M104 Cylinder Head differences... - Page 5 - PeachParts Mercedes-Benz Forum

JayRash · #61 01-25-2010, 01:59 AM

As i see it, merc did improve the head, but any improvement they did was for better torque delivery lower in the RPM, ie better efficiency and less fuel consumption.
and if i was to chose between the 3.0 24 engine or the 3.2 M104 ill go for the 3.0, cause those new 2.8l and 3.2l tend to feel dead above 5500 RPMs, but i am sure its not a limitation in the head.

400Eric · #62 01-25-2010, 10:40 AM

Like I said before guys, they probably did other power robbing compromises to meet the more stringent emissions and fuel economy requirements and then got most of the power back with the improved, new head.

I would really like to see a more in depth study done on the older vs. newer cams. I am very sure that the newer ones are much tamer compared to the older ones than we have been led to believe. Wild cams and stringent emissions don't mix.

There were probably other power robbing changes as well. A good example of this is what happened to M119s and M120s starting with the 93 M.Y. (which is, incidentally, also the first year for the second gen M104). M119s and M120s lost their WOT fuel enrichment that year which caused said engines to lose 7 horsepower on paper but GSXR saw a 15 horsepower gain on the dyno when he switched his 95 E420 to a 92 400E ECU and I saw a over 2 tenths reduction in E/T at the track (on a warmer, higher D/A day to boot) when I switched my 93 400E to a 92 400E ECU. Since all of the V-8s AND V-12s saw their WOT fuel enrichment taken away after 92, there is every reason to believe that the lower in rank I6 M104 had it taken away too. (Obviously, switching ECUs is not an option for the M104 since there was that big CIS-E to HFM switch over that occurred starting with the 93 M.Y. but some will say that's what Megasquirt is for. Also, for the record, the AMG C36 had some, but not all, of that WOT fuel enrichment given back.) There may be even more power robbing things M.B. did that we don't know about. Thank goodness those new heads gave most of the power back.

Could somebody please translate that engineering paper? Again, I'll bet some of the answers we seek are there.
Regards, Eric

JayRash · #63 01-25-2010, 12:15 PM

ok i'm with u Eric on this one
but can u tell me why merc are so moody, like today a fairly cold day here with temps at around 12 C'deg
and engine temp around 80 yet the car felt like it lost some 30 hp over 4krpm? On the same tank of fuel on which was fine a day a go!
Its not the first time it has done this, go figure.

MAG58 · #64 01-25-2010, 08:06 PM

Quote:

Originally Posted by 400Eric

I would really like to see a more in depth study done on the older vs. newer cams. I am very sure that the newer ones are much tamer compared to the older ones than we have been led to believe. Wild cams and stringent emissions don't mix.

Define wild? If you'll read at the beginning I found duration and cam specs for both series. The later generation had only 4 total degrees less duration on the intake, identical on the exhaust. I also mic'd the lift and intake/intake and exhaust/exhaust are equal (give or take .002 for wear)

The first paragraph translated under "Developtment of the M104"

The innovation process of the engine M104
includes, starting from its predecessor
M103, two stages, each with
different job requirements.
In the first stage is the development
the M104 for the 300E-24 at the center. Its main
Characteristics, as a result of the first part of the
innovation process, are summarized in the table
and those of the M103 are compared. (Chart with engine specs)

The second stage was partially removing some of the Initial development.
Ecological requirements are at the forefront with a departure from pure performance. The new design attempts to reduce weight, noise, pollutant emissions, and protect materials by reducing friction. The Main measures to implement this are in the manifold. The best suited measure is to reduce speed as it reduces material costs and wear (? I think that's a close paraphrase). The table shows the rated speed for the 320E at 6300rpm (max power 162kw at 5500 rpm) maintained (constant). However, this is the maximum potential so high torque and high intermediate pressure (pe?) in the mid and low ranges are required. The practical application is getting higher acceleration from lower speeds.

Paragraphs 1 and 2
That took forever. Anywho, remember that it is common in engine mfg's to reduce port size on engines designed for torque at the bottom end to speed up port velocity and torque.

Max mean cylinder pressure (per engine)

M103 157psi at 4400
M104-24 165psi at 4600rpm
M104 177psi at 3750rpm

400Eric · #65 01-26-2010, 12:05 AM

Thanks for the translation!

If a port is designed correctly, you can reduce port size to speed up port velocity, and still see a gain in flow too. A good example of this is the good old Ford Cleveland. The heads that Bill Elliot kicked everybody's butt with in the 80s had smaller, raised ports compared to the original 70s versions.

Also, as I said in an earlier post, it's not just about how much air and fuel you can flow through the ports. It's also about what kind of condition the mixture is in when it gets inside the combustion chamber. Slamming the fuel/air mixture into that far port wall can cause some of the fuel to drop out of suspension leaving you with a poorly mixed, not very homogeneous mixture. This also appears to me to be another issue that M.B. was trying to address with the updated head. Now with a nice homogeneous mixture you have greater fuel efficiency, greater power, and cleaner emissions which I believe was what the engineering paper said was M.B.'s stated goals for the 2nd gen M104. So even if that later head doesn't flow as well as the earlier head does, it might still make more power anyway. (But for the record, I still think the later head does flow more because, again, the charge is being shot down through the valves, not across them. This means the charge has full access to all of the valve area, not just some of it.)

I'll bet most of the low end torque gain came from the trick new intake manifold.

Those max mean cylinder pressure numbers are very telling....
Regards, Eric

MAG58 · #66 01-26-2010, 09:11 AM

I'll agree with that. I'm re-working the CIS mani for efi and revised injector position, because it does mostly suck. Also the use of the newer Bosch high-impedance injectors should help as they have a much improved spray pattern as far as port injection goes anyways.

If I read most of those charts carefully, it seems that the intake mani on the 2nd gen model is much more suited to making the engine very torquey with it's large, constant diameter, long runners.

I think I'll keep my .980 for my Z, since I've always wanted a motor that could turn 8.5-9k (with some work), and I'll use my 2nd gen parts and 350sdl crank for a 190e.

I figure a 2200lb car doesn't need as much bottom end as a larger sedan.

JayRash · #67 01-26-2010, 04:25 PM

ok on my AMG 3.6 the intake cam is an AMG unit but the exh one is a stock 280 one and i would assume same as the 320 one as well but fitted with a modified sproket to give 4deg of retard.
So how does this cam compare to that on the 300-24 profile and lift wise. Would i gain any if i fit my sproket on it? Can the sproket be changed?

MAG58 · #68 01-26-2010, 04:40 PM

Quote:

Originally Posted by JayRash

ok on my AMG 3.6 the intake cam is an AMG unit but the exh one is a stock 280 one and i would assume same as the 320 one as well but fitted with a modified sproket to give 4deg of retard.
So how does this cam compare to that on the 300-24 profile and lift wise. Would i gain any if i fit my sproket on it? Can the sproket be changed?

As far as I can tell the 300-24 exhaust cam is the same as far as duration and lift, but retarded 1 degree (woah). The cam sprockets are different, as the front of the 300-24 is machined differently as it also drives the dizzy. However the sprockets are the same (width, teeth, etc.) so if you transfer the cam and sprocket together it should work. I'm not sure on ramp angles however, but given they're both hydraulic cams I'd imagine they're pretty close to the same.

Also, I think the AMG intake cam is just a Schrick unit, is this correct?

JayRash · #69 01-26-2010, 05:01 PM

ok so in the end ill end up havin the same cam, almost. As for the intake cam being a schrick one, i really can't say. But if so shouldnt we be able to find the exh at schrick as well. Would it give any gains worth its cost?

MAG58 · #70 01-26-2010, 05:05 PM

Quote:

Originally Posted by JayRash

ok so in the end ill end up havin the same cam, almost. As for the intake cam being a schrick one, i really can't say. But if so shouldnt we be able to find the exh at schrick as well. Would it give any gains worth its cost?

I'm not sure. To be honest, when I do it, I'm going with a mfg called Colt Cams. I personally contacted the owner and he has over 10,000 hydraulic profiles in stock. Since he has not done an M104 (but many M103's and 110's, and I think some 16v's) he will be the one analyzing the cam and telling us what profile we can put on our existing blanks. Unlike finger rocker type cam setups, lifter on bucket does alright with regrinds. He said the full regrind, finish polish, and parkerizing would be in the 500USD range for both cams unless we want them offset ground (one lobe opens slightly before the other to induce swirl) and that would be in the 600USD range.

I know dbilas and MKB both make M104 cams, but they're both in the 1000 euro range for ONE cam (you're still talking about ECE taxes as well on top of that). That's a little crazy in my book.

If you'd like to contact Colt, they can pretty much get you setup with something to directly fit your needs based on CR, Tranny, EFI, etc.

http://www.coltcams.com/html/contact-coltcams/index.cfm

JayRash · #71 01-26-2010, 05:14 PM

i am willing to fork for a better exh cam and even maybe a better intake one as well though i think the AMG one is good, but what do i know

really.
The main question now is would a new exh cam need any mods to the tune to make use of it. I would hate to spend such money and have nothing to show for.

But i am intersted in giving one of those cams a try.

MAG58 · #72 01-26-2010, 05:23 PM

That depends. A big lopey cam gives tons of top end, but it also usually lowers DCR which means mean cylinder pressure at the combustion event is lower. This means you'll get a small gain, but there is much left to be had. With a lower DCR you can run more timing on the top end without worries of pinging. Given the r/s ratio, the 3.6L is more prone to ping than the smaller motors. That said, MBZ probably left a bunch of timing out on the top end for that reason (as well as 400Eric's comment on fuel enrichment) a tune with a new exhaust cam will probably net some pretty substantial gains. I doubt that a 20hp gain (300+) would be that difficult.

Another thing to look at is the exhaust manifold. Though they split the manifold in two between the front and rear cylinders, it really hinders flow and scavenging in the high end of the power band.

JayRash · #73 01-26-2010, 05:44 PM

thnx for the gr8 input, i know i should consider some after market exh manifold as for cam's effets on DCR i am familiar with that too. I can up the timing on my car, thou i cant say how much more it is in numbers for i really dont know but i can tell u i can up it enough to the point that even with full retard by the knock sensors i managed to cook my head gasket, and i u can hear the ping.

I can up timing from mild to all the way to till u hear the ping at full revs. Prob is its a full offset to the whole original map as is.
btw when i do up the timing the car really shows like at least an extra 10hp top end and the mid range at around 4k rpm really shines. So my guess is with a new exh cam and manifold and my trick for the timing we can see a solid 300hp+ from this engine.
Worth a try.
Ill check that link tomorrow as its almost 1am here and am using my phone to post. Ill get back to u then.
Thnx again.

MAG58 · #74 01-26-2010, 11:39 PM

For what it's worth, I just checked the dBilas website, and they did list two separate cams for the .980 and other model M104s.

Interestingly, the biggest cams offered (sport) are in/ex 258/262 with about 400 thou lift at the valve (10.2mm) usually their sport offerings seem to be more in the 270 deg. duration range, sometimes up to 282's (they make 316's for the 16v

). Perhaps M104's don't need it?

The later model offers a little larger duration on the intake side at 262's for both sides, still at 400 thousands lift. Both of these cams are listed at 700euro for the intake cam and 667 for the exhaust cam.

MKB does not list their cams on the website, but if you email them, they will give you their specs.

Edit: I just checked my emails, they did not list duration, but MKB produces cams in 10.3 and 11mm lift, however each one will set you back 1375 euros.

I wonder if there is a place to get M104 cam blanks? I could make some really wild cams then

Edit2: I just emailed renntech. I'll probably have to mortgage everything I own to just get a quote out of them, but hopefully they will also have a solution.

JayRash · #75 01-27-2010, 01:29 AM

Or maybe M104's can't make use of wild cam of 270+ duration :S too many ristrictions maybe, in the manifolds, head, TB....

so how can i know what i have on my AMG 3.6? i really have no idea. whats the lift on out cams? and does the intake one on the AMG have more lift?