Crownline 225 CCR 454 MAG is slow!!!
09-16-2019, 09:48 PM
#31
I don’t get on here much anymore since I retired, but I saw this thread and thought I would share some hard earned experience. As many of you know I’ve spent a lot of time messing with Crownlines. I’ve built engines, setup and driven probably 25-30 of them in the past 25 years, many with 600+ HP. So, here’s what I know. The 225 CCR will run 60-62 with a 454 Mag. and a 1.5:1 Bravo 1 drive and 21 Mirage+. That is by far the fastest prop. Most came with 2.00:1 B3 drives. I built a 600hp 540 for a red 225CCR (just like in the video posted). It would run 70 on a good day. I did a 225 BR with a built 454 with a Whipple that made 750 HP. With a Stern Jack and hydraulic steering it saw a best of 81 on GPS. As far as I know that’s the fastest a Crownline has been, except maybe behind a truck!
09-16-2019, 09:55 PM
#32
I am thinking your tachometer is reading 500 rpm high. That MPI motor has a 5150 rpm rev limiter....meaning you never hit that claimed 5700 rpm with that 18p prop. So that 5000 rpm with the 25p prop is likely only 4500 rpm. So, being over-propped with a smaller diameter Laser (not good on bigger/heavy hulls) you are probably getting slip. So far what you HAVEN'T done yet is put something close to original stated prop on the boat. Both you have tried are on the extreme ends of what the boat needs (too small vs. too big) and boats are really sensitive to that. sometimes going to a smaller prop gains speed if you are over-propped. Too small and you loose speed because you simply are limited to 5150 rpm.
09-17-2019, 05:41 AM
#33
Registered
First things you need to do is get an accurate tach and GPS.
09-17-2019, 07:10 AM
#34
Registered
Im not doubting you here. However someone toldme yesterday the mag efi/mp not mpi didn't have a rev limiter but the original owner told me he's hit the rev limiter before so I obliged to believe your are correct and my tack might be off . If that's the case my cruise speed could be much higher because I'm not turning 3200 rpm like I think I am and instead would be turning 2700 rpm even when the tack is saying 3200. I'll have to find a way to test it.
09-22-2019, 09:08 AM
#35
Ok seems the new 15.25x21 stopped the ventilation boat picked up good and cruises around 3000 rpms well. However 45 minutes into cruising i lost rpm and it died and just clicks wont turn over guess I'll start a new post. Im not sure if im looking at a hydrolocked situation or gimbal bearing.
08-26-2020, 07:33 AM
#37
Well I've had a runn of bad luck with her but the original 454 mag lost oil pressure and cracked the block and crank. I found a couple of 502 mags that I pieced together and had the computer returned. That engine had a noise that sounded like a lifter so I pulled the engine out and broke it down to find nothing wrong with it. I sent it all to the machine shop bought new .030 pistons and have the engine altogether now and ready to go in the boat any day. My sons car needed a clutch and my other sons engine needed the engine pulled. I just got those cars out of the way and now ready to put the new engine in.
09-14-2020, 03:50 PM
#39
cruising at 2600
Finally got the 502 or should I say 508 mag mpi built and installed. I ran it up and down the river for 4 hrs stopping and checking levels. Everything went beautifully for the day. This boat used only 10 gallons of gas in more than 50 miles of travel up and down the river. Either my boat is better on fuel than I thought or my fuel guage is off. Considering it said I had 1/4 tank when the day eas over I will assume it's fairly accurate. Just need to put some more hours on her to break her in. MAYBE Smitty tuned that computer to be efficient
Now I have my sights set on getting the best performance bottom end and top end and I want the most efficient prop for it. I THINK I had the rev limiter kick up to 5350 5400. I read a performance review that says with the 300 hp 7.4 and a 21 mirage prop this boat runs 59 mph. Right now I have a PowerTech OF 15.25x21p prop and well its to new to pound on it just yet but at 2600 rpm she's cruises around 27 mph. I kicked it up to 3500 once but didn't hold it or check gps however I noticed the powerband of this boat starts to wake up at 3500. She seems to take 3200 rpm to get up on plane so it feels sluggis on bottom end. Any recommendations on a prop?
