liquid lounge

Mark, how ya been man?
Nothing wrong with the manifold at all when used in the rpm range those long runners were desingned for. The problems with modifying these engines is that people think you can just build them and then just have the ecm re-cal'd ,just dosen't work that way: the heart of any speed density efi is the MAP sensor...when this sensor dosen't get a stable reading, drivability rapidly declines...increased overlap diminishes the MAP's ability to get a good reading. When I said that cam/manifold combo was already on 'the ragged edge' it means that there's enough overlap already causing the MAP to get less than ideal readings...leading to the HP500 efi's less than perfect idle, gas dilution of the oil, and dirty transoms...I'm not saying it's a major problem now, just that it goes down quickly from there. What do you want to bet the new 525 has less duration on the exhaust? The new heads w/ better exhaust ports and true scavenging exhaust are all about decreasing overlap by decreasing exhaust valve timing leading to an efi that works better...the extra 25 ponies are just an expensive bonus. Did you know that the guy who designed the HP500/HP525 efi manifold will reccommend a smaller cam than the 230/236 Merc used in the 500 if you buy the same set-up from him? He told me that 224/230 is about ideal....somthing to think about, huh?
To Mark and others: Sorry this didn't get threaded with the original post about "cast iron heads..." please move back if you or a moderator can. Take Care

KAAMA

iTrader: (1)

Thanks Lounge----that's very interesting for sure! A few years ago most people told me that my cams are too small (236*/244* @ .050") for my 540's. I was going to go with some even smaller cams yet, but it didn't work out that way. When it comes to cams and carbs I usually try to "err"....on the smaller side of the spectrum. I was asking about the 500EFI because I know of a few friends with them that were possibly thinking of some mods, but I don't how far they want to go with them.

Bobby Daniels, I think you and blown1500 mentioned something like he upgraded a pair of 500EFI's and got about 630hp or so out of them---right? So what you are saying is that you can actually get 600+hp out of a 500EFI while utilizing the stock Merc EFI intake, Merlin heads, cam and reprograming the computer and still have good reliability and drivablility? Lingenfelter could only get 540hp or so out them----of course I don't know what all Lingenfelter did to them and this was about 2.5 years ago, but Lingenfelter's shop basically told the guy that it was the most they could do without RADICALLY changing the engine or completely starting over with a new engine and John Lingenfelter is super intellegent and highly respected when it comes to fuel injected stuff.

I am getting CONFUSED and need some insight and understanding on this 500EFI issue so I can set my friends straight. HELP!