Took the Allison out today with my 28 hoss the gearcase is a 2.1 ratio motor is a 225 promax with light flywheel and A6 ecu stock porting with a good tune and it ran 104mph but accelerated real good same set up as the Allison ralle just never carry a gps,seems to be done around 8 grand motor height is even with the pad 4 inch setback next I am gonna try a old offshore 30 it definitely needs more prop for top end for the lower ports...Old promax runs good for what they are...
xr 2002 SPEED TODAY
- Thread starter racerx
- Start date
patches
Well-Known Member
You need a 1.87 case with that 30
procomp
Active Member
So 16 amp electronics with an A6 260 hp fuel curve?
Stock fuel pump set up?
Stock fuel pump set up?
Dave Hensley
Well-Known Member
Would expect better from an old, short driver.......!
michael j giesler
Active Member
ouch and you forgot slower than Bill ha ha
Jeff you need to switch to 1.87's think about all the gas you would save that's alot of beer
pro comp I sat in the boat with a lap top plugged into it to adjust per condition each cylinder from Bill Gohr and it was amazing how better and better it got,yes its a 16amp flywheel if I would of takin the Allison hole shot plate off it would of hit 105mph,i adjusted to more fuel on my 4 button tester and it picked up 2mph by going up one number,it liked more fuel up top kinda fun playin with it for speeds.The boat spun 8500 rpm but didn't go any faster then at 8100rpm...
Dave Hensley
Well-Known Member
Tell us more about the laptop. What software were you using and how were you interfacing the motor? Or were you watching XXX websites while you were just sitting there in the drivers seat?
suicidealli
Well-Known Member
Dave Hensley
Well-Known Member
A King William only item or is it available to us mere mortals? I will have to try it. My XR still has the lounge seats in it......
That ought to get the job done! I love my 28
before season is over would like to try a cleaver with motor up a bit higher, Tyner had great speeds with his on his xr I was guessing 105mph when I ran it yesterday and was not far off boat drove straight as an arrow even with the side steer...
Tim Bostic
Active Member
Running a 28" Triton with 2:1 gears is like running a 26" with 1.87:1 gears....... Great acceleration but would run out of prop on top end..... That's why you can spin it more rpm & not gain any more speed.
For some great top end numbers...... I'd run 1.87 gears & a 30 or 32 Hoss Triton!!!!! Maybe raise the propshaft slightly above bottom?
For some great top end numbers...... I'd run 1.87 gears & a 30 or 32 Hoss Triton!!!!! Maybe raise the propshaft slightly above bottom?
Tim my next prop I am gonna try is a old offshore 30 mercury prop with the same setup and see what it can do,not big into high speeds but just seeing how the pro max does with a big prop,will change gear case over the winter to a 1.87 just never get around to it.Boat has a great punch with the Hoss 28 on it,my SS Allison would average 104mph with a 260 and a 25 pitch prop so the max will give it a good run on the xr..
Tim Bostic
Active Member
The older offshores were good running props for top end...... problem with holeshot being slow & blades were very thin. They were designed for the in-line motors, not V6!
It should give you some good top end numbers, especially when you change over to the other gear set!
Too me, the 225PM motor is one of the best engines Merc made.... The one I have ('99 model) is truly an amazing engine and the last 1/2" of throttle is cool !!!!!!!!
I need to get the XTB21 out and spend a day testing & see what I can get out of it? I've just never had it over 85 mph ....... getting older & just cruise around the lake at 30-35 mph!!!!! ...... Running that slow all the time bothers me because I feel like I'm wearing out a GREAT engine!!!! I should replace it with a 150 & "save" that ProMax!!!!
BP1
Active Member
Shrimpfest jeff?