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

[2jz]

http://youtu.be/a8QL-RDauDo

[2jz]

http://youtu.be/rGL9Y2t7G2I

[beyondhelp]

Originally Posted by Paul E

What industry do you work in again, and what exactly do you do?

Engine tuner/ecu mapping apparently...

[steve h]

Taken from 1993 quicksilver performance,
but hey do you believe everything merc tell you?

[Toffy]

Hi all, I gave this some more constructive thought.

I'm still wondering why you would see speed/rpm gain with a lighter flywheel, although theoretically it is simply impossible. (yes it truly is theoretically impossible and I hope we are past this point by now )

1/ I allready came up with the idea standard heavy flywheels are not as balanced and would eat a bit power resulting in higher friction and heatloss in the bearings. I honestly don't believe this myself this would be significant or even noticeable. I'm gonna leave it at that.
2/ Could it be this is actually about conditions ? I have no doubt in the rough you can reach higher speeds as the engine accelerates quicker with light FW.
3/ Could it be this is actually about handling ? Would you be able to handle a boat with a LW flywheel better and therefore reach a higher top speed ? To be honest I would have expected it the other way around. A heavy flywheel has a higher gyro effect keeping the engine more in balance compared to a lighter flywheel. Although also for this I don't think it's al that noticeable.

@All. Can you think of any other reason we are not thinking of that would allow you to go faster with a lighter flywheel ?

@Dave, do you think in your before and after testing you have maxed out the boat in top speed, or were you fighting handling or condition issues which would influence your top speed measurements ?

Greets, T.

[Renegade]

Originally Posted by Banana Shark Dave

In effect I will have closed the prop off so the exhaust gases can only escape through the nozzle. Not unlike the jet engines on some passenger airplanes.

Goal;
I am hoping to be able to totally remove the very heavy Exhaust tube on Bravo 1's, High 5's and Rev4's. I am hoping this will force the gases out faster by constricting the exit, a bit like squeezing the end of a hose to squirt water further. This should stop the gases from aerating the blades. Also to get some directional thrust and steering from the gases possibly allowing faster cornering or may be the skeg to be made smaller and reducing drag.

Right.......

[Banana Shark Dave]

2JZ great Videos and some awesome work, keep it up and please post some more video's!!!!

Toffy I have over 20 props mate, when I first changed my FW it quickly became apparent that all previous test data was now no use.

I respeed tested everything, if I cannot complete a test because of weather or some other issues. I simply retest on another day, I would never accept results until I had got the best I could get out of something.

Also where I am based in the solent, because of the IOW sheltering the sea there, there is always somewhere you can test. However I only do acceleration tests in one place because I have sunk my own bouys on a very tight rope.

So tight they just disappear on top of a spring tide.

I am still offering 28 day MONEY BACK on 3.0 & 3.2l Optimax FW's excluding shipping costs, so give one ago Toffy!!!!

I picked up a Mercury Racing Lab Finished Bravo 1 prop today, I have noticed that. Mercury thin the rear hub wall down, just not as thin as I do!!!
Mercury also Shorten the exhaust, however I fine tune mine to customers boats!!!
Mercury leave the big chunks of metal that hold the prop during casting, I remove those!!
Mercury don't thin the front hub walls, I do!!!
Mercury don't polish the insides as I do.
Mercurys Racings Lab finished prop is a improvement on stock and is about 1.4-1.5kg lighter than stock however mine are 2-2.1kg lighter than stock!!!!!!

[Paul E]

Speed tests are useless unless conditions are IDENTICAL, there are so many variables and inaccuracies!

[Toffy]

Originally Posted by Banana Shark Dave

I am still offering 28 day MONEY BACK on 3.0 & 3.2l Optimax FW's excluding shipping costs, so give one ago Toffy!!!!

I'm running a Yammie which I keep stock for now. If I ever go that way I'd allready buy a LW flywheel for acceleration improvement only.
I'd also ask more info on how you make it that light without weakening it too much. But I guess your LW flywheels allready prooved themselves. Don't forget the weight reduction is of secondary importance, it's more important where you get it. The further out on the diameter, the better. Simply because flywheel energy is proportional to it's weight, and proportional to the diameter squared !

Anyhow, good luck with your sales. I'll ask a Merc friend of mine if he's interested.

[Banana Shark Dave]

Toffy if there is ever anything I can help with just ask by PM and I'll do my best.

The weight is primarily removed from the outside edge of the widest part excluding the ring gear. However to remove as much weight as I have, you have to take it from all over in order to keep a safe minimum thickness of metal. Which I have done and you have so rightly pointed out.

I have made them considerably lighter than I sell them, however you need a huge safety margin and mine are already at least 2kg lighter than any others currently for sale. So the weights offered are as light as I am prepared to make them.

Don't Forget I Lighten the hubs on all through Hub Exhaust props.

My Bravo 1 and Rev4 props are currently 2.1kg lighter than the stock weight of 6.8kg. This weight is mixture of metal removed from the front and rear hubs as well as the blades. This also gives a huge acceleration gain and provided you are Slightly over Pitched you will gain an extra 300rpm easily!!!!!!

So combined with the Lightened and Balanced FW you lose over 6.1kg off the weight your engine has to overcome before it starts doing its job of pushing you forwards!!!!!! It doesn't take an idiot to realise this makes a Huge Difference to your Acccleration and Top Speed!!!!!!!

Still what do I know, other than I've lost count of how many of these dual set ups I've supplied now!!!!

I've had reports back of people gaining over 600rpm from stock after fitting both items.

I also offer a 28 day 1 Free exchange on my props, if you decide after testing you want a 24 instead of a 26 or you want a Rev4 instead of a Bravo 1. I do a Free swap (excluding postage), if you have damaged the prop I will still do the swap as long as no one else repairs the prop( I charge the same or less than anyone else) and charge for repairing the damage. If you want to do a 3rd swap I charge £25 to cover polishing and rebalancing and after that it's a £50 trade in charge.
I always have at least 20 props from 19-30 pitch both 3/4 blades mainly on Flo Torque 2 hub kits but also some 15spline props as well.

I have several stock versions of my fully Race prepared props on the same pitch so you can really see the difference they make!!! There's over 300rpm difference between my stock PowerTech 26 4 blade over and thru hub exhaust prop and it's fully Race Prepared Brother, it doesn't just go faster and accelerate faster, it handles better at speed, come and try it for yourself!!!!!

I have a bravo 1 22 pitch stock and fully Race Ready as well as a Rev4 21 stock and Race Ready!!!

So if you want a Really Special Prop, I can make it!!!!

[andymac]

Originally Posted by Banana Shark Dave

Beyond Help

The amount of Exhaust gases that come out of a 3.2l v6 engine being forced out of a nozzle 36mm wide are considerable!!!!

Just seeing the effects on tick over and revving upto 2000rpm (guardian won't allow it to Rev higher) is amazing!!!!!

Dave, surely the big hole in the prop is to get rid of gases. I just wonder why race mids have open exhausts? Don't think it's just to make them sound nice, think there maybe something more to it than that. Just my opinion tho.

[Andy B]

I've read this thread from the start!
Well most of it, I fazed out a couple of times

Dave
What you have managed to achieve with you modification is a more efficient Engine.
This is why you are able to turn a taller prop with the performance gains you claim.
You haven't gained any extra HP.

Beyondhelp
As always your science is spot on, but I think the point your are trying to make is being missed.

The engine is not producing any extra horse power by being fitted with a light weight fly wheel, but the engine (Dave's engine in this case) is using the available power more efficiently

[Andy B]

I think Newton's laws on motion might have something to say on this.


An object will remain stationary until an outside force greater than the"mass" of the object acts apon it.

Lets simplify this down to round numbers.
(Here's the simplified numbers not fact )

If we say that it requires 10% of the engines available power to turn the flywheel and 100% to reach it's Max rpm.
Then if you reduce the Mass of the fly wheel by 2% then it will only require 8% of the available power to move it and 80% to reach it's Max rpm, leaving a power reserve of 20% unused.

No extra power has been produced but this more efficient use of the available power can be put to use to give better performance......


Now I know this is a grossly over simplified explanation and it's late, so i'l probably read this in the morning and say WTF.....lol
But hey i'l get over it

[Captain Chaos]

Originally Posted by Andy B

this is a grossly over simplified explanation and it's late, so i'l probably read this in the morning and say WTF

Almost Certainly!

[Andy B]

...

Originally Posted by captain chaos

almost certainly!

[beyondhelp]

Originally Posted by Andy B

I think Newton's laws on motion might have something to say on this.


An object will remain stationary until an outside force greater than the"mass" of the object acts apon it.

Lets simplify this down to round numbers.
(Here's the simplified numbers not fact )

If we say that it requires 10% of the engines available power to turn the flywheel and 100% to reach it's Max rpm.
Then if you reduce the Mass of the fly wheel by 2% then it will only require 8% of the available power to move it and 80% to reach it's Max rpm, leaving a power reserve of 20% unused.

No extra power has been produced but this more efficient use of the available power can be put to use to give better performance......

Only applies for acceleration. Try doing the same maths whilst the flywheel has reached max speed and you will see no energy is required.

[Andy B]

Originally Posted by beyondhelp

Only applies for acceleration.

But isn't this one of the performance improvements that Dave is claiming?

The improved top end is a result of being able to spin a taller prop with the more efficient use of the available power.

I see no reason for Dave's claims to be untrue. but the confusion between "more power" and a "more efficient use of power" could do with clarification.

I have a passing interest in Dave's boat as I'm a life long friend of the guy who built it.
In fact I was moored up in stokes bay a few weeks back enjoying a flask of coffee and a good book when I heard/saw Dave racing up and down the Solent.
Sounded and look fantastic if not a little to frantic for me!

And knowing the pedigree of that hull design, any improvements made will be noticed I'm sure.

Bottom line
If you are looking for a performance upgrade, then the money back if you're not completely satisfied deal that Dave's offering seems a no brainer.

Now the long term mechanical effects on the engine of running a low inertia flywheel is an argument for another day!

[Marinautic]

Originally Posted by Andy B

I'm a life long friend of the guy who built it.

Kev is a top bloke.

[beyondhelp]

Originally Posted by Andy B

But isn't this one of the performance improvements that Dave is claiming?

The improved top end is a result of being able to spin a taller prop with the more efficient use of the available power.

The available power is the same EXCEPT for whilst accelerating. During this time (which is not very long time) power would be used to also spin the flywheel. Lets put this in context. Imagine running the engine on muffs, and hitting full throttle whilst out of the water... How long would it take before you hit the rev limiter? Not much at all... So you can see that the flywheel and light weight ones really don't play a big part in this.

I see no reason for Dave's claims to be untrue.

Laws of physics are a pretty fundamental reason imho..

I don't care for anything other than accuracy with claims. Top speed being one of them.

[Andy B]

Originally Posted by beyondhelp

Lets put this in context. Imagine running the engine on muffs, and hitting full throttle whilst out of the water... How long would it take before you hit the rev limiter? Not much at all... So you can see that the flywheel and light weight ones really don't play a big part in this.

Now that statement has little or no relevance to the discussion!

It's like revving an engine in neutral and then comparing the results with pulling away in gear!

The laws of physic's are a very big wall to stand behind, but it in no way takes into account of all the variables that exist in an uncontrolled environment like a boat on water....

Lets face it you might as well stand on the end of a jetty shouting a wizard did it.....lol

Bottom line is that Dave is saying that his modification will show an improvement in performance and if you are not satisfied then he'd give you a stock FW and your money back with now argument!

There's a saying that goes. "If it sound stupid, but it works, then it's not stupid"