Go Back  Offshoreonly.com > General Discussion > General Boating Discussion
Start to Finish: Building Our 50' Skater >

Start to Finish: Building Our 50' Skater

Notices

Start to Finish: Building Our 50' Skater

Old 01-12-2018, 07:55 PM
  #1571  
Registered
iTrader: (4)
 
Join Date: May 2009
Posts: 1,891
Received 460 Likes on 244 Posts
Default

when and where will you water test

Last edited by outonsafari; 01-12-2018 at 08:53 PM.
outonsafari is offline  
Old 01-12-2018, 10:41 PM
  #1572  
Registered
 
Join Date: Jan 2006
Location: St. Pete Beach, FL
Posts: 3,566
Received 559 Likes on 335 Posts
Default

Originally Posted by 999JAY
Looking very impressive, as apposed to running the two turbos in series "compound" would it not be better to run them in parallel with a programmable switch over valve so one spools up first then the second comes in at a predetermined speed.
This would reduce back pressure and help elevate lag,

The setup looks like its going to be putting on a bit weight with the turbos and overdrive box, have you estimated what this might be? not that it makes that much difference on a 46 endurance machine, better to be a bit heavier and hold together.
That would be my preference. Parallel twins with an actuator exhaust gate. We’ve had some great results in a boat with that setup.
hogie roll is offline  
Old 01-13-2018, 07:41 AM
  #1573  
Registered
 
Join Date: May 2003
Location: UK, Florida
Posts: 421
Likes: 0
Received 54 Likes on 31 Posts
Default

Shame you couldn't have done a parallel setup also it would have been great to see the difference in the torque curve on the dyno between the two.

Do you know if industrial have ever done any back to back test between the two setups.
999JAY is offline  
Old 01-13-2018, 07:51 AM
  #1574  
Registered
 
Join Date: Jan 2006
Location: St. Pete Beach, FL
Posts: 3,566
Received 559 Likes on 335 Posts
Default

Originally Posted by 999JAY
Shame you couldn't have done a parallel setup also it would have been great to see the difference in the torque curve on the dyno between the two.

Do you know if industrial have ever done any back to back test between the two setups.
We reduced the time to plane off on a 70’ sporty from 30ish seconds to around 5. Merritt complained that people were flying off the back of the flybridge and asked us to dial it down a bit.
hogie roll is offline  
Old 01-13-2018, 08:06 AM
  #1575  
Registered
 
boatfreak's Avatar
 
Join Date: Mar 2002
Location: Indy
Posts: 2,807
Received 162 Likes on 63 Posts
Default

Originally Posted by hogie roll
Merritt complained that people were flying off the back of the flybridge and asked us to dial it down a bit.
An early contender for post of the year.
boatfreak is offline  
Old 01-13-2018, 10:15 AM
  #1576  
Registered
 
BigSilverCat's Avatar
 
Join Date: Jan 2003
Location: Joplin, Mo
Posts: 2,630
Received 50 Likes on 12 Posts
Default

We are doing compound turbos instead of doing twin turbos that are in parallel with a bypass valve because we are wanting higher boost pressure along with the quicker spool up time.

Most turbos are designed around having an efficiency range in the 30-40 psi range. If we did parallel twins we could not really run a higher boost, just the ability to spool quicker and have lower exhaust temp at high rpm. But we are wanting a higher hp and the most fuel efficiency we can get. By having the turbos compounded we can run each turbo in its designed boost range and end up with 70-80 lbs of boost to be able to make more total hp and the same hp with less fuel.
BigSilverCat is offline  
Old 01-13-2018, 10:47 AM
  #1577  
Registered
 
BigSilverCat's Avatar
 
Join Date: Jan 2003
Location: Joplin, Mo
Posts: 2,630
Received 50 Likes on 12 Posts
Default

Originally Posted by turbom700
What size are the turbos?
They have tried two or three small turbos and two or three big turbos already, trying to get the best spool up and lowest egt's. Next week there going to try a lot smaller high pressure turbo and a bigger atmosphere charger. There are millions of options of wheel size, ratio combinations, and that goes up by exponent using a compound turbo so they are making drastic changes to narrow down the range they need to look in. And we are not doing the "hey this is what everyone does" mentality. We are trying things that may not work but would not know till we try. Right now they are in the 81 1.15 small charger and 93 1.35 large charger range. Making around 65 PSI at 3800 rpm at 1200 hp and 1200 egt. I want to run a smaller little charger to have the boost gauge move with the throttle. Something like a 63-67 mm It will make the boat more usable when throttling in the rough water.

Here is video of it running on the dyno, the intake tube will be different when its in the boat. The dyno uses a different bellhousing and starter location so the intercooler has to be turned around. In the boat the intake tube will run around the back side of the engine.

Originally Posted by BigSilverCat

Last edited by BigSilverCat; 01-13-2018 at 11:34 AM.
BigSilverCat is offline  
Old 01-14-2018, 06:12 AM
  #1578  
Registered
 
Join Date: May 2003
Location: UK, Florida
Posts: 421
Likes: 0
Received 54 Likes on 31 Posts
Default

If you are looking for boost in that range I would agree compound is the way to go as each charger will give you an efficient compression ratio of around 2-1.
The smaller charger should help low down torque especially if you decide to go with the overdrive gearbox.

How did you get on with the drive ratio, boat seemed to be performing well enough with the 1-1 setup are you still thinking of overdrive?
I would imagine with 1200hp at 3800 rpm and 1-1 ratio you are going to run out of prop options unless you do so, are custom props an option with huge pitch? only down side a big pitch prop isn't as efficient as a smaller prop running higher rpms and the larger pitch prop will certainly need vent tubes to get her on plane.
999JAY is offline  
Old 01-15-2018, 09:35 AM
  #1579  
Registered
 
Join Date: Dec 2013
Location: Minneapolis, Mn
Posts: 358
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by BigSilverCat
They have tried two or three small turbos and two or three big turbos already, trying to get the best spool up and lowest egt's. Next week there going to try a lot smaller high pressure turbo and a bigger atmosphere charger. There are millions of options of wheel size, ratio combinations, and that goes up by exponent using a compound turbo so they are making drastic changes to narrow down the range they need to look in. And we are not doing the "hey this is what everyone does" mentality. We are trying things that may not work but would not know till we try. Right now they are in the 81 1.15 small charger and 93 1.35 large charger range. Making around 65 PSI at 3800 rpm at 1200 hp and 1200 egt. I want to run a smaller little charger to have the boost gauge move with the throttle. Something like a 63-67 mm It will make the boat more usable when throttling in the rough water.

Here is video of it running on the dyno, the intake tube will be different when its in the boat. The dyno uses a different bellhousing and starter location so the intercooler has to be turned around. In the boat the intake tube will run around the back side of the engine.
https://youtu.be/03R2GZO2miQ
I'm a little surprised that at 3800rpm your egt are that high with that large of turbo's(respectively) What's the temp drop across the water to air intercooler? Turbo's seem close to what I would suggest, and your nuts on, on keeping a smaller charger for quick spool then gating around it for high rpm and boost.
turbom700 is offline  
Old 01-15-2018, 12:21 PM
  #1580  
Registered
iTrader: (2)
 
Join Date: Mar 2002
Location: Miami Beach
Posts: 2,142
Received 3 Likes on 2 Posts
Default

Originally Posted by turbom700
I'm a little surprised that at 3800rpm your egt are that high with that large of turbo's(respectively) What's the temp drop across the water to air intercooler? Turbo's seem close to what I would suggest, and your nuts on, on keeping a smaller charger for quick spool then gating around it for high rpm and boost.
funny I thought 1200 was on the low side considering that is WOT. making that much HP. I'm no expert just my initial impression.
pstorti is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.