2006 28ZX 350 mag upgrades? (28ZX owners help pls)

[In the red]

I just bought a 2006 28ZX with 350 mag MPI's, k planes, corsa quick and quiet (with mufflers removed) bravo 1.65 drives and stock 25p mirage plus props. The boat has 45 hrs on it and is like new. It will currently run 68-69 mph on GPS at 5000RPM WOT and will plane pretty easily as long as you are easy on the throttles out of the hole.

The slip numbers I calculated are pretty low (5-7%). I love the boat and would like to do a couple upgrades this winter to pick up a few mph on the top end without sacrificing planing ability. I know there are members out there that have been through this and are looking for their advice before I spend my hard earned dollars. Some of the options I thought about in order of cost are:

1) Prop work (or 23p for more RPM's or labbed 27p?)
2) Aluminum Exhaust Manifolds (EMI, Hardin, Stainless etc.)
3) Shorty Lowers and new props
4) Whipples!! (I know this is the ultimate but $14K for the two is too much right now.
5) Any other suggestions????

[FISHIN SUCKS]

Welcome to the board, Red:wavey:! There are some numbers 'gurus' on this board that can help decipher what you have better than what I can (I'm kinda like Forrest Gump, 'I'm not A smart man....:nilly:). But I can share with you that I have the twin 350 MAG set-up but with 1.5 drives and 23P and knockin' down 71.9 as a best last year (long lake required, short lake (3/4mi.) I'm only good for about 68). Like you, I love this boat:yes:. However, while I considered upgrades, I would rather have dependability (tired of wrenchin' on hotrods:wrench:). But good luck in your endeavors:kingme:!

So where is home port? Post some pix! Avatar looks good,

tom

[LKSD]

It's a good priority list.. congrats on the new ride! :) Jamie / Lakeside

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[VetteLT193]

As for props go with labbed 27's. The 23's don't work. I know because I have them. you'll be on the rev limiters at 65 MPH.

Another member with the same boat has labbed 27's and is running 74-75 MPH @ 5000.

I'm running 26" Bravo 1's, it runs 65 @ 4800. I think If I lab them I can see 70 and keep my fast cruise and keep it super easy to drive (zero planing issues, no tabs needed ever, etc). I currently run about 55 MPH @ 3800 RPM. I think 3000 RPM it is still above 40 MPH if I remember correctly. That's usually where I keep it... 40-45 in the low 3000's.

I don't think exhaust is worth it. When the time comes for me, I'm going to stick with GLM aluminum. They are easy to bolt on and lighter than stock... You don't have to mess with fitment issues either.

Check out prochargers too. Cheaper than whipple. Probably the best bang for the buck.

[LKSD]

As for props go with labbed 27's. The 23's don't work. I know because I have them. you'll be on the rev limiters at 65 MPH.
Another member with the same boat has labbed 27's and is running 74-75 MPH @ 5000.
I'm running 26" Bravo 1's, it runs 65 @ 4800. I think If I lab them I can see 70 and keep my fast cruise and keep it super easy to drive (zero planing issues, no tabs needed ever, etc). I currently run about 55 MPH @ 3800 RPM. I think 3000 RPM it is still above 40 MPH if I remember correctly. That's usually where I keep it... 40-45 in the low 3000's.
I don't think exhaust is worth it. When the time comes for me, I'm going to stick with GLM aluminum. They are easy to bolt on and lighter than stock... You don't have to mess with fitment issues either.
Check out prochargers too. Cheaper than whipple. Probably the best bang for the buck.

Procharger used to be a lot a bang for the buck. That said their shipping practices & lack of keeping up to date pushed me to not push thier product for almost a year now.. Also they dont support the new models of engines for the last several years now, meaning that they dont have a direct kit for a lot of what is out there. Granted you can make a lot of them work on newer stuff if you want to, but you better know what you are doing & you will need to spend more on top of the kit price to do it right.. I know because I have done a lot of the procharger stuff & at one time was one of thier biggest cheerleaders for marine applications.. My current recomendation would be to go with a whipple. I have done a good ammount of these as well with excellent results. Just remember Cheaper is not alwasy better.. :) Jamie / Lakeside

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[VetteLT193]

Procharger used to be a lot a bang for the buck. That said their shipping practices & lack of keeping up to date pushed me to not push thier product for almost a year now.. Also they dont support the new models of engines for the last several years now, meaning that they dont have a direct kit for a lot of what is out there. Granted you can make a lot of them work on newer stuff if you want to, but you better know what you are doing & you will need to spend more on top of the kit price to do it right.. I know because I have done a lot of the procharger stuff & at one time was one of thier biggest cheerleaders for marine applications.. My current recomendation would be to go with a whipple. I have done a good ammount of these as well with excellent results. Just remember Cheaper is not alwasy better.. :) Jamie / Lakeside
.

That stinks that Procharger isn't keeping up. I'm not a big fan of the low RPM boost that whipple makes for longevity sake.

[BUIZILLA]

wacky paddles all the way... :yes:

[The Hedgehog]

wacky paddles all the way... :yes:

Oh hell yes. The only way to go.:pimp:

[In the red]

Thanks for all the replies, guys. This boat replaced a Red Stingray 230SX with a 496 HO. (Hence "In the red") It was more of a hot rod but I got tired of getting beat up in the rough stuff. The Donzi seems like a Cadillac and the fit and finish is amazing. Would like to know if anyone has tried the shorty lowers on this hull and what kind of performance gains they got. I would guess I would have to go to a 4 Blade with those. Here a a few more pics, the boat was with the original owner in Nashville. My home port is Chapin, SC on Lake Murray.
Jim :shades:

http://i30.tinypic.com/o0tbpi.jpg
http://i27.tinypic.com/oku9ud.jpg
http://i38.tinypic.com/1zn7qed.jpg
http://i28.tinypic.com/213kdnd.jpg
http://i27.tinypic.com/4jnvhi.jpg
http://i27.tinypic.com/21lluad.jpg

[In the red]

Another member with the same boat has labbed 27's and is running 74-75 MPH @ 5000.
I'm running 26" Bravo 1's, it runs 65 @ 4800. I think If I lab them I can see 70 and keep my fast cruise and keep it super easy to drive (zero planing issues, no tabs needed ever, etc). I currently run about 55 MPH @ 3800 RPM. I think 3000 RPM it is still above 40 MPH if I remember correctly. That's usually where I keep it... 40-45 in the low 3000's.

I Might try a set of labbed 27's. I'll call Brett at B-Blades and see what he thinks. I am currently running 40 at 3200, 45 at 3500, and 53 at 4000, 60 at 4500, and 68-69 at 5000.

[Trueser]

Very nice looking Boat!

Plan on AOTH next year......

[BUIZILLA]

I think I saw that boat out on Percy Priest lake before... :yes:

[Trueser]

The cabin looks different. Can i get a close up on the head cover?

Thanks..

[VetteLT193]

I Might try a set of labbed 27's. I'll call Brett at B-Blades and see what he thinks. I am currently running 40 at 3200, 45 at 3500, and 53 at 4000, 60 at 4500, and 68-69 at 5000.

There is a member here, Mr. Fixxall, that has a prop guy with good prices. I'm going to use him soon to do my Bravo 1's. I'm waiting to get new props from Donzi before sending in the Bravos though.

Considering you are at 5000, and the top end is at 5200 for the 6.2's you could just lab the 25's you already have and have them add a little bit of pitch. Labbing will put you up 200-300 rpm, adding a bit of pitch should drop you down 100-200 so you would be at 5100 or so RPM. That would pick up some good speed I think.


A couple guys have this hull with single engine and have done shorties with good results. I'd think with twins the results would be better, but that is just an educated guess.

[The Hedgehog]

That is a beautiful boat In The Red!

Shorty drives work well on some of the ZX's. The twins ZX's are set up a little higher so I dunno. Conventional wisdom says it is a good possibility. I would love to know.

Enjoy the ZX and consider AOTH.

[In the red]

Considering you are at 5000, and the top end is at 5200 for the 6.2's you could just lab the 25's you already have and have them add a little bit of pitch. Labbing will put you up 200-300 rpm, adding a bit of pitch should drop you down 100-200 so you would be at 5100 or so RPM. That would pick up some good speed I think.

That sounds logical. Merc says 4800-5200 on the 350 Mag MPI's. Dustin at whipple told me the stock rev limiters are set at 5450. If that is the case I've got room for some more rpm's Does anyone have any experience with this to know where the stock rev limiters are set on a 2006 350mag??

[In the red]

Thanks! I'll take a measurement on the drive height and shoot a couple pictures of the interior later in the week. The guy lived on the west side of Nashville and we did the water test on KY lake but he told me he had a closer lake also, so he may have been on Percy Priest with it. Tell me about AOTH.

[VetteLT193]

Considering you are at 5000, and the top end is at 5200 for the 6.2's you could just lab the 25's you already have and have them add a little bit of pitch. Labbing will put you up 200-300 rpm, adding a bit of pitch should drop you down 100-200 so you would be at 5100 or so RPM. That would pick up some good speed I think.

That sounds logical. Merc says 4800-5200 on the 350 Mag MPI's. Dustin at whipple told me the stock rev limiters are set at 5450. If that is the case I've got room for some more rpm's Does anyone have any experience with this to know where the stock rev limiters are set on a 2006 350mag??

crap, for some reason I read 350's bust still thought you had 6.2's... sorry, I think I got mixed up because your boat seems to have every other option available.

I am fairly certain Merc says 5000 is the recommended top end for the 350's (4800-5000 suggested top end). 5200 is the 6.2 number. basically, 6.2 vs 350 bumps the range up by 200.

with that said, I'd try to keep it at 5000 or less. same deal applies, just have to tell the prop guy what's what when you send it in so they can add enough cup/pitch to compensate for the lab job. or, slightly de-pitch 27's and lab them.... ooooooorrrrr... run 27's without pitch changed, labbed at 4800-ish based on rough math.

[The Hedgehog]

Thanks! I'll take a measurement on the drive height and shoot a couple pictures of the interior later in the week. The guy lived on the west side of Nashville and we did the water test on KY lake but he told me he had a closer lake also, so he may have been on Percy Priest with it. Tell me about AOTH.

AOTH is the Awakening of The Horses. It is a great event the the Midwest Donzi club has at Lake Cumberland. A bunch of this group attends. It is a GREAT time.

[osur866]

Considering you are at 5000, and the top end is at 5200 for the 6.2's you could just lab the 25's you already have and have them add a little bit of pitch. Labbing will put you up 200-300 rpm, adding a bit of pitch should drop you down 100-200 so you would be at 5100 or so RPM. That would pick up some good speed I think.

That sounds logical. Merc says 4800-5200 on the 350 Mag MPI's. Dustin at whipple told me the stock rev limiters are set at 5450. If that is the case I've got room for some more rpm's Does anyone have any experience with this to know where the stock rev limiters are set on a 2006 350mag??
Can't speak for the 350 mags, but I have a 2006 6.2 and what Dustin has told you seems correct, I have seen 5350 on my 6.2 and watched the tach start to bounce, so I'm sure I was on the limiter take in to account the tach was prolly off by that other 100 then it's probably 5450 as Dustin has told you. As far as the merc operationg range look at the flame arrestor it will say right on there I'm certain both the 350 mag and 6.2 are the same 4800-5200. Steve

[VetteLT193]

Can't speak for the 350 mags, but I have a 2006 6.2 and what Dustin has told you seems correct, I have seen 5350 on my 6.2 and watched the tach start to bounce, so I'm sure I was on the limiter take in to account the tach was prolly off by that other 100 then it's probably 5450 as Dustin has told you. As far as the merc operationg range look at the flame arrestor it will say right on there I'm certain both the 350 mag and 6.2 are the same 4800-5200. Steve

The new ones are the same, 350 Mag Vs 377 Mag. Older ones weren't, 350 mag mpi vs. 6.2 mag mpi

http://www.sea-pro.com/mercurymarine/mercruiser/sterndrives/GasFuelInjected/350-MAG-MPI.htm

http://www.sea-pro.com/mercurymarine/mercruiser/sterndrives/GasFuelInjected/MX-6point2-MPI.htm

I have no clue when it changed though.........

[osur866]

Vette, thats true but the year in question I'm still pretty sure they are the same, it will tell him on the flame arrestor to be sure ;) steve

[In the red]

Can't speak for the 350 mags, but I have a 2006 6.2 and what Dustin has told you seems correct, I have seen 5350 on my 6.2 and watched the tach start to bounce, so I'm sure I was on the limiter take in to account the tach was prolly off by that other 100 then it's probably 5450 as Dustin has told you. As far as the merc operationg range look at the flame arrestor it will say right on there I'm certain both the 350 mag and 6.2 are the same 4800-5200. Steve

Ding Ding you win Steve. Flame arrestor and owners manual confirm 4800-5200 specified WOT range.(The 6.2 is in my manual also and it is the same) I would guess Dustin is correct since they reprogram the ECM's all the time for the Whipple kits. So, I've got a little room to play with on the props.

[VetteLT193]

Keep in mind Vette's numbers are with a different ratio then others on the board. Have you checked the ratio on your drives yet?

Yes... every 6.2 boat seems to have 1.65 ratio. Every 350 Mag boat I have seen so far has 1.5 ratio.

[The Hedgehog]

Yes... every 6.2 boat seems to have 1.65 ratio. Every 350 Mag boat I have seen so far has 1.5 ratio.

I have a 6.2 with a 1.5 in the X-18.

[VetteLT193]

I have a 6.2 with a 1.5 in the X-18.

On re-powers you can do whatever the heck you want, I should have clarified that I'm talking about factory boats, 28ZX specifically.

Look at the links I posted above and you can see the standard/optinoal/high altitude drive ratios that Merc specifies.

For some reason I can't figure out, the 350 Mag is different than the 6.2

6.2 : Gear Ratio - Bravo One (primary/optional/high altitude): 1.65/1.36/1.5
350: Gear Ratio - Bravo One (primary/optional/high altitude): 1.5/1.36/1.65

[LKSD]

That stinks that Procharger isn't keeping up. I'm not a big fan of the low RPM boost that whipple makes for longevity sake.

The whipples wont really be that bad on the drives if you have self control on the throttles and you dont plane off or drive like an animal.. (Although if you are one for hard whole shots then the centrifugal SC units are a little easier on the drives in that scenario, but thats about all.). It's the harsh hole shots & rapid load/unload/load that can really hurt the drives. It's like hitting them with a sledge hammer. Gradual applied torque or initial torque from idle up applied smoothly is not as bad as the whacking the throttles or freewheelin the drives without control when you launch the boat.. ;) Jamie / Lakeside

[In the red]

I think on the more recent boats Donzi has started using the 1.65 drives on the 350 mag. Mine are 1.65's (printed on the sides of the drives) and it came from the factory this way with the 25p mirage plus props. The older 28ZX's I have seen with the 1.5 drives shipped with the 23p mirage plus. All of the more recent mercury specifications (2005 forward) on the 350 mag and 6.2 states 4800-5200 regardless of drive ratio. This is what my Mercruiser Operation manual states which was printed in Feb. 2005.

[VetteLT193]

I think on the more recent boats Donzi has started using the 1.65 drives on the 350 mag. Mine are 1.65's (printed on the sides of the drives) and it came from the factory this way with the 25p mirage plus props. The older 28ZX's I have seen with the 1.5 drives shipped with the 23p mirage plus. All of the more recent mercury specifications (2005 forward) on the 350 mag and 6.2 states 4800-5200 regardless of drive ratio. This is what my Mercruiser Operation manual states which was printed in Feb. 2005.

Cool. yours is the first I have heard of. They just sold another 2008 that had 1.5's on it, so I'm not sure what method they are using to figure out the drives or what it does to performance. I can't say what it does exactly. Mathematically the net result seems to be nearly identical.

[In the red]

Thanks Vette. Yeah, I did the math also when I bought the boat because I new that some had the 1.5 drives. I think I am going to have these 25p props worked first, as you suggested, and see how that works. As you go up in pitch they get smaller, so since I am close now on the rpms, working these may be the best idea. Once I get it dialed in we will see how the 1.65's and 350's work on this boat. Thanks again for you input.
Jim

[FISHIN SUCKS]

Beautiful boat Jim, love the pix!!! While the AOTH event is not until May (weekend before memorial day weekend), you should definitely consider making the trek up. 2009 was the year of the ZX, not sure what 2010's featured Donzi will be yet, but plenty of ZX's will be there!

tom

[In the red]

Trueser, Here are the interior pics you requested.

http://i37.tinypic.com/24xkz9t.jpg
http://i38.tinypic.com/imjgp0.jpg
http://i35.tinypic.com/avlb1i.jpg

[VetteLT193]

Looks nice. I think that is how they look with the Pump out head option. The ones I saw with the pump out head looked like this, the others had porta potti's. I'm not sure on the years though, could have just been a year thing and a coincidence on the options.