How fast has anyone pushed a Bravo 1 XZ gear case without a nose cone? Was told around 90 MPH depending on the X diminsion, is where it will blow out.

I run mine at 75mph, no blow out, just need to steer ahead of the chine walk. I would think at over 80mph you would need a nose cone

2 500s xz drivs 85mph no swet

we run over 90 with them on a v bottom with a very high x,no problem

Are you running a cat or a V-Bottom? we have seen a 6 to 7 MPH gain over 90 MPH with the Imco lower housing versus the stock Mercruiser lower housing. On a catamaran hull. THEY WORK GREAT!!!!

Goodfella,
I'm about to try this out on my 25' Daytona. Did you see 6-7 with just that change or did you have to bump prop pitch also?

Goodfella, Its on a V. A 2000 35 Twin step Fountain. Im looking at possibly putting Whipples on my 500 HP EFI's, Dustin thinks the boat may run 101 to 103 MPH. Thanks for the input!!

I've run mine to 106mph...25 hours no problems

Hey Beak and Cat,
This is what really happens when you change out the lower housing to an Imco. For one it is hydrodynamicly more effieciant than the XZ or XR lower. Especially if you are running the Low water pick up Mercury Housing. The water comes off the Mercury housing goes into the LWP and hits a BRICK WALL. When you get a chance look into the pickup area of a Mercury housing. Also the Imco housing gives the propeller cleaner more efficiant water so your RPM might go down a bit becaues you are loading the prop better.Which means more MPH!!! We had 2 brand new 32 Skaters one with 500 EFI and one with 575 SCI Mercury Racing engines. They both ran 106 MPH! The customer with the 575SCI was pissed becaues he spent alot of extra jing$$$ to go faster. We called Pete at Skater and he said it was the lower housings.Now what I am gonna tell you is the TRUTH! Dave at Imco can back me up. We put Imco lower houisngs on the 575SCI boat and it ran 126 MPH!!!!!!!!!!!!!!!!!!

Goodfella,
When you added the Imco did you use a unit that changed the prop shaft height? If not, that is a good apples to apples comparision. It would be interesting to see what the HP500efi boat would do with the same change.

Rick