Cam specs for Merc 525 EFI?
 

Does anyone know what they are. They sound much different than the 500 EFI's, better.
JB

Lunati makes a cam part number 02005. It's lunatis version of cranes 525sc cam. It not a roller. I dont have cranes part number off hand but I have got it some where. The specs on lunatis are at ,.050" 224 and 234 with lift of .534 and .559 with a 114 deg sep.

Thanks Scarab but this is the new (EFI) 525.

sorry, my bad. Its possible that its the same cam it just sounds smoother because of the fuel injection. If any has the answer I would like to know also. I'm guessing its crane's 139741 roller cam.

due to the headers and increased compression would be a good guess.

More likely a Crane 16HR00004
298/306 adv, 236/244 @ .050, .610/.632 on a 114 LC

Thats the specs on the crane 168741. Probably just a different part #?Bob

The 168741 is on a 112° LC while the 16HR is on a 114°

Advanman- You could be right....but don't you guys think the upgraded heads and a true scavenging exhaust is worth more than 25hp, all things being equal [HP500 To HP525]?? The cam you guys are speculating is decent jump from an HP500. I would guess same cam and maybe even a little less on the exhaust because of the headers, say a 230/230 114 lsa??? Take Care Berg

i thought we were talking about sound??...NOT power.

Speaking of speculating, I do think that the improvements between the 500 and 525 are worth more than 20 HP - try about 65 HP...

If you put all the changes Mercury made to the 525 efi over the 500 efi into a computor program to determine hp, the new 525efi is closer to 575 than 525! I tried it.
JB

Okay then, let's talk about sound...John B. , are you talking about the quality of the idle? If so, I've never thought the idle of the HP500EFI was quite up to par, although, I think that motor is very nice.

It's not, but the 525 is HAIRY, from idle on up.

Then my vote is for the header theory....although the new Motorola & MAP setup probably improves the idle somewhat. Just asking, what is the compression of the new motor? Thanks, Berg

Advertised compression ratio of the 525 is 8.75:1 - a whopping increase of....0 over the HP500EFI

Wow, hardly seems worthwhile from a MFG.'s standpoint to upgrade to aluminun heads and not take advantage of a higher cr.

Adivanman- not doubting you, but where are you getting a 65hp increase? Seems like that kind of oomph puts this motor is too close to the 575efi sc!! This could be a marketing snafu that could upset some 575 owners!!!! How 'bout it Von Bongo?
Take Care, Berg

Estimated gain over 500 efi

Heads 40 hp

Headers 15 hp

Throttle body 10 hp

Cam "what is it?" + something

Anyone else??

lounge - it is closer to 570HP and yes, that is encroaching on the 575SCi's numbers. Shouldn't upset the 575 owners much though - their engines say 575 right on them...

575's make more power than 575. Probably closer to 650.

jd 1,

No way! Going from a 500 to a 525 is like a 4 mph increase. From 500 to 575 is a 6 mph increase.

This is from the boat manufactures' tests.

JB

The 500 makes approx. 500-505hp on a true steady state run on an accurate dyno. THe 525HP EFI makes 540-545hp with the same test. Compression is the same, same pistons, crank, rods, etc. The 575SCI makes between 600-605 with the same test. Mercury Racing is always conservative on power ratings while Mercury Marine is usually off. Typically there so called prop hp's are the crank hps, example, the 496Mag HO makes 415-430hp depending on computer cal. The 502 Mags made 415-420hp.

Thanks,
Dustin

Dustin, Thanks for the information. Back to the post.

DOES ANYONE FNOW THE CAM SPECS???

John.

John B,
Adivanman is correct. You can call Crane and they will verify P/N 16HR00004. I have a 525 HP and it is a very nice sounding cam, and still idles fairly well.

Thank you Hessdk,
Once again, specifications are:

Crane 16HR00004 BBC Hydraulic Roller
Duration (advertised) - 298/306
Duration (@ 0.050) - 234/244
Lift - .610 Intake, .632 Exhaust
Lobe Center - 114°

This is a purpose built marine camshaft.

Thanks guys,
I put this cam into a program ( Engine analyzer v3.0) and it showed a 10 hp improvement over the 500 EFI.

The specs just given above are a crane 139741

Actually, it's more like the 168741, except that the HP525 cam has a 114deg LSA instead of 112.

JohnB - Glad we could help.

Scarab________34,
Have you LOOKED at the specs for a crane 139741? Besides being hydraulic rollers and having the same lift the two cams don't share any specifications or applications. :rolleyes:

Rick232 - as mentioned before, you are correct.

Thanks for the info. Well that cam is bigger than I thought it would be, especially on the exhaust lobe! You would think since they are running a true header that they might back off of exhaust timing a bit in favor of cylinder pressure, especially since the cr is very conservative considering the aluminum heads. Maybe lowering cylinder pressures is their intent? They are the ones that have to warranty it. One thing for sure, the new Motorola ECM/sensors have it all over the old GM MEFIs'....making civilized big HP for this system a piece of cake. Take Care , Berg

You are right it is a 168741. My bad, I overlooked the lobe separation. But they do share silmilar applications.

ScarabMAN34, not to be confused with the female version. I had my name long before she did.

I give up....
 

Adivanman wanted to delete his original post here (a fairly sarcastic response to scarab____34) but thought better of it as it really did not have any technical relevance (I assumed that the original post was answered earlier). However, I find that I can no longer delete my posts without paying first. I guess that answers my question...pm's, avatars, signatures, what's next....