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Originally Posted by Bottomfeeder
(Post 2036217)
Between 6 Illmors takin a s*** at Desert Storm and other issues I'm not a fan, in regards to the power loss @ high temps its a well known fact in the Lake Havasu area that from july thru aug you better re-prop and I personally lost 7mph, I called Illmor and I basically was told it was normal in our extreme temps 115 to 120 is the norm, I did a side by side comparison on 2 exact boats, 1 with an Illmor package and 1 with a 600 merc, the only advantage performance wise was rpm potential on the Illmor setup 6000 rpm/limiter versus 5375-5400 rpm on the merc 600, the merc had a much better midrange hit and I,m expecting my new 700's will clean up on the Illmor 700's in the same hull, fully bagged,carbon fiber/ kevlar layup in a 32 cat,,, IMHO
What I have noticed is the Ilmors show their true colors in the cats. Reason is cats propel off of peak hp numbers. The 700sciNXT or #VI package is a well developed package. I saw some early transmission probelms. In which Mercury Racing has taken care of. Just like anything keep on top of service and having an individual who knows the product maintain it. The Penske Ilmors have been good motors also. Food for thought. The 710 Ilmors have gone to stronger internals, why would they do that are they thinking about going blown for bigger hp #'s. However, complete packages are important in this business. Thanks, Cam-shaft. Hopefully you were able to read all of it. |
Originally Posted by Bottomfeeder
(Post 2036546)
I had a 07 38 Fountain with t-525's last summer and the port engine oil filter came loose @ around 5000rpm :eek: there was aprox 3 oz of oil left in that motor when I drained it and had it sent out for analylization, Merc says " run it and see what happens" this is 1 week before I go on vacation to Tahoe for 4 weeks .HOW WOULD YOU FEEL after spending 250k cash on a boat and 20k for my rental ?
On the other hand - it would probably have roasted any other engine.:D |
Originally Posted by Cam-shaft
(Post 2036571)
Just dealing with theories. The reason for the big power loss on bad air days is due to the 3.960 stroke and 9.6:1 cr ratio and no way to change that no matter what the barometric psi of the day is. I know the 710 ILmor is a 10:1 motor in which is one of the reasons for a higher rpm. What mercury racing has is a boost bypass control system. In which it can vary the boost psi on the MAP reading. Basically make better air for you on a bad air day (115-120 degree weather, altitude.) You have to look at where the peak hp numbers are. 5800rpm vs mercs 5300 on their 600sci. Spinning a motor past its peak hp number is usually not gaining any results other than telling you that you need more prop. This is why peak hp numbers are critical. However, you have to have enough torque to get you their. In which can vary on the amount needed from a cat vs a V-hull. What is the point of a 6000rpm potential if the boat is to heavy to get you their because the motor does not make enough torque or you have to put a prop on that is so small that it does not even make sense.
What I have noticed is the Ilmors show their true colors in the cats. Reason is cats propel off of peak hp numbers. The 700sciNXT or #VI package is a well developed package. I saw some early transmission probelms. In which Mercury Racing has taken care of. Just like anything keep on top of service and having an individual who knows the product maintain it. The Penske Ilmors have been good motors also. Food for thought. The 710 Ilmors have gone to stronger internals, why would they do that are they thinking about going blown for bigger hp #'s. However, complete packages are important in this business. Thanks, Cam-shaft. Hopefully you were able to read all of it. |
Originally Posted by Mentalpause
(Post 2036589)
I had that happen once - Merc warranty registered it in case something developed later from it. The computer saved the engine, no issues at all. I agree Merc's response is weak, and they abviously went through a period with QC issues in putting oil filters on. Seems pretty basic!:(
On the other hand - it would probably have roasted any other engine.:D |
Originally Posted by Bottomfeeder
(Post 2036570)
are you hitting the rev-limiters? who's got props? Dave ,,,I dont know?
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Originally Posted by Bottomfeeder
(Post 2036609)
I agree accept about the Illmors going to a blown/turbo application in a marine, high constant load application. How many alluminun block/4 stroke blown marine engines are out there for consumer use? The architecture on the Viper/Illmor marine block will not support the boost and heat from turbo/blower packages in a marine envirement that basicly a dyno run, its not the same game as a Hennesy Viper thats in the throttle for 10 seconds,,, IMHO :D
Thanks, Cam-shaft. |
Originally Posted by Cam-shaft
(Post 2036701)
Nothing said about a turbo. Maybe a centrifical. Internals is all I was speaking about. However, aluminum does work. Dis-reguard the name on the valve covers and look at the Donovan block.
Thanks, Cam-shaft. I know what Merc puts in there Blue motors for parts, does anybody know what Illmor uses ? Are they just marinized,cammed Viper motors or are they ground up custom builds? |
The Government has been using Donovan blocks since the early 90's. They did use closed cooling.
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