I just switched from an Imco SC to an SCX , top and bottom , I lost about 4 mph ...but the piece of mind is worth it . this is a
27ft V bottom with about 850 HP

Hello all,

About 50 hours ago I installed Whipple Stage 2 Superchargers to my 38 ft Donzi ZRC. The boat weighs about 8700 lbs. I recently blew up the port side drive completely and bent shafts and pitted gear on the other. I've made the decisions to go with the IMCO SCX uppers. I'm now pushing 825 HP each side. My plan today was to keep the existing Bravo XR ITS lowers with new shafts and gears to save a few bucks. Tonite I think I may be making a mistake and should also go with the SCX 1400 lowers. Any guidance is appreciated as I'll be making my final decision in the morning. I like to run it hard and it's super fast. Hopefully you will see the Shelby Blue Donzi ZRC at the Tampa Poker Run with the Whipple logo on the side. Thank you.

DJ

I did the swap from XRs to SCXs about 4-5 yrs ago now. Couldn't be happier. Lost some top end speed-Yes- Lost Boating Time due to fuked up drives- NO

I would allways go with an Driveguardian at this powerrates!
The XR lives then long i think.
They are wirth the money.
Michael

Hallett Fan,

Did you do both the uppers and lowers or just the uppers and redo the existing Merc lowers? That's my dilemma.

Tks,


DJ

Same situation. Just blew my first XR upper on my 38zx w/575sci putting out just around 700hp each. Not sure to just swap it for another XR and chance things, or cut to the chase and go with something beefier.

At Bravo anf much HP it would use driveguardian!
I am sorry that i am in germany,as i have an new from merc XR Sweptback Upper for sale for 3900 $.
Seacore version and with gurantee from merc.
Also a complett drive from it!
If someone have idea to shipp easy,this let me know!
I use now DG by myself. Michael

The Driveguardian is interesting for sure, but for the cost and effort the SCX seems like the more surefire and simple solution to the problem I have. The boat itself has had 3 sets of XR's in its 500 hours that I know of, about to be a 4th. Everyone says its a matter of when, not if the XR gears fail which has me ruling out anything that has them inside it. On top of that I know for a fact my engines make more power than the XR is rated for and are known to survive behind, so using them (or one based on it) seems like asking for trouble.

Truth be told, I'm still not certain if I blew the upper or lower, I find that out tomorrow. In either case, during the 45 minute ride home on one engine literally its very first day out this year, my dock in sight the entire time; I decided that at minimum I would be having both drives fully rebuilt or replaced new no matter what was wrong. I'm kind of kicking myself for not having this done along with the new transoms, engines, and everything else I did last year, but the oil looked clean and I took a chance going for another season. Back then I most likely would have just gone for another set of XR's and a prayer, now I'm almost fully decided against them.

It took me about 5 or so rebuilds before I went SCX's. Couldnt be more happy.
Yes i lost some speed. but going almost 5 years with NO Issues was totally worth the cost. And with all the rebuilds I probably almost paid for them anyway.

Then you can do more of THIS ^^^^^

The Apache is a nice touch!

How much speed did you lose with just the SCX uppers? I have spare XR lowers and planned to run the season with the SCX upper only but my shop is fairly convinced that I'll lose far more than 2mph in the uppers alone which sways that camp back to the rebuilt XR uppers and a prayer. I haven't gotten to really use the boat in 12 months, and am quite anxious. Turns out my uppers are not broken, I either took out the lower shaft, or the lower coupler. Now I question using the lowers but that is a whole other discussion.

The boat is a loaded 03 38zx, completely fresh 575's making 700 per side, almost on the dot. It has a genset, and a bunch of other luxury weight. It broke the lower just cruising and had a full tank when it happened. I don't want frequent downtime and although it seems I am just trying to talk myself out of it; the internet opinion is SCX, however locally anyone I would go to and trust to put it on seems to think that would be not worth the cost and speed loss. If I'm looking at 10mph losses thats a real bummer, but 2 plus I can drive it like I stole it on occasion seems like a good trade off.