Tell me about my Prop... Does it seem right for me?

[trayson]

So, I just went outside and to the best of what I can see, I have a 13" prop that has a 11.5 pitch. I have a 92 Sunsport with the pro boss, so I've got the higher horsepower (265 according to Nadaguides.com). And I have a PCM 40i 1:1 transmission.

So... what do those prop specs tell me?

I'm wondering if it's optimal for my usage. I wakeboard and wakesurf the vast majority of the time. Every now and then I'll try to ski, but I'm not very good and I just kinda cut around and play. No serious course stuff or any of that.

What's got me wondering is that it seems like I don't have quite enough power... Today while surfing, we couldn't get quite up to the 11.5 to 12mph that we've been surfing at. This was with about 1300 pounds of ballast. A 235 pound guy in the rear corner and another 150 pound guy in the rear middle seat, and 130 pound driver. However, when we moved the 150 pound guy to the observer seat, we were able to surf at our desired speeds... Of course, weight distribution has a lot to do with how the boat was planing (or NOT planing). But the experience got me to thinking about what prop would be best suited for my needs. (not that I really want to throw down the $$$ on a new prop!!!!!!!!!!!!!!)

I do have one ding on one of the tips. I'm sure that getting that fixed would help overall performance. You might be able to see it in this pic:
The tip that's facing down to the bottom isn't a perfect curve at the very bottom of it:
https://lh5.googleusercontent.com/-2pLGhdOv4t4/UhpFp-knRaI/AAAAAAAAO1Y/m1MeIM3ecWQ/s800/20130825_103250.jpg

https://lh6.googleusercontent.com/-lbpRX262SiI/UhpFTsbBpEI/AAAAAAAAO0o/BoVRDR27Qbo/s800/20130825_103240.jpg

[villain]

http://www.nettleprops.com/store/p/280-Acme-913-Propeller-3-Blade-13-X-10-5-LH-1-Bore-080-Cup.aspx


My prop and we were running with 2500#s ballast, 3 adults, 3 kids, cooler full of beer. Still able to run 20 mph on plane. Still able to run 35mph to ski when completely empty also.

[trayson]

http://www.nettleprops.com/store/p/280-Acme-913-Propeller-3-Blade-13-X-10-5-LH-1-Bore-080-Cup.aspx


My prop and we were running with 2500#s ballast, 3 adults, 3 kids, cooler full of beer. Still able to run 20 mph on plane. Still able to run 35mph to ski when completely empty also.

Well, next weekend you'll have to give me your opinion of my setup in person. I'm just about maxing out my engine with 1300 pounds of ballast surfing at 11.7 mph and 3 people in the boat. I do porpoise a LOT when surfing, but I'm hesitant to change anything because I'm pretty happy with the surf wave so far.

BTW, I did a "top speed run" today and found I was able to go 43 MPH at 5600 RPM's with 3 people in the boat and no ballast. (finally had smooth enough water to open her up!)

[villain]

5600 rpm!?!?!?!?!? Do you have the gt40? If not your twisting that thing way to high. I hate spinning mine over 4400rpm.

[trayson]

5600 rpm!?!?!?!?!? Do you have the gt40? If not your twisting that thing way to high. I hate spinning mine over 4400rpm.

It's the PCM 351 Pro Boss. It was really the only time I've ever taken it up that fast, and I figured that I'd see what it could do. Yeah, typically is rarely sees speeds more than the low 30mph range.

[Blackntan90]

Yeah 5800 seems high to me as well. My manual says 'Do not exceed 4400 RPM for more than 1 minute'. So every now and then I like to see if she can get there, but only for a couple of seconds. I am running the 240 HP 351, not the 'Pro Boss' -Maybe she can take a few more RPM? ideally you should only get to your max RPM with the correct prop. Mine is the stock 13X13 NiBrAl, with the 1.23:1 trans. so it may be different RPM range than yours.

[kvand347]

5600 rpm's seems waaaaaaay too high! Manual says max intermittent rpm's is 4600. If you are getting 5600 then you are probably not propped correctly. We have to keep in mind you run the 1:1 trans instead of the original 1.23:1, but I'm not sure it makes an 1,000 rpm difference!

[92SupraComp]

whoa! what happened to your 1.23:1?? Also, 5600 rpm to high. but wont hurt your motor. The whole reason PCM uses the Ford is low end torque, and the bottom end can handle quite a bit. Friday I did a WOT Throttle run for about 3 miles. Boy was it roaring :P Until my friend passed me doing 63 mph! lol

Oh, and your motor is 285hp. Not 265. You still have the 4010 Holley right?

[trayson]

whoa! what happened to your 1.23:1?? Also, 5600 rpm to high. but wont hurt your motor. The whole reason PCM uses the Ford is low end torque, and the bottom end can handle quite a bit. Friday I did a WOT Throttle run for about 3 miles. Boy was it roaring :P Until my friend passed me doing 63 mph! lol

Oh, and your motor is 285hp. Not 265. You still have the 4010 Holley right?

Well, all I know is that the people on the forums tell me that my boat supposedly came with the 1.23:1 according to my engine tag, and I know for a fact that I have the PCM 40i 1:1 in there now, as I just had a rebuild on it.

I just bought the boat in April, and I think that IF the tranny was swapped, it happened before the previous owner had it. Because he gave me the old prop from the boat that he dinged up and it's the same direction as the current prop. So if the tranny was swapped, the prop was swapped as well. I guess that's okay with me because I don't know if I would want a prop that rotates CW because I like my CCW rotating prop and the surf wave it produces because I surf regular side.

https://lh5.googleusercontent.com/-L49EiCWMd8s/UVzUKrmy_TI/AAAAAAAANxw/1Wl7QBLnrHI/s800/%255BUNSET%255D.jpg
https://lh3.googleusercontent.com/-EyCzHyX2G_g/Uc5k7oH2NGI/AAAAAAAAOOo/_SaczbpSHoQ/s800/20130628_201537.jpg

[trayson]

whoa! what happened to your 1.23:1?? Also, 5600 rpm to high. but wont hurt your motor. The whole reason PCM uses the Ford is low end torque, and the bottom end can handle quite a bit. Friday I did a WOT Throttle run for about 3 miles. Boy was it roaring :P Until my friend passed me doing 63 mph! lol

Oh, and your motor is 285hp. Not 265. You still have the 4010 Holley right?

I have whatever carb this is:
https://lh4.googleusercontent.com/-6YKc7ETT2Cs/Uc5j4sLL8XI/AAAAAAAAONQ/78OBzC4s9Og/s800/20130628_202015.jpg
https://lh6.googleusercontent.com/-HoTAQayj6G4/Uc5kvQHyf_I/AAAAAAAAOOQ/2VkiAVEaots/s800/20130628_201448.jpg
https://lh5.googleusercontent.com/-wx_1m_F36sU/UVzUNt6O4SI/AAAAAAAANxw/ev2zy-5GX7I/s800/%255BUNSET%255D.jpg

[92SupraComp]

NOOOOOOO!!!! Wow, your poor boat has been miss matched up a bit. No longer has the large "muffler" behind the motor, no longer have the 4010 Holley that it should, has a retrofitted 1:1 tranny. Boy, someone sure has done a number on that thing...

How it should look:

13053

[trayson]

NOOOOOOO!!!! Wow, your poor boat has been miss matched up a bit. No longer has the large "muffler" behind the motor, no longer have the 4010 Holley that it should, has a retrofitted 1:1 tranny. Boy, someone sure has done a number on that thing...

How it should look:

13053

So, it seems that aside from the obvious transmission change that the carb would be the biggest difference. Does the carb that I have on there decrease performance???

It sure makes me wonder what happened in my boat's history. But then again, a lot can happen over 20+ years...

[92SupraComp]

Proper 4010 Holley it should have...

13054

[trayson]

Oh, and your motor is 285hp. Not 265. You still have the 4010 Holley right?

So, given the various things that don't match up, is it safe to say that I really do have the 285 HP that supposedly my engine tag alludes to???

[trayson]

Proper 4010 Holley it should have...

13054

Interesting. Well, I've read some threads just now and most of them say that the 4010 isn't anything to write home about. that many boat manufacturers abandoned them in favor of the 4160 that supposedly performs better in marine applications. If that's the case, it might be a good thing that I don't have the 4010.

[92SupraComp]

well, thats the thing. CC dealers had their mechanics remove the 4010 carbs before even selling the boats unless requested not too. Dont know why. PCM as far as many people can tell only did this for 1992 Pro Boss HO motors. Reason being, the 4010 is a far higher performance carb than the 4160. They are an extremely simple/basic design which allows then to be very reliable, sort of. Holley stopped making the 4010 due consistency, the 4010 lacked this greatly. One day perfect idle, and great performance, next day, crap idle and not performing as it should. The 4160 is able to stay consistent for a long time. However, the 4010 will beat ANY carb of the same size. EX. 600 CFM vs 600 CFM 4010, 4010 will win. They have great hole shot capabilities from the factory. Thanks to marine environment being pretty consistent mine always performs very well. So, really you are lacking the better hole shot the 4010 provides, but other than that, I dont believe you are loosing power due to it. Just loosing the more rare and interesting look it gives...

Mine works very well all the time, and it has cool sound compared to my CC and other boats running the 4160, the 4010, you can really hear the secondaries open up under the hood and out the exhaust, the sound is very different from under the hood...

[92SupraComp]

Oh and to answer your question yes, you have the 285 HP motor. PCM had 2 HO Pro Boss Motors, the Carb'd 285 HP version, and the 310 HP TBI motor. Me and you have the 285 hp version. Although, my poor motor is missing the GT40P heads :sad:

[trayson]

Oh and to answer your question yes, you have the 285 HP motor. PCM had 2 HO Pro Boss Motors, the Carb'd 285 HP version, and the 310 HP TBI motor. Me and you have the 285 hp version. Although, my poor motor is missing the GT40P heads :sad:

Actually that is the next thing I was wondering about... Does my motor have the GT40 heads or not? I've heard they are a cool upgrade, but got confused as to what exactly the "Pro Boss" has that gives it the 285hp over the lower base model engine with the 240. I've never heard what exactly "pro boss" included...

[92SupraComp]

The thing Pro Boss means for 1992 is:
GT40(P) (I believe they are gt40p heads, might be mistaken)
Holley 600 CFM 4010 Carb
3.5" Exhaust Risers
Pro Tec Ignition

The Protec ignition was an option on its own, you could get the powerplus package with or with out the protec...

The level were in 1992:
Power Plus Package - 240 HP Level 351w with 1.23:1 Tranny (the 1.23:1 has an angled out put, there for level the motor and making the intake even to all cylinders rasing it from 230 HP to 240 hp)

Power Plus Package w/Protec - same as above, only with Pro Tec Electronic Ignition, dont know if received a higher HP rating.

HO - GT40(P) heads

HO Pro Boss - GT40(p) heads, holley 4010, 3.5" Exhaust risers, pro tec ignition

These I believe were the option for the Ford 351W from PCM in 1992.

[92SupraComp]

So, buying gt40p heads would be a waste of money, however, I would check the head casting marks to make sure they are gt40 heads. You can buy heads just as good as new gt40 heads for the same price and sometimes less. The arent super special, just a bit better than the crap stock heads, anything aftermarket will blow them away, literally lol

[trayson]

The thing Pro Boss means for 1992 is:
GT40(P) (I believe they are gt40p heads, might be mistaken)
Holley 600 CFM 4010 Carb
3.5" Exhaust Risers
Pro Tec Ignition

The Protec ignition was an option on its own, you could get the powerplus package with or with out the protec...

The level were in 1992:
Power Plus Package - 240 HP Level 351w with 1.23:1 Tranny (the 1.23:1 has an angled out put, there for level the motor and making the intake even to all cylinders rasing it from 230 HP to 240 hp)

Power Plus Package w/Protec - same as above, only with Pro Tec Electronic Ignition, dont know if received a higher HP rating.

HO - GT40(P) heads

HO Pro Boss - GT40(p) heads, holley 4010, 3.5" Exhaust risers, pro tec ignition

These I believe were the option for the Ford 351W from PCM in 1992.

So, according to your list I have the GT40 heads, the 3.5" exhaust risers, the protec ignition, and would have had the 4010 but that was swapped out for a different carb (the 4160 I'm guessing?).

Does that sound right??

[92SupraComp]

Yes, that is right. Me and you Should have identical setups. Mine is factory except the heads, and my "muffler" is hollow. You obviously have the pro tec, the 3.5" risers, dont have the 4010, but you do seem to have the correct 4160 replacement, the 1:1 direct drive instead of the 1.23:1, as for the heads, check the casting marks. Google like, gt40p head markings, or gt40 head identification. I dont not know if these should be the gt40 heads or the gt40P heads...

[trayson]

thanks for all your help. I'm learning a lot. I'll look soon to see if I have the three vertical bars that distinguish the GT40 heads, just to be sure I know that I for sure have what I think I have!!

Here is the pic I found online about making sure you have the GT40 head markings:

http://www.skidim.com/images/351HOhead.jpg

That said, I think that it might be worthwhile to think about a prop upgrade sometime in my future (when i can afford it)

[DAFF]

5600 / 1.23= 4552 rpm. Your prop would be perfect if the trans was geared correctly. Given the power under the hood I might try to find the correct trans rather than messing with the prop. Get one which needs a rebuild for cheap and then re-sell yours and break even.

[92SupraComp]

DAFF, his prop is NOT correct for the 1.23:1 Tranny. If his prop is spinning at 5600 rpm to achieve 43 mph, then if you reduce the speed to 4552 rpm, thats even slower. The propeller is set up to run 5600 rpm on a 285 hp motor. If take the 5600 * 1.23 = 6888. So his motor would then try to turn over 6k in order to max the load on the prop.

The higher reduced transmission you have, the bigger the prop you need. Thats why master crafts run big props, they have 1.52:1 transmissions. thats also why they have a great advantage. My friends 1985 230HP Master craft, gives my 1992 Supra comp and run for its money, and now that I dont have the gt40 heads, I think he gets out of the hole just a bit quicker...

[phathom]

How much of a noise reduction did the muffler make? Also is it possible the muffler was removed more likely for clearance of the new tranny or more so for performance?
The reason I ask, is because we were contemplating a homebrew FAE setup on this, but wondering if replacing this muffler should be done first or left as is and go straight to the FAE.

Also being one of the guys who pulled and reinstalled the tranny. I am not looking forward to doing a swap back to a 1.23:1, especially if it would cause an inferior regular side surf wake.

[92SupraComp]

Well, Supra wanted a loud exhaust, so the muffler really doesn't quiet it at all like the MC, or CC's of the 80's. But, my Supra, with the hollow muffler, is heard over 2 miles. Extremely loud. The mufflers trayson has, are like $150 each, they are a stainless muffler, easy to find. But, they dont do a whole lot. Our friends put them in on their 89 Sunsport because the small mufflers in the back have most of the baffles broken out, he said the stainless ones barely knocked the sound down at all. Really, if you want your boat quieter, buy a custom muffler like the CC guys, or by a Centek Silencer, your boat will be so quiet. My 89 CC has the Centek Invertaflow Silencer from factory, boy is that thing quiet!

[trayson]

5600 / 1.23= 4552 rpm. Your prop would be perfect if the trans was geared correctly. Given the power under the hood I might try to find the correct trans rather than messing with the prop. Get one which needs a rebuild for cheap and then re-sell yours and break even.

My understanding is that the prop rotates the opposite direction on the 1.23 transmission. My prop is CCW. So having to buy a new transmission AND a new prop is not in the cards.

Plus, as Phathom said, we're not interested in pulling the transmission again.

[trayson]

5600 rpm!?!?!?!?!? Do you have the gt40? If not your twisting that thing way to high. I hate spinning mine over 4400rpm.

Well, that kinda makes sense. If the standard pitch is 13 and I am running 11.5 then yeah I guess it would make it so the engine would rev higher for a given speed. I did an RPM caluclator and it said that for 43 MPH if I had the stock prop that my RPM's would drop from 5641 down to 4990. Still pretty high, but more realistic for probably how the boat was built. The lower prop pitch that I have (11.5) is like having lower gears on a car. Makes a lot more sense now...


Yeah 5800 seems high to me as well. My manual says 'Do not exceed 4400 RPM for more than 1 minute'. So every now and then I like to see if she can get there, but only for a couple of seconds. I am running the 240 HP 351, not the 'Pro Boss' -Maybe she can take a few more RPM? ideally you should only get to your max RPM with the correct prop. Mine is the stock 13X13 NiBrAl, with the 1.23:1 trans. so it may be different RPM range than yours.

Yeah, I was only there for a few seconds. It was kinda fun I have to admit though. Hope the old 351 took the little bit of abuse I threw at her!


5600 rpm's seems waaaaaaay too high! Manual says max intermittent rpm's is 4600. If you are getting 5600 then you are probably not propped correctly. We have to keep in mind you run the 1:1 trans instead of the original 1.23:1, but I'm not sure it makes an 1,000 rpm difference!

"correct" is a matter of how the boat is to be used. Yeah, I'm not propped "correct" to get top speeds. I am proped well for more UMPH for out of the hole and pulling loads (like surfing). I just have to be my own "rev limiter" I guess.

[DAFF]

Sorry about the bad math skills guys. Have been working some weird hours the last few days and sleep is of the essence. Just getting up for another round of watering sod. Worst of all the first time I multiplied and my logic side of my mind was thinking 1.23 turns of the prop to the engine and that why I used division. So the gear reduction is beneficial in the launch, top speed or using ballast ??

Re prop would be the EZ fix.... Forgot about all the trans issues you just went through.

[92SupraComp]

Gear reduction is beneficial all around, It allows the motor to spool up quicker, and also, much less cavitation and stress on the prop.

At 1.23:1 4400/1.23= 3577 rpm at the prop

at 1.52:1 4400/1.52= only 2895 rpm at the prop...