311-SR1/How Fast with twin 600's
 

Would like some input here. If I drop a pair of 575 or 600 horsepower motors in Outlaw what do you guys think I would realistically see for speed?

77-79 MPH

Is that all??????????????? I'm getting 68, sometimes 70 now with twin 454 mags....

I was thinking more like low mid 80's. If I'm gonna just get 77/79, that isn't worth the cost.

I think WAGS382 is pretty accurate in his estimate. I ran an '89 311 with 645 H.P./side right at 80 mph. This was with unlabbed 28 bravos @ 5000 rpm so these motors were not dialed in to peak torque/hp ... I didn't want to run them that hard. Consider that while very solid and predictable, the 311 hull is heavy and "old" technology. Although my '99 382 weighs 3000# more than the 311, it runs almost 5 mph faster with the same motors and props @ 5400 rpm. If your boat is in good condition, it may still be worth the $$$ ... there are not to many 80 mph 311's out there and the Cig guys just crap their pants when you go by them!:D

Outlaw,

Just saw you are in Sarasota. With labbed props and salt water, you might get a click or two over 80. Let us know what you decide!

If your boat is in good condition, it may still be worth the $$$ ... there are not to many 80 mph 311's out there and the Cig guys just crap their pants when you go by them!:D [/B][/QUOTE]

That in itself would be worth the money. I'm planning on dropping the silent thunder box and going with an extreme marine tubular platform (if my wife absolutely makes me)(I like the clean look on the back). I know Chief Engines dropped a couple of 750's in a 311 but was never able to get any info on it. I'm planning on talking to Innovation Marine about this, but am also up for suggestions. The boat is in GREAT shape for it's age. I spent a year looking before I grabbed this one.
The original asking price was 47,500 (Nov. 2000) with tailer, and I got it for $ 33,500 then the guy allowed me 3500.00 for my wife's sixteen foot center console fish boat, so I traded that and 30K even. The interior is a solid 9, the exterior a solid 8.5. I'd love to have a Top Gun someday, but that is in the future. For now I'd like to play with this.

There is nothing better than smoking a cig.

I've heard good things about Innovation, but I went with Sterling. They are only one hour from me and are great guys to work with. I know they often ship by truck back and forth to TNT. It would be worth your time to call Mike ... they are not really as expensive as one would think.

I added extra flanges on my platform to lower the water level and also cut out (2) 2" holes in each baffle to reduce any restriction. It sounded wicked but not too loud or annoying. There is another 311 in Monroe, Mich that has a tubular platform on it. It looks good, but without some form of muffling device, I would be worried about noise regulations in the future. The motors you are considering will have a pretty radical sound that you may find overwhelming after awhile, and they will definately attract the attention of enforcement officials.

Red Dog, what exactly do you mean that you added flanged to lower the water level? On my silent thunder, I took those circular holes on the bottom of the box and enlarged them to big honkin' rectangular holes. I worry sometimes if a pelican might try to make a nest up there. I cut the partitions in front of the rectangular exhaust outlets completely out. Made a nice difference in sound and gained 300 rpms on the top end to boot. When the boat comes up on plane and those rectangular holes come up out of the water the noise level increases but not overhwelmingly. Here on the Gulf Coast, we don't get hassled by noise regulations. The VAST majority of performance boats do not run any type of mufflers or silencing systems. I just have never particularly liked the look of integrated/bolt on swim platforms. I just don't like them. I like the clean look like the back of a Cig. I can tolerate the tubular look, because it does not overwhelm. Any feedback on staying with natural aspiration or going supercharged. My gut feeling is staying natural but I am up for suggestions. Some have told me it might ultimately be cheaper just to throw on a set of "chargers" but REALIBILITY is the key ingredient here. Any feedback appreciated.

I raised the location of the stock flanges on the back(stern) of the platform and squeezed in a second set of flanges below them. Basically doubled up the outlet flanges on the tail end of the platform. I kept the plugs in the drain holes to keep a little cooling water in the platform so the fiberglass didn't melt from the heat of the exhaust. It seems that your approach was also very effective in improving performance.

Superchargers are really cool and there is nothing like the blower whine when they spool up. But a good engine builder can obtain very big, very reliable H.P. with natural aspiration. My 510 c.i. Sterlings put out 645 H.P. and over 600 ft/lbs torque with a single carb and a flat tappet cam. Those numbers can be increased to ~675 H.P. with a cam change and the new Crower hydraulic rollers which oil the roller wheels for better longevity and durability than the non-oiled lifters. These numbers would push a 311 to mid 80's and a stepped 382 to about 90 m.p.h. if propped right! That is turn key, no maintenance, and idle very smooth @ 500 r.p.m. in gear.

After two years of nightmares with expensive fuel injection that never worked right, I learned the KISS approach ... keep it simple stupid!

What exhaust are you running? If you are running the Merc cast iron exhaust, you will need to upgrade if you want to optimize engine upgrades. The higher through-hull outlets from the silent thunder platform present some problems which I can caution you about and enlighten you with before you encounter the same.

Can you give me the contact person and number for who did your motors? Thanks for the info. Russ

Mike D'Anniballe at Sterling Performance.
54220 Pontiac Trail
Milford, Michigan 48381
248-684-5040

Please mention that I referred you and let me know if I can assist you in any way.

Chris

419-882-1680

Chris, thanks a lot. I will give him a call, and yourself as well. Russ

I'd think you should get a bit better than 80. My 357 with two 540hp 454s and TRS does 76. Bob's 357 with 650s is supposed to do 83. Just my guess. Let us know what happens. That'll be one bad 311.

I have a '87 311 with 420 Mags with B&M superchargers. I haven't GPS'd it yet, but I am probably hitting somewhere in the mid-80's. My friend has a 382 that GPS's at 76 mph, and I literally blow past him. The speedometer seems reasonably accurate up til 75 mph against my friends 382, and I can bring the needle on the speedo around to about 7 o'clock when flat out.

I actually need some new props, as I am turning about 5600 RPM. I just got the boat last year, so it definitely needs some tweaks. Right now I have 25 pitch Mirages that have been cupped.

Actually, I just quickly looked around here, and it seems that some people have modified their silent thunder platform for better flow. I have to take mine off as the gasket is leaking exhaust, and I am interested if anyone could make some recommendations and had some pictures of what they have done.
Thanks!

Jaybird,
Welcome aboard!! We've discussed this topic almost to death in the past. Do a little search in this forum and you'll find gobs of info on silent thunder platforms from new gaskets to total board rebuilds (I know, I did one:mad: )

I've had the board off my 242 and my 311. Not much we don't know about silent thunder boards,,,,, unfortunately:(

Good luck, it's not that bad of a job.

A friend had a '93 336 with 525's. Changed pulleys and it ran 82 on radar. Stock x dim on Bravos and Mirages right out of the box.

A Vegas guy had a 311 with stellings boxes with twin 980hp blower motors. Claimed he saw a true 100 with it, but it wasn't very rewarding. Somewhere I got a list of specs and pix of it.

These hulls need a little truing, but are good hulls. i have no doubt that with a raised x, boxes, and massaged props that they'll run even better. If I ever get the time, I'll prove it.

As it is, I just have a huge warehouse full of parts to make it happen - and no time to mess with it.

What do you mean by a warehouse full of parts? What are you planning on doing? Thanks....

Oh, not as in retail or store warehouse. I have two 40' semi-trailers full of my junk. I have a 34' enclosed trailer that houses one or two projects worth of junk at any given time. I have a 14x30 rented storage building full of junk. I have a 14 x 40 storage bay in a storage barn full of stuff. I have half of the "attic" of a bike shop full of my junk, and a third of a storage warehouse with bike,car,ski, and boat parts in it.

My extension boxes, superchargers, ignition systems, XR drives, gauges, carbs, intakes, valve covers (and spacers), cams, rockers, springs, lifters, gasket sets, valves, crossovers, stud girdles, pushrods, valley pans, oil pumps, torque plates, windage screens, fluidamprs, timing covers, cam buttons, CMI headers, offshore mounts, knock sensors, and a bunch of other junk is all crammed in the corner of the warehouse.

What am I planning on doing?

Going 95 in a 311, what else?
Just gotta set aside 3 months to do it.

Man does that ever sound cool! What kind of power you planning on to get to that speed? Also, do you think by going to IMCO 2" shorter lower cases would help? I am strongly considering that also, and could you do it without extension boxes? Trying to pick your brain as to ideas because it sounds like you've got a good idea going. Thanks...R

I've got Imco +3 boxes. 12 inches setback and 3 inches up. The rule of thumb is one inch up for twelve inches of setback puts you back to "square one". So height wise 12+3 would give the same "bite" as 2" shorties on the transom. Ext boxes give the drive more leverage on the hull.

Formulas are cut for 3" spacers on center rise BBC manifolds for the silent thunder platform. The Brtavo replacement CMI's I have should work with the engines raised 3 inches.

The 311 hull is a good hull and I'm convinced that with filling and block sanding, sharpening the strakes and rear edges, a 12" setback and 3" up will give me a good baseline to start with.

I'm aiming for 750+hp on pump gas and expect to run 90+ after tweaking.

I don't have cones on my XRs and dont plan on using them until I get a feel for how they act with the above setup.

I have no idea when I will get around to this, since I have been "meaning to" for quite a while now.

Hope you don't mind me asking all these questions but I feel like I've found a "well" of information. So, if you are going to raise the motors three inches, I would suppose that means your CMI's are lacking three inches in "height" to line up with the factory "thru hull" holes. How are you going to raise the engine, some time of motor mount extension?

What are you "filling and block sanding" on the hull? Just normal dings and chips, or something more? Also how sharp are you going to modifiy the strakes, mine are in excellent shape but they are not what I would consider "sharp". How sharp is sharp, if that makes any sense? I've always heard that nose cones really don't make much of a difference until you are above the 80 mph mark. Down here there is a real issue of who makes the best ones, Hydromotive or Bob's Nose Cones. I don't have a clue whose is best. I suppose they are both pretty good. I know by swapping out my original Mirage props for Hydromotive's Quad IV's made a hell of a difference in Outlaw. The IMCO extension boxes sound like a real good way to go. Thanks for all the info. I've printed out everything you've told me and putting it in a "make Outlaw faster" file. Thanks.....

Imco makes a +3 Inner bracket. It has all of the rear mounts raised 3 inches. Then all you gotta do is raise the fronts.

Take a look at your current exhaust manifolds. There is a 3" spacer block between the manifold and the riser. If you remove it and raise the motors, you are still using the same holes in the transom. The CMIs should (I haven't test-fitted them) line up once the motors are raised.

The last 6' or so of hull needs to be FLAT. Shoot some flat black paint lightly across the hull and block sand it with 400 paper on a 2x4 stud. It will show the high and low spots.

rough sand the edges of the strakes and rear edges with 180 and apply marinetex. Sand them as sharp as you can, always using a sanding block. Water will run "around the edge" if it has any radius and act as drag.

As far as cones, it matters a LOT on what your x dim is, and what kind of positive trim you must run. On a straight vee, you always need help lifting the nose for less drag, but deep x creates drag even more. So it's a trade off.

Like anything else, there is no way to know what will work best until you have duplicated a setup and tried all the options. I will definitely try a cone at some point, but not until I have done the box and the motor work cause they will change it all. Whether a cone helps now is useless information later.

I know I've been slowed down on outboards when adding cones.

Cool.....My wife see's this project and my ass is toast. Will get to it asap. That black spray paint on the hull is a killer idea. Then just sand it till it's all white. Duhhhh...
Now far up should I fill and sand the strakes or probably best to just do the entire length. Realistically, how much speed gain do you think this will accomplish over a "stock" rounded edge hull. Just curious. Now I'm really getting excited. There's a particular 35 Cafe Racer I'm kind of gunning for.

No, if you got dips bigger than .020" (and you will) then you got to rough them up and fill them with mtex also.

Only worry about the last 6 feet of hull.

anywhere from 1 to 3 mph.

(I've honestly never done a hull over 20', but have seen excellent results on little outboards. You gotta do these big boogers on your back while the little boats, you just flip them over...)

I can't wait to get started. Gotta think of an answer when the wife asks, "now what the **** are you doing, instead of working on the bathroom"?

You can fill with gel and it will match better, but the edges will be weaker. MTex is tougher than gel.

The white won't be a dead match though. Formula gel is not a pure white.

Fairing compound is easier to sand than MTex and can be used in the open areas, but won't hold up to the edges either. I'm not sure if there is white fairing compound, though, cause the stuff I've used is blueish.

On the outboards, we used blue fairing compound on the flats, Mtex on the edges, and then sprayed 2 part polyurethane over it and wetsanded with 600. Left it that finish. On the rear edges, we actually built "lips" on the tail. What I mean is that instead of sanding to match the transom angle, we built it out 1/2" past the transom, block sanded it square and straight, and then put a reverse 45 bit on a router with a pilot bearing and cut a 45 back towards the transom. Ended up with a trailing edge sorta like a 45 degree knife edge.

Ahaa!!! That is what I pretty much pictured. Can you tint Marine Tex. I've used tha before on feathering in edges from nose cones I installed on my 242. Don't honestly know if it made much of a difference or not, boat only ran mid sixtys anyway. I'll end up using Marine Tex throughout cause I don't want problems down the road. That's an interesting concept what you did at the transom edge. Think I'll try that as well. Thanks. Russ

The lip works well on a light boat, but I'd be a little concerned about getting it broke off coming on and off the forklift (mine stays in dry stack). You'd also have to make sure your trailer was easy on the trailing edge.

We also used the lip on the inside of the left rear sponsons on tunnel vee circle race boats. Turn so hard your vision would go gray.