Re: HP losses from Bravo 1X drive
 

Which weight/Type Alisyn do you use in your gear case?

Re: HP losses from Bravo 1X drive
 

Rage,
I just checked my oil, and my mechanic recently switched me over to AMSOIL, another good synthetic. I am using their 80W90 gear oil. Athough they rate the viscosity at 80/90, when you move the container, it acts more like a 20/30W oil.
I think they've probably (Timken) bearing tested it to what a petroleum based 80/90W oil would do, but managed to do it at a lower (true?) viscosity, reducing heat and friction in the drive. Just my theory, I'm not a chemist. All I know is it works!
Regards,
Steve
ps great web site www.amsoil.com

Re: HP losses from Bravo 1X drive
 

You say you just checked your oil which i assume to mean the Amsoil 80/90W and the wear/magnet debris was low like the Alisyn gear lube?

Which Amsoil do you use in you motor? Change interval?

Regards,

Bill

Re: HP losses from Bravo 1X drive
 

I have succesfully used and offer a correct cryo treatment followed by proper surface treatment/polishing process that greatly extends the life of these gears. My lower gears were junk after 10-20 hours of casual use and 15-20 wot passes before, with this new treatment I ran them twice as long and 35 plus equally hard passes and they still look like new with virtually no wear. Next season I am going to experiment with thinner gear oil and see how long they actually last before failure. My boat is a good test bed for them with 950 plus ft lbs of tq,Smitty

Re: HP losses from Bravo 1X drive
 

Bill:
I'm using Amsoil 20W50 synthetic in the motor now. I have also used RP 20W50 this past season with good results.
I change all my fluids (drive/engine/supercharger) and oil filter @ 25 hrs.
Checking my oil meant the extra oil I keep in the garage :D !
The motor comes out tomorrow for the winter buildup.
Steve

Re: HP losses from Bravo 1X drive
 

Smitty,
Looks good. We may be talking soon.
Regards,
Steve

Re: HP losses from Bravo 1X drive
 

Do you perform oil analysis when you change oil?

Is PR Redline oil?

Bill

Re: HP losses from Bravo 1X drive
 

Steve,

Which of the Amsoil 20W50 oils did you use?
TRO Series 2000 Racing Oil
MCW Motorcycle Oil
AMO High Performance Oil

Re: HP losses from Bravo 1X drive
 

Steve, after you get your engine back together why don't you drive down and let's put it on the dyno. I'd be happy to do it on a weekend. I can even tweak the ECM. Just get an 02 bung welded in your headers while it's apart. You're no further away than "Rage" is. He came down a couple of weeks ago. Sure would be nice to know exactly what power you've got.

Bob

Re: HP losses from Bravo 1X drive
 

Some pictures from the day.

Re: HP losses from Bravo 1X drive
 

More from the day.

Re: HP losses from Bravo 1X drive
 

Last one.

Re: HP losses from Bravo 1X drive
 

WOW, really cool pictures. I've never seen it from the outside since I'm always in the boat. Great pictures. Can you email me those pictures. I'd love to put them on the web site if you don't mind.

Bob

Re: HP losses from Bravo 1X drive
 

You bet. I will send all of them by seperate PM and use what you want. It is a cool looking test. Really need a video with sound for the full effect.

Bill

Re: HP losses from Bravo 1X drive
 

Bob,
The motor is out. Thank you for the invitation. I really wish I had done before and after dyno runs. We are putting an 02 bung in and Eric will be using his 02 meter to fine tune the fuel curve. I may take you up on your offer this spring!
BTW, I like that L&S dyno.
Happy New Year,
Steve

Re: HP losses from Bravo 1X drive
 

Bill,
Great looking boat. Have you had a chance to run it yet?
Regards,
Steve

Re: HP losses from Bravo 1X drive
 

Bill,
RP is my contraction for Royal Purple, which I think is great stuff (and it matches my boat:D ).
I have never done the analysis thing.
Regards,
Steve

Re: HP losses from Bravo 1X drive
 

Rage

I would think the propshaft dyno would load it harder than a prop would ?

How much HP will it go up too?

A video would be pretty cool!!!!

Rob:drink:

Re: HP losses from Bravo 1X drive
 

Strip, those photos are at my shop when we dyno'd Rage's boat.
It is rated to 800 PSHP. The most I've measured is 588 though. You are correct about it loading the drive pretty hard. Basically you open the throttle all the way and the dyno loads it to the predetermined RPM. So, far a few seconds you are at WOT at 4000 RPM and the boat is not moving! The problem is the drive is gear reduced. So if the engine is turning peak torque at say 4500 RPM, then the prop shaft is turning 3000 RPM, but has the torque multiplied by 1.5. A 400 ft. lb. engine would be making 600 ft. lb. at 3000 RPM at the prop. To the dyno it's like measuring a big diesel engine. All the dyno measures is torque. I won't be dynoing any supercharged big blocks at the prop:eek:

Re: HP losses from Bravo 1X drive
 

Steve,

Thanks, we like it a lot. It is perfect for our type of boating that includes a lot of wake boarding and tubing. Yes I ran it all this season and it runs sweet. However the dyno test showed me it is not yet at its full potential so the work continues. Of course the work never ends.

Regards,

Bill

Re: HP losses from Bravo 1X drive
 

I bet its a good tuneing aid,Can you control the dyno from the drivers seat while ya hitting the sticks ?

Re: HP losses from Bravo 1X drive
 

It's all controlled with a lap top. I just set the lap top in the drivers seat, open the throttles until it loads solidly and press record. The computer takes over and makes the sweep based on the input parameters. The only trick is to be ready to pull the throttles back when it hits the max rpm. That's what I'm doing in the picture where you can see my bald head leaning ove the seat.LOL.

Re: HP losses from Bravo 1X drive
 

Does the blue plate touch the cav plate ? or what keeps it from turning?

Re: HP losses from Bravo 1X drive
 

Yes, that is the torque arm. It has pads on it that seat against the cav plate. To use it on the engine stand I have an adapter that slides into the bell housing with a stop on it for that plate. So all I do is slide the absorber onto the prop shaft or the engine stand and set the proper gear ratio for the application.

Re: HP losses from Bravo 1X drive
 

Bob,
Eric Betty (EB Marine) has secured dyno services for us here in Nashville at one of the racing oriented machine shops at a reasonable rate, so we will be able to dyno my motor before we install it in the Heat.
I'll let you know how it goes on the Nordic forum.
I think it will make it much easier to prop the boat with this data in hand. Your situation this past summer comes to mind.
I may have been overwinding my old setup........
Regards,
Steve

Re: HP losses from Bravo 1X drive
 

Cool set up.Thanks for the info:drink:

Re: HP losses from Bravo 1X drive
 

Here are some numbers to stir things up. I just dyno'd a Whipple charged 383 on the prop shaft dyno. On the engine dyno it made 555 HP at 5800 RPM. Guess what it made at the prop shaft???? 490 The only difference was that the boat has Gibson mufflers. They aren't supposed to cost any HP, but even if they do that's a 65 HP loss running through a Bravo X drive. Interestingly the percentage loss increased with RPM. At 3600 it shows a 10% loss. More like 12% at 5800. So, on a 300 HP engine a Bravo does cost about 30 HP, but double that and the loss goes up proportionally. I'll be testing some other engine packages this winter so I'll post more results.

Re: HP losses from Bravo 1X drive
 

But was the engine dynoed with all the marine asy's and marine exhaust?Was the 490 hp at the same 5800rpm?
Would of been nice to take the muffs off then back up test

Cool info thanks for sharing
Rob:drink:

Re: HP losses from Bravo 1X drive
 

Engine dyno was totally rigged and wet exhaust. Didn't have the power steering belt on. I would have liked to test without the mufflers but they are through bolted and sealed with 5200, so they're not coming off. I've tested them before and not seen any power loss, as is the claim from Gibson also.

Re: HP losses from Bravo 1X drive
 

so where ya think the extra 30 hp went?

Re: HP losses from Bravo 1X drive
 

The P/S pump probably accounted for 5 maybe 10 HP. I believe the drive losses are greater than what people thnik. The more power/rpm the more the loss, more of a percentage than a linear amount. It's possible the mufflers are costing a few HP, but that's the best I can offer at this point in time. I've tested 3-4 engines at the prop and the power was a good 50-60 HP less than what they should have been making at the flywheel. But, I didn't have the opportunity to put them on the engine dyno. I've got a couple of projects this winter that I should be able to do more comparisons. I'll keep everyone posted.

Re: HP losses from Bravo 1X drive
 

You have to be careful when comparing 2 "different" dynos. Both have their own calibrations and +/- percentage errors at different rpm points (electronic load cell dynos use filtering and averaging). When you use a different dyno for each one, you double the possible error factor. A dyno is a good comparison tool when using the same one, same conditions, etc. You also have to be keep in mind the drive load isn't completely the same, no propshaft thrust load, and the temp of the drive cases and oil are not the same either.
A majority of the losses in the drive are from windage and normal bearing friction which will change with rpm. Since windage losses generally increase with rpm, torque loss will go up with rpm, so a drives hp loss at 5200rpm will not be the same at 5800 rpm with the same engine hp at each. The higher rpm engine will have substantially more hp loss through the drive (more torque loss and more rpm), if the drive ratio doesn't change. Also, if using manual calculations, make sure the proper rpms are used for the propshaft if measuring propshaft torque. If you are using engine rpm and calculating propshaft rpm, even a small error (1.50 vs 1.49 ratio) can affect the hp numbers when trying to do this type of comparison.

Re: HP losses from Bravo 1X drive
 

Falcon glad to see you back:D

I would think that outdrive oil temp and weight oil would have a effect on it.

Re: HP losses from Bravo 1X drive
 

BOBL,

This is great information. Not many people have the ability to perform crankshaft/propshaft side by side comparisons using the same dyno. Also, I appreciate you sharing your experience with the Gibson mufflers. I have them on my boat and have always wondered what real-world losses are.

What gear lube was in the drive? I use Merc's Hi Performance but used Alisyn in the past, that allowed the prop to spin much easier. Also, I'm running a Bravo XR and wondered if you have experience measuring one of these. I've been told its losses are greater than the Bravo X.

Re: HP losses from Bravo 1X drive
 

Falcon, keep in mind this test was with the same dyno, same location. I mount the absorber on the prop shaft or engine stand, whichever I'm testing.

Escape, the drive had Merc lube. I've not tested an XR but will the first oportunity I get.

Re: HP losses from Bravo 1X drive
 

Bobl it would be nice to make a adaptor to insert in to the back of the motor like a engine alinment tool that would hook up to your Dyno,Then do a back to back test with the drive vs no drive :drink:

Re: HP losses from Bravo 1X drive
 

Strip Poker,

Your wish has already been granted. That in fact is the exact setup that BobL uses because that is the the way his dynamometer was designed to begin with. Dual purpose. The same identical torque transducer/water brake either attaches to the motor crank or the prop shaft and the computer does the rest.

Re: HP losses from Bravo 1X drive
 

I think what Strip is trying to say is a method to test the flywheel hp IN THE BOAT. Then you could tell exactly what the drive was costing. I believe the exaust routing in some boats (like Rage's Nordic) costs more power since it makes 2 sharp turns after the water mixes with the exhaust.

Re: HP losses from Bravo 1X drive
 

It sounds like it's a good setup. I think the biggest challenge would be to prove the accuracy of the dyno at 2 different torque/rpm points. Dyno accuracy varies slightly at different rpm's and torque numbers because of filtering of the load cell. If you would look at the raw output of the electronic signal it would be varying with every cylinder pulse and vibration, they try to filter and average this out. This is still interesting and would be a good tool if you were trying to compare different drives and/or changes to them (gear lube, oil level, temp) as long as you kept all of the variables withing reason. Also, how close is this to the max torque rating of the dyno (raw torque at the propshaft is probably over 750 ft.lbs)?
Exhaust silencing on a naturally aspirated engine will almost always have some negative effect, but on a boosted engine can be less of a problem.
It will be interesting to hear more results and see how consistent the numbers are.

Re: HP losses from Bravo 1X drive
 

yeap. if there was some way to make a shaft that went thru the gimble ring bolting up where the out drive bolts up? may be more touble than its worth.The info is still fun to tickle the brain:D