M104 Cylinder Head differences... - Page 4 - PeachParts Mercedes-Benz Forum

JayRash · #46 01-21-2010, 01:58 AM

NAM sure did not get this engine. It was such a rare engine anyways and if it has the older oval head ports it must have been CIS then.

BTW early W140 also got the M104 3.0-24, but it came with EFI and made 11 extra HP with the total being 231hp, it also lost 200RPMs from the redline ie redline was 6800 io 7000.

400Eric · #47 01-21-2010, 02:25 AM

Quote:

Originally Posted by JayRash

[/U]

I still say this is a superior approach to the valves than the earlier head has.
Regards, Eric

MAG58 · #48 01-21-2010, 02:49 AM

You're also looking at a port that's about 1-2'' longer than the earlier port (sans intake). No clue what these two will flow with the intake when put on a flow bench. I must find out!

JayRash · #49 01-21-2010, 03:14 AM

Quote:

Originally Posted by MAG58

You're also looking at a port that's about 1-2'' longer than the earlier port (sans intake). No clue what these two will flow with the intake when put on a flow bench. I must find out!

My money is on the longer intake port, thou if ur planning to boost the engine the short port will work better since it wont reach sonic speed as quickly.

I mean to say on an NA the long port to the valves will help accelerate the intake charge helping both mid range and top end. the shorter wider port will flow at lower speeds, thou it might acctually work better at real high RPMs. this lower speed is a plus in boosted engines, but we r considering that you will be reaching either head's flow limits.

MAG58 · #50 01-21-2010, 03:18 AM

Quote:

Originally Posted by JayRash

My money is on the longer intake port, thou if ur planning to boost the engine the short port will work better since it wont reach sonic speed as quickly.

I mean to say on an NA the long port to the valves will help accelerate the intake charge helping both mid range and top end. the shorter wider port will flow at lower speeds, thou it might acctually work better at real high RPMs. this lower speed is a plus in boosted engines, but we r considering that you will be reaching either head's flow limits.

I'm not quite sure that's my point. The longer point will provide more uniform flow without the intake, but basically what I'm saying is the newer port seems to be something akin to taking about an inch or two off the origional intake and casting it into the head. I want to know how these heads perform with some runners bolted up, as that's how they're going to run. Flowbenching a head with now intake on it is mostly pointless, IMO as no gas burner I know can just run with open ports into the environment!

JayRash · #51 01-21-2010, 03:35 AM

Quote:

Originally Posted by MAG58

I'm not quite sure that's my point. The longer point will provide more uniform flow without the intake, but basically what I'm saying is the newer port seems to be something akin to taking about an inch or two off the origional intake and casting it into the head. I want to know how these heads perform with some runners bolted up, as that's how they're going to run. Flowbenching a head with now intake on it is mostly pointless, IMO as no gas burner I know can just run with open ports into the environment!

We cant really compare the length of intakes between CIS and EFI. if u look at the EFI one u will see its got even longer runners than that of the CIS, and by some margin too, and then there is the extra length in the head ports. I know for a fact those longer intake runners of the EFI manifold help in low down pull, but how would they perform for the top end? A compromise I say.

400Eric · #52 01-21-2010, 05:10 AM

Short or long port, boosted or not, high RPM or low RPM, it's all about the approach to the valves. There is a reason M.B. spent time, effort, and money to research, create, retool for and put into production the raised port heads to replace the first gen. M104 heads when the first gen M104s were only three friggin years old. There is a reason all newer performance oriented engine's ports are placed high and getting higher compared to the "good old days". Take a look at the "new" "Coyote" V-8 Ford is releasing as we speak.

Interestingly, The M119, which is a year older, went from CIS-E to LH to Motronic, from 1989 through 1998, a ten year run, with no change in it's head or port design. Car companies don't spend money unless they are forced to by competition or regulation or both. Old man Ford finally replaced the Model T only because competition forced him to. They'd still be selling those things today if they could have gotten away with it. M.B. replaced that only three year old head for a reason and it wasn't just for emissions.

The "new" Coyote V-8, which, despite what Ford would have you believe, is really just a new set of heads on the old "Mod" engine, is being rushed into production only because the Mustang is now, once again, the slowest pony car out there. Just like in the old days when they created another "new" pair of engines, the Boss and the Cleveland, which was again, basically just a new set of heads, to get themselves competitive again. It's not something any car company likes to do unless they have to.

You've got to remember that Lexus came out of nowhere in 1989 and almost immediately began causing serious misery to M.B. and BMW.

Again, the older head is shooting the intake charge across the valves, the later head is shooting the charge down through the valves. 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 somebody said 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'm sure many of the answers we seek are in that German engineering paper. We need a translation!

Regarding the intakes, are we forgetting that the later intake has a valve that switches the intake between a low RPM torque mode and a high RPM power mode?

And yes, I agree that the flow tests should be performed with the intakes in place. Just be sure to test the later intake in both of it's modes.

What you have here is two guys telling you the later engine is better. One guy who owns one, and another guy who just had his 400E's butt kicked by one at our most recent dragstrip day.

Regards, Eric

JayRash · #53 01-21-2010, 06:37 AM

I really would love to see flow results for both, especially the later one with both modes of the resonance flap.

to tell u the truth, i think both heads will surprise us with how good they r. I know the M103 head really flows, as Roman (Pumpsih) can confirm, for it generates serious power on fairly little boost. and the turbo that u think is good for say 350hp on a 2l 4 cyl, will barely have enough puff on an m103 to provide proper topend flow.

I was on the phone with roman few months back asking abt a turbo i wanted to fit on an M103, i recall he told me that the merc heads out of his own experience flow well and will need a large turbo to cover its needs.

400Eric · #54 01-21-2010, 06:48 AM

Oh yeah, I'm sure the early heads flow great. But I'm thinking that the later head flows even better.
Regards, Eric

MAG58 · #55 01-21-2010, 12:32 PM

I'm here to tell you that the picture of the .980 head is deceiving. I'm not saying that it does or doesn't flow better, but I am saying you cant just look at the pictures and tell (I was hoping someone has some kind of figures between the two).

I can tell you this. After sitting the two heads side by side on my garage floor and looking at them, the port floor on the .980 head isn't as poorly radiused as it looks in the pictures, and with the intake on, the flow path is MUCH more similar to the newer head than in the pictures as far as total flow is concerned. I'm also saying that if you machined second gen head flat to the side of the head like the .980 has and not like how it came from the factory, the two would look almost identical. On the later head, the Injector angle Is not that fantastic. You're so adiment about the charge air going through the valves, but if you bolt the intake up to the head, the injectors are aimed at the back of the port wall.

There are way more differences to these heads past that of a simple intake port shape and I'm quite willing to bet that emissions and the cost to produce the head are going to be BIG in this design. You have to remember that in the early 90's, right when the 1st Gen M104 came out, there were quite a few wide sweeping emissions control changes and it's probably very likely that the early model head even with EFi would have been incapable of meeting these regulations. On the other side of the world, there were quite a few engines that never made it to the US shores from Japan just for this reason.

Do I think the later head is going to flow better? Most likely. But it's irresponsible to out and out discount the early head when it produced the same power as the later motor with a sad CIS system, a dizzy (which just cant provide the spark accuracy) and 200 less CC's.

400Eric · #56 01-22-2010, 03:26 AM

It's not the pictures that convinced me the later head is better, it's the fact that M.B. spent the time, effort, and money to replace a head that was only three years old. This means they would have had to begin work on the new head almost as soon as the first one was put into production! Another thing that convinces me of the superiority of the later head is the fact that if it wasn't superior, we wouldn't even be talking about a 2nd gen head because M.B. wouldn't have put it in production if it didn't produce results. I'm only using the pictures to show how I think it's superior.

I don't see any difference between the two heads that screams: "The newer head is cheaper to produce!"

I did say it before, that 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 head.

I don't think M.B.'s switch away from CIS-E gained them much horsepower because the 5.0 M119 didn't gain even 1 horsepower when it ditched CIS-E. Remember, the M119 did not get a new head design when it switched F.I. systems. Actually, it never got one at all. It also didn't gain any horsepower or torque when it went distributorless.

I agree though that CIS-E going bye-bye was a good thing. Another example of car companies not changing or improving unless forced to.

I beg to differ about the aim of the fuel injectors. The trajectory of the fuel coming out of the injectors is towards the near side, not the far side. Actually, an injector working properly has a wide spray pattern that covers a large area of the port/valve. There is also a designed in split to the pattern towards both valves if the injector is operating correctly.

Like I said, I just want to see you put your efforts, talent, and money towards the M104 that will give you the best results because I, like you, would like to see this engine get some much deserved recognition.

Please let us know the results of the flow tests.
Regards, Eric

JayRash · #57 01-22-2010, 04:06 AM

On a side note guys, CIS isn't as bad as most think it is. My W124 300 M103 has not had one part of its CIS system changed except for a set of new injectors and th usual fuel filters. The car even went thru to get boosted on the CIS system with no additional injectors, then back to N/A. It still drives like the day i got it even after almost 400000km.

And my car made a DYNO proved 200+hp from a 12valve M103 with CIS. which is really gr8, so is fuel eco when in N/A.

I know it wont come close to having an EFI in terms of control, but at least up until yr 1995 its was close enough.

I bet u if u bolt a 3.6l M104 in place of the m104 300-24 block, and even with CIS, it will still make close to what my AMG is supposed to be rated at from factory.

400Eric · #58 01-22-2010, 04:58 AM

I'm already on record that I believe the reliability of the CIS-E is better but squirting fuel constantly at intake valves that are closed 75% of the time is not the recipe for good economy or low emissions. That is why Benz finally had to replace it.

My 4.2 LH M119 gets me the same 20 MPG as my two 3.0 CIS-E M103 cars do despite being over 25% bigger and despite making over a hundred more horses and over a hundred more foot pounds of torque. Yes there are other factors at play in that comparison but still the bottom line is, again, M.B. wouldn't have changed from CIS-E if there wasn't a benefit to it.

I still dearly love my two M103 cars but you'll notice that I'm also trying to find them new, loving homes. (Which I'm afraid is never going to happen because my screening process is too rigid.)
Regards, Eric

JayRash · #59 01-23-2010, 03:58 AM

Here is a pic of the exhaust side of the AMG Head. If i am not mistaken, for i found it among the hundreds of pix i have abt all sorts of cars and engines :S

M104 Cylinder Head differences...-20090918_125512.jpg

MAG58 · #60 01-24-2010, 03:42 PM

But for the 3.2L, using the same CR, using cams that are damn close, it produced the same power! Sure it was a little lower in the rev range, but it did have 200cc's bolstering it as well. You think MBZ spent a load of cash to re-design the head thus it obviously has to produce more performance, but why would they spend that much money and make THE SAME hp? I don't think performance potential, in terms of "oh this head will be easier to make more power so we're helping the aftermarket", was really considered all that much.

Again, I'm not saying either is better at the moment. I just don't think it would be wise to count these heads out. There's relatively few of these heads around, might as well port the crap out of it.