Ilmor High-Performance unveils MV8 570 Small Block
04-27-2012, 06:50 PM
#161
I'm with you on this one. I know what my boat averages. I go out and run 250 miles and burn 160 gallons = 1.56mpg. And I cruise at 100 - 110 mph the majority of the day. My pair of 588s burn the same amount of fuel as my old 3.0L 300hp outboards did on my 28s - which I cruised at 80 - 90 mph the majority of the time. Certainly, at the same throttle setting, an LS7 will burn less than my 588s. However, because my boat is geared/propped for greater speeds and has more torque, I am at a lower throttle setting to go the same speed, thus NOT burning more fuel. What I think most people here do not understand is that mpg has a lot to do with hull/drive/prop efficiency, not just the motor. And I agree with a lot of comments on this thread that the LS7 can be a very good performance engine, just not in the upper echelons of performance or larger boats. I think they'd be great in the under 30' / under 120 mph market - which is 90% of the performance boat market anyway.
04-27-2012, 07:06 PM
#162
Registered
I'm with you on this one. I know what my boat averages. I go out and run 250 miles and burn 160 gallons = 1.56mpg. And I cruise at 100 - 110 mph the majority of the day. My pair of 588s burn the same amount of fuel as my old 3.0L 300hp outboards did on my 28s - which I cruised at 80 - 90 mph the majority of the time. Certainly, at the same throttle setting, an LS7 will burn less than my 588s. However, because my boat is geared/propped for greater speeds and has more torque, I am at a lower throttle setting to go the same speed, thus NOT burning more fuel. What I think most people here do not understand is that mpg has a lot to do with hull/drive/prop efficiency, not just the motor. And I agree with a lot of comments on this thread that the LS7 can be a very good performance engine, just not in the upper echelons of performance or larger boats. I think they'd be great in the under 30' / under 120 mph market - which is 90% of the performance boat market anyway.
Im in a different league speed wise, but notheless have my own set of issues regarding fuel.
Im considering a repower to 2 of these Ilmors from a single Ilmor 710
That should be easier on my drives and click out a pretty close if not over 100 MPH (the MAGIC number) for regular guys like me with little V hulls.
With a single 710 in a 28 footer it runs pretty fast for what it is and gets really good economy and I can go from Marina Del Rey to San Diego in under a tank right now at a good clip on the ocean.
I can get anywhere from 2.0 to 3.3 MPG now, and I'm worried my cruise consumption will force a fuel stop going forward where now I am a "direct flight".
UD
04-29-2012, 09:54 AM
#165
Registered
IlmorDude, I know you can't give away any proprietary info, but can you fill in some of the blanks for us. Does your new 570 use the tall deck LSX block or the standard height LSX? Also what heads are you all using (cathedral, LS3's, LS7's) and are these getting any port work done (or are they the GM Performance Parts CNC'd heads)? Also are you guys getting the displacement the same as GM (4.185*4.125)? Lastly I noticed this in a previous post, "Camshaft advance is progressive through 25 degrees (50 degrees crank timing), with full advance at 4400 rpm"? Is this accurate or is someone getting the ignition timing confused with the cam timing. Not 100% familiar with how the VVT works other than knowing it alters the cam timing, but I would not see you wanting more than about 10 degrees or so of variation in the cam timing and I would think you would advance the cam timing down low and then retard the cam timing as the RPMS increased. At least that was how we used to do it in the old days. Advance the cam to bring the tq curve down lower or retard the cam to help it make more power higher in the rpms, has something changed?
