What exhaust for 311?
 

New 540's are being built. What exuast should I get? I know I need the extra 3" rise to hit the transom holes and dont want to fight with them to line up. Also looking to avoid the big bucks like having CMI custom build a set. What are you guys running on your 311s? Thanks.

Re: What exhaust for 311?
 

ask Formula Outlaw ..... he's got a nice setup .. I just installed some Gil Mainifolds with SM pipes ....I had to have wedges made to hit the holes ...and he had to have some wdges made also ....

Re: What exhaust for 311?
 

I went with EMI Thunder aluminum exhaust and Stainless Marine tips with the internal "SuperFlapper". I had to have a 3 inch spacer made up of aluminum billet that cost me seven hunded bucks so the risers would line up with the holes in the transom. The SS risers have the three inch spacer built in. I went with the aluminum because of the weight savings. If you're running a hot cam, be sure to plumb it so the water enters the pipe as far down as possible. With your setup, I'd go SS.

Too Old at Trick Marine can hook you up with about anything you might want. He's the best....

I couldn't be happier with the results. Here's a couple of pix.

Re: What exhaust for 311?
 

Dustin,

I understand why you would assume this. However, the conclusion is incorrect. I went through this several years ago when upgrading the exhaust on my 311. 3" rise C.M.I. WILL NOT work ... they will not clear the fiberglass rim around the engine hatch area without extensive cutting into structural fiberglass (I had to return the 3" rise I ordered). I used the standard C.M.I.'s, but the angle on the tailpipes was almost horizontal and I had a lot of problems with reversion.

To solve this, I had to trade up to a 382! :D

The 311 and silent thunder does present a problem and I'm still not sure what the best solution is. I had previously ran Gils and had no reversion problems, but they were very tight and everything was a b**** to get to. I also believe Gil is now out of business anyways. You might want to call Bob at Lake Precision Welding in Cleveland ... he did all the welding for Gil and now does Hardin's welding. He made new tailpipes for my 382 that are dry to past the transom so no problems with reversion.

Re: What exhaust for 311?
 

Are your 540's short deck strokers or are they tall decks? Don't forget to allow for increased height and width if they are tall deck blocks.

Re: What exhaust for 311?
 

Give Fred (Too Old) a call. We went through "Exhaust systems 101 for a 311 Formula together". He can set you up. Just tell him what you're doing and he'll take it from there. Best prices anywhere and he has set customer service to a new level. Trust me on this oen. You won't be disappointed.

On the EMI Thunder series, the SS riser which has that three inch spacer included, will line up just about dead perfect with the stock holes in the transom. Fred has access to just about any exhaust system you can think of, but most importantly he'll steer you in the right decision depending on YOUR set up. Call him.

As you know he's an OSO advertiser. "Trick Marine"...Good luck and keep us posted.

Re: What exhaust for 311?
 

http://www.eddiemarine.com/Cart/deta...CategoryID=107

F/O - does this set up negate the need for the custom 3" spacer??

Re: What exhaust for 311?
 

Yes. If you choose the SS risers, the three inch spacer is "built in".

In the older Eddie Marine catelogs, they used to sell a 3 inch spacer for their aluminum risers, but is now a discontinued item. Different reasons were given for the discontuation, I personally think it was intefering with the sales of their SS units. Just my two cents though.

Like I said, I was as interested in reducing weight over the props as anything. We all know how azz heavy our boats are anyway. Between losing the silent thunder box and swapping over from those Mercruiser "anchor" exhaust units, I lost over 500 lbs. My boat now sits close to two inches higher out of the water at the stern. That's like losing two inches on my "X" demension". It certainly made a difference in the way my boat runs. Doesn't "jump" up on plane quite as quickly as it did, but once up there, it accelerates stronger and I gained a solid 4 mph on the top end. (GPS)

Plus it sounds better and I personally like the looks of a clean transom.

Re: What exhaust for 311?
 

Well.......... not quite Outlaw. The "X" dimension is a measurement of the drives to the bottom of the hull. All you did is raise the whole hull out of the water. This does not change the "X". You may be dragging less hull but, you're not dragging less drive. Drive depth relative to the bottom of the boat is unchanged.

Re: What exhaust for 311?
 

Thanks guys! I will call Trickmarine tomorrow.
RedDog, I have short deck blocks and will be on the edge of reversion. Hopefully I can find something that will bolt right in. -Dustin

Re: What exhaust for 311?
 

Bit of a different setup, but replaced the stock merc anchors and risers with Stainless Marine exhaust and risers on my stock 454 mags. Everything bolted right up and I am very pleased with performance gain.

Not sure of MPH gain as went from pilot (old VDO) to GPS speedo.............did Imco nosecones at the same time. Would guess I picked up 4 - 5 MPH between the 2 upgrades.

Had to move up to Mirage 25's from 23's to keep the R's down and now 73 MPH on a good day. :D

Re: What exhaust for 311?
 

I stand corrected you are absolutely right. However, as my hull at the stern is now higher out of the water, so are my drives. The whole "schabang" is nearly two inches higher now. If the hull "came up", the drives, as they are attached to the hull, came up with the hull. (did that make sense????:D)
But you are indeed right, the "X" stayed the same.

What dya expect, I just be a dumb carpenter....:D :D

Re: What exhaust for 311?
 

My EMI's worked fine but they are close. I got the 3" extended SS risers. One side clears fine but the other side barely touches the mirrorplex under the hatch on one riser. Made a small dimple in the mirrorplex but no one sees it but me (my wife says I'm anal - imagine that! :rolleyes: ) If my boat doesn't sell I'm going your route next year Outlaw. Extreme Marine platform and some SS tips. :D

Re: What exhaust for 311?
 

Friend of mine put stainless marine in his 311, I believe he put a 3 in spacer in that he bought directly from stainless marine.

Re: What exhaust for 311?
 

Looks real good...:drink:

Funny, I have a small "dimple" on the port "outside" of my hatch cover too. :D

Re: What exhaust for 311?
 

Yup, me too. I have the EMI stainless risers.

I would also look at Stainless Marine. They make nice stuff. I'm thinking I may go that way next time, and someone else mentioned here using them. However, it is nice that the spacer is built into the riser with EMI. Did not know that it is separate with Stainless Marine. Less parts = less chance for leaks.

Re: What exhaust for 311?
 

Isn't THAT the truth....

I went with the Stainless Marine tips with the internal "SuperFlapper" and it does NOT make any "flapper noise" which I've heard on many other tips with internal flappers. Too Old turned me on to these and could not be happier. :drink: :drink:

Re: What exhaust for 311?
 

Jay, did Gordon have to weld water passages shut in your risers??

Re: What exhaust for 311?
 

I have water jackets in my risers. When I had my 3 inch spacers made up I took a riser as a template. When we went to install (the manifolds were already on with duct tape over the openings to keep moisture out) guess what, no water jackets in the manifolds. After straddling the fence on what do do for about two weeks and asking everybody (yeah, I know, you're all just wincing here) I finally said screw it and bolted the whole thing up. My spacers do get warmer than the risers but not HOT. If it ever got hot enough for steam to form, the steam would follow the easiest way out, up the waterjackets, and out through the risers, etc. I actually probably do get some cooling from the water that does get in there.

All in all I don't think it should be a problem.

Re: What exhaust for 311?
 

He did weld those shut. There was no need for them, and they were leaking from the previous owner's install. Now EMI only sells them w/o water passages, most likely due to all the leaks their customers have experienced.

Are you going to loose your Merc HP robbers :)? If yours are original I'd get rid of them now before they let go and grenade a motor...not worth it, or did you replace those already?

Re: What exhaust for 311?
 

Haven't done yet but am becoming all too aware of what could happen. like a lot of us, my business partner (the Mrs) isn't so excited about spending $4k. I'm working on her.

Re: What exhaust for 311?
 

I had a '92 boat I bought off Lake Winnipoopie with a single 454 mag 365 hp, everything stock. Ran in Newburyport for 3 seasons. Exhaust looked ok on the outside, but I had the motor out to work on the hull, and decided 10 years was enough. Once the exhaust was off, you could see that it was leaking on the inside right into heads! If I had went one more season, BANG! Glad I caught it when I did.

Food for thought, and nightmares (sorry!)

Re: What exhaust for 311?
 

Same thing happened to me on my 242. Took it out once too often and that was that. Rule of thumb: if you can see ANY water leakage on the outside, you can bet it's leaking on the inside. That's why I changed the exhaust on Outlaw when I did. It had just started showing a leak on the outside where the risers bolted to the manifolds. Never even started it once I noticed that. Motors had run find last time I shut'em off and wasnt' about to take the chance.

Re: What exhaust for 311?
 

Same story here, guys. Actually had those NICE plastic water inlet fittings/drains on my Merc manifolds and they were leaking and allowing water to run down on top of the manifold bolts. Bolt heads literally crumbled when I put a socket on them. Decided if I was going to pull the motors to get manifolds off I would go ahead and freshen ( :rolleyes: ) them up at the same time. Upon teardown, one set of heads completely ruined and the others already had the beginnings of water damage. Needless to say the merc anchors went overboard (along with 300+ lbs) and in came the EMI's. Of course, with new EMI's I couldn't just "freshen" the motors. :D :D :D

Re: What exhaust for 311?
 

I am going with the EMI Thunders. CMI wants almost 4000$ per motor to make them fit right. Not worth it to me. I'm will need that money for drives if they dont hold up. Bolt up and forget about 'em factor is huge in my book too. Thanks for all the info.

Re: What exhaust for 311?
 

Croozin2, what exactly do you have under the hatch? What speed are you getting?

Re: What exhaust for 311?
 

Croozin, nice lookin motors - 1st time I have seen the 454mag flat hat filters actually look good.

Looks like you had the same issue with the oil drain lines that are supposed to be able to be pulled out the bilge drain but ends too big to fit. I put mine in just about the same place. Are those quick connects on the end??

Re: What exhaust for 311?
 

Oops. Above I posted that I have the risers welded shut. That's not the case, it was the manifolds, but you probably knew what I meant. The EMI stainless risers just have a solid flange on the bottom, water gets in via a hose.

Re: What exhaust for 311?
 

Sorry so late getting back - been at the river all weekend! I was looking for a previous post I made so I could just copy and paste but here goes,

.030 over, 9.5:1cr, 461ci, stock crank & rods
990 GM heads lightly massaged, Ferrea Valves, 2.30 - 1.88, Crane Gold Rockers
Cam by Cam Motion, Single Pattern Hyd, 236 @ .050, .561 lift
EMI Thunder Exhaust w/stainless 3" extended risers
Crane Hi-6 Marine Ignition w/stock TB-IV dist
Stainless x-overs and t-stat housings
Merc/GM Dual Plane Aluminum Intake
modified Q-Jets (Yeah, I know) w/1" open spacer

Didn't dyno my particular motors but this package has netted anywhere from 498 to 512hp on previous builds. Diamond Engines in Hammond Louisiana did all of the bottom end work. I used to drag race in super stock with the guy 15-20 years ago and he builds some strong motors. After much work with the carbs (Q-jets are really finicky w/ low vacuum signal) the boat increased from 63mph with the stock 454 mags to 72mph and blowing right through these 23" mirages (5500+ rpm). It really accelerates, though. I'm figuring with some 25" Mirages or 24 Bravos or Q-IVs I should see ~75.

Re: What exhaust for 311?
 

Good eye on the quick connects, CMG! I had been using the old method of vacuuming out through the dipstick tube and you never quite get everything out. I had the hoses made up at a local hydraulic hose shop and added the quick connects on the end. Took a 5 gallon plastic bucket and mounted a Teel 12v impeller pump to the top of it. Put the male quick connect on the inlet hose and drilled the top of the bucket and routed the outlet line straight into the bucket. Makes for a sanitary little package.

Thanks for the compliment on the motors. I always like to be a little different so I thought the silver powder coated manifolds topped off with the original flame arresters and covers looked nice (makes people wonder just how stock/modified it really is, too!). :D