Donzi 38ZX Whipple upgrade and Handling Questions
12-26-2018, 01:21 PM
#1
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Donzi 38ZX Whipple upgrade and Handling Questions
I have a Donzi 38ZX 525 EFI’s with XR Drives and hydraulic steering. I’m researching options to get the speed in the mid 90’s or better. I like the boat and I know it’s not the best platform for higher speed but I’m happy with it and I just want to get what I can out of it. I’m planning on refreshing the motors, increasing the valve spring pressure closed to 180lbs on the seat, looking at adding the 525 EFI stage 2 Whipple SC and upgrading the drives to the IMCO drives. I have heard all the goods about the Whipple upgrade and I’m wondering:
1) Does anyone have any negative story’s about the Whipple 525 EFI package or input for preparation?
2) Does anyone input on handling issues at high speed with the Donzi?
3) Does anyone Have any input to strengthening the XR drives to handle 850 horsepower without having to step up to IMCO drives.
4) Other suggestions and am I missing anything?
1) Does anyone have any negative story’s about the Whipple 525 EFI package or input for preparation?
2) Does anyone input on handling issues at high speed with the Donzi?
3) Does anyone Have any input to strengthening the XR drives to handle 850 horsepower without having to step up to IMCO drives.
4) Other suggestions and am I missing anything?
12-26-2018, 01:40 PM
#2
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I think you should sell your XR drives and bolt on the IMCO SCX drives. Members on this site have had great success with the power you’re seeking, size of your boat and the SCX drives.
12-26-2018, 01:51 PM
#3
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Thank you SecondWind!! I that's what I was thinking. I was just seen if anyone had an option that to keep the XR Drives, so I didn't have to list and sell my drives. I was hoping to upgrade them because I hate trying to sell parts.
12-26-2018, 04:01 PM
#4
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The Whipple kit is great. Will look like a factory engine when they’re done. But it’s not cheap either. The valve train of the 525 is definitely something that should be gone through and replaced. There is extra plumbing/rigging required with the intercooler but that’s not that big of a deal imo. You’ll need a sea or sand strainer for the intercooler. Biggest issue is getting drives to live. I tried and XR and was showing signs of impending failure after only 5-10hrs. So had to drop another 18k on a drive.
12-26-2018, 05:17 PM
#5
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Thanks IGetWet!!, First, off that's a beautiful site!!! I'm thinking the stock valves from the 525 should be okay, with a valve job (seats cut and valves ground), heads milled and new springs adjusted with shims (as need). Does that sound similar to what you had to do for the valvetrain? Did you go to the IMCO drive or did you have someone beef up the XR's?
12-26-2018, 05:52 PM
#6
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Talk to George at All American Drive Service, he might be able to put together a Bravo based package for you like his Phase 4. He will most likely also recommend Drive Guardians due to weight and hp you plan. IMCO SCX with the new dual shaft lower would be the best option but also the most expensive. Good luck with your build! http://www.allamericandriveservice.com/Hi-Performance.html
12-27-2018, 08:09 AM
#7
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I started with a Imco SCX. Didn’t like how the boat felt, sold it, tried a XR for craps and giggles, found gears pitting after about 5hrs. Bit the bullet again and bought a SCX-4. Much happier with how this drive makes the boat feel. Peace of mind is a big plus too but they do take mor HP to turn and push through the water.
12-27-2018, 09:50 AM
#8
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I hate to be negative but you really should look at buying a faster boat. I know you don’t want to hear that but it will be much cheaper in the end. You will get killed on resale if you ever decide to sell down the road. Your at a crossroads that many people face. I almost did the same thing your talking about a few years ago but decided to sell the boat stock. There’s nothing you can do to keep those drives alive with that size boat and hp. The imcos are great drives but not cheap. Half the speed you gain from the whipples your going to give back running those drives. Your boat is very sellable the way it sits, Enjoy the boat for what it is or I would buy another boat built and rigged with upgraded hardware. Good luck.
12-27-2018, 10:30 AM
#9
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Trying to get a Donzi 38ZX to run in the 90s seems like a reasonable goal. From what I've heard they run low 80s w/ 525s. That's hauling the mail for a boat that size w/ all of the amenities. A 90 plus mph ZX would be a fun boat, a sleeper. It's probably going to cost North of 70K for the Whipple and drive conversions without increasing the boat's value, but hell it's only money.
Last edited by SecondWind; 12-27-2018 at 10:31 AM. Reason: bad grammar
