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View Full Version : New 18 w/ 6.2L



Donziweasel
10-28-2006, 02:42 PM
Thinking about a new 18C and was wondering if anyone had any opinions about the 377 CID 6.2L. According to Mercruiser, it is 30 pounds lighter w/ a Bravo than a 350 Mag MPI. Also has 20 more hp. Pros? Cons? Thanks.

BUIZILLA
10-28-2006, 03:33 PM
IMO, the absolute best 18 power package going...

JH

Last Tango
10-28-2006, 04:54 PM
Had one just like that for the past 6 years. AWESOME combination. FAST and very frugal with the gas. Runs on whatever gasolie you have. Upping the octane rating is not required. Easily smokes the other combinations of stock 350's.
Would do it again.
Look under some of my old posts for discussion on this combo.

rustnrot
10-28-2006, 06:13 PM
Has the new architecture 6.0L "Cadillac Escalade" engine made it to I/O use yet? We got two for v drive use, they are rated 375hp, only come with FWC as they have aluminum heads. PleasureCraft said they would probably be rated 400 hp for '07. A little lighter than the 5.7L.

The 6.2L -- is that a derivative of the Classic 5.7L?

Donziweasel
10-28-2006, 06:23 PM
Must be a good combo because you never see used 18C's on the market with this setup. Seems no one wants to sell one because almost all the used ones have the 350 setup.

Lenny
10-28-2006, 08:24 PM
If I am not mistaken, the 6.2 (Horizon or Scorpion) was only in a "few" boats. 3 or so I thought. One of the reasons you do not see any for sale I believe,... or,... I am completely of base.

Lots of Strokers running around ;) but factory 6.2, I know of only a few.

Donziweasel
10-28-2006, 08:39 PM
I checked with Donzi last week. It is an option (although expensive one) on a new 18C. They also said it was the biggest engine they would put in one. I begged to see if I could get something in the 400hp range (a built 350 CID) and they said they would have no part of it. The price is probably the reason you don't see many. 350 much cheaper.

Speed-Racer
10-28-2006, 08:48 PM
The 6.2 is a great running package.The 6.2 377 Scorpion is a whole nother animal....

Donziweasel
10-28-2006, 08:52 PM
They said the MX 6.L w/ Bravo 1 rated at 320hp was the biggest they would put in a new 18C. Guess you would just have to build an engine. Wonder if they would sell one rigged without an engine or drive?

Magicallbill
10-29-2006, 01:48 AM
If I am not mistaken, the 6.2 (Horizon or Scorpion) was only in a "few" boats. 3 or so I thought. One of the reasons you do not see any for sale I believe,... or,... I am completely of base.
Lots of Strokers running around ;) but factory 6.2, I know of only a few.

Len:
Mine is one of the 377 Scorps..
I've said this before, so I'll say it briefly this time.
I have 350 PSHP with mine.
It cost me $48000.00(I'm still paying..)
It runs flawlessly..
73-74MPH or so...
I'll bet mine's faster than the 6.2 320HP offered nowadays since the Scorp has been discontinued, and mine wasn't much faster than Jason's 350 Mag. on his 18.
I LOVE my 377, wouldn't trade it, but I wouldn't get a new 6.2 that isn't a Scorpion when I could get a 350 Mag.

Rootsy
10-29-2006, 08:11 AM
Gent on DougL's lake has an 18 with a 6.2MX.... nice boat.. runs well... easily 70 - 72 right out of the box.... but she stilll ain't no match for ole yeller ;)

Lenny,

the 6.2 MX and the 6.2 "Scorpion" are two entirely different antimals...

RickSE
10-30-2006, 09:31 AM
rustnrot, no 6.0L's in the stern drive stuff. What sucks though is that they are available in the inboard ski boat world. Merc. just hasn't committed to using them yet.

Donziweasel, Donzi will not sell an unrigged hull, we've already tried that route. Best thing to do is buy one with an easy to sell motor and the drive you want, and then sell the motor.

olredalert
10-30-2006, 09:57 AM
------The way to buy an unrigged hull is to talk a certain Canadian into getting you one,,,,,Possibly a donation to his favorite charity,,,,,LOL.........Bill S

Last Tango
10-30-2006, 11:28 AM
Gang,
Please do not cunfuse the different configurations of the 6.2. Just like the 454 came in many different versions and horsepower ratings, so did the MX6.2MPI and 377 Scorpion.
BOTH engines displace 377 cubic inches. The MX6.2MPI was/and still is built as a 320HP run-on-any-octane-fuel-just-fine motor. Powerful, reliable, and built shortly after the beginning as ECM555 compatible, it was/and still is designed as the engine to replace the 454 Series engines in Mercury's lineup.
The Scorpion 377 was built up by Mercury Racing from the same block as the MX6.2MPI but with a number of hotrodder-style improvements that included a different crankshaft, different pistions, different ECM, different intake and exhaust manifolds, different fuel injection system. This motor REQUIRES PREMUIM ONLY gas. Rated at 350 PSHP this engine was variously noted in boat builders literature as having 340 HP (so-called Black Scorpion), 350HP, and 377HP. The drive-shaft ski-tow boats used the Black Scorpion. If you measure the HP at the flywheel it may also have 377HP there. But manufacturers catalogs and websites print what they want you to see and believe. Examples are Fountain Powerboats get away with charging you for a 29ft boat when it is actually only a 27 foot boot with a 2 foot long beak on the bow.

Mr X has become somewhat of an authority on the Scorpion motors lately. He has a pair of them in his 28ZX Scorpion, and a couple more on the gargae floor. I'm certain he can straighten you out if you have any questions.

As to how many Classic 18's were built with the Scorpion 377 motor option (which is the expensive one, not to be confused with the MX6.1MPI which is worth every penny as an option mated up to the new Bravo One outdrives with 1.5:1 reduction ratio and Mirage 23 Plus prop)... the answer is 6 from the factory. Ever. And no more, since production of the Scorpion motors ended last year.

Magicallbill
10-30-2006, 12:01 PM
Hey Tango;
Since they've become extinct,(I've long wanted to get opinions on this..)Does that make my Scorpion 18 more valuable?
I talked to Josh at Donzi, who I kinda know, and he told me there were 4 made,to the best of his knowledge.
When there were,say, 500 classic Dodge Challenger T/A's made, they became collecter's items..
I would think that 6 Donzi Scorpions would constitute some kind of value.

Donziweasel
10-30-2006, 05:47 PM
I never really considered the Scorpion when looking for an 18C. The only drawbck to one it seems is the fact that you have to run high octane gas. Magicallbill, I would think that if you have the Scorpion, it would definetly be more valuable than a regular 6.2L (MX), especially if only 6 were made. What year is yours out of curiosity?

Like I said, from the factory, the biggest they will put in an 18C is the MX 320horse.

Here is a good question- Since 1965, what is the biggest engine ever put into a stern drive 18C? Not including V-Drives and Jets, which I am sure came with bigger engines. We know they made 6 377 Scorpions, anything bigger?

Got a price from one of the board members who's family is a Donzi dealer on a new one with a 6.2 w/Bravo. The price was less than I thought. Then, of course, the member started asking if I was interested in a 22C:wink: (the answer is "hell yes", but not in the budget and my wife said "hell no"). In any event, I am probably going with the new 18C if I can get it at the price we discussed.

The overall opinion seems to be that the MX 6.2 320 horse w/ bravo is a great match for the 18 C. Due to the fact that I am dealing with an 18%-21% loss of horsepower at my altitude, I would think that the bigger engine (with more air through it) would be a better performer than the 350 Mag. Both are fuel injected, which will definetly help.

So, this spring, look for me at the Awakening in Kentucky and I would love to get to Powell with some other Donzi folks. Still want to know the biggest factory engine every installed in an 18C though, so give me your best guess.

Magicallbill
10-30-2006, 10:03 PM
Donziweasel;
My Scorpion 18 is an '02.

You will really dig the 18 however you power it.

I personally don't know of a 18 with a higher rating than the 350PSHP Scorp, but maybe someone here does.

One thing..If you get the 6.2 over the 350 MAG,it'll be a little heavier aft than the MAG.Dual batteries(an inclusion with my Scorpion)the weight of the Bravo over the Alpha..I'm not sure about the diff. in the weight of the two engines.

In my Scorp, that translated into more Chinewalk at 70-plus..My son Jason's 18 with the 350 was rock-solid and it ran in the high 60's. Only difference I saw was the weight factor.
We had a unique opportunity to side-by-side compare the two rigs..Exact same hull with different power.

I personally liked his 350/Alpha,as it seemed perfect for the hull

BUIZILLA
10-31-2006, 06:34 AM
The absolute best looking 18 I have ever seen, IMO, was the ice blue version that Robert Nelem sold... without a doubt, it was the classiest combo going. Robt has a knack for spec'ing Donzi's with interesting color combo's that really *pop* in your eyes, and bring out the lines of the hull.

JH :cool:

Last Tango
10-31-2006, 02:24 PM
The new generation Bravo 1 drives are actually lighter than the previous gen of Alpha's and certainly far stronger. Alpha's are rated up to 300HP which means you are pushing the limit with the 350 MAG. However, MX6.2MPI's come standard with the new Bravo 1 drive and that drive is rated up to 400HP.
Dual batteries are NOT standard with the MX6.2MPI. They are an option. Scorp's often had dual batteries. Not always. My MX6.2MPI never needed a second battery. I owned it 6 years and the battery never failed. I sold it with the original battery still in place and the current owner has no issues with it. Battery weight is not an issue.

I ordered trim tabs (worthless on an 18C - plenty of threads discuss this) and a depth meter (worth 10 times it weight in gold!).
I got the stock thru-hull exhausts with NO Quick-N-Quiet pipes. The stock Corsa baffled tips are plenty growly and meet the noise requirement on the sanctioned lakes.

After the first year, I voluntarily replaced the stock exhaust manifolds and risers with the EMI Thunder fully polished versions. Hooked right up to my exhaust tips without a hitch. Added lots of shine to the engine compartment, removed over 100 pounds of ugly black cast iron from the weight in the stern, improved the ride, and top speed by 3 MPH. The boat was delivered with a Mirage 25 Plus prop, but I soon after switched to a Mirage 23 Plus and never looked back. Boat easily topped into the low 70's.

Chine walk onset happens at 70 MPH (GPS) on the C18 hull. So a stock 350 MAG would never have that problem since it can't push the boat that fast. Chine walk can easily be controlled with the fine tilt trim control for the drive. A quick touch down and the boat settles a little bit more hull back into the water and keeps it moving without a drop in speed. Chine walk actually slows the boat, and is a hairy thing to try to drive through. Boat is faster when allowed to settle a little more hull. Chine walk means you have the boat trimmed too high for that speed. The boat can be trimmed high for running in the 60's but actually needs a touch of down for breaking through the chine walk barrier.

Donziweasel
10-31-2006, 05:21 PM
Tango- Just out of curiosity, why did the trim tabs do nothing for you? I installed them on my 16 and it took care of the propoising between 35 and 45 mph and the chine walk about 53 mph. I know the 18 is a different beast, but do not think they helped at all? How about with the chine walk?

Ok, here is where I need some help. The MX 6.2 w/ bravo is $2,300.00 more than the 350 mag w/ alpha. Here are the weights from Mercruiser-

6.2 w/ bravo- 993 pounds
350 mag w/alpha- 946 pounds
350 mag w/ Bravo 987 pounds

Difference of 47 pounds bewteen 6.2 w/bravo and 350 mag w/alpha. Is it worth the extra $2,300.00? Realistically, an 18 might run over 70 mph at sea level, but up here that same boat is probably more around 62-63 mph. I have a ski boat (Moomba) so I do not need low end, but want my high end speed. The money is not that big a deal when you are spending over $30000.00 on a new boat. Either way, might talk to JW eventually about some bolt on ponies, but want a good solid package to start with. 6.2 or 5.7? If 5.7, Alpha or Bravo?

olredalert
10-31-2006, 06:07 PM
-------Start with a package you can supercharge down the road. That way your elevation problem will be counteracted by the boost or pressure.........Bill S

BUIZILLA
10-31-2006, 06:17 PM
6.2 / Bravo

was I clear on that?:)

Donziweasel
10-31-2006, 06:24 PM
Loud And Clear:)

gold-n-rod
10-31-2006, 06:52 PM
Robt has a knack for spec'ing Donzi's with interesting color combo's that really *pop* in your eyes, and bring out the lines of the hull.
JH :cool:

Bob "had" a knack. Unfortunately, he's no longer a Donzi dealer. :(

Pismo
10-31-2006, 07:03 PM
A 377 Scorp 350pshp with a Bravo sounds great, with an Alpha sounds perfect. Used to run 400hp thru a pre-alpha with no problems and currently 450+hp thru an Alpha on a 22 with no problems for 20 years so I am sure the drive could handle it on a small 18. An Alpha SS may be even better. Would be quick. Great thread.

Donziweasel
10-31-2006, 08:11 PM
Wish they still made the Scorpion, but I seems to me for my altitude, 47 pounds is not much of a scarifce for the extra hp. How do the 5.7 and 6.2 behave throughout the torque curve?

Last Tango
10-31-2006, 08:30 PM
An 18 is an entirely different boat than a 16. Period. That 2 feet makes a huge difference. My 16C worked better with it's trim tabs to control porpoising. You will also get that same good feeling by adding a Stingray to the drive. One or the other on a 16. Not both.
18 is a completely different handling and performing boat than a 16. Neither handles like a 22C. These are not apples.
Trim tabs of no value on the 18, but are useful on the 16 and the 22. Also good on my current '06 22ZX and they were helpful on my Z3250 Daytona with twin 454 Mag MPI's and Bravo One outdrives.
Almost NEVER used them for anything on my 18. Others have experienced the same. Unless you are reguarly trying to hold the boat on plane at low speeds (skiers?), or are carrying an extremely uneven load port to starboard. I have had trim tabs on many different Donzi's and they were extremely useful. The 18 just doesn't need them for anything. And for that, you should be thankful $$$$.

As for the Alpha/Bravo drive - Alpha is rated by Mercury Marine for up to 300HP. What you do with it on your own, and for how long, is up to you. Mercury Marine does not offer the MX6.2MPI with an Alpha drive as standard. Check their website. But you can get what you want. Better to pay up front for what works than to pay later for what doesn't work.

Cuda
10-31-2006, 08:56 PM
Personally, I'd go with the 350 mag and an Alpha drive. My reasoning being they have made the 350 for many, many years. I think the Alpha drive is plenty strong for a small block on that size boat, and your pulling less gear through the water compared to a Bravo. I'd also say that weight difference is due to the drive, not the engine.

Also, I don't know this to be true, but I've read that a 6.2 isnt'a good candidate for supercharging due to the location of the rings on the pistons.

As far as tabs, I've never had an 18, but I never use them on my Minx, and Deb's 22 doesn't have them, though I think her's did have them at some point. The tab controls are still there, and you can see on the inside of the transom where they used to be mounted. The only time I've had a porposing problem on the 22, is if I had a lot of weight in the rear seat, and only at about 30 to 35 mph. As a side note, I have 280 trim tabs on my 302 Formula, and I never use them. When I bought the 302, the previous owner told me I had to drop the tabs and the drives to get on a plane (surface drives), but once I hit the wrong tab, and the boat skeered the chit out of me. I since found it will get up just fine without using the tabs.

Donziweasel
10-31-2006, 09:07 PM
Thanks for the advice Cuda. If I am going to spend the money on a new boat, I just want to make sure it is set up right.

Tango, I know the ratings of the drives and what drive is offered with each engine. You are right, the 6.2 is only offered with the Bravo, but you can get the 5.7 with either and Apha or Bravo. Weight is 7 pounds lighter if you get the 5.7 w/ the bravo vs. the 6.2 w/bravo. Thanks for the advice on the tabs. How sensitive is the 18 to negative or positive trim on the drive?

Magicallbill
10-31-2006, 10:37 PM
Tango;
Interesting stuff that you say on the trim app. to control chinewalk.
As I stated in my earlier post, my Scorpion starts walking at 70+ I am really trimmed out at that point,and when it gets really nutso, I chop the throttle back.I'll try a little neg.trim next year when I get it back out.
I only use my tabs to compensate for passengers,and/or a headwind on the port or starboard quarter.(A Deep-V leans into the wind.) They are totally unnecessary in all other aspects of handling&performance.
Jason said the same thing Cuda did;There is something to be said for the long-term dependability of a 350..They've been producing them for so long, they've got it down. His 350MAG/Alpha was turn-key from the git until he sold it to Brad Hicks this winter.
My Scorp, on the other hand,had several issues with the Bravo,and a leak thru the exhaust jackets,or something like that.
In all fairness, I will say that the 377 Scorp. ran perfectly,and still does.

smokediver
11-01-2006, 07:37 AM
just to pipe in a little .... my 383 broke an alpha gen2 on the 3rd time out ... no holeshots, going airborne , cruising at 3000 rpm and bam ! i would get the bravo if available .. it is cheaper in the long run , especially if you re-power down the road . engines are cheaper than transom assemblies and outdrives ...

Donziweasel
11-01-2006, 05:57 PM
Talked to JW today and he said the 6.2L is a great candidate for supercharging. His only concerns were room under the hatch and the difference in setup from his shopto my altitude (ie: Pulley diameter vs. fuel pressure at high altitude). He did come up with another suggestion which I ran by my dealer. Can't say what until I have an answer, probably next week. I have had some suggestions about the 350 vs. 6.2, most seem to think by going 350, I will save weight and therefore the boat will be as fast as an 6.2. We are only talking 47 pounds here and I am just not sure that will make the top end any faster. If I decide to supercharge, then will go with the 6.2 for sure, because the benefits of the bigger engine outweigh the weight savings I believe.

BUIZILLA
11-01-2006, 06:38 PM
Maybe there are some Lake Tahoe connections that have superchargers to pick their brains, it's about the same altitude... I would SERIOUSLY research this, before committing to that thought circle.

JH

blackhawk
11-01-2006, 06:44 PM
I ran with a guy that had a 6.2 Bravo package and it was a cool little hot rod. He said he could run 70-72mph. From what I saw I'd say he would probably be close in some light chop. But, we were running in some pretty sloppy water and he couldn't keep the boat in the water. Every time he tried to really trim it out he would launch the bow. Maybe some K-planes would help control this?

Donziweasel
11-01-2006, 07:30 PM
I am really sycked about the new boat, just want it to run right. Blakchawk, I have been told that trim tabs are worthless on an 18, but needed on the 16 and 22. Any thoughts?

Just Say N20
11-01-2006, 07:47 PM
I am really sycked about the new boat, just want it to run right. Blakchawk, I have been told that trim tabs are worthless on an 18, but needed on the 16 and 22. Any thoughts?

Oh good. Another trim tab debate :wink:

I don't know of any offshore racer who runs a V-bottom boat that doesn't have trim tabs. They have done a lot of research to figure out how to make their boats run as fast (and safe) as possible. My experience is that tabs can give you additional control over the ride attitude of the boat as conditions dictate.

blackhawk
11-01-2006, 07:58 PM
I am really sycked about the new boat, just want it to run right. Blakchawk, I have been told that trim tabs are worthless on an 18, but needed on the 16 and 22. Any thoughts?

Honestly I can only comment on what I saw. He may have been REALLY trying to hang it out and kept pushing it. But he did it several times over a 8-9 mile WFO run. My U19 didn't need tabs but the hull has hook to keep the bow from launching, the trede-off being less top-speed.

Donziweasel
11-01-2006, 08:38 PM
Just wondering if I should get them. Bought my 16C without and it would porpoise around 30-40 mph and chine walk around 52 mph. Put on some Bennetts and the Tabs eliminated both, but been told it is not a problem on the 18. I know this topic has been beat to death, but I have only owned a Donzi since July and been on the boards about as long.

By the way, I am a fan of the Unlimiteds- nice one on ebay-

http://cgi.ebay.com/ebaymotors/1996-FOUR-WINNS-UNLIMITED-171-LOW-HOURS-WOW_W0QQitemZ170043531071QQihZ007QQcategoryZ63686Q QrdZ1QQcmdZViewItem

Donziweasel
11-01-2006, 09:21 PM
At my atitude a 375 hp engine at sea level will be only 300 hp up here. The extra hp shouldn't be an issue unless I go over lets say 400 hp, but even that would only be around 320. I figure a 6.2 L rated @ 320 hp will only be around 265hp up here. Supercharging with 3-5 psi will only push it to 330-340 max.

blackhawk
11-02-2006, 12:16 PM
Just wondering if I should get them. Bought my 16C without and it would porpoise around 30-40 mph and chine walk around 52 mph. Put on some Bennetts and the Tabs eliminated both, but been told it is not a problem on the 18. I know this topic has been beat to death, but I have only owned a Donzi since July and been on the boards about as long.
By the way, I am a fan of the Unlimiteds- nice one on ebay-
http://cgi.ebay.com/ebaymotors/1996-FOUR-WINNS-UNLIMITED-171-LOW-HOURS-WOW_W0QQitemZ170043531071QQihZ007QQcategoryZ63686Q QrdZ1QQcmdZViewItem

That is a clean Unlimited! Someday I want another 19 for a smaller second boat. :D

blackhawk
11-02-2006, 12:21 PM
As far as an 18 "launching in anything more than a light chop", sure, they will. Especially if propped poorly, and with crappy steering.. I would have to say there are several board members here that have seen my 18 run hard in a bit more than light chop, and it is perfectly controllable.. Sometimes to the embarrasment of much larger boats.. But, it's dialed in fairly well.....
And that brings up another issue: If your going to be hopping up this boat, dont forget steering... And I would just go ahead and order the BXR, cause a standard bravo aint gonna handle the HP you plan to boost the engine too, so why buy two drives??

Sorry I wasn't trying to step on anyone's toes. I'm sure an 18 can run hard in slop I was just commenting on the one I saw launching out of the water. It appeared to me that tabs would have helped him run the boat more level and keep him from getting out of shape, but that was just an observation.