JaniH

Dont you think the merc intake was a restriction? 5600rpm sounds low for 240/245 duration cam, makes me wonder if it was the Rons milder 230/235 114lsa. Still have the dyno sheet?

articfriends

iTrader: (1)

Yes, the runner length of 14/15" dictates hp peak on these restricted intake engines, even with intake mods, You can add more and more cam on them and gain nothing, just shifts tq peak to a higher rpm with less overall torque. Modding the runner length and cutting dividers gets them to carry about 200 rpms higher. With your tunnel ram Id expect that cam to easily pull to 6000. IF your dynoing it, would be interesting for you to install a adjustable timing chain and cover that allows you to easily access it and move cam timing around on the dyno and see where your tq vs hp peak goes then make a decision of which ones more important to you.
FWIW, the guy with the modded 509 w that cam ran 84 in a 280 PQ at LOTO shoot out on day one and 85 on day two (after tearing all the interior out of cockpit and putting it in back of his truck on saturday night)! think that was 3 years ago. We saw 78/79 on local river when checking/touching up the tune before he tried multiple props.

JaniH

Testing the cam timing at dyno has been in my mind, just trying to find cost effective 2pc timing cover, those Fancy comp cams covers costs the same than my custom billet cam. I ones had a cheap speemaster 2pc cover, and the fitment was not that bad, i quess they dont make it anymore.

JaniH

That pq280 seems to be fast hull, is it true 28ft hull?

articfriends

iTrader: (1)

There a stepped hull, Ive heard that steve Stepp or something to do with Velocity had input on that 280 PQ hull. I bought a stock one a couple years ago w stock 502 as a quick flip/plus used it to fully develop a 60 lbs injector tune for mefi3 on 100% stock boat, it ran 67/68 gps after bottom was cleaned and was running perfect. Most those 26/27/28 ft boats will barely break 60 gps w stock 502 mags.
Another customer had one and another 509 I dynoed and tuned with promax heads made around 610 on a glory pull and around 580 with marine exhaust and water in exhaust, that boat ran 81/82 at shoout a year or 2 before the other one I mentioned

Brad Christy

Jani,

I have an '02. I think it runs really well for the power you give it. Mine has the 496HO with the Whipple stage 2 tune and an M1 ProCharger. Procharger advertises this kit at 615HP. Opinions vary as to what it actually puts out; some suggesting as low as 500. I turn a Bravo1 28P prop, and we run 76-77GPS, maybe 78 on a perfect day, and it will still pull my fat ass out on a slalom. It climbs on plane with little more than 3K RPM, cruises at 30-35MPH at about that same RPM. I think there's more in it (mine) with a more efficient (labbed) prop, but I don't think I can pull a 30P with a happy engine. I've seen videos of them running 85 or so, but I have no idea what power was in it. They run clean and stable at that speed. I think the hull is actually spec'd at 27'6", including swim platform.

Thanks. Brad.

JaniH

Sounds good! I am trying to get my old 26ft stinger above 70mph. Really like the ride of the old stinger, the only problem is porpoising at wot. Mine is with raised 17.5 x-dimension, and also jumps to plane. Those stepped hulls are in different level for sure.

JaniH

Confirmed the dome volume from JE tech support, for the 0.079" dome height what is left after machine work. JE confirmed that it is approx 7.48cc instead of 6cc that was my own calculation. This gets me 10 to 1 compression. I repeat approximately 7.48cc 🤣🤣🤣. I got the answear in 1 hour, gotta love Je tech support 👌

articfriends

iTrader: (1)

The one video thats out there of racin jason at loto running 85 on sunday at shootout i think 3 years was the MPI 509 engine I dynoed and tuned that made 620/620 here. The announcer calls it a velocity in the video because he had a velocity the year before or something.

articfriends

iTrader: (1)

You can always put it down .100 in hole and seal it then cc the difference too if in doubt