How much power would it take to make a 28 cig run 80mph?
 

I want to upgrade the power in my boat but would like to stick with the small blocks. It has the merc trannies and trs drives. How much power do you think it will take to crack the 80 mph barrier? Thanks.

Re: How much power would it take to make a 28 cig run 80mph?
 

I'm guessing 400+hp per side.

Re: How much power would it take to make a 28 cig run 80mph?
 

450 hp to 475 hp, if it is a TRS boat, 27" Mirage props, about 4900 - 5000 rpm, if the drives aren't way deep; however, since you arte going small blocks, 25" Mirage 5300 rpm. My father had a 27' Magnum that ran an honest 84-85 mph (27" Mirage props spinning 5200 rpms - labbed with added cup) in the final years of ownership, but it the beginning it ran 81 mph on radar. That is how I am coming up with your numbers.

Re: How much power would it take to make a 28 cig run 80mph?
 

I don't think you will likely get to 80 MPH as rigged. Why? Because the HP required to offset the stock TRS drive height would be significant...maybe 500+. If you were (not sure it is possible) to raise the TRS drive height to accommodate an ideal drive height for say the Bravo 1 props, your engine height will exceed the clearance of your current engine compartment.
Even if your re-rigged the boat, you would now be on the reliability edge for the TRS drives and past the edge of the Merc transmissions. If you break a Merc tranny, finding parts may be a challenge.
Numerous high HP small block 28' Cigs and Magnums were raced in the '80's and few were able to exceed 80 MPH.
If you are still not deterred, consider switching to Bravo drives and a total re-rig including drive and engine height, new exhaust and engine hatches.
Oh...don't forget the bottom work on the hull. If you get to 80 MPH, you won't like the handling of the boat.

Re: How much power would it take to make a 28 cig run 80mph?
 

As usual, never a simple answer to a simple question. The first two posts did sound a little more promising though. Thanks for the replies. I'll have to mull this over.......

Re: How much power would it take to make a 28 cig run 80mph?
 

You're not going to do it with the Merc trannies. Listen to BenPerfected, Bravo's are the way to go. But you are limited with small blocks, and big blocks put a lot of weight in the back affecting handling and causing porpoising. Good luck with whatever you end up doing.

Re: How much power would it take to make a 28 cig run 80mph?
 

I will qualify my response a little further, the Magnum had the bottom blue-printed, and the X-dimension was raised. Hp was estimated, the boat had big-blocks, never porpoised at cruising speed, transmissions never failed in 19 years of ownership, broke a prop shaft once (a TRS boat). That is fact, not BS. The bottom of a 28' SS and a 27' Magnum are the same. There were three 27' Magnums in Barnegat Bay, NJ in the 70's running better than 80 mph (all had big blocks).

Benperfected's response of 500 hp per engine is probably more realistic, than 450-475 estimate, I gave you, unless you really dial it in, with props, drive height, bottom work, ect.

Re: How much power would it take to make a 28 cig run 80mph?
 

500+ per side at least, I run a 30 Panther scarab TRS's with 450+ a side and only see 73mph somewhat comparable. what Ben Perfercted said is probably the most honest answer you will hear. I think he has a fast 30' boat and somewhat a similar hull.

Re: How much power would it take to make a 28 cig run 80mph?
 

Back in the 70's my best friend and I converted a 27 Mag & a 28 Cig from Volvo to TRS. He had the cig, and also some $$. As a result he had some small bocks built that dynoed at 400 HP each (which was a lot back then !!) We put the engines on 29" centers and ground into the rub rail area to get the drives a high as possible. It wold run right at 80 anytime you wanted. My Mag would never run over 70. I hated him :) They were both balanced perfectly.

Today I would do it with small blocks and Bravo's. There is a 28 in Steve Lopez's shop with 6.2's that he just re-rigged, I believe it runs 80.

I also think big blocks are too much weight for that boat. The 1 big block Magnum in Chicago never did run very well.

Re: How much power would it take to make a 28 cig run 80mph?
 

Sounds like raising the drives is mandatory. I want to stay with the small blocks. How did the various magnums and cigs that you all are talking about handle at speed. Were they controlable or all over the place.. Would hate to go through the work and have the boat be too squirrely at top end.

Re: How much power would it take to make a 28 cig run 80mph?
 

Follow up question. How would I come up with the ultimate x dimension for this boat if I want to keep the trs drives?

Re: How much power would it take to make a 28 cig run 80mph?
 

Mandatory: hydraulic helm and external steering. That made the boat handle a ton better, reduced chine walk considerably. In dead falt water it wanted to chine walk at 80 mph, but at 84-86 thew chine dance went away and it wanted to porpoise a bit in dead flat water, but the porpoise was no big deal, you wanted that in order to break the bottom loose and reduce wetted surface area. Once we crossed some boat wakes, or waves in the Ocean the porpoising stopped and the bottom worked great. We raced alot boats in the ocean off Margate and Atlantic City in the first 10 to 15 years of ownership, the boat handled great, that big-block stuff is BS regarding handling at varied water conditions at 85 mph the boat flew level, we smoked the small blocks - 28' SS's, period, in any water, not even close, but with todays stroker small blocks, and the fact that you have a set of them stick with the sbc. I like the Bill Mitchell small block crate motors, if repowering is an option, though I do not have first hand experience with them. My father had big-blocks, and bought his Magnum without power. We looked to get into at least one race, on most days two or three over the course of 19 years with 12+ weekends of boating per season we raced alot of people (some repeat runs against the same boats), the point is I had the seat time, and my father more so than me had the seat time (it was his boat), so I am not blowing smoke up your @ss. That 28 SS will need to be driven, and need seat time to get comfortable with it. There was a 28 SS with 475 hp motors (on the dyno with tube headers, P-1000 exhauts in the boat),it did not run 80 mph (if on same radar gun that radared us at 81 in the early 90's - the Barnegat Bay radar shoot-out), but he did not have it all sorted out. If you get it all sorted out (props, bottom, ect) the boat will be alot of fun, but you will need to learn how to drive it, it is not a point, trim and go boat, like some of these boats today. We have a 34' Phantom now, and now I realize the newer design step bottom boats of today (with a semi-pad), handle nothing like that straight-V I had been in for so many years.

Drive height, take it to the rub-rail or higher with the TRS drives, what centers are the motors? Our Magnum had 32" centers, which killed us for an aftermarket exhaust system that would fit, have tube length and not be restrictive. Small-blocks should not have the same issue, that we had. If you go Bravo, the are a shorter leg compared to a TRS, I have no advice on X-dimension, with a Bravo set-up.

The 28 SS was my favorite boat when I was a kid, and the 27' Magnum was right there too. It will just take time and money to get that boat to run 80 mph.

If you questions with set-up/technical, and handling speak with my father - Alan Jones: 856-589-1070, he is much more techically (engine and drive expertise) proficient than me.

Re: How much power would it take to make a 28 cig run 80mph?
 

The bottom work is not a big deal. My experience has been that you just need remove any hook and lengthen the inner strakes, maybe 6-12" past the CG. You can then go back and remove some length if you want more bow lift. The bottom work is only a few thousand...a drop in the bucket compared to the re-rig, engine build, drives, hatches, steering, etc.

Re: How much power would it take to make a 28 cig run 80mph?
 

Check out :
http://www.go-fast.com/boat_speed_predictions.htm

If you know what you have now, this calculator will do a good job of telling you what you'll need. Since it bases the final calc off what you have now, everything should already be taken into account (hual design, x-dim, etc.)

I've been playing with this based on a bunch of dyno tested buildups and it's seems amazingly spot on as long as you have a baseline.

The site also has a calculator for prop selection. I ran a bunch of similar boats with different props through this and it seemed to work out well.

Re: How much power would it take to make a 28 cig run 80mph?
 

keep the TRS transom assy, put konrad shorties on, that will raise the X as well as build reliability. build a lil more power and you will see 80. its not to tough to ring it out of a cig.
its even easier on a lighter hull.

Re: How much power would it take to make a 28 cig run 80mph?
 

A buddy of mine has a 1976 28ss with true 400HP (dyno'd) engines. it has the mercII trannies and TRS drives.....on its best day we hit 67mph on lake michigan...he has hit 70 in the ocean in Miami once....the boat has not been modified hull wise at all since it came from the factory....so the setup is not "dialed in"
And i've personally seen a 28ss that had 500efi's with prochargers and extension box's and the owner said the engines were doing 650hp ea and the boat was in the low 90's!

Re: How much power would it take to make a 28 cig run 80mph?
 

One of my boats is a 1973 magnum sport-2 years ago it had 11 1/2 to 1 small blocks with merc trans 2 and trs-the x height on the trs was into the rub rail-after blowin up numerous transmissions I had rerigged with 406 bravos-standard x height on a bravo ( and I am going off of memory)is approx somewhere around 14 1/2 ".I set my x height to 18 inches with my 406 small blocks and it runs well over 80 all day long-needless to say I need 4 blade props to get it goin-those motors are for sale if you want them-just put together some dart 434 small blocks.cause im feelin the need for more speed.never had a problem with trs however if you are puttin a boat together with those merc trans 2 trannies your crazy-parts are hard to get and if you build a big small block it probably wont have alot of vacuum at idle because of the cam and if you shift those trannies over about 600 rpm's they wont take it FOR LONG

Cig 28 that was here on the chesapeake ran 75 with 450hp small blocks, trans?? and stock TRS setup. It went up for sale maybe two years ago, and is now ???? First Cigarette I ever saw that had separations of webbing/stringers to hull issues - must have been run guden hard!!:)

Hello J-Bonz,

Who's Exhaust Manifolds are on that 28 SS?

Thank you

Jim

I had a 1978 28SS with 280HP/350s, Merc 1 trans., TRS drives. She ran 60mph on her best day spinning 21p cleavers. During the 4 years we owned her I did a few mods to the engines, cams intakes, ignition. Maybe the engines made 325HP each. We ran 21p Turbo Vectors and 21p Mirages with max engine rpm @5200. The best we saw was 60 on the GPS. Tried those old cleavers and got 63mph at 5300+rpm.
Boy that boat drank gas but she was/is a wave crusher.
Anyway, I have spoken to many, many people about the 28' Cig including racers from back in the day.
IMO, twin BBC in a 28ss is a no no unless you want a boat that will have like 6" of freeboard.
I did know of a 28SS that had 500+HP BBC and TRS drives that vary fast for its time, early 80s, but man every time they lowered her in with the fork truck she looked like she was going to sink.
A fellow that used to race them told me that the best setup they ever had was with some screaming 6000rpm 400cube small blocks, 1.5gear TRS drives, 25p Mirage props. That boat went some were around 80...
To answer the question, my guess is that with the TRS drives it's going to take 500HP+ per side to hit 80. If she was rerigged with Bravos, maybe 450HP each.

Biggus has a friend with a 28SS who dropped in a pair of GM ZZ383 crate motors rated at 425 hp each. First report he was very pleased with the engines and said it really woke the boat up. No notes on speed increase though. Haven't heard any more about it since.

Hey Iggy what up man! Actually it was not a 28 Cig that wwe dropped the ZZ383's into, it was a 26 Sutphen. The boat picked up 15 mph!!! Now runs a solid 80.
The ZZ383's have been fantastic, now have 250 hrs on them. Zero trouble.

Kurt

28ss BBC
 

I have a 1978 28 ss with a pair of closed cooled 454 mpi engines. merctrans trs drives. 27mirage props. As stated above it has almost no free board in fact when I leave it slipped up at the marina. People call to say it is sinking. I Have not had enough run time in the boat to get a gps on it myself. But the guy I bought it from said it does 74mph on gps saltwater. I have run against another boat that is know to do 68 69 and I can pull away from him if that helps. Also Judging by the way it pulls your cheeks back it feels like it is over 70. I will be sure to get a gps on it this summer. Brian

Not sure, I found it online. But, I do believe it is a friend's of mine cig. I will try to get a hold of him.
Jr.

Thats a nice looking 28 Brian! You should think about towing it to Naples for the Sebago Lake Poker Run ithe end of July.

Did you find a MercTrans? Audiofn has one if you are still looking.

Kurt

When is the Poker Run. I would like to get up there. I have three spares now but I may be interested in another. Brian