speed w/heavier outdrive oil
 

After using merc high perf drive oil,super secret max worx drive oil,various synthetic 80/90 gl5 outdrive oils and still chewing up lower bravo gears to the point they were junk at 40-50 hours,I started using 85/140 royal purple gear lube in my drive. From what I know the second/bigger number is the viscosity index at operating temp,i think api rates at 180 deg farenheit. No problems from the heavier oil like lack of oil circulation because its too thick or anything BUT-would 140 weight drive oil slow a boat down a noticable amount? Has anyone went from 80/90 to 75 or 85/140 and lost a measurable amount of speed? I would think its possible but looking for anyones personal experience. I rember reading about don garlits taking cover right off rear end in the sixtys and running just on the film left on the gears and making a final pass in heads up racing looking for a thousandths of a second. I'm thinking the 140 weight oil is going to cushion the gears better on my boat and keep a oil boundry between the teeth to prevent chipping,galling,etc. I'm also missing sime speed on top end compared to earlier this year but I have added a stellings box and have had very few clean runs to see what boat really runs,thanks for any input,Smitty

Re: speed w/heavier outdrive oil
 

Smitty, I forgot to ask you what drive lube you are running while up at Boyne. Have you ever tried Red Line Shockproof Heavy? Some of what it says on the lable is: "At high temperatures and under extreme pressure, this lubricant has a film thickness greater than an SAE 250, yet the power robbing drag in the gear case is very low comparable to a 90wt. The ability of this lubericant to resist throw-off helps reduce gear noise and help prevent tooth breakage."

I use Red Line....it IS some pretty sticky stuff.

Re: speed w/heavier outdrive oil
 

in the race cars, the viscosity of the lubes was critical to speed and we would use the lowest viscosities that we could POSSIBLY get away with... for shorter races we would use a 0 weight gear oil... but on boats with all the monstrous drag numbers from other sources i wouldn't think you would see a significant degradation in speed if anything measureable at all...

the motors would be different... heavy oils in the motor will consume some power that you simply never get back but in the gbox in a marine condition, i wouldn't worry about it... run the oil that keeps your hardware alive...

having said that... i tested every red line product in back to back, real world conditions extensively against all others ( in the race cars...not boats) and found them to be decidedly second rate... from a wear and protection standpoint, convention petroleoum oils often gave superior service life and performance a lot of times. it would never occur to me to use any of their stuff in any hardware that i was reponsible for. for me , with the single exception of some hybrid lubes made a company called NEO synthetics, the mobile 1 pure synthetics were, across the board superior in all respects and i could buy them essentially anywhere without all the magic bean hype and pricing of the royal purple. i suspect the royal purple is pretty good stuff and it is popular down here... but there is mobile 1 in all my stuff... but having said that my stuff is all pretty conservative ( bravo 1's , 425 hp map mpi) so i don't have anything like the unit loading issues you do...

im sure i will get hate mail from the amsoil guys...

Re: speed w/heavier outdrive oil
 

I won't knock anyone's choice of lube but I know I gained 100+ rpms switching to amsoil from the merc oil in my bravo 3's on a formula 330SS with twin 330's. I had recent drive work performed (broke a vertical shaft due to my stupidity, not the drive oil) and my mechanic put the merc stuff back in. Lost about 150 rpms at WOT from what I remembered. Part of this may be due to summer weather now that its 90+ every day. It was Jan 1 when I changed the lube with amsoil. But in January there was a noticable difference between the morning run with merc and the evening run with amsoil. I changed to amsoil 10-40 in the engine the following weekend and tuned the engine and noticed no further difference in rpms, but did observe the oil pressure was rock steady and decreased much less at idle after a WOT run. I'm sold on the amsoil gear lube.

Re: speed w/heavier outdrive oil
 

I went from merc hp to redline heavy shockproof and felt that I lost about 100rpm, I have no doubt that the Redline is the ultimate gear lube, it's messy and takes 24 hours to drain. The magnet was pretty much clean on the second redline change.

I couldn't get any the last time I pulled to outdrive to change out the top seal. So I went with M-1 75-90. There is no doubt that I picked up just under 100rpm, The oil changes can be done in an hour.

Had considered running their 140 weight, but am pleased with the way the oil looks and the minimum amount on the magnet.

600HP + Bravo-1 230 hours.

Re: speed w/heavier outdrive oil
 

Changed oil in drive again this weekend,no metal whatsoever,between the 140 weight and heat treated gears seems to be working real good. Boat is a solid 2 miles per hour slower than before installing the ext box and going to the thicker oil though but is turning same exact rpm's so I blame it on the box,Smitty

Re: speed w/heavier outdrive oil
 

Smitty, did you also put on a -2" shorty lower? Mine seems to be 2-3 mph faster now with them. Good to hear about the gears. Keep us updated. Ian

Re: speed w/heavier outdrive oil
 

I just switched to amsoil marine gear lube 2 weeks ago from Merc. green stuff.. I cant say 100% but I believe I gained about 1mph or so, and it seems to shift easier..

Re: speed w/heavier outdrive oil
 

Just a stellings ext box in the plus 1" position,going to add a 1" drive spacer next to try to get boat back to where it used to be. Can't move box to the neutral position without pulling motor and everything else plus I would have problems with my bilge plug,it would be 1/2 under the box. Glad I didn't buy a shortie housing as this doesn't want to work well,I can only imagine the problems that would cause,Smitty

Re: speed w/heavier outdrive oil
 

I think Amsoil makes a great product for most applications but if you are sending mega HP and Torque through a Bravo nothing is gonna save the day it would seem.

I personally think a Bravo can handle 500 HP and remain durable..that's about it in my books..

Re: speed w/heavier outdrive oil
 

I'm running 900 plus hp/ft lbs tq thru a single bravo max worx upgraded drive,the upper has 200 plus hours on it (the gears),I have been thru it every 40-50 hours checking for damage and changing bearings because metal from the lower scarred them slightly. Now it hasn't always had that much power put thru it either,the first 130 hours was 750 hp and this is only a 27 ft boat so rough water and no wake zones at cruising speed or idle account for alot of the hours too. The lower gears are a experiment for durability,they are a set of USED gears I bought and had re-heat treated,they have over 20 hours on them now,trying to see what its going to take to get them to live (other than reducing the power). I broke them in on royal purple 80/90 and been running royal purple 85/140,I'm NOT a die-hard royal purple fan by no means,I just can get it locally wholesale (cheap in other words) so its what I'm using in this experiment. I have drained it a couple times in past weeks including changing it out from the 80/90 and I'm not seeing ANY metal in the oil yet,usually by 20 hours (on lower gears) I'm getting a serious amount of metal in the oil changing it every 6-10 hours (every weekend if I see some full boost hard 2-10 minute runs),every other weekend if I only do short wfo burst. Either the thicker oil is helping to cushion the gears and keep them from galling or deeper case hardening is keeping gears from breaking thru hardness or both. I'm not going to switch back to thinner oil just to see if its the oil either as I don't want to buy bearings,gears etc plus breakdown but I am going to tear lower down pretty soon and see how the gears are looking,Smitty

Re: speed w/heavier outdrive oil
 

XR upper gear pics-200 plus hours with 750 and 940 hp blower motor turning them.

Re: speed w/heavier outdrive oil
 

Looks like alot of us will be getting gears treated this winter. Maybe we are on the verge of a beak through in longevity here. :evilb:

Re: speed w/heavier outdrive oil
 

I sorta expected the gears to catastrophicly blow the teeth off the first time I put the boat into boost but it hasn't happened yet and I'm starting to gouge on it pretty hard the last few times out,we'll see how the gears look in a few weeks,especially after a weekend at hardy pond. I have chewed up 4 different sets of lower gears in past couple of years so it won't just be a fluke if they hold up. I specifically used lower gears that were already used in another boat because I didn't want to wreck a brand new set if they were just going to crumble from being brittle or something from deeper case hardening,if they hold up a full season and still look good then I will call this a sucsess, Smitty

Re: speed w/heavier outdrive oil
 

I hope I didn't give you the wrong impression on the xr upper gears but they are just the ones max worxs sells with there upgrade parts,they are holding up with no special treatment other than the bearings,tower and cap they use,blowing uppers apart has never been a issue on my boat. They could be re- heat treated too but you would have to remove the brass parts for the cone clutch somehow,Smitty

Re: speed w/heavier outdrive oil
 

Smitty,

I am not too concerned about the uppers. They seem to be able to hold up. At least, better than the lowers. I not running near the power you are. 680 hp, 660 torque. I ate up a set of lowers last season in 17 hours. However, I think they were just set up wrong. This winter, I set up new gears, bearings, etc, in the drive myself ( well, with help over the phone from Mr Gadgets ). So far, approaching 40 hours of pretty hard running with no issues and clean oil. If I can get the season out of them, I would be happy enough. BUT, if this process works, maybe I can get 2 or 3 years from a set of gears. That would be great. My only concern is the fact that you have to have a slightly used set of gears treated. That complicates things. If thats the way to do it, I guess I will have to get a new set of gears and set them up just before the end of the season to get a few hours on them.
Actually, I am in the market for a -2 Imco lower. I would love to test it out. Hopefully, 1 will surface before the end of the season.

Vinny

Re: speed w/heavier outdrive oil
 

Vinny,I started out with used gears in case they self destructed the first time I leaned on it but I also thought it might be a good idea to use ones that had a little run time on them too. After they were re-heatreated you couldn't tell they were used though. They went on shafts pretty tight too but the max worx shafts I used have always fit tight anyways. I think the heat treating would work on new ones too but I'm slightly concerned if they had no wear whatsoever on internal splines they might not fit,Smitty