Vantage XT/Merc 2.5 Setup

Hi Randy,

First I would like to say thanks for your time. I have a 20' Hydrostream with the XT bottom. I am looking for the right set up to get top end speed out of this hull. Currently it has a 97 model 2.5 carb motor,stock with low water and 10 in setback. I am wanting to put a v6 looper 183 ci motor on the boat and have access to one. Would the larger C.I. motor handle this heavier hull better? I am looking for at least 88 to 90 mph, The boat ran 88.6 with a excel Yamaha with a previous owner and the same jack plate. What is this hull capable of speed wise? The Hull is actually an 1987 model Vantage XT (same as voyager XT). Thanks Again for your time...

Chuck and Katrena:

 This boat sounds like one I sold back then.  Its not white with blue stripes?  I assume the 97 carb is a 200 horsepower model and not hi performance 2.5, as I think 94 or 95 was the last year for 2.5 carb hi performance motors.  If it is the race engine it would be faster than the 183 will ever be and we just need to work on set up.

 If it is the 200, here goesthe performance between the 2.5 200 and the 183 OMC is very similar, the set up is different, but the result about the same.  Weve found that the closer to 6 in. 7 in. of set back on an XT that you are, the faster it goes.  At 10 in. as your bow goes up your motor goes down and then you have to jack up higher.  We found this compromise was not as effective as running the prop shaft about 1 in. below at 6 in. 7 in. back.  No matter what anybody says, gearcase drag is not as important as balance and boat drag.  Weve run over 100 mph with the gearcase under the bottom so dont let that bother you. The OMC will have to run closer to the hull (less set back) because it is heavier.  Remember balance is very important, it determines prop type and therefore, over all performance.  A good 200 Merc can get the Vegas to the upper 80s but the Vantage is slightly heavier.  Do you have a trolling motor and batteries on it?  If so, the speed will be in the 70s with just about any motor.  Take the trolling motor and the batteries off and 80s are possible.  I would think the boat was very empty to run 80 with the Yamaha.  Do I think the Evinrude is an advantage?  No, its just different.  Id work on the current set up and see if it has been maximized yet.  We would need to know prop, rpm, engine height, etc. to get closer.  Hope this gets you thinking.

 

Please submit whatever questions you have to IHRTechTalk@yahoo.com.  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Thanks,
Mark C.

[ Home l About I.H.R. l History l Models l Registry l Members' Pictures l Feature Article l Tech Talk ]
[ Literature l Events l Top Guns l Guest Boat l Classifieds l Video Gallery l Racing Corner ]
[ Prop Slippage Program l Animated Videos l Screen Savers l HIN Decoder l Links l Contact Mark ]