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View Full Version : Prop to try? Same post, both sites.



Just Say N20
07-22-2015, 09:59 AM
Long-winded Bill is back. :cool!:

I'll just toss this out there to see if someone might have something hiding on a shelf that might be of use. Although I can't imagine why someone would have a 28" 4-Blade Left Hand prop just sitting around.

As some know, Ed Donnelly and I traded boats last summer. The Criterion, of which I am now the proud owner, has had at least 3 "stages." It came from the factory with a 370 hp 454. The boat is a left hand drive (the proper side from which to drive), and has a TRS drive. In the original configuration, I assume the boat ran a 21" 3-blade cleaver. I have 2 of these props.

Then, Ed, in true Ed fashion, went full in and had a 1,000+ hp twin turbo engine built for the boat. Perhaps he was just curious to see what 100+ mph felt like in a 22 versus how it felt in a 16. I don't know. But for this engine, he ran a 30" 4-blade Bravo I prop that has been reworked to a 31" pitch.

After experiencing the 100+ mph rush in the 22, Ed decided that it was a "bit much" and put the original 454 back in, with the addition of a Weiand supercharger. Horsepower is unknown. Unfortunately, shortly after this engine was installed, Ed's health prevented him from using the boat more than a few times. In this configuration, the boat ran either a 24" 4-blade Bravo I, or a 24" 4-Blade Intimidator Q-IV.

Hang with me here.

The blower HAD a 3.48" top pulley, which produced just under 3 lbs of boost. I have run both the 24" Intimidator Q-IV, and the 31" Bravo I with this configuration. The 24" Intimidator Q-IV seems to be a very good match for this boat, kind of. With it, the boat runs 78 GPS, but at 5,800 rpms. I didn't build the engine, so I'm not exactly sure what is in it, but I'm not comfortable running a 454 at that kind of rpms. By the way, it sounds AWESOME!

The 31" Bravo I prop ran 73 mph at 4,500 rpms. Surprisingly the boat has no problem planing with it. As I expected, it is too much prop for the engine to really run.

Trueser also let me try one of his labbed 26" 3-Blades that was maybe a 27 after the work. The boat hated it! Best I could get was 5,000 rpms and barely 70 mph.

Now, the plot thickens. My son-in-law and daughter gave me a smaller (3.04" I believe) pulley for Christmas. I did some engine "tuning" prior to swapping pulleys. This was relatively easy, as the boat has an AFR gauge, and dual exhaust temp gauges. I got the carb jetting to where the AFR numbers are good.

Results running the smaller pulley, and the 31" Bravo I are as follows. The engine now has 5 lbs of boost, and ran at 4,800 rpms. However, the top speed remained at 73. It seems that on this boat, with the TRS drive, that prop slips a lot. It starts to lose grip fairly early when trimming, and continues to get worse.

Based on how the Intimidator Q-IV runs, I would love to try a 28" one of those. I have NOT run the boat with the 24" Intimidator and the higher boost. Based on picking up 300 rpms with the 31" prop, I would probably pick up 500 rpm with the 24. And I'm already at 5,800, so as Monty Python would say, "5 is right out." You're welcome Ghost.

The catch is that this is a Left Hand set up, so I would need a left hand prop. I have the insert for Mercruiser props.

I am going to put the 24" 4-Blade Bravo I, and the two 21" 3-Blades cleavers for sale. I will keep the other 2 until I find an appropriate replacement.

If anyone has a prop that might be interesting to try, and are willing to let me try it, let me know.

Conquistador_del_mar
07-23-2015, 02:34 PM
Bill,
I would highly recommend trying this prop with your setup description. The Rev4 hooks up and responds well on every deep V boat I have tried it on including TRS drives. Another Bill

http://www.ebay.com/itm/MERCURY-MARINE-REVOLUTION-4-PROPELLER-LH-25P-LAB-BOAT-PROP-/111412109768?hash=item19f0ade1c8&vxp=mtr

Just Say N20
07-23-2015, 02:53 PM
Thanks Bill.

Thanks for taking the time to post the link. I'm not sure moving from a 24 to a 25 would be enough increase in pitch. Generously, 150 rpm loss for every inch of increased pitch is all I have ever seen. I would like to keep the rpms around 5,200 max.

I believe I would need at least a 28', maybe 29" pitch. A guess would be the engine is putting out maybe 550 hp.

Conquistador_del_mar
07-24-2015, 12:25 AM
The Rev4 hooks up like nothing else I have seen. I'm running 74MPH in my 28' Warlock at somewhere around 5100RPM with a 25P Rev4. Might be worth trying.

Greg Guimond
07-24-2015, 06:25 AM
The Mercury Rev4 is the same geometry as the Tempest Plus and should work very well on the Critter. The prop is designed for deeper drive depths and has a lot of blade area. They tend to run a little stiff compared to a Bravo prop which tends to run a touch under pitch. Another prop worth a look would be a Turbo Fusion 4 if the drive is higher but it won't be as good "all around" as the Merc in your app I suspect.

Carl C
07-25-2015, 04:51 PM
All of your speed results seem low for a blown 454. Your prop choices and results are all over the place. Bravo 1s are overrated in pitch by 1 or 1 1/2. I'm running a 30p Bravo 1. I could not pull a 30p in any other prop that I am aware of. I would shoot for at least 5,400 RPM. Just some thoughts. I don't know what to tell you on prop choices based on your previous results. . . . . .

gcarter
07-25-2015, 07:20 PM
FWIW, Catch22 (Jim Collins) ran a supercharged 454 w/a 30 or 31
Hydro Q4 and ran around 92. It seemed to be a worry free/ drama
free setup.
Bravo w/-2" lower.
This is the way I remember it anyway.

Just Say N20
07-26-2015, 12:49 AM
Interesting. Bravo shorty is probably a big help. I don't know if TRS drives are usually considered "fast."

Carl, the TRS drive could also be why the speeds are lower than what you would expect.

gcarter
07-26-2015, 07:49 AM
Interesting. Bravo shorty is probably a big help. I don't know if TRS drives are usually considered "fast."

Carl, the TRS drive could also be why the speeds are lower than what you would expect.

Bill, the Merc "number" racing lowers are based on TRS uppers.
You'd have to decide which is the cheapest way to go, i.e., the cost of a Bravo and a shorty,
VS. the cost of a Merc racing lower.....
You can frequently find them on eBay and other places.

Just Say N20
07-26-2015, 08:48 AM
Being solidly "middle age" at 59, and not making an income that is dependent on how fast the Critter goes, I am just looking for a prop that is a good match with the engine as it currently performs. :)

I'm sure a numbered drive would be awesome, however squeezing every last mph out of this setup is not my priority at the moment.

Greg Guimond
07-26-2015, 01:03 PM
I have a Turbo Fusion 4 27" that I would ship you to try out if you ship me (to CT) your Bravo 24" prop to do the same on my boat. I also have the same Turbo prop in a 26".

MDonziM
07-26-2015, 08:49 PM
Bill,

My 2c on several things mentioned here: As for props, I would have thought that a TRS which were generally rigged deep as to X-dim that a 3 blade mirage plus would be best... If the 4 blades are better, the Bravo 1's and Hydramotives are similar but I believe the q4's might not give as much bow trim/carry. I don't know anything about Rev4's or Fusion's. If you have a B&M 174/Weiand 177 blower running 4.5-5lbs of boost on an old Merc 420 spec built 454 you should have 550hp. When you find the right prop I would not run that motor over 5200 rpm as the supercharger is just producing heat past that rpm and a very inefficient charge.

- M

Just Say N20
07-26-2015, 10:22 PM
I have a Turbo Fusion 4 27" that I would ship you to try out if you ship me (to CT) your Bravo 24" prop to do the same on my boat. I also have the same Turbo prop in a 26".

Happy to send the Bravo I 24" your way. You do remember they are all LH props. . .

If you still want it, pm me your address. Likewise, if the 27 is a LH prop let me know.

Just Say N20
07-26-2015, 10:34 PM
Bill,

My 2c on several things mentioned here: As for props, I would have thought that a TRS which were generally rigged deep as to X-dim that a 3 blade mirage plus would be best... If the 4 blades are better, the Bravo 1's and Hydramotives are similar but I believe the q4's might not give as much bow trim/carry. I don't know anything about Rev4's or Fusion's. If you have a B&M 174/Weiand 177 blower running 4.5-5lbs of boost on an old Merc 420 spec built 454 you should have 550hp. When you find the right prop I would not run that motor over 5200 rpm as the supercharger is just producing heat past that rpm and a very inefficient charge.

- M

Marshall, your statements are spot on. Trueser thought the 3-blade Mirage would be good, but the boat didn't like it at all. Too bad, as it was a labbed prop. The drive is a little deep. I wish I knew why the Q-IV 24" seemed like a magic prop. I thought 78 for that set up was really good. Ran well and was very predictable. But spinning the engine into furnace territory.

I was told the engine was the 370 hp 454. I'm new to the BBC world, but Ed told me the engine had forged internals.

It is the small Weiand blower. Good low end and mid-range performance, but definitely a heat machine on top end.

Ed Donnelly
07-27-2015, 07:30 AM
I bought the Criterion from John Chisholm and it was a 370 hp.
E erything is forged. Ralph at Rapid my engine builder confirmed everything.
Sorry to hear about the starter motor. Still no steering in the 16...Ed

Just Say N20
07-27-2015, 10:29 AM
Ed, It may, or may not be the starter. It could be a simple bad ground wire.

It was a phenomenal week end with respect to the weather, and with multiple other Donzis available for getting my son a Donzi ride, I couldn't see spending the week end in the bilge trying to track it down.

Thanks for confirming about the internals on the engine.

What is the hold up with the steering? Are parts slow in coming? I hope you get it installed soon!

Greg Guimond
07-27-2015, 11:35 AM
Happy to send the Bravo I 24" your way. You do remember they are all LH props. . .

If you still want it, pm me your address. Likewise, if the 27 is a LH prop let me know.


I did not look closely at the thread as the weather this weekend was great for boating. Do you mean the prop shaft on your TRS drive rotates counter clockwise?

Greg Guimond
07-27-2015, 11:51 AM
All of your speed results seem low for a blown 454. Your prop choices and results are all over the place. Bravo 1s are overrated in pitch by 1 or 1 1/2. I'm running a 30p Bravo 1. I could not pull a 30p in any other prop that I am aware of. I would shoot for at least 5,400 RPM. Just some thoughts. I don't know what to tell you on prop choices based on your previous results. . . . . .


Interesting. Bravo shorty is probably a big help. I don't know if TRS drives are usually considered "fast."

Carl, the TRS drive could also be why the speeds are lower than what you would expect.

The starting point to all of this is the prop shaft centerline depth in relation to the bottom of the boats keel. I'd suspect if Carl leveled his trailer, leveled his Bravo drive and got that accurate depth for his rig you could then do the same for the TRS and start to compare. Bravo's came in two versions, one version had BOTH side water inlets and low inlets in the nose. The other (and more common) drive had just the side water inlets so the drive had to be a bit lower beneath the keel. All this assumes that a Critter has the same bottom as a 22 Classic (I have no idea) and that Carl's 22 and your Critter both make about the same horsepower.

Gear case depth tells a lot at the start. The lower units overall profile is the second piece of the puzzle.

Just Say N20
07-27-2015, 01:17 PM
I did not look closely at the thread as the weather this weekend was great for boating. Do you mean the prop shaft on your TRS drive rotates counter clockwise?

Yes, left hand prop = counter clockwise rotation.

The Critter has the same bottom as a 22. This boat has transom mounted water pick ups. I don't think there are water pickups anywhere on the drive.

I'm guessing your props are standard RH (clockwise) rotation.

Just Say N20
07-29-2015, 08:43 AM
Greg, The 2nd 24" prop is NOT a Bravo 1, it is a Mach Stern Driver LH, 14.5 x 24. My mistake.

I've got a Rev 4 25" coming from BBlades to try.

Greg Guimond
07-29-2015, 09:12 AM
Greg, The 2nd 24" prop is NOT a Bravo 1, it is a Mach Stern Driver LH, 14.5 x 24. My mistake.

I've got a Rev 4 25" coming from BBlades to try.

If the drive is deep the Rev4 will solve all of your problems :yes:

Pat McPherson
07-29-2015, 10:10 AM
I've measured the prop shaft on my 22 to be approx 7" below the bottom. It's very deep for sure. Running real light, my stock 502 with Gil exhaust will turn nearly 5000rpm with the boat topping out at 73mph GPS with a 1.5 Bravo and 25P Rev 4.

My guess is that you've got approx plus 100HP over my 502 but will lose an extra 20 thru the trans and TRS.

Let's make a prediction on your results with a 25p Rev 4. - 78 mph @ 5600rpm:yes:

By comparison, I recall a fellow running a 600HP 502 Bravo drive in a 24 Pantera hitting 80 at 5800 with the 25pRev4.

Just Say N20
07-29-2015, 10:22 AM
Sounds like a pretty good prediction Patrick.

I want to try and limit the RPMs to around 5,400 max. My understanding is that the smaller blower I have becomes a furnace much over 5,200. It is great for mid-range performance enhancement, but not great if WOT is all you do.

Greg, I don't know how deep the drive is. I will check that out this week end.

Redink
07-29-2015, 10:55 AM
Yep, Agree with Patrick. He turned me on to the REV 4. I am thrilled with the performance and handling at all speeds. Top speed so far is 70.5 GPS. That's only off by .5 MPH of the three bladed 25P Turbo. :cool!:

Greg Guimond
07-29-2015, 11:27 AM
I've measured the prop shaft on my 22 to be approx 7" below the bottom. It's very deep for sure. Running real light, my stock 502 with Gil exhaust will turn nearly 5000rpm with the boat topping out at 73mph GPS with a 1.5 Bravo and 25P Rev 4.

Patrick, a prop shaft centerline that is 7" below the 22 Classic's keel is perfect for the attributes of the Rev4 prop. They are designed to run a little on the deep side and are happiest at 4" below and greater.
I'm going to bet that the prop shaft on Bill's new Critter is 6 1/4" below the keel. Hole shot will be very good and overall handling will be exceptional.

I don't know chit about car motors so I won't even guess on the top speeds and rpms with the Rev4 prop swinging left. Should be interesting.

Conquistador_del_mar
07-29-2015, 01:01 PM
Greg, The 2nd 24" prop is NOT a Bravo 1, it is a Mach Stern Driver LH, 14.5 x 24. My mistake.

I've got a Rev 4 25" coming from BBlades to try.

I think you will be pleased with all the characteristics of the Rev4 and I look forward to hearing your synopsis.

Greg Guimond
08-01-2015, 06:42 AM
Long-winded Bill is back. The Criterion, of which I am now the proud owner, came from the factory with a 370 hp 454. The blower HAD a 3.48" top pulley, which produced just under 3 lbs of boost. I have run both the 24" Intimidator Q-IV, and the 31" Bravo I with this configuration. The 24" Intimidator Q-IV runs 78 GPS, but at 5,800 rpms. The 31" Bravo I prop ran 73 mph at 4,500 rpms. Now, the plot thickens. My daughter gave me a smaller (3.04" I believe) pulley. I did some engine "tuning" prior to swapping pulleys. The engine now has 5 lbs of boost. Results running the 31" Bravo I are 4,800 rpms, top speed remained at 73. I have NOT run the boat with the 24" Intimidator and the higher boost.


Thanks Bill. I'm not sure moving from a 24 to a 25 would be enough increase in pitch. I would like to keep the rpms around 5,200 max. I believe I would need at least a 28'. A guess would be my engine is putting out maybe 550 hp.


Marshall, your statements are spot on. The TRS drive is a little deep. I wish I knew why the Q-IV 24" seemed like a magic prop. I thought 78 for that set up was really good.


I've measured the prop shaft on my 22 to be approx 7" below the bottom. It's very deep for sure. My stock 502 with Gil exhaust will turn nearly 5000rpm at 73mph GPS with a 1.5 Bravo and 25P Rev 4. My guess is that you've got approx plus 100HP over my 502 but will lose 20 thru the trans and TRS. Let's make a prediction on your results with a 25p Rev 4 ....... 78 mph @ 5600rpm.


Sounds like a pretty good prediction Patrick. I want to limit the RPMs to around 5,400 max. Greg, I don't know how deep the drive is. I will check that out this week end.


Hopefully Bill you have received the new BBlades 25" Merc Rev4 prop and can try it this weekend to see if Patrick's prediction of 78mph rings true. You should also bring the 24" Hydromotive Intimidator Q-IV and run that just for a comparison. I have one in the garage that I'm going to dust off against my Rev4. Btw - there is a left rotation 28" Q-IV up on ebay.

mattyboy
08-01-2015, 11:14 AM
Bill

some thing to keep in mind when talking a critter with a trs sometimes you can't compare straight headsup to a 22C performance wise the critter tends to be a bit heavier as does the trs with the tranny from a bravo setup the critter will ride better though.

Greg Guimond
08-10-2015, 08:43 PM
Hopefully Bill you have received the new BBlades 25" Merc Rev4 prop and can try it this weekend to see if Patrick's prediction of 78mph rings true. You should also bring the 24" Hydromotive Intimidator Q-IV and run that just for a comparison. I have one in the garage that I'm going to dust off against my Rev4. Btw - there is a left rotation 28" Q-IV up on ebay.

I tried my Q-IV against my Rev4. I find the Rev4 to be a lot more predictable across all ranges. It also tends to lift the entire boat, not just the bow. The Q-IV was a little faster but not by much. I like Rev4's so much I picked up another one off CL for $210 delivered yesterday.

Just Say N20
08-10-2015, 11:45 PM
Testing results. The boat liked the Rev 4.

RPM, Nuvī GPS, air/fuel ratio, boost gauge

Rev 25
1,000 - 6.5, 13.6, 10 hg
2,500 - 31, 14.2. 8 hg
3,000 - 38, 14.5, 6 hg
3,500 - 45, 14.2, 4 hg
4,000 - 52, 13.4, 2 hg
4,500 - 59, 12.1, 0
5,000 - 67, 11.9, 1.5 lbs
5,500 - 74, 11.9, 5 lbs
5,700 - 75.5, 11.9, 5 lbs

Greg Guimond
08-11-2015, 03:46 PM
Rev4's solve a lot of problems. I'm sure your TRS drive is deeper than Patrick's Bravo is at 7" below the keel of his 22 Classic. Time to sell all your other props and find a used Rev4 as a spare.

Greg Guimond
08-26-2015, 08:51 AM
Long-winded Bill is back. :cool!: If anyone has a prop that might be interesting to try, and are willing to let me try it, let me know.

So did the Merc Rev4 prop end up curing all your Critter's speed and handling problems?

Just Say N20
08-26-2015, 04:52 PM
The bottom line is yes. The boat liked the prop. Felt like a really solid bite. That prop appears to have a lot of rake.

HOWEVER, a stock 25" pitch is not enough. It still allowed the engine to spin to 5,600 - 5,700.

I have since traded a Hydromotive Intimidator Q-IV 24" for the same prop that started life as a 28" pitch, and is stamped that it was reworked to a 26.5". That concerned me, as my experience has been that most people will only try and change a S/S prop about an inch of pitch.

Anyway, the boat liked the Q-IV about 90% as well as the Rev 4. But, it was about 2 mph faster through out the range above 2,500 rpms. I had to trim like a crazy person to get the rpms to 5,450. Normal trim at WOT was about 5,200. This is right where I would like to be. Slip at WOT was just over 15%.

Air/Fuel ratios, and exhaust temps were right where they should be. Actually the exhaust temp at WOT was 1,100, and Keith suggested I could go to 1,250. That means I could most likely add some timing. However, not making my living driving this, I would rather run a little less timing, and not have things go BANG!

Greg Guimond
08-26-2015, 05:19 PM
Maybe trade the 25" Rev4 for a 27" and call it a day. Keep the Hydromotive Intimidator Q-IV 26.5" you have as a backup prop.