What we have found during the course of testing and modifying these motors (for this hull) is that you can run larger and higher pitch props , Correct me if im wrong all you hydro nuts out there but I would of thought that you needed a reasonable ammount of torque for this type of hydro as due to hull design a great deal of lift has been taken away,I can quite happily run a higher reving motor in my thunderboat, but as I say hull design has a lot to do with that,We have tried lots of other props one of them being a 6518 and found lots of noise (revs) but not enough go foward.
We will still do a lot more testing yet with motor and props but we are at 70.8mph so far so good progress imo :drinks:

I still say rpm is the answer but then its all about opinions.A good sports hydro should be looking for numbers in the high 70s and more id think,can you get that with a big prop ?.Will it hurt to try the one i suggested.Maybe i got lucky on my t boat as it ran mid 60s the second day out with a stock 6717/3 i didnt try any other props as i was more than happy but im sure a smaller prop would have made her faster as i feel she still had more rpm to find.It seems your progressing but as i said i believe more rpm not torque will = more speed.Its all about opinions i guess sory for giving mine if you dont like it,but there you have it.

a sport hydro in the high 70s and more?are you mad?the props you suggested mart are way too small for what we run and are just a waste of time,maybe you should check your gps as it may be broken,just my opinion,but opinions are just that,what we are getting are results
cheers Mark

No im not mad the whipplash SPORTS hydros consistantly run mid 70s and some have hit 80+,in fact John Finch held the saw record a cpl of years ago with a whip gv of 82 mph not sure if it still holds it .It was a heat racer too not a boat built for saw if memory serves.As for my gps no it works fine ,as i say my old rockett topped out at a tad under 69 mph with pads,without as i first built it it clocked exactly 61.46 mph.There have been a few of these hulls running these speeds and fastest i know of was 69 mph by Matt Gunn.If a T boat can do those speeds then yes i think a sports hydro should be hitting 70+ with a modded zen,rcmk or as you are a QD.Dont call people mad just because you disagree thats just disrespectfull.
Mart
oh seems i am out of date heres his 2009 record 90.652 mph :o

no disrespect intended but i keep hearing about your stuff on someone elses thread,maybe you should start your own
Mark

NEVER MIND ,if you cant take constructive critisism and opinions then maybe you should think twice before posting on a forum ?.

Come on guys...keep it civil! BTW, sport hydros that heat race in the high 70's are very rare, if they exist at all...I mean, run those speeds and finish races... mid 70's is VERY fast for heat racing sport hydro... As for the T-boats, yes they do run close to the same speed as some of the sports (mid-high 60's) simply because they are basically the same bottoms. The T-boats with modded engines that is.. they run about the same as the conventional Sport Hydros. When I say conventional I mean designs that did not trick the past rules by pulling out the sponsons... Anyway, enough said... in my book, if you're running anywhere between high 60's to mid 70's, can drive and can finish the race, you can win it!

Hi marc,
Thanks for your comments, If I can end up with a sport hydro that courses and finishes heats running mid 70s then i will be more than happy with that, like you say you cant win races when you are floating upside down on the back straight :=D
We are working on getting a hydro that is fast but stable and predictable, I will build another motor later for the straight line stuff and am sure we will get more speed.
Hope to get out and do some more testing in the weekend with props etc , will try and get some more video up next week. :drinks:

Oh i have been civil Marc ,Damian im sure you will get into the mid 70s good luck with it.I should have learned a long time ago not to give my opinions but ahh well what do i know,i wont bother in future.

It's all good Mart....was just trying to get the conversation BEFORE it got bad! lol Everyone has a right to their opinion. I was just voicing mine...it's no better or worse than yours. I just personally don't think that high 70's is realistic for sport hydros in heat racing. I attend the US Nationals most every year...the fastest boats and racers are usually there, and I have never seen a Sport hydro in high 70s heat racing... it's good if you see riggers in that range to be honest.