CignificantOther

Anyone running # 6 Drives on a non-stepped Top Gun?

Which prop rotation works the best on a side by side engine application, inward or outward?

What is the best "x" dimension or installation height of the drives?

GLH

Call Phil he will surely know or call this gentelmen and ask.

http://adcache.boattraderonline.com/6/9/4/59104394.htm

Rice Hauler

I think that if you contact Primal Instinct.
He's Running big power and 6's on a Straight Bottom and might be able to help you out with your questions.
Good Luck,
Rice Hauler

Biggus

Also PM Blonde Cig Chick, she owned the 94 Top Gun 'Ruckus' with 900's and Number Six drives.

Kurt

Primal Instinct

I found turning props "in" improved speed and made the boat really come alive. Didn't really notice any problems around the docks, which is a common concern. Recommend starting with the props turning out to get used to the setup and get a reference point, then switch them in.

I am running a pretty aggressive x right now and am going to try a 1" spacer this spring to see what effect that has on speed and most important to me, rough water handling.

Many things go towards determining the correct x, weight distribution (ie cabin or cover girl) , notch or no notch (pre '90) , etc...

Don't be surprised if everyone you ask for advice will give you a different answer!!! Probably the best advice that I received was put it a bit high, cause you can always use spacers (max 3") to come down. Trying to go back up means new motor mounts, tail pipes, etc....when I was asking around, I was advised to put the bullet anywhere from 2" above the bottom to 3" below...I went high on mine ('99 notch, 950's, no steps, cover girl, side by side).

Too high and it will be hard to come on plane and you will lose the ability to trim the nose up. Too low and the boat will just wallow...

It's a lot of coin and work, but #6's ROCK in the rough stuff!!!

Good luck!

CignificantOther

Thanks for all the input. Primal, do you have any use for 2" spacers? I think I also need 1" spacers.

This is a 1990 Kevlar Top Gun with a full cabin(sofas, bath, vberth) and a notched transom. Approx. 925HP each. Presently, the props are turning inward with 2" spacers installed.

The boat wants to porpoise with any little trim below 65 MPH. I think the drives are too deep for # 6's.

What is a reasonable height for the needle in relation to a straight edge on the bottom of the boat intersecting the needle with the drive set level?

I will have to measure, but I think the needle is now about 1 1/2 - 1 3/4 inches below the running surface. I have no planing problems with the drives tucked.

Thanks,
Steve

Primal Instinct

Steve,

I don't think I will have any need for 2" spacers. The 1" spacer may even be a bit too much.

With your setup, it sounds like you will be right on the money going without the spacer...that would put the bullet 1/2" or so above the bottom. That sounds about right with a full cabin.

An idea might be to try different props to see if they can hold the nose up and help minimize the porpose. You could call Matt at Throttle Up and see if he has any ideas. I have read on OSO about TG 38's with full cabins with problems porposing. Luckly I haven't had much problem with that, but that may be due to the covergirl cabin and less weight up front. I normally cruise with neutral tab and drives slightly tucked in.

Curt

Jeffrey

Ask DMAN (Devilman). He spent over a month and countless outings "dialing in" his '99 with #6's and 1000's. It runs like a bat out hell, straight as an arrow, and extremely well balanced. I don't know specifics except that his props turn inwards.

CignificantOther

Thanks for the other #6 Gun owners info.

Curt, I measured my drives and needle is currently 1 1/8 to 1 1/4 inches below hull surface. Completely removing the spacers will put me at approx. 3/4 inch or more above the running surface. What are your thoughts on planing difficulties with 4 blade 17.5 diameter props?

Where is your drive height now and what sort of GPS figures are you seeing?

Thanks,
Steve

Primal Instinct

Steve,

I am 2" above and ran 17.5" props last summer and didn't have any problems coming on plane. I also tried 18" diameter props last year and they had a bit more bite. So I now have a set of 17.75" that I am going to try this spring. I was running 94.5 gps last summer and never really got a chance to dial it in.

DMan was big help and was very generous in sharing his experience in dialing in his TG.

From everyone I have spoken to and from personal experience, I would definitely give a shot at running with the "needle" 3/4 above the bottom. When I test the 1" spacer, I will be 1" above bottom with covergirl cabin, so a bit less weight up front...

Curt