Indmar 350 hp really 308 hp?

[eyepeeler]

Here is an interesting thread regarding Mastercraft's switch to Ilmor.

http://mastercraft.com/teamtalk/showthread.php?t=40397&highlight=ilmor

[shawndoggy]

Not to mention Malibu fibbing on top of Indmar's ratings....

http://www.themalibucrew.com/forums/index.php?/topic/30583-solve-a-mystery/page__p__441041__hl__wakesetter67__fromsearch__1#entry441041

[Bu hoo]

Im not much of a mechanic, but my understanding of my Indmar Monsoon 320 is that it is just a 5.7l small block. The base gm small block is only rated for like 270hp. Im not sure where Indmar/Malibu comes up with the additional hp. Maybe its the exhaust, mpi and such.

If someone knows how all this works I would enjoy getting some education on the subject. Do they change the cam, cylinders or anything like that?

Edited May 13, 2011 by Bu hoo

[SmoothWaterMan]

The Monsoon and the MCX are not necessarily the same power, especially if it was "detuned" as stated. But, keep in mind who is stating those facts - Mastercraft - who is changing over to all Ilmor products and wants to encourage all their customers to go that route. It's a smart business decision on MC's part.

Regarding power, the guidelines are an engine mfg has a 10% leeway in published numbers, to accommodate variances in production engine power output. This allows for an auditor to grab any engine at random and it must produce within 10% of the state horsepower. It can be up to 10% high or 10% low. With the sequential MPFI and tuned intakes and exhaust manifolds it's gotten very hard to every tell a difference, but in the older days of early EFI or carbs you could really feel a "good" engine from a "standard" engine.

But, in the grand scheme people, and therefore manufacturers, put too much emphasis on marine "horsepower". Unless you are referring to boats running in the triple digits, the proper comparison would be the torque numbers and curve.

To date, and by the opinion of many, I believe the Monsoon to still be the best torque producing engine in the skiboat industry through it's entire range. There are few engines, and none in it's class that I am aware of, to produce what it does off idle.

Peter

disclaimer : I have not been able to test the Ilmor engines yet.

[sp0tts]

The Monsoon and the MCX are not necessarily the same power, especially if it was "detuned" as stated. But, keep in mind who is stating those facts - Mastercraft - who is changing over to all Ilmor products and wants to encourage all their customers to go that route. It's a smart business decision on MC's part.

Regarding power, the guidelines are an engine mfg has a 10% leeway in published numbers, to accommodate variances in production engine power output. This allows for an auditor to grab any engine at random and it must produce within 10% of the state horsepower. It can be up to 10% high or 10% low. With the sequential MPFI and tuned intakes and exhaust manifolds it's gotten very hard to every tell a difference, but in the older days of early EFI or carbs you could really feel a "good" engine from a "standard" engine.

But, in the grand scheme people, and therefore manufacturers, put too much emphasis on marine "horsepower". Unless you are referring to boats running in the triple digits, the proper comparison would be the torque numbers and curve.

To date, and by the opinion of many, I believe the Monsoon to still be the best torque producing engine in the skiboat industry through it's entire range. There are few engines, and none in it's class that I am aware of, to produce what it does off idle.

Peter

disclaimer : I have not been able to test the Ilmor engines yet.

Great post, like the old saying goes, horsepower sells cars, torque wins races. If anyone reads that MC post take note it says "they detuned it that much so that the Ilmor will be more appealing." Seems like there are a lot of assumptions in that thread. Bottom line, I know the monsoon can do everything I need it to

[WakingMeHappy]

Great post, like the old saying goes, horsepower sells cars, torque wins races. If anyone reads that MC post take note it says "they detuned it that much so that the Ilmor will be more appealing." Seems like there are a lot of assumptions in that thread. Bottom line, I know the monsoon can do everything I need it to

Agreed. Call my engine whatever you want but this boat serves me and my family very well. If Indmar or Malibu made a mistake or they're doing something shady then they should correct that. But we're reading a forum post for the facts. Can't always say that's the best expert advice. As for my 12 year old boat...doesn't matter.

[Ndawg12]

The Monsoon and the MCX are not necessarily the same power, especially if it was "detuned" as stated. But, keep in mind who is stating those facts - Mastercraft - who is changing over to all Ilmor products and wants to encourage all their customers to go that route. It's a smart business decision on MC's part.

I'm not sure I agree with that. What is that saying about the thousands of boats they put Indmars in and their current customers? Falls right in line with what I would expect from MC though.

[Bu hoo]

I would like to add that I am totally happy with my engines performance. I was just interested in how the ratings are compiled.

[eyepeeler]

As a 210 lb slalom skier at 38 off, I want ALL of the power that I can get. I have a 325 Monsoon but I have skied behind a Hammerhead and loved it when most skiers think it is too strong of a pull. Mastercraft and Correct Craft both have gear reduction. Malibu does not, so for me, I need every hp.

[hethj7]

As a 210 lb slalom skier at 38 off, I want ALL of the power that I can get. I have a 325 Monsoon but I have skied behind a Hammerhead and loved it when most skiers think it is too strong of a pull. Mastercraft and Correct Craft both have gear reduction. Malibu does not, so for me, I need every hp.

FWIW, gear reductions do not change an engine's horsepower. At the shaft, you may lose a few more hp due to friction losses in the gear, but the engine output remains the same.

[Devin Perry]

FWIW, gear reductions do not change an engine's horsepower. At the shaft, you may lose a few more hp due to friction losses in the gear, but the engine output remains the same.

He is just saying that gear reduction can make it feel like you have more power/stronger pull. But malibu does not have reduction so the extra power is a welcome addition.

[hethj7]

He is just saying that gear reduction can make it feel like you have more power/stronger pull. But malibu does not have reduction so the extra power is a welcome addition.

Got it

[eyepeeler]

He is just saying that gear reduction can make it feel like you have more power/stronger pull. But malibu does not have reduction so the extra power is a welcome addition.

Thank you for clarifying.

[tvano]

FWIW, gear reductions do not change an engine's horsepower. At the shaft, you may lose a few more hp due to friction losses in the gear, but the engine output remains the same.

back to that torque discussion, that gear reduction produces a torque increase.

[shawndoggy]

back to that torque discussion, that gear reduction produces a torque increase.

But isn't it all washed out with the prop? Gear reduction = "taller" prop, no gear reduction = "shorter" prop?

[Bill_AirJunky]

I'm not sure I agree with that. What is that saying about the thousands of boats they put Indmars in and their current customers? Falls right in line with what I would expect from MC though.

Maybe it's a good decision because (as I recall) both MC & Ilmor are owned by Penske?

I had an interesting conversation with Adam McCall (Mr Axis boats) this year at the Spokane Boat Show. I commented on the new G3 tower & how troublefree Titan towers have been for our group (compared to the other option which has been very much troublesome for people I've known). The topic got to engines & he said that the Monsoon is basically the Titan of inboard engines..... troublefree, long running, great performance, etc. Why else would Malibu have run it for so long?

[Ndawg12]

Maybe it's a good decision because (as I recall) both MC & Ilmor are owned by Penske?

I had an interesting conversation with Adam McCall (Mr Axis boats) this year at the Spokane Boat Show. I commented on the new G3 tower & how troublefree Titan towers have been for our group (compared to the other option which has been very much troublesome for people I've known). The topic got to engines & he said that the Monsoon is basically the Titan of inboard engines..... troublefree, long running, great performance, etc. Why else would Malibu have run it for so long?

I thought MC was claiming that there was a discrepency, my bad.

[Woodski]

Im not much of a mechanic, but my understanding of my Indmar Monsoon 320 is that it is just a 5.7l small block. The base gm small block is only rated for like 270hp. Im not sure where Indmar/Malibu comes up with the additional hp. Maybe its the exhaust, mpi and such.

If someone knows how all this works I would enjoy getting some education on the subject. Do they change the cam, cylinders or anything like that?

The basic marine long block GM uses does not have the same camshaft as the standard base 350, the marine cam is a specific grind for marine needs. The base GM small block rated at 270 hp is a different configuration, specifically the cylinder heads, pre Vortec to post Vortec heads introduced in 1996. Today there are several base engine options to choose from to allow the marinizers to offer different packages. You can go through the GM Performance Parts catalog or website and see what the power output of the various engine offerings is. The base content remains the same as the marinizers add the ancilliaries such as the exhaust manifolds, raw water pumps, etc.. Those additions can make a difference in ultimate hp/torque levels. The marinizers do have to ultimately certify the offering.

[MARiley]

mastercraft's switch to ilmor is completely irrelevant, until they start offering this in their boats:

[FIC]

Hp of boats is gross HP which means rated at the crank on a dino, cars and trucks is net HP rated at the wheels ,this was a govorment mandate, and was said earler torque is what makes the boat move from a dead start.

A good comparison is the 6.0l 400hp and the 6.2l 400hp , the stroke of the 6.2l makes it easyer to pull alot more load in a wakeboard boat yet both are 400hp.

[SmoothWaterMan]

I'm waiting for some smart guy to take my ideas off paper and put it in a direct drive. Plenty of hurtles, but think about an ultra low profile motor box with an IO-720 under it.

Lightweight, might even be a mate for a futuristic Response LXi V-drive powerplant.

Lycoming IC-720

Peter

[rennis]

Hp of boats is gross HP which means rated at the crank on a dino, cars and trucks is net HP rated at the wheels

Net HP does not = wheel horsepower. No cars are rated at the wheels.

[Tims]

I'm waiting for some smart guy to take my ideas off paper and put it in a direct drive. Plenty of hurtles, but think about an ultra low profile motor box with an IO-720 under it.

Lightweight, might even be a mate for a futuristic Response LXi V-drive powerplant.

Lycoming IC-720

Peter

That would be the ultimate bullit proof engine for a boat if you could figure out a way to keep it cool. Those engines require a huge amount of directed cooling air.

[Jimmypooh]

I'm waiting for some smart guy to take my ideas off paper and put it in a direct drive. Plenty of hurtles, but think about an ultra low profile motor box with an IO-720 under it.

Lightweight, might even be a mate for a futuristic Response LXi V-drive powerplant.

Lycoming IC-720

Peter

RPMs are under 3K. You'd need a huge prop on that thing.

[jkendallmsce]

FWIW, gear reductions do not change an engine's horsepower. At the shaft, you may lose a few more hp due to friction losses in the gear, but the engine output remains the same.

The HP, and TQ for that matter, is the same whether it is 1:1 or reduced. The difference is that the pull was more consistent with the gear reduced boats a few years ago.. But with the higher output engines, boats nowdays have 350-400+ ft# of torque...which is enough for consistent pulls.

When you get big guys into short line lengths. I know the added HP and TQ has helped a lot of skiers get to the next line length. Just as PP has saved many a marriage for course skiers.