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79nautique
Grand Poobah
Joined: January-27-2004
Location: United States
Status: Offline
Points: 7872
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Posted: March-19-2008 at 5:38pm |
rpm's depends on if it's a stock motor or not I ran mine all the way up to 6K but it wasn't stock, mid 4K for a stock motor
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TRBenj
Grand Poobah
Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 21113
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Posted: March-19-2008 at 5:50pm |
79nautique wrote:
rpm's depends on if it's a stock motor or not I ran mine all the way up to 6K but it wasn't stock, mid 4K for a stock motor |
Based on what?
Its my theory that PCM's recommended max RPM is based on the powerband of the engine- not the strengh of its internal components. There is absolutely no difference that I am aware of between the bottom ends of the HO 351w (285+ hp) and the non-HO 351w (240-255 hp), yet the max recommended RPM varies by 400 RPM (4400 vs. 4800).
I can vouch for the fact that turning a non-HO 351w over 4400 RPM improves performance. I turned my 240hp motor over 4600 and gained holeshot AND top end with the Acme 470. Im not afraid of turning 5200+ on the same bottom end now that Im pushing more power.
Kristof, long story short, I would expect your WOT RPM's to be on the order of ~4700-4800. The 351w is plenty strong and will not be damaged by doing so. If youre happy with the all around performance, dont worry about a thing.
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79nautique
Grand Poobah
Joined: January-27-2004
Location: United States
Status: Offline
Points: 7872
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Posted: March-19-2008 at 5:59pm |
TRBenj wrote:
79nautique wrote:
rpm's depends on if it's a stock motor or not I ran mine all the way up to 6K but it wasn't stock, mid 4K for a stock motor |
Based on what?
yet the max recommended RPM varies by 400 RPM (4400 vs. 4800).
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well isn't that mid 4K's and isn't that right out of the manual Timmy?
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TRBenj
Grand Poobah
Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 21113
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Posted: March-19-2008 at 6:04pm |
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79nautique
Grand Poobah
Joined: January-27-2004
Location: United States
Status: Offline
Points: 7872
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Posted: March-19-2008 at 6:16pm |
yes I did, I stated basicly the same thing with out interducing my "theory" about what it should be. And you come back "based on what" bull***************,
based on common knowledge, based on reading the manuals in the past, based on what other stock motors run from the factory that I have riden in Timmy, so I wasn't specific enough for you soory it's because it was a general question with no set exact RPM because there are too many factors effecting what the RPM might be or should be at WOT.
guess next time I'll dig out a print out for you eastcoaster's to see the facts in black and white, but then maybe it wouldn't be the same print out you would come up with.
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BuffaloBFN
Grand Poobah
Joined: June-24-2007
Location: Gainesville,GA
Status: Offline
Points: 6094
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Posted: March-19-2008 at 6:22pm |
Does his fuel system affect the equation?
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1988 BFN-sold"It's a Livin' Thing...What a Terrible Thing to Lose" ELO
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79nautique
Grand Poobah
Joined: January-27-2004
Location: United States
Status: Offline
Points: 7872
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Posted: March-19-2008 at 6:24pm |
BuffaloBFN wrote:
Does his fuel system affect the equation? |
can if it's not tuned right
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BuffaloBFN
Grand Poobah
Joined: June-24-2007
Location: Gainesville,GA
Status: Offline
Points: 6094
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Posted: March-19-2008 at 6:32pm |
Chris, from what I've read here from you and others, a lean condition is bad across the board...but I think he's on propane.
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1988 BFN-sold"It's a Livin' Thing...What a Terrible Thing to Lose" ELO
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TRBenj
Grand Poobah
Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 21113
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Posted: March-19-2008 at 6:39pm |
79nautique wrote:
based on common knowledge, based on reading the manuals in the past, based on what other stock motors run from the factory that I have riden in
guess next time I'll dig out a print out for you |
Im well aware of what the manuals say. I quoted the max recommended RPM's stated by PCM above. I disagree with them. I'll break it down for you, since youre having trouble following me.
As you know, the Acme 470 would not have been the stock prop on an '89. Due to its lower pitch (15") compared to the factory prop (16"), it will turn more RPM's. This helps holeshot, but due to its improved design, also increases the top end speed (I have witnessed this personally). Win-win.
The only drawback (if you could call it that) is that the max RPM's increase about 200 over the stock prop. The question is, will this damage the motor? I say no.
I think we would both agree that the bottom end of a stock 351w is far from weak, and that the 4400 max RPM rating is very conservative. PCM themselves recommends a full 4800 RPM on the same bottom end in the HO version of the 351, which uses the same internals.
Its my opinion that, in this case, exceeding the max RPM recommended by the factory will do no harm. Kristof may burn a little more gas with the extra revs, but thats really the only downside.
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Kristof
Grand Poobah
Joined: October-08-2007
Location: Bree, Belgium
Status: Offline
Points: 3391
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Posted: March-19-2008 at 6:45pm |
I'm enjoying yet another bashing LOL
I just went to the kitchen to get a beer and some chips... go on boys!!
I'm on propane. The installation is well tuned by a specialist and if there is still a loss in HP, it's minor (about 5 HP he says)...
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- Gun control means: using BOTH hands! - Money doesn't make one happy, but when it rains cats and dogs, it's still better to cry in a Porsche than on a bicycle...
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8122pbrainard
Grand Poobah
Joined: September-14-2006
Location: Three Lakes Wi.
Status: Offline
Points: 41040
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Posted: March-19-2008 at 8:56pm |
Kristof wrote:
I'm on propane. The installation is well tuned by a specialist and if there is still a loss in HP, it's minor (about 5 HP he says)...
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kristof, You may want to check on the HP loss. I don't care what your mechanic has said or how well tuned he has got your engine running. The loss in HP is more like 10%. It is a simple fact that there are less BTU's in propane and hence less energy.
The lower pitch that Tim is recommending will be good with less HP.
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Kristof
Grand Poobah
Joined: October-08-2007
Location: Bree, Belgium
Status: Offline
Points: 3391
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Posted: March-19-2008 at 9:09pm |
Ah, OK Pete. Thanks. So in this case I would lose some 26 HP?
I'll let you all know how she runs. Can't wait to hear her roar on the water again! Come on spring!!!
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- Gun control means: using BOTH hands! - Money doesn't make one happy, but when it rains cats and dogs, it's still better to cry in a Porsche than on a bicycle...
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Riley
Grand Poobah
Joined: January-19-2004
Location: Portland, ME
Status: Offline
Points: 7948
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Posted: March-19-2008 at 9:09pm |
79nautique wrote:
yes I did, I stated basicly the same thing with out interducing my "theory" about what it should be. And you come back "based on what" bull***************,
based on common knowledge, based on reading the manuals in the past, based on what other stock motors run from the factory that I have riden in Timmy, so I wasn't specific enough for you soory it's because it was a general question with no set exact RPM because there are too many factors effecting what the RPM might be or should be at WOT.
guess next time I'll dig out a print out for you eastcoaster's to see the facts in black and white, but then maybe it wouldn't be the same print out you would come up with. | eastcoaster's
?????
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BuffaloBFN
Grand Poobah
Joined: June-24-2007
Location: Gainesville,GA
Status: Offline
Points: 6094
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Posted: March-19-2008 at 10:25pm |
Riley wrote:
eastcoaster's????? |
LOL
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1988 BFN-sold"It's a Livin' Thing...What a Terrible Thing to Lose" ELO
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79nautique
Grand Poobah
Joined: January-27-2004
Location: United States
Status: Offline
Points: 7872
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Posted: March-19-2008 at 11:50pm |
Let's not forget that even though it's less pitch, cup can add some of that back into the equation and also not every boat reacts the same to the same prop change. Ski Limes 540 experience comes to mind.
My .02 hammer down let it wind out, find the actual max RPM is now, then figure out exactly what the props specs are, then make a judgement call on how much to change the prop.
With the differences in the induction systems, your not comparing apples to apples so what worked good for you might not be so hot with less power driving it.
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05 210
Platinum Member
Joined: February-17-2006
Location: Southern Maine
Status: Offline
Points: 1481
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Posted: March-20-2008 at 12:56am |
Kristof wrote:
I'm enjoying yet another bashing LOL
I just went to the kitchen to get a beer and some chips... go on boys!!
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Chips just leave less room for beer.
No bashing in this thread,Kristof.Just two guys with their version of the facks.Love the boat,looks great!
What's an Eastcoaster?
Mike
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Barracuda
Moderator Group
Joined: November-17-2003
Location: United States
Status: Offline
Points: 998
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Posted: March-20-2008 at 10:44am |
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quinner
Grand Poobah
Joined: October-12-2005
Location: Unknown
Status: Offline
Points: 5828
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Posted: March-20-2008 at 12:08pm |
Eastcoaster would be a drink holder on your left, this of course does not play well with a right hand drive vessel.
Timmy, did you know 79' likes to be referred to as Chrissy?
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eric lavine
Grand Poobah
Joined: August-13-2006
Location: United States
Status: Offline
Points: 13413
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Posted: March-20-2008 at 12:13pm |
I hear the Europeons are poking at the Bin Laden Bee-hive....
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"the things you own will start to own you"
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JoeinNY
Grand Poobah
Joined: October-19-2005
Location: United States
Status: Offline
Points: 5693
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Posted: March-20-2008 at 12:34pm |
On the horsepower loss issue I don't concur with Petey's (sorry just following the mood) logic, the less BTu's per gallon would surely lead to less mileage per gallon but not necessarily to less horsepower if the gallon consumption increased. That should be relatively easy to accomplish since the propane is already a gas and doesnt need to be atomized to burn effectively. On top of that propane is considerably higher octane and therefore more timing advance is going to be possible without detonation. I would say a good tuner would take care of both of those issues. If it were me I would also deck the heads a bit as well to bump up the compression and hopefully that would get me about equal to preconversion numbers.
So anyway IMHO, he could easily be down 10-15%, but not necessarily.
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TRBenj
Grand Poobah
Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 21113
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Posted: March-20-2008 at 3:09pm |
79nautique wrote:
My .02 hammer down let it wind out, find the actual max RPM is now, then figure out exactly what the props specs are, then make a judgement call on how much to change the prop. |
Chrissy, I agree.
79nautique wrote:
With the differences in the induction systems, your not comparing apples to apples so what worked good for you might not be so hot with less power driving it. |
By different induction systems, are you referring to the propane or my top end mods? If youre talking about the propane possibly reducing the hp output, then the 470 turning more RPM will help (like Pete said).
If you mean my top end mods, my basis for comparison was when my engine was basically stock. The biggest difference would be in the hull, where the 2001 should be a touch faster (and turn maybe 100-200 RPM more). Still a valid comparison, IMHO.
My educated guess is that a bone stock 470 will work perfectly for him.
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79nautique
Grand Poobah
Joined: January-27-2004
Location: United States
Status: Offline
Points: 7872
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Posted: March-20-2008 at 3:24pm |
sorry you don't understand what all is in the induction sytem, so IMHO your in left field again and want to focus on a small section of the equation instead of the whole equation and when you do that you are not comparing apples to apples Timmy. That's why it always takes a ME to bail out a EE.
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TRBenj
Grand Poobah
Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 21113
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Posted: March-20-2008 at 3:34pm |
79nautique wrote:
sorry you don't understand what all is in the induction sytem |
If my interpretation of an induction system being the method by which fuel and air enter the combustion chamber is way off in left field, then please do explain the correct definition to me, oh great ME wizard.
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79nautique
Grand Poobah
Joined: January-27-2004
Location: United States
Status: Offline
Points: 7872
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Posted: March-20-2008 at 3:56pm |
how well did the 540 work on who's boat, and then there are the exhaust that didn't deliver, so there are several things that have been done with diferent results, some good some not so good, so saying because it did this to mine it's going to do the same to yours is horse***************. In an Ideal world it should but we are not in an ideal world and they are not apples to apples so why do you keep trying to make them apples to apples when it's clearly apples to oranges to most here.
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Hollywood
Moderator Group
Joined: February-04-2004
Location: Twin Lakes, WI
Status: Offline
Points: 13511
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Posted: March-20-2008 at 4:14pm |
two kiwis and a banana to two grapes and a string bean
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quinner
Grand Poobah
Joined: October-12-2005
Location: Unknown
Status: Offline
Points: 5828
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Posted: March-20-2008 at 4:18pm |
Hollywood wrote:
two kiwis and a banana to two grapes and a string bean |
So what you are saying is they are both a couple of fruits with string beans on the bottom end?
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Hollywood
Moderator Group
Joined: February-04-2004
Location: Twin Lakes, WI
Status: Offline
Points: 13511
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Posted: March-20-2008 at 4:25pm |
no, i thought we were talking about what we had for lunch today???
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TRBenj
Grand Poobah
Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 21113
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Posted: March-20-2008 at 4:26pm |
79nautique wrote:
there are several things that have been done with diferent results, some good some not so good, so saying because it did this to mine it's going to do the same to yours is horse***************. |
If youre trying to discredit me, those are some pretty weak examples- but I appreciate your attempt nonetheless.
Im not sure what youre getting at regarding the exhaust- the one person I know who lost hp with them was coming from a setup that was far from stock (and is NLA, by the way). Now thats what I call an apples to oranges comparison. Personally, I gained 400RPM in holeshot and 200 on the top over my stock manifolds, which I am very happy with considering I have a slow running hull.
Ive never claimed to be a 540 expert, as most of my experience is with the 1.23. I have only witnessed that prop run first hand once on a 1:1 2001, so clearly my word is not gospel with regards to that particular setup. How any of the older hulls will react are anyones guess- I can only point to the multiple testimonials given by the members here.
What I do know pretty well are the 1.23 props. Clearly, there will be variations in applications- no two hulls are exactly the same, nor is every single engine. Elevation, weight, water temps, application and other factors will all come into play. However, I have run more of these props than most, and am glad to share my experiences and opinions. Beyond that, Im not sure what else you expect to hear. Should I put a disclaimer in all of my posts?
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quinner
Grand Poobah
Joined: October-12-2005
Location: Unknown
Status: Offline
Points: 5828
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Posted: March-20-2008 at 4:32pm |
TRBenj wrote:
Should I put a disclaimer in all of my posts? |
Timmy,
That's a terrific idea, perhaps something like:
"two kiwis and a banana to two grapes and a string bean"
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tullfooter
Grand Poobah
Joined: March-02-2007
Location: White Lake, MI
Status: Offline
Points: 2225
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Posted: March-20-2008 at 4:41pm |
Hollywood wrote:
two kiwis and a banana to a twig and a two berries |
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Play hard, life's not a trial run. '85 BFN '90 BFN
White Lake, Michigan
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