HPDI and VMAX

[Slippy]

whats the difference between them?

[PSM207]

The H-P-D-I is the High Pressure Direct Injection fuel system. THe Vmax series has the improved lower unit design for optimum performance. The HPDI is available as only an HPDI, or as an HPDI with the Vmax lower unit (HPDI-Vmax). Simply put, the HPDI Vmax has optimum fueling and the optimum lower unit. Where as an HPDI only, will have just optimum fueling.

[Slippy]

so is the hpdi a lesser Motor as far as performance? do they have the same specs as far as performance (top end speed)?

[PSM207]

The Vmax provides optimum top end performance, due to the lower unit design. Are considering a new engine? If so, what hp?

[Slippy]

i have the hpdi right now with a vmax lower unit. great motor, just curious.

[PSM207]

Heck, you've got the best of both.

[21XDC]

I have the best of both...

[spider1]

Now Mike how in the world could that litlle 3.1 liter gas sucker be the best at anything??
I have the best of both! The HPDI and a TITUS lower!
Fuel milage and Speed baby!

[21XDC]

most hp per cubic inch and weight and best yamaha stock gearcase.

[spider1]

More horse power per cubic inch?
How fast are you running?
And do you get over 5.5 mpg?

[21XDC]

How much slower is your 300 HPDI than a 300X Merc? 8-10 mph.... I say that your motor has 275 hp max.... I have 255... Your extra 20 hp is lost with the 45 extra pounds of weight. By the way... I run 85+ in my rig.... Thats about what a racing Merc 250 runs on my identical boat.... I think I'm doing quite well thank you... Now how fast is your Stroker again? The HPDI lower unit was worth 3 mph on my motor.... I love not blowing out anymore. I think I do get that gas milage, Or close to it.

[BuzzB8]

[PSM207]

Is this going to be hijacked or what?

[21XDC]

YES!

[PSM207]

Mike, at times you crack me up!

[spider1]

Mike not even 8- 10 mph! It is more like 5 - 6 and that is with my boat loaded down and theres lightly loaded at best and the biggest problem is that I can not turn the props up to the higher rpms with a limiter of only 6150. It is not the horse power that is killing me but the gears an limiter. The mercury would still be faster but not by a hole lot. Nasty has that hopped up Simons motor and it is still 3 mph slower then some of the X motors so go figure!!!!! Nasty was running 99 in the heat that I was running 96 in and he had half the load!
Most of the stroker guys with the 300x run low 100's with the exception of a few that are over 105.
I would just love it if you could be running your boat up to 90!! That would be great!!!!!
You better check you gas milage I bet it is closer to 3 then 6!!

And 96 with a loaded down boat is not bad I don't think!!!! And now with the cool weather maybe a little more.

[STROKEDYAMAHA]

Cant we all get along J/k ...... V-maxs I believe they are all 20inch shaft motors...hpdi is the high pressure direct injection fuel injection system used on on some (newer)v-maxs.....Spider has the 3.3 300 vmax hpdi.... Mike has the 3.1 efi 066 fuel injection system V-max ....Spider, Mike I do wish they made a 1.65 gear for our lowers that would help the Yamahas get the high top ends that the Merc. racing divison motors obtain.....Hydrotec is the answer to not having a Yamaha racing divison...Mike I think your hp numbers are very close estmates .....Humm wonder what a 3.1 bottom half with 3.3 front half 066 injection with hydrotec tuner, heads big bore throttle body with a blueprint and port.......basicly what Merc does on their racing divison would run? I heard somethings in the works

[21XDC]

Spider and I get along much better than you guys think... I just sent his wife some flowers and chocolate. Conner and I are a lil' bit alike.... I'm just better looking.

I have talked to GE about the 1.62 gears on the yamaha. I think it can be done if someone takes the interest.

[spider1]

BETTER LOOKING! I scrub up pretty dang good!! And evey body know that a Coon Azz looks better then any old yankee!!!

Thanks for the chocolate!! Me and the wife had a great time with it after it melted!

[21XDC]