difference to top speed. Many actually add weight for stability! Minimal drag, minimal rolling resistance (a form of drag) and big power is what it takes to see top speed. Dragsters on the other hand take weight saving very seriously, because it's an acceleration contest.

If you took your boat to Coniston Dave and did back to back runs, and the only thing different was the flywheel, your speeds would be the same. Acceleration is meaningless there, as long as you're at top speed when you enter the flying kilometre course.

[Toffy]

Hi all, I've read this thread with increasing interest.

First of all, everyone agrees on the fact that lightened flywheels improves rpm acceleration of the motor. That's what they do, that's what they are known for.
So the only true remaining issue is if they can increase boat topspeed yes or no.

I must say 'beyond help' his explanations are very true. You cannot question the scientific facts he brings on.
I also must say 'Dave' his offer and experiences and top end gains seem very fair. You cannot question the results of a live and fair test.

If I were 'beyond help', I'd take Daves offer and test this together only changing the flywheel, no prop change or whatever. Confronting a non-believer to a believer should bring up a fair end result. And drink a beer afterwards, should be fun too.
Be prepared to actually experience top end increase. I see other known suppliers of lightened outboard flywheels that also promise top end gains.


So let's take this a step further, and let's assume it actually does lead to top end gain.
Then I would like to understand why...

we can all understand that
1. less weight on the boat will lead to top end increase. ( our neverending quest for reducing weight on speedboats, but in this case it's only 2kg with regard to the flywheel....)
2. less weight on the flywheel will lead to hp increase at the prop as it has less rotational mass. (but we are talking only 2kg less weight that needs to be kept in rotation, and as beyondhelp nicely explained this amount of hp or engery is regarded as zero and you don't change anything to the motor itself to increase hp)
3. the amount of raw horsepower that's needed for a 5mph top end gain let's say 70-75mph is conciderable...

The problem with the above is that it doesn't add up. First two are believed to be almost zero and doesn't match the 3rd.
It seems to me that first 2 cannot justify the speed gain numbers that are mentioned up here.
I feel like we are missin' out on something here...

My .02

[Banana Shark Dave]

Ok BeyondHelp doesn't want to take up my offer of a all expenses paid Demo that's his choice.

However I am happy to open this offer( not all expenses paid) to anyone else currently on this thread.

So here's the deal we go to the fuel station, which is on the way out of the harbour and fill to the top. We go out and test the set up as is, we both take a turn driving.

We return to the marina, where there is electric and the boat stays in the water and we swap the FW over for the stock FW.

I am so confident ( I've done hundreds of test runs with different props at different levels of modification) I am happy to run the stock test without refuelling, so the boat will be lighter. Or We can refuel, testers choice.

Again we return to the same test area ( I have an area I use that has bouys to run between and also can follow same track on gps), we both drive and the results are compared.

I am also happy to demo props with stock blades and only hub modifactions.

I am also happy to change the running order if the "Tester" wants me to.

Just to be clear though the FW is approx 4kg lighter than stock and the Bravo 1 and Rev4 props are just over 1kg with just hub work or just over 2 kg with blade and hub work.

I cannot be fairer than that. Everyone can argue all they like over this and that.

But at the end of the day, what actually happens is the only thing that matters!!!!

You can all argue why, it happens afterwards!!!!!!

[2jz]

Thanks for all your facts and findings. Its clear you both dont have an optimax motor but im sure you know of someone that knows someone that you guys can take dave up on his offer.

Im speaking on my facts with my twin 225 optimax motors with lightened flywheel. Everything dave has said i agree 110% im VERY happy with my two lions nowlol.

Dave plz backup your offer to beyondhelp with youtube video its only fair we can see his expression