After a year of ownership and lots of thinking, I want to go to town on really modifying the engine and drivetrain (in conjunction with suspension + brakes; these I have figured out already).

A couple of things before I start....

- Please dont tell me my car will never be as fast as an SRT6, as I know it never will be
- Please dont tell me my car will be nearly unsellable once I'm done, I have no doubt that's the case

The reason I want to go down this route is to learn. I've been tinkering with cars ever since getting my provisional, but have always been fearful of working on anything beyond valve cover gaskets/plugs/wires and standard service items (oil changes/filters/coolant/belts etc).

Hope that doesnt come across as rude, just wanted to get that out of the way before cracking on

So, what I'm really looking to do identify the performance modifications I can make to my engine and drivetrain without going forced induction. The reason for this is the m112 is notoriously hard to force induct (heat issues/space issues/requirements for fabrication of mounts etc) and to be honest, I would like to go down this route - after taking care of other aspects first. I dont have the skills or knowledge to competently do a forced induction build without messing something up big time.

My car currently has:

- Cat back exhaust (rear cats removed, primaries in place)
- 3'' dcai running into the C320 airbox, K&N air filters to a 3'' MAF and 74mm TB
- E55 engine mounts (to reduce engine flexing as I read the M112 uses the mounts to reduce rotational inertia introduced by the balance shaft)

And a few minor things that arn't worth mentioning (sprint booster for example).

These are all pretty cheap bolt-ons. A few things spring to mind on how to get further gains:

1) port/polish the head
2) Fit 3-2-1 exhaust headers
3) High-flow cats (still trying to asses if these are even worth while to be honest, I'm curious if they will help more so because the cats are 10 years old vs being actually 'high flow)
4) Larger injectors (need to investigate cycle performance of the current ones, reading that at this point they are at max)
5) Further cool air intake (no idea how, need to figure out)
6) E55 fuel pump
7) ECU tune!
8) Karmaan camshafts

The thing is, this is all simple bolt on stuff. Does anyone know of any other mods that can be applied to the M112? Apparently the internal are forged already, and researching online brings up jack all!

The car may even end up slower than an NA but I'll learn a lot.

 

My two bits :
1,3,5,7,8 should help.
2,4,6 no advantage.

7 for sure !
I have read studies stating the a CAI is a waste of money, others stating that a small performance gain is possible due to the lower IAT's.

exhaust mods have not shown any real ROI, intake mods do seem to add some torque and HP.
As far as the fuel flow, it is completely adequate on an NA, it's when you get into the higher boost numbers on the SRT6's that you need to look at fuel flow ( Air Fuel Ratios )

The VERY BEST performance mod on an NA is to drop in a V8, but this requires some expertise on the electronics.

 

Thanks for a fast response!

This is where I want to really focus my research.

All the evidence seems to suggest (from what limited research I've done, with much more to follow!) that the exhaust system is adequate for the numbers the car puts out. But, on the exhaust cycle, if there is an increased amount of gases coming ouf of the chamber (due to increase air/fuel being combusted) then I would have thought that the requirement for a free-er flowing exhaust is needed.

The problem is, I dont know how to measure this to find out if its true or not.

One of the other areas I'm looking to identify is what further changes can be made to the M112; I've spoken to a couple of reps at Karmaan who are quite tight lipped about what can be done, beyond suggesting their sports camshafts of course

 

The throttle body upgrade is cheap.
Used from low milage donor $50-$60
New maf housing $20

 

90MM?

74MM I have fitted already.

I'm unsure how to mate the 90mm to the engine intake. Securing the air intake is another concern.

The other side is that if the engine intake is only 74mm then what benefits will there be to trying to force a 90mm to mate to it?

Things I need to work out; quite new to this side of things - mechanics I'm not new too, but usually following others instructions/steps.

 

The answers that you seek can be found by studying volumetric efficiency and head flow rates and the tool that will help you achieve those answers is called a cylinder head flow bench. Any engine builder worth their salt knows the biggest power gains are found in the head and the components that make it work. The Mercedes engineers we're not that tight lipped when they gave you the best suggestion they could, change the cam profile ! more lift and a longer duration equals more power. The bottom line is the horsepower you gain is directly proportional to the Limit of your finances and the physical limits of the m112.

 

I missed that you did the tb

 

The m112 has alot of potential, but the $$$$$$$ needed far it is greater than the rewards.
If it wasn't for the coding, soooo much would have been accomplished.
Why it took so long for a main company to to get coding and make ecu's and harnesses to swap a hemi into other vechicles. TY mb.
When chrysler finally split from mb then they let holley in so they could don't here thing.

 

I'm interested in what you mean here....

Given there are aftermarket ECU's that can easily handle V6's (Emerald K6 comes to mind); if this is a limitation I would like to investigate if those limitations can be resolved using a aftermarket ECU.

I'll keepa searching in the forum!

 

Would loose one of the better parts of the engine with the dual plugs that fire different times that made the engine one of most effecient engines per hp.

 

You are talking about spending a lot of money for very little performance improvement. Since you are talking about that route.... I suggest you look into changing the 3.2 shortblock for a 3.7 M112 from the ML350. That would give you more performance per dollar than the other mods you listed except for possibly the tune and cams.

 

No replacement for displacement.

 

A bone stock NA M112 with only 195 cu.in. performs the same as a V8 engine twice its size did 48 years ago.
Minimayhem, are you looking for lower 1/4 mile times, or more top end?
Do you have any documentation like time slips, or Dyno readouts to have a base line as to how your car is performing now?

 

[QUOTE=
1) port/polish the head
2) Fit 3-2-1 exhaust headers
3) High-flow cats (still trying to asses if these are even worth while to be honest, I'm curious if they will help more so because the cats are 10 years old vs being actually 'high flow)
4) Larger injectors (need to investigate cycle performance of the current ones, reading that at this point they are at max)
5) Further cool air intake (no idea how, need to figure out)
6) E55 fuel pump
7) ECU tune!
8) Karmaan camshafts[/QUOTE]

1.don't open the engine( if you do u will take off over 100000 mile life of the engine
2 exhaust does not help ,,but exhaust and headers will help.
3. with headers and if needed high flow cats are the way to go.
4. don't waste your money,, nothing to learn there. ( u already know how to do that)
5. a engine is a air pump u need it get air in and out needswings intake ,headers, exhaust
6. not needed, you could put a regulator (needswings fuel setup) increase fuel pressure to 65
7. yes but get a dyno tune ,,it is worth about 10 to 15 more hp than a can tune (on a srt)
8 again don't open the motor ,remember this is a hand built engine ,if you disturb it , you lose it.
9. change the rear gear ratio,, u now have a 3.27,,for faster top end /better gas mileage 3.07,,or 2.89 ( if auto u need tcu),,, to go faster from light to light 3.46
10. one step colder plugs.

jim

 

or you could just send to me your car( either miami or chicago) and a check for very close to what you will spend to do the mods the the v6,,,I'll, with Rudy install a V8 with a new V8 tranny turn key ,,you will now have a real learning experience. it will be faster than a modded srt6 but not as fast as a heavy modded srt6 jim