38 Top Gun 1990
 

Hello all,
I am new here, I have bought a 38 Top Gun 1990, with a pair of 525SC and konrad drives.

I am redoing all the structures becauses the boat was in england and in france before, and now here in the caribean, and the different seas was very rough, so it needed some work....I will post the pics soon.

I have a few questions for you all if you can help me?

Today max speed is 70 mph with hydromotive P5X 25p

What will be the mph gain if I change the pulley of the compressor (now is a 3.5 and i want to buy the 3.05")

And for next project what power/prop if I want to go to 85mph with her?

Franck.

Welcome - what RPM are you seeing the 70mph at?

Can't help you on the blower question.

You'll need big power to go 85 in a flat bottomed Full Cabin Top Gun. I'd guess 800 to see it consistently, but that is just a guess. Some of the other guys who have actually done it can probably help you better....

Thank you,

I can see 5100 rpm at 70.

That's what i presume also, but I just want to know if someone done it before me (I guess yes.....)

And for the blower I am also very curious to know if someone done it also, and if there is no issues (less reliability or...?)

I'm running 750's and run low 80's at 5800 labbed 30's.

And its LOUD!!!

According to the Bam speed calculator you need 1500 hp to hit 85mph. I have a buddy with a 94. Topgun with 600sc's and it will run 81-82 but it is a Bravo boat and it won't do it every day. Also you should be looking for at least 5200 rpms. I would a run a 4 blade prop to either 24's or better yet labbed 26's.

I have a pair of 26 BRAVO, When i am in water, I will test it and see to send them for a lab finishig, but the P5X is great in big water!!! (but I can also feel that the 5 blades are hard to turn for my engines....)

thank you for the bam calculator, i went to the page, it's a great tool!!!

So in fact 800 hp engines will do it!!!, now I have to choose the engine......I like the potter 777, and it seems that there is no need to modify the hatch.....I have to work hard to buy them in 1 or 2 years.....

I'm just going to throw this out there, but instead of sinking 50k into a set of engines, you could just sell your boat, take the 50k, buy a Twin Step boat with a set of reliable Merc 575's and run 85 all day long without the liability of bigger engines behind you. Financially this would be MUCH smarter - dumping big money into a flatbottom is money you will realize pennies on the dollar for versus a T/S CIG where you could run it and maintain it for a few years and just lose a few thousand hopefully.....

realize pennies on the dollar for versus a T/S CIG where you could run it and maintain it for a few years and just lose a few thousand hopefully.....[/QUOTE]

You are FU KNEE GUY!

Just a FEW G's I wish!!

You are FU KNEE GUY!

Just a FEW G's I wish!![/QUOTE]

Im laughing my ass of right now Scott! you have that TS at Vincents yet?

Not yet. Back at the boat house.
Can we say ANOTHER few G's

You are FU KNEE GUY!

Just a FEW G's I wish!![/QUOTE]

HAHA - realative to the fact that if he drops 40-50k into a flat bottom you will basically get NONE of it back. You at least stand a fighting chance (if there is such a thing) in a T/S.....

I totaly agree with the fact that it wolud be better, but, in fact it is very complicated to have a USboat here in guadeloupe because of the CE certificate. Since 2006, it is very difficult to buy a inboard boat with big V8.
I have a friend of mine who bought an outerlimit 42, pull out the engines and put 3 verados 350 behind it......that's awfull.....

And the Cig I have just bought is an old french boat so CE certificate is ok, and I can put whatever engines I want in.

The other solution is buying a brand new boat (that i can not afford..........) or buying a 525 or 662 merc used boat......

Another thing is that i am redoing and reinforcing all the structures of the boat now, it will be over in december i think, so the boat will be better than a new one, because stronger and stiffer (and heavier also i know.....that's why I want more HP)......

So your friend has the No Discipline Outerlimits??

Yes that's the boat, well, that's not awfull, the guy who have adapted the verados have made a very good work, but for me a boat like this outerlimit or a cigarette or that type of boat is nicer with the inboard, and over that, nothing replace the thunder sound of a compressed V8.......

I believe I sold the drives for that boat. Did you buy it from Francois P ?

Kurt

Yes Biggus it 's this boat, because Francois have bought a DONZI 43ZR.

Good for him. Francois is a very nice guy.

Kurt

You will only gain about 20 hp per engine by changing the top pulleys on the superchargers. You might see a 1-2mph gain or so. You can change the pulleys without any other modifications and it should put the engines at about 7lbs of boost.

The first thing I woud do with that boat is call BBLADES and have him send you some better props for that boat.

From my own experiences and what I have read, you can't be getting enough bow lisft out of those hydromotives.

an go from there.

Good luck with it. Old cigs are great boats.

Thank you that was exactly my question.

Kurt, can you tell me if Konrad make some extension boxes and what are the gain? more speed? more/less handling?

Yes, we do have extension boxes (Konrad ACE package) but gains on your application would be minimal, if any. Installation would also require a pretty comprehensive re-rig.

Best of luck with your new boat! :drink:

Kurt

You're gonna need straight HP and also solid tranny's as well!
I have a 1990...800hp(598ci with baby blowers)...huber 1450's tranny's.. Konrads...and merc 4blade 30's

5300rpm...full tank of fuel...84mph all day long and I haven't even played with the props